MXPA00000158A - Method for conversion of biomass to chemicals and fuels - Google Patents

Abstract

This invention provides a method for thermally converting volatile fatty acid (VFA) salts to ketones by mixing dry calcium salts of VFAs with hot heat transfer agent in an evacuated container, thereby causing thermal decomposition of the calcium salts of VFAs to form ketone-containing vapor and calcium carbonate;and separating the ketone-containing vapor from the calcium carbonate and heat transfer agent by condensing a mixture of ketones from the ketone-containing vapor. This invention also provides a process for conversion of VFA salts, produced by anaerobic fermentation of cellulosic biomass, into liquid fuels, volatile fatty acids, aldehydes, alcohols and lactic acid.

Description

METHOD FOR CONVERSION OF BIOMASS TO CHEMICAL COMPOUNDS AND COMBUSTIBLES BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention provides a process for converting biomass to chemical compounds or useful fuels, by anaerobic fermentation of biomass and recovery of useful products from the fermentation medium. By an alternative arrangement of the process steps of the present invention, a variety of products (eg, organic acid, ketone, aldehydes, and alcohols) can be produced from biomass. These products are made from salts of organic acids (eg, acetate, propionate, butyrate, lactate) which are the primary fermentation products of fermentation.

REVIEW OF RELATED TECHNIQUE Organic acids are important chemical compounds in commerce. Historically, organic acids were produced from sources of animal fat or vegetable oil or from petrolatum sources in substantially non-aqueous systems. More recently, organic acids have been ^^ ^ ¡^ ¿identified among the most attractive products for the manufacture of biomass by fermentation. Biomass can be defined as a carbohydrate material, protein or fat composition based on animal or plant. Among the most available sources of biomass are municipal solid waste (MSW) and sewage sludge (SS). Currently, many of the expenses of public funds are used to dispose of such waste, including costs that are involved in the treatment, transportation, incineration, or abandonment of coasts or oceans. The recovery of valuable biomass products such as MSW and SS could recover the costs of elimination as well as reducing confidence in non-renewable fossil fuel resources that serve as food for the production of industrial organic acid. Fermentation, therefore, can convert renewable organic materials, now considered an expensive waste, into valuable chemical comforts. 15 However, acids are produced by fermentation in dilute aqueous solutions, and recovery of the acids in pure form involves the separation of a large amount of water. Said recovery introduces a significant operating expense in the procedure, although the physical plant required to control the large volumes of solution introduces a significant capital expense. The combination of capital and operating expenses, until now, has made the production of organic acids from diomass expensive. Therefore, there still remains a need for a procedure that combines unit operations for fermentation, The concentration and recovery of organic acids to have the advantage of potential synergies that are obtained through the integration of said procedures, thus generating an economic procedure for the conversion of biomass to products. Ketones, aldehydes, and alcohols are predominantly produced from petrolatum and natural gas, and because fossil fuels are a finite resource, it is desirable to identify procedures that use renewable resources, such as biomass. Biomass is currently practiced using maize as a supply material, however, because maize has an alternative use as food, the supply material is necessarily expensive in the manufacture of expensive ethanol product.The experimental technologies are being developed, in where extracellular enzymes, such as cellulase and hemicellulase, are added to the biomes to lignocellulosic to produce sugars and subsequently fermented to ethanol. The main challenges of this technology are to develop economic sources of enzyme and develop organisms that can ferment the variety of sugars to ethanol with high yields. The technology described herein solves the problems related to the competent biomass-based technologies by using cultures mixed in microorganisms that convert the various components of biomass (for example, cellulose, hemicellulose, pectin, sugar, protein, fat). to organic acids that are subsequently converted to •? ^ ..... - ^ fa, -. • ñfjfllrrti.rr? . ¿... - a &K; ketones, aldehydes, and alcohols using a variety of chemical steps. In addition, microorganisms produce their own enzymes, thus avoiding the need to add expensive extracellular enzymes.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a process for converting salts of volatile fatty acids, produced by anaerobic fermentation of biomass, into liquid fuels. It is an object of the present invention to provide an improved method for converting biomass to organic acids, ketones, aldehydes and alcohols. These and other objects are achieved by one or more of the following embodiments of the present invention. In one embodiment, the present invention provides a method for thermally converting the salts of volatile fatty acid (VFA) to ketones comprising the steps of precipitating the metal salts of volatile fatty acids (VFAs) from the fermentation liquor of an anaerobic fermentation, recovering and then drying the precipitated metal salts of VFAs, mixing the dry metal salts of VFAs with a heat transfer agent, preferably steel balls, glass balls or ceramic balls, more preferably hollow balls which are filled with a substance that is fused at the temperature of the thermal decomposition of VFAs, in an evacuated container, the hot heat transfer agent being sufficient to raise the temperature of the metal steel of VFAs to cause thermal decomposition, with the resulting formation of steam containing ketone and carbonate metal salt; and then separating the ketone-containing vapor from the metal carbonate salt and heat transfer agent, and recovering the liquid ketones by condensation of the ketone vapor. Preferably, the metal steel of VFAs are alkali metal or alkaline earth metal salts, more preferably, calcium salts. In another embodiment, the present invention provides a method for recovering low molecular weight aldehydes and ketones from fermentation liquor produced by the anaerobic fermentation of biomass, which method comprises the steps of: (a) concentrating the salts of volatile fatty acids ( VFAs) of the fermentation liquor produced by anaerobic biomass fermentation; (b) precipitate and dry the calcium salts of VFAs: (c) add formic acid salts; (d) mixing the dry calcium salts of VFAs and formic acid with a heat transfer agent, thereby causing the thermal decomposition of the calcium salts of VFAs to form steam and calcium carbonate containing ketone and containing aldehyde; (e) maintaining a vacuum in the container by condensing the ketones and aldehydes of the ketone-containing and aldehyde-containing vapor and removing the non-condensable vapor from the container; (f) removing a mixture of calcium carbonate and heat transfer agent from the container; and (g) separating the heat transfer agent from the calcium carbonate, reheating and recycling the rt? mi .j ^^^. ^^ i ^^ _ ^^^^^ _ ^^ JMBBii¡ «Mi - ^« ^^^^^^? MMiJM ^^^^^^^^^^^ ^^ heat transfer agent, and calcining the calcium carbonate in a lime kiln. Optionally, the separated calcium carbonate can be recycled directly to the fermenter without further processing. In yet another embodiment, the present invention provides a mixture of secondary alcohols produced from ketones obtained from precipitated calcium salts of volatile fatty acids (VFAs) produced by anaerobic biomass fermentation; drying the precipitated calcium salts of VFAs; mixing the dried calcium salts of VFAs with a hot heat transfer agent in an evacuated vessel, thereby causing the thermal decomposition of the calcium salts of VFAs to form the ketone-containing vapor, and calcium carbonate; separating the ketone-containing vapor from the calcium carbonate and the heat transfer agent by condensing a ketone mixture of the ketone-containing vapor; and finally hydrogenating the mixture of ketones recovered from fermentation liquor. Alternatively, a mixture of primary and secondary alcohols can be produced by the addition of calcium salt of formic acid to the evacuated container. In an alternative embodiment, volatile fatty acids (VFAs) can be produced by (a) the anaerobic digestion of the biomass to produce a diluted solution of VFA salts; (b) concentrating the VFA salts; (c) adding a tertiary amine of low molecular weight and carbon dioxide, causing the calcium carbonate to precipitate; (d) adding a tertiary amine of high molecular weight to the solution of step c; (e) separate by j ^^ mm distillation the tertiary amine of low molecular weight; and (f) thermally converting the high molecular weight tertiary amine / VFA complex to high molecular weight amine and VFA. Alternatively, the lactic acid can be produced by the thermal conversion of a low molecular weight amine / lactic acid complex to a low molecular weight amine and lactic acid.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of a process for converting the biomass to liquid secondary alcohol fuel (fermentation method F-A plus recovery method R-A). Figure 2 shows a top view (A) and side view (B) of a biomass fermentor. Figure 3 is a schematic diagram of a preferred arrangement of four fermenters for biomass countercurrent fermentation, top view. Figure 4 shows a side view of a single biomass fermenter with an associated counter-flow wash tank and liquid piston pump. Figure 5, subpart 1-6 shows the cycles of the liquid piston pump. Figure 6 shows a schematic representation of a fermentor and associated distillation column (fermentation method F-B).

Figure 7 shows a schematic representation of a fermentor for fermentation method F-C. Figure 8 shows a schematic representation of the recovery method R-A. Figure 9 shows a schematic representation of the recovery method R-B. Figure 10 shows a schematic representation of the recovery method R-C. Figure 11 shows a schematic representation of the recovery method R-D. Figure 12 shows a schematic representation of the recovery method R-E.

