HK1177221B - Method for preparing fuel from bio-oil - Google Patents

Abstract

This invention provides a method for preparing fuel from bio-oil comprising: (a) performing a catalytic cracking deoxygenation of the bio-oil by using a cracking deoxygenation catalyst under heat; (b) mixing hydrogen and products of the step (a); and (c) performing a catalytic hydrodeoxygenation of the mixture of the step (b) by using a hydrodeoxygenation catalyst under heat. Accordingly, a bio-sourced clean fuel having components equivalent to the fuel rom refining crude oil is prepared

Description

Method for preparing fuel from biological grease

Technical Field

The invention relates to the technical field of energy, in particular to a method for preparing fuel from biological grease.

Background

The increasing shortage of fossil fuels and the environmental pollution caused by their combustion has forced the search for renewable clean fuels. In the alternative to petrochemical fuels, clean fuels produced from renewable biological greases (e.g., soybean oil, jatropha oil, lard, food waste oil) are considered green, renewable, carbon neutral technology routes.

Biological oils and fats such as vegetable oils and fats are fats extracted from seeds, pulp and other parts of plants, and contain a large amount of long-chain carbon triglycerides and free fatty acids. Biological oils and fats are classified into two major categories, edible and industrial, and those which are liquid at normal temperature are called oils, and those which are solid and semisolid are called fats. The biological grease and crude oil (including waste lubricating oil) have great difference in composition, and the most important difference is that the biological grease has high oxygen content and low contents of sulfur, nitrogen and aromatic hydrocarbon; crude oil, on the other hand, contains high amounts of sulfur, nitrogen and aromatics, and very low amounts of oxygen. Therefore, the method for producing a fuel from crude oil as a raw material cannot be applied to a processing method using a biological fat as a raw material, based on the difference in the composition components.

There are some industrial applications and technologies for preparing biomass fuel (e.g., biodiesel) from bio-oil to be applied industrially, and these technologies can be roughly classified into two types: transesterification techniques or direct hydrogenation techniques. There have been many research results and reports exploring the aforementioned technology.

Chinese patent publication No. CN101328418 teaches a method for producing biodiesel from vegetable oil, but this method requires the consumption of a large amount of ethanol to react with the vegetable oil to form grease. Chinese patent publication No. CN1858161A teaches a method for producing biodiesel from palm oil, which requires degumming, deacidification, dehydration, etc. of raw palm oil before the low-carbon alcohol esterification step. Chinese patent publication No. CN101230309A teaches that in the method for preparing biodiesel from palm oil with a reduced acid value, esterification must be performed twice, and methanol required in the esterification exchange is 6-9 times (molar ratio) of the oil, and methanol is not recycled, which is environmentally friendly and economical.

The prior art has the disadvantages of complicated process, high operation complexity and high energy consumption; and in the esterification exchange process, the high use amount of alcohols such as methanol or ethanol is involved, so that the production cost is greatly increased.

In addition, chinese patent publication No. CN101070483A teaches that the production of biodiesel from suaeda glauca seed oil requires a large amount of water for washing after the esterification exchange. Chinese patent publication No. CN1412278A teaches a method for producing biodiesel using high acid value grease, palm oil, with a strong acid as a catalyst, but using this method generates a large amount of waste water and severely corrodes the reactor. The prior art generates a large amount of wastewater, thereby not only improving the production cost, but also being not in line with the environmental protection purpose and the economic benefit.

As for the direct hydrogenation technology, WO2009/039347 teaches a technology for treating a bio-renewable feedstock (bionerewableeedstock) to produce a diesel fraction, in a two-step process of hydrodeoxygenation and hydroisomerization. US2006/0207166 teaches a technique of simultaneous hydrodeoxygenation and hydroisomerization. A common drawback of these techniques is the poor stability of the catalyst and the high hydrogen consumption of the process, which can cause problems especially for the processing of vegetable oils and animal fats with high oxygen content.

In particular, direct hydrogenation techniques are limited by the content of free fatty acids in the feedstock, and so far the literature of the prior art only discloses the direct hydrotreatment of up to 15% of free fatty acids to produce hydrocarbon fuels (yanyong liuet al, chem. lett.2009,38,552).

