Abstract:
Systems and methods for refining conventional crude and heavy, corrosive, contaminant-laden carbonaceous crude (Opportunity Crude) in partially or totally separated streams or trains.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 13/447,957, which is hereby incorporated by reference, and claims the priority of U.S. Provisional Patent Application Ser. No. 61/475,519, filed on Apr. 14, 2011, which is incorporated herein by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not applicable. 
       FIELD OF THE INVENTION 
       [0003]    The present invention generally relates to refining of corrosive crudes. More particularly, the invention relates to systems and methods for refining conventional crude and heavy, corrosive, contaminant-laden carbonaceous crude in partially separated streams or trains. 
       BACKGROUND OF THE INVENTION 
       [0004]    For existing oil refineries, the high cost of conventional, light sweet, crude oils has led refiners to consider retrofits with partial replacement of conventional crude oils with price-discounted heavy, corrosive (organic acids), contaminant laden (organic metals, polar heteroatoms, etc.) carbonaceous material more commonly referred to as “Opportunity Crude”, such as those offered from extensive reserves in Western Canada, Latin America, China, Russia, North Sea and elsewhere. 
         [0005]    Many refiners have performed such retrofits by co-mingling or blending Opportunity Crude with conventional crude and requiring extensive modifications to almost every refinery process unit to deal with changes in the unit feed composition (e.g., boiling range, molecular structure, etc.) and level of contaminants (e.g., metals, sulfur, nitrogen, organic acids, etc.). 
         [0006]    Declining markets for high sulfur fuel oil and asphalt, combined with shifting to heavier feedstock materials, have resulted in the need for heavy residual oil upgrading technologies, such as delayed coking, to reduce the yield of high sulfur fuel oil/asphalt and increase the yield of products in the range of liquid transportation fuels. 
         [0007]    The combination of extensive retrofit costs and inefficient application of heavy residual oil upgrading often leads to an extremely high project capital cost, which may not justify the investment decision to introduce the Opportunity Crude into an existing refinery. This situation is likely to continue for an extended period of time on a worldwide basis. 
         [0008]    A typical and conventional crude (e.g., low sulfur, low metals, low naphthenic acid, high API gravity, etc.) refining system  100  is illustrated in  FIG. 1 . This conventional system may be considered as a candidate for replacement of a portion of the refinery&#39;s conventional crude with a similar volume of lower quality Opportunity Crude. Many other conventional crude configurations are possible, however, which may benefit from the present invention. Thus,  FIG. 1  is just one example of a conventional crude configuration that may benefit from the present invention. In order to realize the benefits of a low cost Opportunity Crude, the capital cost of equipment modifications and additions must represent an acceptable return on investment and the yield and quality of refined products must meet market demand goals and product quality specifications. Unfortunately, prior art systems have been insufficient to do so or have required extensive modifications. 
         [0009]    In operation of a typical and conventional crude refining system, conventional crude is routed through Desalting and Preheat Units  102 , a Fired Heater Unit  103  (which may be an atmospheric crude fired heater), an Atmospheric Crude Distillation Tower  104 , a Fired Heater Unit  105  and a Vacuum Distillation Tower  106  to produce a number of product fractions. As all are of equal importance in the process, no single product or product fraction is generally considered the principal product, rendering the others “by-products;” however, to the extent any one product is considered the principal product, such as gasoline, the others may be considered “by-products” of the process of gasoline production and thus, the terms “product” and “by-product” may be used synonymously herein. The Atmospheric Crude Distillation Tower  104 , the Fired Heater Unit  105  and a Vacuum Distillation Tower  106  separate the conventional crude into fractions by boiling range, such that each fraction becomes a suitable feed stock for downstream conversion and treating process units. 