DETAILED DESCRIPTION OF THE INVENTION The process of the present invention produces low molecular weight organic acids, especially volatile fatty acids, by anaerobic fermentation of biomasses. A number of process variations are contemplated within the present invention, but all procedures have three common sections of the plant: fermentation, concentration, and recovery. A general schematic diagram of a process for producing mixed secondary alcohols is shown in Figure 1. Biomass j &g 205 first passes through a pretreatment step 210, and then is supplied in the fermentation step 220 where the pretreated biomass is converted to VFA 215 salts and undigested residues 225. The fermentation liquor containing salts of VFA 215 is transferred to the dehydration stage of amine 230, where the water is extracted, thereby concentrating the VFA salts to about 20% in concentrated steam 235. The uningested residue 224 from the fermentation step is discharged or maybe it is burned by heat of processing. In the recovery step 240, the concentrated solution of VFA 235 salts is evaporated to dryness and thermally converted to mixed ketones 245 and calcium carbonate 255. The ketones 245 can also be further processed in the hydrogenation step 250 where they are hydrogenated with hydrogen gas 275 using a suitable catalyst (e.g., Raney nickel) to produce mixed alcohols 265 useful as fuels. Alternatively, if a stream of concentrated acid is the desired product, the concentrated solution of VFA 235 salts can be processed as described below "releasing" the acids from the salt solution. The resulting acid stream can be used directly, instead of processing it through the steps of thermal decomposition and hydrogenation. Calcium carbonate 255 can be recycled to fermentation stage 220 to neutralize acids produced by fermentation, or burned in lime kiln 260 to produce lime 285 that can be used in pretreatment stage 210. Alternatively, instead of adding calcium carbonate 255 to the fermenter 220, the lime 285 can be added in order to maintain a higher pH in the fermenter 220. The volatile fatty acids as contemplated by the invention are saturated aliphatic carboxylic acids with relatively low carbon number, such as acetic, propionic acids and butyric (carbon number 2-4). As contemplated, volatile fatty acids include all aliphatic carboxylic acids produced by "acid forming" bacteria under anaerobic fermentation conditions. Said carboxylic acids come to a relatively low temperature, and are therefore designated as "volatile". Table 1, which shows the boiling points for normal alkylcarboxylic acids at atmospheric pressure, is given below: TABLE 1 Carbon No. Acid B.P. (° C) 2 acetic 118 3 propionic 141 4 butyric 164 5 valeric 184 6 caproic 202 7 entritic 223 8 caprylic 238 9 pelargonic 253 10 capric 268 Recovery of chemical compounds and fuels The description of this patent describes a family of procedures that is based on a common method of biomass conversion by anaerobic fermentation. The procedures are divided into three sections: fermentation, concentration and recovery. The variants in each section of the procedures are described in more detail below. Each of these sections of the general procedure has been independently tested, some at large scales. Further optimization of the general procedure can be achieved by particular biomass supply materials and environmental situations (eg, near sources of, or uses for, excess processing energy) based on the considerations described herein. Said optimization is easy for the person skilled in the art. The fermentation, as described herein, can be carried out by a pure culture of microorganisms or by a mixed culture. Mixed culture fermentation is described below in the F-A fermentation method, advantageously using harvested acid-forming bacteria. The F-B fermentation method produces ethanol and organic acid salt using pure or mixed cultures of bacteria, one of which must be cellulolytic. The F-C fermentation method uses pure cultures of lactic acid forming bacteria. Although the cultures of such alternative fermentations are different, the various methods may use similar starting materials, similar fermenters, and the products may be recovered by similar methods (recovery methods A-E), except where specifically indicated otherwise. Three types of fermentations are described in this: ^^^^^^ jmH i ^^^^^^^^^ ßiÉÉ ^ Products alcohol acids Fermentation Acetic Propionic Butyric Lactic Ethanol F-A + + + - F-B + + F-C - - - + The fermentation products are present in dilute aqueous solutions. Generally, there are around 30 kg. of water per kg. of product, and said amount of water must be removed to recover and purify the fermentation products. The concentration of organic acids produced by fermentation (or their separation from water in the fermentation medium) can be achieved by a variety of different operations, including distillation, multi-effect evaporation, vapor compression, heat pumps, reverse osmosis , and extraction of the VFAs from the water. The section of the particular unit operation will be made in accordance with the guides provided herein, in view of the particular supply materials, in desired product, and environmental situations (e.g., near sources of, uses for, processing energy in excess). Said optimization is easy for the person skilled in the art. The recovery of the inorganic salt VFA can be achieved through (R-A recovery method) thermal conversion of VFA salts to ketones; (recovery method R-B) displacement of the inorganic cation by tertiary amines of low molecular weight, followed by thermal decomposition m %%.,. of the amine carboxylate to liberate the acids and regenerate the amines; (recovery method R-C) successive replacement of the inorganic cation by tertiary amines of low molecular weight, and then by tertiary amines of high molecular weight, followed by thermal decomposition of the amine carboxylate; (R-D recovery method) displacement of the inorganic cation by tertiary amines of high molecular weight, followed by the thermal decomposition of the amine carboxylate to liberate the acids and regenerate the amines; (recovery method R-E) displacement of the inorganic cation by ammonia, then by tertiary amines of high molecular weight, followed by the thermal decomposition of the amine caboxylate to liberate the acids and regenerate the amines. The first method produces ketones while the other four methods produce acids. The various recovery methods employ the chemical compounds listed below: Recovery Product PM under high PM NH3 3 ° Amine 3 ° Amine R-A Ketones - - R-B acids + - R-C acids + + R-D acids + + R-E acids + + The following diagram shows the fermentation procedures that can be combined with the recovery procedures: - / OUII I MCI ll? JO UC ICI I I IC; i i i i MCI ILUO UO 1 cv R-A R-B R-C R-D R-E F-A + + + + + F-B + + + + + F-C - + - - - The method of the present invention is particularly useful as part of a process for producing ketone or alcohol fuel from biomass. Such products are made from calcium salts (eg, acetate, propyanate, butyrate) which are the primary fermentation products of anaerobic biomass fermentation. A number of process configurations can be used, and suitable process components will be described in terms of fermentation, concentration and recovery.

Pre-treatment and fermentation Fermentation is generally an effective way to convert the biomass supply materials of organic acids. The cellulosic biomass is particularly attractive for this purpose. Rapier (MS Thesis, Texas A &M Univ., College Station, 1995) has determined that the mixture of 80% municipal solid waste (MSW) and 20% sewage sludge (SS) provides the optimal combination of energy and nutrients for a mixed culture of acid forming microorganisms; therefore, this relationship was used in B ^ said study. However, sources of cellulosic biomass generally need some degree for optimal conversion by fermentation. Numerous treatments have been developed to promote the enzymatic digestibility of lignocellulosic biomass including: physical treatments (eg, ball milling, two-roll milling), chemical (eg hydrolysis of dilute acid, alkali), physico-chemical (eg. , steam explosion, ammonia fiber explosion), and biological (for example, white decomposition fungi). The alkaline treatment is particularly suitable for acid-producing fermentation, because the acids produced in the fermenter will neutralize the alkali, thus allowing recovery of the treatment agent. Of the various alkalis that are effective (eg, sodium hydroxide, ammonia), lime is attractive due to its low cost and compatibility with other processing steps. When compared with other alkali, the literature on lime treatments is relatively scarce. Most studies have been developed by scientists in animals that seek simple treatments at room temperature to boost the digestibility of ruminants. Because the treatment temperature was low, their results were poor; leading to the general convention that lime is not as effective as other alkalis. However, when optimizing the reaction temperature and other conditions, the lime can be a very effective treatment agent. Recent studies of lime treatment use extracellular enzymes to hydrolyze the biomass shows that, compared to untreated biomass, the treated biomass Ja with lime has an enzymatic digestibility barely ten times greater. Due to its low lignin content, the boiled biomass requires only lime treatment. However, due to its high lignin content, the woody biomass requires the addition of oxygen to partially oxidize the lignin and remove a part of it from the biomass. In addition, woody biomass requires more severe time and temperature. The treatment of lime hardly boosts the ruminant digestibility of biomass twice. In addition, the digestibility in the ruminant is greater than that achieved with extracellular enzymes. This result suggests that an industrial procedure based on a mixed culture of microorganisms (analogous to the rumen microfluora) may have advantages over the procedure that are based on extracellular enzymes. In a particular process example, the biomass (e.g., pomace, grass, municipal solid waste) is placed in a tank, and heated water is added from a recycle stream. The lime is added to the biomass (typically 0.1 g of Ca (OH) 2 program of dry biomass). The lime / water / biomass suspension is wiped for 1 to 24 hours while stirring. If the biomass particles are slightly rough (eg, greater than about 20 mesh), they can be simultaneously bombarded through a colloid mill (not shown) to crush them. However, it is preferred that the biomass be crushed to a suitable particle size prior to the addition of lime. When the rinse is complete, the lime water is drained from the solid suspension. As a precaution to prevent excessive alkaline pH in the fermenter, ^ at immmas ^ k ^ more lime can be removed by leaching the biomass with recycled water. (Two containers can be used for rinsing and leaching, or such procedures can occur in the actual container). Alternatively, instead of removing the lime, the reaction site can be neutralized with carbon dioxide, from the fermenters to form the calcium carbonate. The fermentation can be carried out in liquid or semi-solid processes, in a single large fermenter, or a number of fermenters connected in parallel or in series. The fermentation can be carried out by batch or in continuous or semi-continuous mode. In a fermentation mode (F-A), the biomass treated with lime is slowly added to the fermenter, where the anaerobic organisms convert the biomass to organic acids. These organisms are a mixed crop that can be obtained from several sources (for example, cattle rumen, soybean, mixtures, or anaerobic sewage digesters). These produce a variety of products, but mainly acetic acid with lower amounts of propionic and butyric acids. The ratio of said products depends on factors such as microbial population, pH, and temperature. Acetic acid dominates at temperatures above 55 ° C. As organic acids are formed, the pH is reduced. Typically, calcium carbonate or lime that was not removed after the pretreatment process is used to neutralize the acids by calcium salt formations. The pH can also be regulated by the addition of more lime or calcium carbonate. Generally, a pH of about 6.2 is preferred, but the pH may vary from about 5.5 to 7.0. Because asepsis is not required for the fermentation of biomass mixed culture (that is, the supply and containers should not be sterilized), recycling can be used without risk of contamination. The fermenters can be operated in a continuous mode. The cells can be recycled to maintain a high concentration of cells in the fermenters that can reduce the residence time required. The concentration of solids in the fermenter will usually be high (around 10-25%) to make the most efficient use of the fermenter volume. If all the carbohydrates in biomass are converted into organic acids, the concentration of organic acid salts will be around 8-20%, which is much higher than what can be tolerated by microbes. To avoid such a problem, the liquid can be constantly removed from the fermentors to maintain the organic acid salt concentration below about 3.4. Several methods can be used to separate solids from liquid (eg, filters, decanters). For example, the suspension can be pumped through a hydroclone in which the centrifugal force of the turbulent fluid separates the solids from the liquid. The liquid will still have some particles, because the separation is not perfect, therefore, it can also be clarified by filtering through a sand filter, or similar device. When the sand filter is cleaned by backflushing, the solids simply return to the fermenters for further conversion to organic acids.

