System for preparing renewable natural gas from biomass

Abstract

The utility model discloses a system for preparing renewable natural gas by utilizing biomass, which comprises a biomass degradation system, a biomass combustion system, a biomass gasification system and a wind and light energy storage electrolysis system, the biomass degradation system comprises an anaerobic fermentation device, a purification device and a biogas storage tank I which are communicated in sequence, the biomass combustion system comprises a biomass boiler, a carbon dioxide trapping device, a methanation device I and a synthetic natural gas storage tank which are sequentially communicated, and the biomass gasification system comprises a gasification furnace, a methanation device II and a biogas storage tank II which are sequentially communicated. The wind and light energy storage electrolysis system comprises a wind power and photovoltaic power generation system and an electrolytic cell which are sequentially communicated. The biomass recycling system has the advantages that recycling treatment of different types of biomass is realized, and meanwhile, efficient development and utilization of biomass energy are also realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of biomass processing technology, especially to a system for preparing renewable natural gas by using biomass. BACKGROUND

[0002] Natural gas is a high-calorific-value clean fuel easy to transport, and compared with coal and oil, natural gas emits relatively less CO2 and pollutants in its utilization process, is called "low-carbon energy", and is an ideal energy in the world today. However, natural gas is a non-renewable resource, and the reserves in the world are limited, which brings about a serious supply-demand contradiction and then triggers a series of social, economic and other problems. The preparation of renewable natural gas by biochemical or thermochemical conversion of biomass is a green and sustainable energy solution. At the same time, synthetic natural gas is also an effective method to solve the volatility and randomness of solar and wind power generation, and an effective method to absorb surplus power of the power system.

[0003] As the only renewable organic carbon source, biomass has the characteristics of large reserves, wide sources and low environmental impact, and is an important part of renewable energy and an internationally recognized zero-carbon renewable fuel. Biomass resources mainly include agricultural and forestry biomass, livestock manure, municipal organic waste, etc., among which, agricultural and forestry biomass has the simplest composition and the most extensive use. China is rich in biomass waste resources, and about 1 billion tons of biomass waste can be produced annually. Biomass energy has become an important energy in the world today due to its green, renewable and widely distributed nature. Compared with coal, biomass has very low nitrogen and sulfur content, and produces less SO2, NxOy and other pollutants when burned, and is less polluting to the environment than other fossil energy sources. However, the utilization of biomass energy still faces new challenges, such as low utilization rate, slow commercial development, and low economic efficiency, which restrict its development. The resource utilization of biomass waste not only facilitates the recycling of biomass, but also realizes the conversion and utilization of carbon resources in negative carbon biomass. SUMMARY

[0004] The utility model aims at providing a system for preparing renewable natural gas by using biomass, which utilizes anaerobic fermentation and biomass gasification synthesis of biomass to prepare bio-natural gas, utilizes hydrogenation of carbon dioxide produced by direct combustion of biomass and separation of biogas from anaerobic fermentation to prepare synthetic natural gas, realizes resource utilization of different types of biomass, and also realizes efficient development and utilization of biomass energy.

[0005] The above technical purpose of the utility model is realized by the following technical scheme:

[0006] The utility model provides a system for preparing renewable natural gas by using biomass, characterized in that it comprises a biomass degradation system, a biomass combustion system, a biomass gasification system and a wind-solar energy storage electrolysis system, the biomass degradation system comprises an anaerobic fermentation device, a purification device and a biogenic natural gas storage tank I which are sequentially and communicatively arranged, the biomass combustion system comprises a biomass boiler, a carbon dioxide capture device, a methanation device I and a synthetic natural gas storage tank which are sequentially and communicatively arranged, the biomass gasification system comprises a gasification furnace, a methanation device II and a biogenic natural gas storage tank II which are sequentially and communicatively arranged, the wind-solar energy storage electrolysis system comprises a wind power and photovoltaic power generation system and an electrolytic cell which are sequentially and communicatively arranged, an oxygen outlet of the electrolytic cell is communicated with the gasification furnace, two groups of hydrogen outlets of the electrolytic cell are respectively communicated with the methanation device I and the methanation device II, and a carbon dioxide outlet of the purification device is communicated with the carbon dioxide capture device.

