CN118834705A - Flexible gasification method of Fischer-Tropsch synthesis reaction filter residues in gasification furnace - Google Patents

Abstract

The invention provides a flexible gasification method of filter residues in a gasifier for Fischer-Tropsch synthesis reaction, wherein the filter residues are subjected to hydrocarbon cracking reaction in the gasifier and coupled with water gas shift reaction of crude synthesis gas, so that the content of synthesis gas in the outlet gas of the gasifier can be increased, the hydrogen-carbon ratio can be regulated, the content of methane in the outlet gas of the gasifier can be increased, heat can be provided for the gasification process by heat release of the water gas shift reaction, the overall thermal efficiency of the gasifier is improved, and gasified residues can be discharged together with gasification slag.

Description

A flexible gasification method for Fischer-Tropsch synthesis reaction residue in a gasifier

Technical Field

The present invention belongs to the field of Fischer-Tropsch synthesis by-product processing, and specifically relates to a flexible gasification method for Fischer-Tropsch synthesis reaction residue in a gasifier, thereby increasing the synthesis gas content in the gasifier outlet gas, adjusting the hydrogen-carbon ratio, and increasing the methane content.

Background Art

Coal indirect liquefaction technology is an important development direction in the current coal chemical industry. The oil products synthesized by it have the advantages of being clean and environmentally friendly, and can replace current fossil fuels, which is of great significance to ensuring my country's energy security. Among them, coal gasification technology and Fischer-Tropsch synthesis reaction are important links in coal indirect liquefaction technology. Coal gasification technology uses coal as raw material and undergoes gasification reaction under the action of gasifying agent (oxygen + water vapor). Currently, fixed bed gasification technology and fluidized bed gasification technology are more widely used. Fixed bed gasification technology generally uses lump coal as raw material. Coal is added from the top of the gasifier and the gasifying agent is added from the bottom of the gasifier. The two are in countercurrent contact to undergo gasification reaction. The gasified slag is discharged from the bottom of the furnace. Representative ones are crushed coal pressurized gasifier gasification technology (Lurge furnace), crushed coal pressurized slag gasification technology (BGL furnace) and fixed bed interstitial gasification technology (UGI). Entrained-bed gasification technology uses powdered coal as raw material. Under the action of the gasifying agent and the crude synthesis gas produced in the furnace, the powdered coal maintains continuous and disordered boiling and suspended movement to undergo a gasification reaction. Representative technologies include SHELL dry coal powder pressurized gasification technology, GSP pulverized coal pressurized gasification technology and Texaco water-coal slurry pressurized gasification technology.

The Fischer-Tropsch synthesis reaction is a complex reaction that uses synthesis gas (hydrogen and carbon monoxide) as raw materials and mainly generates hydrocarbon products under the action of a catalyst. The filter residue produced by the Fischer-Tropsch synthesis reaction still contains a high content of hydrocarbons, but the prior art does not further utilize the hydrocarbons contained in the filter residue. The current Fischer-Tropsch synthesis process mainly uses an iron-based catalyst in a slurry bed reactor. During the reaction, the catalyst needs to be replaced regularly to ensure the reaction activity. During the replacement of the catalyst, a large amount of heavy wax will be discharged from the reactor with the waste catalyst. A filter is used to filter and separate the mixture of the heavy wax and the waste catalyst discharged above, and the clear liquid is used as the product, and the filter residue is used as a solid waste. Moreover, the heavy wax generated by the Fischer-Tropsch reaction is initially filtered through a filter inside the reactor, and then finely filtered by a filter with a filter aid added, and its filter residue is also used as a solid waste. In addition, the gas at the top outlet of the Fischer-Tropsch reactor contains a large amount of heavy hydrocarbons, which are initially cooled and separated to form heavy oil, and then finely filtered by a filter with a filter aid added, and its filter residue is also used as a solid waste. The hydrocarbon content in the above three kinds of filter residues is still as high as 35% to 60%. The existing technology mainly treats the filter residues by incineration, landfilling, etc., which not only pollutes the environment but also wastes resources. Although CN110607193A, CN110387261A, CN111991905A, etc. teach the use of extractants to treat Fischer-Tropsch residue wax, in actual applications, the extraction efficiency itself is not high, and the subsequent treatment of the extractant is also cumbersome and has no industrial applicability.

