Continuous preparation and supply method of green hydrogen and method for continuously preparing methane by using green hydrogen

Abstract

The invention discloses a continuous preparation and supply method of green hydrogen, and relates to the technical field of green hydrogen production. Comprising the following steps: (1) generating power by utilizing solar energy, wind energy or tidal energy, introducing the obtained electric energy into an electrolysis center through a line, electrolyzing water by the electrolysis center to produce green oxygen and green hydrogen, and enabling the green oxygen to enter a straw pure-oxygen gasification furnace for gasification reaction to obtain raw material gas; and (2) mixing the raw material gas obtained in the step (1) with green oxygen generated by an electrolysis center, and carrying out pure oxygen combustion in a gas-fired boiler to generate steam and high-purity CO2. According to the method disclosed by the invention, green hydrogen, CO and CO2 can be continuously and stably produced by adopting a straw gasification mode, and particularly, the green hydrogen effectively supplements the unstable green hydrogen production process of wind energy and solar energy, so that the organic combination and supplementation of renewable energy and straw energy are realized. The green hydrogen produced by the method can be used for synthesizing chemicals such as ammonia, methanol, methane and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production and utilization, and in particular to a method for continuously preparing and supplying green hydrogen and a method for continuously preparing methane by utilizing green hydrogen. Background Art

[0002] Green hydrogen is hydrogen produced by new energy (renewable energy). Currently, new energy such as solar energy, wind energy or tidal energy can be used to generate electricity. The hydrogen produced by electrolyzing water using the obtained electricity is green hydrogen. However, the new energy used for electrolyzing water is greatly affected by environmental factors such as season and temperature, and has discontinuous and unstable problems, which affect the production and utilization of green hydrogen. On the other hand, under standard conditions, the density of hydrogen is one ten-thousandth of the density of water. At minus 252.7℃, it is liquid, and its density is only one-fifteenth of that of water. Therefore, hydrogen is difficult to store. The ability to continuously and stably produce green hydrogen has always been an urgent problem to be solved in this field.

[0003] So far, straw utilization has mostly been done by burning or returning it to the field, which cannot effectively utilize agricultural waste. Compared with the first two methods, straw gasification to produce carbon monoxide and hydrogen as fuel or chemical raw materials is a more environmentally friendly method. It can not only reduce the environmental pollution caused by straw burning, but also convert green electricity into chemicals that are easy to store and transport. Existing straw gasification generally uses fluidized bed type gasification to convert straw into carbon monoxide and hydrogen. The conversion rate is low, and the carbon dioxide content in the mixed gas is high, which reduces the calorific value and utilization value of the gas. Using pure oxygen to burn straw to produce gas to collect carbon dioxide, and combining it with hydrogen produced by photovoltaic power and wind power electrolysis to synthesize methanol, alkanes and other chemicals is a low-carbon, environmentally friendly path. The current method is costly and has limited market acceptance. Summary of the invention

[0004] To solve the above problems, the purpose of the present invention is to provide a method for continuously preparing and supplying green hydrogen and a method for continuously preparing methane using green hydrogen, which not only solves the problems existing in the traditional straw gasification process, but also realizes the organic combination of renewable energy and straw energy, and provides a new idea for the green development of the energy industry. With the continuous improvement of technology and the further reduction of costs.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A method for continuously preparing and supplying green hydrogen comprises the following steps:

[0007] Set up solar energy, wind energy or tidal energy power generation equipment; straw pure oxygen gasification furnace and gas boiler, oxygen production and synthetic methane system, and enter the methane transportation system (such as pipeline).

[0008] When solar energy, wind energy or tidal energy is sufficient to generate electricity, the electricity generated by solar energy, wind energy or tidal energy is introduced into the electrolysis center through the line, and the electricity is used to electrolyze water using electrolysis equipment in the electrolysis center to produce oxygen and hydrogen. The hydrogen is used for external supply, and the oxygen is stored for standby use;

[0009]

[0010] When solar energy, wind energy or tidal energy is not enough to generate electricity, a portion of the stored oxygen is continuously introduced into the pure oxygen gasifier filled with straw, so that the straw in the straw pure oxygen gasifier burns in a pure oxygen environment to produce a gasification reaction to obtain raw gas;

[0011] The raw gas includes CO, H2, CO2 and CH4;

[0012] Take a part of the raw gas and mix it with the steam produced by the gas boiler, convert it into H2 and CO2 through carbon monoxide conversion, and purify the H2 before supplying it externally;

[0013] The remaining raw gas is mixed with another part of the stored oxygen and burned in a gas boiler to heat water to produce steam and CO2. The resulting steam is used for carbon monoxide conversion.

