BRPI1010343A2 - integrated biodiesel production process - Google Patents

Abstract

PROCESS OF INTEGRATED BIODIESEL PRODUCTION. Integrated processes for the production of biodiesel based on fatty acid alkyl ester and the production of tri-isoalkyl glycerols are revealed.

Description

INTEGRATED BIODIESEL PRODUCTION PROCESS

BACKGROUND OF THE INVENTION

Field of the Invention

Modalities disclosed herein generally relate to biodiesel production. In one aspect, embodiments disclosed herein relate to processes for the production of fatty acid alkyl ester-based biodiesel and the production of tri-isoalkyl glycerols. In other aspects, embodiments disclosed herein relate to processes for the production of fatty acid methyl ester (FAME) -based biodiesel and the production of triisobutyl glycerols.

Bedding

Diesel fuel is a fractionated petroleum distillate that is used as fuel in diesel engines. Diesel engines power most trains, large trucks and ships in the world. The raw materials for diesel, petroleum is a fossil fuel and therefore a non-renewable resource of finite source. In addition, diesel engines produce greenhouse gas emissions fifteen percent more per liter than gasoline. Acute shortages and resulting dramatic oil price increases in refined petroleum products have fueled interest in alternative fuels. Thus, extensive research efforts are already being directed towards replacing some or all petroleum-derived diesel fuels with cleaner-burning alternative fuels such as biodiesel.

Biodiesel is produced from biomaterials rich in fats and oils, for example vegetable oils. The basic chemistry involved in biodiesel production is the catalytic exchange of natural esters, mainly glycerides, with a primary alcohol. Biodiesel is therefore a mixture of methyl or ethyl esters of various saturated and unsaturated fatty acids with a glycerol co-product.

Biodiesel is a diesel equivalent processed fuel that can be used on any diesel engine without the need for mechanical changes and is compatible with existing fuel distribution infrastructure.

A blend of 20% biodiesel with 80% petroleum (B20) can be used on all diesel firing equipment, including compression ignition engines and oil heaters, without modification. Larger blends, including pure biodiesel,

can be used on many engines made after 1994, but minor modifications may be required.

Biodiesel is biodegradable and non-toxic, and typically produces about sixty percent less greenhouse gas emissions than diesel derived from

2 0 oil. Even in mixtures as low as 20% of

biodiesel, biodiesel can substantially reduce the emission levels and exhaust toxicity of diesel engines. Biodiesel is recognized worldwide as a substitute and supplement for petroleum diesel. Per

For example, biodiesel has been designated as an alternative fuel by the US Department of Energy and the US Department of Transportation, and is registered with the United States Environmental Protection Agency as a fuel and fuel additive.

Since the introduction of biodiesel in South Africa before World War II, significant effort has been expended to increase its viability as a fuel substitute. In more recent years, environmental and economic pressures, for example, events such as oil embargoes and laws such as the Clean Air Act of 1990, which propelled the continued development of this technology.

Biodiesel can normally be produced by acid- or triglyceride-based catalyzed transesterification found in biological material. The transesterification process is a low temperature (about 65 ° C (150 ° F)), low pressure (about 1.4 bar to 2.4 bar (20 psia to 35 psia) (140 to 240 kPa)) having a high conversion reaction (eg 98%) with few side reactions and short reaction times. A secondary product of the triglyceride transesterification reaction is glycerol.

In transesterification, a fat or oil is reacted with an alcohol (such as methanol or ethanol) in the presence of a catalyst to effect the exchange of natural esters such as glyceride with the primary alcohol to produce glycerol and methyl fatty acid esters (FAME). ), the latter of which forms biodiesel. Alcohol is usually charged to excess stoichiometric to conduct the reaction and can be recovered for reuse. The catalyst may be sodium or potassium methoxide or hydroxide, which is mixed with the alcohol prior to the transesterification reaction. The resulting FAME (biodiesel) and glycerol can then be separated. Biodiesel was produced in 1973 by G. Chavanne of the University of Brussels (Belgium) by transesterification of vegetable oils with ethanol or methanol. Variations, improvements and modifications of this general process are described, for example, in U.S. Patent Application Publication No. 20040034244 and U.S. Patent Nos. 6,953,873, 4,300,009 and 4,433,184.

Glycerol ether derivatives such as triisobutyl glycerol (TIG) are also suitable components for use in biofuels. TIG may be produced, for example, by etherification of olefins, such as etherification of glycerol with isobutylene using an acid catalyst. Isobutylene is usually charged to a stoichiometric excess to drive the reaction and can be recovered for reuse. Glycerol etherification includes complex reversible equilibrium reactions. Reaction variables, such as temperature and amount of catalyst, can be used to control the concentrations of mono-, di- and triether ethers produced.

For example, U.S. Patent No. 5,476,971 discloses the reaction

20% of pure glycerol with isobutylene in the presence of a

acid catalyst in a two-phase reaction to produce tertiary butyl ethers. The etherification process is also at a low temperature (about 93 ° C (200 ° F), low pressure (about 10 bar (150 psia) (1,000 kPa)) having a high conversion reaction (eg 98% ).