Therefore, the efficient utilization of Fischer-Tropsch synthesis reaction residue in industrial production still deserves further research in order to achieve higher economic efficiency of the Fischer-Tropsch synthesis reaction.

Summary of the invention

The object of the present invention is to provide a method for using Fischer-Tropsch synthesis reaction filter residue as a gasification raw material for flexible gasification in a gasifier to increase the content of synthesis gas in the gasifier outlet gas and adjust the hydrogen-carbon ratio and increase the methane content in the gasifier outlet gas. Thus, the solid waste filter residue can be effectively treated, the hydrocarbons therein can be fully recovered, and low-carbon oil and gas components can be produced as by-products. The hydrogen-carbon ratio of the gasifier outlet gas can be adjusted by coupling with the water-gas shift reaction, and the heat released by the water-gas shift reaction can provide heat for the gasification process, thereby improving the overall thermal efficiency of the gasifier, and the gasified residue can also be discharged together with the gasification furnace slag.

The present invention relates to a flexible gasification method for Fischer-Tropsch synthesis reaction residue in a gasifier, comprising the following steps:

(1) adding a carbon-containing raw material and a Fischer-Tropsch synthesis reaction residue into a gasifier, wherein hydrocarbons in the Fischer-Tropsch synthesis reaction residue undergo a cracking reaction in the gasifier to produce low-carbon oil and gas components and/or methane, and a metal catalyst in the Fischer-Tropsch synthesis reaction residue is oxidized to form an oxidized metal catalyst, and the carbon-containing raw material is gasified to produce a crude synthesis gas;

(2) a portion of the low-carbon oil and gas components and/or methane is oxidized into carbon oxides;

(3) the crude synthesis gas undergoes a water-gas shift reaction under the catalytic action of the oxidized metal catalyst;

(4) The filter aid, oxidized metal catalyst and slag in the Fischer-Tropsch synthesis reaction filter residue are discharged from the gasifier together.

The exemplary embodiments of the present invention can achieve the following beneficial effects and other advantages or benefits:

(1) The hydrocarbons in the Fischer-Tropsch synthesis reaction residue are fully recovered by using the Fischer-Tropsch synthesis reaction residue in the gasification unit of the coal indirect liquefaction process;

(2) The Fischer-Tropsch synthesis catalyst (especially the iron-based catalyst) in the Fischer-Tropsch synthesis reaction residue enters the gasifier and becomes an oxidized catalyst, which catalyzes the water-gas shift reaction to adjust the hydrogen-to-carbon ratio of the gas at the outlet of the gasifier;

(3) low-carbon oil and gas components such as methane are obtained by hydrocarbon cracking reaction in the gasifier, thereby increasing the methane content in the gas at the outlet of the gasifier;

(4) The gasification residue can also be discharged together with the gasification furnace slag.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are a part of the specification and together with the detailed description, they provide further explanation of the present invention but are not intended to limit the present invention.

FIG. 1 is an exemplary fixed bed gasification process flow diagram, wherein filter residue is treated in a fixed bed gasifier.

In Figure 1, the reference numerals represent: 1-filter residue pretreatment, 2-raw coal, 3-gasifier, 4-gasifier slag, 5-crude synthesis gas, 6-crude synthesis gas processing device, 7-recovered hydrocarbons, 8-synthesis gas, 9-fresh Fischer-Tropsch synthesis catalyst, 10-Fischer-Tropsch synthesis reactor, 11-high-temperature gas phase stream at the outlet of Fischer-Tropsch synthesis reactor, 12-heavy oil separator, 13-heavy oil tail gas after cooling, 14-heavy oil, 15-heavy oil filtering device, 16-heavy oil filter residue, 17-heavy wax, 18-heavy wax filtering device, 19-heavy wax filter residue, 20-residue wax, 21-residue wax filtering device, 22-residue wax filter residue, 23-gasifier preheating layer, 24-gasifier dry distillation layer, 25-gasifier reduction layer, 26-gasifier combustion layer, 27-gasifier ash layer.

FIG. 2 is an exemplary coal-water slurry gasification process flow diagram, wherein filter residue is treated in a coal-water slurry gasifier.

In FIG. 2 , the reference numerals represent: 1—filter residue pretreatment, 2—water-coal slurry preparation system, 3—gasification furnace, 4—gasification furnace slag, 5—crude synthesis gas, 6—process burner.

DETAILED DESCRIPTION

The specific embodiments of the present invention are described in detail below. The specific embodiments described here are only used to illustrate and explain the present invention, but are not used to limit the present invention.

