Patent application title: PROCESS AND SYSTEM FOR PRODUCING BIODIESEL FUEL
Michael Joseph Perrier (New Westminster, CA)
Next Energy Systems Inc.
IPC8 Class: AC10L108FI
Class name: Liquid fuels (excluding fuels that are exclusively mixtures of liquid hydrocarbons) plant or animal extract mixtures or extracts of indeterminate structure containing containig triglycerides (e.g., castor oil, corn oil, olive oil, lard, etc.)
Publication date: 2009-03-19
Patent application number: 20090071063
Disclosed and claimed herein is a system and method for producing
biodiesel fuel from low quality feedstock sources of free fatty acids.
The system includes a reaction chamber having a jacket for circulating
heating fluid around the chamber; a feedstock pre-treatment assembly; a
methoxide reaction tank; a settling tank; a crude biodiesel wash
assembly; and, a methanol recovery assembly, also referred to as a
methanol recoverer herein.
The method includes the steps of pre-treating the feedstock by heating
and, optionally, filtering it; reacting the feedstock in the reaction
chamber with a source of esters thereby carrying out transesterfication
of the free fatty acids, thereby producing an intermediate reaction
product, cooling the intermediate reaction product to allow glycerine to
settle out, separating the glycerine from the crude biodiesel, and
washing the crude biodiesel to remove impurities, thereby producing
1. A method of producing biodiesel fuel from a feedstock source of free
fatty acids, said method comprising the steps of:(a) pre-treating the
feedstock, wherein said the pre-treating comprises heating the
feedstock;(b) in a reaction chamber, carrying out a transesterification
reaction between a source of esters and the free fatty acids of the
pre-treated feedstock of Step (a) to yield intermediate reaction product,
wherein carrying out the transesterification reaction comprises
circulating heated heating fluid through a jacket surrounding the outside
surface of the reaction chamber, whereby the reaction temperature is
maintained at a predetermined temperature;(c) allowing the intermediate
reaction product of Step (b) to cool sufficiently to cause glycerine to
settle out, thereby separating the glycerine from crude biodiesel;(d)
removing the separated glycerine from the crude biodiesel; and,(e)
washing the crude biodiesel, whereby the biodiesel fuel is produced.
2. The method of claim 1 wherein methoxide is the source of esters.
3. The method of claim 2 further comprising:(f) recovering methanol from waste fluids produced by at least one of Step (d) and Step (e).
4. The method of claim 3 wherein Step (f) comprises the steps of:(f1) heating the inner surface of a drum to a temperature above the boiling point of methanol;(f2) spraying the waste fluid onto the inner surface of a drum heated at Step (f1), thereby producing methanol vapors;(f3) passing the methanol vapors produced at Step (f2) through a condenser, wherein the temperature of the condenser is maintained at a temperature below the boiling point of methanol, thereby producing a liquid methanol condensate; and,(f4) collecting the methanol condensate of Step (f3).
5. The method of claim 4 wherein Step (f1) is performed with heat produced by an oil burner that burns biodiesel fuel produced at Step (e).
6. The method of claim 4 further comprising reducing the air pressure within the drum, thereby lowering the boiling point of methanol.
7. The method of claim 1 wherein the feedstock is heated to approximately 43.degree. C. at Step (a).
8. The method of claim 1 wherein Step (b) further comprises mixing the source of esters and the free fatty acids in the reaction chamber by rotating at a rotation speed a paddle mounted in the reaction chamber, wherein the rotation speed is from about 60 RPM to about 80 RPM.
9. The method of claim 1 wherein at least one of i) heating the feedstock at Step (a) and ii) heating the heating fluid of Step (b) comprises burning biodiesel fuel from Step (e).
10. The method of claim 1 wherein Step (a) further comprises at least one of i) filtering the feedstock, and ii) de-watering the feedstock.
11. The method of claim 1 wherein the predetermined temperature of Step (b) is below the boiling point of methanol.
12. The method of claim 1 wherein Step (e) comprises the steps of:(e1) precipitating impurities from the crude biodiesel, and(e2) separating the biodiesel fuel from the impurities.
