A method for preparing green hydrogen by hydrogen extraction and carbon reduction of tar distillation residues and biomass co-pyrolysis

Abstract

The application discloses a green hydrogen preparation method for hydrogen extraction and carbon reduction of tar distillation residues and biomass co-pyrolysis, and belongs to the field of organic solid energy utilization. The green hydrogen preparation method for hydrogen extraction and carbon reduction of tar distillation residues and biomass co-pyrolysis comprises the following steps: obtaining tar distillation residues by distilling biomass pyrolysis tar, returning the tar distillation residues to a biomass pyrolysis furnace under the condition of 500-900 DEG C to perform co-thermal conversion with biomass, and performing co-gasification under a CO2-H2O atmosphere to obtain H2, CO and other high-value synthesis gas. The tar distillation residues and the biomass are co-pyrolyzed, CO2 is fully utilized, high-value products such as esters in tar, monocyclic aromatic hydrocarbons and synthesis gas are gradually converted, hydrogen extraction and carbon fixation are achieved, the development of biomass negative carbon conversion technology is promoted, and the implementation of the double carbon target is assisted.

Description

Technical Field

[0001] This invention relates to a method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, belonging to the field of energy utilization technology of organic solid waste. Background Technology

[0002] Biomass possesses characteristics such as renewability, low pollution, abundant resources, and carbon neutrality. The high-efficiency conversion of biomass gasification technology will play a very positive role in solving energy and environmental problems. However, the tar produced by biomass pyrolysis has a high oxygen content, high heavy component content, and is difficult to utilize. If not utilized, it becomes hazardous waste and causes secondary pollution. Utilizing heavy tar can improve the economic and social benefits of biomass gasification. Thermochemical conversion of heavy tar is an important utilization method. Co-pyrolysis of biomass with tar can effectively optimize the effective hydrogen-to-carbon ratio of biomass, thereby optimizing the distribution of pyrolysis products. However, directly returning tar to the biomass pyrolysis furnace for pyrolysis not only corrodes the pipelines but also easily clogs them, affecting the entire biomass gasification process, making it difficult to implement industrially. Furthermore, the light components in the tar cannot be utilized at a high value. Meanwhile, due to the high oxygen content of biomass, the hydrogen content during gasification is low, and CO2 components account for a certain proportion. Reducing CO2 emissions can achieve high-value carbon utilization, contributing to the implementation of dual-carbon goals. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and address the drawbacks of traditional biomass raw material and tar utilization. This invention provides a method for preparing green hydrogen through co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon emissions. By classifying and utilizing the tar in stages, the aromatic-rich tar residue after distillation is co-pyrolyzed with biomass. On the one hand, this increases the hydrogen yield by improving the effective hydrogen-to-carbon ratio; on the other hand, the abundant aromatic rings guide the aromatization of organic components, effectively solidifying the organic carbon in the biomass and reducing carbon emissions during biomass pyrolysis. Then, using CO2-H2O as a carrier gas, the biomass is gasified for targeted hydrogen production, achieving a secondary increase in hydrogen yield and full resource utilization of CO2. This thermochemical conversion method achieves high-value utilization of tar distillation residue, improved green hydrogen yield and quality, reduced CO2 emissions, and efficient conversion of all biomass components. Simultaneously, CO2 is converted into high-value organic carbon products such as esters, monocyclic aromatic hydrocarbons, and syngas during the thermal conversion process, which can be fully utilized subsequently, and the quality of the tar is also significantly improved.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] (1) Tar distillation: Biomass pyrolysis tar is distilled according to the distillation range determination method specified in GB / T18611-2015. The fraction with a temperature <250℃ is light tar. Light tar is hydrorefined to prepare biodiesel. The fraction with a temperature >250℃ is tar distillation residue.

