A system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke

Abstract

This invention discloses a system for preparing carbon fibers using low-to-medium temperature coal pyrolysis semi-coke, comprising a water electrolysis device for producing hydrogen and oxygen, a coal pyrolysis furnace, a stirring and mixing device, a catalytic gasification device, and a disproportionation reaction device; the water electrolysis device for producing hydrogen and oxygen is connected to the catalytic gasification device; the coal pyrolysis furnace is connected to the catalytic gasification device via the stirring and mixing device, and the catalytic gasification device is connected to the disproportionation reaction device. This invention not only enables the in-situ gasification of low-to-medium temperature pyrolysis semi-coke into porous carbon, but also enables the production of carbon fibers from the CO produced by the gasification of coal pyrolysis semi-coke through a disproportionation reaction, achieving high-value conversion of coal pyrolysis semi-coke. This invention also achieves in-situ recovery and utilization of CO2, a byproduct of the disproportionation reaction, and there are no technical barriers in terms of equipment or facilities, facilitating industrial or large-scale application.

Description

Technical Field

[0001] This invention belongs to the field of medium- and low-temperature coal pyrolysis semi-coke conversion and utilization, specifically relating to a system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke. Background Technology

[0002] my country's energy structure, characterized by "abundant coal, scarce oil, and limited gas," dictates the crucial role of coal in the country's energy utilization, acting as a "ballast" or "stabilizer" for energy security. Low-rank coal accounts for approximately half of my country's coal reserves, and the medium-to-low temperature pyrolysis of low-rank coal is a potential pathway to achieve graded and differentiated coal conversion and clean, efficient utilization. This not only helps extract oil and gas resources from coal, reducing my country's dependence on imported oil and gas, but also yields semi-coke products with high carbon content and high calorific value (relative to raw coal).

[0003] However, according to reports, by the end of 2020, the Yulin region in northern Shaanxi alone had a coal pyrolysis semi-coke production capacity of 74 million tons, but the output was only about 35 million tons (China Environment News, 2021-12-23. https: / / view.inews.qq.com / a / 20211223A01N9T00). While such large-scale coal pyrolysis technology is beneficial for obtaining large quantities of coal tar and pyrolysis gas, and for upgrading low-rank coal (obtaining coal pyrolysis semi-coke with a higher calorific value than raw coal), it also faces the problem of overcapacity in coal pyrolysis semi-coke production and the actual need for high-value utilization. The traditional use of coal pyrolysis semi-coke as fuel will face increasingly severe environmental pressure.

[0004] The massive emissions of CO2 have triggered serious climate, social, and environmental problems, which has also provided impetus for the conversion and utilization of CO2. If CO2 can be converted into chemical raw materials or fuels, it will help alleviate the exacerbation of these problems and achieve the recycling of CO2.

[0005] Based on this, in order to promote the combination of high-value conversion and CO2 utilization of medium- and low-temperature coal pyrolysis semi-coke and to develop new process technologies, it is necessary to propose a system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke. Summary of the Invention

[0006] To address the technical challenges of synergistic conversion and utilization of medium- and low-temperature coal pyrolysis semi-coke and CO2, and to achieve a combination of high-value conversion and CO2 utilization of medium- and low-temperature coal pyrolysis semi-coke and develop new process technologies, this invention proposes a system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke includes an electrolysis water hydrogen and oxygen production device, a coal pyrolysis furnace, a stirring and mixing device, a catalytic gasification device, and a disproportionation reaction device.

[0009] The water electrolysis unit for producing hydrogen and oxygen is connected to the catalytic gasification unit; the coal pyrolysis furnace is connected to the catalytic gasification unit via a stirring and mixing device, and the catalytic gasification unit is connected to the disproportionation reaction unit.

[0010] Furthermore, the water electrolysis hydrogen and oxygen production unit is connected to a generator set.

[0011] Furthermore, the water electrolysis hydrogen and oxygen production unit is connected to the catalytic gasification unit via an oxygen storage tank.