[0014] The CO2 obtained after carbon monoxide conversion and the CO2 produced by the gas boiler are recovered for external supply or input into the straw pure oxygen gasification furnace for use as a reducing agent.

[0015] Preferably, when the amount of raw gas required by the user is less than the raw gas produced, the excess raw gas is used to generate electricity through an internal combustion engine or a gas turbine to obtain raw gas electricity, and the obtained raw gas electricity is stored or introduced into the electrolysis center.

[0016] Preferably, the straw pure oxygen gasification furnace is a two-stage or three-stage fixed bed high-temperature gasification furnace, and the gasification temperature is 900-1250°C; when selecting the furnace diameter, the height of the lower slag layer is 0.8-1.1 times the furnace diameter, the height of the middle redox layer is 1.5-4.5 times the furnace diameter, and the height of the upper dry distillation material layer is 1.5-4.5 times the furnace diameter; the gasification intensity is 300-900m 3 / m 2 , the total height is ≥1.5 times the furnace diameter; through the design of double-stage or three-stage fixed bed high-temperature gasification furnace, especially the design of the thickness of each layer in the furnace, the stable operation of the gasification process at high temperature (900-1250℃) is ensured. This design effectively avoids the problems of crossfire and instability caused by the increase of furnace temperature in traditional gasification furnaces, and achieves high efficiency of high-temperature gasification.

[0017] Pure oxygen produced by water electrolysis and CO2 or a small amount of steam produced by straw gasification are used as mixed high-temperature gasifying agents; this design not only improves the gasification efficiency, but also significantly reduces the CO2 content in the output gas (reduced to ≤15%), increases the CO and H2 content (≥70%), and provides high-quality raw gas for subsequent energy utilization.

[0018] Preferably, the outlet gas temperature of the straw pure oxygen gasifier is 75-130° C., ensuring that air and water vapor are not mixed in the straw pure oxygen gasifier, and increasing the reduction of CO2 by high-temperature gasification.

[0019] Preferably, the three-stage fixed-bed high-temperature gasification furnace is divided into a lower slag layer, a middle oxidation-reduction layer and an upper dry distillation separation layer.

[0020] Further preferably, the upper section, the middle section and the lower section can be combined into one, or the upper section, the lower section and the middle section can be combined into one, but the total height or thickness is greater than 1.5-6 times the diameter, and the gasification agent can be oxygen-enriched or a mixture of air and steam to produce fuel gas for heating or as a green energy.

[0021] Preferably, the thickness of the upper dry distillation separation layer is 1 to 4.5 times the furnace diameter, which can stabilize the temperature and airflow distribution in the furnace and reduce the occurrence of layer crossfire. The layer crossfire refers to the interference between flames or hot air flows between different layers in the gasification furnace, resulting in uneven temperature and airflow distribution in the furnace, thereby affecting the gasification efficiency and product quality.

[0022] Preferably, the mechanism of continuous gasification of straw with pure oxygen is divided into two or three sections of fixed bed high temperature gasification furnace; the middle section firmly controls the high temperature of gasification at 900-1250℃ and the 2.5-3.5 long flame produced by the effective components of straw in the middle section furnace chamber which is 1.5-4.5 times thick (high) of the furnace diameter. The upper section has another 1.5-4.5 times thick (high) furnace diameter, half of which is straw dry distillation raw material to completely block the flame and cover and filter heavy dust and crude tar, and the other half is space through the end surface area to make the rising speed of the generated gas stable at 0.1-0.3m / s, so that the heavy dust and crude tar mass (weight) effect cannot sink with the gas flow and be covered by the top material and enter the reduction layer, thereby reducing the mixing of dust and crude tar into the fuel gas.