13. The method of claim 12 wherein Step (e) further comprises forcing compressed gas through the crude biodiesel, whereby the crude biodiesel is mixed.
14. A system for producing biodiesel fuel from at least one feedstock source of free fatty acids, said system comprising:(a) a reactor comprising:(a1) a reaction chamber;(a2) reactor heating means for heating reactants in said reaction chamber; and,(a3) mixing means for mixing reactants in said reaction chamber;(b) a feedstock pre-treatment assembly comprising:(b1) a pre-treatment tank; and,(b2) a feedstock heating means, wherein said pre-treatpre-treatment tank is in communication with said reaction chamber to allow said reaction chamber to receive pre-treated feedstock from said pre-treatment tank;(c) a methoxide reaction tank in communication with said reaction chamber such that said reaction chamber receives methoxide produced in said methoxide reaction tank;(d) a settling tank in communication with said reaction chamber, wherein said settling tank receives intermediate reaction product from said reaction chamber;(e) a wash assembly comprising a wash tank in communication with said settling tank, wherein said wash tank receives crude biodiesel from said settling tank; and,(f) a methanol recovery assembly.
15. The system of claim 14 wherein said reactor heating means comprises a jacket means for circulating heated heater fluid around said reactor chamber; and, a heater for heating the heating fluid.
16. The system of claim 15 wherein said heater comprises an oil burner adapted to burn biodiesel fuel produced by the system.
17. The system of claim 14 wherein said feedstock heating means comprises:(b3) a radiator through which heated heating fluid flows, said radiator being in thermal communication with the feedstock;(b4) a heater for heating the heating fluid; and,(b5) a pump for pumping the heated heating fluid through said radiator.
18. The system of claim 17 wherein said heater is an oil burner adapted to burn biodiesel fuel produced by the system.
19. The system of claim 14 wherein said mixing means of said reactor comprises at least one internal paddle mounted within said reaction chamber; and, rotation means for rotating said paddle.
20. The system of claim 14 wherein said mixing means of said reactor comprises at least one baffle.
21. The system of claim 14 wherein said methanol recovery assembly comprises:(g1) a drum having an interior volume bounded by an interior wall surface;(g2) a drum heating means for heating said interior wall surface to a temperature equal to or greater than the bolting point of methanol;(g3) a spray head;(g4) a pump for forcing methanol containing fluids through said spray head;(g5) a condenser; and,(g6) a vapor pump in communication with i) said drum interior volume, and ii) said condenser;wherein said spray head is adapted to deposit the methanol-containing fluid against said drum interior wall surface, thereby producing methanol vapors in the interior volume of said drum when said interior wall surface is heated to a temperature equal to or above the boiling point of methanol, and wherein said vapor pump is adapted to pump the methanol vapors from the interior volume of said drum to said condenser.
22. The system of claim 14 wherein at least one of said reactor heating means and said feedstock heating means comprises an oil burner adapted to burn biodiesel fuel produced by said system.
23. The system of claim 14 further comprising a vehicle for carrying said reactor, said pre-treatment assembly, said methoxide reaction tank, said settling tank, said wash assembly, and said methanol recovery assembly.
24. The system of claim 23 further comprising a diesel-powered electric generator mounted in or on said vehicle, wherein said generator is adapted to burn biodiesel fuel produced by the system.
25. The system of claim 14 wherein said wash assembly further comprises means for injecting compressed air into the crude biodiesel being washed, thereby mixing the crude biodiesel.
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus and process for converting free fatty acids in acid oil or acid fat to fatty acid methyl esters, commonly known as "biodiesel."
Biodiesel--generally, processed fuel, derived from biological sources of free fatty acids, and that can be used as a substitute, supplement, and/or alternative fuel in un-modified diesel engines or other devices that burn diesel oil.
Feedstock--refers to vegetable oils, animal fats, and other sources of free fatty acids (FFAs) amenable to conversion to biodiesel by transesterification.
Biodiesel fuel--the biodiesel end-product produced by the process and system of the present invention.