Etherification of glycerol and isobutylene to produce TIG typically requires the importation of relatively pure glycerol and isobutylene. High purity feeds are generally required to avoid separation and

Return of mixed butenes and butanes. Therefore, there is a need for improved processes for the production of biodiesel fuels, including FAME and TIG.

SUMMARY OF CLAIMS OF THE CLAIMS In one aspect, embodiments disclosed herein refer to

a process for the production of a biodiesel fuel, the process including: feeding a tertiary alkyl ether to a decomposition reaction zone containing at least one decomposition catalyst; contacting the tertiary alkyl ether with at least one decomposition catalyst at a temperature and pressure to decompose the tertiary alkyl ether into an alcohol and an isoolefin; separating the alcohol and isoolefin to recover a fraction comprising the alcohol and a fraction comprising the isoolefin; feeding at least a portion of the alcohol-containing fraction and at least one of a vegetable oil and animal fat to a transesterification reaction zone, contacting the alcohol and at least one of a vegetable oil and animal fat in the presence of of at least one transesterification catalyst

20 under conditions of temperature and pressure sufficient to

transesterifying vegetable oil or animal fat to form a product comprising transesterification of alkyl esters of fatty acid and glycerol; separating the transesterification product to recover a fraction comprising the fatty acid alkyl esters and a fraction comprising the glycerol; feeding at least a part of the glycerol-comprising fraction and at least a part of the isoolefin-containing fraction to an etherification reaction zone; contact isoolefin and glycerol

30 in the presence of at least one etherification catalyst under temperature and pressure conditions to form an etherification product comprising at least one of tertiary alkyl glycerol, tertiary alkyl glycerol, and tertiary alkyl glycerol; separating the product from etherification to recover a moiety comprising tertiary alkyl glycerol and tri tertiary alkyl glycerol.

In another aspect, embodiments disclosed herein relate to a process for producing a biodiesel fuel, the process including: feeding a tertiary methyl butyl ether to a decomposition reaction zone containing at least one decomposition catalyst; contacting tertiary methyl butyl ether with at least one decomposition catalyst at a temperature and pressure to decompose tertiary methyl butyl ether in methanol and isobutylene; separating methanol and isobutylene to recover a fraction comprising methanol and a fraction comprising isobutylene; feed at least part of the fraction comprising methanol and at least

2 0 one of a vegetable oil and animal fat for an area of

transesterification reaction; contacting methanol and at least one of a vegetable oil and an animal fat in the presence of at least one transesterification catalyst under conditions of sufficient temperature and pressure to transesterify the vegetable oil or animal fat to form a product comprising transesterification of methyl esters of fatty acid and glycerol; separate the product from the transesterification to recover a fraction comprising the fatty acid methyl esters and a fraction comprising

30 comprises glycerol; feeding at least a portion of the glycerol-comprising moiety and at least a portion of the isobutylene-containing moiety to an etherification reaction zone; contacting isobutylene and glycerol in the presence of at least one etherification catalyst under temperature and pressure conditions to form an etherification product comprising at least one of tertiary butyl glycerol, tertiary butyl glycerol, and tertiary butyl glycerol ; separating the product from etherification to recover a fraction comprising tertiary butyl glycerol and tri-tertiary butyl glycerol.

Other aspects and advantages of the invention will be apparent from the following description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a simplified flowchart of a process.

for biodiesel production according to modalities disclosed herein.

DETAILED DESCRIPTION Modalities disclosed herein generally refer to biodiesel production. In one aspect, embodiments disclosed herein relate to processes for the production of fatty acid alkyl ester based biodiesel and the production of triisoalkyl glycerols. In other aspects, embodiments disclosed herein relate to processes for the production of 25 fatty acid methyl ester (FAME) -based biodiesel with the production of triisobutyl glycerols.

Referring now to Figure 1, a process 10 for producing fatty acid alkyl ester (FAME) -based biodiesel and producing tri-isoalkyl glycerols (such as TIG) according to embodiments disclosed herein is illustrated. A triglyceride-containing bio-oil may be fed through flow line 12 to transesterification reaction zone 14. In parallel, a tertiary alkyl ether (such as MTBE, ETBE, etc.) may be fed through flow line 16. to decomposition reaction zone 18, where tertiary alkyl ether can be decomposed to form an alcohol and an isoolefin.

Decomposition products can then be separated into an alcohol fraction and an isoolefin fraction, recovered through flow lines 20 and 22, respectively. Alcohol may be fed through flow line 20 to transesterification reaction zone 14. In transesterification reaction zone 14, at least a portion of the fats, oils or waxes present in the biomaterial is reacted with overheated water and / or alcohol under conditions of sufficient pressure, temperature and time to transesterify the reactants to produce fatty acid carboxylic acids, fatty acid alkyl esters and glycerols as co-product. The alkyl products of fatty acid (esters and carboxylic acids), glycerol and unreacted alcohol can then be separated and recovered by flow lines 24, 26 and 28, respectively.

