CN-121975559-A - System and method for preparing synthetic gas and hydrogen by using medium-temperature chemical chains of biogas

CN121975559ACN 121975559 ACN121975559 ACN 121975559ACN-121975559-A

Abstract

The invention provides a system and a method for preparing synthesis gas and hydrogen by using a methane medium-temperature chemical chain, and belongs to the technical field of synthesis gas and hydrogen preparation by using methane medium-temperature chemical chain conversion. The system comprises a methane desulfurization system, a reduction reaction system, a vapor oxidation reaction system, a hydrogen extraction system and an oxygen carrier circulation system, and the method is that the system is adopted, methane is desulfurized firstly, then the purified methane and the oxidized oxygen carrier are subjected to reduction reaction in a reduction reactor, the generated reduced oxygen carrier and vapor are subjected to oxidation reaction in the vapor oxidation reactor, the obtained crude hydrogen is purified into high-purity hydrogen, and heat is recovered through a heat exchange device, the oxygen carrier is recycled.

Inventors

ZHAO RUIHONG
LIU NAIXUAN
YI NAN
LI GUANGYA
LI KUNJIE
NIU XIAOXUE

Assignees

河北科技大学
中康汇能(北京)能源技术有限公司

Dates

Publication Date: 20260505
Application Date: 20260127

Claims (10)

1. The system for preparing the synthesis gas and the hydrogen by using the methane medium-temperature chemical chain is characterized by comprising a methane desulfurization unit, a reduction reaction unit, a steam oxidation reaction unit, a hydrogen extraction unit and an oxygen carrier circulation unit; the biogas desulfurization unit comprises a biogas desulfurization device and is used for removing hydrogen sulfide in raw biogas to obtain purified biogas; The reduction reaction unit comprises a reduction reaction device, which is used for mixing and reacting the purified biogas with an oxidation state oxygen carrier to obtain synthesis gas and a reduction state oxygen carrier; The steam oxidation reaction unit comprises a steam oxidation reaction device, and is used for enabling the reduced oxygen carrier to react with steam in a mixing way to obtain an oxidized oxygen carrier and crude hydrogen; The hydrogen extracting unit comprises a hydrogen extracting device and is used for purifying the crude hydrogen to obtain high-purity hydrogen; The oxygen carrier circulation unit comprises an oxygen carrier circulation device for realizing the transportation of the oxidized oxygen carrier to the reduction reaction device, and the circulation flow and flow control of the oxygen carriers with different valence states among the units.
2. The biogas medium temperature chemical looping synthesis gas and hydrogen system according to claim 1, wherein the oxygen carrier circulation unit further comprises a particle lift device, a riser, a separation device, a particle settling device, and a particle transport device; The particle lifting device is connected with the first feeding port of the separation device through a lifting pipe, the solid discharging port of the separation device is connected with the feeding port of the reduction reaction device, the gas discharging port of the separation device is connected with the feeding port of the particle sedimentation device, and the discharging port of the particle sedimentation device is connected with the second feeding port of the separation device through a particle conveying device.
3. The system for preparing synthesis gas and hydrogen by using the biogas medium-temperature chemical chain according to claim 1 or 2, wherein the biogas desulfurization unit further comprises a gas conveying device and a biogas pretreatment device, the raw material biogas is connected with a feed inlet of the biogas pretreatment device through the gas conveying device, a discharge outlet of the biogas pretreatment device is connected with the feed inlet of the biogas desulfurization device, the discharge outlet of the biogas desulfurization device is connected with the feed end of the reduction reaction unit, and the raw material biogas is subjected to contact reaction with a desulfurizing agent to realize deep desulfurization after being pretreated.
4. The system for preparing synthesis gas and hydrogen by using the biogas medium-temperature chemical chain according to claim 3, wherein the reduction reaction unit further comprises a first gas sealing device and a first heat exchange device, the purified biogas sequentially enters the reduction reaction device through the first heat exchange device and a gas inlet of the reduction reaction device, an air outlet of the reduction reaction device is connected with a synthesis gas collecting pipeline, a material inlet of the reduction reaction device is connected with a material outlet of the first gas sealing device, and a material inlet of the first gas sealing device is connected with a solid material outlet of the separation device.
5. The system for preparing synthesis gas and hydrogen by using the medium-temperature chemical looping of methane according to claim 4, wherein the steam oxidation reaction unit further comprises a second sealing device, a second heat exchange device and a steam air supply source, wherein water generated by condensation of the steam air supply source and the hydrogen extraction device is connected with a gas inlet of the steam oxidation reaction device through the second heat exchange device; the gas outlet of the steam oxidation reaction device is connected with the hydrogen extracting device through the first heat exchange device, the material inlet of the steam oxidation reaction device is connected with the material outlet of the second sealing device, and the material outlet of the steam oxidation reaction device is connected with the material inlet of the particle lifting device.
6. The system for producing synthesis gas and hydrogen from methane medium temperature chemical chains according to claim 1 or 5, wherein the hydrogen extracting unit further comprises a crude hydrogen compressing device, a gas inlet of the crude hydrogen compressing device is connected with a gas outlet of the steam oxidation reaction device, and a gas outlet of the crude hydrogen compressing device is connected with a feed inlet of the hydrogen extracting device; the hydrogen extracting device is provided with a hydrogen outlet and a liquid water outlet, and the liquid water outlet is connected with the input end of the water vapor air supply source to realize the cyclic utilization of water resources.
7. A method for preparing synthesis gas and hydrogen by using a methane medium-temperature chemical chain, which is characterized by adopting the system as claimed in any one of claims 1-6, and comprising the following steps: 1) Raw material biogas is treated by a biogas desulfurization unit to remove hydrogen sulfide, so as to obtain purified biogas; 2) The purified biogas enters a reduction reaction device and undergoes a reduction reaction with an oxidation state oxygen carrier at 550-650 ℃ and 0.1-3 mpa to generate synthesis gas and a reduction state oxygen carrier; 3) The reduced oxygen carrier is conveyed to a steam oxidation reaction device through an oxygen carrier circulation unit, and is subjected to oxidation reaction with steam at 550-650 ℃ and 0.1-3 mpa to generate crude hydrogen and an oxidized oxygen carrier; 4) The crude hydrogen is purified by the hydrogen extraction unit to obtain high-purity hydrogen with the concentration of more than 99.99 percent, and the oxidized oxygen carrier flows back to the reduction reaction device through the oxygen carrier circulation unit to realize cyclic utilization.
8. The method for preparing synthesis gas and hydrogen from methane medium temperature chemical chains according to claim 7, wherein the reduction reaction device and the steam oxidation reaction device are moving bed reactors, and the moving bed reactors are operated in a gas-solid phase countercurrent mode.
9. The method for producing synthesis gas and hydrogen according to claim 7 or 8, wherein the oxygen carrier active component is at least one of nio·fe 3 O 4 、CuO·Fe 3 O 4 and coo·fe 3 O 4 , and the oxygen carrier inert carrier is at least one of Al 2 O 3 、MgAl 2 O 4 、CeO 2 and SiO 2 .
10. The method for preparing synthesis gas and hydrogen by using the medium-temperature chemical looping of biogas as claimed in claim 9, wherein the volume ratio of methane to carbon dioxide in raw material biogas is 1-3, raw material biogas is derived from anaerobic fermentation products of agricultural and forestry waste, livestock and poultry manure or household garbage, and the molar ratio of H 2 /CO in the synthesis gas is 1-2:1.