Generally speaking, in the technology commonly used for preparing diesel fuel from biological grease at present, the ester exchange technology is to produce the biodiesel from the biological grease through ester exchange, a large amount of low-carbon alcohol is consumed, and the production cost is increased. In the esterification, strong acid is used as a catalyst, so that the production equipment is seriously corroded, and a large amount of glycerin byproducts are generated at the same time, and subsequent separation is needed. Washing of the product after esterification generates a large amount of wastewater, and part of methods relate to multiple times of esterification exchange treatment and are complicated to operate. On the other hand, the direct hydrogenation technology is used for directly carrying out hydrodeoxygenation on animal and vegetable oil to produce diesel oil, and not only is the hydrogen consumption high, but also the catalyst is quickly deactivated. Because the raw oil contains 10-15% of oxygen, a large amount of reaction heat can be released by hydrogenation, and the problem that the reaction temperature is controlled without quickly inactivating a catalyst is difficult to solve; meanwhile, the consumption of hydrogen for processing raw oil is high, and a large amount of supplementary hydrogen and quenching hydrogen are needed in the process for keeping the hydrogen partial pressure stable.

Meanwhile, other technologies for preparing biodiesel from biological grease exist in the prior art, for example, US2006/0186020 discloses a method for co-refining vegetable oil and crude oil, wherein the content of the vegetable oil is between 1% and 75%, and the method does not use the vegetable oil alone. Chinese patent publication No. CN10101314748A discloses a catalytic conversion method of animal and vegetable fats, in which the product components are mainly C2-C4 olefins, and the total yield is only 45wt%, and the obtained gasoline and diesel oil components are too little, and no hydrorefining of gasoline and diesel oil is involved.

Chinese patent publication No. CN101475870A teaches hydrocarbon catalytic cracking distillation technology for spent lubricating oil resources composed mainly of hydrocarbons. In the technology, the treated waste lubricating oil mainly comprises alkanes, the catalytic cracking is to selectively break carbon-carbon bonds (C-C bonds), and the main reaction is as follows:

R₁-CH₂-CH₂-R₂→R₁-CH₃+CH₂＝R₂

the cleavage reaction does not form water (H)₂O) and thus does not need to consider the water resistance of the catalyst. The waste lubricating oil mainly comprises alkane, and the alkane and the alkene are directly formed after catalytic cracking. However, as described above, the composition of the bio-oil is greatly different from that of the crude oil (including the waste lubricating oil), the main component of the bio-oil has a high oxygen content, and the cracking must be performed in consideration of the breaking of carbon-oxygen bond, the generation of water, and the likeFactors, therefore, vary greatly in the mechanism of catalysis, and the hydrothermal stability of the catalyst must be considered. Therefore, the technique taught by chinese patent publication No. CN101475870A is not suitable for processing of biological oils and fats.

In summary, although there are many routes and research results for processing and manufacturing biodiesel from bio-based oils and fats, biodiesel is not considered to be an ideal diesel blending component because the obtained biodiesel has high density, cannot be blended with petroleum diesel components in a large proportion, has low calorific value, and is not economical for fuels blended with petroleum diesel components.

Disclosure of Invention

In order to overcome the problems, the invention provides a novel biological grease processing technology, which can produce high-quality biomass fuel and is extremely suitable for being used as a diesel oil blending component.

Specifically, the invention provides a method for preparing biomass fuel, which takes biological grease as raw material and produces the biomass fuel with fuel components equivalent to those obtained by refining crude oil through the following steps: (a) carrying out catalytic cracking deoxidation reaction on the biological grease in the presence of a cracking deoxidation catalyst and under the heating condition; (b) mixing the product of step (a) with hydrogen; and (c) subjecting the mixture from step (b) to a catalytic hydrodeoxygenation reaction in the presence of a hydrodeoxygenation catalyst under heated conditions. The product obtained in step (c) may be further fractionated according to practical requirements. It is generally considered that hydrogen is mixed with the catalytic cracking deoxygenation product before being injected into the reaction tower to perform the reaction of step (c), but hydrogen may be directly injected into the reaction tower for hydrogenation and then mixed with the catalytic cracking deoxygenation product to perform the reaction of step (c).