[0006] (2) Co-pyrolysis: The tar distillation residue is solid at room temperature. It is added to the premixer through a screw feeder to fully mix the tar distillation residue with biomass. Then it enters the biomass pyrolysis furnace and is heated to 500-900℃ under a protective atmosphere.

[0007] (3) CO2-H2O gasification: CO2 is introduced into the pyrolysis furnace at a flow rate of 50-200 mL / min and water vapor at a flow rate of 0.5-1.0 g / min, so that biomass and tar distillation residue are fully co-gasified to obtain gases such as hydrogen, CO, CH4 and CO2, and water and biomass pyrolysis tar are obtained in the liquid phase.

[0008] Furthermore, the biomass pyrolysis tar can be recycled to (1) for recycling and distillation to obtain light tar for use.

[0009] Furthermore, the biomass source is lignocellulosic materials such as corn stalks, sawdust, and walnut shells.

[0010] Furthermore, in step (2), the mass ratio of tar distillation residue to biomass is 0-30:100.

[0011] Preferably, in step (2), the mass ratio of tar distillation residue to biomass is 15-30:100.

[0012] The beneficial effects of this invention are as follows: This invention employs a thermochemical conversion method to pyrolyze and gasify biomass and its tar distillation residue, reducing carbon emissions during green hydrogen production. It effectively utilizes hazardous wastes such as tar, enabling graded and differentiated utilization of the tar. The monocyclic aromatic hydrocarbons and esters in the tar obtained through co-pyrolysis are significantly increased, achieving efficient conversion of all components of biomass. Compared to biomass gasification alone, the hydrogen yield from co-pyrolysis increased by 52.23%, CO2 emissions decreased by 44.61%, and biochar yield increased by 52.54%. The reduction in CO2 promotes the increase of monocyclic aromatic hydrocarbons and esters in the tar. The green hydrogen yield obtained is 358.36 mL / g, and CO2 is fully utilized. CO2 is fixed in the esters in biochar and tar and partially converted into CO through resource utilization, promoting carbon emission reduction and contributing to the implementation of dual-carbon goals. Attached Figure Description

[0013] Figure 1A flowchart for green hydrogen production by co-pyrolyzing tar distillation residue with biomass to extract hydrogen and reduce carbon emissions. Detailed Implementation

[0014] The biomass pyrolysis tar used in the following examples and comparative examples came from a pilot-scale corn straw pyrolysis base in Anyang, Henan Province. Group component analysis revealed the following yields: 1.93% for fractions below 120℃, 9.04% for fractions between 120-170℃, 12.86% for fractions between 170-220℃, and 9.41% for fractions between 220-260℃. The bitumen component yield was 36.35%, and the water content was 24.75% (based on the tar moisture content determination). The distillation recovery rate was 94.35%.

[0015] Example 1

[0016] Biomass pyrolysis tar was distilled according to the distillation range determination method specified in national standard GB / T18611-2015 to obtain tar distillation residue with a temperature >250℃. Corn stalks were ground in a CM100M compound grinder. 20g of corn stalks and 3g of tar distillation residue were weighed and premixed, then fed into the pyrolysis reactor. Initially, nitrogen was used as a protective gas at a flow rate of 200mL / min, and the temperature was increased to 800℃ at a heating rate of 10℃ per minute. CO2 was introduced at a flow rate of 50mL / min, and water vapor was simultaneously introduced into the pyrolysis reactor at a flow rate of 0.8g / min. The temperature was maintained at 800℃ for 30min, yielding 358.36mL / g H2, 114.45mL / g CO, and 344.37mL / g CO2. The biochar yield is 20.41%. The liquid products obtained from the pyrolysis furnace include water and biomass pyrolysis tar. The light tar (fractions at <250℃) in the biomass pyrolysis tar can be further distilled off, and the tar distillation residue (fractions at >250℃) is recycled into the gasifier.

[0017] Example 2

[0018] The difference between Example 2 and Example 1 is that "heating to 800°C at a heating rate of 10°C per minute" is changed to "heating to 900°C at a heating rate of 10°C per minute", and the rest is the same as Example 1.