[0007] Preferably, the biomass degradation system further comprises a pretreatment device I, a desulfurization device and a liquefied biogenic natural gas storage tank I, the pretreatment device I is communicated with an input port of the anaerobic fermentation device, the pretreatment device I is provided with a biomass input port, the desulfurization device is communicatively arranged between the anaerobic fermentation device and the purification device, and the liquefied biogenic natural gas storage tank I is communicated with an output port of the biogenic natural gas storage tank I.

[0008] Preferably, the anaerobic fermentation device is further provided with a utility steam input port and a biogas slurry output port, and the biogas slurry output port of the anaerobic fermentation device discharges biogas slurry for field utilization.

[0009] Preferably, the biomass combustion system further comprises a pretreatment device II and a liquefied synthetic natural gas storage tank, the pretreatment device II is communicated with an input port of the biomass boiler, the pretreatment device II is provided with a biomass input port, and the liquefied synthetic natural gas storage tank is communicated with an output port of the synthetic natural gas storage tank.

[0010] Preferably, the biomass boiler is further provided with a utility steam output port, a green power output port and an ash output port, the ash output port of the biomass boiler discharges ash for field utilization, and the methanation device II is further provided with a utility steam output port.

[0011] Preferably, the wind-solar energy storage electrolysis system further comprises an energy storage device, a hydrogen storage tank I and a hydrogen storage tank II, the energy storage device is parallelly arranged between the wind power and photovoltaic power generation system and the electrolytic cell, the hydrogen storage tank I and the hydrogen storage tank II are respectively communicated with two groups of hydrogen outlets of the electrolytic cell, the hydrogen storage tank I is communicated with the methanation device I, and the hydrogen storage tank II is communicated with the methanation device II.

[0012] Preferably, the electrolytic cell is further provided with an electrolytic water input port, and the wind power and photovoltaic power generation system is further connected with an external power grid.

[0013] Preferably, the biomass gasification system further comprises a pretreatment device III, a purification device and a liquefied bio natural gas tank II, the pretreatment device III is communicated with the input port of the gasification furnace, the pretreatment device III is provided with a biomass input port, the purification device is communicated and arranged between the gasification furnace and the methanation device II, and the liquefied bio natural gas tank II is communicated with the output port of the bio natural gas tank II.

[0014] Preferably, the gasification furnace is further provided with a plant steam input port and an ash output port, the ash output port of the gasification furnace discharges ash for field utilization, and the methanation device II is further provided with a plant steam output port.

[0015] In summary, the utility model has the following beneficial effects:

[0016] 1. The renewable natural gas is produced by the innovation and organic cooperation of multiple technologies such as biomass anaerobic fermentation, biomass direct combustion, biomass gasification, methane synthesis and natural gas liquefaction, and the green high-value renewable natural gas including bio natural gas and synthetic natural gas is produced, efficient utilization of biomass and consumption of renewable energy are realized, and the application prospect is very wide.

[0017] 2. The carbon dioxide separated and purified by biomass anaerobic fermentation and the carbon dioxide produced by biomass direct combustion are captured, high-purity carbon dioxide is prepared by hydrogenation to prepare synthetic natural gas, hydrogen is supplemented by biomass gasification synthesis gas to prepare synthetic natural gas, zero emission of natural gas preparation is basically realized, and the high value of carbon dioxide is improved.