         [0010]    Products separated by the Atmospheric Crude Distillation Tower  104  include light gases, light naphtha (typically C 5 -180° F. boiling range as gasoline blend stock), and heavy naphtha (typically 180°-400° F. boiling range), which may be provided as a feed stock to the downstream Catalytic Hydrotreating and Catalytic Reforming Unit  110 . Light gases are separated from naphtha in the Gas Recovery Unit  108 . Products of the Gas Recovery Unit  108  include C 3 -C 4  Liquefied Petroleum Gas (LPG) and refinery fuel gas, which may be burned in refinery furnaces. 
         [0011]    Heavy naphtha undergoes contaminant sulfur/nitrogen removal and molecular rearrangement to increase gasoline octane in the Catalytic Hydrotreating and Catalytic Reforming Unit  110 . Reformed heavy naphtha becomes a gasoline blend stock. 
         [0012]    Another product of the Atmospheric Crude Distillation Tower  104  is kerosene. Kerosene (typically 380°-550° F. boiling range) is drawn from the Atmospheric Crude Distillation Tower  104  and routed to Kerosene Treating Unit  112 . Treated kerosene (e.g., low mercaptan sulfur, high smoke point, etc.) may be sold as commercial kerosene or, with suitable freeze point, aromatics concentration, gum, and flash point, as jet engine fuel. 
         [0013]    Another product of the Atmospheric Crude Distillation Tower  104  is diesel. Diesel (typically 500°-680° F. boiling range) is drawn from the Atmospheric Crude Distillation Tower  104  and routed to the Diesel Hydrotreating Unit  114 . Catalytic hydrotreating reduces sulfur content to meet ultra low sulfur diesel specifications for on-road transportation fuel service. 
         [0014]    Heavy atmospheric gas oil (typically 650°-750° F. boiling range) is drawn from the Atmospheric Crude Distillation Tower  104  and routed to the Fluidized Catalytic Cracking Unit  116 . 
         [0015]    High boiling (typically, 650° F. and higher) atmospheric residue from the bottom of the Atmospheric Crude Distillation Tower  104  flows through the Fired Heater Unit  105  and the Vacuum Distillation Tower  106 . 
         [0016]    Products of the Vacuum Distillation Tower  106  are vacuum gas oils (typically 625°-1,000° F. boiling range), which are provided as a feed stock to the Fluidized Catalytic Cracking Unit  116 , and vacuum residue (typically 1000° + F.), which may be used as high sulfur fuel oil or asphalt. 
         [0017]    Vacuum gas oils are routed to the Fluidized Catalytic Cracking Unit  116 , which may or may not include a catalytic hydrotreating pre-treatment step. In the fluidized catalytic cracking process, higher boiling vacuum gas oils are cracked into more valuable diesel and gasoline boiling range products. Byproduct LPG and fuel gas are recovered and separated within the Fluidized Catalytic Cracking Unit  116 . The diesel product becomes a feed stock to the Diesel Hydrotreating Unit  114 , while the gasoline product is routed to the Gasoline Hydrotreating Unit  118  for sulfur removal to meet specifications for low sulfur gasoline. 
         [0018]    The most common prior art configuration and technical basis for replacing a portion of the refinery&#39;s conventional crude with a similar volume of lower quality Opportunity Crude is illustrated in  FIG. 2 , an exemplary prior art process  200 , particularly for purposes of comparison. 
         [0019]    In  FIG. 2 , conventional crude and Opportunity Crude compose a blended feed stock referred to as “Opportunity Crude Blend” for this system  200  rather than using only conventional crude. Conventional crude and especially Opportunity Crude contain salts, sand, clay and sediments that could foul exchangers and certain material can poison downstream catalysts. Salts are frequently present in the form of Calcium, Sodium and Magnesium Chlorides. The high temperatures that occur downstream in the system  200  could allow the formation of corrosive hydrochloric acid. Therefore, the first step is to feed the Opportunity Crude Blend through a desalter where salts, suspended solids and free water are removed at low temperatures before this feed stock is preheated in a series of heat exchangers and a fired heater. Having a higher proportion of Opportunity Crude in the Opportunity Crude Blend will raise the specific gravity, lower the API gravity, and increase the viscosity and salt content of the material passing through the Desalting and Preheat Units  202 . These factors will make desalting more difficult, resulting in the need for more desalting capacity to increase residence time and facilitate oil/water separation, along with higher operating temperature and pressure, to suppress vaporization. As the operating conditions of the Desalting and Preheat Units  202  will also become inadequate for the new function, a replacement desalter, capable of higher temperatures and with a higher mechanical design pressure must be considered. 