Unreacted alcohol recovered through flow line 28 can be recycled to transesterification reaction zone 14 for reuse. If it is necessary to maintain the desired stoichiometric ratio of alcohol for triglyceride transesterification in reaction zone 14, additional alcohol and / or water may be fed to transesterification reaction zone 14 via the flow line.

Glycerol as a co-product recovered through flow line 26 and isoolefin recovered through flow line 22, then be fed to an etherification reaction zone 32. In the etherification reaction zone 32, glycerol and isoolefin may be be reacted in the presence of a glycerol etherification catalyst to produce tri-isoalkyl, which may be recovered via flow line 34. If necessary, unreacted isoolefin may be separated from the reaction product and recycled to the etherification reaction zone. 32 for reuse.

Tri-isoalkyl glycerol recovered through flow line 34, and alkyl fatty acid ester recovered through flow line 24 can then be used independently as biodiesel fuels or fuel additives. As illustrated, the tri-isoalkyl glycerol and alkyl fatty acid ester may be combined to form a biodiesel fuel or biodiesel fuel additive stream 36.

In some embodiments, the alkyl ether alkyl

tertiary feed to decomposition reaction zone 18 may include tertiary methyl butyl ether (MTBE). MTBE production facilities currently exist in many refineries. In addition, it is desired to remove MTBE from the gasoline pool. Processes according to embodiments disclosed herein may therefore provide one or more of a) an output to the MTBE, when necessary or desired, b) a convenient and economical way to transport the raw materials (alcohol and isoolefin). in the form of alkyl

30 tertiary ether) in the stoichiometric ratio required for the transesterification and etherification reaction zones 14, 32 and, c) transformation of the glycerols produced during the biofuel or biofuel additive transesterification reaction, among other benefits.

Regarding the decomposition of alkyl ethers

tertiary, one or more tertiary alkyl ethers may be fed into the decomposition reaction zone, and may in some embodiments be selected based on the resulting alcohol and / or isoolefin for use in the etherification and transesterification reaction zones. Tertiary alkyl ethers which may be used in embodiments disclosed herein may include tertiary ethyl butyl ether (MTBE), tertiary ethyl butyl ether (ETBE), tertiary amyl methyl ether (TAME) and amyl ethyl tertiary ether (TAEE), among others. Preferably, the resulting alcohol and olefins are readily separable. The decomposition reaction (also referred to as a dehydration or cracking reaction) may be performed in one or more fixed bed reactors in the presence of a catalyst. The addition of water or a tertiary alcohol (such as TBA, used as an equivalent of water, decomposing into an isoolefin and water) to a tertiary alkyl ether feed stream, for example, may be beneficial in suppressing undesirable side reactions. Other water equivalents may also be used. Examples of fixed bed reactors useful in

embodiments disclosed herein may include tubular reactor systems, boiling point reactors, bubble column reactors, traditional fixed bed reactors, catalytic distillation column reactors, pulsed flow reactors, and combinations thereof. One or more reactors may be used in the series flow or parallel flow, and each reactor may include one or more reaction zones containing one or more suitable decomposition catalysts.

Within the scope of this application, the term "

catalytic distillation reactor "means an apparatus in which the catalytic reaction and product separation take place at least partially simultaneously. The apparatus may include a conventional catalytic distillation column reactor, where reaction and distillation take place concurrently under boiling conditions, or a distillation column combined with at least one secondary reactor, where the secondary reactor may be operated as a liquid phase reactor or a boiling point reactor.While both described catalytic distillation reactor systems may be preferred over a reactor reaction. Conventional liquid phase followed by separations, a catalytic distillation column reactor can have the advantages of part number counting, reduced capital cost, increased catalyst productivity per kilo of catalyst, efficient heat removal (reaction heat may be absorbed in the vaporizing heat of the mix), and a potential to change the balance. Split wall distillation columns, where at least one section of the split wall column contains a catalytic distillation structure, may also be used, and are considered "catalytic distillation reactor systems" here.

Suitable catalysts for use in the decomposition reaction zone of the processes disclosed herein may include any decomposition catalyst. In some embodiments, the decomposition catalyst may include a selectively poisoned HF-treated amorphous synthetic alumina-silica catalyst as disclosed in US Patent Application Serial No. 12 / 260,729, which is required by the applicant of the present disclosure and which is incorporated herein by reference.

Reactions may be carried out in the vapor phase, liquid phase or double phase liquid and vapor phase. Due to the nature of equilibrium reactions, performing vapor phase or vapor phase and liquid phase reactions may result in higher pass conversion or higher olefin productivity than a liquid phase reaction, which may also require higher pressure.