[0023] Preferably, a slag layer with a thickness of preferably 0.4-1.5 times the furnace diameter is set at the bottom of the straw pure oxygen gasification furnace. The slag layer with a thickness of 0.4-1.5 times the furnace diameter delays, retains oxidation, and reduces the sinking time. At the same time, the gasification agent is fully heat-exchanged to assist oxygenation and high temperature is increased to reduce the oxygen content of the gas to ≤0.9%. The raw gas CO, H2, CH4, and CO2 produced contain CO+H2=70-82%, and CO2=15-17%. The economic value of the raw gas CO2 produced by pure oxygen gasification doubles for every 5% reduction. The key is to achieve a gasification intensity of 300-900m 3 / m2 The straw is continuously gasified with pure oxygen for thousands or tens of thousands of hours every day, ensuring that hundreds or thousands of tons of straw are digested and consumed every day, becoming an inexhaustible green energy source on a large scale and industrial scale.

[0024] China has installed billions of kilowatts of photovoltaic and wind power capacity. It is assumed that 4.2 billion kilowatt-hours of electricity can be used every day to produce electrolytic hydrogen; 1 billion cubic meters of green hydrogen 3 , green oxygen 500 million m 3 That is 1 billion m 3 Green hydrogen, 500 million m 3 Oxygen needs to be matched and digested as an inexhaustible green resource, and the coupled green sources should be combined to obtain non-petrochemical green energy.

[0025] A straw pure oxygen continuous gasification produces CO+H2=70-80% raw material green gas; straw refers to corn straw, wheat straw, rice straw, reed, grass stems, tree branches, and waste generated by agricultural and forestry crops, with an amount of more than several billion tons generated each year. It is proposed to use straw as a synonym for straw. The carbon content of straw is only about 25%, the volatile matter reaches 49%, and the ignition point value is ≤300℃. These are permanently and continuously generated by nature, and are cut by machine, squeezed and dehydrated in time to squeeze out particles using pure oxygen for continuous gasification. A straw pure oxygen continuous gasification produces gas components reaching;

[0026] CO≈41%, H2≈36%, CH4=4%, CO2≤16%, others 3%.

[0027] That is, in the gas produced by continuous pure oxygen gasification of straw: CO+H2≥73%, CO can be directly used as H2≈36% without conversion and can be used with matching green hydrogen to synthesize methane, alcohol, hydrocarbons and even diesel.

[0028] The pure oxygen gasification of straw has been carried out for more than ten years. One type of operation using fluidized bed proves that it is difficult to reach 66% of the output gas CO+H2, resulting in a high cost for synthesizing methane when the CO2 content is higher than 25%. The other type of fixed bed gasification has not seen good continuous high-intensity operation. The reason is that the fixed bed uses high-quality 30-50mm smokeless lump coal, coke particles, and clean coal balls after dry distillation. Its characteristics are: carbon content ≥80%, volatile matter 7-13%, ignition point value ≥600℃, and the test gasification flame is stable at 0.2-0.3m. According to these data, the operating procedures of the fixed bed gasifier are set: the thickness of the oxidation layer is 0.3m, and the thickness of the reduction layer is 0.5m. It is impossible to operate for gasifying straw; according to the carbon content of straw is only 25%, the volatile matter reaches 49%, and the key ignition point value is ≤300℃. It is proposed that how to achieve continuous gasification of straw is divided into A, middle section furnace, B, upper section furnace, C, and lower section furnace, and their respective performance breakthrough points are described.

[0029] A. Middle section furnace:

[0030] Straw pure oxygen continuous gasification is not the same as smokeless coal. The straw contains about 25% carbon, volatile matter reaches 49%, the ignition point is ≤300℃, and the test gasification intensity is 300m 3 / m 2 At 2.5-3.5m, the flame basically breaks through the thickness of the oxidation layer. At 2.5-3.5m, the flame contains trace oxygen and enters the reduction layer to crack CO and H2. After cracking, the material layer above 3.0m needs to absorb heat, and the flame is gradually generated by lack of oxygen. The actual flame is formed at a gasification intensity of 300m. 3 / m 2 The oxidation layer and reduction layer are about 6 meters. In order to stably control the flame layer, the material layer is thickened by 2.0m at the upper and lower ends to form a 10-meter thick furnace as the middle furnace. The gas produced from the upper end has a composition of CO+H2=70-82% and a temperature of ≤230℃ (no flame seedlings exist).