[0018] 3. The utility model is aimed at different types of biomass for preparing renewable natural gas, the biomass with high water content and easy to biodegrade is prepared into bio natural gas by anaerobic fermentation technology, the biomass with low water content and easy to combust is prepared into green carbon source mainly containing CO2 by direct combustion, and then hydrogenation is prepared into synthetic natural gas, the biomass with low water content and easy to gasify is prepared into green carbon source mainly containing CO by gasification, and then hydrogenation is supplemented to prepare synthetic natural gas, the emission of carbon dioxide is reduced, and the green and clean goal is realized. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the system structure schematic view of the utility model. DETAILED DESCRIPTION

[0020] The specific implementation of the utility model will be further described in combination with the drawings, and the embodiment does not constitute a limitation on the utility model.

[0021] As Figure 1The system for preparing renewable natural gas from biomass includes a biomass degradation system, a biomass combustion system, a biomass gasification system, and a wind-solar energy storage electrolysis system. The biomass degradation system includes an anaerobic fermentation device, a purification device, and a biogenic natural gas storage tank I connected in sequence. The biomass combustion system includes a biomass boiler, a carbon dioxide capture device, a methanation device I, and a synthetic natural gas storage tank connected in sequence. The biomass gasification system includes a gasification furnace, a methanation device II, and a biogenic natural gas storage tank II connected in sequence. The wind-solar energy storage electrolysis system includes a wind power and photovoltaic power generation system and an electrolytic cell connected in sequence. The oxygen outlet of the electrolytic cell is connected with the gasification furnace. Two groups of hydrogen outlets of the electrolytic cell are connected with the methanation device I and the methanation device II respectively. The carbon dioxide outlet of the purification device is connected with the carbon dioxide capture device.

[0022] The biomass degradation system further includes a pretreatment device I, a desulfurization device, and a liquefied biogenic natural gas storage tank I. The pretreatment device I is connected with the input port of the anaerobic fermentation device. The pretreatment device I is provided with a biomass input port. The desulfurization device is connected between the anaerobic fermentation device and the purification device. The liquefied biogenic natural gas storage tank I is connected with the output port of the biogenic natural gas storage tank I.

[0023] The anaerobic fermentation device is further provided with a plant steam input port and a biogas residue and liquid output port. The biogas residue and liquid output port of the anaerobic fermentation device discharges biogas residue and liquid for field utilization.

[0024] The biomass combustion system further includes a pretreatment device II and a liquefied synthetic natural gas storage tank. The pretreatment device II is connected with the input port of the biomass boiler. The pretreatment device II is provided with a biomass input port. The liquefied synthetic natural gas storage tank is connected with the output port of the synthetic natural gas storage tank.

[0025] The biomass boiler is further provided with a plant steam output port, a green power output port, and an ash output port. The ash output port of the biomass boiler discharges ash for field utilization. The methanation device II is further provided with a plant steam output port.

[0026] The wind-solar energy storage electrolysis system further includes an energy storage device, a hydrogen storage tank I, and a hydrogen storage tank II. The energy storage device is connected in parallel between the wind power and photovoltaic power generation system and the electrolytic cell. The hydrogen storage tank I and the hydrogen storage tank II are connected with two groups of hydrogen outlets of the electrolytic cell respectively. The hydrogen storage tank I is connected with the methanation device I. The hydrogen storage tank II is connected with the methanation device II.

[0027] The electrolytic cell is further provided with an electrolytic water input port. The wind power and photovoltaic power generation system is further connected with an external power grid.

[0028] The biomass gasification system further comprises a pretreatment device III, a purification device and a liquefied biogas storage tank II, the pretreatment device III is communicated with the input port of the gasification furnace, the pretreatment device III is provided with a biomass input port, the purification device is communicated and arranged between the gasification furnace and the methanation device II, and the liquefied biogas storage tank II is communicated with the output port of the biogas storage tank II.

[0029] The gasification furnace is further provided with a plant steam input port and an ash output port, the ash output port of the gasification furnace discharges ash for field utilization, and the methanation device II is further provided with a plant steam output port.