In the present invention, unless otherwise specified, the term "a portion" means a proportion greater than 0% and less than 100% relative to the total amount of the object it modifies.

In the present invention, unless otherwise specified, the term "low-carbon oil and gas component" refers to a mixture of C1 to C15 hydrocarbons.

In one embodiment, the present invention provides a flexible gasification method for Fischer-Tropsch synthesis reaction residue in a gasifier, comprising the following steps:

(1) adding a carbon-containing raw material and a Fischer-Tropsch synthesis reaction residue into a gasifier, wherein hydrocarbons in the Fischer-Tropsch synthesis reaction residue undergo a cracking reaction in the gasifier to produce low-carbon oil and gas components and/or methane, and a metal catalyst in the Fischer-Tropsch synthesis reaction residue is oxidized to form an oxidized metal catalyst, and the carbon-containing raw material is gasified to produce a crude synthesis gas;

(2) a portion of the low-carbon oil and gas components and/or methane is oxidized into carbon oxides;

(3) the crude synthesis gas undergoes a water-gas shift reaction under the catalytic action of the oxidized metal catalyst;

(4) The filter aid, oxidized metal catalyst and slag in the Fischer-Tropsch synthesis reaction filter residue are discharged from the gasifier together.

In some embodiments, before step (1), the method further comprises pre-treating the Fischer-Tropsch synthesis reaction residue. In some preferred embodiments, the pre-treating comprises: cooling the Fischer-Tropsch synthesis reaction residue into a solid and crushing it.

In some embodiments, the gasifier is a fixed bed gasifier or a water-coal slurry gasifier.

In some embodiments, the carbonaceous feedstock is added to the gasifier together with the Fischer-Tropsch synthesis reaction residue.

In some embodiments, the Fischer-Tropsch synthesis reaction residue undergoes hydrocarbon cracking reaction in the region of the gasifier >300°C to generate low-carbon oil and gas components; and/or undergoes hydrocarbon cracking reaction in the region of the gasifier >800°C to generate methane. In some preferred embodiments, in step (1), the Fischer-Tropsch synthesis reaction residue undergoes hydrocarbon cracking reaction in the preheating layer and retorting layer of the fixed bed gasifier to generate low-carbon oil and gas components. In some further preferred embodiments, in step (1), the Fischer-Tropsch synthesis reaction residue further undergoes hydrocarbon cracking reaction in the reduction layer and combustion layer of the fixed bed gasifier to generate methane. In some preferred embodiments, in step (1), the Fischer-Tropsch synthesis reaction residue undergoes hydrocarbon cracking reaction in the water-coal slurry gasifier to generate methane.

In some embodiments, in step (1), the oxidized metal catalyst is an iron oxide compound.

In some embodiments, in step (2), the carbon oxide is carbon monoxide or carbon dioxide.

In some embodiments, in step (3), under the catalytic action of the oxidized metal catalyst (e.g., iron oxide compound), the raw synthesis gas and the carbon oxides oxidized from the low-carbon oil and gas components undergo a water-gas shift reaction in the preheating layer and the retorting layer of the fixed bed gasifier to adjust the hydrogen-carbon ratio of the gas at the outlet of the fixed bed gasifier. Alternatively, in some embodiments, in step (3), under the catalytic action of the oxidized metal catalyst (e.g., iron oxide compound), the raw synthesis gas undergoes a water-gas shift reaction in the lower part of the water-coal slurry gasifier to adjust the hydrogen-carbon ratio of the gas at the outlet of the water-coal slurry gasifier. The heat released by the water-gas shift reaction can provide heat for the gasification process, thereby improving the overall thermal efficiency of the gasifier; limited by thermodynamic equilibrium, the oxidized metal catalyst (e.g., iron oxide compound) has little effect on the reaction in the reduction layer and combustion layer of the gasifier.

In some embodiments, the hydrogen-to-carbon ratio of the gasifier outlet gas can be further adjusted by increasing the amount of the filter residue added.