         [0020]    A Fired Heater Unit  203  associated with the Atmospheric Crude Distillation Tower  204  may be used to heat up the Opportunity Crude Blend to a desired temperature (between 650°-700° F. depending on the type of feed stock) before it enters an Atmospheric Crude Distillation Tower  204 . Opportunity Crude with high Total Acid Number (“TAN”) (particularly high naphthenic acid content) are corrosive, particularly in the temperature range between 450°-700° F., wherein the naphthenic acids are concentrated. The preheat exchangers piping and surface areas as well as the furnace tube metallurgy operating in this temperature range therefore, must be upgraded in the Atmospheric Crude Distillation Tower  204 . 
         [0021]    The Opportunity Crude Blend is flashed off in the Atmospheric Crude Distillation Tower  204 , which uses pumparound cooling loops to create an internal liquid reflux. Product draws are on the top, sides, and bottom. The Atmospheric Crude Distillation Tower  204  operates on a descending temperature profile from bottom up as reflux from the top of the Atmospheric Crude Distillation Tower  204  provides the cooling medium while the Fired Heater Unit  203  in the bottom of the Atmospheric Crude Distillation Tower  204  provides heat to boil up product distillates. From the top of the Atmospheric Crude Distillation Tower  204 , at any point where the temperature may exceed 450° F., column trays and their internals must be replaced with higher metallurgy material. Since the bottom portion of the Atmospheric Crude Distillation Tower  204  would be operating at higher temperatures (between 650°-700° F. depending on the type of feed stock) and exposed high TAN corrosive attacks, the lower shell of the Atmospheric Crude Distillation Tower  204  may be insufficient absent some modification, to provide alloy lining or a weld overlay. 
         [0022]    The reduced crude exiting the bottom of the Atmospheric Crude Distillation Tower  204  is heated in a Fired Heater Unit  205  before being routed to the and the Vacuum Distillation Tower  206  to recover any gas oil from the reduced crude. Product draws are on the top, sides, and bottom. The Vacuum Distillation Tower  206  operates on a descending temperature profile from bottom up as reflux from the top of the Vacuum Distillation Tower  206  provides the cooling medium while a Fired Heater Unit  205  in the bottom of the Vacuum Distillation Tower  206  provides heat to boil up product vacuum gas oils. 
         [0023]    Light products from the top of the Atmospheric Crude Distillation Tower  204  are sent to a Gas Recovery Unit  208  to separate fuel gas from LPG. 
         [0024]    Full range naphtha recovered from the Atmospheric Crude Distillation Tower  204  is separated into light and heavy fractions. Light naphtha is sent for gasoline blending while heavy naphtha is processed through a Catalytic Hydrotreating and Catalytic Reforming Unit  210  to become a high octane gasoline component. 
         [0025]    A kerosene product from the Atmospheric Crude Distillation Tower  204  is sent to a Kerosene Treating Unit  212  to remove sulfur and mercaptans. To produce jet fuel, a certain level of aromatic saturation needs to take place in order to make the smoke point specifications of jet fuel material. 
         [0026]    A diesel product from the Atmospheric Crude Distillation Tower  204  and light gas oil from the Delayed Coker Unit  220  are combined and hydrotreated in a Diesel Hydrotreating Unit  214  to remove sulfur. In this process, the operating conditions and catalyst space velocity are selected in order to ensure both sulfur removal and a high cetane index number to meet the required specifications for Ultra Low Sulfur Diesel. These units may need to be modified from a conventional design using techniques well known in the art to manage the higher feed rates as conventional diesel hydrotreating unit reactors are not of sufficient size to address the higher feed rates and higher operating temperatures. 