The method is technically characterized in that a dual deoxidation step of catalytic cracking deoxidation and catalytic hydrodeoxygenation is used, so that the defects of large heat release and rapid catalyst inactivation caused by the use of a direct hydrogenation technology in the prior art can be avoided, and the hydrogen consumption is greatly reduced. In addition, the method of the invention which flexibly combines catalytic cracking deoxidation and catalytic hydrogenation deoxidation can not only be operated continuously, but also be operated separately. The waste slag and the waste gas generated are comprehensively utilized for heating, so that the whole production process is more energy-saving and environment-friendly.

Drawings

FIG. 1 depicts one embodiment of the method of the present invention.

Description of the main component symbols:

1 distillation still 6 heating furnace

2 catalytic distillation tower 7 hydrofining reaction tower

3 condenser 8 hydrogen booster

4 vapor-liquid separator 9 atmospheric distillation tower

5 liquid feed pump

Detailed Description

The following further describes an embodiment of the present invention with reference to the drawings.

The biological oil and fat of the present invention may be animal, plant, microbial or their mixture. Industrial or edible biological oils and fats can be used. In general, biological oils are rich in triglycerides and free fatty acids, with the chain length of fatty acids usually being C12-C24, more often than C16 and C18. Examples of biological oils include, by way of example and not limitation, rapeseed oil, soybean oil, palm oil, sunflower oil, cottonseed oil, jatropha oil, olive oil, castor oil, microalgal oil, tallow, lard, butter, poultry fat, fish oil, restaurant waste oil, and the like. In one embodiment, vegetable fats are the preferred raw material.

The fuel that can be produced by the present invention is generally referred to as biomass fuel, and means a solid, liquid, or gas composed of or extracted from biomass, and the so-called biomass means an organic living body or a product of metabolism of the organic living body. In a preferred embodiment, the biodiesel has a composition comparable to petroleum diesel obtained by refining petrochemical feedstocks (e.g., crude oil), has a high compatibility, is well-blended, and has properties and applications comparable to petroleum diesel.

The invention adopts a double deoxidation process of catalytic cracking deoxidation and catalytic hydrodeoxygenation. The method comprises the steps of firstly, treating the biological grease by adopting a technology combining catalytic cracking and distillation, removing partial oxygen elements in raw materials in the process, and then removing the residual oxygen elements through catalytic hydrogenation reaction. Because hydrogen is not needed in the step of catalytic cracking deoxidation and most of oxygen elements are removed, the consumption of hydrogen in the subsequent catalytic hydrodeoxygenation step can be greatly reduced.

In the catalytic cracking deoxidation step, partial oxygen is removed from free fatty acid through decarbonylation, or decarboxylation is carried out to generate CO and H₂O and olefins, while triglycerides are decarbonylated by cracking. Decarboxylation to generate corresponding long-chain alkane, alkene and CO₂、CO、H₂O, and propylene or propane. The chemical reaction formula is shown as follows:

R-CH₂-COOH→R-CH₃+CO₂or R ═ CH₂+CO+H₂O

This step also causes reactions such as C-C bond cleavage, which are not related to the cleavage deoxidation, to occur.

The selected pyrolysis deoxygenation catalyst needs to have strong water resistance due to the formation of water in this step. In addition, the biological grease catalytic cracking reaction usually has C-C fracture and C-O fracture, and for this reason, the catalyst can be modulated to ensure that the selective fracture, namely the C-O bond fracture occurs, but the C-C is not fractured. Since the fraction after selective cleavage of the carbon-oxygen bond usually still contains the oxygen element, a further deoxygenation step is carried out.

Under the condition of catalytic hydrodeoxygenation, triglyceride generates normal alkane after hydrogenation saturation, hydrogenation decarboxylation, hydrogenation decarbonylation and hydrogenation deoxygenation reactions. The chemical reactions that occur are as follows:

R-CH＝CH₂+H₂→R-CH₂-CH₃

R-COOH+H₂→R-CH₃+H₂o or R-H + CO₂

R in all the chemical reaction equations is C10-C22 alkyl. There are also side reactions, mainly hydrogenolysis of C-C bonds, which produce smaller hydrocarbon molecules.

Through the hydrodeoxygenation reaction, oxygen-containing fractions which are not removed in the catalytic cracking and deoxygenation process are further removed, and simultaneously, olefins generated in the catalytic cracking process are saturated, so that a product with high stability is obtained.

