WO2008083600A1

WO2008083600A1 - An integrated coal liquefaction process

Info

Publication number: WO2008083600A1
Application number: PCT/CN2007/071380
Authority: WO
Inventors: Rocco Fiato; Youqi Wang
Original assignee: Accelergy Shanghai R & D Center Co., Ltd.; Accelergy Corporation
Priority date: 2006-12-30
Filing date: 2007-12-29
Publication date: 2008-07-17
Also published as: CN101270294A; WO2008083600A8

Abstract

An integrated coal liquefaction process includes a coal gasification step (201), a Fischer-Tropsch synthesis step (203), a coal carbonylation step (207) and a coal direct liquefaction step (209), wherein the carbon monoxide consumption during water gas shift conversion reaction in the Fischer-Tropsch synthesis step (203) is less than 5%. The carbon monoxide in the synthesis gas produced from the coal gasification step (201) or t he carbon monoxide in the tail gas produced from the synthesis gas converting step (203) are used in the coal carbonylation step (207). The pretreated coal from the coal carbonylation step (207) is subjected to hydrogenation liquefaction in the coal direct liquefaction step (209). Applying recovered carbon monoxide to carbonylation reaction of feed coal can reduce the carbon dioxide emission of the liquefaction process, and simultaneously increase the utilization rate of carbon.

Description

Integrated coal liquefaction method

The present invention relates to an integrated coalification method.

Coal liquefaction is a clean coal technology that takes a solid state of coal through a series of chemical processing processes to convert it into a liquid product.

In general, there are four main ways of coal liquefaction: direct hydrogenation, donor sol vent h drogenation, indirect gasification (gasttlcatton) and Fischer-Tropsch synthesis (FT synthesis) Indirect Mquefaciion* tOlysis or thermal degradation (see Kirk Othoraer's {(Fuels))),

Direct hydrotreating (also known as direct coal liquefaction) is the process of dissolving coal in solid state at high temperatures (above 750 degrees Fahrenheit), high pressure (above 1 OMPa), hydrogen (or ^co + , ^{C() ÷} ). Under the action of 3⁄4, the molecules in the coal are hydrocracked and directly converted into the processing of liquid products. Indirect liquefaction is a process in which a gasification of a monolithic state is first obtained to obtain a synthesis gas ( ^{co +} ), and a synthesis gas is used as a raw material to synthesize a liquid product, wherein Fischer-Tropsch Synthesis is produced by using synthesis gas as a raw material. The most important method of coal liquefaction of dazzling products.

The industry has been hoping to improve the efficiency of converting coal into high-value chemical products such as liquid fuels. Converting coal into high-value chemical products usually involves coal gasification to obtain syngas, the main components of which are hydrogen and carbon monoxide. Can be used to produce a variety of chemical products, such as liquid fuel, methanol, acetic acid, dimethyl ether, oxygenated alcohol (o?io a) oohois), isocyanate, etc.

At present, there are two main methods for converting syngas into traditional fuels and lubricating oils. One is Fischer-Tropsch synthesis (referred to as Fischer-Tropsch synthesis); the other is to convert syngas into methanol, and then convert it to methanol. Highly aromatic gasoiiiie (the gas is called GTS process λ and natural gas can also be converted into syngas for the production of the above products, where syngas production is one of the most expensive steps. Yes. Produce a suitable syngas ratio of hydrogen to carbon monoxide to optimize subsequent product structure And to avoid problems in the production of syngas.

Coal gasification can be carried out using a commercial gasification unit to produce syngas, and a synthesis gas having a hydrogen to carbon ratio of 0.5:1 to 1:1 can be obtained.

The Fischer-Tropsch synthesis and GTS processes have their own advantages and disadvantages. The advantage of Fischer-Tropsch is that its products are rich in chain pit hydrocarbons, while products rich in chain pits have better fuel properties and lubricity. The disadvantage of Fischer-Tropsch synthesis is that the amount of carbon dioxide produced is large. The advantage of the GTS process is that the products are gasoline and liquefied petroleum gas rich in aromatics (such as propane and butane λ but produced by the GTS process). The obtained aromatic-rich gasoline is easier to form a dwene and other polymethyl aromatic hydrocarbon products with a high crystallization point (usually forming a solid at normal temperature). In addition, the production cost of the GTS process is relatively high. The synthesis is high and its products cannot be used as lubricants, diesel fuels and aircraft fuels. Moreover, the GTS process also produces carbon dioxide.