[0030] The working process of the utility model is as follows: biomass with high water content and easy biodegradation, such as part of straw, kitchen garbage, livestock and poultry manure and the like, is collected and transported to the pretreatment device I for pretreatment such as sorting, impurity removal and sand removal, the pretreated material enters the anaerobic fermentation device to produce biogas, the temperature of the anaerobic fermentation device is controlled at 35 DEG C, and the residence time is controlled at about 30 days. The biogas produced by the anaerobic fermentation device enters the desulfurization device, the desulfurization device is used for removing particulate matters and hydrogen sulfide in the biogas, the desulfurized biogas enters the purification device for removing carbon dioxide in the biogas to prepare biogas (methane volume fraction ≥ 97%), the separated and removed carbon dioxide enters the carbon dioxide capture device, the biogas enters the biogas storage tank I, and then the biogas is liquefied into LNG and enters the liquefied biogas storage tank I. The residues after the anaerobic fermentation device pass through the dewatering device to produce biogas slurry and biogas residue, which can be utilized in field.

[0031] Biomass with low water content and easy combustion, such as straw, forestry processing residues, part of livestock and poultry manure and the like, is crushed and briquetted by the pretreatment device II and then enters the biomass boiler for combustion, the generated flue gas enters the carbon dioxide capture device after purification, and the separated carbon dioxide of the biogas also enters the carbon dioxide capture device, high-purity carbon dioxide (carbon dioxide volume fraction ≥ 99.5%) can be obtained through the carbon dioxide capture device and used as a raw material for methane synthesis. Then the high-purity carbon dioxide and hydrogen in the hydrogen storage tank I enter the methanation device I to react and produce synthetic natural gas, the pressure of the methanation device is controlled at 3.0 MPa, and the temperature is controlled at 200-600 DEG C, and the steam generated by the methanation device I can be used as plant steam. The generated synthetic natural gas enters the synthetic natural gas storage tank, and then the synthetic natural gas is liquefied into LNG and enters the liquefied synthetic natural gas storage tank.

[0032] The biomass with high moisture content and easy to be gasified, such as part of straw, forestry processing residues, livestock and poultry manure and the like, is crushed and granulated by the pretreatment device III and then enters a biomass gasification furnace to prepare synthesis gas, the pressure of the biomass gasification furnace is controlled at normal pressure or 1.0 MPa, and the temperature is controlled at 800 DEG C. The synthesis gas enters the methanation device II to prepare bio natural gas after being purified, the pressure of the methanation device is controlled at 3.0 MPa, and the temperature is controlled at 250~650 DEG C, the steam generated by the methanation device I can be used for the steam for the plant. The generated bio natural gas enters the bio natural gas storage tank II, and then the generated bio natural gas is liquefied into LNG and enters the liquefied bio natural gas storage tank II.

[0033] The green electricity generated by the photovoltaic and wind power system is transported to the electrolytic tank, and the excess electric energy is stored through the energy storage device. When the electric energy output by the photovoltaic and wind power system exceeds the electric energy required by the electrolytic tank, the excess electric energy is stored through the energy storage device; when the electric energy output by the photovoltaic and wind power system is insufficient, the energy storage device is used to supplement the electric energy required by the electrolytic tank. The electric energy generated by the photovoltaic and wind power system can basically meet the electric energy required by the electrolytic tank. The hydrogen gas generated by the electrolytic tank enters the hydrogen storage tank I and the hydrogen storage tank II and is used for the synthesis of methane in the rear-end chemical device. The hydrogen storage tank I is used to provide the hydrogen consumption required by the methanation device I for producing synthesis natural gas, and the hydrogen storage tank II is used to supplement the hydrogen consumption required by the methanation device II for producing bio natural gas.

[0034] The above only is the preferred embodiment of the present application, and is not used to limit the present application, and the person skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and the modification or equivalent replacement should also be regarded as falling within the protection scope of the technical scheme of the present application.