Decomposition reaction conditions may vary depending on the feed mixture used and the desired olefins produced. Decomposition temperatures may range from 100 ° C to 500 ° C in some embodiments; 130-350 ° C in other embodiments and from 150 ° C to 300 ° C in still other embodiments. The decomposition reaction may be performed under pressures in the range 1-22 bar (0-300 psig) (100 to 2,200 kPag) in some embodiments, 1-11 bar (0-150 psig) (100 to 1,100 kPag), other modalities. In some embodiments, the pressure is maintained such that the olefin as product is in the liquid phase or partially in the liquid phase at the reaction temperature used. The net hourly space velocity (LHSV) (the volume of liquid per catalyst volume per hour) at which the reaction is performed may be within the range of 0.5-200 h "1 in some modalities, 1-50 h" 1 in other embodiments and 1-10 h "1 still 30 in other embodiments. Separation of the decomposition products can be accomplished through one or more series or parallel separators. When a distillation column reactor system is used, the Product separation may be carried out simultaneously with the reaction Separators useful in embodiments disclosed herein may include distillation, liquid-liquid separation, extraction, separation or other processes known to those skilled in the art.

For example, in some embodiments, a decomposition reactor effluent may be fed to a first distillation column to separate and recover the isoolefins. For example, isobutylene may be separated from unreacted MTBE, methanol, and any heavy agents, recovering a higher isobutylene rich fraction. The isobutylene-rich upper fractions, in some embodiments, may be a high purity isoolefin stream with an isoolefin concentration of at least 99.5 weight percent. Unreacted MTBE, methanol and heavy agents can be recovered as a lower fraction of the first distillation column and fed with a second distillation column, which unreacted MTBE can be separated from the heavy agent and methanol. Unreacted MTBE can be recovered as a higher fraction rich in MTBE, a part that can be recycled to decomposition reaction zone 18 in some embodiments. The heavy agent and methanol may be recovered as a lower fraction of the second distillation column. Methanol may then be separated from the heavy agents, such as feeding the heavy agents and methanol to a third 30 distillation column. A methanol-rich upper fraction and a heavy-agent lower fraction can be recovered, where methanol-rich upper fractions can be fed to a transesterification reaction zone 14.

In the transesterification reaction zone, a fat

or oil is reacted with an alcohol (such as methanol or ethanol) in the presence of a catalyst to effect exchange of natural esters such as glyceride with the primary alcohol to produce glycerol and fatty acid alkyl esters such as FAME, the latter of which forms biodiesel. In the process described herein, the alcohol (e.g. methanol) for feeding the transesterification process is received as a tertiary alkyl ether decomposition product (e.g. MTBE).

Raw materials for fuel production

Alkyl-based biodiesel fatty acid esters and fuel additives such as FAME may include vegetable oils and animal fats, which are higher fatty acid esters. The term fat (animal or vegetable oil, if liquid) is usually confined to fatty acid esters (glycerides) with glycerol, and the term wax to esters of other alcohols. Since natural vegetable oils may contain several minor amounts of free fatty acids, free fatty acids may be removed by pretreatment prior to performing the transesterification reaction with an alcohol.

The basic chemistry involved in biodiesel production is the reaction of catalytic exchange of natural esters (mainly glycerides) with a primary alcohol (usually methanol or ethanol). An alcoholic solution of a base (usually NaOH, KOH, potassium methoxide, or sodium methoxide) can be used as a catalyst. Therefore, biodiesel is a mixture of methyl or ethyl esters of various saturated and unsaturated fatty acids. Co-product is glycerol, which represents 16-25% by weight. Biodiesel may also contain some fatty acids (ester hydrolysis products) in small quantities, depending on the amount of water in the feed or the catalyst used.

Glyceride Glycerol Fatty Acid Ester

CH-O-COR1 CH2-OH

| Base I

CH-O-COR2 + 3 R4OH -► CH-OH + 3 R-COOR4

| Catalyst j

CH-O-COR3 CH2-OH

where R4OH = methanol or ethanol; R = R1, R2 or R3.

The alkyl groups R1, R2 and R3 of the glyceride as a natural product are generally different in chain length and degree of unsaturation. Alkyl groups are generally straight chain and have even number of carbon atoms from 4 to 26. The exception is branched isovaleric acid (Ch3) 2CHCH2COOH, which occurs in relatively large amounts of dolphins. Some unsaturated fatty acids have two or three double bonds in the alkyl chains. Unsaturated fatty acids have lower melting points than their saturated counterparts. The chain length of unsaturated fatty acids is generally in the range of C 10 -C 24. Canola oil has a higher degree of unsaturation at the C16 -C20 chain length than corn oil. In general, basic catalysts are more effective for transesterification of carboxylic esters with an alcohol than acid catalysts. Suitable catalysts for use in the transesterification reaction zone of the processes disclosed herein may include any heterogeneous transesterification catalyst, used as a fixed bed, moving bed, or suspension, or may be a homogeneous catalyst, co-fed with the reagents. In some embodiments, the transesterification catalyst may include a heterogeneous transesterification catalyst.

where a transesterification catalyst is homogeneous is fed to the reagents at low concentrations (between 0.1 and 150 ppm), as disclosed in US Patent Application Serial No. 12 / 029,283, required by the applicant of the present disclosure; which is incorporated herein by reference.

