Patent Publication Number: US-2023151282-A1

Title: Multi-Stage Process and Device for Treatment Heavy Marine Fuel and Resultant Composition and the Removal of Detrimental Solids

Description:
This application is a continuation-in-part of co-pending U.S. application Ser. No. 16/103,891, filed 14 Aug. 2018; U.S. application Ser. No. 16/103,891 is a continuation-in-part of PCT/US2018/017863, filed 12 Feb. 2018, which claims benefit of U.S. Provisional Application No. 62/589,479, filed 21 Nov. 2017, and U.S. Provisional Application No. 62/458,002, filed 12 Feb. 2017; and U.S. application Ser. No. 16/103,891 is also a continuation-in-part of PCT/US2018/017855, filed 12 Feb. 2018, which claims benefit of U.S. Provisional Application No. 62/589,479, filed 21 Nov. 2017, and U.S. Provisional Application No. 62/458,002, filed 12 Feb. 2017, and the contents of all of the above referenced applications are expressly incorporated herein by reference. 
    
    
     BACKGROUND 
     There are two basic marine fuel types, distillate marine fuel, and residual marine fuel. Distillate marine fuels are subject to ISO 8217 (2017) Table 1, and may also be known as Marine Gas Oil (MGO) or Marine Diesel Oil (MDO). Distillate marine fuels comprise petroleum fractions separated from crude oil in a refinery via a distillation process having a boiling points generally less than 350° C. Gasoil (also known as medium diesel) is a petroleum distillate intermediate in boiling range and viscosity between kerosene and lubricating oil. Generally maximizing gasoil recovery from residues is the most economic use because a refinery can crack gas oils in an FCC unit into valuable gasoline and lighter distillates. Diesel oils are similar to gas oils with diesel containing a mixture of hydrocarbons, which include approximately 60% or more aliphatic hydrocarbons, 1-2% olefinic hydrocarbons, and 35% or less aromatic hydrocarbons. Marine Diesels must contain less than 15% by volume residual hydrocarbons (i.e. hdyrocarbons boiling above 350° C.), and optionally no over 5% volume of polycyclic aromatic hydrocarbons (asphaltenes). Diesel fuels are primarily utilized as a land transport fuel and as blending component with kerosene to form aviation jet fuel. 
     Residual marine fuels are often a complex mixture of a variety of hydrocarbons, the majority of which are the fractions boiling above 350° C. including those hydrocarbon fractions that don&#39;t boil or vaporize even under vacuum distillation conditions (called vacuum residue). The complex mixture of hydrocarbons that form residual marine fuels can include an asphaltenes content between 3 and 20 percent by weight. Asphaltenes are large and complex polycyclic hydrocarbons that contribute to the fuel density, SARA properties and lubricity properties which are desirable in residual marine fuels. Asphaltenes, however, have a propensity to form complex and waxy precipitates, especially when mixed with or exposed to aliphatic (paraffinic) hydrocarbons. In some commercial refinery operations this is a process known as deasphalting which is used to generate asphalt pitch or rock and deasphalted oils. In a maritime setting however, having asphaltenes precipitate out of residual marine fuel may create life threatening operational problems at sea. The precipitated asphaltenes are notoriously difficult to re-dissolve and are described as fuel tank sludge or fuel solids, or sediments in the marine shipping industry and marine bunker fueling industry. 
     Large ocean-going ships have relied upon residual marine fuels to power large two stroke diesel engines for over 50 years. Residual marine fuel (also know as Heavy Marine Fuel Oil (HMFO) is a complex blend of asphaltenes, polycyclic aromatics and residual hydrocarbons generated in the crude oil refinery process. Typical refinery streams included in the formulation of residual marine fuel include, but are not limited to: atmospheric tower bottoms (i.e. atmospheric residues), vacuum tower bottoms (i.e. vacuum residues) visbreaker residue, FCC Light Cycle Oil (LCO), FCC Heavy Cycle Oil (HCO) also known as FCC bottoms, FCC Slurry Oil, heavy gas oils; delayed cracker oil (DCO), polycylic aromatic hydrocarbons, De-asphalted oil (DAO); reclaimed land transport motor oils; slop oils, and minor portions (less than 20% vol.) of cutter oil, kerosene or diesel to achieve a desired viscosity. Residual marine fuel often has an aromatic content higher than the distillate marine fuels noted above. The exact hydrocarbon streams and chemical molecules within any given batch or lot of residual marine fuel may vary widely depending upon the source of crude oil processed by a refinery, the processes utilized within a refinery to extract the most value out of a barrel of crude oil, as well as any alternative (non-refinery) source, availability and cost of hydrocarbons that may be blended to form the final finish residual marine fuel. Regardless of the source of the various hydrocarbons blended to form a residual marine fuel, for that fuel to be commercially accepted by the marine fuel industry it must meet certain criteria set forth in the internationally accepted standard ISO 8217, the most recent of which is ISO 8217 (2017). The mixture of components is generally characterized as being viscous, high in sulfur and metal content, and high in asphaltenes making residual marine fuel one of the few products of the refining process that has a per barrel value less than the feedstock crude oil itself. 
     Industry statistics indicate that about 90% of the residual marine fuel sold contains 3.5 weight % sulfur. With an estimated total worldwide consumption of residual marine fuel of approximately 300 million tons per year the vast majority of which is ISO 8217 (2017) RMG 380, the annual production of sulfur dioxide by the shipping industry is estimated to be over 21 million tons per year. Emissions from ships burning high sulfur residual marine fuel contribute significantly to both global air pollution and local air pollution levels. 
     MARPOL, the International Convention for the Prevention of Pollution from Ships, as administered by the International Maritime Organization (IMO) was enacted to prevent pollution from ships. In 1997, a new annex was added to MARPOL; the Regulations for the Prevention of Air Pollution from Ships—Annex VI to minimize airborne emissions from ships and their contribution to air pollution. A revised Annex VI with tightened emissions limits on sulfur oxides, nitrogen oxides, ozone depleting substances and volatile organic compounds (SOx, NOx, ODS, VOC) was adopted in October 2008 and effective 1 Jul. 2010 (hereafter called Annex VI (revised)). 
     MARPOL Annex VI (revised) established a set of stringent emissions limits for vessel operations in designated Emission Control Areas (ECAs). The ECAs under MARPOL Annex VI (revised) are: i) Baltic Sea area—as defined in Annex I of MARPOL—SOx only; ii) North Sea area—as defined in Annex V of MARPOL—SOx only; iii) North American—as defined in Appendix VII of Annex VI of MARPOL—SOx, NOx and PM; and, iv) United States Caribbean Sea area—as defined in Appendix VII of Annex VI of MARPOL—SOx, NOx and PM. 
     Annex VI (revised) was codified in the United States by the Act to Prevent Pollution from Ships (APPS). Under the authority of APPS, the U.S. Environmental Protection Agency (the EPA), in consultation with the United States Coast Guard (USCG), promulgated regulations which incorporate by reference the full text of MARPOL Annex VI (revised). See 40 C.F.R. § 1043.100(a)(1). On Aug. 1, 2012 the maximum sulfur content of all marine fuels used onboard ships operating in US waters/ECA cannot exceed 1.00% wt. (10,000 ppm) and on Jan. 1, 2015 the maximum sulfur content of all marine fuels used in the North American ECA was lowered to 0.10% wt. (1,000 ppm). At the time of implementation, the United States government indicated that vessel operators must vigorously prepare for the 0.10% wt. (1,000 ppm) US ECA marine fuel sulfur standard. To encourage compliance, the EPA and USCG refused to consider the cost of compliant low sulfur fuel oil to be a valid basis for claiming that compliant fuel oil was not available for purchase. For the past five years there has been a very strong economic incentive to meet the marine industry demands for low sulfur residual marine fuel, however technically viable solutions have not been realized. There has been an on-going and urgent demand for processes and methods for making a low sulfur residual marine fuel compliant with ECA MARPOL Annex VI emissions requirements. 
     Under the revised MARPOL Annex VI, a global sulfur cap for residual marine fuel (the primary source for Sox emissions from ships) was set at 3.50% wt. effective 1 Jan. 2012; then further reduced to 0.50% wt, effective 1 Jan. 2020. This regulation has been the subject of much discussion in the marine shipping and marine fuel bunkering industry. There has been a strong economic incentive to meet the international marine industry demands for low sulfur residual marine fuel that is ISO 8217 Table 2 compliant, however technically viable solutions have not been realized. There is an on-going and urgent demand for processes and methods for making a low sulfur residual marine fuel ISO 8217 Table 2 compliant with the global MARPOL Annex VI emissions requirements. 
     Primary control solutions: A focus for compliance with the MARPOL requirements has been on primary control solutions for reducing the sulfur levels in marine fuel components prior to combustion based on the substitution of residual marine fuel with alternative fuels. Because of the potential risks to ships propulsion systems (i.e. fuel systems, engines, etc.) when a ship switches fuel, the conversion process must be done safely and effectively to avoid any technical issues. However, each alternative fuel has both economic and technical difficulties adapting to the decades of shipping infrastructure and bunkering systems based upon residual marine fuel utilized by the marine shipping industry. 
     Replacement of high sulfur residual marine fuel with marine gas oil or marine diesel: A third proposed primary solution is to simply replace high sulfur residual marine fuel with marine gas oil (MGO) or marine diesel (MDO). The first major difficulty is the constraint in global supply of distillate hydrocarbon materials that make up over 90% vol of MGO and MDO. It is reported that the effective spare capacity to produce MGO is less than 100 million metric tons per year resulting in an annual shortfall in marine fuel of over 200 million metric tons per year. Refiners not only lack the capacity to increase the production of MGO or MDO, but they have no economic motivation to increase production because higher value and higher margins can be obtained from ultra-low sulfur diesel fuel for land-based transportation systems (i.e. trucks, trains, mass transit systems, heavy construction equipment, etc.). A distillate only solution also ignores the economic impacts of disposing of the refinery streams that previously went to the high sulfur residual marine fuel blending pool. 
     Blending: Another primary solution is the optimized blending of various hydrocarbons with lower sulfur content hydrocarbons, such as low sulfur marine diesel (0.1% wt. sulfur) to achieve a residual marine fuel with a sulfur content of 0.5% wt. In a theoretical straight blending approach (based on linear blending) every 1 ton of high sulfur residual marine fuel (3.5% sulfur) requires 7.5 tons of low sulfur MGO or MDO material with 0.1% wt. S to achieve a sulfur level of 0.5% wt. in the final residual marine fuel blended product. One of skill in the art of fuel blending will immediately understand that blending large volumes of distillate hydrocarbons into high sulfur residual marine fuels hurts key properties of the residual marine fuel, specifically lubricity, viscosity and density are substantially altered. Further a blending process may create a fuel that is unstable and incompatible with other lots or types of blended low sulfur residual marine fuel. A blended residual marine fuel is likely to result in the precipitation of asphaltenes and/or waxing out of highly paraffinic materials from the distillate material forming an intractable fuel tank sludge. Such a risk to the primary propulsion system is not acceptable for a cargo ship in the open ocean. 
     Processing of residual oils. For the past several decades, the focus of refining industry research efforts related to the processing of heavy oils (crude oils, distressed oils, or residual oils) has been on upgrading the properties of these low value refinery process oils to create lighter oils with greater value. The challenge has been that crude oil, distressed oil and residues can be unstable and contain high levels of sulfur, nitrogen, phosphorous, metals (especially vanadium and nickel) and asphaltenes. Much of the nickel and vanadium is in difficult to remove chelates with porphyrins. Vanadium and nickel porphyrins and other metal organic compounds are responsible for catalyst contamination and corrosion problems in the refinery. The sulfur, nitrogen, and phosphorous, are removed because they are well-known poisons for the precious metal (platinum and palladium) catalysts utilized in the processes downstream of the atmospheric or vacuum distillation towers. 
     The difficulties treating atmospheric or vacuum residual streams has been known for many years and has been the subject of considerable research and investigation. A major problem associated with the catalytic hydrogenation of the heavier fractions of petroleum is the complexity of the feed and in ability to carry out speciation or molecular analysis on such a complex mixture of large, high boiling point hydrocarbons. Numerous residue/heavy oil conversion processes have been developed in which the goals are same, 1) create a more valuable lower boiling point fractions, preferably distillate range hydrocarbon product; and 2) concentrate the contaminates such as sulfur, nitrogen, phosphorous, metals and asphaltenes into a form or high boiling point fraction (coke, heavy coker residue, FCC slurry oil, vacuum residue, residues, etc.) for removal from the refinery stream. The main problems associated with hydroprocessing this very broad range of residual streams includes the presence of polyaromatics, asphaltenes, and heteroatoms leads to the excessive coking of the catalyst (and subsequent plugging of the reactor) and rapid deactivation of the catalyst. Well known and accepted practice in the refining industry to prevent coking of the catalyst is to increase the reaction severity (elevated temperature and pressure) to produce hydrocarbon products that are lighter and more purified, increase catalyst life times and remove sulfur, nitrogen, phosphorous, metals and asphaltenes from the refinery stream. Sometimes this is intentionally done in situ in a process reactor in a process called hot hydrogen stripping, although this practice is not universally accepted because of costs, latent damage to the catalysts, and safety risks associated with a hot, hydrogen gas rich environment (i.e. hydrogen embrittlement of certain steels and alloys). 
     One industry accepted measure of the success of a hydroconversion or hydrocracking process is to measure the conversion rate. Hydroconversion is a term used to describe the processes in which molecules of petroleum feedstocks are cracked or saturated with hydrogen, diminishing boiling point ranges and impurities in the feedstock. The conversion rate for such a process is typically defined as being the quantity of compounds having a boiling point greater then 520 C in the hydrocarbon containing feedstock into the processing unit, minus the quantity of compounds having a boiling point greater than 520 C in the hydrocarbon product coming out of the processing unit, all divided by the quantity of compounds having a boiling point greater than 520 C in the hydrocarbon containing feedstock into the processing unit and then expressed as a percentage. In the prior art, a high conversion rate is advantageous and desirable insofar as this conversion rate illustrates the hydrocracking and conversion of residual hydrocarbons (i.e. residue or vacuum residue having a boiling point greater than 520 C) which is a low value hydrocarbon to a more valuable naphtha (boiling point less than 150° C.) and diesel (boiling point from 150°-350° C.) hydrocarbon fractions. Conversion rates lower than 30% are unacceptable on both technical and commercial basis. Conversion rates up to 40% may be considered very low to unacceptable on a commercial basis depending on the consumption of hydrogen by the process and the goal for hydrotreating (i.e. desulfurization, denitrogenation, demetallization, reduction in Conradson carbon, aromatic saturation, etc. . . . ) the feedstock. Most conversion rate objectives for the hydrocracking aspects of a hydroprocessing system are greater than 40% conversion, preferably as high as greater than 70% and more preferably in the range of 85% to 99% conversion. For example see paragraphs 0142 and 0143 in US20160122666 and other related disclosures and technical articles on the hydroconversion of residues and heavy oils. 
     In summary, since the announcement of the MARPOL standards reducing the global levels of sulfur in residual marine fuel, refiners of crude oil have been unsuccessful in their technical efforts to create a process for the production of a low sulfur substitute for high sulfur residual marine fuel. Despite the strong governmental and economic incentives and needs of the international marine shipping industry, refiners have little economic reason to address the removal of environmental contaminates from residual marine fuel. The global refining industry has been focused upon generating greater value from each barrel of oil by creating light hydrocarbons (i.e. diesel and gasoline) and concentrating the environmental contaminates into increasingly lower value streams (i.e. residues) and products (petroleum coke, high sulfur residual marine fuel). Shipping companies have focused on short term solutions, such as the installation of scrubbing units, or adopting the limited use of more expensive low sulfur marine diesel and marine gas oils as a substitute for high sulfur residual marine fuel. On the open seas, most if not all major shipping companies continue to utilize the most economically viable fuel, that is high sulfur residual marine fuel. There remains a long standing and unmet need for processes and devices that remove the environmental contaminants (i.e. sulfur, nitrogen, phosphorous, metals especially vanadium and nickel) from residual marine fuel without altering the qualities and properties that make residual marine fuel the most economic and practical means of powering ocean going vessels. 
     SUMMARY 
     It is a general objective to reduce the environmental contaminates and Detrimental Solids from a ISO 8217 (2017) Table 2 compliant residual marine fuel, also referred to herein as a Heavy Marine Fuel Oil (HMFO) in a multi stage process that minimizes the changes in the desirable properties of the residual marine fuel and minimizes the unnecessary production of by-product hydrocarbons (i.e. light hydrocarbons having C1-C4 and naphtha all having a boiling point less than 150° C.). One correlation with the ability of the process to retain the desirable properties of the residual marine fuel may be measured by a conversion rate of less than 40% and preferably less than 30% and more preferably less than 20%. Other correlations exist with combustion and ignition properties of the resulting residual marine fuel. 
     A first aspect and illustrative embodiment encompasses a multi-stage process for reducing the environmental contaminants and Detrimental Solids in a Feedstock Heavy Marine Fuel Oil, the process involving: contacting a Feedstock Heavy Marine Fuel Oil with a Detrimental Solids Removal Unit (DSRU) to give a pre-treated Feedstock Heavy Marine Fuel Oil; mixing a quantity of the pre-treated Feedstock Heavy Marine Fuel Oil with a quantity of Activating Gas mixture to give a Feedstock Mixture; contacting the Feedstock Mixture with one or more catalysts under desulfurizing conditions to form a Process Mixture from the Feedstock Mixture; receiving the Process Mixture and separating the Product Heavy Marine Fuel Oil liquid components of the Process Mixture from the gaseous components and by-product hydrocarbon components of the Process Mixture and, discharging the Product Heavy Marine Fuel Oil. 
     A second aspect and illustrative embodiment encompasses a device for reducing Environmental Contaminants and Detrimental Solids in a Feedstock HMFO and producing a Product HMFO. The illustrative devices embody the above illustrative processes on a commercial scale. 
     A third aspect and illustrative embodiment encompasses a Heavy Marine Fuel Oil composition resulting from the above illustrative processes. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a process block flow diagram of an illustrative core process to produce Product HMFO. 
         FIG.  2    is a process flow diagram of a multistage process utilizing a Detrimental Solids Removal Unit to pre-treat the Feedstock HMFO and a subsequent core process to produce Product HMFO. 
         FIG.  3    is a diagram illustrating the details of a Detrimental Solids Removal Unit. 
         FIG.  4    is a basic schematic diagram of a plant to produce Product HMFO utilizing a combination of a Detrimental Solids Removal Unit to pre-treat the Feedstock HMFO and a subsequent core process to produce Product HMFO. 
         FIG.  5    is a basic schematic diagram of a plant to produce Product HMFO utilizing a combination of a Core Process and a subsequent Detrimental Solids Removal Unit to produce Product HMFO. 
     