If a series of fermentors is used, the biomass will travel through the fermentor train essentially in a piston-type expense. The carbohydrate content of the biomass will be reduced as it is converted to organic acids. In the long run, the solids will consist mainly of lignin, calcium carbonate and cells. The cells can be coated separately drunk to settle more slowly in the undigested calcium carbonate and solids. The remaining solids (lignin and calcium carbonate) can be burned in a lime kiln to provide process heat and convert calcium carbonate to lime. In an alternative configuration of fermentation mode, a series of semi-solid fermentations has been operated using horizontal, stainless steel cylinders, each with a center axis having finger-like projections extending close to the wall of the cylinder which "molds" "The contents of fermenter as the shaft rotates. The individual fermenting cylinders are operated in series with solids flowing countercurrent to the liquid, and solid / liquid separation was achieved by centrifugation of the contents of the fermenter and decanting of liquid in an anaerobic layer. This countercurrent operation allowed high VFA concentrations to be generated in the fermenter that receives fresh, highly reactive solids. It also allowed the high conversion due to inhibition to be low in the fermenter that receives the fresh liquid. When compared to the rumen fermentations that typically stop only a couple of days, the residence times of the fermenter in ^^ g ^ | the previous example were significantly longer due to the inhibition of the high concentration of the VFA (20-35 g / L against 8-10 g / L), because the fermenters of industrial scale can be very economical, the long time of residence does not impose a severe economic penalty. The time scales and procedure are similar to those for mixing; in this way the procedure can be observed as an anaerobic mixing operation. The volume of the fermenter is proportional to the liquid residence time while the conversion is proportional to the residence time of the solids. By allowing the concentration of VFA and conversion to increase, conversions were obtained representing 85% of the maximum possible digestibility and a MSW / SS mixture. In yet another alternative for such a fermentation mode, the fermentation section of the process according to the present invention will include more than one fermentation vessel, arranged for the countercurrent flow of the biomass and the fermentation liquor. Said provision is described in more detail in the application of E.U.A. with serial No. 08 / 688,051, issued July 31, 1996, entitled "Method and Apparatus for producing Organic Acids". Said arrangement includes a plurality of fermenting vessels, a countercurrent washing system, and a solids transfer system. The preferred form of the fermenting vessel is the trunk of a pyramid. The fermenter is constructed by digging a ditch for excavation of the earth. The inclinations of the wall of the fermenter are preferably of a "natural angle" that is formed when the crushed stone is piled and ^? (around 30 ° C). The fermenter wall is lined with a geomembrane, crushed stone, and an abrasion resistant liner. The upper part of the fermenter is covered to prevent gases escaping into the atmosphere. The construction of the individual fermenting tanks is described in more detail in the application of E.U.A. with serial number 08 / 688,051, entitled "Method and Apparatus for producing Organic Acids", issued July 31, 1996, incorporated herein by reference. According to a preferred embodiment of the present invention shown in Figure 2, the liquid circulation provides agitation for the fermentor. The fermenter contents are a biomass / water suspension 334 with a liquid layer 335 at the top. A series of pumps 331 along the edge of the fermenter eject the liquid from the upper layer and pump it back into the fermenter through a distributor tube 336 located at the bottom. As the liquid flows through the biomass, eliminates bags of acid concentration that can inhibit the digestion of biomass. To create a certain mixture, the liquid must preferably circulate through the fermenter around a mixture every 12 hours, controlled by the circulation pumps 331 of the fermenter. In a related, preferred embodiment, the fermentation method of the present invention provides liquid piston pumps for transporting solids through the fermenting complex. This mode does not require pumps to transport solids, thus eliminating excessive expense and maintenance problems. The present invention, even in another • £ &ét | preferred embodiment, it also provides an economical counter-current washing system. Figure 3 shows an aerial view of a preferred mode having 4 fermenters CSTR 111. The tanks together with the outer rim are countercurrent wash tanks 121. At the end of the countercurrent wash tanks are the liquid piston pumps 131. The fresh biomass 141 is subjected to pretreatment and introduces the highest concentration of product to the fermenter 111a. When the biomass is removed from the fermenter 111a, it is washed in the countercurrent wash tank 121a to remove the product and pass to the next fermenter 111b. In Figure 3, the flow of biomass is against the clock hands. In the long run, as it passes through all the termenters, the biomass is digested. The fresh water 151, used to wash the discarded solids, flows clockwise through the countercurrent wash tanks 121 until it is finally collected as the concentrate product 161. In addition, the liquid 171 is decanted from the top of a fermentor and pumped to the adjacent fermenter to increase the acid concentration. In an alternative embodiment, the liquid exiting from the counter-current wash tank can be directed towards an adjacent fermenter, instead of an adjacent counter-current wash tank. Said case, the washing water supplied to the countercurrent washing tank can be taken from an adjacent fermenter, instead of an adjacent washing tank.

Figure 4 shows a side view and a fermenter 111, a countercurrent wash tank 121, and a liquid piston pump 131. The countercurrent wash tank consists of a series of agitated zones 122 and quiet zones 127. The agitation is It manages an upward flow of the liquid 125. The solids flow in one direction and the liquid flows to the other. At the end of the counter-current wash tank is a liquid piston pump 131. The liquid piston pump is a three-tank unit (See figure 5, which shows the three-tank equipment at successive time points). At any given time a tank (by gravity) is filled with suspension 134, one tank is partially filled with liquid 135, and the other is released by draining the suspension 134 by pumping liquid 135 towards the top using the pump liquid 136. When the cycle is completed, the function of each tank is rotated. The main advantage of this system is that solid transfer pumps are not required to transport the solids between the fermenters; In this way, an economic method to achieve countercurrent flow has been provided. Each fermenter 111 requires a countercurrent wash tank 121. The solids will occupy about two thirds of the tank with the remaining one third of wash water. The preferred configuration of the tank is the trunk of a rectangular pyramid. A single washing step typically requires the replacement of water within the solids with an equal volume of "new" water. Preferably, there are three stages of washing per fermentor, except for the last fermenter, which has ten stages to expel the last traces of J ^ ^ ^ acid, and each stage requires a pump for washing solids, for a total amount of 19 (3 x 3 + 10) pumps. However, all these are clean liquid pumps instead of more expensive suspension pumps. Figure 6 shows an alternative fermentation method (F-B), in which acetic acid and ethanol can be produced simultaneously by thermophilic bacteria. The cellulite organism Clostridium thermocellum has a high cellulase activity that can convert hexoses to ethanol and acetic acid in approximately equal amounts. Because it has said organism is unable to use pentose sugars, the Clostridium thermosaccharolyticum, C. thermohydrosulfuricum, or Thermoanaerobacter ethanlicus should be cultivated with C. thermocellum. The biomass 405 is supplied to the fermenter 420 producing an aqueous stream 415 which contains approximately equal amounts of ethanol and acetic acid. Ethanol 435 can be recovered from distillation column 430, while acetic acid 445 can be concentrated and recovered by the method of the present invention. If the organisms are more tolerant to acetate ions than to ethanol, some of the lower parts of distillation column 455 can be recycled so that the fermenter allows the acids to accumulate at higher concentrations. Lime 285 'or calcium carbonate 255' is added to the fermenter to keep the pH close to neutrality. Said procedure requires asepsis, because a pure culture (or coculture) is being maintained. For some systems, treatment with lime may be sufficient to sterilize biomass and water. However, if contamination is a problem, it is possible to sterilize the biomass by direct steam injection. The water can be sterilized using conventional sterilization equipment (for example, countercurrent heat exchangers with a high temperature maintenance section). The fermenter can be operated in a batch mode or continuous mode, however, the batch mode is prone to have fewer contamination problems. Figure 7 shows yet another alternative fermentation (FC) method in which an aqueous stream containing lactic acid 465 can be produced from a variety of sugars (e.g., whey lactose, sugar cane sucrose or sugar beets). sugar, glucose of starch hydrolysates, sulphite liquor pentoses, mixed sugars of cellulose hydrolyzate) aqueous solution 415 '. The organisms capable of carrying out the fermentation are generally removed from the genera Lactobacillus, Streptococcus, Pediococcus and Rhizopus. As the acid is produced in fermenter 440, lime 285"or calcium carbonate 255" is added to maintain a pH of 5-7.

Concentration A common key feature for the process family is the concentration section of the plant where the non-volatile fermentation products (eg, calcium acetate) are separated from the water. The fermentation products are present in dilute aqueous solutions. Generally, there are about 30 kg of water per kg of product. Said large amount of water can be removed to recover and purify the fermentation products. The concentration of VFA salt leaving the fermentor is about 25 to 45 g / l, or about 25 to 40 parts of water per part of VFA salt. The pKa of the VFAs is around 4.8, so that at the pH of the fermentation (~ 5.8), only about 10% of the FMDV is present as a free deionized acid; the rest is ionic salt. Process steps that can be considered to concentrate the VFAs (or separate them from the water in the fermentation medium) include distillation, multiple effect evaporation, vapor compression, heat pumps, reverse osmosis, and extraction of the VFAs from the water. Distillation is only useful if the product is more volatile than the solvent. For non-volatile products in an aqueous fermentation medium, the water will pass to the top of the distillation column and will require huge amounts of latent heat to vaporize the water. Salt and free deionized acid are less volatile than water, so distillation is not a preferred separation technique. Multi-effect evaporation techniques generally couple evaporators. The heat (usually from the process steam) is placed on the first effect that vaporizes the water. The water vapors produced in the first effect are thermally contacted with the liquid at a lower pressure in the second effect. When the vapors are condensed, they cause an equal amount of water to evaporate from the second effect. These water vapors, in turn, are contacted with the third effect that vaporizes more »Jg ^ igSS» water, etc. The final effect vapors are condensed by rejecting the heat to cool the water. Only the first effect requires the heat input of the process steam, even the same amount of water is produced in each effect. Considering that there are around 30 kg of water per 1 kg of fermentation product, a four-effect evaporator could require that 7.5 kg of water be evaporated in the first effect. Even the energy cost of a quarter of water evaporation (ie, in a four-way evaporator) can be very costly in several modes of operation, because it represents about 10% of the selling price of several such products of fermentation. Steam compression is carried out using a compressor to create a vacuum in the fermentation liquid that causes it to boil. These low pressure vapors are then compressed to a slightly higher pressure. These higher pressure vapors are in thermal contact with the liquid. When these are condensed, they supply the latent heat necessary to evaporate more water from the fermentation liquid. Only a single heat exchanger is required to transfer the heat from the condensing vapors to the boiling liquid. This approach requires very large compressors, because the specific volume of water vapors is very large. In the same way, high quality energy must be provided in the form of work (for example, electricity, arrow work), so that the above is not economical.