         [0027]    Atmospheric gas oil from the Atmospheric Crude Distillation Tower  204 , vacuum gas oil from the Vacuum Distillation Tower  206  and heavy gas oil from the Delayed Coker Unit  220  pass through a Fluidized Catalytic Cracking Unit  216  to be further converted to lighter products. These products range from LPG, naphtha, LCO and slurry oil. With the use of Opportunity Crude, feeds to the Fluidized Catalytic Cracking Unit  216  are expected to contain higher level of contaminant requiring a higher catalyst replacement rate. 
         [0028]    A gasoline product from the Fluidized Catalytic Cracking Unit  216  is routed to the Gasoline Hydrotreating Unit  218  to remove sulfur down to 30 or 10 ppm with minimum octane loss. 
         [0029]    A vacuum resid from the bottom of the Vacuum Distillation Tower  206  is sent to the Delayed Coking Unit  220 , which also includes gas recovery and naphtha hydrotreating units, in order to convert this resid material to lighter products, such as light gas oil and heavy gas oil while minimizing LPG production. 
         [0030]    Various other modifications have explored replacing a portion of the refinery&#39;s conventional crude with a similar volume of lower quality Opportunity Crude such as, for example, that disclosed in U.S. Patent Application Publication No. 2010/0206773 A1, U.S. Patent Application Publication No. 2010/0206772 A1, and U.S. Patent Application Publication No. US 2004/0164001 A1. These, however, have utilized expensive conversion methods for the opportunity crude, with associated higher capital expenditure and higher operating costs, and did not explore the use of delayed coking for conversion. 
         [0031]    The prior art therefore, is limited by processing conventional crude and opportunity crude in a combined stream or train, which exposes components to corrosive crude constituents, destroying them over time. 
       SUMMARY OF THE INVENTION 
       [0032]    The present invention therefore, meets the above needs and overcomes one or more deficiencies in the prior art by providing systems and methods for refining of corrosive crudes. Conventional crude and heavy, corrosive, contaminant-laden carbonaceous crude in partially separated streams or trains. 
         [0033]    In one embodiment, the present disclosure includes a system for processing an opportunity crude, comprising: i) at least one of a pre-flash heater and an evaporator column for separating the opportunity crude into a light material and a heavy material; and ii) a delayed coker for processing the heavy material. 
         [0034]    In another embodiment, the present disclosure includes a system for processing an opportunity crude, comprising: i) at least one of a pre-flash heater and an evaporator column for separating the opportunity crude into a light material and a heavy material; and ii) an atmospheric crude distillation tower for processing only the light material and a conventional crude. 
         [0035]    Additional aspects, advantages and embodiments of the invention will become apparent to those skilled in the art from the following description of the various embodiments and related drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    The present invention is described below with references to the accompanying drawings, in which like elements are referenced with like numerals, wherein: 
           [0037]      FIG. 1  illustrates a conventional crude oil refining system. 
           [0038]      FIG. 2  illustrates a prior art configuration for replacing a portion of the refinery&#39;s conventional crude with a similar volume of lower quality Opportunity Crude. 
           [0039]      FIG. 3  illustrates one embodiment of a system for implementing the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0040]    The subject matter of the present invention is described with specificity, however, the description itself is not intended to limit the scope of the invention. The subject matter thus, might also be embodied in other ways, to include different steps or combinations of steps similar to the ones described herein, in conjunction with other present or future technologies. Moreover, although the term “step” may be used herein to describe different elements of methods employed, the term should not be interpreted as implying any particular order among or between various steps herein disclosed unless otherwise expressly limited by the description to a particular order. 
