CN115505431A - Process and system for manufacturing biological methanol without supplementing hydrogen - Google Patents

Abstract

The invention relates to the technical field of biological methanol, in particular to a process and a system for manufacturing biological methanol without supplementing hydrogen, wherein the process comprises the steps of pyrolysis, gasification, hydrogen production and synthesis; pyrolysis: indirectly heating a biomass raw material in an oxygen-free atmosphere to produce a mixed gas, a mixed liquid of organic acid and tar and a residual carbon solid; and (3) gasification: directly heating the mixed liquid and the carbon residue solid in an anoxic atmosphere to produce a gaseous product and further produce a carbon residue solid; hydrogen production: controlling the reaction temperature of the gaseous product and the carbon residue solid in an oxygen-free or oxygen-deficient atmosphere, and reacting the carbon residue solid with water vapor in the gaseous product to produce hydrogen; synthesizing: the synthesis gas is purified and synthesized to obtain the finished product methanol. The hydrogen-carbon ratio in the synthesis gas is higher than the basic requirement of methanol synthesis, the molar ratio of the hydrogen to the carbon monoxide is more than 2, and the hydrogen does not need to be supplemented from the outside, thereby avoiding the equipment investment and the hydrogen production cost of the hydrogen production by electrolyzing water.

Description

Process and system for manufacturing biological methanol without supplementing hydrogen

Technical Field

The invention relates to the technical field of biological methanol, in particular to a process and a system for preparing biological methanol without supplementing hydrogen.

Background

The methanol prepared by using biomass as a raw material is called biological methanol, is a new liquid energy source without carbon emission, can directly replace petrochemical energy sources, and can also be converted into hydrogen energy sources by a reforming hydrogen production method. The biological methanol can expand the application of the methanol and is beneficial to realizing carbon neutralization of industrial and transportation fuels in China.

The preparation of the biological methanol by using biomass as a raw material can be divided into two process sections: in the first process stage, the solid biomass is converted into synthesis gas mainly comprising hydrogen and carbon monoxide by adopting thermochemical means such as pyrolysis or gasification; the second process section adopts Fischer-Tropsch synthesis or similar process to synthesize methanol from the synthesis gas under certain temperature and pressure. The key is the first process stage, namely high-quality synthesis gas preparation, because the second process stage is mature in process and difficult to reform. High quality syngas needs to meet the following three requirements:

1. the ratio of hydrogen and carbon monoxide meets the basic requirements of methanol synthesis (the molar ratio of hydrogen to carbon monoxide is more than 2);

2. the calorific value of the synthesis gas is high (not less than 2000 kcal/kg) to ensure a sufficiently high chemical energy conversion rate;

3. most of the carbon in the feedstock (not less than 90%) is converted to carbon monoxide in the syngas.

Only the synthetic gas which meets the three basic requirements can prepare the biological methanol which is equivalent to the coal-made methanol in the aspect of economy, otherwise, the biological methanol is difficult to have market competitiveness.

Current domestic and foreign biomass gasifiers are classified into fixed bed gasifiers, moving bed gasifiers, fluidized bed gasifiers, entrained flow gasifiers, cyclone separation bed gasifiers, and the like, according to the type of gasification reactor. Although there are many types, almost none of the gasifiers can satisfy the above three conditions at the same time, which is mainly expressed in that:

1) The hydrogen content in the biomass raw material is seriously insufficient, and the simple gasification process does not meet the hydrogen-carbon ratio condition of the synthetic methanol even if the biomass raw material is completely converted;

2) The synthesis gas generated by simple biomass gasification contains a large amount of impurity gases such as water vapor, carbon dioxide, nitrogen and the like, and the isothermal value is only about 1000 kcal/kg;

3) The biomass gasification furnace generally has about 30 percent of residual carbon, and the carbon conversion rate is lower. Because the biomass gasification furnace can not meet the hydrogen-carbon ratio required by the biological methanol synthesis (requirement 1), a process section for supplementing hydrogen from the outside is required to be added in the existing biological methanol production scheme, for example, the hydrogen is produced by using electrolyzed water. However, the process section increases the investment cost of equipment and the production cost of the biological methanol, so that the biological methanol cannot be compared with the coal-based methanol in the aspect of economy, and the market competitiveness is lost.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a process and a system for manufacturing biological methanol without supplementing hydrogen aiming at the three requirements of the synthetic biological methanol on synthetic gas in the prior art and the current situation that the current biomass gasification furnace cannot be met simultaneously.

