A gas conversion and purification device and method for producing high-purity hydrogen from biogas

Abstract

The present invention discloses a gas conversion and purification device for producing high-purity hydrogen from biogas and a method thereof, which includes a biogas gas cabinet, a water seal tank, a biogas booster, a decarbonization device, a gas booster, a gas preheater, a preheating furnace, a converter, a waste heat boiler, a primary preheater for coal gas, a boiler feed water preheater, a desalted water preheater, a separator, a conversion gas air cooler, a gas-liquid separator, a normal temperature zinc oxide desulfurization tank, a fresh gas filter, a pressure swing adsorption hydrogen extraction device, and a hydrogen compressor; the present invention relies on the coke oven gas conversion device in the existing coke oven gas to methanol system to convert CH4 in the biogas into a mixed gas of H2 and CO2, and then pass it into a pressure swing adsorption system for purification to produce high-purity hydrogen. The device increases the added value of biogas, realizes the organic combination of industrial and agricultural production, and opens up a new way for the utilization of biogas.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a gas conversion and purification device for producing high-purity hydrogen from biogas and a method thereof. Background Art

[0002] In the existing technology, the CH4 content in biogas is about 60%, which is relatively high. Currently, there are two main ways to apply biogas: (1) biogas is used directly as fuel; (2) biogas is decarbonized to produce CNG.

[0003] The utilization rate of biogas by these two approaches is low, and the deep utilization value of biogas as a chemical raw material has not been explored. Summary of the invention

[0004] The purpose of the present invention is to solve the above technical problems existing in the prior art and to provide a gas conversion and purification device and method for producing high-purity hydrogen from biogas, so as to overcome the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a gas conversion and purification device for producing high-purity hydrogen from biogas, which includes a biogas gas holder, a water seal tank, a biogas booster, a decarbonization device, a gas booster, a gas preheater, a preheating furnace, a conversion furnace, a waste heat boiler, a gas primary preheater, a boiler feed water preheater, a desalted water preheater, a separator, a conversion gas air cooler, a gas-liquid separator, a normal temperature zinc oxide desulfurization tank, a fresh gas filter, a pressure swing adsorption hydrogen extraction device, and a hydrogen compressor;

[0006] The outlet of the biogas tank is connected to the inlet of the biogas booster through the water seal tank partition.

[0007] The outlet of the biogas fan is connected to the decarbonization device to remove CO2 from the biogas.

[0008] The outlet of the decarbonization device is connected to the inlet of the gas booster, and the outlet of the gas booster is connected to the shell inlet of the coal gas preheater.

[0009] The pipeline between the outlet of the gas booster and the shell inlet of the coal gas preheater is supplied with saturated steam from the steam outlet of the waste heat boiler, and the amount of steam supplied is adjusted according to the flow rate of the biogas.

[0010] The shell outlet of the gas preheater is connected to the lower inlet of the preheating furnace to heat the mixed gas of biogas and steam.

[0011] The upper inlet of the preheating furnace is connected to the steam outlet of the waste heat boiler to heat the saturated steam.

[0012] The upper outlet of the preheating furnace is connected to the oxygen pipeline from the air separation, and the steam and oxygen are mixed and connected to the inlet of the reforming furnace.

[0013] The lower outlet of the preheating furnace is connected to the inlet of the reforming furnace, and the mixed gas undergoes reforming reaction in the upper part of the preheating furnace.

[0014] The reforming furnace outlet is connected to the reforming gas inlet of the waste heat boiler,

[0015] The reformed gas outlet of the waste heat boiler is connected to the inlet of the gas preheater tube.

[0016] The outlet of the gas preheater tube side is connected to the inlet of the gas primary preheater shell side.

[0017] The shell side outlet of the gas primary preheater is connected to the tube side inlet of the boiler feed water preheater.

[0018] The boiler feed water preheater tube outlet is connected to the desalted water preheater tube inlet,

[0019] The outlet of the desalted water preheater tube is connected to the inlet of the separator, and then the conversion gas is cooled by the conversion gas air cooler, and the cooling water is separated by the gas-liquid separator.

[0020] The outlet of the gas-liquid separator is connected to the inlet of the normal temperature zinc oxide desulfurization tank.

[0021] The outlet of the normal temperature zinc oxide desulfurization tank is connected to the inlet of the fresh air filter.