    
    
     DETAILED DESCRIPTION 
     The inventive concepts as described herein utilize terms that should be well known to one of skill in the art, however certain terms are utilized having a specific intended meaning and these terms are defined below: 
     Heavy Marine Fuel Oil (HMFO) also known as residual marine fuel or heavy marine fuel is a petroleum product fuel compliant with the ISO 8217 (2017) Table 2 standards for the properties of residual marine fuels except for the concentration levels of the Environmental Contaminates such as sulfur, alumina silica, and metals. 
     Detrimental Solids are suspended solid particulate materials present in a HMFO having a diameter in the range of 1000 microns to 0.1 microns. 
     Environmental Contaminates are organic and inorganic components of a HMFO that result in the formation of SO x , NO x  and particulate materials upon combustion. 
     Feedstock HMFO is a petroleum product fuel compliant with the ISO 8217 (2017) Table 2 standards for the properties of residual marine fuels except for the concentration of Environmental Contaminates, preferably the Feedstock HMFO has a sulfur content greater than the global MARPOL standard of 0.5% wt. sulfur, and preferably and has a sulfur content (ISO 14596 or ISO 8754) between the range of 5.0% wt. to 1.0% wt. 
     Product HMFO is a petroleum product fuel compliant with the ISO 8217 (2017) Table 2 standards for the properties of residual marine fuels and achieves a sulfur content lower than the global MARPOL standard of 0.5% wt. sulfur (ISO 14596 or ISO 8754), and preferably a maximum sulfur content (ISO 14596 or ISO 8754) between the range of 0.05% wt. to 0.5% wt. 
     Activating Gas: is a mixture of gases utilized in the process combined with the catalyst to remove the environmental contaminates from the Feedstock HMFO. 
     Fluid communication: is the capability to transfer fluids (either liquid, gas or combinations thereof, which might have suspended solids) from a first vessel or location to a second vessel or location, this may encompass connections made by pipes (also called a line), spools, valves, intermediate holding tanks or surge tanks (also called a drum). 
     Merchantable quality: is a level of quality for a residual marine fuel so the fuel is tit for the ordinary purpose it should serve (i.e. serve as a residual marine fuel for a marine ship) and can be commercially sold as and is fungible (compatible and miscible) with other heavy or residual marine fuels and more preferably with distillate marine fuels. 
     Bbl or bbl: is a standard volumetric measure for oil; 1 bbl=0.1589873 m 3 ; or 1 bbl=158.9873 liters; or 1 bbl=42.00 US liquid gallons. 
     Bpd: is an abbreviation for Bbl per day. 
     SCF: is an abbreviation for standard cubic foot of a gas; a standard cubic foot (at 14.73 psi and 60° F.) equals 0.0283058557 standard cubic meters (at 101.325 kPa and 15° C.). 
     The inventive concepts are illustrated in more detail in this description referring to the drawings, in which  FIG.  1    shows the generalized block process flows for a core process of reducing the environmental contaminates in a Feedstock HMFO and producing a Product HMFO. A predetermined volume of Feedstock HMFO ( 2 ) is mixed with a predetermined quantity of Activating Gas ( 4 ) to give a Feedstock Mixture. The Feedstock HMFO utilized generally complies with the bulk physical and certain key chemical properties for a residual marine fuel otherwise compliant with ISO 8217 (2017) Table 2 exclusive of the Environmental Contaminates. More particularly, when the Environmental Contaminate is sulfur, the concentration of sulfur in the Feedstock HMFO may be between the range of 5.0% wt. to 1.0% wt. Except for the Environmanetal Contaminants, the Feedstock HMFO should have the properties required of an ISO 8217 (2017) Table 2 compliant HMFO. This includes having properties of: a kinematic viscosity at 50° C. (ISO 3104) between the range from 180 mm 2 /s to 700 mm 2 /s; a density at 15° C. (ISO 3675) between the range of 991.0 kg/m 3  to 1010.0 kg/m 3 ; a CCAI in the range of 780 to 870; a flash point (ISO 2719) no lower than 60° C.; a maximum total sediment—aged (ISO 10307-2) of less than 0.10% wt. and a maximum carbon residue—micro method (ISO 10370) less than 20% wt. and preferably less than 18% wt. In one embodiment, the Feedstock HMFO may have any combination of density and kinematic viscosity that results in a CCAI in the range of 780 to 870. Environmental Contaminates other than sulfur that may be present in the Feedstock HMFO over the ISO requirements may include vanadium, nickel, iron, aluminum and silicon substantially reduced by the process of the present invention. However, one of skill in the art will appreciate that the vanadium content serves as a general indicator of these other Environmental Contaminates. In one preferred embodiment the vanadium content is ISO compliant so the Feedstock MHFO has a vanadium content (ISO 14597) between the range from 350° mg/kg to 450 ppm mg/kg. 
     As for the properties of the Activating Gas, the Activating Gas should be selected from mixtures of nitrogen, hydrogen, carbon dioxide, gaseous water, and methane. The mixture of gases within the Activating Gas should have an ideal gas partial pressure of hydrogen (pH2) greater than 80% of the total pressure of the Activating Gas mixture (P) and more preferably wherein the Activating Gas has an ideal gas partial pressure of hydrogen (pH2) greater than 90% of the total pressure of the Activating Gas mixture (P). It will be appreciated by one of skill in the art that the molar content of the Activating Gas is another criteria the Activating Gas should have a hydrogen mole fraction in the range between 80% and 100% of the total moles of Activating Gas mixture. 
     A mixture of Feedstock HMFO and Activating Gas is brought up to the process conditions of temperature and pressure by a combination of steps involving the heating and mixing of the two in any order or manner known to a skilled person and introduced into a first vessel, preferably a reactor vessel, so the Feedstock Mixture is then contacted with one or more catalysts ( 8 ) to form a Process Mixture from the Feedstock Mixture. Alternatively, the Feedstock HMFO can be heated and introduced separately (unmixed with) the Activating gas into a reactor vessel and the mixing with Activating Gas takes place in the reactor vessel prior to contacting the catalyst. One of skill will know or appreciate that in some instances, the Activating Gas may be introduced in between beds of catalyst in the reactor vessel as well to help quench the system. Alternative ways of combining the Feedstock HMFO, the Activating Gas and the catalysts under reactive conditions may also be used such as gas saturation of the feed or liquid full processes that are well known and have been commercially used for diesel hydroprocessing. 
     The core process reactive conditions are selected so the ratio of the quantity of the Activating Gas to the quantity of Feedstock HMFO is 250 scf gas/bbl of Feedstock HMFO to 10,000 scf gas/bbl of Feedstock HMFO; and preferably between 2000 scf gas/bbl of Feedstock HMFO 1 to 5000 scf gas/bbl of Feedstock HMFO more preferably between 2500 scf gas/bbl of Feedstock HMFO to 4500 scf gas/bbl of Feedstock HMFO. The process conditions are selected so the total pressure in the first vessel is between of 250 psig and 3000 psig; preferably between 1000 psig and 2500 psig, and more preferably between 1500 psig and 2200 psig. The process reactive conditions are selected so the indicated temperature within the first vessel is between of 500° F. to 900° F., preferably between 650° F. and 850° F. and more preferably between 680° F. and 800° F. The process conditions are selected so the liquid hourly space velocity within the first vessel is between 0.05 h 1  and 1.0 h 1 ; preferably between 0.08 h 1  and 0.5 h h −1 ; and more preferably between 0.1 h 1  and 0.3 h 1  to achieve deep desulfurization with product sulfur levels below 0.1 ppmw. The reactive conditions are further optimized to the feedstock materials with the objective being to minimize the hydroconversion of the fractions boiling above 520 C to naphtha fractions (boiling point less than 150° C.) and light diesel fractions (boiling point less than 250 C) to a conversion rate of less than 15% by mass, preferably less than 10% by mass and more preferably less than 5% by mass, based on the overall mass balance. In one illustrative embodiment reaction conditison are selected such that the conversion rate (as defined above) is less than 30%, preferably less than 25%, and more preferably less than 20%. This is in marked contrast with the known prior art processes and conditions utilized for the hydroprocessing of residues, heavy crude oils, and heavy hydrocarbons in general which seek to achieve conversion rates greater than 30% and in vast majority of instances, conversion rates as great as 90% or even 99%. (See for example patents and technical papers on the “EST” heavy oil process owned and patented by ENI, or the “H-Oil” process marketed by Axens or the “LC-MAX” or “LC-SLURRY” technologies of Chevron Lummus Group). 
     One of skill in the art will appreciate that the core process reactive conditions are determined to consider the hydraulic capacity of the unit. Exemplary hydraulic capacity for the treatment unit may be between 100 bbl of Feedstock HMFO/day and 100,000 bbl of Feedstock HMFO/day, preferably between 1000 bbl of Feedstock HMFO/day and 60,000 bbl of Feedstock HMFO/day, more preferably between 5,000 bbl of Feedstock HMFO/day and 45,000 bbl of Feedstock HMFO/day, and even more preferably between 10,000 bbl of Feedstock HMFO/day and 30,000 bbl of Feedstock HMFO/day. 
     The core process may utilize one or more catalyst systems selected from the group consisting of: an ebulliated bed supported transition metal heterogeneous catalyst, a fixed bed supported transition metal heterogeneous catalyst, and a combination of ebulliated bed supported transition metal heterogeneous catalysts and fixed bed supported transition metal heterogeneous catalysts. One of skill in the art will appreciate that a fixed bed supported transition metal heterogeneous catalyst will be the technically easiest to implement and is preferred. The transition metal heterogeneous catalyst comprises a porous inorganic oxide catalyst carrier and a transition metal catalyst. The porous inorganic oxide catalyst carrier is at least one carrier selected from the group consisting of alumina, alumina/boria carrier, a carrier containing metal-containing aluminosilicate, alumina/phosphorus carrier, alumina/alkaline earth metal compound carrier, alumina/titania carrier and alumina/zirconia carrier. The transition metal component of the catalyst is one or more metals selected from the group consisting of group 6, 8, 9 and 10 of the Periodic Table. In a preferred and illustrative embodiment, the transition metal heterogeneous catalyst is a porous inorganic oxide catalyst carrier and a transition metal catalyst, in which the preferred porous inorganic oxide catalyst carrier is alumina and the preferred transition metal catalyst is Ni—Mo, Co—Mo, Ni—W or Ni—Co—Mo. 
     The Process Mixture ( 10 ) in this core process is removed from the first vessel ( 8 ) and from being in contact with the one or more catalyst materials and is sent via fluid communication to a second vessel ( 12 ), preferably a gas-liquid separator or hot separators and cold separators, for separating the liquid components ( 14 ) of the Process Mixture from the bulk gaseous components ( 16 ) of the Process Mixture. The gaseous components ( 16 ) are treated beyond the battery limits of the immediate process. Such gaseous components may include a mixture of Activating Gas components and lighter hydrocarbons (mostly methane, ethane and propane but some naphtha) that may have been formed as part of the by-product hydrocarbons from the process. 
     The Liquid Components ( 16 ) in this core process are sent via fluid communication to a third vessel ( 18 ), preferably a fuel oil product stripper system, for separating any residual gaseous components ( 20 ) and by-product hydrocarbon components ( 22 ) from the Product HMFO ( 24 ). The residual gaseous components ( 20 ) may be a mixture of gases selected from the group consisting of: nitrogen, hydrogen, carbon dioxide, hydrogen sulfide, gaseous water, C1-C5 hydrocarbons. This residual gas is treated outside of the battery limits of the immediate process, combined with other gaseous components ( 16 ) removed from the Process Mixture ( 10 ) in the second vessel ( 12 ). The liquid by-product hydrocarbon component, which are condensable hydrocarbons formed in the process ( 22 ) may be a mixture selected from the group consisting of C4-C20 hydrocarbons (naphtha and naphtha—light diesel) and other condensable light liquid (C4-C8) hydrocarbons that can be utilized as part of the motor fuel blending pool or sold as gasoline and diesel blending components on the open market. These liquid by-product hydrocarbons should be less than 15% wt, preferably less than 5% wt. and more preferably less than 3% wt. of the overall process mass balance. 