The invention adopts the following technical scheme:

in one aspect, the present invention provides a process for producing bio-methanol without hydrogen supplement, comprising:

s1, pyrolysis: indirectly heating the biomass raw material in an oxygen-free atmosphere, controlling the heating temperature to be 450-600 ℃, and producing mixed gas of water, carbon monoxide and carbon dioxide, mixed liquid of organic acid and tar and residual carbon solids;

s2, gasification: directly heating the mixed liquid and the carbon residue solid produced in the step S1 in an oxygen-deficient atmosphere, controlling the gasification temperature to be between 700 and 950 ℃, producing gaseous products of hydrogen and carbon monoxide, and further producing carbon residue solid;

s3, hydrogen production: the gaseous product and the carbon residue solid produced in the step S2 react with water vapor in the gaseous product under the oxygen-free or oxygen-deficient atmosphere and with the reaction temperature controlled between 800 ℃ and 1000 ℃ to produce hydrogen;

s4, synthesis: and (4) forming synthetic gas by the carbon monoxide, the carbon dioxide and the hydrogen generated after the steps S1, S2 and S3, purifying the synthetic gas, conveying the purified synthetic gas to a methanol synthesis process section, and obtaining the finished product methanol by adopting Fischer-Tropsch synthesis.

In any of the possible implementations described above, there is further provided an implementation that the pyrolysis process of step S1 takes 40-60 minutes.

Any of the above possible implementations further provides an implementation that the gasification process time of step S2 is 30-40 minutes.

Any of the possible implementations described above further provides an implementation that the hydrogen production process of step S3 takes 20-30 minutes.

In any one of the foregoing possible implementation manners, there is further provided an implementation manner, in step S1, the oxygen-free atmosphere refers to an excess air coefficient of 0; in step S2, the oxygen-deficient atmosphere refers to an excess air index greater than 0 and less than 1.

Explanation in this application about oxygen-free atmosphere, oxygen-free atmosphere:

the pyrolysis process works in an oxygen-free atmosphere and is in a medium-low temperature region. The fuel gas produced in the process has high calorific value, but low gas content and contains tar, and is suitable for the first process section of synthesis gas production.

The gasification process works in an oxygen-deficient atmosphere and is in a high-temperature region. The gas produced in the process is large in amount, less in tar, but low in calorific value, and is suitable for the second process section for producing the synthesis gas.

Neither the pyrolysis process under the oxygen-free atmosphere nor the gasification process under the oxygen-free atmosphere can independently meet the requirements of high calorific value and large gas amount of the synthesis gas, so that the pyrolysis process and the gasification process need to be tightly combined to jointly produce the synthesis gas reaching the standard.

Explanations in this application regarding direct fever and indirect heating:

the direct heating means that a small amount of air or oxygen (the excess air coefficient is less than 1) is supplied into the reactor, so that part of materials are subjected to oxidation reaction, and the heat generated by the oxidation reaction is used for providing the heat required by the reaction for the rest of materials. Direct heating is mostly used in gasification processes, and gasification products are mainly gaseous. The biomass gasification furnace basically adopts a direct heating mode.

The indirect heating means that all materials do not have oxidation reaction, and only an external heating mode is adopted to provide heat required by the reaction for the materials in the reactor through a certain heat conduction mode. Indirect heating is mostly used in the pyrolysis process, and the pyrolysis product is mainly in a liquid state.

In any of the possible implementations described above, there is further provided an implementation that, in step S4, in the synthesis gas generated after steps S1, S2, S3, the molar ratio of hydrogen to carbon monoxide is greater than 2, the calorific value of the synthesis gas is not less than 3000kcal/kg, and the carbon conversion is not less than 95%.

In any of the above possible implementations, there is further provided an implementation that, in step S2, a gasifying agent is used in the gasification process, the gasifying agent including air, oxygen, water vapor and carbon dioxide. Gasification agents are used in the gasification step and refer to small amounts of air, oxygen, steam, hydrogen, or the like introduced into the reactor to accelerate the gasification process and to adjust the composition and proportions of the syngas.

In any of the possible implementations described above, there is further provided an implementation in which the gasifying agent is selected from pure oxygen or oxygen-enriched air when a low nitrogen content is required in the subsequent synthesis process.