[0022] The outlet of the fresh gas filter is connected to the inlet of the pressure swing adsorption hydrogen extraction device,

[0023] The outlet of the pressure swing adsorption hydrogen extraction device is connected to the hydrogen compressor, and the hydrogen compressor is connected to the hydrogen loading crane.

[0024] Another aspect of the present invention provides a gas conversion and purification method for producing high-purity hydrogen from biogas, comprising the following steps:

[0025] a. After biogas is pressurized, decarbonization is carried out to reduce the concentration of CO2 in biogas, so as to reduce the impact of CO2 on conversion efficiency;

[0026] b. Steam is added to the decarbonized biogas, and then it is heated step by step through the gas preheater and preheating furnace;

[0027] c. The heated biogas is sent to the converter, where it reacts with oxygen from the air separation;

[0028] d. The converted gas after the reaction is passed through a heating boiler, a gas preheater, a gas primary preheater, a boiler feed water preheater, and a desalted water preheater to recover the converted gas heat;

[0029] e. The conversion gas with recovered heat is purified by a separator, a conversion gas air cooler, a gas-liquid separator, a normal temperature zinc oxide desulfurization tank, and a fresh gas filter;

[0030] f. The purified conversion gas is sent to the pressure swing adsorption hydrogen extraction device for hydrogen extraction, and the hydrogen purity can reach 99.99%;

[0031] g. The hydrogen compressor is connected to the hydrogen loading crane pipe, and the hydrogen is passed into the truck for loading and sale.

[0032] The present invention relies on the coke oven gas conversion device in the existing coke oven gas to methanol system to convert CH4 in biogas into a mixed gas of H2 and CO2, which is then passed into a pressure swing adsorption system for purification to produce high-purity hydrogen. The device increases the added value of biogas, realizes the organic combination of industrial and agricultural production, and opens up a new way for the utilization of biogas. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the present invention.

[0034] In the figure: 1 biogas tank, 2 water seal tank, 3 biogas booster, 4 decarbonization device, 5 gas booster, 6 gas preheater, 7 preheating furnace, 8 conversion furnace, 9 waste heat boiler, 10 gas primary preheater, 11 boiler feed water preheater, 12 desalted water preheater, 13 separator, 14 conversion gas air cooler, 15 gas-liquid separator, 16 room temperature zinc oxide desulfurization tank, 17 fresh gas filter, 18 pressure swing adsorption hydrogen extraction device, 19 hydrogen compressor. DETAILED DESCRIPTION

[0035] Reference Figure 1 In one aspect, the present invention provides a gas conversion and purification device for producing high-purity hydrogen from biogas, which includes a biogas gas holder 1, a water seal tank 2, a biogas booster 3, a decarbonization device 4, a gas booster 5, a gas preheater 6, a preheating furnace 7, a converter 8, a waste heat boiler 9, a gas primary preheater 10, a boiler feed water preheater 11, a desalted water preheater 12, a separator 13, a conversion gas air cooler 14, a gas-liquid separator 15, a normal temperature zinc oxide desulfurization tank 16, a fresh gas filter 17, a pressure swing adsorption hydrogen extraction device 18, and a hydrogen compressor 19;

[0036] The outlet of the biogas tank 1 is connected to the inlet of the biogas booster 3 through the water seal tank partition 2.

[0037] The outlet of the biogas blower 3 is connected to the decarbonization device 4 to remove CO2 from the biogas.

[0038] The outlet of the decarbonization device 4 is connected to the inlet of the gas booster 5, and the outlet of the gas booster 5 is connected to the shell side inlet of the coal gas preheater 6.

[0039] The pipeline between the outlet of the gas booster 5 and the shell inlet of the gas preheater 6 is supplied with saturated steam from the steam outlet of the waste heat boiler 9, and the amount of steam supplied is adjusted according to the flow rate of the biogas.

[0040] The shell outlet of the gas preheater 6 is connected to the lower inlet of the preheating furnace 7 to heat the mixed gas of biogas and steam.

[0041] The upper inlet of the preheating furnace 7 is connected to the steam outlet of the waste heat boiler 9 to heat the saturated steam.

[0042] The upper outlet of the preheating furnace 7 is connected to the oxygen pipeline from the air separation, and the steam and oxygen are mixed and connected to the inlet of the reforming furnace 8.