[0012] Furthermore, the oxygen storage tank is equipped with a circulating gas compression device.

[0013] Furthermore, the coal pyrolysis furnace is also connected to a purification treatment device.

[0014] Furthermore, a gas separation device is connected to the gas separation device.

[0015] Furthermore, the outlet of the gas separation device is divided into two paths: one path is connected to the disproportionation reaction device, and the other path is connected to the catalytic gasification device.

[0016] Furthermore, the catalytic gasification unit is connected to a solid separation and processing unit.

[0017] Furthermore, the solid separation and processing device is connected to the stirring and mixing device.

[0018] Furthermore, the mixing device is equipped with a catalyst feed port, and the solid separation and processing device is connected to the catalyst feed port.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention effectively couples the hydrogen and oxygen production process using water electrolysis, a coal pyrolysis furnace, a catalytic gasification unit, and a disproportionation reaction unit. It utilizes surplus electricity generated during peak periods from clean and renewable energy sources such as wind and solar power to produce hydrogen and oxygen through water electrolysis, while simultaneously enabling the on-site conversion of the produced oxygen (used for catalytic gasification of low-temperature pyrolysis semi-coke into CO-rich gas). The system for preparing carbon fibers using low-temperature coal pyrolysis semi-coke proposed in this invention successfully achieves the coupling and integrated innovation of low-temperature coal pyrolysis and water electrolysis for hydrogen and oxygen production, developing and enriching product types and added value. It not only enables the on-site partial gasification of low-temperature pyrolysis semi-coke into porous carbon (whose value is far higher than that of coal pyrolysis semi-coke), but also allows the CO produced from coal pyrolysis semi-coke gasification to produce carbon fiber (whose value is far higher than that of coal pyrolysis semi-coke) through a disproportionation reaction, achieving high-value conversion of coal pyrolysis semi-coke. The present invention proposes a system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke. The semi-coke is mixed with a certain amount of catalyst and first used in a catalytic gasification reaction. Then, the CO-rich gas produced by the catalytic gasification reaction undergoes a disproportionation reaction (2CO = CO2 + C). 碳纤维 The CO2 byproduct of the disproportionation reaction is then recovered and reused in the catalytic gasification reactor. Its key advantages are: First, under the combined action of the catalyst and CO2, it can inhibit the deep reaction between coal decomposition semi-coke and oxygen, thus promoting the directional generation of CO-rich gas and porous carbon, rather than generating CO2 gas (3C). 半焦 +O2+CO2=4CO). Secondly, it achieves in-situ recovery and utilization of CO2, a byproduct of the disproportionation reaction, reducing carbon emissions and improving process economy. The system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke proposed in this invention provides a potential pathway for the high-value utilization of medium- and low-temperature coal pyrolysis semi-coke (commonly known as semi-coke in northern Shaanxi). The main equipment in the system proposed in this invention can all adopt traditional equipment that has been commercially produced, and there are no technical barriers in terms of equipment and facilities, which facilitates large-scale production or market promotion. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke provided by the present invention.

[0022] Among them, 1-generator set; 2-hydrogen and oxygen production device by water electrolysis; 3-oxygen storage tank; 4-circulating gas compression device; 5-coal pyrolysis furnace; 6-purification treatment device; 7-stirring and mixing device; 8-catalytic gasification device; 9-solid separation treatment device; 10-disproportionation reaction device; 11-gas separation device. Detailed Implementation

[0023] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0024] In addition, the element in this invention is referred to as "fixed to" or "set on" another element, indicating that it can be directly mounted on another element or directly connected to the body of another element.

[0025] The medium- and low-temperature coal pyrolysis semi-coke in this invention is often called semi-coke in northern Shaanxi.

[0026] See Figure 1 The system for preparing carbon fiber using medium- and low-temperature coal pyrolysis semi-coke provided by the present invention mainly includes eleven main pieces of equipment: a generator set 1, an electrolysis water hydrogen and oxygen production device 2, an oxygen storage tank 3, a circulating gas compression device 4, a coal pyrolysis furnace 5, a purification treatment device 6, a stirring and mixing device 7, a catalytic gasification device 8, a solid separation treatment device 9, a disproportionation reaction device 10, and a gas separation device 11.