In any of the above possible implementation manners, there is further provided an implementation manner, in the three processes of pyrolysis, gasification and hydrogen production, a heating heat source is provided by fuel combustion, microwave heating or electric heating, and the fuel used is coal, gasoline, diesel oil or natural gas.

Any of the possible implementations described above, further provides an implementation in which a catalyst is used or not used in the gasification process; when a catalyst is used, the catalyst is one or several of Ni-based catalyst, natural ore, alkali and alkaline earth metal. The Ni-based catalyst is used for improving the volume fraction of hydrogen and the removal rate of tar; the natural ore catalyst is used for effectively cracking tar and absorbing carbon dioxide; alkali and alkaline earth metal catalysts are used to accelerate the gasification reaction and reduce the rate of coking.

Any one of the above possible implementation manners further provides an implementation manner, and the three process sections of pyrolysis, gasification and hydrogen production are implemented separately or integrally; when the integrated implementation is adopted, the three process sections are integrated into a set of device, and the device adopts a vertical structure or a horizontal structure.

Any of the above possible implementations further provides an implementation in which the apparatus further comprises a heating unit that provides heat to the three process sections through high temperature resistant piping.

In another aspect, the present invention provides a system for producing bio-methanol without hydrogen supplement, comprising:

a pyrolysis process section: the device is used for heating a biomass raw material in an oxygen-free atmosphere to break macromolecular chains in the biomass into micromolecules; separating out water, hydrogen, carbon monoxide and carbon dioxide to generate mixed gas accompanied with mixed liquid of organic acid and tar and residual carbon solid;

a gasification process stage: heating the mixed liquid and the carbon residue solids produced in the pyrolysis process section under an oxygen-deficient atmosphere to gasify the mixed liquid into gaseous products of hydrogen and carbon monoxide while further producing carbon residue solids;

a hydrogen production process section: the system is used for heating the gaseous product and the carbon residue solid generated in the gasification process section in an oxygen-free or oxygen-deficient atmosphere, and the carbon residue solid and the water vapor in the gaseous product react to produce hydrogen;

a synthesis process section: the system is used for forming synthesis gas from carbon monoxide, carbon dioxide and hydrogen generated in the pyrolysis process section, the gasification process section and the hydrogen production process section, and the synthesis gas is purified and then subjected to Fischer-Tropsch synthesis to obtain a finished product of methanol;

the pyrolysis process section, the gasification process section and the hydrogen production process section are implemented in a split mode or an integrated mode; when the integrated implementation is adopted, the three process sections are integrated into a set of device, and the device adopts a vertical structure or a horizontal structure.

The beneficial effects of the invention are as follows: the conventional biomass gasification technology is improved, and biomass raw materials sequentially pass through three process sections of pyrolysis, gasification and online hydrogen production. The three process sections can be integrated into one set of device or can be decomposed into different devices for implementation. The hydrogen-carbon ratio in the generated synthesis gas is higher than the basic requirement of methanol synthesis (the molar ratio of hydrogen to carbon monoxide is more than 2), and hydrogen does not need to be supplemented from the outside, thereby avoiding the equipment investment and the hydrogen production cost of water electrolysis for hydrogen production.

Drawings

FIG. 1 is a schematic flow diagram of a process for producing bio-methanol without hydrogen supplement according to an embodiment of the present invention.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that technical features or combinations of technical features described in the following embodiments should not be considered as being isolated, and they may be combined with each other to achieve better technical effects.

As shown in fig. 1, a process for producing bio-methanol without hydrogen supplement according to an embodiment of the present invention includes:

s1, pyrolysis: the biomass raw material is indirectly heated in an oxygen-free (also called as absolute oxygen, the coefficient of excess air is 0) atmosphere, the heating temperature is controlled to be 450-600 ℃, in the process section, macromolecular chains in the biomass are broken into micromolecules, mixed gas, mixed liquid of organic acid, tar and the like and residual carbon solid are generated after water (external moisture, internal moisture and combined crystal water), carbon monoxide, carbon dioxide and the like are separated out;

s2, gasification: the mixed liquid and the carbon residue solid produced in the step S1 are directly heated in an oxygen-deficient (also called oxygen-deficient, excess air coefficient is more than 0 and less than 1) atmosphere, the gasification temperature is controlled between 700 and 950 ℃ (in the process section, liquids such as organic acid, tar and the like are gasified into micromolecule fuel gas such as hydrogen, carbon monoxide and the like), gaseous products of hydrogen and carbon monoxide are produced, and carbon residue solid is further produced;