         [0041]    The following systems and methods greatly reduce the capital and operating costs for existing petroleum refineries where the conventional crude oil feedstock will be partially replaced by a lower cost, lower quality Opportunity Crude. 
         [0042]    Referring now to  FIG. 3 , one embodiment of a system  300  for implementing the present invention, which offers significant advantages in capital cost and construction cost, is illustrated. The system  300  achieves the cost-saving goals of replacing a portion of the refinery&#39;s conventional crude with a similar volume of lower quality Opportunity Crude and partially processing them separately by means of refinery modifications (equipment modifications and additions), which translate into both lower capital cost, lower construction cost, and a shorter construction schedule. By keeping the conventional crude in the conventional crude train as illustrated in  FIG. 2 , no metallurgy upgrade is necessary for most of the assets (equipment) in the system  300 . In other words, partially separating the processing of conventional crude and Opportunity Crude in the system  300  eliminates the high-TAN acid crude component from some of the equipment in the system  300 . 
         [0043]    In the system  300 , only conventional crude  314  is fed through the Desalting and Preheat Units  312 . The volume of conventional crude  314  to be processed therefore, may be reduced and replaced by at least the same volume of Opportunity Crude  302 . The optimum amount of each can vary and will be determined by refinery economics. Conventional crude  314  contains less salts, foulants and sediments than those found in Opportunity Crude  302 . Therefore, by keeping the conventional crude  314  separate from the Opportunity Crude  302 , existing system (i.e. equipment) may be utilized with nominal changes. 
         [0044]    The conventional crude  314  enters Desalting and Preheat Units  312  where salts and suspended solids are removed at low temperature. This feed is preheated in a series of heat exchangers and a Fired Heater Unit  316 . The Fired Heater Unit  316  is used to heat up the conventional crude  314  to a desired temperature (between 650°-700° F. depending on the type of feed) before this material is fed to an Atmospheric Crude Distillation Tower  318 . 
         [0045]    Exiting the Fired Heater Unit  316 , the conventional crude  314  is flashed off in the Atmospheric Crude Distillation Tower  318 , which uses pumparound cooling loops to create internal liquid reflux. Product draws are on the top, sides, and bottom of the Atmospheric Crude Distillation Tower  318 . The Atmospheric Crude Distillation Tower  318  operates on a descending temperature profile from the bottom up as reflux from the top of the Atmospheric Crude Distillation Tower  318  provides the cooling medium while a fired heater in the bottom of the Atmospheric Crude Distillation Tower  318  provides heat to boil up product distillates. Light products  350  from the top of the Atmospheric Crude Distillation Tower  318  are sent to a Gas Recovery Unit  352  to separate fuel gas  354  from LPG  356 . 
         [0046]    Full range naphtha from the Atmospheric Crude Distillation Tower  318  is separated into a light fraction  358  and a heavy fraction  360 . The light naphtha fraction  358  is sent for use in gasoline blending  372  to produce gasoline  374  while the heavy naphtha fraction  360  is sent to a Catalytic Hydrotreating and Catalytic Reforming Unit  362  to produce a high octane gasoline for use in gasoline blending  372  to produce gasoline  374 . 
         [0047]    A kerosene product  364  from the Atmospheric Crude Distillation Tower  318  is sent to a Kerosene Treating Unit  366  to remove sulfur and mercaptans and produce jet fuel  376 . To produce jet fuel  376 , a certain level of aromatic saturation must take place in order to make the smoke point specifications of jet fuel. 
         [0048]    A diesel product  320  from the Atmospheric Crude Distillation Tower  318 , light gas oil  334  from the Delayed Coker Unit  330  and a product for diesel fuel  340  from the Fluidized Catalytic Cracking unit (FCCU)  338  are sent to a Diesel Hydrotreating Unit  336  to remove sulfur and produce a diesel component  382  for Ultra Low Sulfur Diesel. The operating conditions and catalyst space velocity are therefore, selected in order to ensure both sulfur removal and a high cetane index number to meet the required specifications for the diesel component  382 , which may be used for Ultra Low Sulfur Diesel. Due to the higher feed rates, the Atmospheric Crude Distillation Tower  318  may need to be modified from a conventional design using techniques well known in the art to manage the higher feed rates. 