     The Product HMFO ( 24 ) resulting from the core process is discharged via fluid communication into storage tanks beyond the battery limits of the immediate process. The Product HMFO complies with ISO 8217 (2017) and has a sulfur content (ISO 14596 or ISO 8754) between the range of 0.05 mass % to 1.0 mass % preferably a sulfur content (ISO 14596 or ISO 8754) between the range of 0.05 mass % ppm and 0.7 mass % and more preferably a sulfur content (ISO 14596 or ISO 8754) between the range of 0.1 mass % and 0.5 mass %. The vanadium content of the Product HMFO is also ISO compliant with a maximum vanadium content (ISO 14597) between the range from 350° mg/kg to 450 ppm mg/kg, preferably a vanadium content (ISO 14597) between the range of 200 mg/kg and 300 mg/kg and more preferably a vanadium content (ISO 14597) less than 50 mg/kg. 
     The Product HFMO should have properties that are ISO 8217 (2017) Table 2 compliant, and preferably: a maximum of kinematic viscosity at 50° C. (ISO 3104) between the range from 180 mm 2 /s to 700 mm 2 /s; a maximum of density at 15° C. (ISO 3675) between the range of 991.0 kg/m 3  to 1010.0 kg/m 3 ; a CCAI in the range of 780 to 870; a flash point (ISO 2719) no lower than 60° C.; a total sediment—aged (ISO 10307-2) of less than 0.10% wt.; a carbon residue—micro method (ISO 10370) less than 20.00% wt. In one embodiment, the Product HMFO may have any combination of density and kinematic viscosity that results in a CCAI in the range of 780 to 870 in addition to the other properties required of an ISO 8217 (2017) Table 2 residual marine fuel. Relative to the Feedstock HMFO, the Product HMFO will have a sulfur content (ISO 14596 or ISO 8754) between 1% and 20% of the maximum sulfur content of the Feedstock HMFO. That is the sulfur content of the Product HMFO will be reduced by about 80% or greater when compared to the Feedstock HMFO. Similarly, the vanadium content (ISO 14597) of the Product Heavy Marine Fuel Oil is between 1% and 20% of the maximum vanadium content of the Feedstock Heavy Marine Fuel Oil. One of skill in the art will appreciate that the above data indicates a substantial reduction in sulfur and vanadium content indicative of a process achieving a substantial reduction in the Environmental Contaminates from the Feedstock HMFO while maintaining the desirable combustion characteristics and properties of an ISO 8217(2017) Table 2 compliant residual marine fuel. 
     As a side note, the residual gaseous component is a mixture of gases selected from the group consisting of: nitrogen, hydrogen, carbon dioxide, hydrogen sulfide, gaseous water, C1-C5 hydrocarbons. An amine scrubber will effectively remove the hydrogen sulfide content which can then be processed using technologies and processes well known to one of skill in the art. In one preferable illustrative embodiment, the hydrogen sulfide is converted into elemental sulfur using the well-known Claus process. An alternative embodiment utilizes a proprietary process for conversion of the Hydrogen sulfide to hydrosulfuric acid. Either way, the sulfur is prevented from entering the environment prior to combusting the HMFO in a ships engine and may be utilized as a feedstock to other process or converted to solid elemental sulfur. The cleaned gas can be vented, flared or more preferably recycled back for use as Activating Gas. 
     Detrimental Solids Removal Process: It will be appreciated by one of skill in the art, that the conditions utilized in the core process have been intentionally selected to minimize cracking of hydrocarbons, but remove significant levels of sulfur from the Feedstock HMFO. However, one of skill in the art will also appreciate there may be certain Detrimental Solids present in the Feedstock HMFO removal of which would have a positive impact upon the desirable bulk properties of the Product HMFO. These processes and systems must achieve this without substantially altering the desirable bulk properties (i.e. compliance with ISO 8217 (2017) exclusive of sulfur content) of the Product HMFO. 
     The Detrimental Solids Removal Unit (DSRU) itself may be stand alone or it may be incorporated into the reactor vessel as guard bed. When incorporated into a reactor vessel, the DSRU may be one or more densely packed beds of inert catalyst material or other solids that act as filter media. As a stand alone unit, the DSRU may be a reactor vessel with multiple densely packed beds of filtering materials such as inert catalysts or it may be as described in U.S. Pat. No. 5,074,989 which comprises a filtration module with a plurality of filtration barriers aligned the length of the filtration cell. The filtrate is that portion of the feedstock passing through the filtration barriers, preferably from interior to exterior driven by a pressure drop across the filtration barriers. The filtration barriers may be mineral based filtration barriers such as those disclosed in U.S. Pat. No. 5,074,989, or they may be porous sintered metal filters or a combination of the two. The porosity of the filtration barriers is characterized by the permeametric radii of the pores. This reflects size of pores and the diameter of particles that can transit the filtration barrier. Commercially available mineral barriers having a permeametric radii from 2-100 nm (ultrafiltration) and 0.1-100 microns (microfiltration) will be useful. One of skilled in the art will also appreciate that staging the filtration barriers so the HMFO is first microfiltered followed by ultrafiltration will prolong the life of the filter and maximize the efficiency of the DSRU. Construction of a DSRU, which may operate at relatively pressures lower than 2 MPa, and temperatures equal to or lower than 300° C., adopted in this process would not present technical difficulties for an experienced technician in this field 
     In this description, items already described above as part of the core process have retained the same numbering and designation for ease of description. As show in  FIG.  2   , a DSRU  3  can be utilized to pre-treat the Feedstock HMFO prior to mixing with the Activating Gas  4  as part of the core process disclosed above. While simplistically represented in this drawing, the DSRU  3  may be multiple parallel or in series DSRUs however the DSRU may be as simple as a single reactor vessel in which the HMFO is filtered through a bed of inert or inactive catalyst materials prior to exposure to the reactors containing active catalyst materials. While a single a fixed bed, flow through/contact vessel may be used, it may be advantageous and it is preferable to have multiple contact vessels in parallel with each other to allow for one unit to be active while a second or third unit are being reloaded. Such an arrangement involving multiple parallel contact vessels with pipes/switching valves, etc. . . . is well within the abilities of one of skill in the art of refinery process design and operation. 
     Product HMFO The Product HFMO resulting from the disclosed illustrative process is of merchantable quality for sale and use as a heavy marine fuel (also known as a residual marine fuel or heavy bunker fuel) and exhibits the physical properties required for the Product HMFO to be an ISO compliant (i.e. ISO8217:2017 Table 2) residual marine fuel. The Product HMFO will exhibit bulk properties of: a kinematic viscosity at 50° C. (ISO 3104) between the range from 180 mm 2 /s to 700 mm 2 /s; a density at 15° C. (ISO 3675) between the range of 991.0 kg/m 3  to 1010.0 kg/m 3 ; a CCAI in the range of 780 to 870; a flash point (ISO 2719) no lower than 60° C.; a total sediment—aged (ISO 10307-2) of less than 0.10% wt.; a carbon residue—micro method (ISO 10370) less than 20.00% wt. and preferably less than 18%, and aluminum plus silicon (ISO 10478) content less than 60 mg/kg. In one embodiment, the Product HMFO may have any combination of density and kinematic viscosity that results in a CCAI in the range of 780 to 870, but is otherwise compliant with ISO 8217 (2017) Table 2. 
     The Product HMFO has a sulfur content (ISO 14596 or ISO 8754) less than 0.5 wt % and preferably less than 0.1% wt. and complies with the IMO Annex VI (revised) requirements for a low sulfur and preferably an ultra-low sulfur HMFO. That is the sulfur content of the Product HMFO has been reduced by about 80% or greater when compared to the Feedstock HMFO. Similarly, the vanadium content (ISO 14597) of the Product Heavy Marine Fuel Oil is less than 20% and more preferably less than 1% of the maximum vanadium content of the Feedstock Heavy Marine Fuel Oil. One of skill in the art will appreciate that a substantial reduction in sulfur and vanadium content of the Feedstock HMFO indicates a process having achieved a substantial reduction in the Environmental Contaminates from the Feedstock HMFO; of equal importance is this has been achieved while maintaining the desirable properties of an ISO 8217 (2017) Table 2 compliant HMFO. 
     The Product HMFO not only complies with ISO 8217 (2017) Table 2 (and is merchantable as a residual marine fuel or bunker fuel). The Product HMFO has a maximum sulfur content (ISO 14596 or ISO 8754) between the range of 0.05% wt. to 1.0% wt. preferably is IMO compliant with a sulfur content (ISO 14596 or ISO 8754) between the range of 0.05% wt. ppm and 0.5% wt. and more preferably a sulfur content (ISO 14596 or ISO 8754) between the range of 0.1% wt. and 0.5% wt. The vanadium content of the Product HMFO is well within the maximum vanadium content (ISO 14597) required for an ISO 8217 (2017) residual marine fuel exhibiting a vanadium content lower than 450 ppm mg/kg, preferably a vanadium content (ISO 14597) lower than 300 mg/kg and more preferably a vanadium content (ISO 14597) less than 50 mg/kg. 
     One knowledgeable in the art of marine fuel blending, bunker fuel formulations and the fuel logistical requirements for marine shipping fuels will readily appreciate that without further compositional changes or blending, the Product HMFO can be sold and used as a low sulfur MARPOL Annex VI compliant heavy (residual) marine fuel that is a direct substitute for the high sulfur heavy (residual) marine fuel or heavy bunker fuel currently in use. One illustrative embodiment is an ISO 8217 (2017) Table 2 compliant low sulfur residual marine fuel comprising (and preferably consisting essentially of) a hydroprocessed ISO 8217 (2017) Table 2 compliant high sulfur residual marine fuel, wherein the sulfur levels of the hydroprocessed ISO 8217 (2017) Table 2 compliant high sulfur heavy marine fuel is greater than 0.5% wt. and wherein the sulfur levels of the ISO 8217 (2017) Table 2 compliant low sulfur heavy marine fuel is less than 0.5% wt. Another illustrative embodiment is an ISO 8217 (2017) Table 2 compliant ultra-low sulfur residual marine fuel comprising (and preferably consisting essentially of) a 100% hydroprocessed ISO 8217 (2017) Table 2 compliant high sulfur heavy marine fuel, wherein the sulfur levels of the hydroprocessed ISO 8217 (2017) Table 2 compliant high sulfur heavy marine fuel is greater than 0.5% wt. and wherein the sulfur levels of the ISO 8217 (2017) Table 2 compliant low sulfur heavy marine fuel is less than 0.1% wt. Another illustrative embodiment is an ISO 8217 (2017) Table 2 compliant residual marine fuel product comprising (and preferably consisting essentially of) an ISO 8217 (2017) Table 2 compliant high sulfur heavy marine fuel that has hydroprocessed under reactive conditions such that the conversion rate is less than 30% and preferably less than 25% and more preferably less than 20%, and wherein the sulfur levels of the ISO 8217 (2017) Table 2 compliant high sulfur heavy marine fuel subjected to hydroprocessing is greater than 0.5% wt., and wherein the sulfur levels of the ISO 8217 (2017) Table 2 compliant residual marine fuel product is less than 0.5 wt % and preferably less than 0.1% wt. 
     Because of the present invention, multiple economic and logistical benefits to the bunkering and marine shipping industries can be realized. The benefits include minimal changes to the existing heavy marine fuel bunkering infrastructure (storage and transferring systems); minimal changes to shipboard systems are needed to comply with emissions requirements of MARPOL Annex VI no additional training or certifications for crew members will be needed, amongst the realizable benefits. Refiners will also realize multiple economic and logistical benefits, including: no need to alter or rebalance the refinery operations and product streams to meet a new market demand for low sulfur or ultralow sulfur HMFO; no additional units are needed in the refinery with additional hydrogen or sulfur capacity because the illustrative process can be conducted as a stand-alone unit; refinery operations can remain focused on those products that create the greatest value from the crude oil received (i.e. production of petrochemicals, gasoline and distillate (diesel); refiners can continue using the existing slates of crude oils without having to switch to sweeter or lighter crudes to meet the environmental requirements for HMFO products. 