[0043] The lower outlet of the preheating furnace 7 is connected to the inlet of the reforming furnace 8, and the mixed gas undergoes reforming reaction in the upper part of the preheating furnace.

[0044] The outlet of the reforming furnace 8 is connected to the reforming gas inlet of the waste heat boiler 9.

[0045] The conversion gas outlet of the waste heat boiler 9 is connected to the pipe inlet of the gas preheater 6.

[0046] The tube side outlet of the gas preheater 6 is connected to the shell side inlet of the gas primary preheater 10.

[0047] The shell side outlet of the gas primary preheater 10 is connected to the tube side inlet of the boiler feed water preheater 11.

[0048] The pipe outlet of the boiler feed water preheater 11 is connected to the pipe inlet of the desalted water preheater 12.

[0049] The outlet of the desalted water preheater 12 is connected to the inlet of the separator 13, and then the conversion gas is cooled by the conversion gas air cooler 14, and then the cooling water is separated by the gas-liquid separator 15.

[0050] The outlet of the gas-liquid separator 15 is connected to the inlet of the normal temperature zinc oxide desulfurization tank 16.

[0051] The outlet of the normal temperature zinc oxide desulfurization tank 16 is connected to the inlet of the fresh air filter 17.

[0052] The outlet of the fresh gas filter 17 is connected to the inlet of the pressure swing adsorption hydrogen extraction device 18.

[0053] The outlet of the pressure swing adsorption hydrogen extraction device 18 is connected to the hydrogen compressor 19, and the hydrogen compressor 19 is connected to the hydrogen loading crane.

[0054] Another aspect of the present invention provides a gas conversion and purification method for producing high-purity hydrogen from biogas, comprising the following steps:

[0055] a. After biogas is pressurized, decarbonization is carried out to reduce the concentration of CO2 in biogas, so as to reduce the impact of CO2 on conversion efficiency;

[0056] b. Steam is added to the decarbonized biogas, and then it is heated step by step through the gas preheater and preheating furnace;

[0057] c. The heated biogas is sent to the converter, where it reacts with oxygen from the air separation;

[0058] d. The converted gas after the reaction is passed through a heating boiler, a gas preheater, a gas primary preheater, a boiler feed water preheater, and a desalted water preheater to recover the converted gas heat;

[0059] e. The conversion gas with recovered heat is purified by a separator, a conversion gas air cooler, a gas-liquid separator, a normal temperature zinc oxide desulfurization tank, and a fresh gas filter;

[0060] f. The purified conversion gas is sent to the pressure swing adsorption hydrogen extraction device for hydrogen extraction, and the hydrogen purity can reach 99.99%;

[0061] g. The hydrogen compressor is connected to the hydrogen loading crane pipe, and the hydrogen is passed into the truck for loading and sale.

[0062] The present invention relies on the coke oven gas conversion device in the existing coke oven gas to methanol system to convert CH4 in biogas into a mixed gas of H2 and CO2, which is then passed into a pressure swing adsorption system for purification to produce high-purity hydrogen. The device increases the added value of biogas, realizes the organic combination of industrial and agricultural production, and opens up a new way for the utilization of biogas.

[0063] Specific process flow: biogas passes through the gas cabinet and water seal tank in turn to the biogas booster. The pressurized biogas passes through the decarbonization device to remove CO2. The CH4 content of the decarbonized biogas is above 95%. The decarbonized biogas is pressurized by the booster, with a pressure of about 2.3MPa, and sent to the conversion section at room temperature. In order to meet the needs of the CH4 conversion reaction and to prevent the carbonization of biogas at high temperature, 2.5MPa saturated steam is added to the biogas, and the steam flow rate is adjusted according to the flow rate of biogas. After the addition of steam, the biogas is heated to 420℃ by the coke oven gas preheater, and then preheated to 630℃ by the preheating furnace to enter the upper part of the converter. The oxygen from the air separation is added to the steam preheated by the preheating furnace and enters the converter. The oxygen flow rate is adjusted according to the outlet temperature of the converter (controlled <960℃). The biogas and oxygen react immediately after entering the upper part of the converter, and the conversion gas is drawn out from the bottom of the converter, with a temperature of ≤960℃ and a pressure of about 2.2MPa. The converted gas enters the waste heat boiler to recover heat and produce steam as a byproduct. The temperature of the converted gas drops to about 540°C, and then the coke oven gas and steam are heated by the coke oven gas preheater. The temperature drops to 370°C and enters the coke oven gas primary preheater. After the temperature drops to 270°C, the reaction heat is further recovered by the boiler feed water preheater and the desalted water preheater. The converted gas cooler (evaporative cooler) is cooled to 40°C, and the process condensate is separated by the gas-liquid separator. The residual sulfur in the gas is removed by the zinc oxide desulfurization tank. The converted gas temperature out of the desulfurization tank is 40°C and the pressure is about 2.0MPa. After passing through the filter, it is sent to the pressure swing adsorption hydrogen extraction device for hydrogen extraction. The hydrogen content after hydrogen extraction can reach 99.99%, and then it is pressurized to 17MPa by the hydrogen compressor and sent to the loading station for loading.