[0031] B. Upper furnace:

[0032] Oxidation and reduction layer: The oxidation of straw will inevitably produce a 2.5-3.5m high-temperature flame starting from the lower middle section to produce CO2, which is reduced and cracked into about 50-70% C0 from the middle section upwards. The cracking of the reduction layer is an endothermic and oxygen-deficient process. At the same time, the straw reduction layer is also absorbing heat. When the oxygen consumption gradually reduces the temperature to ≤300℃, the gas without flames enters the distillation layer, a spatial separation layer, and its bottom is close to the oxidation-reduction layer. Half of the straw is in distillation. In addition to absorbing heat, the focus of distillation is to filter the gas flowing upward from the reduction layer and further absorb heat to maintain the air flow temperature at 70-180℃. The other half of the space is the key to the continuous operation of straw gasification. The upper space uses the end area gas flow velocity to control at 0.1-0.3m / s, which is equivalent to a gasification intensity of 300-900m 3 / m 2 That is, the gasification intensity and the rising speed of the airflow are 0.1-0.3m / s. The heavy dust and crude tar in the gas will settle in the gaps of the distillation raw materials and be covered again and again. Then the material layer slowly sinks into the reduction and oxidation layer. This is the distillation layer and space layer structure designed by repeated operation and debugging from 1997 to 2014. The carbon content is only 25%, the volatile matter reaches 49%, and the ignition point value is ≤300℃. The data is formed, which can achieve thousands of hours of uninterrupted continuous operation, and the automatic control of the furnace top is evenly unloading, and the furnace bottom slag is matched.

[0033] C. Lower furnace:

[0034] The key to achieving thousands of hours of stable operation of straw pure oxygen continuous gasification is to set up an ultra-thick slag layer (including grate); the thickness of the slag layer is about half of the total height of the oxidation layer and the reduction layer, and it slowly sinks from the oxidation layer to form slag. First, it contains high temperature, and second, the straw carbon powder is completely oxidized, and the particle core contains a lot of high-temperature carbon. The lower part uses O2+CO2 mixture as a gasifier to fully absorb heat from the bottom of the slag in a honeycomb state, completely digest the residual carbon, and enter the upper end of the slag to heat the gasifier to several hundred degrees to enter the oxidation layer to help increase the temperature to 900-1250℃. The reduction rate of CO2 in the gasifier is 50-70% when it reaches 1150℃. In the test, CO+H2=70-82% of the gas composition, that is, CO2=15-17% is the goal achieved by straw pure oxygen continuous gasification. If CO2 is 25-35%, the meaning of pure oxygen gasification of straw is basically lost. Therefore, a kind of continuous pure oxygen gasification of straw, the carbon content of straw is only about 25%, the volatile matter reaches 49%, the ignition point value is ≤300℃, and the flame is 2.5-3.5m. The root is changed and reset: the oxidation layer, reduction layer and matching dry distillation and space layer and slag layer structure are synthesized. At the same time, the gasification agent flows from the bottom to the top to a high temperature of several hundred degrees, which is conducive to oxidation and temperature raising, so that CO2 can be better cracked in the reduction layer to reduce CO2. Through the matching slag discharge of the grate, the entire material layer in the furnace slowly and evenly sinks, forming a gas composition of continuous pure oxygen gasification of straw to reach CO2 below 15-17%.

[0035] Straw pure oxygen realizes continuous gasification. The efficiency is formed according to the characteristics of the three furnaces of the middle, upper and lower sections. The pure oxygen gasification energy output per ton of straw without fermentation, weathering and decay is: 1100-1250m 3 Raw gas, take 1100m 3 / t, CO+H2=70-82% is the calculation base.