     Heavy Marine Fuel Composition One aspect of the present inventive concept is a fuel composition comprising, but preferably containing a majority of, the Product HMFO resulting from the processes disclosed, and may optionally include Diluent Materials. As noted above the properties of the Product HMFO itself complies with ISO 8217 (2017) Table 2 and meets the global IMO Annex VI requirements for maximum sulfur content (ISO 14596 or ISO 8754). If ultra low levels of sulfur (i.e. less than 0.1 wt %) are desired, the process of the present invention achieves this. However, one of skill in the art of marine fuel blending will appreciate that a low sulfur or ultra-low sulfur Product HMFO can be utilized as a primary blending stock to form a global IMO Annex VI compliant low sulfur (sulfur content less than 0.5 wt %) ISO 8217 (2017) Table 2 compliant residual marine fuel by blending with other compatible hydrocarbons to form a “Heavy Marine Fuel Composition”. Such a low sulfur Heavy Marine Fuel Composition will comprise (and preferably consist essentially of): a) the Product HMFO as noted above and b) Diluent Materials. In one embodiment, the majority of the volume of the Heavy Marine Fuel Composition is the Product HMFO with the balance of materials being Diluent Materials. Preferably, the Heavy Marine Fuel Composition is at least 75% by volume, preferably at least 80% by volume, more preferably at least 90% by volume, and furthermore preferably at least 95% by volume Product HMFO with the balance being Diluent Materials. 
     Diluent Materials may be hydrocarbon or non-hydrocarbon based materials mixed into or combined with or added to, or solid particle materials suspended in, the Product HMFO. The Diluent Materials may intentionally or unintentionally alter the composition of the Product HMFO but not so the resulting mixture violates the ISO 8217 (2017) standards for the bulk properties of residual marine fuels or fails to have a sulfur content lower than the global MARPOL standard of 0.5% wt. sulfur (ISO 14596 or ISO 8754). Examples of Diluent Materials considered hydrocarbon based materials include: Feedstock HMFO (i.e. high sulfur HMFO); distillate based fuels such as road diesel, gas oil, MGO or MDO; cutter oil (which is used in formulating residual marine fuels); renewable oils and fuels such as biodiesel, methanol, ethanol; synthetic hydrocarbons and oils based on gas to liquids technology such as Fischer-Tropsch derived oils, synthetic oils such as those based on polyethylene, polypropylene, dimer, trimer and poly butylene; refinery residues or other hydrocarbon oils such as atmospheric residue, vacuum residue, fluid catalytic cracker (FCC) slurry oil, FCC cycle oil, pyrolysis gasoil, cracked light gas oil (CLGO), cracked heavy gas oil (CHGO), light cycle oil (LCO), heavy cycle oil (HCO), thermally cracked residue, coker heavy distillate, bitumen, de-asphalted heavy oil, visbreaker residue, slop oils, asphaltinic oils; used or recycled motor oils; lube oil aromatic extracts and crude oils such as heavy crude oil, distressed crude oils and similar materials that might otherwise be sent to a hydrocracker or diverted into the blending pool for a prior art high sulfur heavy (residual) marine fuel. Examples of Diluent Materials considered non-hydrocarbon based materials include: residual water (i.e. water absorbed from the humidity in the air or water that is miscible or solubilized, sometimes as microemulsions, into the hydrocarbons of the Product HMFO), fuel additives which can include, but are not limited to detergents, viscosity modifiers, pour point depressants, lubricity modifiers, de-hazers (e.g. alkoxylated phenol formaldehyde polymers), antifoaming agents (e.g. polyether modified polysiloxanes); ignition improvers; anti rust agents (e.g. succinic acid ester derivatives); corrosion inhibitors; anti-wear additives, anti-oxidants (e.g. phenolic compounds and derivatives), coating agents and surface modifiers, metal deactivators, static dissipating agents, ionic and nonionic surfactants, stabilizers, cosmetic colorants and odorants and mixtures of these. A third group of Diluent Materials may include suspended solids or fine particulate materials that are present because of the handling, storage and transport of the Product HMFO or the Heavy Marine Fuel Composition, including but not limited to: carbon or hydrocarbon solids (e.g. coke, graphitic solids, or micro-agglomerated asphaltenes), iron rust and other oxidative corrosion solids, fine bulk metal particles, paint or surface coating particles, plastic or polymeric or elastomer or rubber particles (e.g. resulting from the degradation of gaskets, valve parts, etc. . . . ), catalyst fines, ceramic or mineral particles, sand, clay, and other earthen particles, bacteria and other biologically generated solids, and mixtures of these that may be present as suspended particles, but otherwise don&#39;t detract from the merchantable quality of the Heavy Marine Fuel Composition as an ISO 8217 (2017) Table 2 compliant heavy (residual) marine fuel. 
     The blending of Product HMFO and Diluent Materials can be optimized using well known techniques and processes to maximize the commercial value of the Product HMFO as a low sulfur heavy (residual) marine fuel. That is the blend must be suitable for the intended use as heavy marine bunker fuel and generally be fungible as a bunker fuel for ocean going ships, but may contain “filler” hydrocarbons to bulk up the volume at minimal cost, a practice well known to a skilled person in the art of residual marine fuel blending and trading. Preferably the Heavy Marine Fuel Composition must retain the properties required of an ISO 8217 (2017) Table 2 compliant residual marine fuel and a sulfur content lower than the global MARPOL standard of 0.5% wt. sulfur (ISO 14596 or ISO 8754) so that the material qualifies as MARPOL Annex VI Low Sulfur Heavy Marine Fuel Oil (LS-HMFO). The disclosed process can lower the sulfur content of the Product HMFO to be lower than 0.5% wt. (i.e. below 0.1% wt sulfur (ISO 14596 or ISO 8754)) to qualify as a MARPOL Annex VI compliant Ultra-Low Sulfur Heavy Marine Fuel Oil (ULS-HMFO) and a Heavy Marine Fuel Composition likewise can be formulated to qualify as a MARPOL Annex VI compliant ULS-HMFO suitable for use as marine bunker fuel in the ECA zones by optimized blending. Regardless to qualify as an ISO 8217 (2017) Table 2 compliant residual marine fuel, the Heavy Marine Fuel Composition of the present invention must meet those internationally accepted standards. 
     Production Plant Description: Turning now to a more detailed illustrative embodiment of a production plant implementing both the core process and the DSRU disclosed,  FIG.  4    show a schematic for a production plant implementing the core process described above combined with a pre-DSRU ( FIG.  4   , item  2 ) which will reduce Detrimental Solids in a Feedstock HMFO to produce a Product HMFO that is ISO 8217 (2017) Table 2 compliant and with the desired properties of a low Detrimental Solids content. 
     It will be appreciated by one of skill in the art that additional alternative embodiments for the core process and the DSRU may involve multiple vessels and reactors even though only one of each is shown. Variations using multiple vessels/reactors are contemplated by the present invention but are not illustrated in greater detail for simplicity sake. 
     The Reactor System ( 11 ) for the core process is described in greater detail below and using multiple vessels process has been described. It will be noted by one of skill in the art that in  FIGS.  4  and  5   , portions of the production plant with similar function and operation have been assigned the same reference number. This has been done for convenience and succinctness only and differences between  FIG.  4    are duly noted and explained below. 
     The Feedstock HMFO (A) is fed from outside the battery limits (OSBL) to the Oil Feed Surge Drum ( 1 ) that receives feed from outside the battery limits (OSBL) and provides surge volume adequate to ensure smooth operation of the unit. Water entrained in the feed is removed from the HMFO with the water being discharged a stream ( 1   c ) for treatment OSBL. 
     As shown in  FIG.  4   , the Feedstock HMFO (A) is withdrawn from the Oil Feed Surge Drum ( 1 ) via line ( 1   b ) by the Oil Feed Pump ( 3 ) and sent to the DSRU ( 2 ) as a pretreatment step. The pre-treated Feedstock HMFO is pressurized to a pressure required for the process. The pressurized HMFO (A′) then passes through line ( 3   a ) to the Oil Feed/Product Heat Exchanger ( 5 ) where the pressurized HMFO (A′) is partially heated by the Product HMFO (B). The pressurized Feedstock HMFO (A′) passing through line ( 5   a ) is further heated against the effluent from the Reactor System (E) in the Reactor Feed/Effluent Heat Exchanger ( 7 ). 
     The heated and pressurized Feedstock HMFO (A″) in line ( 7   a ) is then mixed with Activating Gas (C) provided via line ( 23   c ) at Mixing Point (X) to form a Feedstock Mixture (D). The mixing point (X) can be any well know gas/liquid mixing system or entrainment mechanism well known to one skilled in the art. 
     The Feedstock Mixture (D) passes through line ( 9   a ) to the Reactor Feed Furnace ( 9 ) where the Feedstock Mixture (D) is heated to the specified process temperature. The Reactor Feed Furnace ( 9 ) may be a fired heater furnace or any other kind to type of heater as known to one of skill in the art if it will raise the temperature of the Feedstock mixture to the desired temperature for the process conditions. 
     The heated Feedstock Mixture (D′) exits the Reactor Feed Furnace ( 9 ) via line  9   b  and is fed into the Reactor System ( 11 ). The heated Feedstock Mixture (D′) enters the Reactor System ( 11 ) where environmental contaminates, such a sulfur, nitrogen, and metals are preferentially removed from the Feedstock HMFO component of the heated Feedstock Mixture. The Reactor System contains a catalyst which preferentially removes the sulfur compounds in the Feedstock HMFO component by reacting them with hydrogen in the Activating Gas to form hydrogen sulfide. The Reactor System will also achieve demetallization, denitrogenation, and a certain amount of ring opening hydrogenation of the complex aromatics and asphaltenes, however minimal hydrocracking of hydrocarbons should take place. The process conditions of hydrogen partial pressure, reaction pressure, temperature and residence time as measured by Liquid hourly velocity are optimized to achieve desired final product quality. A more detailed discussion of the Reactor System, the catalyst, the process conditions, and other aspects of the process are contained below in the “Reactor System Description.” 
     The Reactor System Effluent (E) exits the Reactor System ( 11 ) via line ( 11   a ) and exchanges heat against the pressurized and partially heats the Feedstock HMFO (A′) in the Reactor Feed/Effluent Exchanger ( 7 ). The partially cooled Reactor System Effluent (E′) then flows via line ( 11   c ) to the Hot Separator ( 13 ). 
     The Hot Separator ( 13 ) separates the gaseous components of the Reactor System Effluent (F) which are directed to line ( 13   a ) from the liquid components of the Reactor System effluent (G) which are directed to line ( 13   b ). The gaseous components of the Reactor System effluent in line ( 13   a ) are cooled against air in the Hot Separator Vapor Air Cooler ( 15 ) and then flow via line ( 15   a ) to the Cold Separator ( 17 ). 
     The Cold Separator ( 17 ) further separates any remaining gaseous components from the liquid components in the cooled gaseous components of the Reactor System Effluent (F′). The gaseous components from the Cold Separator (F″) are directed to line ( 17   a ) and fed onto the Amine Absorber ( 21 ). The Cold Separator ( 17 ) also separates any remaining Cold Separator hydrocarbon liquids (H) in line ( 17   b ) from any Cold Separator condensed liquid water (I). The Cold Separator condensed liquid water (I) is sent OSBL via line ( 17   c ) for treatment. 
     The hydrocarbon liquid components of the Reactor System effluent from the Hot Separator (G) in line ( 13   b ) and the Cold Separator hydrocarbon liquids (H) in line ( 17   b ) are combined and are fed to the Oil Product Stripper System ( 19 ). The Oil Product Stripper System ( 19 ) removes any residual hydrogen and hydrogen sulfide from the Product HMFO (B) which is discharged in line ( 19   b ) to storage OSBL. It is also contemplated that a second draw (not shown) may be included to withdraw a distillate product, preferably a middle to heavy distillate. The vent stream (M) from the Oil Product Stripper in line ( 19   a ) may be sent to the fuel gas system or to the flare system that are OSBL. 
     An alternative embodiment not shown in  FIG.  5   , but well within the skill of one in the art, would be to relocate the DSRU ( 18 ) from the line prior to the Oil Product Stripper ( 19 ) to a location downstream of the Oil Product Stripper ( 19 ). Such a relocation of the DSRU ( 18 ) to line ( 19   b ) will allow for the Detrimental Solids removal from the Product HMFO prior to being sent to storage OSBL. This location is practicable because the DSRU enhances the value of the Product HMFO without adversely impacting the desirable properties of the Product HMFO. The DRSU may also impart an additional amount of stability to the Product HMFO by removing the micron sized solids that may promote the formation of asphaltene solids or paraffinic solids. 
     The gaseous components from the Cold Separator (F″) in line ( 17   a ) contain a mixture of hydrogen, hydrogen sulfide and light hydrocarbons (mostly methane and ethane). This vapor stream ( 17   a ) feeds an Amine Absorber ( 21 ) where it is contacted against Lean Amine (J) provided OSBL via line ( 21   a ) to the Amine Absorber ( 21 ) to remove hydrogen sulfide from the gases making up the Activating Gas recycle stream (C′). Rich amine (K) which has absorbed hydrogen sulfide exits the bottom of the Amine Absorber ( 21 ) and is sent OSBL via line ( 21   b ) for amine regeneration and sulfur recovery. 