The invention has the advantages that the fraction deoxidized by catalytic cracking is subjected to hydrodeoxygenation reaction, the reaction conditions are mild (the hydrogen partial pressure is low, the reaction temperature is low), the catalyst stability is good, the hydrogen consumption is low, and the existing equipment of an oil refinery can be utilized to the maximum extent for production.

The biomass fuel produced according to the process of the invention can be used directly as a fuel, for example as gasoline, diesel, aviation kerosene or the like, or to blend components. The biomass fuel contains main carbon chain components of C8-C24, has a higher cetane number than traditional petroleum diesel oil, has a lower density, and is substantially free of sulfur, nitrogen and aromatic hydrocarbons. Based on the characteristics, the clean fuel produced by the method is an ideal high-quality diesel blending component, and can be blended with low-value catalytic light cycle oil hydrotreating generated oil (with lower cetane number), so that the ultra-low sulfur diesel meeting the relevant standard requirements is produced.

The invention is mainly based on two steps of catalytic cracking deoxidation and catalytic hydrogenation deoxidation, the combination of the two steps is very flexible, and the invention not only can be operated continuously, but also can be operated separately. Specifically, the first reaction zone in which catalytic cracking deoxidation occurs and the second reaction zone in which catalytic hydrodeoxygenation occurs may be operated continuously or intermittently, respectively, depending on the actual operating conditions.

The hydrodeoxygenation step in the second reaction zone is preferably operated continuously, in terms of industrial application, with the advantage of stable reaction conditions and stable products; the catalytic cracking deoxygenation step in the first reaction zone may be operated in a batch mode. However, if the continuous operation of the hydrodeoxygenation step is satisfied, the catalytic cracking deoxygenation step may be performed by a multi-pot circulation operation or may be performed by a continuous catalytic distillation operation.

The pyrolysis deoxygenation catalyst used in the first reaction zone is, for example and without limitation, a molecular sieve catalyst. Other suitable cracking deoxygenation catalysts can be found in the handbook of Industrial catalysts (published by chemical industry publishers, 2004, written by Huang Zhongtao, which is incorporated herein by reference). In one embodiment, a mixture of alumina and molecular sieve is used as the cracking catalyst. The molecular sieve may be selected from HY, Hbeta, SAPO-31, HZSM-5, HZSM-22, or a mixture of any combination of the foregoing, and may be present in an amount of about 5-70 wt%. After mixing the alumina and the molecular sieve, a binder (such as sesbania powder) can be added for extrusion molding. The size of the shaped pyrolysis deoxygenation catalyst is determined by the actual conditions of the first reaction zone, e.g., by the diameter of the catalytic distillation column. In one embodiment, the diameter ratio of the equivalent diameter of the shaped pyrolysis deoxygenation catalyst to the catalytic distillation column should be less than 0.1.

The ratio of the pyrolysis deoxygenation catalyst to the feedstock introduced into the first reaction zone may be determined depending on the actual operating conditions, and the ratio is not particularly limited. In one embodiment, the mass ratio of the cracking deoxygenation catalyst to the bio-oil may be about 1:5 to 1:50, i.e., may be 1: 5. 1: 10. 1: 15. 1: 20. 1: 30. 1: 40. 1:50, etc. In one embodiment, the mass ratio of the cracking deoxidation catalyst to the biological grease is 1:20 is preferred. In another embodiment, the mass ratio of the cracking deoxygenation catalyst to the biological grease is 1:10 is preferred.

In an embodiment, the catalytic action of the first reaction zone may be performed in a heated environment of about 100 to 600 ℃ to obtain the deoxygenated products of cracking such as olefins, alkanes, carbon monoxide, carbon dioxide, water, etc. In one embodiment, the pyrolysis deoxygenation catalysis may be performed at a temperature within a range defined by a temperature of about 100 ℃, 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, 600 ℃, or any two thereof, wherein the composition of the feedstock affects the selection of the temperature, and the temperature of the pyrolysis deoxygenation reaction is generally determined according to the flow of the feedstock. In one embodiment, about 300 ℃ and 600 ℃ are preferred.