Heat pumps are similar to the vapor compression approach, except that the alternate fluid (eg, ammonia, Freon) is compressed in place of water. A smaller compressor can be used, because such alternating fluids have a specific volume much lower than the low pressure vapor. Unfortunately, this method requires two heat exchangers (for example, condensation of ammonia for boiling, fermentation of the liquid and boiling of ammonia for condensation of water vapor), so that the irreversibilities, associated with heat transfer are usually very large, said approach also requires high quality energy in the form of work. Membrane techniques (eg, reverse osmosis, electrodialysis, water separation electrodialysis, carrier-mediated transport membranes) should also be considered, but the cost of the membranes makes them prohibitive. In reverse osmosis, the fermentation liquid is pumped to around 55 atm and contacted with a membrane that passes selectively through water, but rejects the salt ions. Because the salt ions are retained behind the membrane, they are concentrated. This method uses high quality energy in the form of work (for example, electricity or arrow work). The membranes are easily soiled and should be replaced approximately every 2 years. Similarly, there are few economies of scale associated with membrane procedures, because the membrane area increases linearly with the capacity of the plant. g ^ g Playne (in Moo-Young et al., eds., "Comprehensive Biochemistry," Pergamon Press, New York 1985, Vol. 3, pp. 731-759) describes various techniques for recovering VFAs from dilute aqueous solutions . Some proposed methods employ immiscible solvents (eg, tributylphosphate, trioctylphosphine oxide, high molecular weight amines) that react with free deionized acid and extract it from the broth. For the extraction of the solvent to be effective, the pH of the fermentor must be acidic (4.8 to 5.2), which severely inhibits the microorganisms. Alternatively, if the fermentation is operated close to neutrality, the fermentation broth can be acidified with mineral acids (which generate waste) or carbon dioxide (which requires high pressures). An approach for extracting the fermentation product from water is described in the U.S. Patent. 4,444,881. The calcium salt (eg, calcium acetate) in the fermentation broth is contacted with a tertiary amine (eg, tributylamine) and carbon dioxide. The insoluble calcium carbonate precipitates leave the tributylamine acetate in solution which is then extracted using a suitable solvent (for example, chloroform). The chloroform is then removed by evaporation of the tributylamine acetate. Upon heating, tributylamine acetate is decomposed into tributylamine (which is recycled) and acetic acid. The tertiary amines are preferred over the primary or secondary amines because the latter tend to form amides in the heating, which represents a loss of product. The extraction of tributylamine acetate from the liquid must be very complete because the water will be recycled to the fermenter. Tributylamine not recovered will be consumed by the fermentation organisms and will be lost. Said loss could be reduced by the absorption of the residual tributylamine acetate in the activated carbon, however the above requires a costly additional step. The precipitated calcium carbonate must be completely washed to recover tributylamine. The enormous quantities of solvent (for example, chloroform) must evaporate. The distribution coefficient is apparently less than 1, so that the tributylamine acetate that was found in the water is now present in an even greater amount of solvent. The salts (for example potassium, phosphorus) present in the biomass of the supply material have no way of leaving the fermentation system. These will accumulate at inhibitory levels, so a purge current will be required. Instead of extracting the salts from the water, the water can be extracted from the salt using secondary or tertiary amines with 5 to 6 carbon atoms per molecule. Prior to extraction, the fermentation broth is first contacted with lime to raise the pH to around 11.5. At said pH, the minerals are precipitated as well as the carbohydrate polymers. The precipitate is removed (for example, by decanting) so that it does not interfere with the water extraction process. The amine dehydration system of the present invention (see, for example, Figure 1) exploits the interesting properties of the secondary and tertiary amines of low molecular weight. Amines are substantially not miscible in water. At low temperatures (eg, 40 ° C), the water is highly soluble in the amine, but when the temperature rises to about 20 ° C (e.g., at 60 ° C), the water becomes substantially insoluble in water. the amine. By contacting the thin amine of water with fermentation broth, the water is selectively absorbed leaving behind the salt. By using the countercurrent contact with sufficient amounts of amine (approximately 5 times the amount of amine as the fermentation broth) enough water can be extracted to increase the salt concentration in the fermentation broth of about 25 to 45 g. / l (for example 2.5 to 4.5%) around 200 g / l (ie 20%). The water-rich amine that contains the water The extracted fermentation is then heated in a counter-current heat exchanger and sent to a separator in which the steam is injected to raise the temperature to around 20 ° C-25 ° C. This causes the water to separate from the amine that is then decanted. The latent heat is required to cause phase separation of water and amine. Because the temperature in the separator is relatively low (eg, 60 ° C), it provides a convenient place to usefully reject waste heat from the other sections of the plant. The extraction of water using amines was explored in the 1950s and 1960s as a method for water desalination. Although the reverse osmosis is the current preferred method for water desalination, the extraction of water from the fermentation liquid seems to be preferable for the concentration of fermentation broths. The extraction will vary approximately with the 0.6 capacity energy while the reverse osmosis will vary almost linearly. ^^^^^^^^^^^^^ __ ^ lMil ^ _¡? üH ^ M ^ _ ^^^ ail ^. ^^^^^^^ H Therefore, the extraction will achieve economies of scale in large plants but not reverse osmosis. Reverse osmosis is very sensitive to fouling of the membrane, while the same does not happen with extraction. It will be difficult to separate all the solids, (for example, lignin, cells) to satisfy the cleaning requirements of the reverse osmosis. To produce potable water with a low salt content, the extraction procedures require a reflux stream of water, so that the dismantling section and the rectification section are included in the extraction column. However, the recovery salts of the fermentation broths do not need a rectification section because any salt in the extracted water is simply recycled for the fermenters. Because the extraction amines are not completely immiscible, they are present in the product water at about 5% concentration. Said amines must be removed by separation. The separation efficiency is low at neutral or acidic pH (where the amine is an ionized salt) and is high at an alkaline pH (where each amine is not ionized). It was also not possible to adjust the pH to sufficiently alkaline conditions when the water was made to take, however it is entirely possible in the recovery of the biomass fermentation products. Said amine dehydration process is described in more detail in the application with serial No. 08 / 885,841 issued June 30, 1987, entitled "Recovery of Fermentation Salts from Dilute Aqueous Solutions", incorporated herein by reference in its whole.

Recovery / Convention The salts of VFAs are optionally precipitated from the concentrate obtained from the fermentation liquor, and which is dry. Recovery of the desired product from the concentrate or dry salt can be by any of the following procedures. In a particular embodiment (R-A recovery method), the products are low molecular weight ketones produced by a process that thermally converts the salts of volatile fatty acids (VFAs) into ketones in or in yield. In the metal salts of VFAs, the anion portion of the salt is provided by the VFAs, while the cations are usually alkali metal or alkaline earth metal cations. Preferred salts include, for example, lithium, sodium, potassium, magnesium, calcium or barium salts, or a mixture of two or more of said salts. Figure 8 shows a schematic representation of the recovery method R-A. The VFA salts 235-8 of a dehydration system (eg, an amine dehydration system 230 in Figure 1) should have a concentration of about 20%. The pH of the concentrated salt solutions of the amine dehydration system is alkaline. To avoid undesirable reactions in the 545 thermal converter, the pH can be adjusted down by the addition of carbon dioxide. Said acid salts are introduced into a multi-effect evaporator consisting of steam de-entrainers 500, heat exchangers 505, and circulation pumps 510. Three effects are indicated in FIG. 8, of which less or more than these effects depending on economic considerations. The steam de-entrainers operate successively at lower pressures with steam de-entrainer 500a operating at a higher pressure and steam de-entrainer 500c operating at lower pressure. The steam from the process is supplied to the heat exchanger 505a, which produces vapors that are de-entrained in the steam de-entrainer 500a are supplied to the heat exchanger 505b. This procedure is repeated in the subsequent effects. The vapors generated in the lower pressure effect (steam de-entrainer 500c) are directed to an earlier stage in the process (e.g., amine dehydration system 230 in FIG. 1) to provide the latent heat necessary to separate the water of the amine. The steam de-entrainers 500 are divided into two zones, one agitated (shown in the upper part in FIG. 8) and the other at rest. The liquid in the stirred zone is circulated through the heat exchanger and returned to the agitated zone. As the vapors are removed, the salt precipitates and settles in the resting zone. The precipitate suspended in the resting zone is pumped through a solids separator 515 (eg, filter, cyclone, or centrifuge) and the expensive solid-free liquid is returned to the agitated zone of the steam de-entrainer. The salts recovered from the solids separator 515 are sent to the dryer 550, which is agitated by the motor-driven propeller 570 560. The saturated steam from the dryer 550 is driven by the blower 530 through a heat exchanger 540, which superheats the vapors. The steam ^. ^^^^^ .. ^ Mtaii ^ MÉÉM ^ ÍÍÉ ^^ _ ^^ ttí ^. ^^^ É? superheated is returned to dryer 550, where sensible heat provides the latent heat necessary for the water to vaporize from the wet salt. Most of the water vapor is circulated through the dryer 550, while a small portion, in which it is evaporated from the wet salt, is removed from the dryer 550 and sent to an amine dehydration system to provide the latent heat necessary to separate the water from the amine. The dry salt 535 enters the thermal converter 545, which is described in more detail in the application with serial No. 08 / 885,774, issued on June 30, 1997, entitled "Thermal Conversion of Volatile Fatty Acids to Ketones", and incorporated herein by reference in its entirety. The ketones 245-8 are recovered as a product or sent to a hydrogenator for conversion to secondary alcohols. Current 255-8 contains mainly calcium carbonate, but may also contain soluble minerals that can be purged from the system by removing a side stream, dissolving a portion of it in water, using the 575 mixer, and removing the calcium carbonate. insoluble using the 580 solids separator (for example, felt, cyclone, or centrifugation). The soluble minerals will be found in the water and can be purged from the system. Most of the stream 255-8 will be sent to the lime kiln or directly to the fermenter in the procedure shown in Figure 1. In an alternative embodiment, the process according to the present invention can be used to produce aldehydes by inclusion of format of calcium (or other salt of metal format) with salts of VFA & - introduced into the reaction chamber. The above will usually produce a mixed aldehyde / ketone product that can be separated by distillation. Alternatively, the mixed aldehyde / ketone product can be hydrogenated to produce mixed primary and secondary alcohols.

Hydrogenation Ketones may be economical enough to be used as motor fuel. Because ketones are not currently accepted to be mixed with fuel, they must first be hydrogenated. The above is easily achieved at room temperature and at ambient pressure by contacting the ketone using a Raney nickel catalyst. The reaction proceeds more quickly at higher temperatures, but the equilibrium becomes less favorable. The liquid ketone product can be converted to alcohols by hydrogenation. From the typical VFA compositions in the fermenter, four ketones (2-propanone (acetone), 2-butanone, 2-pentanone, and 3-pentanone) comprise about 90% of the expected product. The hydrogenation can be carried out at 1 atm of total pressure and near room temperature, using a Raney nickel catalyst. When comparing the hydrogenation rates of the four ketones at 40 ° C, they are all very similar and differ by a factor of two. The reaction rate increases linearly with hydrogen pressure and catalyst concentration with the proviso that the reactor is not limited in mass transfer. - "" "* - - ~ ^^. ~. * iMfc» «. and ^^ Hydrogen is also derived from reformed natural gas, an abundant domestic energy resource.In large-scale production, hydrogen costs almost the same as gasoline per unit of energy, so that there are no economic penalties associated with its use.The ketone can be observed as a carrier of hydrogen that avoids the need for high pressure tanks to store hydrogen gas in automobiles.