Regarding the filter residue, taking a 1 million tons/year coal indirect liquefaction project as an example, the output of slag wax filter residue is about 0.25t/h~0.4t/h, of which the hydrocarbon content is about 50wt%~60wt%, and the iron-based catalyst content is about 40wt%~50wt%; in addition, the output of heavy wax filter residue is about 0.15t/h~0.2t/h, of which the hydrocarbon content is about 35wt%~45wt%, the iron-based catalyst content is <0.1wt%, and the remaining about 55wt%~65wt% is filter aid; in addition, the output of heavy oil filter residue is about 0.05t/h~0.1t/h, of which the hydrocarbon content is about 30wt%~40wt%, the iron-based catalyst content is <5wt%, and the remaining about 60wt%~70wt% is filter aid. In the 1 million tons/year coal indirect liquefaction project, the total output of the three types of filter residues is about 0.5t/h~0.7t/h, which includes: hydrocarbons with a content of about 40wt%~50wt%, iron-based catalysts with a content of about 20wt%~30wt%, and filter aids with a content of about 30wt%~40wt%.

As an example, the above-mentioned filter residue can be added to a fixed bed gasifier, and the hydrocarbons in the filter residue are cracked into low-carbon oil and gas components in the preheating layer and the retorting layer of the fixed bed gasifier, and a part of the low-carbon oil and gas components are oxidized into carbon monoxide or carbon dioxide; the iron-based catalyst in the filter residue is converted into an oxidized state, showing a catalytic effect on the water-gas shift reaction, and can promote the occurrence of the water-gas shift reaction in the preheating layer and the retorting layer of the fixed bed gasifier, thereby achieving the purpose of adjusting the hydrogen-carbon ratio of the outlet gas of the fixed bed gasifier; when the filter residue reaches the reduction layer and the combustion layer of the gasifier, the hydrocarbons in the filter residue are cracked into methane at >800°C, and part of the methane is oxidized into carbon monoxide or carbon dioxide; the filter aid in the filter residue is still in a solid powder state; the remaining residue after the cracking of the hydrocarbon components in the filter residue can be discharged together with the gasification furnace slag.

As another example, the above-mentioned filter residue can be added to a water-coal slurry gasifier, and the hydrocarbons in the filter residue are cracked into methane, and part of the methane is oxidized into carbon monoxide or carbon dioxide; the iron-based catalyst in the filter residue is converted into an oxidized state and catalyzes the water-gas shift reaction of the crude synthesis gas; the filter aid in the filter residue is still in a solid powder state; and the residue after the filter residue is cracked can be discharged together with the gasification furnace slag.

In this paper, by adding Fischer-Tropsch synthesis reaction residue into the gasifier, the synthesis gas content in the gasifier outlet gas can be increased and the hydrogen-carbon ratio can be adjusted, and the methane content in the gasifier outlet gas can also be increased.

Example

The present invention is further described in detail below through examples, but the protection scope of the present invention is not limited to these examples. Those skilled in the art may make other modifications, adjustments or combinations based on the following examples, which also fall within the protection scope of the present invention.

Example 1

The experiment was conducted with the filter residue from the 1 million tons/year coal indirect liquefaction project. The total output of the filter residue obtained after filtering the slag wax discharged from the catalyst replacement, the filter residue obtained after filtering inside the Fischer-Tropsch synthesis reactor and then filtering the filter residue obtained by cooling the gas at the top outlet of the Fischer-Tropsch synthesis reactor to heavy oil is about 0.5t/h~0.7t/h (in terms of mass ratio, the feed ratio of the above three filter residues is 6:3:1), of which the hydrocarbon content is about 40wt%~50wt%, the iron-based catalyst content is about 20wt%~30wt%, and the remaining about 30wt%~40wt% is filter aid. The filter residue is treated by fixed bed pressurized gasification technology. The filter residue contains hydrocarbons, catalysts and filter aids. Next, the flexible gasification process of the Fischer-Tropsch synthesis reaction filter residue in the gasifier will be described in detail:

As shown in Figure 1, the above-mentioned filter residue is cooled to a solid at 20°C and crushed (i.e., slag wax pretreatment). The size of the crushed filter residue is consistent with that of the raw coal (both are 5mm to 50mm), and is added to the fixed bed gasifier together with the raw coal. The filter residue and raw coal are added to the gasifier from the upper part of the gasifier. As the temperature of the gasifier gradually increases from top to bottom, the hydrocarbons in the filter residue undergo cracking reactions in the preheating layer and the dry distillation layer (>300°C) of the gasifier to generate low-carbon oil and gas components, and part of the low-carbon oil and gas components are oxidized to carbon monoxide or carbon dioxide. The iron-based catalyst in the Fischer-Tropsch synthesis reaction filter residue is oxidized to form an iron oxide catalyst. The raw coal is gasified to generate crude synthesis gas.