[0036] Straw is used as a substitute for "biomass" for the following reasons: First, the reality is that new energy is being developed under the name of straw, but in reality, only building boards, wood chips, and sawdust are burned. It is rare to see real straw being used, and straw is still being returned to the field, buried, or naturally decayed and disappears. Second, real straw is used to gasify its own inherent 6% tar, and the flame in the furnace is 2.5-3.5m, which constitutes crossfire, and it is impossible to produce CO+H2≥66%, and the key is that it cannot operate continuously. To put it bluntly: straw has high volatile matter and low ignition point, which is not the same concept as gasifying building boards, wood chips, and sawdust. Therefore, "straw" is used as a substitute for "biomass", and the use of straw is real.

[0037] Preferably, the upper section of this technology adopts an extra-high and extra-thick water jacket design, and its large area of ​​material layer can absorb a large amount of low-temperature heat, raising the water temperature to above 70°C. This design not only improves the absorption efficiency of thermal energy, but also provides sufficient heat source for subsequent thermal energy conversion. As the water flows into the lower and middle sections, these high-temperature hot water or steam continue to participate in the gasification process in the closed and strictly insulated gasifier, and further convert the thermal energy into hot water or saturated steam at a higher temperature (>130°C). This three-stage conversion mechanism greatly improves the thermal energy conversion efficiency of the gasifier, allowing more chemical energy to be converted into usable thermal energy.

[0038] By thickening the dry distillation layer and designing a special three-piece water jacket structure, the layer fire floating phenomenon in the gasifier can be effectively reduced and the heat energy conversion efficiency can be improved. This design idea is of great significance to improving the performance of the gasifier and product quality.

[0039] Preferably, the straw pure oxygen continuous gasification mechanism is divided into two or three sections of fixed bed high temperature gasification furnace settings; the middle section firmly controls the gasification temperature of 900-1250°C and the 2.5-3.5 long flames produced by the straw components in the middle section furnace chamber which is 1.5-4.5 times thick or high; the upper section has a thickness of 1.5-4.5 times the furnace diameter or high, half of which is straw distillation raw materials that completely block the flames and cover and filter heavy dust and crude tar, and the other half is space through the end surface area to stabilize the rising speed of the generated gas at 0.1-0.3m / s, so that the heavy dust and crude tar mass effect cannot sink with the gas flow and be covered by the top material and enter the reduction layer, thereby reducing the mixing of dust and crude tar into the fuel gas.

[0040] Preferably, a slag layer 0.4-1.5 times thick as the furnace diameter is set at the bottom of the straw pure oxygen gasification furnace. The slag layer 0.4-1.5 times thick as the furnace diameter delays, retains oxidation, and reduces the sinking time. At the same time, the gasification agent is fully heat-exchanged to assist oxygen gasification, increase the high temperature reduction, and reduce the oxygen content of the gas to ≤0.9%. The raw gas CO, H2, CH4, and CO2 produced contain CO+H2=70-82%, and CO2=15-17%. The economic value of the raw gas CO2 produced by pure oxygen gasification doubles for every 5% reduction. The key is to achieve a gasification intensity of 300-900m 3 / m 2 The straw is continuously gasified with pure oxygen for thousands or tens of thousands of hours every day, ensuring that hundreds or thousands of tons of straw are digested and consumed every day, becoming an inexhaustible green energy source on a large scale and industrial scale.

[0041] Preferably, CO2 reducing agent; CO2 and O2 are added to oxygen in the following ratio, CO2 = 20%-50%, O2 = 50%-80%, and fully mixed to form a straw pure oxygen reducing agent; when gasifying the straw, it first goes from the lower part of the slag layer to the upper part, from the lower low temperature to the upper high temperature for heat exchange, reaches the upper part of the slag layer to form a high temperature, enters the oxidation layer to react violently and releases ultra-high temperature gas of 900-1300°C, and then enters the reduction layer; the high-temperature CO2 entering the reduction layer collides with the straw C in the reduction layer of the furnace to generate CO2, and the O2 is cracked by the high temperature of 900-1300°C to remove one O and capture C to generate CO; that is, it is reduced to produce 2CO, and at a high temperature of 1050°C, CO2 can reduce CO to about 50%, that is, it is strongly captured by O in the ultra-high temperature CO2 of 900-1300°C to reduce CO.

