BR102012006421B1 - BIOKEROSENE PRODUCTION PROCESS IN INTEGRATED ROUTE AND BIOKEROSENES OBTAINED THUS - Google Patents

Abstract

BIOKEROSENE PRODUCTION PROCESS IN INTEGRATED ROUTE AND BIOKEROSENES OBTAINED THE WAY The present invention describes the process for obtaining two fuels compatible with kerosene of fossil origin. The first fuel consists of a mixture of esters with a high degree of purity, the second fuel consists of a mixture of hydrocarbons with characteristics similar to kerosene of fossil origin.

Description

field of invention

The present patent application refers to two subsequent processes for the production of biokerosene, which correspond to fuels of vegetable origin with characteristics and/or properties similar to those of kerosene of fossil origin. The first process originates a fuel consisting of a mixture of esters. The second process makes it possible to obtain a product consisting of hydrocarbons, with a composition similar to kerosene of fossil origin. It is noteworthy that both processes originate low-cost biofuels.

It has industrial applicability aimed at companies producing ethanol and/or biofuels. This technology is included in the market for biofuels and fuels from renewable sources.

Fundamentals of the invention

Kerosene is a fossil fuel responsible for emissions of pollutants harmful to the environment. The local environmental impacts generated by air activity are varied. They range from soil and water pollution to noise and local air quality issues. In this sense, this technology presents the obtainment of fuels of vegetable origin, alternative to aviation kerosene that aims to reduce pollutant emissions and has low toxicity.

Kerosene, also called illuminating oil or paraffin oil, is a liquid resulting from the fractional distillation of petroleum, with a boiling temperature between 150 and 290 degrees Celsius, a fraction between gasoline and diesel oil. It is a complex combination of hydrocarbons (aliphatic, naphthenic and aromatic) with a number of carbons mostly within the range of C9 to C16, produced by distillation of crude oil, with a distillation range between 150°C and 239°C.

Biodiesel is defined by the American Society for Testing Materials (ASTM) as a synthetic liquid fuel, originating from renewable raw materials and consisting of a mixture of alkyl esters of long-chain fatty acids, derived from vegetable oils or animal fats.

The frequent increase in oil prices and the possibility of depletion of fossil fuels have been motivating countless researchers to search for an alternative fuel. This concern also exists on the part of environmentalists in order to reduce pollution caused by the use of diesel and was intensified after the Kyoto Protocol.

The use of biodiesel as a fuel has shown promising potential worldwide, being a market that is growing rapidly due to numerous advantages, such as: - it is a fuel produced from renewable sources, such as vegetable oils, frying residues or animal fat . The use of waste as raw material reduces the costs of sewage treatment and waste disposal. - is biodegradable. Studies show that soybean oil and canola biodiesel are easily absorbed by the environment. The use of mixtures containing 20% v/v of biodiesel (B20) increases the biodegradability of diesel in the presence of water. In addition, algae growth was observed in biodiesel storage tanks. - it is a non-toxic fuel, as the use of biodiesel causes a substantial reduction in the emission of carbon monoxide and particulate matter. In addition, it is free of sulfur and aromatics, prevents the formation of soot, as it has 10% v/v of oxygen. The use of 20% v/v of biodiesel to diesel reduces carbon dioxide emissions by 15.66% v/v.

Some technologies present the production process of hydrocarbons from renewable sources. In patent US6,987,79 B2, biomass was used as raw material for the production of synthesis gas. Synthesis gas is produced through a process called Solene's plasma gasification vitrification (SPGV) technology. Then, through the Fischer Tropsch process (F-T synthesis) biodiesel, naphtha and biokerosene are obtained. This technology is more expensive than the proposed technology, because it uses plasma, among other technologies that increase the cost of production, making a large-scale system unfeasible.