Acid Recovery Figure 9 shows a schematic representation of the R-B recovery method that allows high-boiling acids (eg, lactic acid) to be "released" from the calcium salts of the acids. A solution of acid salt 235-9, such as that of the amine dehydration section 230 in Figure 1, which is about 20% acid salt with the remaining water, flows into contactor 600 which is contacted with the salt solution of acid with a stream 602 rich in carbon dioxide and a tertiary amine 615 of low molecular weight, preferably the same amine used in the amine dehydration system 230 (see Figure 1). A lower water content is possible if the solution of the acid salt is further dehydrated using multi-effect evaporators. The tertiary amine 615 of low molecular weight, the acid salt solution 235-9, and the carbon dioxide-rich gas 602 are agitated by the mixer 605 to ensure good contact within the species. A reaction occurs in which the calcium in stream 235-9 reacts with the carbon dioxide in stream 602 and precipitates as calcium carbonate, allowing the amine to form an amine / acid complex. CaA2 + CO2 +2 R3N + H2O - CaCO3 + 2R3NHA To ensure that a small amount of volatile tertiary amine, low molecular weight comes out of contactor 600, the contact trays can be placed above the mixer. The gas jet exits in stream 610. The precipitate of calcium carbonate is removed in the solid separator 620 (eg, filter, cyclone, or centrifuge). Using the solids separator 625, the wash water 637 is removed from the amine / residual acid complex. Optionally, the solid separator 620 and 625 can be the same piece of equipment; for better understanding, the filtration modes and wash operation modes are shown in figure 9 using the following pieces of equipment. The washing calcium carbonate 626 can be sent to the fermenter (for example, 220 in Figure 1) or a lime kiln (for example, 260 in Figure 1) with the proviso that the amine content is sufficiently low. . If necessary, the volatile amine can be removed from the calcium carbonate using the dryer 680. The engine 685 rotates the thruster 690 to ensure good contact between the superheated steam in the solid calcium carbonate, the outgoing steam can be sent to the system of amine dehydration (eg, 230 in Figure 1) to provide energy to the phase water leaving the amine. If the above reaction is carried out with an amount of water, the water can be removed in stream 629 using a 630 multi-filter evaporator. Three effects of Figure 9 are shown, but less or more effects can be employed depending on the economic aspects. Any amine in streams 633 and 634 can be removed from the water by separation. Alternatively, to promote energy efficiency, streams 633 and 634 can be returned to the amine dehydration system (eg, 230 in Figure 1), with the proviso that the same amine is used in both systems. The vapors leaving the multi-effect evaporator 634 can be used to provide the latent heat necessary for phase separation of the water and amine in the amine dehydration system (eg, 220 in Figure 1). The liquid stream 632 leaving the multi-effect evaporator 630 may contain small amounts of water that can be removed in the distillation column 635. The distillation column 635 is operated below the temperature at which the complex decomposes. amine / acid. Superheated steam (or an inert gas) is added to the bottom of the column to promote good mass transfer in the trays. By ejecting a side stream of liquid from the trays in the column (not shown in Figure 9), and supplying heat using a heat exchanger, the water will evaporate leaving the amine / acid complex mainly in the liquid phase. The condenser 638 allows reflux to be added to the distillation column to ensure that little amine is left at the top. To promote the efficiency of energy, the latent heat of the 638 condenser can be rejected to the dehydration system of U ^ = n amine (eg, 230 in Figure 1). The distillation column 635 can be removed if the water can be tolerated in the downstream processing steps. The lower portions of the distillation column 635 are preheated in the countercurrent heat exchanger 640 and introduced to the reactive distillation column 645. Said column is operated above the decomposition temperature of the amine / acid wherein the following occurs reaction R3NHA - R3N + NA The volatile low molecular weight tertiary amine leaves the top of the column. The condenser 639 allows reflux to be added to the distillation column to ensure little acid exit from the top. To promote energy efficiency, the latent heat of the condenser 639 can be expelled to the amine dehydration system (eg, 230 in Figure 1). The condensed amine is recycled to contactor 600. The acid 643 exiting the bottom of the reactive distillation column 645 is cooled in the countercurrent heat exchanger 640 and sent to the multi-effect evaporator 650 to remove residual salts from the reactor. acid product 670. The condenser 665 condenses the vapors of the lower pressure effect. To promote energy efficiency, latent heat can be expelled into the amine dehydration system (for - «for example, 230 in Figure 1). Depending on the acid, it may be necessary to operate a vacuum multi-effect evaporator 650 to avoid thermal decomposition. During the pumping of the acid / salt suspension using the 660 pump, the residual salts are separated using the solids separator 655. If necessary, a small amount of acid (eg, sulfuric acid) can be added to ensure that all salt cations (eg, K +) have an anion attached (ie, SO 2"). Due to its relative simplicity, the RB recovery method is a preferred method, with the proviso that the boiling point of the acid is higher than the thermal decomposition temperature of the amine / acid complex By altering the pressure in the reactive distillation column 645, it is possible to adjust the boiling point and the decomposition temperature.An alternative modality is shown in the figure 10 (RC recovery methods), which allows low-boiling acids (eg, acetic acid) to be "released" from the calcium salts of the acids. acid salt 235-10 of the amine dehydration section (eg, 230 in Figure 1) is preferably about 20% acid salt with the remaining water. A lower water content is possible if the acid salt solution is further dehydrated using multi-effect evaporators. Acid salt solution 235-10 flows into contactor 600-10, which contacts the acid salt solution with the carbon dioxide rich stream 602-10 and a low molecular weight tertiary amine 615-10, preference - jg ^ X the same amine used in the amine dehydration system (for example, 230 in Figure 1). The low molecular weight tertiary amine 615-10, the acid salt solution 235-10, and the 602-10- ^ gas in carbon dioxide are agitated with mixer 235-10 to ensure good contact of all species. A reaction occurs in which the calcium in stream 235-10 reacts with carbon dioxide in stream 602-10 and precipitates as calcium carbonate allowing the amine to form an amine / acid complex.

CaA2 + CO2 + 2 R3N + - CaCO3 + 2 R3NHA To ensure that little volatile tertiary amine, of low molecular weight, comes out of contactor 600-10, the contact trays can be placed above the mixer. The gas jet leaves stream 610-10. In a slight modification of said scheme, in stream 235-10 may contain a significant amount (-5%) of amine if it was not separated in the amine dehydration system (e.g., 230 in Figure 1). In this case, the amine-laden supply can be added to a lower tray. To prevent the amine from leaving stream 610-10, a small side stream can be pushed from stream 235-10, it can be separated from the amine, and the resultant amine free bottoms can be added to the top tray of the amine. contactor 600-10. The precipitate of calcium carbonate is removed in the solids separator 620-10 (for example, filter, cyclone or centrifugation). Through the use . . - - ^, ^ of solids separator 625-10, the wash water 637-10 removes the amine / residual acid complex. The solids separator 620-10 and 625-10 can be the same piece of equipment; for better understanding, the filtration modes and wash operation modes shown in figure 10 use different pieces of equipment. The washed calcium carbonate 626-10 can be sent to the fermenter 220 or the lime kiln 260 (see Figure 1) with the proviso that the amine content is sufficiently low. If necessary, the volatile amine can be removed from the calcium carbonate using the 680-10 dryer. The 685-10 engine spins the 690-10 propeller to ensure good contact between superheated steam and solids. The outgoing steam is sent to the amine dehydration system (eg, 230 in Figure 1) to provide the energy for the water to be separated from the amine. If the reaction is carried out with a large amount of water, the water can be removed from stream 620-10 using the multi-effect evaporator 630-10. Three effects are shown in Figure 10, but less or more may be used depending on the economic aspects. Any amine in streams 630-10 and 634-10 can be removed from the water by separation. Alternatively, to promote energy efficiency, currents 633-10 and 634-10 can be returned to the amine dehydration system, provided that the same amine is used in both systems. The vapors leaving the multi-effect evaporator 634-10 can be used to supply the latent heat necessary to separate the water and amine phase in the amine dehydration system.

»G g The liquid stream 632-10 leaving the multi-effect evaporator 630-10 contains a tertiary amine complex with low molecular weight / acid and small amounts of water. In the distillation column 635-10, the low molecular weight amine R3N is replaced with a heavy amine high molecular R'3N R3NHA + R'3N - R'3NHA + R3N Suitable high molecular weight amines include alkanes (for example, tributylamine, trioctylamine) and triethanolamine. Although the triethanolamine itself does not have a high molecular weight, it reacts with the organic acids to make the esters that do not have very high molecular weights. Triethanolamine is preferred because it is inexpensive and is widely used in the processing of natural gas. The distillation column 635-10 is also operated below the temperature at which the amine / acid complex decomposes (triethylamine acetate decomposes from 140 ° C to 160 ° C). The sumptuous steam (or an inert gas is added to the bottom of the column to promote good mass transfer in the trays.) By ejecting a stream liquid side of the tray in the column (not shown in Figure 10), and the heat supply using a heat exchange, the water and tertiary amine of low molecular weight is evaporated leaving the weight tertiary amine complex high molecular / acid mainly in the liquid phase. A condenser Partial 638-10 allows reflux to be added to the distillation column to ensure that little high molecular weight amine leaves the top. To promote energy efficiency, the vapors 700 of the partial condenser can be directed to the amine dehydration system (eg, 230 in Figure 1). The lower portions 641-10 of the distillation column 635-10 contain a high molecular weight / acid tertiary amine complex. These are preheated in a 640-10 countercurrent heat exchanger and introduced into the reactive distillation column 645-10. Said column is operated above the decomposition temperature of the amine / acid (approximately 170 ° C) where the following reaction occurs R '3NHA - R' 3N + HA The volatile acid 705 leaves the top of the column. The 639-10 condenser allows reflux to be added to the distillation column to ensure that little amine leaves the top. To promote energy efficiency, the latent heat of the condenser 639-10 can be expelled to the amine dehydration system (eg, 230 in Figure 1). The high molecular weight tertiary amine 643-10 leaving the bottom of the reactive distillation column 645-10 is cooled in a 640-10 countercurrent heat exchanger and sent to the 635-10 distillation to intercarate with the low molecular weight tertiary amine. A small stream 710 is removed from the lower parts of the distillation column 645-10 to recover the precipitated minerals that accumulate. The solids separator 715 (eg filter, hydroclone, centrifugation) removes the solids from the high molecular weight tertiary amine. Said solids are sent to the solids separator 720 where they are washed with low molecular weight tertiary amine 725. The solids separator 715 and 720 can be the same piece of equipment; for better understanding, the filtration modes and wash operation modes shown in figure 10 use different pieces of equipment. The liquid stream that pulls from the solids separator 720 is a mixture of high molecular weight tertiary amine and low molecular weight tertiary amine. Said stream is preheated using current exchanger 730 and sent to distillation column 735, which separates the two amines. The partial condenser 740 condenses a part of the low molecular weight tertiary amine and refluxes back to the distillation column to prevent the high molecular weight tertiary amine from leaving the upper parts. The vapors leaving the distillation column 735 are sent to the amine dehydration system (eg, 230 in Figure 1) to provide the energy to separate the water from the amine. The washed solids 770 are directed to the dryer 745, where they are contacted with the superheated steam separating the tertiary amine of low molecular weight. To ensure good contact of the solids with the superheated steam, the contents are agitated using the 755 propellant controlled by the 750 motor. The dry minerals 760 leave the dryer 745. If necessary, a small amount of acid can be secured (for example, example, sulfuric acid) to ensure that all salt cations (eg, K +) have an anion attached (eg, SO42"). Yet another modality is shown in Figure 11 (RD recovery method) which also allows Low-boiling acids (eg, acetic acid) are "released" from the calcium salts of acids In this method, the calcium salts of the acid are contacted directly with the tertiary amine of high molecular weight, unlike the previous method, which uses low molecular weight tertiary amine The acid salt solution 235-11 of the amine dehydration section, (for example, 230 in Figure 1) is about 20% acid salt with the remaining water. A lower water content is possible if the acid salt solution is further dehydrated using multi-effect evaporators. The acid salt solution 235-10 flows into contactor 602-11, which contacts the acid salt solution with the carbon dioxide rich stream 602-11 and a high molecular weight tertiary amine 643-11. Suitable high molecular weight amines include higher alkanes (e.g. tributylamine, trioctylamine) and triethanolamine. Although the triethanolamine itself does not have a high molecular weight, it reacts with the organic acids to make the esters do not have high molecular weights. Triethanolamine is preferred because it is inexpensive and is widely used in the processing of natural gas. The tertiary amine of high molecular weight 643-11, acid salt solution 235-11, and 602-11 gas rich in carbon dioxide are agitated with mixer 605-11 to ensure good contact of all species. A reaction occurs in which the calcium in stream 235-11 reacts with the carbon dioxide in stream 602-11 and precipitates as calcium carbonate, allowing the amine to form an amine / acid complex. CaA2 + CO2 + 2 R'3N + H2O - CaCO3 + 2 R'3NHA To ensure that none of the high molecular weight tertiary amides exit the 600-11 contactor, the contact trays can be place above the mixer. The jet of gases exits in stream 610-11. The calcium carbonate precipitate is removed in the solids separator 620-11 (for example, filter, cyclone, or centrifuge). By using the solids separator 625-11, the low molecular weight tertiary amine 800 of the amine dehydration system (eg, 230 in Figure 1) removes the residual amine / acid complex. The solids separators 620-11 and 625-11 can be the same piece of equipment; for better understanding, the filtration modes and washing operation modes shown in figure 11 use different pieces of equipment. The washed calcium carbonate 626-11 must have a volatile low molecular weight tertiary amine removed from carbonate of calcium using the 680-11 dryer. Engine 685-11 rotates thruster 690-11 to ensure good contact between superheated steam and solids. The outgoing steam is sent to the amine dehydration system (eg, 230 in Figure 1) to provide energy for the water to be separated from the amine.