Claims

1. A system for producing renewable natural gas from biomass, comprising: The system comprises a biomass degradation system, a biomass combustion system, a biomass gasification system and a wind-solar energy storage electrolysis system, the biomass degradation system comprises an anaerobic fermentation device, a purification device and a biological natural gas storage tank I which are sequentially and communicatively connected, the biomass combustion system comprises a biomass boiler, a carbon dioxide capture device, a methanation device I and a synthetic natural gas storage tank which are sequentially and communicatively connected, the biomass gasification system comprises a gasification furnace, a methanation device II and a biological natural gas storage tank II which are sequentially and communicatively connected, the wind-solar energy storage electrolysis system comprises a wind power and photovoltaic power generation system and an electrolytic cell which are sequentially and communicatively connected, an oxygen outlet of the electrolytic cell is communicated with the gasification furnace, two groups of hydrogen outlets of the electrolytic cell are respectively communicated with the methanation device I and the methanation device II, and a carbon dioxide outlet of the purification device is communicated with the carbon dioxide capture device.

2. The system for preparing renewable natural gas using biomass according to claim 1, characterized in that: The biomass degradation system further comprises a pretreatment device I, a desulfurization device and a liquefied biological natural gas storage tank I, the pretreatment device I is communicated with an input port of the anaerobic fermentation device, the pretreatment device I is provided with a biomass input port, the desulfurization device is communicatively arranged between the anaerobic fermentation device and the purification device, and the liquefied biological natural gas storage tank I is communicated with an output port of the biological natural gas storage tank I.

3. The system for producing renewable natural gas from biomass according to claim 1, wherein: The anaerobic fermentation device is further provided with a plant steam input port and a biogas residue and slurry output port, and the biogas residue and slurry output port of the anaerobic fermentation device discharges biogas residue and slurry for field utilization.

4. The system for producing renewable natural gas from biomass according to claim 1, wherein: The biomass combustion system further comprises a pretreatment device II and a liquefied synthetic natural gas storage tank, the pretreatment device II is communicated with an input port of the biomass boiler, the pretreatment device II is provided with a biomass input port, and the liquefied synthetic natural gas storage tank is communicated with an output port of the synthetic natural gas storage tank.

5. The system for producing renewable natural gas from biomass according to claim 1, wherein: The biomass boiler is further provided with a plant steam output port, a green power output port and an ash residue output port, the ash residue output port of the biomass boiler discharges ash residue for field utilization, and the methanation device II is further provided with a plant steam output port.

6. The system for producing renewable natural gas from biomass according to claim 1, wherein: The wind-solar energy storage electrolysis system further comprises an energy storage device, a hydrogen storage tank I and a hydrogen storage tank II, the energy storage device is connected in parallel between the wind power and photovoltaic power generation system and the electrolytic cell, the hydrogen storage tank I and the hydrogen storage tank II are respectively communicated with two groups of hydrogen outlets of the electrolytic cell, the hydrogen storage tank I is communicated with the methanation device I, and the hydrogen storage tank II is communicated with the methanation device II.

7. The system for producing renewable natural gas from biomass according to claim 1, wherein: The electrolytic cell is also provided with an electrolytic water input port, and the wind power and photovoltaic power generation system is further connected with an external power grid.

8. The system for producing renewable natural gas from biomass according to claim 1, wherein: The biomass gasification system further comprises a pretreatment device III, a purification device and a liquefied biological natural gas storage tank II, the pretreatment device III is communicated with an input port of the gasification furnace, the pretreatment device III is provided with a biomass input port, the purification device is communicatively arranged between the gasification furnace and the methanation device II, and the liquefied biological natural gas storage tank II is communicated with an output port of the biological natural gas storage tank II.

9. The system for producing renewable natural gas from biomass according to claim 1, wherein: The gasification furnace is further provided with a plant steam input port and an ash residue output port, the ash residue output port of the gasification furnace discharges ash residue for field utilization, and the methanation device II is further provided with a plant steam output port.

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