s3, hydrogen production: the gaseous product and the carbon residue solid produced in the step S2 react with water vapor in the gaseous product under the oxygen-free or oxygen-deficient atmosphere and with the reaction temperature controlled between 800 ℃ and 1000 ℃ to produce hydrogen;

s4, synthesis: and (3) forming synthesis gas by the carbon monoxide, the carbon dioxide and the hydrogen generated after the steps S1, S2 and S3, purifying the synthesis gas, conveying the synthesis gas to a methanol synthesis process section, and obtaining the finished product methanol by adopting Fischer-Tropsch synthesis.

The hydrogen production process section is the main innovation point of the invention, and the chemical reaction formula is as follows:

and

it can be seen that the hydrogen production process section has the functions of on-line hydrogen production, hydrogen supplementation improves the hydrogen-carbon ratio, carbon and water required by the reaction are both products of biomass raw materials after pyrolysis and gasification, and the carbon and water are generally not required to be supplemented from the outside and can be supplemented in a small amount according to actual requirements.

In the step S1, the oxygen-free atmosphere refers to an excess air coefficient of 0; in step S2, the oxygen-deficient atmosphere refers to an excess air index greater than 0 and less than 1.

After the combined process of pyrolysis + gasification + hydrogen production, the three aforementioned requirements for the synthesis of biomethanol can be simultaneously met, and several examples have demonstrated that: in the synthesis gas generated after the steps S1, S2 and S3, the molar ratio of (1) hydrogen to carbon monoxide is more than 2, (2), the calorific value of the synthesis gas is not less than 3000kcal/kg, (3), and the carbon conversion rate is not less than 95%.

In one embodiment, in step S3, the gaseous product and the carbon residue solids are thoroughly mixed to increase the reaction efficiency. For example, the gaseous product may be introduced from the lower end of the carbon residue solid.

In one embodiment, in step S2, a gasifying agent is used in the gasification process, the gasifying agent comprising air, oxygen, water vapor and carbon dioxide.

In one embodiment, the gasifying agent is selected from pure oxygen or oxygen-enriched air when low nitrogen content is required in the subsequent synthesis process.

In a specific embodiment, in the three processes of pyrolysis, gasification and hydrogen production, a heating heat source is provided by fuel combustion, microwave heating or electric heating, and the adopted fuel is coal, gasoline, diesel oil or natural gas. A portion of the syngas produced may also be directed back to combustion.

In one embodiment, the gasification process may or may not use a catalyst to achieve the objectives of the present invention; when a catalyst is used, the catalyst is one or several of Ni-based catalyst, natural ore, alkali and alkaline earth metal.

In a specific embodiment, the three process sections of pyrolysis, gasification and hydrogen production are implemented separately or integrally; considering the convenience of material conveying and the minimization of heat loss, three process sections can be selected to be integrated into one set of equipment; when the device is integrally implemented, the device can adopt a vertical structure and also can adopt a horizontal structure.

In one embodiment, when implemented as an integrated unit, the heating units may be integrated into one unit, providing heat to the three process sections through refractory piping.

After the biomass raw material is subjected to three process sections of pyrolysis, gasification and hydrogen production, more than 95% of carbon is converted into carbon monoxide and a small amount of carbon dioxide, and the carbon monoxide and sufficient hydrogen are purified and then are conveyed to a methanol synthesis process section, wherein the synthesis process section can be completed by adopting mature Fischer-Tropsch synthesis.

The Fischer-Tropsch synthesis is an exothermic reaction, the Fischer-Tropsch synthesis purge gas accounts for about 3% -8% of the raw material synthesis gas, the main components of the Fischer-Tropsch synthesis purge gas are hydrogen, carbon monoxide, low-carbon alkane and other small gases, and the Fischer-Tropsch synthesis purge gas can be introduced back to a heating unit of a pre-process (pyrolysis, gasification and hydrogen production) to realize the maximization of energy utilization and further reduce the production cost, so that the Fischer-Tropsch synthesis purge gas can be regarded as a new recycling mode.