If the previous reaction is carried with a large amount of water, the water can be removed from stream 629-11 using a 630-11 multi-effect evaporator. Three effects are shown in Figure 11, but less or more effects can be used depending on the economic aspects. To promote energy efficiency, currents 633-11 and 634-11 can be returned to the amine dehydration system. The vapors 634-11 leaving the multi-effect evaporator can be used to provide the latent heat necessary to separate the water and amine phase in the amine dehydration system. The liquid stream 632-11 leaving the multi-effect evaporator 630-11 contains a high molecular weight acid / tertiary amine complex and small amounts of water. The distillation water is removed in the distillation column 635-11. The distillation column 635-11 is operated below the temperature at which the amine / acid compound decomposes. Superheated steam (or an inert gas) is added to the bottom of the column to promote good mass transfer in the trays. By ejecting a side stream of liquid from the trays in the column (not shown in Figure 11), and providing heat using a heat exchanger, the water will evaporate leaving the high molecular weight / acid tertiary amine complex mainly in the liquid phase. The partial condenser 638-11 allows to reflux the water to be added to the distillation column to ensure that little amine leaves the top. To promote the efficiency of the energy, the vapors 700-11 of the partial condenser They can be directed towards the system of amine dehydration (eg, 230 in Figure 1). Distillation column 635-11 can be removed if water can not be tolerated in the downstream process steps. Lower portions 640-11 of distillation column 635-11 contain high molecular weight / acid tertiary amine complex. These are preheated in the countercurrent heat exchanger 640-11 and introduced to the reactive distillation column 645-11. Said column is operated above the decomposition temperature of the amine / acid (approximately 170 ° C) where the next reaction occurs.

R'3NHA - R'3N + HA The volatile acid 705-11 leaves the top of the column. The 639-11 condenser allows reflux to be added to the distillation column to ensure that little amine leaves the top. To promote energy efficiency, the latent heat of the condenser 639-11 can be expelled to the amine dehydration system (eg, 230 in Figure 1). The high molecular weight tertiary amine 643-11 leaving the bottom of the reactive distillation column 645-11 is cooled in a countercurrent heat exchanger 640-11 and sent to the 600-11 contactor to react with the salt of calcium of acid.

A small stream 710-11 is removed from the lower parts of the reactive distillation column 645-11 to recover the precipitated minerals that accumulate. The solid separator 715-11 (eg, filter, hydroclone, centrifugation) removes the solids from the high molecular weight tertiary amine. Said solids are sent to the solids separator 720-11 where they are washed with low molecular weight tertiary amine 725-11. The solids separator 715-11 and 720-11 can be the same piece of equipment; for better understanding, the filtration modes and washing operation modes shown in figure 11 use different pieces of equipment. The liquid stream 765-11 exiting the solids separator 720-11 is a mixture of high molecular weight tertiary amine and low molecular weight tertiary amine. Said stream is preheated using a countercurrent heat exchanger to 730-11 and sent to the distillation column 735 which separates the two amines. The partial condenser 740-11 condenses part of the low molecular weight tertiary amine and refluxes it back to the distillation column to remove the high molecular weight tertiary amine from the topsides. The vapors leaving the distillation column 735-11 are sent to the amine dehydration system (eg, 230 in Figure 11) to provide energy to separate the water from the amine. The washed solids 770-11 are directed towards the dryer 745-11, where they are brought into contact with the superheated steam separating the tertiary amine of low molecular weight. To ensure good contact of the solids with the superheated steam, the contents are agitated using the 755- # 11 engine driven engine 75 € £ The dry minerals 760-11 come out of the 745-11 dryer. If necessary, a small amount of acid (eg, sulfuric acid) can be added to ensure that all salt cations (eg, K +) have an anion attached (eg GÉ, SO 2"). Still another alternative mode is shown in Figure 12 (recovery method RE), which allows low-boiling acids (eg acetic acid) to be "released" from the calcium salts of the acids. RC recovery, except that the low molecular weight tertiary amine is replaced by ammonia.The advantage is that the ammonia is economical, so that losses can be tolerated, in the same way, because the ammonia can be added to the fermenter as A source of nitrogen, any loss of ammonia that is directed to the fermenter (for example, 220 in Figure 1) has no cost, because the ammonia can be added to the fermenter in any form. 5-12 of the amine dehydration section (eg, 230 in Figure 1) is about 20% acidic salt with substantially all the remaining water. A lower water content is possible if the acid salt solution is further dehydrated using multi-effect evaporators. This flows in contactor 600-12, which puts in contact the solution of acid salt with current rich in carbon dioxide 602-12 and ammonia 900. Ammonia 900, acid salt solution 235-12, and rich gas in 602-12 carbon dioxide are agitated with the 605-12 mixer to ensure good contact of all species. A reaction occurs in which the calcium in stream 235-12 reacts with the carbon dioxide in stream 602-12 and precipitates as calcium carbonate allowing the ammonia to form an ammonia / acid complex.