The product from the first reaction zone is thoroughly mixed with hydrogen and then introduced into a second reaction zone containing a hydrodeoxygenation catalyst for catalytic hydrodeoxygenation.

The hydrodeoxygenation catalyst used in the second reaction zone is, for example and without limitation, a supported metal catalyst. Other suitable hydrodeoxygenation catalysts can be found in the handbook of Industrial catalysts (eds. Huang, chemical industry Press, 2004) and hydrofinishing (eds. King of Ching, China petrochemical Press, 2008) (incorporated herein by reference)The means of filing both are incorporated into the specification of the present application). In one embodiment, the supported metal catalyst is composed of a carrier and a metal distributed on the carrier, and the metal can be a single metal, a mixture of multiple metals, or an alloy. The metal may be selected from transition metals of the periodic table of elements, including metallic elements of groups IIIB, IVB, VB, VIB, VIIB, VIII. In one embodiment, group VIII is preferred and may be selected from Fe, Co, Ni, Ru, RH, Pd, Os, Ir, Pt, etc. In another embodiment, the metal can be selected from Ni, Co, Mo, W, Cu, Pd, Ru, Pt, etc. The metal content may be from 0.1 to 30 wt%. The support may be selected from an oxide support having a dual mesoporous composite structure or a carbon material. In one embodiment, the oxide support may be selected from SiO₂、Al₂O₃、TiO₂、SiO₂-Al₂O₃、Al₂O₃-TiO₂Or SiO₂-Al₂O₃-TiO₂。

The ratio of the hydrodeoxygenation catalyst to the reactants passed into the second reaction zone may be determined according to the actual operating conditions and need not be particularly limited.

In one embodiment, the catalytic hydrodeoxygenation in the second reaction zone can be performed in a heated environment of about 200 to 400 ℃, for example, about 200 ℃, 250 ℃, 300 ℃, 350 ℃, 400 ℃, or within a temperature range defined by any of the foregoing. In one embodiment, about 300 ℃ to about 400 ℃ is preferred.

Aiming at the temperature conditions, an operation system can be integrated, and waste gas and waste residue generated by the method are used for heating, so that the energy consumption can be reduced, no secondary pollution is caused, and the effects of energy conservation and environmental protection are achieved.

In one embodiment, the vegetable oil is injected into a distillation still for heating and gasification, and then catalytic cracking deoxidation reaction is performed in a catalytic distillation tower, the temperature of the distillation still is controlled to be between 100 ℃ and 600 ℃, an alumina-molecular sieve mixture is used as a cracking deoxidation catalyst, and the ratio of the catalyst to the oil is controlled to be 1:5-1:20, respectively. The above reaction steps may be repeatedThe operation may be carried out intermittently or continuously by switching the distillation still. And then, mixing the distilled fraction with hydrogen through a feed pump, and then introducing the mixture into a reaction tower provided with a hydrodeoxygenation catalyst for reaction, wherein the supported metal or sulfide is used as the hydrodeoxygenation catalyst. The feeding temperature of the reaction tower for hydrodeoxygenation is controlled at 200-400 ℃, the hydrogen partial pressure is 1-6MPa, and the volume space velocity is 0.5-4.0h^-1And the hydrogen-oil volume ratio is 200-: 1. finally, clean fuel derived from vegetable oil can be obtained, and the fuel is divided into gasoline and diesel according to the fraction temperature. In the invention, dry gas and waste residue generated in the process of converting the vegetable oil can be utilized for auxiliary heating.

The biomass fuel produced according to the process of the present invention, such as renewable diesel (renewablediesel), can be further processed as desired, isomerized to reduce the freezing point, and produce a fuel with good low temperature properties.

The following examples are provided to illustrate the present invention in detail, with the understanding that the examples are illustrative and not intended to limit the invention.

Example 1

The palmitic acid oil is used as the raw material of the method.

The basic properties, composition analysis and distillation range of the palmitic acid oil are shown in Table 1. The palmitoylated oil is solid at room temperature, has a free fatty acid content of up to 67%, and cannot be processed using prior art direct hydroprocessing techniques due to the too high fatty acid content (as mentioned above, the prior art teaches only direct hydroprocessing up to 15% of free fatty acids to produce hydrocarbon fuels). However, the present process may be used to process palmitic acid oils.