In the existing coal liquefaction scheme, the Fischer-Tropsch synthesized carbon monoxide-rich tail gas is generally used as a fuel, or the water gas shift reaction to produce hydrogen gas. Both of these ways generate a large amount of carbon dioxide. However, the carbon dioxide emission has a great environmental impact. Destructive effect

For the above reasons, it is necessary to calculate a coal liquefaction method, which has a high liquid product yield per unit quantity of coal and a low carbon dioxide emission.

The invention provides an integrated coal liquefaction method comprising the following steps:

a coal gasification step of gasifying the raw material to obtain a synthesis gas;

Syngas conversion step converts the synthesis gas obtained from the coal gasification step into a hydrocarbon product and produces off-gas;

a coal carbonylation step of carbonylating coal by carbon monoxide in carbon monoxide or carbon monoxide in the tail gas to obtain carbonized coal;

In the direct coal liquefaction step, the carbonized coal is subjected to hydroliquefaction treatment.

According to the integrated coal liquefaction process of the present invention, the syngas conversion step comprises Fischer-Tropsch synthesis.

According to the integrated coal liquefaction process of the present invention, the synthesis gas conversion step further includes a water gas shift reaction. Preferably, the water gas shift reaction consumes less than 5% of the carbon monoxide consumed by the synthesis gas conversion step.

The integrated coal liquefaction process according to the present invention further comprises separating and reforming the naphtha from the hydrocarbon product of the synthesis gas conversion step, preferably to obtain gasoline and hydrogen.

The integrated coal liquefaction process according to the present invention further comprises the step of using the obtained hydrogen for the direct coal liquefaction step. The integrated coal liquefaction process of the present invention, the step of generating the direct liquefaction of coal and coal-bearing crude oil residue, optionally ^^ said method further comprising recovering the residue and the residue was used as the feedstock gasification step _s

According to the integrated coal liquefaction method of the present invention, the step of digitizing the coal includes directly utilizing the tail gas to carry out the carbonylation treatment.

The integrated coal liquefaction process according to the present invention further comprises a synthesis gas separation step for preferentially separating the synthesis gas to obtain carbon monoxide and a high hydrogen to carbon ratio synthesis gas.

According to the integrated type coal liquefaction method of the present invention, the coal is subjected to a carbonylation treatment using carbon monoxide obtained from the synthesis gas separation step in the coal carbonylation step.

The integrated coal liquefaction process according to the present invention converts the high hydrogen carbon into a product and produces an exhaust gas in a synthesis gas conversion step.

According to the integrated coal liquefaction method of the present invention, the coal is directly subjected to carbonylation treatment in the coal condensing step or the coal slurry formed by the coal and the inert solution is subjected to carbonylation treatment.

According to the integrated coal liquefaction process of the present invention, the molar amount of nitrogen in the synthesis gas is less than 5%.

According to the integrated coal liquefaction method of the present invention, compared with the conventional coal liquefaction process, the integrated coal liquefaction method can reduce the integrated coal of the invention by 15%, 30%, and 50%. The liquefaction process therefore has a higher production of liquid products per unit quantity of coal and lower carbon dioxide emissions.

Process FIG _β integrated coal liquefaction process of the present invention, FIG 1 DETAILED DESCRIPTION

3⁄4 1 is a process flow diagram of the integrated coal liquefaction process 200. The turf liquefaction process 200 includes a coal gasification step 201, a Fischer-Tropsch synthesis step 203, a carbon monoxide recovery step 205, a coal carbonylation step 207, a coal direct liquefaction step 209, a naphtha separation step 21.1, and a naphtha reforming step. 213. The coal gasification step 201 gasifies the coal-containing raw material to obtain a synthesis gas Fischer-Tropsch synthesis step 203. The synthesis gas obtained in the coal gasification step 2 is subjected to Fischer-Tropsch synthesis to obtain a hydrocarbon product and a carbon monoxide-rich tail gas, which is obtained by the coal gasification step 201. The synthesis gas has a relatively low hydrogen carbon. The synthesis gas can also be separated by a carbon monoxide recovery step 205 to obtain a portion of the carbon monoxide in the synthesis gas and a high hydrogen to carbon ratio synthesis gas, and the high hydrogen to carbon synthesis gas is subjected to Fischer-Tropsch synthesis. Among them, the high hydrogen carbon has a higher hydrogen to carbon ratio than the hydrogen gas of the synthesis gas compared to the synthesis gas obtained in the coal gasification step 201. - The carbon oxide recovery step 205 is also available from Fischer-Tropsch The carbon monoxide is recovered in the tail gas of step 203. The coal carboxylation step 207 is carried out by carbonylation of carbon monoxide obtained by the carbon monoxide recovery step 205 with carbon to obtain a carbonized coal to improve the efficiency of subsequent direct coal liquefaction, wherein the carbonized coal refers to The carbonized carbon. The direct coal liquefaction step 209 directly liquefies the coal treated by the coal carbonylation step 207 to obtain a crude oil product and a residue, wherein the residue can be used as a raw material for the coal gasification step 201. Naphtha separation step 2 1) Separating naphtha and heavy shield product from the hydrocarbon product obtained in the Fischer-Tropsch synthesis step 203. The naphtha reforming step 213 reforms the naphtha obtained by the naphtha separation step 21 to obtain hydrogen gas. Gasoline, wherein helium can be used as a raw material for direct coal liquefaction step 209