CaA2 + CO2 + 2 NH3 + H2O - CaCO3 + 2 NH4A To ensure that little of the volatile ammonia exits the 600-12 contactor, the contact trays can be placed above the mixer. The jet of gases comes out in stream 610-12. The precipitate of calcium carbonate is removed in the solid separator 620-12 (eg, filter, cyclone, or centrifugation). By using the solids separator 625-12, the wash water 637-12 removes the ammonia / residual acid complex. Solids separators 620-12 and 625-12 can be the same piece of equipment; for better understanding, the filtration modes and washing operation modes shown in figure 12 use different pieces of equipment. The washed calcium carbonate 626-12 can be sent directly to the fermenter (for example, 220 in Figure 1) because there is no penalty associated with the ammonia returning to the fermenter. For calcium carbonate 626-12 that is being sent to the lime kiln (for example, 260 in Figure 1) it is necessary to remove the residual ammonia using dryer 680-12. The 685-12 engine spins the 690-12 propeller to ensure good contact between superheated steam and solids. The outgoing steam condenses in the condenser 905. To promote the efficiency of the energy, the Heat is expelled to the amine dehydration system (eg, 230 in Figure 1) to provide the latent heat necessary to cause phase separation between the amine and water. If the above reaction is carried out with a large amount of water, the water can be removed in stream 629-12 using multi-effect evaporator 630-12. Three effects are shown in Figure 12, but less or more effects may be cooled depending on the economic aspects. Any ammonia in streams 633-12 and 634-12 can be removed from the water by separation. Alternatively, to promote energy efficiency, currents 633-12 and 634-12 can be returned to the amine dehydration system (for example 230 in Figure 1). The vapors leaving the multi-effect evaporator 634-12 can be used to provide the latent heat necessary to phase-separate the water and the amine in the amine dehydration system (eg, 230 in Figure 1). The liquid stream 632-12 leaving the multi-effect evaporator 630-12 contains ammonia / acid complex and small amounts of water. In distillation column 635-12, the ammonia is replaced with a high molecular weight amine NH4A + R ^ N-R'sNHA + NH3 Suitable high molecular weight amines include higher alkanes (e.g. tributylamine, trioctylamine) and triethanolamine. Although triethanolamine i «Mr- **** -" ^ itself does not have a molecular weight -a ®, reacts with organic acids to make the esters do not have very high molecular weights.Triethanolamine is preferred because it is economical and is used The 635-12 distillation column is operated below the temperature at which the ammonia / acid complex decomposes, because the ammonia is not a tertiary amine, it can be formed potential amides, thus, if necessary, the distillation column 635-12 can be operated under vacuum to keep the temperature as low as possible to avoid amide formation.Superheated steam (or an inert gas) is added to the lower part of the column to promote good mass transfer in the trays by expressing a lateral stream of the liquid from the trays in the column (not shown in figure 12), and by supplying heat using or a heat exchanger, water and ammonia will evaporate leaving the high molecular weight / acid tertiary amine complex mainly in the liquid phase. The condenser 638-12 is also refluxed to be added to the distillation column to ensure that the high molecular weight amine leaves the top. To promote energy efficiency, the heat of the condenser 638-12 can be directed to the amine dehydration system (eg, 230 in Figure 1). The lower portions 641-12 of the distillation column 635-12 contain a high molecular weight / acid tertiary amine complex. This is preheated in a 640-12 countercurrent heat exchanger and introduced jjj ^ gEg ^ to the reactive distillation column 645-12. Said column is operated above the decomposition temperature of the amine / acid (approximately 170 ° C) where the next reaction occurs. * X R'3NHA R'3N + HA The volatile acid 705-12 leaves the top of the column. Condenser 639-12 allows reflux to be added to the distillation column to ensure that little amine leaves the top. To promote energy efficiency, the latent heat of the condenser 639-12 can be expelled to the amine dehydration system (eg, 230 in Figure 1). The high molecular weight tertiary amine 643-12 leaving the bottom of the distillation column of active 641-12 is cooled in a countercurrent heat exchanger 640-12 and sent to the distillation column 635-12 for interchange with ammonia. A small stream 710-12 is removed from the lower parts of the reactive distillation column 645-12 to recover the precipitated minerals that accumulate. The solids separator 715-12 (for example, filter, hydroclone, centrifugation) removes the solids from the high molecular weight tertiary amine. Said solids are sent to the solids separator 720-12 where they are washed with low molecular weight tertiary amine 725-12. The solids separator 715-12 and 720-12 can be the same piece of equipment; for better understanding, the filtration modes and washing operation modes shown in figure 12 zeXyy jgra jg »Sj ^^^ i use different pieces of equipment. The liquid stream 765-12 leaving the solid separator 720-12 is a mixture of high molecular weight tertiary amine and low molecular weight tertiary amine. Said stream is precalled using a countercurrent heat exchanger 730-12 and sent to the distillation column 735-12, which separates the two amines. The partial condenser 740-12 condenses a part of the low molecular weight tertiary amine and refluxes it again making the distillation column to remove the high molecular weight tertiary amine from the upper parts. The vapors leaving the distillation column 735-12 are sent to the amine dehydration system (eg, 230 in Figure 1) to provide energy to separate the water from the amine. Typically, the low molecular weight amine will be the same as that used in the amine dehydration system (eg, 230 in Figure 1). The washed solids 770-12 are directed to the dryer 745-12 where they are contacted with the superheated steam that separates the tertiary amine of low molecular weight from residual weight. To ensure good contact of the solids with the superheated steam, the contents are agitated using the 755-12 propellant controlled by the 750-12 engine. Dry minerals 760-12 leave dryer 745-12. If necessary, a small amount of acid (eg sulfuric acid) can be added to ensure that all salt cations (eg, K +) have an anion attached (eg SO42"). All recovery methods RA a RE are described herein in terms of a single product (eg, acetic acid, acetone). mg ^ ^ 8ggg Since deimfeptation liquids rarely contain an X component? Once dissolved, it will be necessary to distill the recovered products if a pure product is desired. The foregoing may or may not be necessary. For example, if the ketone products of the recovery method R-A are to be hydrogenated with alcohols to be mixed in the motor fuel, the mixed ketone products are sufficient. However, if chemical grade acetone is sold, it will have to be separated from the higher ketones (eg, methyl ethyl ketone, diethyl ketone) using distillation or other suitable technologies. A preferred mode for the methods presented herein utilizes a low molecular weight amine to remove water from the fermentation liquid in the amine dehydration system (eg, 230 in Figure 1). The advantages of this method, compared with others, have already been described. The recovery methods R-A to R-E are integrated with the concentration section of said plant because the heat and waste vapors containing the low molecular weight tertiary amine are returned to the amine dehydration system. All the procedures described in this way neutralize the acids in the fermenter with lime or calcium carbonate. If the acids are neutralized with ammonia, then ammonium acetate (propionate, butyrate, lactate) can be produced in the concentration section of the plant instead of calcium acetate (propionate, butyrate, lactate). However, the amine dehydration system more selectively concentrates the divalent units (eg, calcium) than the monovalent ions (eg, sodium, ammonium). '^^ ¡^^^ ¡^^ wßSßMg ^^^^ yyg ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^ However, if the ammonium is the cation, the RE recovery method can be used (without the lime kiln 260 (figure 1), 600-12 contactor, and calcium carbonate filter 620-12 ).

EXAMPLES In order to facilitate a more complete understanding of the invention, several specific examples are given below. However, the scope of the invention is not limited to the specific embodiments described in said examples, which are for purposes of illustration only.

EXAMPLE 1 Conversion of biomass to organic acids Fermentation F-A Biomass (eg, clapper, grass, municipal solid waste) is placed in a tank. The hot water is added from a recycle stream. If desired, the heated gases (CO2, N2 and O2) in a stream in the recycle can be bubbled through the water to heat it later. Lime is added to the biomass. The lime / water / biomass suspension is rinsed for 1 to 24 hours while stirring. When the rinsing is finished, the lime water is drained from the solid suspension. It can remove additional lime by leaching the biomass with recycled water. The biomass treated with lime is added slowly to a fermentor, where the anaerobic organisms convert the biomass into organic acids. These organisms are a mixed crop that is obtained from several sources (for example, livestock rumen, anaerobic sewage releases). They produce a variety of products, mainly acetic acid with minor amounts of propionic and butyl acids. The ratio of these products depends on the factors, such as the microbial population, pH, and temperature. Acetic acid dominates at temperatures above 55 ° C. As organic acids are formed, the pH is reduced. The lime that was not recovered during the leaching process will act to neutralize the acids through the formation of calcium salts. The pH is further regulated by the addition of water with lime from the leaching. Alternatively, recycled calcium carbonate can be used. Generally, an approximate pH of 6.2 is preferred, but pH ranging from about 5.5 to 7.0 is adequate. Because there are no asepsis requirements (that is, supplies and containers should not be sterilized), recycling can be used without risk of contamination. The fermenters will operate in a continuous manner. The cells can be recycled to maintain a high concentration of cells in the fermenters that will reduce the residence time required. The concentration of solids in the fermenter will be high (around 10-25%) to make the most efficient use of the fermenter volume. If all the When the carbohydrates in the biomass are converted to organic acids, the concentration of organic acid will be around 8-20%, which is much higher than what can be tolerated by microbes. To avoid such a problem, the liquid is constantly removed from the fermenters to maintain the organic acid salt concentration below about 3.4%. Several methods can be used to separate the solids from the liquid (for example, filters, decanters). For example, the suspension can be pumped through a hydroclone in which the centrifugal force of the stirred fluid separates the solids from the liquid. The liquid will still have some particles because the separation is not perfect; therefore, it can be further clarified by filtration through a sand filter, or similar device. When the sand filter is backflushed, the solids are simply returned to the fermenters for further conversion to organic acids. The biomass will travel through the fermentor train essentially in a piston type expense. The carbohydrate content of the biomass will be reduced as it is converted to organic acids. In the long run, the solids will consist mainly of lignin, calcium carbonate and cells. The cells can be recovered separately because they settle more slowly than the uningested solids and calcium carbonate. The remaining solids (lignin and calcium carbonate) can be burned in a lime kiln to provide the heat process and convert the calcium carbonate to lime.

MÉ ^^ - a _- ^ iihM ^^^ MÉ _ ^^ ttütt? M ^ _ ^. ^ Mtfttl EJgllPLO2 Conversion of biomass to organic acids Fermentation F-B This fermentation is similar to fermentation A, except that acetic acid and ethanol are produced simultaneously by thermophilic bacteria. The cellulitic organism Clostridium thermocellum is used. This has a high cellulase activity that can convert hexoses to ethanol and acetic acid in approximately equal amounts. Because this organism is incapable of using pentose sugars, Clostridium thermosaccharolyticum, C. Thermohydrosulfuricum, or Thermoanaerobacter ethanolicus can be co-cultivated with C. Thermocellum. The ethanol is recovered by distillation, while the acetic acid is concentrated and recovered by the methods described below. If organisms are more tolerant to acetate ions than ethanol, much of the lower parts of the distillation column can be recycled to the fermenter, allowing acids to accumulate higher concentrations. Said procedure requires asepsis, because a pure culture (or coculture) is being maintained. The treatment by lime may be sufficient to sterilize the biomass and water. However, if contamination is a problem, it will be necessary to sterilize the biomass by direct steam injection. The water can be sterilized using conventional sterilization equipment (for example, countercurrent heat exchangers with a high temperature maintenance section). The fermenter can be operated in a batch and in continuous mode, however, the batch mode is prone to have fewer contamination problems. All the procedures described neutralize the acids in the fermenter with lime. If the acids are neutralized with ammonia, then ammonium acetate (propionate, butyrate, lactate) can be produced in the plant concentration section of the calcium acetate site (propionate, butyrate, lactate).

EXAMPLE 3 Concentration by extraction with low molecular weight amines The fermentation liquid of fermentation F-A or fermentation F-B contains about 3-4% of organic acid salts, therefore there are about 25 to 33 parts of water per part of organic acid. Said water must be removed to coat the product that can be reached by extracting the water from the fermentation liquid. Secondary and tertiary amines of low molecular weight (low MW) with about 5 to 6 carbon atoms per molecule are preferred. There are several candidate amines (as Davison et al. Are described), the preferred amines are diisopropyl, triethyl, and methyldiethyl. The mixtures of triethyl and methyldiethyl amine are very useful, because the operating temperature of the extractor can be regulated by exchanging the triethyl: methyldiethyl ratio.

Through the use of lime, the fermentation liquid is adjusted to a pH of about 11 to prevent the low-MW amines from reacting with acids in the fermentation liquid. Said alkaline liquid is contacted by countercurrent with the PM-low amine. Because there is heat from the mixture, cooling is necessary to maintain the desired temperature. If the extraction is carried out at a low temperature (for example, 40 ° C) the heat of the mixture must be expelled into the cooling water. However, if the extraction is carried out at a high temperature (eg, 60 ° C), then said heat may be useful as well as the heat of the very low grade process in the final stage of a multi-effect evaporator. . The extraction temperature will essentially be the same as the temperature of the fermenter to eliminate heating (or cooling) of fermentation liquid prior to its entrance to the extractor. A preliminary engineering study indicates that a 5-stage extractor will remove 86% of the water, producing a stream of aqueous product with 20% salt concentration. The PM-low amine stream with the extracted water is then heated to about 20 ° C higher than the extractor temperature. The above causes the water to separate from the amine because they have little miscibility at higher temperatures. Much of the temperature rise to 20 ° C is achieved by the current contact of the incoming amine / water solution with the outgoing amine. The rest of the temperature rise is achieved by the direct injection of steam (which contains some amines of PM-low) into the incoming solution. The water / amine separation is not perfect, because the aqueous phase contains about 5% (w / w) of amine, and the amine phase contains about 5% (w / w) of water. The amine phase is simply recycled in the extractor while the aqueous phase must be separated from the amine. The separator can be operated at a high pressure, so that the outgoing vapors can be used for processing heat. Many of these vapors will be injected directly into the amine separator to complete the necessary temperature rise of 20 ° C. The efficiency of the separation is greatly improved by adjusting the pH to around 11 using lime. The aqueous phase leaving the extractor can be further concentrated in a multi-effect evaporator. A part of the value required by the evaporators can be supplied from the vanishing column vapors.