TABLE 1 basic characteristics of the palmitic oils

Injecting the palmitic acid oil into a distillation kettle, heating and gasifying the palmitic acid oil, and then carrying out catalytic cracking deoxidation reaction in a catalytic distillation tower, wherein the temperature of the distillation kettle is controlled to be between 100 ℃ and 600 ℃, an alumina-molecular sieve mixture is used as a cracking deoxidation catalyst, and the catalyst-oil ratio is controlled to be between 1 and 20. The gasoline and diesel fractions were separated according to the fraction temperature (< 360 ℃), and the results are shown in table 2.

TABLE 2 cracked deoxygenated product distribution

As can be seen from the comparison of tables 1 and 2, the catalytic cracking deoxidation step of the method of the invention can remove the oxygen content in the raw oil in the form of water, thereby reducing the generation of water in the subsequent hydrogenation process and prolonging the service life of the hydrogenation catalyst. Meanwhile, the yield of the gasoline and diesel oil fraction is about 80 percent.

And then, mixing the gasoline and diesel oil fractions obtained by catalytic cracking and deoxidation with hydrogen, and introducing the mixture into a reaction tower provided with a hydrodeoxygenation catalyst for reaction. The supported metal or metal sulfide is used as the hydrodeoxygenation catalyst. The remaining reaction conditions are shown in table 3, and the composition analysis of the resulting clean fuel is shown in table 4.

TABLE 3 hydrodeoxygenation conditions

Partial pressure of hydrogen	MPa	5.0
			Volume airspeed	h-1	1
Volume ratio of hydrogen to oil		800
			Reaction temperature	℃	310
Yield of liquid	%	97

TABLE 4 composition analysis of clean fuels

Appearance of the product	Colorless and transparent
		Freezing point of	-3
Hydrogen sulfide mg/kg	5.74
		Acidity of mgKOH/g	0.06
Density (20 ℃ C.) kg/m3	763.0
		Cetane index	64
Distillation range
		Initial boiling point of DEG C	66.8
50% recovery temperature	215.2
		90% recovery temperature	258.1
95% recovery temperature	267.5
		Final point of distillation (C)	273.7

As shown in Table 4, the acid value of the fraction obtained by catalytic cracking and deoxygenation of the palmitic acid oil was 0.06mgKOH/g, which is much lower than the standard value of the China biodiesel Standard (hereinafter referred to as BD 100). The sulfur content is lower than the standard value of China diesel oil (III) standard GB19147-2009 (hereinafter called national III diesel oil) and European Union (V) standard EN590:2004 (hereinafter called Euro V diesel oil). The cetane number is far higher than the standard values of national III diesel oil and European V diesel oil. The clean fuel derived from the palmitic acid oil according to the process of the present invention is indeed an excellent diesel fuel blending component.

Example 2

The jatropha curcas oil is used as the raw material of the method. The jatropha oil is liquid at room temperature, and the basic properties, the component analysis and the distillation range of the jatropha oil are shown in table 5.

TABLE 5 basic characteristics of Jatropha oil

Appearance of the product	Yellow transparent
		Water% (m/m)	<0.05
Density 15.6 deg.C g/cm3	0.9193
		Sulfur content mg/kg	<50
Content of free fatty acid%	1.9
		Content of fat%	99.6
Iodine value gI2/100g	103
		Distillation range
Initial boiling point of DEG C	405.6
		50% recovery temperature	573.9
90% recovery temperature	591.7
		95% recovery temperature	593.3
Final point of distillation (C)	603.5

The barbadosnut oil is injected into a distillation kettle for heating and gasification, and then catalytic cracking deoxidation reaction is carried out in a catalytic distillation tower, the temperature of the distillation kettle is controlled to be between 100 ℃ and 600 ℃, an alumina-molecular sieve mixture is used as a cracking deoxidation catalyst, and the agent-oil ratio is controlled to be between 1 and 20. The gasoline and diesel fractions were separated according to the fraction temperature (< 360 ℃), and the results are shown in table 6.

TABLE 6 deoxidation products from cracking distribution

As can be seen from the comparison of tables 5 and 6, the catalytic cracking deoxidation step of the method of the invention can remove the oxygen content in the raw oil in the form of water, thereby reducing the generation of water in the subsequent hydrogenation process and prolonging the service life of the hydrogenation catalyst. Meanwhile, the yield of the gasoline and diesel oil fraction is about 78 percent.