When the filter residue reaches the reduction layer and the combustion layer of the gasifier, the hydrocarbons in the filter residue are cracked into methane at a temperature of >800° C., and a part of the methane is oxidized into carbon monoxide or carbon dioxide.

Under the catalytic action of the iron oxide catalyst, the crude synthesis gas produced in the gasifier and the carbon oxides oxidized from a part of the low-carbon oil and gas components undergo a water-gas shift reaction in the preheating layer and the dry distillation layer of the gasifier, thereby being able to adjust the hydrogen-carbon ratio of the gas at the outlet of the gasifier, and the heat released by the water-gas shift reaction can provide heat for the gasification process, thereby improving the overall thermal efficiency of the gasifier. As the filter residue enters the reduction layer and the combustion layer of the gasifier, the catalytic effect of the water-gas shift reaction of the iron oxide catalyst therein is weakened due to the thermodynamic equilibrium. The residue after the cracking of the filter residue is discharged together with the gasification furnace slag.

After testing, adding the above-mentioned filter residue to the gasifier can increase the content of synthesis gas (hydrogen and carbon monoxide) in the gasifier outlet gas by about 0.05 vol% to 0.15 vol%, the hydrogen-carbon ratio by about 0.01 to 0.12, the methane content by about 0.03 vol% to 0.30 vol%, and the gasification furnace slag emission by about 0.25 t/h to 0.35 t/h. Therefore, the flexible gasification of the Fischer-Tropsch synthesis reaction filter residue in the fixed bed gasifier improves the economic efficiency of the carbon-containing raw material gasification process.

Example 2

The experiment was conducted with the filter residue from the 1 million tons/year coal indirect liquefaction project. The total output of the filter residue obtained after filtering the slag wax discharged from the catalyst replacement, the filter residue obtained after filtering inside the Fischer-Tropsch synthesis reactor and then filtering the filter residue obtained by cooling the gas at the top outlet of the Fischer-Tropsch synthesis reactor to heavy oil is about 0.5t/h~0.7t/h (in terms of mass ratio, the feed ratio of the above three filter residues is 6:3:1), of which the hydrocarbon content is about 40wt%~50wt%, the iron-based catalyst content is about 20wt%~30wt%, and the remaining about 30wt%~40wt% is filter aid. The filter residue is treated by water-coal slurry pressurized gasification technology. The filter residue contains hydrocarbons, catalysts and filter aids. Next, the flexible gasification process of the Fischer-Tropsch synthesis reaction filter residue in the water-coal slurry gasifier will be described in detail:

As shown in FIG2 , the filter residue is cooled to a solid at 20° C. and crushed (i.e., pretreatment of the residue wax), crushed into 40 μm to 400 μm particles, and then sent to a coal mill together with coal, water, and additives to form a water-coal slurry (coal slurry concentration 55 wt% to 65 wt%), which is then sent to a process burner through a high-pressure coal slurry pump, and then enters the combustion chamber of a water-coal slurry gasifier through the process burner to undergo a gasification reaction. Due to the high gasification reaction temperature (>1000° C.), the hydrocarbons in the filter residue undergo a deep cracking reaction to generate methane, and a portion of the methane is oxidized to carbon monoxide or carbon dioxide. The iron-based catalyst in the filter residue is oxidized to iron oxide compounds after entering the gasifier. The coal is gasified to generate a crude synthesis gas.

When the crude synthesis gas enters the lower part of the gasifier, the iron oxide compound catalyzes the water-gas shift reaction of the crude synthesis gas, thereby adjusting the hydrogen-carbon ratio of the gas at the outlet of the gasifier. The residue after the filter residue is cracked is discharged together with the gasifier slag.

After measurement, after adding the above-mentioned filter residue to the gasifier, the content of synthesis gas (hydrogen and carbon monoxide) in the outlet gas of the gasifier can be increased by about 0.03vol% to 0.09vol%, the hydrogen-carbon ratio can be increased by about 0.01 to 0.07, the methane content can be increased by about 0.18vol% to 0.49vol%, and the emission of gasification furnace slag can be increased by about 0.25t/h to 0.35t/h. Therefore, the flexible gasification of the filter residue of the Fischer-Tropsch synthesis reaction in the water-coal slurry gasifier also improves the economy of the carbon-containing raw material gasification process.