[0027] The generator set 1 is connected to the water electrolysis hydrogen and oxygen production unit 2, which is also equipped with a water feeding port and a product hydrogen output port. The water electrolysis hydrogen and oxygen production unit 2 is connected to the oxygen storage tank 3. The oxygen storage tank 3 is equipped with a connection port for a circulating gas compression device, which facilitates the compression and storage of oxygen and helps to increase the oxygen storage capacity with a fixed storage tank capacity.

[0028] The coal pyrolysis furnace 5 is equipped with a coal feeding port, a pyrolysis gas outlet, a semi-coke outlet, and a tar outlet. The pyrolysis gas outlet of the coal pyrolysis furnace 5 is connected to the purification treatment device 6, and the semi-coke outlet of the coal pyrolysis furnace 5 is connected to the stirring and mixing device 7. The semi-coke outlet of the coal pyrolysis furnace 5 can also directly output semi-coke. The stirring and mixing device 7 is equipped with a catalyst feeding port and is connected to the catalytic gasification device 8. The oxygen storage tank 3 is connected to the catalytic gasification device 8, and the oxygen storage tank 3 can provide a relatively stable oxygen feedstock to the catalytic gasification device of the coal pyrolysis semi-coke.

[0029] The catalytic gasification device 8 is equipped with two material outlets: one for outputting CO-rich gas after the reaction, which is connected to the disproportionation reaction device 10; and the other for outputting solids after the reaction, which is connected to the solid separation and treatment device 9.

[0030] The disproportionation reactor 10 has two material outlets. One outlet is used for the output of carbon fiber products, and the other outlet is connected to the gas separator 11. The gas separator 11 also has two material outlets. One outlet is connected to the disproportionation reactor 10 and can recycle the recovered CO-rich gas back into the disproportionation reactor 10. The other outlet is used to transport the recovered CO2-rich gas to the catalytic gasification unit 8, realizing the recovery and utilization of the by-product CO2.

[0031] The solid separation and processing device 9 is provided with two connection ports. One connection port is directly used to output porous carbon products, and the other connection port is connected to the stirring and mixing device 7, which can transport the recovered catalyst to the stirring and mixing device 7.

[0032] Generator set 1 generates electricity using wind and / or solar power, providing power to the water electrolysis hydrogen and oxygen production unit 2. The oxygen produced by the water electrolysis hydrogen and oxygen production unit 2 is temporarily stored in oxygen storage tank 3, which stores the produced oxygen; while the produced hydrogen can be directly output to the outside of the system. Oxygen storage tank 3 is equipped with a circulating gas compression device 4, facilitating the compressed storage of oxygen and increasing the oxygen storage capacity within a given capacity. Oxygen storage tank 3 is connected to catalytic gasification unit 8, providing a relatively stable oxygen feedstock to catalytic gasification unit 8.

[0033] After coal undergoes a low-to-medium temperature pyrolysis reaction in the coal pyrolysis furnace 5, the resulting pyrolysis gas is transported to the purification treatment unit 6 for dust removal, desulfurization, and other purification treatments before being output to the outside of the system. One path of the coal pyrolysis semi-coke produced by the coal pyrolysis furnace 5 is directly output to the outside of the system; the other path is transported to the stirring and mixing unit 7 to be stirred and mixed with the catalyst, and then the mixture of coal pyrolysis semi-coke and catalyst is transported to the catalytic gasification unit 8. The stirring and mixing unit 7 is equipped with a catalyst feeding port.