Intermediate reaction product--an intermediate-stage product formed of the transesterification reaction prior to removal of glycerine.
Crude biodiesel--an intermediate-stage product produced following by the removal of glycerine from the intermediate reaction product.
BACKGROUND SUMMARY WITH REFERENCE TO EXISTING ART
Biodiesel is a non-toxic, biodegradable, and renewable diesel-equivalent fuel that is produced from organic feedstocks such as vegetable oils or animal fats through transesterification of free fatty acids (FFAs) into fatty acid methyl esters (FAMEs). This process utilizes a catalyst, an alcohol, and a source of fatty acids such as vegetable oil. The preferred alcohol is methanol, although higher weight alcohols can be used. The methanol is reacted with sodium hydroxide to produce methoxide, which drives the transesterification reaction. The resultant purified liquid is biodiesel. The by-products include methanol and glycerine. Glycerine settles out of the reacted liquid and can easily be isolated.
Conventional methods of transesterification of vegetable oils proceed by mixing methanol and sodium hydroxide with vegetable oil in a tank and heating the mixture to about 66° C. to 71° C. (151° F.-160° F.) This temperature is maintained for hours while mixing paddles stir the mixture, generally at a rotation rate in excess of 100 RPM. During this process the methanol, which has a boiling point of 64.7° C., is vaporized and glycerine precipitates out. Further impurities are removed in a wash tank and a final filtration is performed. The biodiesel fuel that is left has properties very similar to diesel oil but burns with about 70% fewer pollutants.
In order to speed up the trans-esterification reaction, a catalyst is often employed. Typically the catalyst is a base catalyst such as NaOH. However, lower quality (i.e., cheaper) feedstocks have high FFA content and the FFAs tend to form soap with base catalysts, thus reducing yield and presenting significant operational problems.
One approach to solving this problem has been using a large excess of methanol and an acid catalyst. U.S. Pat. No. 6,965,044 to Hammond discloses the use of acid catalysts to avoid these problems. However, the method of Hammond et al. uses 2-4 hour pre-treatment and a 24-hour reaction time. Similarly long process times are found with conventional, base catalysis methods, which take about 3 hours to reach full temperature and several more hours to react. Because of the high cost of the methanol it is necessary to recycle the methanol when using excess amounts, but recovering methanol has been problematic and expensive.
A system with shorter reaction times, using a base catalyst, carried out at lower temperatures, that avoids saponification, and that can produce refined biodiesel fuel from low grade feedstocks is needed. Hammond states that "[t]he base catalyst-catalyzed transesterification reaction, commonly used for generating FAMEs from refined vegetable oils, cannot be used to produce biodiesel from the cheaper starting materials with high FFA content . . . since the FFAs in the materials form soaps with the base catalyst." As a result of the present process and system, that statement is no longer accurate.
SUMMARY OF THE INVENTION
Disclosed and claimed herein is a system and method for producing biodiesel fuel from any feedstock sources of free fatty acids, including low quality sources. The system includes a reaction chamber having a jacket for circulating heating fluid around the chamber; a feedstock pre-treatment assembly; a methoxide reaction tank; a settling tank; a crude biodiesel wash assembly; and, a methanol recovery assembly, also referred to as a methanol recoverer herein.
The method includes the steps of pre-treating the feedstock by heating and, optionally, filtering it; reacting the feedstock in the reaction chamber with a source of esters thereby carrying out transesterfication of the free fatty acids; producing an intermediate reaction product; cooling the intermediate reaction product to allow glycerine to settle out; separating the glycerine from the crude biodiesel; and, washing the crude biodiesel to remove impurities, thereby producing biodiesel fuel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1. is a flow chart of the method of the invention.
FIG. 2. is a schematic diagram of the system of the invention.
FIG. 3. is a schematic diagram of the preferred physical arrangement of the major elements of the system.
FIG. 4. is a schematic diagram of the methanol recoverer of the system.
FIG. 5. is a side-elevation schematic drawing of the system described herein mounted in a vehicle, namely a trailer.