The embodiment of the invention provides a biological methanol manufacturing system without supplementing hydrogen, which comprises:

a pyrolysis process section: the device is used for heating a biomass raw material in an oxygen-free atmosphere to break macromolecular chains in the biomass into micromolecules; the water, the hydrogen, the carbon monoxide and the carbon dioxide are separated out to generate mixed gas accompanied with mixed liquid of organic acid and tar and residual carbon solid;

a gasification process stage: heating the mixed liquid and the carbon residue solids produced in the pyrolysis process section under an oxygen-deficient atmosphere to gasify the mixed liquid into gaseous products of hydrogen and carbon monoxide while further producing carbon residue solids;

a hydrogen production process section: the system is used for heating the gaseous product and the carbon residue solid generated in the gasification process section in an oxygen-free or oxygen-deficient atmosphere, and the carbon residue solid and the water vapor in the gaseous product react to produce hydrogen;

a synthesis process section: the system is used for forming synthesis gas from carbon monoxide, carbon dioxide and hydrogen generated in the pyrolysis process section, the gasification process section and the hydrogen production process section, and the synthesis gas is purified and then subjected to Fischer-Tropsch synthesis to obtain a finished product of methanol;

the pyrolysis process section, the gasification process section and the hydrogen production process section are implemented in a split mode or an integrated mode; when the integrated implementation is adopted, the three process sections are integrated into a set of device, and the device adopts a vertical structure or a horizontal structure.

Example 1

In the embodiment, the biomass raw material is yellow pine wood waste, the temperature of the pyrolysis process section is controlled to be 550 ℃, and the reaction time is 50 minutes; the temperature of the gasification process section is controlled to be 850 ℃, the reaction time is 35 minutes, air is used as a gasification agent, and no catalyst is used; the temperature of the hydrogen production process section is controlled to be 950 ℃, and the reaction time is 25 minutes.

The three process sections of biomass pyrolysis, gasification and hydrogen production are integrated into a set of horizontal device, and a heating chamber provides heat in a unified way. The initial ignition of the heating chamber requires an external fuel such as natural gas, diesel or gasoline. After ignition, part of the synthesis gas generated by the three process sections of pyrolysis, gasification and hydrogen production is led back to the heating chamber as fuel, and the other part is provided for the methanol synthesis process section.

The gasification agent in the embodiment is air, and the main components of the synthesis gas output after the biomass is subjected to three process sections of pyrolysis, gasification and hydrogen production are as follows:

watch 1

Example 2

In the embodiment, the biomass raw material is corn straw particles, the control temperature of the pyrolysis process section is 600 ℃, and the reaction time is 40 minutes; the temperature of the gasification process section is controlled to be 900 ℃, the reaction time is 40 minutes, oxygen is used as a gasification agent, and no catalyst is used; the temperature of the hydrogen production process section is controlled to be 900 ℃, and the reaction time is 30 minutes.

The three process sections of biomass pyrolysis, gasification and hydrogen production are integrated into a set of vertical device, and a heating chamber provides heat in a unified way. The initial ignition of the heating chamber requires an external fuel such as natural gas, diesel or gasoline. After ignition, part of the synthesis gas generated by the three process sections of pyrolysis, gasification and hydrogen production is led back to the heating chamber as fuel, and the other part is provided for the methanol synthesis process section.

The gasification agent in the embodiment is oxygen, and the main components of the synthesis gas output after the biomass is subjected to three process stages of pyrolysis, gasification and hydrogen production are as follows:

watch two

The invention improves the conventional biomass gasification technology, and biomass raw materials sequentially pass through three process sections of pyrolysis, gasification and online hydrogen production. The three process sections can be integrated into one set of device or can be decomposed into different devices for implementation. The hydrogen-carbon ratio in the generated synthesis gas is higher than the basic requirement of methanol synthesis (the molar ratio of hydrogen to carbon monoxide is more than 2), and hydrogen does not need to be supplemented from the outside, thereby avoiding the equipment investment and the hydrogen production cost of electrolyzing water to produce hydrogen.

While several embodiments of the present invention have been presented herein, it will be appreciated by those skilled in the art that changes may be made to the embodiments herein without departing from the spirit of the invention. The above examples are merely illustrative and should not be taken as limiting the scope of the invention.