[0034] The mixture of coal pyrolysis semi-coke and catalyst undergoes catalytic gasification in catalytic gasification unit 8 under the combined action of oxygen provided by oxygen storage tank 3 and CO2-rich gas provided by gas separation device 11. The resulting material is output in two streams: one stream is used for outputting CO-rich gas, which is sent to disproportionation reactor 10 as feed gas; the other stream is used for outputting solids, which is connected to solid separation and processing unit 9. The solids from the reaction in catalytic gasification unit 8 are separated in solid separation and processing unit 9. This separation process outputs porous carbon products to the outside of the system and also transfers the recovered catalyst to the catalyst material to achieve catalyst recycling.

[0035] The CO-rich gas from the catalytic gasification unit 8 undergoes a disproportionation reaction in the disproportionation reactor 10. The reacted material in the disproportionation reactor 10 is divided into two output devices: one for outputting solid carbon fiber products, and the other for sending the gas discharged after the reaction to the gas separator 11. After the CO-rich gas is extracted from the tail gas following the disproportionation reaction in the gas separator 11, it is sent back to the disproportionation reactor 10 for CO recovery. The CO2-rich gas recovered in the gas separator 11 is then sent back to the catalytic gasification unit 8 to recover the CO2 byproduct of the disproportionation reaction.

[0036] The system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke proposed in this invention effectively couples a water electrolysis hydrogen and oxygen production device. It can utilize the surplus electricity generated during peak periods of clean and renewable energy generation such as wind and solar power to produce hydrogen and oxygen through water electrolysis, while simultaneously realizing the on-site conversion of the produced oxygen product (used for catalytic gasification of medium- and low-temperature pyrolysis semi-coke into CO-rich gas).

[0037] This invention successfully achieves the coupling and integrated innovation of medium- and low-temperature coal pyrolysis technology and water electrolysis for hydrogen and oxygen production, thus developing and enriching product types and added value. It not only enables the on-site gasification of medium- and low-temperature pyrolysis semi-coke into porous carbon (whose value is far higher than that of coal pyrolysis semi-coke), but also enables the disproportionation reaction of CO produced from coal pyrolysis semi-coke gasification to produce carbon fiber (whose value is far higher than that of coal pyrolysis semi-coke), achieving high-value conversion of coal pyrolysis semi-coke. The main equipment in the system proposed in this invention can all adopt commercially available traditional equipment, and there are no technical barriers in terms of equipment, facilitating large-scale production or market promotion.

[0038] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used in this specification are well known to those skilled in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" includes any combination of one or more of the associated listed items.

Claims

1. A system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke, characterized in that, It includes an electrolysis water hydrogen and oxygen production device (2), a coal pyrolysis furnace (5), a stirring and mixing device (7), a catalytic gasification device (8), and a disproportionation reaction device (10); The water electrolysis hydrogen and oxygen production device (2) is connected to the catalytic gasification device (8); the coal pyrolysis furnace (5) is connected to the catalytic gasification device (8) via the stirring and mixing device (7), and the catalytic gasification device (8) is connected to the disproportionation reaction device (10); the disproportionation reaction device (10) is connected to a gas separation device (11); the outlet of the gas separation device (11) is divided into two paths, one path is connected to the disproportionation reaction device (10), and the other path is connected to the catalytic gasification device (8); the catalytic gasification device (8) is connected to a solid separation and treatment device (9); the solid separation and treatment device (9) is connected to the stirring and mixing device (7); the stirring and mixing device (7) is equipped with a catalyst feeding port, and the solid separation and treatment device (9) is connected to the catalyst feeding port.

2. The system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke according to claim 1, characterized in that, The water electrolysis hydrogen and oxygen production device (2) is connected to a generator set (1).

3. The system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke according to claim 1, characterized in that, The water electrolysis hydrogen and oxygen production device (2) is connected to the catalytic gasification device (8) via the oxygen storage tank (3).

4. The system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke according to claim 3, characterized in that, The oxygen storage tank (3) is equipped with a circulating gas compression device (4).

5. The system for preparing carbon fibers using medium- and low-temperature coal pyrolysis semi-coke according to claim 1, characterized in that, The coal pyrolysis furnace (5) is also connected to a purification treatment device (6).

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