Heterogeneous catalysts useful for

Transesterification of vegetable oils and animal fats may include catalysts may include metal oxides such as magnesium oxide, calcium oxide, zinc oxide, sodium oxide, potassium oxide,

20 lanthanum, etc., supported on a support such as

silica, alumina and carbon / or carbonaceous material. Carbon and carbonaceous support will preferably be surface functional groups such as hydroxyl or carbonyl or both to immobilize organometallic compounds in the

support surface. The total amount of the metal or active metal components on a solid metal alkoxide, metal hydroxide or metal oxide catalysts is from about 0.05 wt% to about 20 wt% in some embodiments, and about 0.07% by weight to about 12% by weight

30 The weight of other modalities. Examples of solid (homogeneous) catalytic compounds include zinc 2-methoxyethoxide, calcium 2-methoxyethoxide, zinc 2-methoxypropoxide, zinc ethoxide, zinc carbonate, alkyl alkoxy, calcium 2-methoxyproxide, calcium ethoxide, methoxide calcium hydroxide, alkyl calcium alkoxide carbonate, magnesium 2-methoxyethoxide, magnesium 2-methoxyproxide, magnesium ethoxide, magnesium methoxide, magnesium butoxide, alkyl magnesium alkoxy carbonate, lanthanum alkoxide, alkylanthoxyl carbonate, zinc salts of carboxylic acids, magnesium salts of carboxylic acids, calcium salts of carboxylic acids and glycerides of Mg, Ca, Zn, among others. The mixture of these can also be used. Soluble compounds of Ca, Mg, Zn and La may be obtained by reacting oxide or hydroxide of this metal with a carbonate or organic or a mixture of organic carbonate and an alcohol or carboxylic acids or a mixture of organic carboxylic acid and an alcohol, such as methanol, 2-methoxyethanol, etc. at a temperature of 930 ° C to 260 ° C (200 ° F to 500 ° F), preferably 121 ° C to 232 ° C (250 ° F to 450 ° F) in liquid phase or presence of liquid and steam. Such prepared solutions are useful for catalyzing the transesterification reaction (when used at a sufficient concentration). Such prepared solutions are also useful for

2 5 the addition of a small amount of these metals to the

feed a reactor to obtain a long catalyst cycle time. The heterogeneous catalysts disclosed herein are usually also basic catalysts.

Initially, the transesterification process, from

30 Raw materials, water and any additional reagents, solvents, catalysts and other optional components may be introduced into a transesterification reaction zone. This introduction to the transesterification reaction zone may be by any means known to those skilled in the art for the transport of solids, liquids or mixed phase compositions. In some embodiments, for example, the raw material may be introduced through a funnel. In other embodiments, the feedstock may be introduced into the reaction zone of

transesterification via a power line or conduit. Contact of components within the transesterification reaction zone may be effected by countercurrent flow, continuous or intermittent agitation, static mixing, or by other means known in the art.

The transesterification reaction can be performed in

one or more reactors in the presence of one or more homogeneous and / or heterogeneous catalysts as described above. When homogeneous catalysts are used, the homogeneous catalyst may be further separated from the

20 The reactor effluent is recycled if desired or required.

for product specifications. Examples of transesterification reactors useful in embodiments disclosed herein may include tubular reactors, boiling point reactors, bubble column reactors, bed reactors.

traditional fixed, catalytic distillation column reactors, split wall distillation column reactors, pulsed flow reactors, and combinations thereof. One or more reactors may be used in parallel flow or in series flow, and each reactor may include one or more

30 reaction zones for contacting reagents with one or more suitable transesterification catalysts.

Once introduced into the transesterification reaction zone, the reagents are contacted under conditions of sufficient temperature and pressure to convert at least some of the triglycerides in the feedstock to carboxylic acids and glycerol. The feedstock is allowed to remain in the reaction zone long enough to convert at least some triglycerides in the feedstock to carboxylic acids and glycerol, and such reaction times may be obtained by batch, semi-batch or continuous processes. . In addition to alcohol reagents, water can be fed as a transesterification reagent, reacting with fats, oils and waxes to produce carboxylic acids and glycerol. For example, water may be brought into the transesterification reaction zone, and / or water, fed as a reaction modifier or resulting from the decomposition of an equivalent of water and recovered from the decomposition of tertiary alkyl ethers, may be introduced as a reagent for the transesterification reaction zone. When water is used, the transesterification reaction shown above is illustrative, where R4 = hydrogen.

The temperatures used in the transesterification reactor may range from about 150 ° C to 500 ° C.

2 5 In other embodiments, operating temperatures may

range from about 200 ° C to 450 ° C. The pressure in the transesterification reactor must be sufficiently high to maintain water in liquid phase or liquid-type viscosity as at elevated operating temperatures (eg

30 (for example, when operating at temperatures above the supercritical water temperature, 374 ° C).