         [0049]    Atmospheric gas oil  368  from the Atmospheric Crude Distillation Tower  318 , vacuum gas oil  328  from the Vacuum Distillation Tower  324  and heavy gas oil  332  from the Delayed Coker Unit  330  are sent to the FCCU  338  to be converted into lighter products. These products range from LPG  378 , naphtha  342 , to light cycle oil and slurry oil. Due to the higher feed rates, the FCCU  338  may need to be modified from a conventional design using techniques well known in the art to manage the higher feed rates. With the use of Opportunity Crude  302 , heavy gas oil  332  from the Delayed Coker Unit  330  is expected to contain a higher level of contaminants requiring higher catalyst replacement. 
         [0050]    Naphtha  342  from the FCCU  338  is sent through a Gasoline Hydrotreating Unit  344  to reduce the sulfur concentration to  10 - 30  ppm with minimum octane loss thus, producing a product for use in gasoline blending  372  to produce gasoline  374 . 
         [0051]    The reduced crude  322  from the bottom of the Atmospheric Crude Distillation Tower  318  is heated in a Fired Heater Unit  380  before being fed to the Vacuum Distillation Tower  324  to recover any gas oil from the reduced crude  322 . 
         [0052]    The Opportunity Crude  302  enters a Desalting and Preheat Units  304  where salts and suspended solids are removed from the oil at low temperatures and the oil is preheated in one or a series of heat exchangers. The product of the Desalting and Preheating Units  304  is then heated in the heater of the Heater and Evaporator Column  306 . Due to the high acidity of this product, upgraded metallurgy may be used in areas where its temperature is greater than 450° F. with higher operating conditions anticipated for high temperature/pressure desalting. The heat exchangers of the Desalting and Preheat Units  304  and the heater of the Heater and Evaporator Column  306  may be designed for high viscosity material and may require upgraded metallurgy, which may be accessed based on specific feedstock characteristics. 
         [0053]    The Heater and Evaporator Column  306  is used to separate condensate and remove any light material  308  with a boiling point below 650° F. (referred to as 650° F.− or low boiling Opportunity Crude), which is fed to Atmospheric Crude Distillation Tower  318 . A heavy material  310  with a boiling point above 650° F. (referred to as 650° F.+ or high boiling Opportunity Crude) at the bottom of the Heater and Evaporator Column  306  is sent directly to the Delayed Coker Unit  330  to save the cost of a new alloy-lined vacuum unit. Another embodiment, however, may include a vacuum unit upstream of the Delayed Coker Unit  330 . This separation point, of about 650° F. may be adjusted depending on the characteristics of the opportunity crude, including down to 600° F. or up to 750° F. However, while a higher temperature is better, as it results in the need for smaller vacuum-related components, the effects of higher temperature on the opportunity crude may be problematic, including cracking of the opportunity crude, particularly within the piping. 
         [0054]    Vacuum resid  326  from the Vacuum Distillation Tower  324  together with the heavy material  310  are sent to the Delayed Coker Unit  330  in order to convert the vacuum resid  326  to lighter products, such as light gas oil  334 , heavy gas oil  332 , LPG  384 , and fuel grade coke  370  while minimizing gasoline production. A dual function crude atmospheric fractionator incorporated into the Delayed Coker Unit  330  will also serve as a fractionator for coker products thus, eliminating the need for a vacuum distillation unit upstream of Delayed Coker Unit  330  as explained previously. Process operating costs can be further reduced when utilizing heat from coke drum vapor at or about 800° F. to preheat coker feed thereby, eliminating or greatly reducing the size of a separate fired heater for the dual function crude atmospheric fractionator. Thus, the atmospheric pressure flash unit operation and delayed coker product fractionation are incorporated into a single fractionation tower of the Delayed Coker Unit  330 . The Delayed Coker Unit  330  may include a dual function crude atmospheric fractionator. Thus, this configuration eliminates or reduces the need for a conventional delayed coker fired heater and thus reduces the capital cost of the coker unit. 