     The Amine Absorber overhead vapor in line ( 21   c ) is preferably recycled to the process as a Recycle Activating Gas (C′) via the Recycle Compressor ( 23 ) and line ( 23   a ) where it is mixed with the Makeup Activating Gas (C″) provided OSBL by line ( 23   b ). This mixture of Recycle Activating Gas (C′) and Makeup Activating Gas (C″) to form the Activating Gas (C) utilized in the process via line ( 23   c ) as noted above. A Scrubbed Purge Gas stream (H) is taken from the Amine Absorber overhead vapor line ( 21   c ) and sent via line ( 21   d ) to OSBL to prevent the buildup of light hydrocarbons or other non-condensables. 
     Reactor System Description: The core process Reactor System ( 11 ) illustrated in  FIG.  4    comprises a single reactor vessel loaded with the process catalyst and sufficient controls, valves and sensors as one of skill in the art would readily appreciate. 
     Alternative Reactor Systems in which more than one reactor vessel may be utilized in parallel or in a cascading series can easily be substituted for the single reactor vessel Reactor System  11  shown. In such an embodiment, each reactor vessel is similarly loaded with process catalyst and can be provided the heated Feed Mixture (D′) via a common line. The effluent from each of the three reactors is recombined in line and forms a combined Reactor Effluent (E) for further processing as described above. The illustrated arrangement will allow the three reactors to carry out the process effectively multiplying the hydraulic capacity of the overall Reactor System. Control valves and isolation valves may also prevent feed from entering one reactor vessel but not another reactor vessel. In this way one reactor can be by-passed and placed off-line for maintenance and reloading of catalyst while the remaining reactors continues to receive heated Feedstock Mixture (D′). It will be appreciated by one of skill in the art this arrangement of reactor vessels in parallel is not limited in number to three, but multiple additional reactor vessels can be added. The only limitation to the number of parallel reactor vessels is plot spacing and the ability to provide heated Feedstock Mixture (D′) to each active reactor. 
     In another illustrative embodiment cascading reactor vessels are loaded with process catalyst with the same or different activities toward metals, sulfur or other environmental contaminates to be removed. For example, one reactor may be loaded with a highly active demetallization catalyst, a second subsequent or downstream reactor may be loaded with a balanced demetallization/desulfurizing catalyst, and reactor downstream from the second reactor may be loaded with a highly active desulfurization catalyst. This allows for greater control and balance in process conditions (temperature, pressure, space flow velocity, etc. . . . ) so it is tailored for each catalyst. In this way one can optimize the parameters in each reactor depending upon the material being fed to that specific reactor/catalyst combination and minimize the hydrocracking reactions. As with the prior illustrative embodiment, multiple cascading series of reactors can be utilized in parallel and in this way the benefits of such an arrangement noted above (i.e. allow one series to be “online” while the other series is “off line” for maintenance or allow increased plant capacity). 
     The reactor(s) that form the Reactor System may be fixed bed, ebulliated bed or slurry bed or a combination. As envisioned, fixed bed reactors are preferred as these are easier to operate and maintain. 
     The reactor vessel in the Reactor System is loaded with one or more process catalysts. The exact design of the process catalyst system is a function of feedstock properties, product requirements and operating constraints and optimization of the process catalyst can be carried out by routine trial and error by one of ordinary skill in the art. 
     The process catalyst(s) comprise at least one metal selected from the group consisting of the metals each belonging to the groups 6, 8, 9 and 10 of the Periodic Table, and more preferably a mixed transition metal catalyst such as Ni—Mo, Co—Mo, Ni—W or Ni—Co—Mo are utilized. The metal is preferably supported on a porous inorganic oxide catalyst carrier. The porous inorganic oxide catalyst carrier is at least one carrier selected from the group consisting of alumina, alumina/boria carrier, a carrier containing metal-containing aluminosilicate, alumina/phosphorus carrier, alumina/alkaline earth metal compound carrier, alumina/titania carrier and alumina/zirconia carrier. The preferred porous inorganic oxide catalyst carrier is alumina. The pore size and metal loadings on the carrier may be systematically varied and tested with the desired feedstock and process conditions to optimize the properties of the Product HMFO. Such activities are well known and routine to one of skill in the art. Catalyst in the fixed bed reactor(s) may be dense-loaded or sock-loaded. 
     The catalyst selection utilized within and for loading the Reactor System may be preferential to desulfurization by designing a catalyst loading scheme that results in the Feedstock mixture first contacting a catalyst bed that with a catalyst preferential to demetallization followed downstream by a bed of catalyst with mixed activity for demetallization and desulfurization followed downstream by a catalyst bed with high desulfurization activity. In effect the first bed with high demetallization activity acts as a guard bed for the desulfurization bed. 
     The objective of the Reactor System is to treat the Feedstock HMFO at the severity required to meet the Product HMFO specification. Demetallization, denitrogenation and hydrocarbon hydrogenation reactions may also occur to some extent when the process conditions are optimized so performing the Reactor System achieves the required level of desulfurization. Hydrocracking is preferably minimized to reduce the volume of hydrocarbons formed as by-product hydrocarbons to the process. The objective of the process is to selectively remove the environmental contaminates from Feedstock HMFO and minimize the formation of unnecessary by-product hydrocarbons (C1-C8 hydrocarbons). 
     The process reactive conditions in each reactor vessel will depend upon the feedstock, the catalyst utilized and the desired final properties of the Product HMFO desired. Variations in reactive conditions are to be expected by one of ordinary skill in the art and these may be determined by pilot plant testing and systematic optimization of the process. With this in mind it has been found that the operating pressure, the indicated operating temperature, the ratio of the Activating Gas to Feedstock HMFO, the partial pressure of hydrogen in the Activating Gas and the space velocity all are important parameters to consider. The operating pressure of the Reactor System should be in the range of 250 psig and 3000 psig, preferably between 1000 psig and 2500 psig and more preferably between 1500 psig and 2200 psig. The indicated operating temperature of the Reactor System should be 500° F. to 900° F., preferably between 650° F. and 850° F. and more preferably between 680° F. and 800° F. The ratio of the quantity of the Activating Gas to the quantity of Feedstock HMFO should be in the range of 250 scf gas/bbl of Feedstock HMFO to 10,000 scf gas/bbl of Feedstock HMFO, preferably between 2000 scf gas/bbl of Feedstock HMFO to 5000 scf gas/bbl of Feedstock HMFO and more preferably between 2500 scf gas/bbl of Feedstock HMFO to 4500 scf gas/bbl of Feedstock HMFO. The Activating Gas should be selected from mixtures of nitrogen, hydrogen, carbon dioxide, gaseous water, and methane, so Activating Gas has an ideal gas partial pressure of hydrogen (pH2) greater than 80% of the total pressure of the Activating Gas mixture (P) and preferably wherein the Activating Gas has an ideal gas partial pressure of hydrogen (pH2) greater than 95% of the total pressure of the Activating Gas mixture (P). The Activating Gas may have a hydrogen mole fraction in the range between 80% of the total moles of Activating Gas mixture and more preferably wherein the Activating Gas has a hydrogen mole fraction between 80% and 99% of the total moles of Activating Gas mixture. The liquid hourly space velocity within the Reactor System should be between 0.05 and 1.0 h 1 ; preferably between 0.08 h 1  and 0.5 h 1  and more preferably between 0.1 h 1  and 0.3 h 1  to achieve deep desulfurization with product sulfur levels below 0.1 ppmw. 
     The hydraulic capacity rate of the Reactor System should be between 100 bbl of Feedstock HMFO/day and 100,000 bbl of Feedstock HMFO/day, preferably between 1000 bbl of Feedstock HMFO/day and 60,000 bbl of Feedstock HMFO/day, more preferably between 5,000 bbl of Feedstock HMFO/day and 45,000 bbl of Feedstock HMFO/day, and even more preferably between 10,000 bbl of Feedstock HMFO/day and 30,000 bbl of Feedstock HMFO/day. The desired hydraulic capacity may be achieved in a single reactor vessel Reactor System or in a multiple reactor vessel Reactor System. 
     These examples will provide one skilled in the art with a more specific illustrative embodiment for conducting the process disclosed and claimed herein: 
     Example 1 
     Overview: The purpose of a pilot test run is to demonstrate that Feedstock HMFO can be processed through a reactor loaded with commercially available catalysts at specified conditions to remove environmental contaminates, specifically sulfur and other contaminants from the Feedstock HMFO to produce a Product HMFO that is MARPOL compliant, that is production of a Low Sulfur Heavy Marine Fuel Oil (LS-HMFO) or Ultra-Low Sulfur Heavy Marine Fuel Oil (USL-HMFO). 
     Pilot Unit Set Up: The pilot unit will be set up with two 434 cm 3  reactors arranged in series to process the Feedstock HMFO. The lead reactor will be loaded with a blend of a commercially available hydrodemetaling (HDM) catalyst and a commercially available hydrotransition (HDT) catalyst. One of skill in the art will appreciate that the HDT catalyst layer may be formed and optimized using a mixture of HDM and HDS catalysts combined with an inert material to achieve the desired intermediate/transition activity levels. The second reactor will be loaded with a blend of the commercially available hydro-transition (HDT) and a commercially available hydrodesulfurization (HDS). One can load the second reactor simply with a commercially hydrodesulfurization (HDS) catalyst. One of skill in the art will appreciate that the specific feed properties of the Feedstock HMFO may affect the proportion of HDM, HDT and HDS catalysts in the reactor system. A systematic process of testing different combinations with the same feed will yield the optimized catalyst combination for any feedstock and reaction conditions. For this example, the first reactor will be loaded with ⅔ hydro-demetaling catalyst and ⅓ hydro-transition catalyst. The second reactor will be loaded with all hydrodesulfurization catalyst. The catalysts in each reactor will be mixed with glass beads (approximately 50% by volume) to improve liquid distribution and better control reactor temperature. For this pilot test run, one should use these commercially available catalysts: HDM: Albemarle KFR 20 series or equivalent; HDT: Albemarle KFR 30 series or equivalent; HDS: Albemarle KFR 50 or KFR 70 or equivalent. Once set up of the pilot unit is complete, the catalyst can be activated by sulfiding the catalyst using dimethyldisulfide (DMDS) in a manner well known to one of skill in the art. 
     Pilot Unit Operation: Upon completion of the activating step, the pilot unit will be ready to receive the Feedstock HMFO and Activating Gas feed. For the present example, the Activating Gas can be technical grade or better hydrogen gas. The mixed Feedstock HMFO and Activating Gas will be provided to the pilot plant at rates and operating conditions as specified: Oil Feed Rate: 108.5 ml/h (space velocity=0.25/h); Hydrogen/Oil Ratio: 570 Nm3/m3 (3200 scf/bbl); Reactor Temperature: 372° C. (702° F.); Reactor Outlet Pressure: 13.8 MPa(g) (2000 psig). 
     One of skill in the art will know that the rates and conditions may be systematically adjusted and optimized depending upon feed properties to achieve the desired product requirements. The unit will be brought to a steady state for each condition and full samples taken so analytical tests can be completed. Material balance for each condition should be closed before moving to the next condition. 
     Expected impacts on the Feedstock HMFO properties are: Sulfur Content (wt %): Reduced by at least 80%; Metals Content (wt %): Reduced by at least 80%; MCR/Asphaltene Content (wt %): Reduced by at least 30%; Nitrogen Content (wt %): Reduced by at least 20%; C1-Naphtha Yield (wt %): Not over 3.0% and preferably not over 1.0%. 
     Process conditions in the Pilot Unit can be systematically adjusted as per Table 1 to assess the impact of process conditions and optimize the performance of the process for the specific catalyst and Feedstock HMFO utilized. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Optimization of Process Conditions 
               