Claims

1. A gas conversion and purification device for producing high-purity hydrogen from biogas, characterized by: It includes a biogas tank, a water seal tank, a biogas booster, a decarbonization device, a gas booster, a gas preheater, a preheating furnace, a conversion furnace, a waste heat boiler, a gas primary preheater, a boiler feed water preheater, a desalted water preheater, a separator, a conversion gas air cooler, a gas-liquid separator, a normal temperature zinc oxide desulfurization tank, a fresh gas filter, a pressure swing adsorption hydrogen extraction device, and a hydrogen compressor; The outlet of the biogas tank is connected to the inlet of the biogas booster through the water seal tank partition, the outlet of the biogas fan is connected to the decarbonization device, the outlet of the decarbonization device is connected to the inlet of the gas booster, the outlet of the gas booster is connected to the shell inlet of the gas preheater, the pipeline between the outlet of the gas booster and the shell inlet of the gas preheater has saturated steam from the steam outlet of the waste heat boiler introduced, the shell outlet of the gas preheater is connected to the lower inlet of the preheating furnace, the upper inlet of the preheating furnace is connected to the steam outlet of the waste heat boiler, the upper outlet of the preheating furnace is connected to the oxygen pipeline from the air separation, the steam and oxygen are mixed and connected to the inlet of the converter, the lower outlet of the preheating furnace is connected to the inlet of the converter, and the outlet of the converter is connected to the converted gas inlet of the waste heat boiler. The outlet of the waste heat boiler reformed gas is connected to the inlet of the gas preheater tube side, the outlet of the gas preheater tube side is connected to the inlet of the gas primary preheater shell side, the outlet of the gas primary preheater shell side is connected to the inlet of the boiler feed water preheater tube side, the outlet of the boiler feed water preheater tube side is connected to the inlet of the desalted water preheater tube side, the outlet of the desalted water preheater tube side is connected to the inlet of the separator, the outlet of the gas-liquid separator is connected to the inlet of the normal temperature zinc oxide desulfurization tank, the outlet of the normal temperature zinc oxide desulfurization tank is connected to the inlet of the fresh gas filter, the outlet of the fresh gas filter is connected to the inlet of the pressure swing adsorption hydrogen extraction device, the outlet of the pressure swing adsorption hydrogen extraction device is connected to the hydrogen compressor, and the hydrogen compressor is connected to the hydrogen loading crane pipe.

2. A gas conversion and purification method for producing high-purity hydrogen from biogas, characterized by: The steps include: a. After biogas is pressurized, decarbonization is carried out to reduce the concentration of CO2 in biogas, so as to reduce the impact of CO2 on conversion efficiency; b. Steam is added to the decarbonized biogas, and then it is heated step by step through the gas preheater and preheating furnace; c. The heated biogas is sent to the converter, where it reacts with oxygen from the air separation; d. The converted gas after the reaction is passed through a heating boiler, a gas preheater, a gas primary preheater, a boiler feed water preheater, and a desalted water preheater to recover the converted gas heat; e. The conversion gas with recovered heat is purified by a separator, a conversion gas air cooler, a gas-liquid separator, a normal temperature zinc oxide desulfurization tank, and a fresh gas filter; f. The purified conversion gas is sent to the pressure swing adsorption hydrogen extraction device for hydrogen extraction, and the purity of hydrogen can reach 99.99%; g. The hydrogen compressor is connected to the hydrogen loading crane pipe, and the hydrogen is passed into the truck for loading and sale.

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