And then, mixing the gasoline and diesel oil fractions obtained by catalytic cracking and deoxidation with hydrogen, and introducing the mixture into a reaction tower provided with a hydrodeoxygenation catalyst for reaction. The supported metal or metal sulfide is used as the hydrodeoxygenation catalyst. The remaining reaction conditions are shown in Table 7, and the compositional analysis of the resulting clean fuel is shown in Table 8.

TABLE 7 hydrodeoxygenation conditions

Partial pressure of hydrogen	MPa	5.0
			Volume airspeed	h-1	1
Volume ratio of hydrogen to oil		800
			Reaction temperature	℃	310
Yield of liquid	%	98

TABLE 8 composition analysis of clean fuels

Appearance of the product	Colorless and transparent
		Freezing point of	-15
Hydrogen sulfide mg/kg	7.7
		Acidity of mgKOH/g	0.04
Density (20 ℃ C.) kg/m3	783.7
		Cetane index	43.4
Distillation range
		Initial boiling point of DEG C	101.2
50% recovery temperature	250.1
		90% recovery temperature	323.9
95% recovery temperature	350.2
		Final point of distillation (C)	372.6

As shown in table 8, the acid value of the fraction obtained from jatropha curcas oil was much lower than the standard value for BD 100; the sulfur content is also lower than the standard value of national III and European V diesel; and the cetane number accords with the national III diesel standard value.

Examples 1 and 2 provide the most difficult and easy to process, respectively, of inedible animal and vegetable fats and oils, and clean fuels having excellent properties can be obtained by the method of the present invention. The method is not particularly limited to the raw material of the biological grease, and can be applied to all biological greases, even the palmitic acid oil which is the most difficult to process, and can also produce high-quality clean fuel by the method.

The clean fuel produced by the process of the present invention has a major carbon chain composition of C8-C24, has a cetane number higher than that of conventional petroleum diesel, has a relatively low density, and is substantially free of sulfur, nitrogen, and aromatic hydrocarbons. Based on the characteristics, the clean fuel produced by the method is an ideal high-quality diesel blending component, and can be blended with low-value catalytic light cycle oil hydrotreating generated oil (with lower cetane number), so that the ultra-low sulfur diesel meeting the relevant standard requirements is produced.

Example 3

An example of the application of the process of the invention to the industrial level production of clean fuels is provided.

Referring to fig. 1, a biological fat raw material is injected into a distillation still 1, heated, and introduced into a catalytic distillation column 2, and a cracking deoxidation catalyst is disposed in the catalytic distillation column 2, and the cracking deoxidation is performed on the biological fat under a certain temperature condition. The gasoline and diesel oil fraction obtained from the catalytic distillation column 2 is introduced into a hydrorefining reaction column 7. Wherein, the gasoline and diesel oil fraction produced by the catalytic distillation tower 2 can be mixed with hydrogen gas through a feed pump 5, and then heated by a heat exchanger and a heating furnace 6 to enter a hydrofining reaction tower 7.

The hydrogenation refining reaction tower 7 is provided with a hydrogenation deoxidation catalyst, under the condition of a preset temperature, the fraction which is introduced into the hydrogenation refining reaction tower 7 from the catalytic distillation tower 2 and hydrogen gas are subjected to catalytic hydrogenation deoxidation, and finally the obtained product can be introduced into the atmospheric distillation tower 9 for fractionation to obtain clean fuels such as gasoline, diesel oil and the like.

The method provided by the invention comprises the steps of breaking a large number of carbon-oxygen bonds contained in the biological grease by catalytic cracking deoxidation treatment, and then carrying out catalytic hydrodeoxygenation to obtain the final clean fuel, so that the hydrogen consumption required by the hydrogenation reaction is effectively reduced. Compared with the prior art which adopts two-stage treatment of directly carrying out hydrodeoxygenation on the biological grease and then carrying out hydroisomerization or the prior art which combines hydrodeoxygenation and hydroisomerization into one-stage treatment, the method can save the hydrogen consumption by 50 percent. Compared with the ester exchange technology in the prior art, the method of the invention does not need low carbon alcohol and does not generate glycerin as a byproduct, and the method is simple and can greatly reduce the cost.