            
           
           
               
               
               
               
               
            
               
                   
                 HC Feed Rate 
                   
                   
                   
               
               
                   
                 (ml/h), 
                 Nm 3  H 2 /m 3  oil/ 
                 Temp 
                 Pressure 
               
               
                 Case 
                 [LHSV(/h)] 
                 scf H 2 /bbl oil 
                 (° C./° F.) 
                 (MPa(g)/psig) 
               
               
                   
               
               
                 Baseline 
                 108.5 [0.25] 
                 570/3200 
                 372/702 
                 13.8/2000 
               
               
                 T1 
                 108.5 [0.25] 
                 570/3200 
                 362/684 
                 13.8/2000 
               
               
                 T2 
                 108.5 [0.25] 
                 570/3200 
                 382/720 
                 13.8/2000 
               
               
                 L1 
                 130.2 [0.30] 
                 570/3200 
                 372/702 
                 13.8/2000 
               
               
                 L2 
                 86.8 [0.20] 
                 570/3200 
                 372/702 
                 13.8/2000 
               
               
                 H1 
                 108.5 [0.25] 
                 500/2810 
                 372/702 
                 13.8/2000 
               
               
                 H2 
                 108.5 [0.25] 
                 640/3590 
                 372/702 
                 13.8/2000 
               
               
                 S1 
                 65.1 [0.15] 
                 620/3480 
                 385/725 
                 15.2/2200 
               
               
                   
               
            
           
         
       
     
     In this way, the conditions of the pilot unit can be optimized to achieve less than 0.5% wt. sulfur Product HMFO and preferably a 0.1% wt. sulfur Product HMFO. Conditions for producing ULS-HMFO (i.e. 0.1% wt. sulfur Product HMFO) will be: Feedstock HMFO Feed Rate: 65.1 ml/h (space velocity=0.15/h); Hydrogen/Oil Ratio: 620 Nm 3 /m 3  (3480 scf/bbl); Reactor Temperature: 385° C. (725° F.); Reactor Outlet Pressure: 15 MPa(g) (2200 psig) 
     Table 2 summarizes the anticipated impacts on key properties of HMFO 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Expected Impact of Process on Key Properties of HMFO 
               
            
           
           
               
               
               
               
            
               
                 Property 
                 Minimum 
                 Typical 
                 Maximum 
               