FIG. 6. is a cross-section of the reactor when looking down thereupon.
FIG. 1 is a flow diagram summarizing the basic steps of the method of the invention. Raw fryer oil or other feedstock is acquired as a starting product. A major advantage of the present process and system is that a low quality feedstock can be used as a source of free fatty acids with good results. The feedstock is pre-treated by heating 101 to approximately 43° C. (109° F.), optionally de-watering, and optionally filtering 201. Prior to filtering, the heated feedstock is allowed to cool and then filtered by passing it through a bag filter. The filtered feedstock is transferred to a reactor by means of dual-diaphragm, air driven pump.
Various alcohols, including methanol, ethanol, butanol, and isopropanol, can be used as a source of esters. Methanol is preferred. In a methoxide reaction tank, methanol is reacted with a base to produce methoxide. The preferred base is sodium hydroxide, thereby producing sodium methoxide 301 (also known as sodium methylate). The reaction between sodium hydroxide and methanol is run at ambient temperature for about 15 minutes to about 30 minutes. The reaction mixture, which includes methoxide, and unreacted methanol and sodium hydroxide, is transferred to the reactor.
The transesterification reaction between the methoxide and the pre-treated feedstock 401 takes place in a reactor chamber of the reactor to produce an intermediate reaction product, which is an unrefined mixture of esters, unreacted methanol, glycerine, water, and other by-products. The transesterification reaction takes place at about 38° C.-66° C. (100°-151° F.), with the preferred reaction temperature being 43° C. (109° F.)
This temperature is notable and preferred because it is lower than reaction temperatures currently used in the art and, significantly, is below the boiling point of methanol. This reduced reaction temperature minimizes saponification and premature vaporization and subsequent loss of methanol prior to the methanol recovery process described below. The reaction temperature is maintained by circulating a heated heating fluid around the outside surface of the reaction chamber, as described in more detail below.
The preferred ratio of sodium methoxide to feedstock, by volume, is approximately 200 l. of sodium methoxide to 1000 l. of feedstock.
The transesterification reaction is promoted by slowly mixing the reactants in the reaction chamber with a rotating paddle run at a rotation rate from about 60 RPM to about 80 RPM. In spite of the low reaction temperature and slow paddle rotation rate, the reaction time is only approximately 60-75 minutes for a reaction batch volume of 4000 l. The paddle rotation rates and reaction temperatures below those used in the existing art are unexpected benefits of the efficient and uniform thermal transfer of the jacketed reaction chamber and the enhanced cavitation caused by the baffles. These benefits are very significant because they avoid the problems of aeration, saponification, and premature methanol vaporization whilst decreasing overall production time.
Following the transesterification reaction, the intermediate reaction product, which contains, inter alia, crude biodiesel and glycerine, is transferred to a settling tank where the reaction product is cooled sufficiently to promote the settling out of the glycerine 501. The glycerine, once separated from the crude biodiesel, is recovered 601 for disposal or market 1001. Waste fluid, which contains unreacted methanol, is separated from the crude biodiesel and subjected to methanol recovery 1201 in a manner described in detail below.
The crude biodiesel is decanted 701 into a wash tank for washing 801 by means of the addition of magnesium silicate [Mg3Si4O.sub.10(OH)2] at approximately 0.05% to approximately 1.5% wt./volto promote dehydration of the crude biodiesel and the precipitation of impurities such as methanol and sodium methoxide. The washing step is promoted by optionally injecting a compressed gas, preferably air, through the crude biodiesel to promote mixing. The product of the wash step is the biodiesel fuel, which is separated from the precipitated impurities. The waste fluid from the wash step is subjected to methanol recovery 1201 in a manner disclosed in detail below.
The biodiesel fuel 901 is stored until it is sent to market 1001. A portion of the biodiesel fuel is used to fire the boiler used to heat the heating fluid, normally water, 1101 that is used to: (1) pre-heat the raw material 1301; (2) heat the reaction 1401, and (3) heat the methanol recovery apparatus 1501.