[0042] Preferably, in order to achieve better straw gasification, a small amount of high-temperature steam is selected as a gasifying agent when CO2 is insufficient, that is, to ensure that the straw particles in the upper layer of more than ten meters thick in the furnace are not soaked for a long time by excessive water vapor and expand and bloom, and cannot form columnar particles to form a honeycomb. Therefore, it is proposed that the slag layer is 0.4-1.5 times the furnace diameter; in order to control and lock the flame length, the oxidation and reduction layers are 1.5-4.5 times the furnace diameter; in order to prevent the generation of gasification dust and crude tar flowing with the fuel gas; the dry distillation and space layers are also 1.5-4.5 times the furnace diameter to effectively settle in the covered material layer.

[0043] The present invention also includes a method for continuously preparing methane from green hydrogen, comprising the following steps:

[0044] After generating electricity using solar energy, wind energy or tidal energy, the resulting electricity is introduced into the electrolysis center through the line. The electrolysis center electrolyzes water to produce oxygen and hydrogen, of which the oxygen enters the straw pure oxygen gasification furnace to undergo a gasification reaction to obtain raw gas; the raw gas includes CO, H2, CO2 and CH4;

[0045] The hydrogen produced by the electrolysis center and the raw gas obtained from the straw pure oxygen gasifier are compressed into the methane synthesis device, and the remaining CO2 in the synthesis is returned to the straw pure oxygen gasifier or recycled. Generally, one ton of straw can react with hydrogen to synthesize methane as shown in Table 3.

[0046] The process of methane synthesis by this technology is: 1100m 3 Raw gas, raw gas CO≈41%+raw material H2≈36%+green hydrogen H2≈50%synthesized CH4=410m 3 + inherent 44m 3 , that is, pure oxygenation of each ton of straw produces 1100m 3 / t raw gas uses O2+CO2 as gasifier to increase the gasification temperature to 1050℃-1300℃, the gasifier ratio per ton of straw is: O2=180-275m 3 / t, CO2=120-240m 3 / t or steam = 150-240kg / t. The gasification reaction equation of the well-proportioned gasifier and straw is:

[0047]

[0048] Simultaneously coupled green hydrogen 550m 3 Synthetic methane 451m 3 + Raw gas inherent 44m 3 , reaching 495m methane 3 .

[0049] The efficiency of straw and clean coal gasification depends on the ratio of gasifier (reducing agent). When the gasifier with steam (water) and oxygen is used for gasification of clean coal containing 80% carbon 3, only a small part of the input mixed steam is oxidized to produce ultra-high temperature, and then the carbon of straw is combined in the cracking reaction with the reduction layer to generate part of 2CO, H2, and O2. The disadvantage is that the efficiency of steam is very low in the cracking process, more than 70% of waste water is generated, and heat energy is absorbed.

[0050] As a raw material, straw contains only about 25% carbon. If steam is used to participate in cracking, water (steam) will inevitably eat the straw carbon. Moreover, the water that cannot be cracked by steam will become condensed water in the upper part of the gasifier to soak the straw particles. When straw is used as a raw material, only about 25% of the carbon content is used, which cannot reduce the violent reaction between straw and oxygen but preserves the carbon.

[0051] The present invention proposes that CO2 from straw pure oxygen gasification is preferred to replace water vapor. The gasification agent with a good ratio of CO2 and pure oxygen is fully heat-exchanged from the high-temperature slag layer to become high-temperature CO2 gas, which basically reaches 900-1300°C before entering the reduction layer. At this time, part of the high-temperature CO2 collides with the hot carbon of the straw to crack (reduce) 2CO and O2, so that the carbon of CO2 and the carbon of the straw are reduced to 2CO+O2. When the temperature reaches 1150°C, the CO2 reduction rate is about 50%. This is the reason why the flame formed by the proton molecules and oxygen during the straw gasification described repeatedly in the present invention is 2.5-3.5m long. Its reduction equation is:

[0052]

[0053] Take a part of the raw gas and mix it with the steam produced by the gas boiler, convert it into H2 and CO2 through carbon monoxide conversion, and purify the H2 before supplying it externally;

[0054] The carbon monoxide conversion refers to the process in which raw gas reacts with the help of steam pressure and temperature to generate carbon dioxide and hydrogen from carbon monoxide.