               
                   
               
               
                 Sulfur Conversion/Removal 
                  80% 
                  90% 
                   98% 
               
               
                 Metals Conversion/Removal 
                  80% 
                  90% 
                  100% 
               
               
                 MCR Reduction 
                  30% 
                  50% 
                   70% 
               
               
                 Asphaltene Reduction 
                  30% 
                  50% 
                   70% 
               
               
                 Nitrogen Conversion 
                  10% 
                  30% 
                   70% 
               
               
                 C1 through Naphtha Yield 
                 0.5% 
                 1.0% 
                  4.0% 
               
               
                 Hydrogen Consumption (scf/bbl) 
                 500 
                 750 
                 1500 
               
               
                   
               
            
           
         
       
     
     Table 3 lists analytical tests to be carried out for the characterization of the Feedstock HMFO and Product HMFO. The analytical tests include those required by ISO for the Feedstock HMFO and the Product HMFO to qualify and trade in commerce as ISO compliant residual marine fuels. The additional parameters are provided so that one skilled in the art can understand and appreciate the effectiveness of the inventive process. 
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Analytical Tests and Testing Procedures 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Sulfur Content 
                 ISO 8754 or ISO 14596 or ASTM  
               
               
                   
                   
                 D4294 
               
               
                   
                 Density @ 15° C. 
                 ISO 3675 or ISO 12185 
               
               
                   
                 Kinematic Viscosity @ 50° C. 
                 ISO 3104 
               
               
                   
                 Pour Point, ° C. 
                 ISO 3016 
               
               
                   
                 Flash Point, ° C. 
                 ISO 2719 
               
               
                   
                 CCAI 
                 ISO 8217, ANNEX B 
               
               
                   
                 Ash Content 
                 ISO 6245 
               
               
                   
                 Total Sediment-Aged 
                 ISO 10307-2 
               
               
                   
                 Micro Carbon Residue, mass % 
                 ISO 10370 
               
               
                   
                 H2S, mg/kg 
                 IP 570 
               
               
                   
                 Acid Number 
                 ASTM D664 
               
               
                   
                 Water 
                 ISO 3733 
               
               
                   
                 Specific Contaminants 
                 IP 501 or IP 470 (unless indicated  
               
               
                   
                   
                 otherwise) 
               
               
                   
                 Vanadium 
                 or ISO 14597 
               
               
                   
                 Sodium 
                   
               
               
                   
                 Aluminum 
                 or ISO 10478 
               
               
                   
                 Silicon 
                 or ISO 10478 
               
               
                   
                 Calcium 
                 or IP 500 
               
               
                   
                 Zinc 
                 or IP 500 
               
               
                   
                 Phosphorous 
                 IP 500 
               
               
                   
                 Nickle 
                   
               
               
                   
                 Iron 
                   
               
               
                   
                 Distillation 
                 ASTM D7169 
               
               
                   
                 C:H Ratio 
                 ASTM D3178 
               
               
                   
                 SARA Analysis 
                 ASTM D2007 
               
               
                   
                 Asphaltenes, wt % 
                 ASTM D6560 
               
               
                   
                 Total Nitrogen 
                 ASTM D5762 
               
               
                   
                 Vent Gas Component Analysis 
                 FID Gas Chromatography or  
               
               
                   
                   
                 comparable 
               
               
                   
                   
               
            
           
         
       
     
     Table 4 contains the Feedstock HMFO analytical test results and the Product HMFO analytical test results expected from the inventive process that indicates 0the production of a LS HMFO. It will be noted by one of skill in the art that under the conditions, the levels of hydrocarbon cracking will be minimized to levels substantially lower than 10%, more preferably less than 5% and even more preferably less than 1% of the total mass balance. Also noted this process achieves minimal hydrocracking to low boiling fractions (naphtha less than 150° C.; and light diesel (less than 250° C.), as well as a conversion of 520° C. materials of less than 30%. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Analytical Results 
               
            
           
           
               
               
               
            
               
                   
                 Feedstock HMFO 
                 Product HMFO 
               
               
                   
               
            
           
           
               
               
               
            
               
                 Sulfur Content, mass % 
                 3.0 
                 0.3 
               
               
                 Density @ 15 C., kg/m 3   
                 990 
                 950  (1)   
               
               
                 Kinematic Viscosity @ 50 C., mm 2 /s 
                 380 
                 100  (1)   
               
               
                 Pour Point, ° C. 
                 20 
                 10 
               
               
                 Flash Point, ° C. 
                 110 
                 100  (1)   
               
               
                 CCAI 
                 850 
                 820 
               
               
                 Ash Content, mass % 
                 0.1 
                 0.0 
               
               
                 Total Sediment-Aged, mass % 
                 0.1 
                 0.0 
               
               
                 Micro Carbon Residue, mass % 
                 13.0 
                 6.5 
               
               
                 H2S, mg/kg 
                 0 
                 0 
               
               
                 Acid Number, mg KO/g 
                 1 
                 0.5 
               
               
                 Water, vol % 
                 0.5 
                 0 
               
               
                 Specific Contaminants, mg/kg 
                   
                   
               
               
                 Vanadium 
                 180 
                 20 
               
               
                 Sodium 
                 30 
                 1 
               
               
                 Aluminum 
                 10 
                 1 
               
               
                 Silicon 
                 30 
                 3 
               
               
                 Calcium 
                 15 
                 1 
               
               
                 Zinc 
                 7 
                 1 
               
               
                 Phosphorous 
                 2 
                 0 
               
               
                 Nickle 
                 40 
                 5 
               
               
                 Iron 
                 20 
                 2 
               
               
                 Distillation, ° C./° F. 
                   
                   
               
               
                 IBP 
                 160/320 
                 120/248 
               
               
                 5% wt 
                 235/455 
                 225/437 
               
               
                 10% wt 
                 290/554 
                 270/518 
               
               
                 30% wt 
                 410/770 
                 370/698 
               
               
                 50% wt 
                 540/1004 
                 470/878 
               
               
                 70% wt 
                 650/1202 
                 580/1076 
               
               
                 90% wt 
                 735/1355 
                 660/1220 
               
               
                 FBP 
                 820/1508 
                 730/1346 
               
               
                 C:H Ratio (ASTM D3178) 
                 1.2 
                 1.3 
               
               
                 SARA Analysis 
                   
                   
               
               
                 Saturates 
                 16 
                 22 
               
               
                 Aromatics 
                 50 
                 50 
               
               
                 Resins 
                 28 
                 25 
               
               
                 Asphaltenes 
                 6 
                 3 
               
               
                 Asphaltenes, wt % 
                 6.0 
                 2.5 
               
               
                 Total Nitrogen, mg/kg 
                 4000 
                 3000 
               
               
                   
               
               
                 Note: 
               
               
                   (1)  property will be adjusted to a higher value by post process removal of light material via distillation or stripping from Product HMFO. 
               
            
           
         
       
     
     The Product HMFO produced by the inventive process will reach ULS HMFO limits (i.e. 0.1% wt. sulfur Product HMFO) by systematic variation of the process parameters, for example by a lower space velocity or by using a Feedstock HMFO with a lower initial sulfur content. 
     Example 2: RMG-380 HMFO 
     Pilot Unit Set Up: A pilot unit was set up as noted above in Example 1 with these changes: the first reactor was loaded with: as the first (upper) layer encountered by the feedstock 70% vol Albemarle KFR 20 series hydro-demetaling catalyst and 30% vol Albemarle KFR 30 series hydro-transition catalyst as the second (lower) layer. The second reactor was loaded with 20% Albemarle KFR 30 series hydrotransition catalyst as the first (upper) layer and 80% vol hydrodesulfurization catalyst as the second (lower) layer. The catalyst was activated by sulfiding the catalyst with dimethyldisulfide (DMDS) in a manner well known to one of skill in the art. 
     Pilot Unit Operation: Upon completion of the activating step, the pilot unit was ready to receive the Feedstock HMFO and Activating Gas feed. The Activating Gas was technical grade or better hydrogen gas. The Feedstock HMFO was a commercially available ISO 8217 (2017) Table 2 compliant HMFO, except for a high sulfur content (2.9 wt %). The mixed Feedstock HMFO and Activating Gas was provided to the pilot plant at rates and conditions as specified in Table 5 below. The conditions were varied to optimize the level of sulfur in the Product HMFO material. 
     
       
         
           
               
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Process Conditions 
                 Product 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 HC Feed 
                   
                   
                 Pressure 
                 HMFO 
               
               
                   
                 Rate (ml/h), 
                 Nm 3  H 2 /m 3  oil/ 
                 Temp 
                 (MPa(g)/ 
                 Sulfur 
               
               
                 Case 
                 [LHSV(/h)] 
                 scf H 2 /bbl oil 
                 (° C. /° F.) 
                 psig) 
                 % wt. 
               
               
                   
               
               
                 Baseline 
                 108.5 [0.25] 
                 570/3200 
                 371/700 
                 13.8/2000 
                 0.24 
               
               
                 T1 
                 108.5 [0.25] 
                 570/3200 
                 362/684 
                 13.8/2000 
                 0.53 
               
               
                 T2 
                 108.5 [0.25] 
                 570/3200 
                 382/720 
                 13.8/2000 
                 0.15 
               
               
                 L1 
                 130.2 [0.30] 
                 570/3200 
                 372/702 
                 13.8/2000 
                 0.53 
               
               
                 S1 
                 65.1 [0.15] 
                 620/3480 
                 385/725 
                 15.2/2200 
                 0.10 
               
               
                 P1 
                 108.5 [0.25] 
                 570/3200 
                 371/700 
                 /1700 
                 0.56 
               
               
                 T2/P1 
                 108.5 [0.25] 
                 570/3200 
                 382/720 
                 /1700 
                 0.46 
               
               
                   
               
            
           
         
       
     
     Analytical data for a representative sample of the Feedstock HMFO and representative samples of Product HMFO are below: 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Analytical Results-HMFO (RMG-380) 
               
            
           
           
               
               
               
               
            
               
                   
                 Feedstock 
                 Product 
                 Product 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 Sulfur Content, mass % 
                 2.9 
                 0.3 
                 0.1 
               
               
                 Density @ 15° C., kg/m 3   
                 988 
                 932 
                 927 
               
               
                 Kinematic Viscosity @ 50° C., mm 2 /s 
                 382 
                 74 
                 47 
               
               
                 Pour Point, ° C. 
                 −3 
                 −12 
                 −30 
               
               
                 Flash Point, ° C. 
                 116 
                 96 
                 90 
               
               
                 CCAI 
                 850 
                 812 
                 814 
               
               
                 Ash Content, mass % 
                 0.05 
                 0.0 
                 0.0 
               
               
                 Total Sediment-Aged, mass % 
                 0.04 
                 0.0 
                 0.0 
               
               
                 Micro Carbon Residue, mass % 
                 11.5 
                 3.3 
                 4.1 
               
               
                 H2S, mg/kg 
                 0.6 
                 0 
                 0 
               
               
                 Acid Number, mg KO/g 
                 0.3 
                 0.1 
                 &gt;0.05 
               
               
                 Water, vol % 
                 0 
                 0.0 
                 0.0 
               
               
                 Specific Contaminants, mg/kg 
                   
                   
                   
               
               
                 Vanadium 
                 138 
                 15 
                 &lt;1 
               
               
                 Sodium 
                 25 
                 5 
                 2 
               
               
                 Aluminum 
                 21 
                 2 
                 &lt;1 
               
               
                 Silicon 
                 16 
                 3 
                 1 
               
               
                 Calcium 
                 6 
                 2 
                 &lt;1 
               
               
                 Zinc 
                 5 
                 &lt;1 
                 &lt;1 
               
               
                 Phosphorous 
                 &lt;1 
                 2 
                 1 
               
               
                 Nickle 
                 33 
                 23 
                 2 
               
               
                 Iron 
                 24 
                 8 
                 1 
               
               
                 Distillation, ° C./° F. 
                   