[0019] Example 3

[0020] The difference between Example 3 and Example 1 is that "heating to 800°C at a heating rate of 10°C per minute" is changed to "heating to 700°C at a heating rate of 10°C per minute", and the rest is the same as Example 1.

[0021] Example 4

[0022] The difference between Example 4 and Example 1 is that "weighing 20g of corn stalks and 3g of tar distillation residue and grinding and premixing" is changed to "weighing 20g of corn stalks and 4g of tar distillation residue and grinding and premixing", while the rest is the same as in Example 1.

[0023] Example 5

[0024] The difference between Example 5 and Example 1 is that "weighing 20g of corn stalks and 3g of tar distillation residue and grinding and premixing" is changed to "weighing 20g of corn stalks and 6g of tar distillation residue and grinding and premixing", while the rest is the same as in Example 1.

[0025] Comparative Example 1

[0026] The difference between Comparative Example 1 and Example 1 is that "weighing 20g of corn stalks and 3g of tar distillation residue, grinding and premixing them, and then inputting them into the pyrolysis reactor" is changed to "weighing 23g of corn stalks and inputting them into the pyrolysis reactor". Everything else is the same as in Example 1.

[0027] Comparative Example 2

[0028] The difference between Comparative Example 2 and Example 1 is that "weighing 20g of corn stalks and 3g of tar distillation residue, grinding and premixing them, and then inputting them into the pyrolysis reactor" is changed to "weighing 23g of tar distillation residue, grinding it, and then inputting it into the pyrolysis reactor". Everything else is the same as in Example 1.

[0029] The differences between Comparative Examples 1-6 and Example 1, and the product data are shown in Table 1 below.

[0030] Table 1. Differences between Comparative Examples 1-2 and Examples 1-5, and corresponding product data.

[0031] <![CDATA[H 2 / mL / g]]> <![CDATA[CO 2 / mL / g]]> Biochar yield / % Comparative Example 1 235.40 621.67 13.38 Comparative Example 2 290.09 662.67 21.09 Example 2 278.05 411.63 13.27 Example 3 227.37 379.42 14.82 Example 4 287.95 551.02 12.43 Example 5 289.05 303.05 10.48

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, characterized in that, Includes the following steps: (1) Thoroughly mix the tar distillation residue with biomass and then put it into the biomass pyrolysis furnace. The pyrolysis furnace is heated to 500-900℃ under a protective atmosphere. (2) CO2 and water vapor are simultaneously introduced into the pyrolysis furnace so that the biomass and tar distillation residue are fully co-gasified to obtain pyrolysis gas and liquid phase.

2. The method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, as described in claim 1, is characterized in that... In step (1), the mass ratio of tar distillation residue to biomass is 0-30:

100.

3. The method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, as described in claim 1, is characterized in that... In step (2), the mass ratio of tar distillation residue to biomass is 15-30:

100.

4. The method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, as described in claim 1, is characterized in that... The method for preparing the tar distillation residue in step (1) includes the following steps: separating the biomass pyrolysis tar into a fraction with a temperature <250℃ and a fraction with a temperature >250℃ by distillation. The fraction with a temperature <250℃ is light tar, and the fraction with a temperature >250℃ is the tar distillation residue.

5. The method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, as described in claim 1, is characterized in that... In step (2), the CO2 flow rate is 50-200 mL / min and the steam feed rate is 0.5-1.0 g / min.

6. The method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, as described in claim 1, is characterized in that... The pyrolysis gas in step (2) includes hydrogen, CO, CH4 and CO2.

7. The method for preparing green hydrogen by co-pyrolysis of tar distillation residue and biomass to extract hydrogen and reduce carbon, as described in claim 1, is characterized in that... In step (2), the liquid phase includes water and biomass pyrolysis tar.

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