         [0055]    Delayed Coker Unit  330  may also include conventional gas recovery unit and naphtha hydrotreating components to produce a treated product  348  for gasoline blending, which is sent for use in gasoline blending  372  to produce gasoline  374 . Distillate products (naphtha, diesel, gas oil) from the Delayed Coker  330  can be integrated with refinery hydroprocessing (hydrotreating, hydrocracking, hydro-isomerization). The Delayed Coker Unit  330  offers a shift toward higher value products such as middle distillates over gasoline. Due to special design features for Delayed Coker Unit  330 , the system  300  may also focus on maximizing middle distillate production. 
         [0056]    The system  300  may be implemented in most, if not all, existing refineries with a crude oil production capacity in the range of 50,000-200,000 barrels per stream/day although an existing refinery implementing the system  300  may, or may not, have existing resid bottoms upgrading (i.e. coking, solvent deasphalting, thermal cracking, visbreaking). By separating the Opportunity Crude  302  from the conventional crude  314  and directing the heavy material  310  and the vacuum resid  326  from the Vacuum Distillation Tower  324  to the Delayed Coker Unit  330 , the system  300  avoids the need for significant equipment modifications and metallurgy upgrades in an existing refinery. The selection of Opportunity Crude type and feed rate are key evaluation factors for implementation of the system  300  to both optimize the capital cost of new equipment and minimize impacts to the existing refinery equipment (hydroprocessing, catalytic cracking, etc.). The system  300  thus, offers a low capital expenditure solution while minimizing field construction labor and downtime for the modification of existing refinery equipment. The system  300  can be implemented and applied to a modification of existing refinery assets (or equipment) with or without expansion of the refinery crude processing capacity. 
         [0057]    The advantages of the system  300  thus, include:
       combining the atmospheric pressure flash unit operation and delayed coker product fractionation functions in a single fractionation tower.   separating low quality corrosive Opportunity Crude from existing front-end processing to avoid equipment/piping modifications and metallurgy upgrades;   minimizing shutdown time and construction inefficiencies related to work in existing process units, whereby new process units can be constructed separately (green field) and tied into the existing refinery;   maximizing a middle distillates-to-gasoline ratio from bottoms upgrading to help increase refinery margins and take advantage of higher diesel and/or jet fuel demand and pricing;   integrating Opportunity Crude pre-flash and coker product fractionation to save equipment cost;   eliminating vacuum distillation required for Opportunity Crude;   using existing fuels refinery processes to manufacture finished products; and   integrating the delayed coker and the separated Opportunity Crude to reduce operating costs, which i) provides significant fraction of bitumen pre-flash heat requirement (minimize pre-flash heat duty) for a superheated coke drum vapor (800° F.); and ii) refrigerates lean oil absorption to reduce coker gas recovery costs.       
 
         [0066]    In the foregoing specification, the invention has been described with reference to specific embodiments thereof, and has been demonstrated as effective in providing systems and methods for lowering the processing cost of Opportunity Crude. However, it will be evident to those skilled in the art that various modifications and changes can be made thereto without departing from the broader spirit or scope of the invention. Accordingly, the specification is to be regarded in an illustrative rather than a restrictive sense. For example, it is anticipated that by routing certain streams differently or by adjusting operating parameters, different optimizations and efficiencies may be obtained, which would nevertheless not cause the system to fall outside of the scope of the present invention. It is therefore, contemplated that various alternative embodiments and modifications may be made to the disclosed embodiments without departing from the spirit and scope of the invention defined by the appended claims and equivalents thereof.