In some embodiments, water, in addition to acting as a reactant and a solvent, can also serve as a catalyst. Under reaction conditions in the transesterification reactor, liquid water may be considered to be quite acidic or basic due to the high water ionization constant (Kw) than at room temperature or boiling. This can lead to increased hydrogen bonding acidity, which may in turn result in increased acidity at these elevated temperatures. Kw is known to be very temperature dependent, and tends to increase with temperature (ie 0.001 χ 10 "14 mol2 l" 2, at -35 ° C (pH 8.5), 0.112 χ 10 "14 mol2 1 "2 at 0 ° C (pH 7.5), 0.991 χ 10" 14 mol2 l'2, at 25 ° C (pH 7.0), 9.311 χ 10 "14 mol2 l" 2 at 60 ° C (pH 6.5)) for 1012 mol2 1.2 at 300 ° C (pH 6.0 ~ 50 MPa). As such, liquid water can be at least partially ionized, and the acidic protons (H + / H30 +) of water can catalyze the reaction by donating a proton to the triglyceride carbonyl group, making it more reactive. This activated triglyceride is therefore more susceptible to nucleophilic attack. Water ionization also generates a basic hydroxyl (OH ") group which can also catalyze the triglyceride nucleophilic attack transesterification reaction.

Water under conditions in the reaction zone of

transesterification may further serve as an effective catalyst for hydrolysis and degradation of carbohydrates such as starch, cellulose or glycerol. Thus, solid materials fed together with fats, oils and waxes can be converted to biofuels at the same time in some embodiments.

After converting at least a portion of the triglycerides to carboxylic acids, esters and glycerol, the reaction mixture is removed or recovered from the transesterification reactor, depending on the type of process used. At this point, the reactor effluent includes one or more carboxylic acids, esters, glycerols,

monoglycerides, diglycerides, triglycerides, and unreacted raw material and transesterification reagent (water or alcohol).

The transesterification reactor effluent mixture may then be separated, such as by distillation, liquid-liquid separations, extraction, separation or other processes known to those skilled in the art. Transesterification reactor effluent may include one or more of hydrocarbons, FAME, other esters, carboxylic acids, glycerols, monoglycerides, diglycerides, triglycerides, water, alcohol and low boiling solvents. Transesterification reactor effluent can be passed

20 through a separation zone where water is removed

from the fluid phase organic components and light materials such as low boiling solvents, unreacted alcohols or various reaction by-products can be recovered. In addition, glycerol can be separated from reactor effluent as a byproduct of the transesterification reaction. The remaining mixture may be composed primarily of fatty acid alkyl esters, which may be used as a biodiesel additive or biofuel, or may be hydrotreated to improve the quality of the product.

3 0 or to remove some oxygen from biodiesel as a product.

Glycerol as a byproduct derived from the transesterification reaction zone is fed, together with isoolefin (eg isobutene), a tertiary alkyl ether decomposition process (e.g. MTBE), into the etherification reaction zone. In the etherification reaction zone, glycerol is reacted with isobutylene to form a mono-tertiary alkyl glycerol, tertiary alkyl glycerol and tri-tertiary alkyl glycerol (e.g. TIG) product. Feeding of isoolefin at higher than stoichiometric ratios may favor the production of desired di-tertiary alkyl glycerol and tri-isoalkyl glycerol products. The acid catalyzed reaction of glycerol and isobutylene occurs in a reactor, which may be, for example, a continuous stirred tank reactor. Acid catalyst can also be fed to the reactor as needed.

The acid catalyst used in the etherification reaction zone may be, for example, homogeneous catalysts (e.g. p-toluene sulfonic acid, methane sulfonic acid, sulfuric acid and sulfonic acid) and / or heterogeneous catalysts or large porous zeolite catalysts. Isobutylene and glycerol are substantially immiscible and with appropriate agitation form two phases, a polar glycerol phase and an isoolefin phase. The homogeneous acid catalyst is mainly contained in the glycerol phase. There is some dissolved isobutylene in the glycerol phase and most of the etherification reaction occurs in this phase. Mass transfer 30 from the isobutylene phase to the glycerol phase maintains the isobutene supply in the glycerol phase.

Mono-tertiary butyl glycerol formed in the glycerol phase will remain mainly in this phase. However, di- and tri-tertiary alkyl products will preferably transfer to the isobutylene phase.

The etherification reaction effluents may then be separated to recover unreacted reagents and desired biofuel products. In some embodiments, the etherification reaction mixture may be sent to a distiller to separate into a higher isoalkylene phase composed of mono-tertiary alkyl glycerol, tertiary alkyl glycerol and tri-tertiary alkyl glycerol in addition to unreacted isoolefin, and a lower glycerol phase composed of glycerol, mono-tertiary alkyl glycerol, catalyst and small amounts of glycerol and tri-tertiary alkyl glycerol.