Technologies US0264061A1/ 0111599A1 and AU2010201903-A1 use biomass (wood) as raw material for the production of fuels, by Fischer Tropsch. The main drawback of these technologies is that most of the products obtained have characteristics similar to diesel and not kerosene. The technology US0015459A1/ 0105814A1/ 0092724A1 performs the production of hydrocarbons from fatty acids and esters. In this process, a series of reactions occur (hydrogenation, ketonization, hydrodeoxygenation, isomerization), which cause an increase in the cost of the process. These reactions transform triglycerides, esters, fatty acids into hydrocarbons.

US7589243 uses raw material from biomass and differs from the order requested here which uses raw material consisting of fatty acids and/or triacylglycerols. The advantage of the proposed process is the low cost and faster production, which would facilitate a continuous process.

US7,915,460B2 produces hydrocarbons through hydrogenation, decarboxylation and hydrodeoxygenation. Process can be used for vegetable oils, fat and sludge. Flexible process, as it can be used for various raw materials. Disadvantage: the formation of compounds with high molecular weight may occur, causing the deactivation of catalysts.

The US7,972,392 B2 technology uses biomass as raw material and converts it into hydrocarbons from C5-C11 hydrocarbons and C2-C8 alcohols through biomass gasification and Fischer Tropsch. Process with high cost compared to proposed technology. US 0215137A1 Uses fermentation to transform sugars into biofuels, the product obtained has the characteristic of alcohols. This technology uses a long and unfeasible biofuel production route. In addition, it produces alcohols that cannot be used in aircraft, as they have characteristics different from fossil kerosene and are expensive.

Patents JPO 2011052077-A/W02011025002-A1 present the production of biokerosene from vegetable oils, animal fat and other raw materials containing glycerides and oxygen through dehydrogenation and hydrogenation. These inventions use bifunctional catalysts containing metal from group 8 of the periodic table. The process has a higher cost than the technology proposed here.

The great advantage of this process as a whole is that it does not require cyclization (reformation reaction, as in other existing biokerosene production processes) and the next step of hydrogenation (hydrocracking) is only used in the final phase, and in a small percentage of material in relation to the original raw material. In the patented processes, all the raw material is hydrogenated, making the processes more expensive and difficult.

The use of esters in the decarboxylation step is extremely important, as it is possible to obtain the reaction under mild process conditions, with minimal coke generation and obtaining hydrocarbons in the kerosene range, that is, between C9 to C16, and with compounds cycles, a fact that is difficult to use vegetable oils in the form of triacylglycerols, requiring much higher operating temperatures and significant coke formation.

Brief description of the invention

The present patent application describes the production of two biofuels that are alternatives to kerosene of fossil origin. An oxygenated fuel, consisting of a mixture of esters with high purity and similar characteristics to kerosene. This fuel can be used in blends with fossil kerosene, or pure using antifreeze.

Briefly, vegetable oils, preferably those richer in short-chain fatty acids, are subjected to a transesterification process, and then the glycerin and alcohol are separated. In the next step, biokerosene (oxygenated) is obtained through molecular distillation, which separates it very efficiently and with a high degree of purity.

The glycerin obtained here can be processed to produce higher value-added products, such as ethanol.

The second fuel obtained in this process consists of a mixture of hydrocarbons with linear and cyclic chains, which has a composition similar to that of fossil kerosene. They can be used in blends or pure, without the need to use antifreeze.

Briefly, the by-products obtained in the previous step are subjected to a decarbonylation reaction, obtaining hydrocarbons and oxygenated hydrocarbons. After separating these two classes of products by distillation, the pure hydrocarbons are obtained, which is biokerosene in the form of hydrocarbons, and also the heavier compounds, which are the oxygenated ones, which are sent to the next processing step for the decarboxylation reaction (or hydrogenation). After hydrogenation, another stream of hydrocarbons is obtained which, depending on the operating conditions, can be either biokerosene or biogasoline.

Alternatively, this stage could have started with raw material from the esters obtained after transesterification, without going through molecular distillation which, in this case, would not obtain, therefore, the oxygenated biokerosenes of that stage.