[0055] The equation for carbon monoxide conversion is:

[0056]

[0057] The process of hydrogen purification is:

[0058] The remaining raw gas is mixed with another part of the stored oxygen and burned in a gas boiler to heat water to produce steam and CO2. The resulting steam is used for carbon monoxide conversion.

[0059] The CO2 remaining after the carbon monoxide conversion of the raw gas and hydrogen extraction is recovered for external supply or input into the straw pure oxygen gasification furnace for use as a reducing agent.

[0060] The principle of using CO2 recovered and input into straw pure oxygen gasifier as reducing agent is:

[0061] CO2 reducing (gasifying) agent; CO2 is mixed into oxygen according to the ratio, preferably: CO2 = 20%-50%, O2 = 50%-80%, and fully mixed to form a straw pure oxygen reducing (gasifying) agent. When gasifying straw, it first goes from the lower part of the slag layer to the upper part, from the lower low temperature to the upper high temperature for heat exchange, and reaches the upper part of the slag layer to form a high temperature and enter the oxidation layer to react violently to release ultra-high temperature (900-1300℃) gas before entering the reduction layer. The high-temperature CO2 that enters the reduction layer collides with the straw C in the furnace (reduction layer) to produce CO2. The O2 is cracked by the high temperature (900-1300℃) to remove one O and capture C to generate CO. That is, it is reduced to produce 2CO. At a high temperature of 1050℃, CO2 can reduce CO to about 50%, that is, it is strongly captured by the O in the ultra-high temperature (900-1300℃) CO2 to reduce CO. Its reaction equation is:

[0062] (Assume that the reducing agent ratio is: O2=50%, CO2=50%)

[0063] Preferably, the raw gas obtained in step ① is subjected to dust removal, electric coke capture or tar washing in the gas before being pressed into the methane synthesis unit, and then treated by an active material (such as activated carbon) adsorption system.

[0064] Compared with the prior art, the present invention has the following advantages:

[0065] The method of the present invention adopts the straw gasification method to continuously and stably produce green hydrogen, CO and CO2. In particular, green hydrogen is an effective supplement to the unstable green hydrogen production process of wind energy and solar energy, realizing the organic combination and supplement of renewable energy and straw energy. The green hydrogen produced by the present invention can be used to synthesize chemicals such as ammonia, methanol, and methane. The present invention can also produce super methane by high-temperature gasification of straw, O2 and CO2 and coupling with electrolytic oxygen and hydrogen. It not only solves the problems of low conversion rate in the traditional straw gasification process, high carbon dioxide content in the mixed gas, and difficult preservation of green hydrogen, but also super methane can be used as a clean energy and is widely used in gas-fired power generation, heating, transportation fuel and other fields, which helps to reduce dependence on fossil fuels. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 Schematic diagram of the process of producing hydrogen from straw and producing oxygen and hydrogen by electrolysis of water;

[0067] Figure 2 For Figure 1 A schematic diagram of the process of producing hydrogen from straw and producing oxygen and hydrogen by electrolyzing water after adding gas boilers and other equipment on the basis of the present invention;

[0068] Figure 3 A schematic flow chart of a comprehensive utilization method of producing hydrogen from straw in another state and producing oxygen and hydrogen by electrolyzing water;

[0069] Figure 4 It is a schematic diagram of the structure of a straw pure oxygen gasifier;

[0070] Figure 5 It is a schematic diagram of the structure of the peripheral water jacket of the straw pure oxygen gasifier. DETAILED DESCRIPTION

[0071] The purpose of the present invention is to provide a method for continuously preparing and supplying green hydrogen and a method for continuously preparing methane using green hydrogen, which is achieved through the following technical solutions:

[0072] The steam described in the present invention is water vapor.