Description

System and method for preparing synthetic gas and hydrogen by using medium-temperature chemical chains of biogas Technical Field The invention relates to the technical field of synthesis gas and hydrogen production by methane medium-temperature chemical chain conversion, in particular to a system and a method for producing synthesis gas and hydrogen by methane medium-temperature chemical chain. Background The large use of fossil fuels results in global carbon emissions of over 350 million tons per year, a major factor in climate change, which has led to an increase in the frequency and intensity of extreme weather and climate events in recent years. In order to alleviate climate change, reduce extreme weather and climate events, carbon emissions must be reduced, which requires positive response from each energy consuming industry, together with improved energy structure and increased clean energy duty cycle. Biogas is a renewable energy source produced by fermenting agricultural and forestry waste, municipal waste and sewage, and the main component is CH 4、CO2. The biogas can be purified, separated, decarbonized and desulfurized to prepare the biological natural gas, so that the dependence on fossil fuel natural gas can be reduced. Because the marsh gas mainly contains CH 4, the synthesis gas (H 2 and CO) can be prepared by reforming for further utilization. Hydrogen is a good clean energy source, and the utilization of the hydrogen can not generate greenhouse gases, so that the dependence of fossil fuel can be reduced. At present, the hydrogen is mainly prepared from fossil fuel (natural gas and coal), the method can cause a large amount of carbon dioxide emission, the method belongs to ash hydrogen which is the most commonly used and least environment-friendly method at the present stage, the carbon emission is reduced by carbon capture, utilization and sequestration technology on the basis of ash hydrogen, the hydrogen still is still based on fossil fuel, but the carbon emission is reduced to blue hydrogen, and the hydrogen produced by renewable energy sources (solar energy, wind energy, biomass energy and the like) belongs to green hydrogen which is an environment-friendly sustainable preparation method. The chemical chain technology is a novel efficient chemical conversion technology, and a specific chemical reaction is decomposed into a plurality of sub-reactions in different reactors through a medium, so that efficient utilization of raw materials and self-separation of products are realized. The renewable biomass (biogas) is produced into the synthesis gas and the green hydrogen by using a chemical chain technology, so that the energy recycling is realized, the carbon emission is reduced, and the support is provided for further production of the green methanol. Disclosure of Invention The invention aims to provide a system and a method for preparing synthesis gas and hydrogen by using a methane medium-temperature chemical chain, which are used for solving the technical problems. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a system for preparing synthetic gas and hydrogen by a methane medium-temperature chemical chain, which comprises a methane desulfurization unit, a reduction reaction unit, a steam oxidation reaction unit, a hydrogen extraction unit and an oxygen carrier circulation unit; the biogas desulfurization unit comprises a biogas desulfurization device and is used for removing hydrogen sulfide in raw biogas to obtain purified biogas; The reduction reaction unit comprises a reduction reaction device, which is used for mixing and reacting the purified biogas with an oxidation state oxygen carrier to obtain synthesis gas and a reduction state oxygen carrier; The steam oxidation reaction unit comprises a steam oxidation reaction device, and is used for enabling the reduced oxygen carrier to react with steam in a mixing way to obtain an oxidized oxygen carrier and crude hydrogen; The hydrogen extracting unit comprises a hydrogen extracting device and is used for purifying the crude hydrogen to obtain high-purity hydrogen; The oxygen carrier circulation unit comprises an oxygen carrier circulation device for realizing the transportation of the oxidized oxygen carrier to the reduction reaction device, and the circulation flow and flow control of the oxygen carriers with different valence states among the units. Further, the oxygen carrier circulation unit further comprises a particle lifting device, a lifting pipe, a separation device, a particle sedimentation device and a particle conveying device; The particle lifting device is connected with the first feeding port of the separation device through a lifting pipe, the solid discharging port of the separation device is connected with the feeding port of the reduction reaction device, the gas discharging port of the separation device is connected with the feeding po