Abstract:
A fuel or other process fluid is cleansed by a) combining the fluid with water and an oxidizer; b) mixing the combination in a mixer having a volume V; c) separating the mixed combination into hydrophobic and hydrophilic phases; d) filtering the hydrophobic phase through a filter; e) removing water from the filtered hydrophobic phase to produce the cleaned fluid; and accomplishing steps a-d in a continuous manner that produces an output of the cleaned fuel at an average rate of at least 10V/hour. A centrifuge can optionally reduce water content of the cleaned fluid to no more than 5 ppm, more preferably no more than 1 ppm, and most preferably no more than 0.5 ppm.

Description:
[0001]    This application claims priority to us provisional application Ser. No. 60/629849 filed Nov. 19, 2004. 
     
     FIELD OF THE INVENTION 
       [0002]    The field of the invention is processing of combustible fuels. 
       BACKGROUND  
       [0003]    Many fuels, especially reclaimed or renewable fuels such as biodiesel and fermentation derived ethanol, are heavily contaminated. Upon combustion, the contaminants contribute to air pollution, and eventually water and soil pollution. In some instances the contribution is strictly chemical, and in other instances the contribution can be some combination of chemical and physical interactions. For example, the current inventor has theorized that contaminant particles create hot spots that accelerate production of unburned and/or partially burned hydrocarbons, NOx, and particulates. 
         [0004]    It is known to remove particulates from dirty fuels using a paper, resin, or other physical filter. Filters with micron sized holes, for example, can and have been used to reduce contaminants in fuels. But such filters are notoriously slow, and therefore to a large extent impractical. 
         [0005]    It is also known to remove dissolved hydrophilic contaminants by washing a dirty fluid with water. As used herein, a dirty fluid is merely a fluid that is cleaned to produce a cleaned fluid. A biodiesel recipe employing a water wash, for example, can be found at http://localaction.biz/. In some instances contaminants can be rendered hydrophobic through chemical reactions. Sulfur contaminants, for example, can be removed by hydrogenating sulfur compounds to H 2 S, and then removing the H 2 S with amine solvents. 
         [0006]    U.S. Pat. No. 4,314,902 to Bouk et al. (February 1982), (the “&#39;902 patent”), discloses a sophisticated solution to cleaning commercially available jet fuels that had been contaminated with microorganisms. This and all other cited materials are incorporated herein by reference in their entirety. Where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. 
         [0007]    The &#39;902 patent teaches batch processing of the fuel by washing the contaminated fuel with an oxidizing agent (H 2 O 2 , cupric or ferric chloride), filtering the resultant by dumping in absorbent clay, and then decanting the cleaned fuel off the top. Unfortunately, that process is not commercially viable. The process is too slow, is not amenable to continuous process, and is wasteful in that a considerable amount of fuel remains with the clay and water sludge at the bottom of the processing vessel. Still further, there is no teaching or suggestion that the process can be applied to “raw” fuels, including for example, unfiltered biodiesel or fermentation derived ethanol, which can be heavily contaminated. 
         [0008]    Thus, there is still a need for apparatus, systems, methods, and compositions for cleaning dirty fuels, and for marketing the cleaned fuels. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides apparatus, systems, methods, and compositions for marketing a fuel, comprising: providing a dirty fuel; using a process to clean the dirty fuel to produce a cleaned fuel; receiving written information from a competitor that the process is thought to be sufficient to reduce microbial contamination in biodiesel such that the cleaned biodiesel has no more than 100 CFUs/ml; and qualifying the cleaned fuel under an exhaust emissions standard. A CFU is a colony forming unit, as defined by the U.S. Department of Agriculture. 
         [0010]    All types of fuels are contemplated, including especially fuels that contain one or more of diesel, gasoline, and ethanol. Of particular interest are fuels that include a blend of biodiesels, a biodiesel and a petroleum diesel, a biodiesel and a heating oil, and a gasoline with ethanol. Preferred fuels contain no more than 1000 CFUs/ml of microbial contamination, more preferably no more than 100 CFUs/ml of microbial contamination, and most preferably no more than 10 CFUs/ml of microbial contamination. 
         [0011]    All recognized exhaust emissions standards are contemplated, including state, federal, and other standards, including for example standards announced or otherwise promulgated by SWRI (Southwest Research Institute) in San Antonio, Tex. 
         [0012]    All practical aqueous solutions are contemplated to be used in washing the dirty fuel, including water in combination with hydrogen peroxide, ozone, and chromic acid, or any other suitable chemical oxidizer. Alternatively, the process can comprise partially oxidizing the dirty fuel using electrical energy, as for example by electrolyzing the fuel with immersed electrodes. Catalysts are also contemplated, including especially catalysts that increase or decrease the rate at which the fuel is oxidized, or that preferentially oxidize a contaminant in the fuel relative to the fuel itself. Preferred catalysts include copper, iron, magnesium, manganese, nickel, zinc, chromium or other metal ions. 
         [0013]    Process controls are also contemplated. For example, it is contemplated that systems and methods can be implemented that sense an undesirable amount of a triol and a glyceride or other byproduct in a downstream portion of the cleaned fuel. Especially preferred process controls are at least partially automated, and thereby automatically modify a parameter of the process to reduce the byproduct in an upstream portion of the cleaned fuel. For example, if excess triol is detected, the system can automatically or otherwise increase hydrogen peroxide or mixing time. 
         [0014]    Preferred methods of cleaning a fuel or other process fluid comprise: a) combining the process fluid with water and an oxidizer; b) mixing the combination in a mixer having a volume V; c) separating the mixed combination into hydrophobic and hydrophilic phases; d) filtering the hydrophobic phase through a filter; e) removing water from the filtered hydrophobic phase to produce the cleaned process fluid; and accomplishing steps a-d in a manner that produces an output of the cleaned fuel at an average rate of at least 10V/hour. Such processes can advantageously be accomplished in a substantially continuous manner, for example, with one or more of steps a-d being accomplished in a substantially continuous manner. In especially preferred methods, production lines can be arranged and operated that produce cleaned fuel at an average rate of at least 25V/hour, at least 35V/hour, and even at least 50V/hour. 
         [0015]    The step of filtering preferably comprises passing the hydrophobic phase through a stationary consumable filter material. Preferred filter materials include one or more of paper, resin, activated carbon, and nano-graphene such as HRCM™ (available from SupraCarbonic, Inc, Irvine Calif.). Additional separation, especially to remove water, can be accomplished by centrifuging. Preferred centrifuges preferably reduce water content of the cleaned fuel to no more than 5 ppm, more preferably no more than 1 ppm, and most preferably no more than 0.5 ppm. 
         [0016]    The apparatus, systems, methods, and compositions described herein can also be applied to cleaning oily materials that are not intended to be used as fuels. Examples include transformer oils and lubricants. 
         [0017]    Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components. 
     