Wherein, according to different raw materials, the one gasification carbon recovery step 205 may include different processing equipment, such as a gas separation device for separating carbon monoxide in the synthesis gas.

In one embodiment, syngas can also be used in the production of products such as methanol. _ Oxygen carbon can be, but is not limited to, recovered in the following manner, adsorption (eg, pressure swing adsorption, displacement purge cycles), low temperature separation (ciyogenk separation) ), membrane separation, etc. may require multiple recovery steps throughout the process to recover carbon monoxide or hydrogen in the syngas and off-gas, etc. Additionally, in the process of the present invention, in addition to utilizing recovered carbon monoxide> Source Supplementation Oxidation Reduction Because of the high cost of the membrane separation unit, it is recommended to use other separation units. In one embodiment, by partial oxidation to obtain gas, the process can obtain argon-rich gas without membrane separation. Since the main by-product of Fischer-Tropsch synthesis is water, the carbon monoxide-rich gas can be directly obtained by condensing the high molecular weight product in the Fischer-Tropsch synthesis product without membrane separation, so the Fischer-Tropsch synthesized tail gas can be directly used for coal. Carbonylation step

Catalysts and reaction conditions for the Fischer-Tropsch synthesis are known in the art, as disclosed in European Patent No. EP 0 921 184 A1.

The Fischer-Tropsch synthesis can be understood by stoichiometry. For example, the Fischer-Tropsch synthesis of syngas can generate Fischer-Tropsch products from three typical reactions, including pit hydrocarbons and olefins, which can be represented by the general formula, which is precisely The chemical composition of the monoolefin is expressed, but only a large chemical composition of at least 5 carbon atoms is expressed. Among them, the reaction conditions for determining η (the average silicon atom content of the product) include, but are not limited to, the following, such as temperature, pressure, space velocity, catalyst type, synthesis gas composition, and the like. The ideal synthesis gas has a hydrogen to carbon ratio of 2:1. In the low-water conversion rate of non-shifting FT synthesis, the carbon-gas conversion reaction consumes less carbon monoxide than the Fischer-Tropsch synthesis of carbon monoxide. 5% of the total amount, the following chemical formula is the chemical formula of Fischer-Tropsch synthesis, chemistry Formula 2 is the chemical formula of the water gas shift reaction.

Chemical formula 2H ₂ + CO→ -C3⁄4 - +H ₂ 0 Chemical formula 2: ^H fi CO→ Π + CO,

'Express a typical alkane from the Fischer-Tropsch synthesis. In general, the production of by-product water in the Fischer-Tropsch synthesis is very large. For example, the ratio of water to ^^ is about 56% and 44%, respectively.

The preferred embodiment of the present invention can reduce carbon dioxide emissions by 15%, or even 30%, or even 50%, compared to conventional Fischer-Tropsch synthesis.

While reducing the amount of dioxide emissions, the present invention can also increase the utilization of carbon. Valuable products of coal liquefaction include, but are not limited to, the following, transportation fuels include aircraft fuel, diesel, gasoline, aromatics, synthetic crude oil, Lubricating oil

One source of hydrogen used in the integrated coal liquefaction process of the present invention is hydrogen obtained by reforming naphtha. During the reforming of the naphtha, the c _{5 ÷} product is converted into an aromatic compound or a branched product and produced. hydrogen.

The aromatic compounds and branched products produced by naphtha reforming can be used for, but not limited to, the following octane-rich mixtures in gasoline, mainly including aromatic compounds, chemical benzene, especially for the production of rings. Hexylamine, ethylbenzene, isopropylbenzene, used to produce para-formaldehyde

Reducing the Fischer-Tropsch synthesis of hydrogen will lead to Fischer-Tropsch synthesis product c ₅ product hydrogen to carbon ratio decreases. That is to say, even if the gas to carbon ratio of the syngas is 2:1, as the partial product is converted into an aromatic compound, the hydroquinone ratio of the C ₅ product will be lower than 1, 95: even lower than 1, 9:1. , c _WQ products are converted to aromatic compounds, their hydrogen-carbon ratio is lower than the product of C _H >+

The hydroquinone ratio of the product can be detected by techniques known in the art, such as Carlo-Erba combustion and gas chromatography and magnetic resonance analysis, and the individual products are better analyzed separately."