The foregoing description of the preferred embodiments of the present invention is intended to be illustrative, and not restrictive. The scope of the invention is subject to the scope of the claims. One of ordinary skill in the art, upon reading this description, would be able to effect appropriate modifications or alterations that would come within the scope of this invention.

Claims (22)

1. A method of making a fuel using a bio-grease, comprising:

(a) introducing the heated biological oil into a catalytic distillation tower equipped with a cracking deoxidation catalyst, and carrying out catalytic cracking deoxidation reaction on the biological oil under the heating condition;

(b) mixing the product of step (a) with hydrogen; and

(c) subjecting the mixture from step (b) to a catalytic hydrodeoxygenation reaction in the presence of a hydrodeoxygenation catalyst and under heated conditions.

2. The process of claim 1, wherein step (a) can be operated continuously or batch-wise.

3. The process of claim 1 wherein step (a) is operated using a multiple still cycle or a continuous catalytic distillation and step (c) is operated continuously.

4. The method of claim 1, wherein the biolipid is of animal origin, vegetable origin, microbial origin, or mixtures of the foregoing.

5. The method of claim 1, wherein the pyrolysis deoxygenation catalyst is selected from alumina, molecular sieves, or mixtures thereof.

6. The method of claim 5, wherein the molecular sieve is selected from one or more of the group consisting of HY, H β, SAPO-31, HZSM-5, HZSM-22.

7. The process of claim 5 wherein the pyrolysis deoxygenation catalyst is a mixture of alumina and molecular sieve, the molecular sieve content being from 5 to 70 wt%.

8. The process of claim 1 wherein the pyrolysis deoxygenation catalyst is shaped such that the ratio of its equivalent diameter to the diameter of the catalytic distillation column is less than 0.1.

9. The method of claim 1, wherein the mass ratio of the pyrolysis deoxygenation catalyst in step (a) to the reactants of this step is selected from the group consisting of 1:5, 1:10, 1:15, 1:20, 1:30, 1:40, 1: 50.

10. The method of claim 1, wherein the pyrolysis deoxygenation catalyst has water resistance.

11. The process of claim 1, wherein the heating conditions of step (a) are from 100 to 600 ℃.

12. The process of claim 1, wherein the product of step (a) comprises an alkene, an alkane, carbon monoxide, carbon dioxide, water, or a combination of the foregoing.

13. The method of claim 1, wherein step (a) comprises the following reaction:

wherein R is C_10-22An alkyl group.

14. The process of claim 1, wherein the hydrodeoxygenation catalyst comprises a supported metal catalyst and the metal is selected from one or more of the group consisting of group IIIB through group VIII metal elements and alloys thereof.

15. The process of claim 1, wherein the heating conditions of step (c) are from 200 to 400 ℃.

16. The method of claim 1, wherein step (c) comprises the following reaction:

wherein R is C_10-22An alkyl group.

17. The method of claim 1, further comprising:

(d) fractionating the product of step (c) to obtain gasoline and diesel.

18. The method of claim 1, wherein dry gas produced by the method is used for the supplemental heating of steps (a) and (c).

19. The process of claim 1 wherein the product of step (a) is mixed with hydrogen in step (b) after passing through a feed pump and then through a heat exchanger into a reaction column for hydrofinishing, and step (c) is carried out in the reaction column.

20. The process of claim 1 wherein step (a) further comprises a distillation operation.

21. The method as claimed in claim 1, wherein the bio-grease is heated by using a distillation still with a heating condition of 100-600 ℃, the cracking deoxygenation catalyst is an alumina-molecular sieve mixture, and the mass ratio of the cracking deoxygenation catalyst to the reactant of step (a) is 1:5-1: 20.

22. The process as claimed in claim 1, wherein the step (c) is carried out in a reaction column for hydrorefining, the hydrodeoxygenation catalyst is a supported metal catalyst, and the heating conditions in the reaction column are 200 ℃ to 400 ℃, the hydrogen partial pressure is 1 to 6MPa, and the volume space velocity is 0.5 to 4.0h^－1And a hydrogen to oil volume ratio of 200-.