Brief description of the figure

Figure 1 shows a flowchart of the process for obtaining biokerosene in order to detail the sequence of reactions that occur in the invention, as well as the purification steps of the products obtained.

Detailed description of the invention

The present patent application refers to two processes for the production of biokerosene, which correspond to two fuels of vegetable origin with characteristics and/or properties similar to those of kerosene of fossil origin. The first process originates a fuel consisting of a mixture of esters, here it will be called type 1 biokerosene [biokerosene (1)]. The second process makes it possible to obtain a product consisting of hydrocarbons, with a composition similar to kerosene of fossil origin, which will be called biokerosene type 2 [biokerosene (2)]. It should be noted that both processes originate a low-cost substitute for kerosene of fossil origin.

Figure 1 presents a process flowchart that describes the sequence of reactions that occur in this process.

Initially, the raw material containing fatty acids is prepared, in the form of triglycerides, with fatty chains ranging from C8 to C22, and later mixtures of esters are obtained from transesterification, esterification, olefin acylation or aldehyde condensation reactions. It is noteworthy that the transesterification reaction provides greater conversion in less time, for this reason it will be preferably treated in this study, since this factor will contribute to reducing the cost of the process and will enable large-scale production in continuous processes.

This reaction can occur under different conditions of temperature and pressure, the specification of these conditions depends on the type of raw material and the type of equipment used in the reaction. Esters are normally produced using continuous batch stirring reactors (BSTR). Currently, several types of systems have been studied in order to increase the efficiency of these processes and, consequently, the production in a faster and more economical way. As examples of these systems, the following can be cited: continuous agitation reactors in series; reactive distillation; high-speed reactors; ultrasonic reactors; microwave; microreactors; reactors with thermal exchange plates; tubular reactors in series with continuous stirring reactors; column with ion-exchange resin; reactor with two phases (liquid-gaseous) at high temperatures; oscillatory reactors (Harvey, 2003).

Transesterification is normally carried out in reactors with continuous agitation, in the presence of basic catalysis and low molecular weight alcohols. The products of this reaction are 90 wt% esters and 10 wt% glycerin. Then, the esters can be separated using a high vacuum purification process, which makes it possible to obtain a mixture of low molecular weight esters (C < 16), with a high degree of purity (>99 wt.%), called of biokerosene (1). Another option is the use of esters as raw material for the production of hydrocarbons (see Figure 1), directly via HC. It is noteworthy that this process can occur at atmospheric pressure or under vacuum and between temperatures of 200 to 600°C.

Basically, to obtain biokerosene 1, the following steps must be followed: a) The raw material is prepared containing materials rich in glycerides, and at least one short-chain alcohol from C1 to C5, and at least one catalyst ( homogeneous and/or heterogeneous) performed at atmospheric pressure; b) The transesterification reaction is carried out (atmospheric pressure and temperature between ambient and up to 150°C); c) The product obtained is purified by high vacuum, with pressures of the order of 0.001 to 5 mmHg or 1.33.10'6 to 10'2 bar.

The residue from the distillation process consists of heavy esters (C > 16), this stream is subjected to the decarbonylation reaction carried out in fixed or fluidized bed reactors and in the presence of zeolites as catalysts. This reaction consists of heating the esters in a reactor (fixed or fluidized bed) supported or filled with zeolites at temperatures ranging from 150 to 600°C, preferably from 250 to 450°C, obtaining a mixture of hydrocarbons and oxygenated compounds containing approximately 50% of each stream.

The product of this reaction (mixture of hydrocarbons + oxygenated compounds) is subjected to a separation process, such as atmospheric distillation, obtaining a fraction consisting of hydrocarbons compatible with the composition of kerosene of fossil origin, these hydrocarbons are called biokerosene (2 ).