EXAMPLE 4 Conversion of biomass to liquid fuel Said recovery method produces ketones (e.g., acetone, methyl, ethyl, ketone, diethyl ketone, etc.) of the organic acid salts (e.g., acetate, propionate, butyrate). Although many of the organic acid salts are present in the mixtures, the process that affects calcium acetate will be described in this illustrative example. Calcium acetate can be converted almost stoichiometrically to acetone and calcium carbonate by pyrolyzing at 400-450 ° C. It is important to remove the acetone as soon as it forms, because it will decompose at such high temperatures.

An aqueous stream containing 20% calcium salts of organic acids is produced as described in Example 3. The multi-effect evaporators can be used in the concentration section to remove much of the water that precipitates calcium acetate. The solids are removed by filtration and the liquid is returned to the multi-effect evaporators. The solids are dried by blowing hot gases from the lime kiln through a dryer, that is, a horizontal tank with an internal mixer that allows good contact between solids and hot gases. Alternatively, solids can be dried using superheated steam. The dried calcium acetate is transported to the pyrolizing closure hopper using a screw conveyor. When the closing hopper opens, the calcium acetate enters the thermal converter where it is mixed with a heat transfer medium (for example, glass beds). Calcium acetate reacts to form calcium carbonate and acetone. The acetone is cooled by its contact with the incoming calcium acetate, then condenses and recovers. The acetone vapor pressure is low if the acetone is condensed at low temperatures, thus allowing the thermal converter to operate under vacuum. The above ensures that the acetone has a short residence time in the thermal converter. The required residence time of the solids is around 10 minutes (depending on the temperature) for a complete reaction. Because some non-condensable materials can enter the * _ ^ M ^^ _ thermal converter, a small and empty pump may be necessary to remove them. The calcium carbonate leaving in the thermal converter is separated from the heat transfer medium. The calcium carbonate can be sent to a lime kiln to regenerate the lime or it can be added directly to the fermenter as a neutralizing agent. The heat transfer agent is heated by direct contact with hot gases, such as those leaving the kiln for lime or a combustor. Because the biomass contains minerals (up to about 10% for some grasslands and herbaceous crops), these minerals must be purged. The soluble minerals can be removed by dragging a side stream from the calcium carbonate and by washing with water. The insoluble minerals can be recovered from the stream leaving the kiln for lime by dissolving the lime in water and recovering the insoluble minerals. Calcium phosphate will be an important component of insoluble minerals. In this way it can be acidified by the addition of sulfuric acid, which will cause the gypsum (calcium sulphate) to precipitate allowing the phosphorus to recover as phosphoric acid. The minerals recovered from these lateral streams can be sold as fertilizers, so that part of the plant is expected to recover with fertilizer sales. The gases that come out of the kiln for lime are very hot (around 900 ° C). These gases provide the thermal energy process. High pressure steam can be made from the most customer gases and used to produce electricity. Lower temperature gases (around 550 ° C) will heat the heat transfer medium. Subsequently, a part of the low pressure steam can be made to provide energy for the multi-effect evaporators. Finally, the lower temperature gases can be used to dry the VFA salts, the water heated in the biomass flushes the container or provides heat to the amine dehydration process. Recovery methods are exemplified by a single product (eg, acetic acid, acetone). However, fermentation liquids rarely contain a single dissolved component. Therefore, it will be necessary to further distill the recovered products if a pure product is desired. The foregoing may or may not be necessary. For example, if the acetone products are hydrogenated with alcohols that are mixed in the motor fuel, the mixed acetone products are sufficient. However, if chemical grade acetone is sold, it will have to be separated from higher ketones (eg, methyl ethyl ketone, diethyl ketone) using distillation or other suitable technologies. For purposes of clarity of understanding, the above invention has been described in detail by way of illustration, and for example, together with specific embodiments, although other aspects, advantages, and modifications will be apparent to those skilled in the art to which it belongs. . The description and examples above are intended to illustrate, but not limit the scope of the invention. Modifications of the modes described above for carrying out the invention, which are apparent to the experts in biochemistry, fermentation engineering chemistry and / or related fields, are intended to be within the scope of the invention, which is limited only by the appended claims. All publications and patent applications mentioned in this specification are indicative of the level of experience of those skilled in the art, to which this invention pertains. All publications and patent applications herein are incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. , and r. . ^,., ^ j- B. ^. ^.

Claims (29)

NOVELTY OF THE INVENTION CLAIMS

1. A process for recovering the low-boiling acids from a concentrated solution of calcium salts of the acids comprising: contacting a concentrated solution of calcium salt of low-boiling acids with a tertiary amine of molecular weight low and carbon dioxide; forming calcium carbonate precipitate and a liquid solution containing a low molecular weight / acid tertiary amine complex; washing the calcium carbonate precipitate with water to remove the residual low molecular weight tertiary amine; replacing the low molecular weight / acid tertiary amine complex with a high molecular weight tertiary amine by an exchange reaction; and thermally breaking the high molecular weight / acid tertiary amine complex and allowing the high molecular weight tertiary amine to be separated from the low volatile boiling acid.

2. The process according to claim 1, further characterized in that the low molecular weight tertiary amine is also used in the dehydration step of amine used to produce the concentrated solution of calcium salt of low boiling acids.

3. The process according to claim 1, further characterized in that the high molecular weight / acid tertiary amine complex is thermally broken in a reactive distillation column. & É | ^^^^ B fa¿ ^^^^ fjM || iBUMfaÉ1

4. - The process according to claim 1, further characterized in that the water is removed using evaporation or multi-effect distillation, or both, prior to thermal breakage of the high molecular weight / acid tertiary amine complex.

5. The process according to claim 1, further characterized in that the salt precipitate is separated from the high molecular weight tertiary amine, washed with a volatile solvent, and the salt precipitate is dried to remove the volatile solvent, the recovered washing fluid is separated by distillation.

6. The process according to claim 5, further characterized in that the volatile solvent is a tertiary amine of low molecular weight.

7. The process according to claim 6, further characterized in that the low molecular weight tertiary amine is used in the amine dehydration system.

8. The process according to claim 1, further characterized in that the precipitate of washed calcium carbonate is further dried to remove the residual volatile low molecular weight tertiary amine.

9. A process for recovering low boiling acids from a concentrated calcium salt solution of the acid comprising: contacting a concentrated solution of calcium salt of low boiling acids with a weight tertiary amine low molecular EKOb and carbon dioxide, form the precipitate of calcium carbonate and a liquid solution containing a tertiary amine complex of high molecular weight / acid, wash the precipitate of calcium carbonate with a volatile solvent to remove the tertiary amine of molecular weight high residual, dry the calcium carbonate precipitate 5 to remove the residual volatile solvent, and thermally break the high molecular weight / acid tertiary amine complex and allow the non-volatile high molecular weight tertiary amine to be separated from the high molecular weight amine acids. low boiling point volatiles.

10. The process according to claim 9, further characterized in that the volatile solvent is a low molecular weight amine.

11. The process according to claim 10, further characterized in that the low molecular weight amine is used in an amine dehydration step to produce the concentrated solution of calcium salt of low boiling acids.

12. The process according to claim 9, further characterized in that the high molecular weight / acid amine complex is thermally broken in a reactive distillation column.

13. The process according to claim 9, further characterized in that the water is removed using evaporation or multi-effect distillation, or both, prior to thermal breakdown in the high molecular weight / acid amine complex. g "¡t, tÉÉ ^^ to_k ^^ aM ^^ iMiteaMl _ ^^^^^^ MHriiM [Ui ^^ HÍ! íÍMÍTIILK ^^ __ ^^^^^ Í

14. The process according to claim 9, further characterized in that the salt precipitate is separated from the high molecular weight tertiary amine, washed with a volatile solvent, and dried to remove the volatile low molecular weight amine, the recovered wash fluid it is separated by distillation.

15. The process according to claim 14, further characterized in that the volatile solvent is a low molecular weight amine.

16. The process according to claim 14, further characterized in that the volatile solvent is the same low molecular weight amine used in the amine dehydration system to produce the concentrated salt solution.

17. A process for recovering low-boiling acids from a concentrated solution of calcium salt of the acid comprising: contacting a concentrated solution of calcium salt of low-boiling acids with ammonia and carbon dioxide; forming the precipitate of calcium carbonate and a liquid solution containing an ammonia / acid complex; replacing the ammonia in the ammonia / acid complex with a high molecular weight tertiary amine by an exchange reaction; separating the ammonia from the high molecular weight tertiary amine, and thermally breaking the high molecular weight / acid tertiary amine complex and allowing the high molecular weight tertiary amine to be separated from the low volatile boiling acid.

18. - The process according to claim 17, further characterized in that the high molecular weight / acid tertiary amine complex is thermally broken in a reactive distillation column.

19. The process according to claim 17, further characterized in that the water is removed using evaporation or multi-effect distillation, or both, prior to thermal breakage of the high molecular weight / acid tertiary amine complex.

20. The process according to claim 17, further characterized in that the salt precipitate is separated from the tertiary amine of high molecular weight, washed with a volatile solvent, and dried to remove the volatile solvent, the recovered washing fluid is Separate by distillation.

21. The process according to claim 20, further characterized in that the volatile solvent is a tertiary amine of low molecular weight.

22. The process according to claim 21, further characterized in that the low molecular weight tertiary amine is also used in an amine dehydration system to produce the concentrated salt solution.

23. The process according to claim 17, further characterized in that the washed calcium carbonate precipitate is further dried to remove residual volatile ammonia.

24.- A procedure to remove high-boiling acids from a concentrated solution of the acid that comprises: put in |, contact a concentrated calcium salt solution of a high boiling acid with a low molecular weight tertiary amine and carbon dioxide; forming the calcium carbonate precipitate and a liquid solution containing a low molecular weight / acid tertiary amine complex; washing the calcium carbonate precipitate with water to remove the low molecular weight tertiary amine, and thermally breaking the low molecular weight tertiary amine / acid complex to remove the volatile low molecular weight tertiary amine from the high boiling acid liquid.

25. The process according to claim 24, further characterized in that the tertiary amine of low molecular weight is also used in an amine dehydration step to produce the concentrated solution of calcium salt or a high boiling acid. .

26. The method according to claim 24, further characterized in that the low molecular weight / acid tertiary amine complex is thermally broken in a reactive distillation column.

27. The process according to claim 24, further characterized in that the water is removed using evaporation and / or multiple effect distillation prior to thermal breakage of the low molecular weight / acid tertiary amine complex.

28. The process according to claim 24, further characterized in that the salts are removed from the high-boiling acid by evaporation of multiple effects using an acid strong enough to provide anions for the metal cations.

29. The process according to claim 24, further characterized in that the washed calcium carbonate precipitate is dried to remove the residual volatile low molecular weight tertiary amine.