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0018]      FIG. 1  is a schematic of a fuel or other material processing system according to aspects of the inventive subject matter. 
       
    
    
     DETAILED DESCRIPTION  
       [0019]    In  FIG. 1 , a purifying system  10  generally includes feed lines for input composition  12 , oxidizer  14 , first catalyst  16 , second catalyst  18 , a mixer  20 , a separator  30 , a filter  40 , a centrifuge  50 , computer controller  60 , and an exit line  70 . Pumps  19  provide motive force for movement of the corresponding compositions. In general, the vessels and various other conduction lines described herein are preferably made of stainless steel, glass, or other material that is non-reactive to the various chemicals. 
         [0020]    Input composition  12  would usually be a liquid fuel, i.e. liquid that can reasonably be combusted to produce motive and/or heat energy. For example, fuel  12  is contemplated to include all manner of petroleum based compositions (e.g., gasoline, diesel, heating oil, and jet fuel), agriculturally based compositions (e.g., biodiesel, ethanol, olive, soybean, cotton, rapeseed, safflower, corn and other and vegetable oils), and non-petroleum, non-agriculturally based compositions (e.g. abiogenic or deep-earth gasses). On the other hand, it is expressly contemplated that input composition  12  is broad enough to include crude oil, transformer oils, greases and other lubricants, oil contaminated with fresh, salt or brackish water, byproducts of oil production from tar sands, and “reclaimed fuels”, which is defined herein as contaminated or degraded fuel that has been returned to specification (e.g. reclaimed fuel from oil sludge at the bottom of a oil tanker tanks, old jet fuel, gasoline, diesel, etc). It is also contemplated that fuel can be “renewable”, which is defined herein as agriculturally derived fuel. 
         [0021]    Oxidizer  14  can be any suitable oxidizing composition, including for example, hydrogen peroxide, ozone, and chromic acid. All suitable concentrations are contemplated, with concentrations and rates corresponding with experimentation. H 2 O 2  is preferably employed at 10%, but at least less than 50% for safety reasons. Ozone, of course, would likely be bubbled through the mixing chamber. One advantage to H 2 O 2  and ozone is that they could be generated on-site, as needed. 
         [0022]    Additional or alternatively, oxidation can be provided electrically, through electrodes  22 A,B, which are connected to a power source (not shown) through wires (not shown). Electrically produced oxidation is thought to be advantageous because it eliminates costs of transporting chemically active materials (especially strong oxidizers) to the operation site. 
         [0023]    Catalysts  16 ,  18  are intended to increase or decrease the rate at which the input composition  12  is oxidized, or that preferentially oxidizes a contaminant in the input composition relative to the input composition itself. Preferred catalysts include copper, iron, magnesium, manganese, nickel, zinc, chromium or other metal ions. The cation is considered to be the catalyst, so that the anion is usually of minimal importance other than to provide a stable ionically bound substance. Exemplary catalysts include CuCl 2  and Fe 2 Cl 3 .  FIG. 1  shows two catalysts being used, catalysts  16 , 18 , however, those skilled in the art will appreciate that one or other numbers of catalysts can be utilized, in whatever concentrations are effective, available, and otherwise desirable. 
         [0024]    Mixer  20  can utilize any suitable mixing technology. One of the most important parameters is whether the mixer imparts sufficient energy. Another important, but not critical parameter is that the mixer is suitable for continuous input and output flow, (as opposed to batch operation). Experimental versions have demonstrated good efficacy with sonic mixers, and critical orifice mixers. As to capacity, preferred mixers have a nominal capacity volume V, of at least 100 liters, more preferably. Full production plants are contemplated that handle 30,000,000 gallons a year (approx 113,562,353 liters/yr). For example, a 108 gallon (409 liters) mixer (V=108 gallons) at throughput of 35V˜3787 gallons/hour (14335 liters/hr) would produce about 30,000,000 gallons per year (assuming 24 hr/day operation, for 330 days a year). Such plants would, however, very likely utilize multiple lines and/or multiple mixers. Thus, the same result could obtain using two 54 gallon (204 liters) mixers. 