The stream consisting of oxygenated compounds is subjected to a decarboxylation and/or hydrogenation reaction in the presence of a commercial hydrogenation catalyst, and under pressure. Then, the product of this reaction is purified by distillation at atmospheric pressure, obtaining hydrocarbons, which are called biokerosene (2) and hydrocarbons with smaller chains (C < 9), which can be used as biogasoline. Depending on the operating conditions of the previous steps, such as conduction at lower or higher temperatures, they may increase or decrease the bikerosene yields, respectively.

It should be noted that both biokerosenes can be used in blends with kerosene of fossil origin, and since biokerosene (1) consists of a mixture of esters, antifreeze 15 should be added if used pure. Biokerosene (2) is similar to fossil fuel kerosene in terms of composition and physical properties. Table 1 - Properties of Biokerosene 1

The glycerin that is the by-product of the transesterification reaction can be used to obtain several chemical products. Among the main uses of glycerin are the cosmetics industry which absorbs 40% of all production, the food industry which uses 24%, the production of resins and esters uses 18% of glycerin, finally the pharmaceutical industry absorbs 11%, among other applications. In this study, it is intended to reuse glycerin in order to obtain ethanol, which will be used as raw material for the transesterification reaction. The reuse of glycerin aims to reduce the cost of the reaction, since it will be used in the production of one of the reagents of the transesterification reaction. In addition to reducing the cost of the process, the reuse of this by-product will contribute to reducing the generation of waste from the process. Considering that there is a surplus of glycerin on the market from the biodiesel production process, it is not feasible to commercialize this by-product.

Two processes can be used to produce ethanol from glycerin. These processes will be described below.

The first process consists of thermal degradation of glycerin, between 750°C and 900°C, to obtain synthesis gas (a mixture of carbon monoxide and hydrogen). Next, the synthesis gas is converted into ethanol through the reaction known as direct synthesis.

The second process consists of the fermentation of glycerin in the presence of the bacteria Escherichia Coli, resulting in a mixture of butanol and ethanol. The reaction will be described below.

Example of implementation

The conversions obtained in each stage of the process of obtaining biokerosene will be presented below. First step: Transesterification reaction (20 < T < 150°C), and preferably between 30 and 60°C. Conversion: 85 - 99% by weight. Second stage: Decarbonylation reaction (150 < T < 650°C) and preferably between 250 and 450°C Conversion: Approximately 50% by weight of hydrocarbons and Approximately 50% by weight of oxygenated compounds. Third step: Decarboxylation and/or hydrogenation (5 < P < 100 bar), preferably between 10 and 50 bar. Conversion to biokerosene: 70 - 80% hydrocarbons with carbon numbers between 9 and 16 (9<C<16).

Claims (1)

1. Biokerosene production process in an integrated route characterized by obtaining biokerosene (1) and biokerosene (2) and comprising the following steps: a) Preparation of the raw material carried out at atmospheric pressure containing materials rich in glycerides and at least one chain alcohol short from C1 to C5 and at least one homogeneous and/or heterogeneous catalyst; b) Promoting the transesterification reaction at atmospheric pressure and temperature between ambient and up to 150°C; c) Purification of the product obtained in reaction (b) by high vacuum comprising a pressure in the order of 0.001 to 5 mmHg or 1.33.10-6 to 10-2 bar obtaining biokerosene (1); d) Obtaining a residue consisting of heavy esters (C > 16) obtained from step (C); e) Decarbonylation carried out in fixed or fluidized bed reactors and in the presence of zeolites as catalysts at temperatures between 250 and 450°C; f) Obtaining a mixture of hydrocarbons and oxygenated compounds containing approximately 50% of each stream; g) Separation of the reaction product carried out in (f) by atmospheric distillation; h) Obtaining a fraction consisting of hydrocarbons compatible with the composition of kerosene of fossil origin; i) Reaction of decarboxylation and/or hydrogenation of the stream consisting of oxygenated compounds; and j) Purification of the reaction product (i) by distillation at atmospheric pressure, obtaining biokerosene (2) and hydrocarbons with smaller chains (C < 9).

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