In some embodiments, the glycerol phase may be returned to the liquid feed glycerol reactor and constitute the catalyst. In addition, the phase of

2 0 isobutylene can continue to an extraction column,

where unreacted isoolefin is extracted as a higher fraction and returned to the reactor along with isoolefin from the liquid feed. The lower fraction of the distillation column comprises a small amount of catalyst, glycerol and mono-tertiary alkyl glycerol, as well as alkyl tertiary glycerol and tri-tertiary alkyl glycerol products. The lower fraction may be contacted with water to extract the glycerol, catalyst and mono-tertiary alkyl glycerol for recovery,

3 0 recycling or disposal. Di- and tertiary alkyl glycerol product is recovered for use as a biofuel or biofuel additive. In some embodiments, di- and tertiary alkyl glycerol may be combined with alkyl fatty acid esters for use as a biofuel or biofuel additive.

It is typically necessary that the etherification liquid feed comprises at least one mol to four moles of isoolefin per mol of glycerol. Higher isoolefin concentration usually results in higher triether ethers production. It is also common for the reaction mixture in the etherification reaction zone to be maintained such that the polar glycerol phase comprises at least 30% by weight of the total reaction mixture, and that the glycerol content of the polar glycerol phase comprises, at least 50 wt% and preferably at least 60 wt% of the polar phase. Reaction conditions that are employed for etherification are temperatures of 40 ° C - 150 ° C, preferably about 500 ° C - 100 ° C. The pressures are sufficient to maintain the liquid phase, for example about 2 to 20 bar (about 15 to 300 psig) (200 to 2,000 kPa). Homogeneous catalysts, when used, are generally used in amounts of about 0.1 - 5.0% by weight of the reaction mixture, preferably about 0.5-2.5%.

Typical glycerol and isobutylene etherification processes to produce TIG require the importation of high purity glycerol and isobutylene, increasing process costs. In addition, typical processes for transesterification of triglyceride bio-oils and fats require the importation of methanol and other raw materials. Modalities disclosed herein may advantageously integrate decomposition of the ethers with the production of biodiesel fuels or fuel additives by transesterification and etherification of reaction raw materials and by-products, as described above. This integration provides isools and alcohols in the required stoichiometric ratio, and can eliminate the need to import alcohol, glycerol and isools.

In addition, MTBE is produced or already capable of being produced in many oil refineries and petrochemical facilities. Processes for producing biodiesel in accordance with embodiments disclosed herein may provide an output for MTBE and may also be used to employ idle equipment. As the use of MTBE as a fuel additive is currently being phased out in many countries due to practical and environmental issues, processes revealed here provide a viable alternative use for existing MTBE production facilities. MTBE is a convenient and economical way to transport

20 isobutylene and methanol (in the correct ratio) from the

oil or other facilities to produce MTBE for the biodiesel plant for use as feedstock for the transesterification and etherification processes.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of such disclosure, will find that other embodiments may be conceived which do not depart from the scope of the invention as disclosed herein. Thus, the scope of the invention should be limited only by

30 attached claims.

Claims (25)