In the present application, by applying the Fischer-Tropsch synthesis reaction filter residue to a gasifier (including a fixed bed gasifier and a water-coal slurry gasifier), the synthesis gas (hydrogen and carbon monoxide) content and methane content in the gasifier outlet gas can be increased. Since the iron-based Fischer-Tropsch synthesis catalyst is oxidized into an iron oxide compound in the gasifier, it has a certain catalytic activity for the water-gas shift reaction and can catalyze the water-gas shift reaction of the raw coal gas in the gasifier, thereby adjusting the hydrogen-carbon ratio of the gasifier outlet gas. At the same time, the heat released by the water-gas shift reaction can provide heat for the gasification process, thereby improving the overall thermal efficiency of the gasifier.

The method of the present invention not only solves the problem of solid waste (filter residue) treatment in the production process of coal indirect liquefaction projects by flexibly gasifying the Fischer-Tropsch synthesis reaction residue in a gasifier, but also realizes effective resource recovery and utilization of hydrocarbons in the filter residue. It is a safe and economical method for utilizing Fischer-Tropsch synthesis filter residue, and improves the economy of the carbon-containing raw material gasification process.

Claims (10)

1. A flexible gasification method for Fischer-Tropsch synthesis reaction residue in a gasifier, comprising the following steps: (1) adding a carbon-containing raw material and a Fischer-Tropsch synthesis reaction residue into a gasifier, wherein hydrocarbons in the Fischer-Tropsch synthesis reaction residue undergo a cracking reaction in the gasifier to produce low-carbon oil and gas components and/or methane, and a metal catalyst in the Fischer-Tropsch synthesis reaction residue is oxidized to form an oxidized metal catalyst, and the carbon-containing raw material is gasified to produce a crude synthesis gas; (2) a portion of the low-carbon oil and gas components and/or methane is oxidized into carbon oxides; (3) the crude synthesis gas undergoes a water-gas shift reaction under the catalytic action of the oxidized metal catalyst; (4) The filter aid, oxidized metal catalyst and slag in the Fischer-Tropsch synthesis reaction filter residue are discharged from the gasifier together. 2. The method according to claim 1, wherein, before step (1), the method further comprises pretreating the Fischer-Tropsch synthesis reaction residue; Preferably, the pretreatment comprises: cooling the Fischer-Tropsch synthesis reaction residue into a solid and crushing it. 3. The method according to claim 1 or 2, wherein the gasifier is a fixed bed gasifier or a water-coal slurry gasifier. 4. The method according to any one of claims 1 to 3, wherein the carbon-containing raw material is added into the gasifier together with the Fischer-Tropsch synthesis reaction filter residue. 5. The method according to any one of claims 1 to 4, wherein the Fischer-Tropsch synthesis reaction residue undergoes a hydrocarbon cracking reaction in a region of the gasifier at a temperature >300°C to generate low-carbon oil and gas components; and/or undergoes a hydrocarbon cracking reaction in a region of the gasifier at a temperature >800°C to generate methane. 6. The method as claimed in claim 5, wherein the Fischer-Tropsch synthesis reaction residue undergoes hydrocarbon cracking reaction in the preheating layer and the distillation layer of the fixed bed gasifier to generate low-carbon oil and gas components; the Fischer-Tropsch synthesis reaction residue further undergoes hydrocarbon cracking reaction in the reduction layer and the combustion layer of the fixed bed gasifier to generate methane. 7. The method according to claim 5, wherein the Fischer-Tropsch synthesis reaction residue undergoes hydrocarbon cracking reaction in the water-coal slurry gasifier to generate methane. 8. The method according to any one of claims 1 to 7, wherein in step (1), the oxidized metal catalyst is an iron oxide compound. 9. The method according to any one of claims 1 to 8, wherein in step (2), the carbon oxide is carbon monoxide or carbon dioxide. 10. The method according to any one of claims 1 to 9, wherein in step (3), under the catalytic action of the oxidized metal catalyst, the raw synthesis gas and the carbon oxides oxidized from the low-carbon oil and gas components undergo a water-gas shift reaction in the preheating layer and the retorting layer of the fixed bed gasifier; Alternatively, preferably, in step (3), under the catalytic action of the oxidized metal catalyst, the raw synthesis gas undergoes a water-gas shift reaction in the lower part of the water-coal slurry gasifier.