The product obtained by the integrated coal liquefaction process of the present invention can form a mixture such as synthetic crude oil _: In addition, the product can also be separated, such as liquefied petroleum gas (product of QM), concentrate (product of C ₆ ) rich mixture oct appearance (the aromatic compound C _e), jet fuel, diesel fuel, other distillate fuels, lubricating oil mixture (kibe blend stocks), a mixture of raw lubricant obliquely (lube blend feedstocks) ₀ Hydrogen produced by naphtha reforming can also be used in other steps, such as hydrogenation of C ₅₄ products to remove olefins, gas makeup and other heteroatoms (heteroatom)

The steps in the integrated coal liquefaction process of the present invention may be carried out in parallel, with some of the steps being associated with other steps. For example, Fischer-Tropsch synthesized carbon monoxide-rich tail gas is used in the carbonylation reaction.

The Huanization reaction can be carried out under the action of a homogeneous catalyst. These catalysts can be compounds of the Vm group, such as cobalt, iron, nickel, ruthenium, osmium, platinum. It is recommended to use non-noble metals. The best catalyst of cobalt also contains a ligand. For example, halides, amines, brick hydrogen, substituted amines, substituted phosphines, and other known organic compounds are carbonylation reaction conditions of 1 to 1000 atmospheres, 25 to 400 degrees Celsius, and coal can react with carbon monoxide alone. It can be dissolved in an inert solvent to react with carbon monoxide.

On the one hand, the liquid product of the direct liquefaction of the carbonized coal is higher than that of the untreated coal.

On the other hand, since part of the carbon monoxide in the synthesis gas is consumed by the coal carbonylation step, the synthesis gas conversion step does not require a water gas shift reaction to obtain a hydrogen-carbon ratio to a suitable synthesis gas, and the carbon dioxide emission is lowered.

Claims

1 . An integrated coal liquefaction method comprising the steps of: a coal gasification step of gasifying a coal-containing raw material to obtain a synthesis gas; and a synthesis gas conversion step of converting the synthesis gas obtained by the coal gasification step into a hydrocarbon product And produce exhaust gas;

The coal carbonylation step, the carbonization of the coal by carbon monoxide in the synthesis gas or the carbon monoxide in the tail gas to obtain carbonized coal; the direct hydrogenation step of the coal, the hydrochlorination of the carbonized coal „ 2, such as The integrated coal liquefaction process of claim 1 wherein said syngas conversion step comprises Fischer-Tropsch synthesis

The integrated coal liquefaction method according to claim 1, wherein the gas conversion step further comprises a water gas shift reaction, wherein the water gas conversion reaction consumes less carbon monoxide than the synthesis gas conversion step. 5% of the carbon monoxide consumed. 4. The integrated coal liquefaction process of claim 2, further comprising separating and reforming the naphtha from the hydrocarbon product of the syngas conversion step to produce gasoline and hydrogen.

5. The integrated coal liquefaction process according to claim 4, further comprising the step of using the obtained hydrogen for the direct coal liquefaction step 6, the integrated coal liquefaction method according to claim 1, The method is characterized in that the direct coal liquefaction step produces crude oil and coal-containing residues, and the method further comprises recovering the residue and using the residue as a raw material for the coal gasification step.

7. The integrated coal liquefaction process according to the claims, wherein the coal carbonylation step comprises directly carbonylating the coal by using the tail gas. 8. The integrated type according to claim 1. The coal liquefaction method is characterized in that the method further comprises a synthesis gas separation step, and the synthesis gas is separated to obtain cerium oxide and high hydrogen to carbon synthesis gas.

9. The integrated coal liquefaction process according to claim 8, wherein the coal carbonylation step ― g―

Mercury reduction treatment using the oxidative reduction coal obtained from the synthesis gas separation step,

The integrated coal liquefaction process according to claim 8, wherein the high hydrogen carbon is converted into a product and a tail gas is produced in the synthesis gas conversion step. 1. The integrated coal desalination method according to the claims, characterized in that _s is directly subjected to carbonylation treatment of the coal in the post-coalization step or carbonization treatment of the coal slurry formed by the coal and the inert solution.