Process for the production of a biodiesel fuel, characterized in that it comprises: feeding a tertiary alkyl ether to a decomposition reaction zone containing at least one decomposition catalyst; contacting the tertiary alkyl ether with at least one decomposition catalyst at a temperature and pressure to decompose the tertiary alkyl ether into an alcohol and an isoolefin; separating the alcohol and isoolefin to recover a fraction comprising the alcohol and a fraction comprising the isoolefin; feeding at least a portion of the alcohol-comprising moiety and at least one of a vegetable oil and animal fat to a transesterification reaction zone; contacting the alcohol and at least one of a vegetable oil and an animal fat in the presence of at least one transesterification catalyst under conditions of sufficient temperature and pressure to transesterify the vegetable oil or animal fat to form a transesterification product comprising alkyl acid esters. fatty and glycerol; separating the transesterification product to recover a fraction comprising the alkyl fatty acid esters and a fraction comprising glycerol; feeding at least a part of the glycerol-comprising fraction, and at least a part of the isoolefin-containing fraction to an etherification reaction zone; contacting isoolefin and glycerol in the presence of at least one etherification catalyst under temperature and pressure conditions to form an etherification product comprising at least one of mono-tertiary alkyl glycerol, tertiary alkyl glycerol, and tri-alkyl glycerol. -tertiary; separating the product from etherification to recover a moiety comprising tertiary alkyl glycerol and tri tertiary alkyl glycerol. Process according to Claim 1, characterized in that it further comprises using at least a fraction comprising tertiary alkyl glycerol and tri-tertiary alkyl glycerol and the fraction comprising fatty acid alkyl esters to form a biodiesel fuel or a biodiesel fuel additive. Process according to either of Claims 1 and 2, characterized in that it further comprises combining at least a part of the moiety comprising di-tertiary alkyl glycerol and tri-tertiary alkyl glycerol and at least a part of the fraction comprising the fatty acid alkyl esters to form a biodiesel fuel or a biodiesel fuel additive. Process according to any one of claims 1, 2 or 3, characterized in that the tertiary alkyl ether comprises at least one tertiary methyl butyl ether, tertiary ethyl butyl ether, tertiary amyl methyl ether and tertiary amyl ethyl ether. , the alcohol comprises at least one of methanol and ethanol, and isoolefin comprises at least one of isobutylene and isoamylenes. Process according to any one of claims 1, 2, 3 or 4, characterized in that the tertiary alkyl ether comprises tertiary methyl butyl ether, isoolefin comprises isobutylene, and alcohol comprises methanol. Process according to any one of claims 1, 2, 3, 4 or 5, characterized in that the fraction comprising isoolefin has a purity of at least 99.5% by weight of isoolefin. Process according to any one of claims 1, 2, 3, 4, 5 or 6, characterized in that the contact with the tertiary alkyl ether and the separation of alcohol and isoolefin are carried out simultaneously in a reactor system. catalytic distillation. Process according to any one of claims 1, 2, 3, 4, 5, 6 or 7, characterized in that it further comprises feeding at least one water and water equivalent to the decomposition reaction zone. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that the decomposition catalyst comprises at least one of a heterogeneous decomposition catalyst, a catalyst of homogeneous decomposition, and their combinations. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8 or 9, characterized in that it further comprises feeding a carbohydrate into the transesterification reaction zone. Process according to any one of Claims 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, characterized in that the vegetable oil comprises at least one canola oil and corn oil . Process according to any one of Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, characterized in that contact with alcohol and separation of the transesterification product are performed simultaneously on a catalytic distillation reactor system. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, characterized in that the transesterification catalyst is at least one of a heterogeneous decomposition catalyst, a homogeneous decomposition catalyst, and combinations thereof. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, characterized in that the etherification catalyst comprises at least one of a heterogeneous decomposition catalyst, a homogeneous decomposition catalyst, and combinations thereof. 15. Process for the production of a biodiesel fuel, characterized in that: feed a tertiary methyl butyl ether to a decomposition reaction zone containing at least one decomposition catalyst; contacting tertiary methyl butyl ether with at least one decomposition catalyst at a temperature and pressure to decompose tertiary methyl butyl ether in methanol and isobutylene; separating methanol and isobutylene to recover a fraction comprising methanol and a fraction comprising isobutylene; feeding at least a portion of the fraction comprising methanol, and at least one of a vegetable oil and animal fat to a transesterification reaction zone; contacting methanol and at least one of a vegetable oil and an animal fat in the presence of at least one transesterification catalyst under conditions of sufficient temperature and pressure to transesterify the vegetable oil or animal fat to form a transesterification product comprising methyl acid esters. fatty and glycerol; separating the transesterification product to recover a fraction comprising the fatty acid methyl esters and a fraction comprising glycerol; feeding at least a portion of the glycerol-comprising fraction, and at least a portion of the isobutylene-comprising fraction to an etherification reaction zone; contacting isobutylene and glycerol in the presence of at least one etherification catalyst under temperature and pressure conditions to form an etherification product comprising at least one of tertiary butyl glycerol, tertiary butyl glycerol, and tri butyl glycerol -tertiary; separating the product from etherification to recover a fraction comprising tertiary butyl glycerol and tri-tertiary butyl glycerol. Process according to Claim 15, characterized in that it further comprises using at least one fraction comprising tertiary butyl glycerol and tri-tertiary butyl glycerol and the fraction comprising fatty acid methyl esters to form a fuel. biodiesel or a biodiesel fuel additive. Process according to any one of claims 15 or 16, characterized in that the fraction comprising isobutylene has a purity of at least 99.5% by weight of isobutylene. Process according to any one of claims 15, 16 or 17, characterized in that contact with methyl butyl tertiary ether and separation of methanol and isobutylene are carried out simultaneously in a catalytic distillation reactor system. Process according to any one of claims 15, 16, 17 or 18, characterized in that it further comprises feeding at least one water and one water equivalent to the decomposition reaction zone. Process according to any one of claims 15, 16, 17, 18 or 19, characterized in that the decomposition catalyst comprises at least one of a heterogeneous decomposition catalyst, a homogeneous decomposition catalyst, and combinations thereof. . Process according to any one of claims 15, 16, 17, 18, 19 or 20, characterized in that it further comprises feeding a carbohydrate into the transesterification reaction zone. Process according to any one of claims 15, 16, 17, 18, 19, 20 or 21, characterized in that the contact with methanol and the separation of the transesterification product are carried out simultaneously in a reactor system. catalytic distillation. Process according to any one of claims 15, 16, 17, 18, 19, 20, 21 or 22, characterized in that the vegetable oil comprises at least one canola oil and corn oil. Process according to any one of claims 15, 16, 17, 18, 19, 20, 21, 22 or 23, characterized in that the transesterification catalyst comprises at least one of a heterogeneous decomposition catalyst, a catalyst of homogeneous decomposition, and their combinations. Process according to any one of claims 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24, characterized in that the etherification catalyst comprises at least one of a heterogeneous decomposition catalyst. , a homogeneous decomposition catalyst, and combinations thereof.