An important aspect of the process is the recovery and reuse of unreacted methanol 1201 from one or both of the waste fluid taken from the glycerin settling step 501 and the washing step 801 Briefly, the methanol recovery process is accomplished by heating the waste methanol in a sealed flash drum to a temperature above the methanol boiling point. A temperature of approximately 80° C. (176° F.) is preferred. The methanol vapors are drawn off by means of a vacuum pump, which pumps the vapors into a condenser where the vapors are cooled and liquid methanol collected. The recovered methanol is recycled 1601 to produce more methoxide 301. Non-volatile components are collected and disposed of. A methanol recoverer device for carrying out this step is disclosed in detail below.
In FIG. 2 is shown a preferred system and best known mode for carrying out the method of the invention.
There is provided at least one raw materials holding tank 102 for holding the fryer oil or other feedstock source of fatty acids that is to be processed by the method.
The holding tank is in communication with a pre-treatment assembly that includes a pre-treatment tank 202, which optionally has a heating radiator 1202 positioned within the tank so as to be in contact with the feedstock, the heating radiator being used to heat the feedstock during pre-treatment thereof. Heated heating fluid, normally water, is circulated through the radiator 1202 by a pump (not shown) and is thus in thermal communication with the feedstock. The water can be heated by any type of heater, but an oil burner 1302 is preferred because it can be burn biodiesel fuel produced by the system.
Radiator 1202 comprises sinusoidal piping having metal heat dispersion fins attached thereto.
Control valves, one of which is designated 1102, are provided where necessary for controlling the flow of reactants, product, heating water, and by-products.
Tanks for holding sodium hydroxide 502 and methanol 402 communicate with a methoxide reaction tank 602 for reacting sodium hydroxide and methanol to produce sodium methoxide.
Both the methoxide reaction tank 602 and feedstock pre-treatment tank 202 communicate with reactor 302. The pre-treated feedstock is transferred to reactor chamber 1502 by means of a dual-diaphragm air driven pump. A filter for filtering the pre-treated oil 1402, preferably a bag filter, is optionally provided between the pre-treatment tank and the reactor. The pre-treatment may also include dewatering apparatus for dewatering feedstock prior to the transesterification reaction (FIG. 1, 401).
The reactor includes a jacket 302 for circulating hot water generated by boiler 1302 around the outside surface of reactor chamber 1502. Although FIG. 2 shows only one reactor, multiple reactors can easily be incorporated into the system. At present, two reactors are preferred. The reactor is described in more detail below.
The reactor chamber 1502 is in communication with glycerine settling tank 902. Upon completion of the transesterification reaction (FIG. 1, 401), the reactants are transferred to the glycerine settling tank to separate glycerine from the biodiesel product. The settled glycerine is transferred to a glycerine holding tank 1002, methanol is removed from the crude biodiesel prior to the crude biodiesel being washed, and the crude biodiesel product is transferred to wash tank 802. Unreacted materials removed from the crude biodiesel, which includes methanol, are transferred to methanol recoverer 1702.
Washing, which includes dehydration of the product, takes place in wash tank 802. The tank optionally has a "mixing wand" 1902 mounted in it, which mixing wand comprises an elongate tube with holes in the wall of the tube. One end of the mixing wand is connected to a source of compressed air. The compressed air is forced through the wand and out the holes, thereby being injected into the crude biodiesel and providing a safe and effective method of mixing the crude biodiesel during washing.
Following washing, the finished diesel product is transferred to a holding tank 702. Residue fluids from the washing process, which fluids include unreacted methanol, are transferred to a methanol recoverer 1702. Although FIG. 2 shows only a single methanol recoverer for clarity, in practice at least two methanol recoverers are preferred, one recovers methanol from the glycerine settling step waste fluid and the other recovers methanol from the wash step waste fluid.
Optionally, a means is provided to feed a portion of the finished biodiesel product back to oil burner 1302. This may be a fuel line 1602 with a demand control apparatus such as a float valve or computer controlled pump, or it may be simply removing a portion of the product from the holding tank 702 periodically and adding it to a fuel tank for the oil burner.