Claims (10)

1. A process for the manufacture of biomethanol without the need for hydrogen supplementation, said process comprising:

s1, pyrolysis: the biomass raw material is indirectly heated in an oxygen-free atmosphere, the heating temperature is controlled to be 450-600 ℃, and mixed gas of water, carbon monoxide and carbon dioxide, mixed liquid of organic acid and tar and residual carbon solid are produced;

s2, gasification: directly heating the mixed liquid and the carbon residue solid produced in the step S1 in an oxygen-deficient atmosphere, controlling the gasification temperature to be between 700 and 950 ℃, producing gaseous products of hydrogen and carbon monoxide, and further producing carbon residue solid;

s3, hydrogen production: the gaseous product and the carbon residue solid produced in the step S2 react with the water vapor in the gaseous product to produce hydrogen under the oxygen-free or oxygen-deficient atmosphere and the reaction temperature is controlled to be between 800 and 1000 ℃;

s4, synthesis: and (3) forming synthesis gas by the carbon monoxide, the carbon dioxide and the hydrogen generated after the steps S1, S2 and S3, purifying the synthesis gas, conveying the synthesis gas to a methanol synthesis process section, and obtaining the finished product methanol by adopting Fischer-Tropsch synthesis.

2. The process for preparing bio-methanol without hydrogen supplement of claim 1, wherein in step S1, the oxygen-free atmosphere means an excess air ratio of 0; in step S2, the oxygen-deficient atmosphere refers to an excess air index greater than 0 and less than 1.

3. A process for producing bio-methanol without hydrogen supplementation according to claim 1, wherein in step S4, the molar ratio of hydrogen to carbon monoxide in the synthesis gas produced after steps S1, S2, S3 is greater than 2, the calorific value of the synthesis gas is not less than 3000kcal/kg, and the carbon conversion is not less than 95%.

4. A process for manufacturing bio-methanol without hydrogen supplement as claimed in claim 1, wherein in step S2, a gasifying agent is used in the gasification process, and the gasifying agent comprises air, oxygen, water vapor or carbon dioxide.

5. A process for the production of bio-methanol without the addition of hydrogen as claimed in claim 4, wherein the gasifying agent is selected from pure oxygen or oxygen-enriched air when a low nitrogen content is required in the subsequent synthesis process.

6. The process for preparing bio-methanol without hydrogen supplement of claim 1, wherein in the three processes of pyrolysis, gasification and hydrogen production, a heating source is provided by means of fuel combustion, microwave heating or electric heating, and the adopted fuel is coal, gasoline, diesel oil or natural gas.

7. A process for the manufacture of bio-methanol without the need for hydrogen make-up according to claim 1, wherein in the gasification process, with or without the use of a catalyst; when the catalyst is used, the catalyst is one or several of Ni-based catalyst, natural ore, alkali and alkaline earth metal.

8. The process for preparing the bio-methanol without supplementing the hydrogen according to claim 1, wherein the three process sections of pyrolysis, gasification and hydrogen production are separately or integrally implemented; when the integrated implementation is adopted, the three process sections are integrated into a set of device, and the device adopts a vertical structure or a horizontal structure.

9. A process for the production of bio-methanol without the addition of hydrogen according to claim 8, wherein the apparatus further comprises a heating unit for supplying heat to the three process sections through high temperature resistant piping.

10. A system for producing bio-methanol without hydrogen supplementation, the system comprising:

a pyrolysis process section: the device is used for heating biomass raw materials in an oxygen-free atmosphere to break macromolecular chains in biomass into micromolecules; separating out water, hydrogen, carbon monoxide and carbon dioxide to generate mixed gas accompanied with mixed liquid of organic acid and tar and residual carbon solid;

a gasification process stage: for heating the mixed liquor and carbon residue solids produced in the pyrolysis process section in an oxygen-deficient atmosphere to gasify the mixed liquor into gaseous products of hydrogen and carbon monoxide while further producing carbon residue solids;

a hydrogen production process section: the system is used for heating the gaseous product and the carbon residue solid generated in the gasification process section in an oxygen-free or oxygen-deficient atmosphere, and the carbon residue solid and the water vapor in the gaseous product react to produce hydrogen;

a synthesis process section: the system is used for forming synthesis gas from carbon monoxide, carbon dioxide and hydrogen generated in the pyrolysis process section, the gasification process section and the hydrogen production process section, and the synthesis gas is purified and then subjected to Fischer-Tropsch synthesis to obtain a finished product of methanol;

the pyrolysis process section, the gasification process section and the hydrogen production process section are implemented in a split mode or an integrated mode; when the integrated implementation is adopted, the three process sections are integrated into a set of device, and the device adopts a vertical structure or a horizontal structure.

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