         [0025]    Other nominal mixer volumes and throughput values are also contemplated. For example, mixers are contemplated having nominal capacity volumes of approximately 25 liter, 50 liter, 75 liter, 100 liter, 150 liter, and so forth. In addition, depending on the pump capacities and mixer energy density, throughputs are contemplated up to 5V, 10V, 15V, 20V, 25V, 35V, 50V, or even 100V or more. 
         [0026]    Residence time in the mixer  20  is whatever time is needed to achieved desired mixing. In experimental devices with a small critical orifice mixer (V=1.5 liters), a suitable mixing time was about 2 minutes. Other suitable residence times in mixers are contemplated to be between about 1 minute and about 5 minutes. These and all other ranges set forth herein are inclusive of the endpoints, unless the context indicates otherwise. 
         [0027]    Downstream of the mixer  20  is the separator  30 . Separator  30  is preferably a continuous tube having a lumen with nominal volume of between 1 and 20 times that of the mixer  20 . In relatively smaller mixers, such as 1 liter experimental mixers, the capacity of the separator  30  is advantageously greater, perhaps in the range of 12-18 times that of the mixer  20 . Residence time in the separator  30  is whatever time is needed for the oxidizer(s) to substantially exhaust their oxidative capacity. This can be estimated by observing when the mixture seems to have stopped bubbling. In experimental devices a suitable residence time in the separator  30  is contemplated to be between about 2 minutes and about 30 minutes. Indeed, the separator  30  could be eliminated altogether (not shown), with the hydrophilic / hydrophobic compartment separations accomplished in the centrifuge, or elsewhere. In yet another alternative embodiment (not shown) a single mixer could feed multiple separators. 
         [0028]    Filter  40  is preferably an in-line filter, with a capacity to drain off the bottoms fluid, which is the hydrophilic compartment separated out in the separator  30 . Filter  40  preferably includes a disposable or regenerable physical filter, including for example, a paper or resin. Alternatively or additionally the filter  40  can include activated carbon, HRCM™ or other absorbent material. Residence time in the filter  40  is advantageously quite small, on the order of a minute or less. System  10  preferably includes dual filters  40  with an appropriate valve such that one filter can be shut down for repair, replacement, or regeneration without interrupting operation of the system. 
         [0029]    Centrifuge  50  is intended to remove small quantities of remaining water. Any continuously operating centrifuge of sufficient capacity is acceptable. The speed and configuration should be such that water can be removed down to at most 5 ppm, more preferably at most 1 ppm, and most preferably at most 0.5 ppm. Removal of remaining water is important in many applications because the remaining water contains soluble contaminants. 
         [0030]    Computer controller  60  has sensor feeds  62  from various sensors  62 A- 62 E in the system  10 . For example, one sensor  62 A could measure whether oxidation is substantially completed, another sensor  62 B could measure whether sufficient separation has occurred, another sensor  62 D could detect whether the filter needs changing, and yet another sensor  62 E could detect remaining impurities. Executing appropriate software (not shown), and using control wires (not shown), the controller  60  can advantageously operate pumps  19 . Pumps  19  are any suitable pumps, preferably operating under the control (directly or indirectly) of the controller  60 . 
         [0031]    Thus, specific embodiments and applications of fuel purifying systems have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.