As noted above, methanol-containing waste fluids are fed into one or more methanol recoverers 1702, which have water jackets for circulating hot water generated by oil burner 1302. Methanol recovered from the methanol recoverer is transferred back to methanol holding tank 402 for use in the process or otherwise disposed of.
FIG. 3 is a top-view schematic of the major elements of the system.
Most of the elements of the system sit within a drip pan 303 that is approximately 2.4 m. by 3.0 m. The drip pan traps feedstock and biodiesel that has escaped from the system, for instance during filter changes or other routine maintenance. The drip pan is approximately 0.15 m. deep. Drain 1503 communicates with a holding tank. Two shelves 103 and 203 are affixed to the drip pan and hold the various pumps 403 and filters 503 disclosed herein. Most of the components of the system shown in FIG. 3 sit in the drip pan. The drip pan has enhanced utility when the system is set up in a mobile configuration, for instance in a trailer.
In the preferred embodiment shown in FIG. 3 there are two reactors 1103 of approximately 3000 l. each. A storage tank for methoxide 1203 of about 1200 l. is provided. A first methanol recoverer 903 is provided for removing methanol from by-products of the transesterification reaction (FIG. 1, 401). A second methanol recoverer 803 is provided for removing methanol from the biodiesel wash step (FIG. 1, 801). The wash takes place in wash tank 603, which has a capacity of about 5000 l. A fuel tank 1303 is provided for supplying fuel to boiler 1403, which heats the water for the reaction, pre-treatment and methanol recovery. Compressed air tank 703 holds the compressed air that is used to actuate the diaphragm pumps and mixer wands.
The reactor is a jacketed, stainless steel tank adapted from the type commonly used to pasteurize cheese. Referring to FIG. 2, the reactor comprises a reaction chamber 1502 having a jacket 302 for circulating heating fluid, normally hot water, around the outside surface of the chamber. The hot water is produced by oil burner 1302, burning at least in part biodiesel fuel supplied 1602 from the process. The water jacket maintains the reaction temperature at about 43° C. (109° F.) The tank is fitted with an internal stirring paddle 2002 and a motor 1802 for rotating the paddle.
Referring to FIG. 6, which is a cross-section of the reactor looking down on it, the relationships of the paddle 306, the tank 106, and the water jacket 206 will be better appreciated. It will also be seen that the mixing apparatus of the reactor includes at least one baffle, for instance, 406a and 406b. The baffles promote a gentle cavitation of the reaction mixture as the mixture moves around in the reaction chamber at a comparatively low speed, thereby promoting mixing of the reactants while minimizing aeration. The baffles permit a paddle rotation as slow as 60-80 RPM--much slower than in existing art biodiesel reaction chambers. The unexpected advantage of this combination of even and thorough heat dispersion by the water jacket and the slow paddle rotation is that the transesterification reaction can employ a wide variety of low-grade feedstocks and a basic catalyst without introducing excessive turbulence and oxygen into the reaction, thereby greatly reducing or eliminating saponification and increasing the yield. The reaction can also be carried out at lower temperatures, including temperatures below the boiling point of methanol. This facilitates the retention and recovery of methanol, and reduces production costs significantly.
The use of methoxide as a reactant in biodiesel production has heretofore resulted in limited economic success because of the expense of methanol, which is lost as a waste product in the existing art. The system disclosed and claimed herein incorporates a unique methanol recoverer device and method to minimize methanol loss and reduce production costs.
FIG. 4 is a schematic summary of a methanol recoverer (designated as 1702 in FIG. 2) of the type used to recover methanol from waste fluids generated by the process. An input 304 carries methanol-laden waste fluid to spray head 504 under pressure produced by pump 404. Pump 404 is preferably an air-driven, diaphragm pump. The spray head is mounted within an interior volume of a cylindrical flash drum, the volume being bounded by the wall of the drum 104. Whilst a drum is presently preferred, other tank designs, such as an inverted cone, are also useful so long as they can be easily heated. The fluid being forced through the spray head emerges from the spray head as a spray that is evenly dispersed on the heated interior wall of cylindrical flash drum 104. Drum 104 is heated such that the interior surface is above the boiling point of methanol. A temperature of approximately 93° C. (200° F.) is preferred. The boiling point of methanol at 760 mm Hg atmospheric pressure is approximately 65° C. (149° F.) The drum is heated by hot water circulated through water jacket 204. The water is heated by heat produced by the oil burner 1302 shown in FIG. 2.