                   
                   
               
               
                 IBP 
                 178/352 
                 168/334 
                 161/322 
               
               
                 5% wt 
                 258/496 
                 235/455 
                 230/446 
               
               
                 10% wt 
                 298/569 
                 270/518 
                 264/507 
               
               
                 30% wt 
                 395/743 
                 360/680 
                 351/664 
               
               
                 50% wt 
                 517/962 
                 461/862 
                 439/822 
               
               
                 70% wt 
                 633/1172 
                 572/1062 
                 552/1026 
               
               
                 90% wt 
                 &gt;720/&gt;1328 
                 694/1281 
                 679/1254 
               
               
                 FBP 
                 &gt;720/&gt;1328 
                 &gt;720/ 
                 &gt;720/ 
               
               
                   
                   
                 &gt;1328 
                 &gt;1328 
               
               
                 C:H Ratio (ASTM D3178) 
                 1.2 
                 1.3 
                 1.3 
               
               
                 SARA Analysis 
                   
                   
                   
               
               
                 Saturates 
                 25.2 
                 28.4 
                 29.4 
               
               
                 Aromatics 
                 50.2 
                 61.0 
                 62.7 
               
               
                 Resins 
                 18.6 
                 6.0 
                 5.8 
               
               
                 Asphaltenes 
                 6.0 
                 4.6 
                 2.1 
               
               
                 Asphaltenes, wt % 
                 6.0 
                 4.6 
                 2.1 
               
               
                 Total Nitrogen, mg/kg 
                 3300 
                 1700 
                 1600 
               
               
                   
               
            
           
         
       
     
     In Table 6, both Feedstock HMFO and Product HMFO exhibited properties consistent with ISO 8217 (2017) Table 2 for a residual marine fuel, except that the sulfur content of the Product HMFO was reduced as noted above when compared to the Feedstock HMFO. 
     One of skill in the art will appreciate that the above Product HMFO produced by the inventive process has achieved not only an ISO 8217 (2017) Table 2 compliant LS HMFO (i.e. 0.5% wt. sulfur) but also an ISO 8217 (2017) Table 2 compliant ULS HMFO limits (i.e. 0.1% wt. sulfur) Product HMFO. Further it will be noted that the conversion rate for product “B” and product “C” is less than 30% in both cases, slightly less than 17% and less than 25% respectfully. 
     Example 3: RMK-500 HMFO 
     The feedstock to the pilot reactor utilized in example 2 above was changed to a commercially available and merchantable ISO 8217 (2017) RMK-500 compliant HMFO, except that it has high environmental contaminates (i.e. sulfur (3.3 wt %)). Other bulk characteristic of the RMK-500 feedstock high sulfur HMFO are provide below: 
     
       
         
           
               
             
               
                 TABLE 7 
               
               
                   
               
               
                 Analytical Results-Feedstock HMFO (RMK-500) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Sulfur Content, mass % 
                 3.3 
               
               
                   
                 Density @ 15° C., kg/m 3   
                 1006 
               
               
                   
                 Kinematic Viscosity @ 50° C., mm 2 /s 
                 500 
               
               
                   
                   
               
            
           
         
       
     
     The mixed Feedstock (RMK-500) HMFO and Activating Gas was provided to the pilot plant at rates and conditions and the resulting sulfur levels achieved in the table below 
     
       
         
           
               
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Process Conditions 
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 HC Feed  
                   
                   
                 Pressure 
                 Product 
               
               
                   
                 Rate (ml/h), 
                 Nm 3  H 2 /m 3  oil/ 
                 Temp 
                 (MPa(g)/ 
                 (RMK-500) 
               
               
                 Case 
                 [LHSV(/h)] 
                 scf H 2 /bbl oil 
                 (° C. /° F.) 
                 psig) 
                 sulfur % wt. 
               
               
                   
               
               
                 A 
                 108.5 [0.25] 
                 640/3600 
                 377/710 
                 13.8/2000 
                 0.57 
               
               
                 B 
                 95.5 [0.22] 
                 640/3600 
                 390/735 
                 13.8/2000 
                 0.41 
               
               
                 C 
                 95.5 [0.22] 
                 640/3600 
                 390/735 
                 11.7/1700 
                 0.44 
               
               
                 D 
                 95.5 [0.22] 
                 640/3600 
                 393/740 
                 10.3/1500 
                 0.61 
               
               
                 E 
                 95.5 [0.22] 
                 640/3600 
                 393/740 
                 17.2/2500 
                 0.37 
               
               
                 F 
                 95.5 [0.22] 
                 640/3600 
                 393/740 
                 8.3/1200 
                 0.70 
               
               
                 G 
                 95.5 [0.22] 
                 640/3600 
                 416/780 
                 8.3/1200 
               
               
                   
               
            
           
         
       
     
     The resulting product (RMK-500) HMFO exhibited observed bulk properties consistent with the feedstock (RMK-500) HMFO, except that the sulfur content was reduced as noted in the above table. 
     One of skill in the art will appreciate that the above Product HMFO produced by the inventive process has achieved a LS HMFO (i.e. 0.5% wt. sulfur) Product HMFO having bulk characteristics of a ISO 8217 (2017) Table 2 compliant RMK-500 residual fuel oil. It will also be appreciated that the process can be successfully carried out under non-hydrocracking conditions (i.e. lower temperature and pressure) that substantially reduce the hydrocracking of the feedstock material. When conditions were increased to much higher pressure (Example E) a product with a lower sulfur content was achieved, however some observed that there was an increase in light hydrocarbons and wild naphtha production. 
     This prophetic example will provide one skilled in the art with a more specific illustrative embodiment for conducting the processes disclosed: 
     Prophetic Example of DSRU Operation: To exemplify the invention, experiments can be carried out using a first porous sintered metal filter having a permeametric radii from 50-100 micron followed by a second porous sintered metal filter having a permeametric radii from 50-0.1 micron. Examples of such filter materials are commercially available in stainless steel and other alloy metals from Mott Corp and other suppliers. Suitable membrane filters may also be useful. A physical entrainment filter composed of a packed bed of particulate material such a deactivated alumina, silica and the like will also likely achieve the desired results. The removal of the Detrimental Solids is carried out by the physical entrainment or removal of the solids from the HMFO stream. 
     As part of the post Core Process treatment of the Product HMFO, the described process can be carried out to condition the Product HMFO for easier transport and handling, increased compatibility and stability when blended with other marine fuel materials (i.e. MGO or MDO), and enhance the value of these materials as low sulfur HMFO. 
     Table 9 contains the expected analytical test results for (A) Feedstock HMFO; (B) the Core Process Product HMFO and (C) Overall Process (Core+DSRU) from the inventive processes. These results will indicate to one of skill in the art that the production of a ULS HMFO can be achieved. It will be noted by one of skill in the art that under the conditions, the levels of hydrocarbon cracking will be minimized to levels substantially lower than 10%, more preferably less than 5% and even more preferably less than 1% of the total mass balance. Further it will be noted that the conversion rate for product “B” and product “C” is less than 30% in both cases. 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 Analytical Results 
               
            
           
           
               
               
               
               
            
               
                   
                 A 
                 B 
                 C 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 Sulfur Content, mass % 
                 3.0 
                 Less than 0.5 
                 Less than 0.1 
               
               
                 Density @ 15° C., kg/m 3   
                 990 
                 950  (1)   
                 950  (1)   
               
               
                 Kinematic Viscosity @ 50 
                 380 
                 100  (1)   
                 100  (1)   
               
               
                 ° C., mm 2 /s 
                   
                   
                   
               
               
                 Pour Point, ° C. 
                 20 
                 10 
                 10 
               
               
                 Flash Point, ° C. 
                 110 
                 100  (1)   
                 100  (1)   
               
               
                 CCAI 
                 850 
                 820 
                 820 
               
               
                 Ash Content, mass % 
                 0.1 
                 0.0 
                 0.0 
               
               
                 Total Sediment-Aged, 
                 0.1 
                 0.0 
                 0.0 
               
               
                 mass % 
                   
                   
                   
               
               
                 Micro Carbon Residue, 
                 13.0 
                 6.5 
                 6.5 
               
               
                 mass % 
                   
                   
                   
               
               
                 H2S, mg/kg 
                 0 
                 0 
                 0 
               
               
                 Acid Number, mg KO/g 
                 1 
                 0.5 
                 Less than 0.5 
               
               
                 Water, vol % 
                 0.5 
                 0 
                 0 
               
               
                 Specific Contaminants, mg/kg 
                   
                   
                   
               
               
                 Vanadium 
                 180 
                 20 
                 20 
               
               
                 Sodium 
                 30 
                 1 
                 1 
               
               
                 Aluminum 
                 10 
                 1 
                 1 
               
               
                 Silicon 
                 30 
                 3 
                 3 
               
               
                 Calcium 
                 15 
                 1 
                 1 
               
               
                 Zinc 
                 7 
                 1 
                 1 
               
               
                 Phosphorous 
                 2 
                 0 
                 0 
               
               
                 Nickle 
                 40 
                 5 
                 5 
               
               
                 Iron 
                 20 
                 2 
                 2 
               
               
                 Distillation, ° C./° F. 
                   
                   
                   
               
               
                 IBP 
                 160/320 
                 120/248 
                 120/248 
               
               
                 5% wt 
                 235/455 
                 225/437 
                 225/437 
               
               
                 10% wt 
                 290/554 
                 270/518 
                 270/518 
               
               
                 30% wt 
                 410/770 
                 370/698 
                 370/698 
               
               
                 50% wt 
                 540/1004 
                 470/878 
                 470/878 
               
               
                 70% wt 
                 650/1202 
                 580/1076 
                 580/1076 
               
               
                 90% wt 
                 735/1355 
                 660/1220 
                 660/1220 
               
               
                 FBP 
                 820/1508 
                 730/1346 
                 730/1346 
               
               
                 C:H Ratio (ASTM D3178) 
                 1.2 
                 1.3 
                 1.3 
               
               
                 SARA Analysis 
                   
                   
                   
               
               
                 Saturates 
                 16 
                 22 
                 22 
               
               
                 Aromatics 
                 50 
                 50 
                 50 
               
               
                 Resins 
                 28 
                 25 
                 25 
               
               
                 Asphaltenes 
                 6 
                 3 
                 3 
               
               
                 Asphaltenes, wt % 
                 6.0 
                 2.5 
                 2.5 
               
               
                 Total Nitrogen, mg/kg 
                 4000 
                 3000 
                 3000 
               
               
                   
               
               
                 Note: 
               
               
                   (1)  property will be adjusted to a higher value by post process removal of light material via distillation or stripping from Product HMFO. 
               
            
           
         
       
     
     One of skill in the art will know that the Aluminum and Silicon contaminates are directly correlated to the cat fines and other mineral solids present in the Feedstock HMFO. The primary source of these solids is the inclusion of FCC slurry oil as a component of the Feedstock HMFO, although other sources may also contribute to these contaminations. The low levels of Aluminum and Silicon are achieved in the Product HMFO and one of skill in the art will appreciate this indicates a significant reduction in the cat fines and other Detrimental Solids present in the Product HMFO. Further solids removal will be achieved with the post processing DSRU and it is expected that solids with a diameter in the range of 0.1 to 100 microns will be removed by the DSRU from the Product HMFO. 
     It will be appreciated by those skilled in the art that changes could be made to the illustrative embodiments described above without departing from the broad inventive concepts thereof. It is understood, therefore, that the inventive concepts disclosed are not limited to the illustrative embodiments or examples disclosed, but it is intended to cover modifications within the scope of the inventive concepts as defined by the claims.