As a result of the liquid methanol being sprayed onto the heated wall of the drum maintained at 93.3° C. (200° F.), the methanol evaporates as the waste fluid flows down the wall of the drum. The methanol vapors accumulate in the volume of the drum and are captured through capture pipe 604, to which is connected vacuum pump 704, which pulls the methanol vapor out of the volume of the drum and passes the vapors into condenser 804, which is maintained at a temperature below the boiling point of methanol. The liquid methanol condensate emerges though drain pipe 904, is collected, and fed back into the methoxyamine production reaction or otherwise disposed of.
Vacuum pump 704 not only removes the methanol vapors from the drum, but by reducing the air pressure within the drum, the boiling point of the methanol is reduced, thereby facilitating the methanol evaporation and recovery.
Non-volatile components of the methanol recovery process flow to the bottom of the flash drum 104 where they are collected by drain pipe 1104 and pumped to a holding tank by means of pump 1104.
The use of a heated drum to flash the methanol has a number of advantages that are of significance to this system. The main advantage is the smaller floor space that is occupied by the present drum recoverer compared to standard heated plate flash devices. Over 2700 sq. inches of surface area can be obtained from a four foot high drum that requires only 254 sq. inches of floor space. This is particularly important for the mobile embodiment of the system. A second advantage is the comparative ease in heating the drum with hot water generated by an oil burner fueled by the product of the process.
The hydronics used to circulate heated heating fluid to the various elements is also shown in FIG. 2.
Heating fluid, preferably water, is heated in oil burner 1302 to a temperature at or above the highest temperature required by the various heated elements of the system. In the present example that maximum temperature is 93.3° C. (200° F.). Any type of heating device can be used but an oil burner is preferred so that biodiesel produced by the process can be used as fuel for the oil burner, represented by the fuel line 1602. Using product to heat the water enhances both the energy efficiency and cost efficiency of the process.
Heated water is then pumped to the water jacket 1502 of reactor 302, the water jacket of methanol recoverer 1702, and the radiator of pre-treatment tank 202. Temperatures of less than 93.3° C. (200° F.) are maintained in reaction tank 202 and reactor 302 by means of thermally controlled solenoid valves that control the volume of water flow, and hence, heat, to these elements. Such hydronics techniques are known in the field of building heating systems.
FIG. 5 demonstrates how the system can be mounted in or on a vehicle in order to provide a mobile source of electric energy. The preferred vehicle is a trailer 105, such as a standard 53-foot van-type trailer that can be pulled by a tractor rig. FIG. 5 shows how the various elements described in FIG. 3 are organized to fit within the drip pan 303 mounted on the floor of the trailer 105. These elements include: shelves 103 and 203, pumps 403, filters 503 (not shown in FIG. 5), two reactors 1103, a methoxide storage tank 1203, methanol recoverers 803 and 903, wash tank 603, fuel tank 1303, boiler 1403, and compressed air tank 703. In addition, an electric generator 205 adapted to run on the biodiesel product produced by the system is provided.
Thus, an entire electrical generating system can be easily transported to emergency sites, combat areas, under-developed areas, and the like, in order to produce electricity from feedstock provided from local sources.
From the foregoing description, the novelty, utility, means of constructing, and means of using the invention will be readily apprehended. However, the foregoing description merely represents the best mode or modes known as of the present date. It is to be understood that the invention is not limited to the embodiments disclosed above but encompasses any and all embodiments within the scope of the following claims.
Patent applications in class Containig triglycerides (e.g., castor oil, corn oil, olive oil, lard, etc.)
Patent applications in all subclasses Containig triglycerides (e.g., castor oil, corn oil, olive oil, lard, etc.)