[0073] As renewable energy sources, photovoltaic power and wind power have installed capacities of several billion kilowatts, indicating that these energy sources have great potential and application prospects. However, electrolysis of hydrogen requires a large amount of electricity (≥4kWh / m 3 ), which makes the cost and efficiency of electrolytic hydrogen a key consideration. By combining photovoltaic power and wind power with electrolytic hydrogen technology, the electricity generated by these renewable energy sources can be used to electrolyze water to produce hydrogen, thereby achieving clean energy conversion and storage.

[0074] As an agricultural waste, straw has the advantages of large quantity, renewable and low cost. Through straw gasification technology, straw can be mixed with oxygen and carbon dioxide at high temperature to produce gas rich in CO and H2. This gas can not only be used directly as energy, but also combined with electrolytic hydrogen to further synthesize super methane or other alkane compounds. This coupling technology not only reduces the cost of electrolytic hydrogen (compensated by secondary oxygen value-added), but also realizes the resource utilization of agricultural and forestry waste.

[0075] The CO and H2 contents in the gas produced by straw gasification can reach about 41% and 36% respectively, and also contain a small amount of methane CH4 (4%) and other gases. This high-content CO and H2 gas is very suitable for coupling reaction with electrolytic hydrogen to produce super energy methane or hydrogen energy. In addition, the oxygen produced during the gasification process can be fully used in the gasification reaction itself, realizing the maximum utilization of resources.

[0076] In order to realize the large-scale application of straw gasification and electrolytic hydrogen coupling technology, a block-based implementation method can be adopted. That is, multiple super methane production centers can be established according to the size of local resources and environmental conditions. Each center can process a certain amount of straw and is equipped with corresponding photovoltaic and wind power installed capacity to provide power support. Through the combination of multiple blocks, a large-scale clean energy production network can be formed to meet a wider range of energy needs.

[0077] This straw gasification and electrolytic hydrogen coupling technology not only has significant economic benefits (such as reducing the cost of electrolytic hydrogen and realizing the resource utilization of agricultural and forestry waste, etc.), but also has important environmental benefits. By reducing dependence on fossil fuels and reducing greenhouse gas emissions, this technology helps promote the transformation of energy structure and the realization of sustainable development goals.

[0078] The present invention provides a new idea and approach for producing green and sustainable clean energy by combining photovoltaic power, wind power, straw gasification and electrolytic hydrogen technology. By continuously optimizing technology, reducing costs and improving efficiency, the technology is expected to be more widely used and promoted in the future.

[0079] By matching gas with 100,000 kw photovoltaic power and wind farm output as an example of a block, depending on the size of local resources and environmental conditions, or combining multiple blocks to form a super methane production center, through straw electrolysis oxygen high-temperature gasification technology, combined with photovoltaic power and wind farm electricity, super methane can be efficiently produced. This technology not only realizes the resource utilization of agricultural waste, but also promotes the consumption of renewable energy, with significant economic and environmental benefits. At the same time, the design of this technical block is flexible. It can be combined with multiple blocks according to local resource and environmental conditions to form a super methane production center and improve overall production capacity and efficiency. 100,000 tons of straw can be processed through the technology of the present invention each year to obtain 114 million m3 Gas, of which 21.09 million m3 of electrolytic oxygen can be coupled 3 and electrolytic hydrogen 42.18 million m 3 , producing 49.02 million m3 of super methane 3 The results are shown in Table 1.

[0080] Table 1 Raw gas obtained from 100,000 tons of straw by the method of the present invention

[0081]

[0082]

[0083] It can be seen from the results in Table 1 that straw, as a renewable resource, is converted into a fuel gas rich in CO and H2 through a specific gasification technology, and by cooperating with an electrolytic hydrogen and oxygen coupling system, efficient energy conversion and storage are achieved.

[0084] After the straw is squeezed, the double-wheel teeth squeeze to produce frictional heating and strong impact on the raw materials, causing tar to overflow and form columnar particles with a plasticized surface, which is a significant improvement over traditional gasification technology. This technology not only improves the gasification efficiency, but also reduces the production of harmful substances such as tar. The straw pure oxygen gasifier used in the present invention uses pure oxygen at 900-1250°C, preferably around 1200°C for gasification, which can more effectively convert straw into fuel gas rich in CO and H2. This high temperature condition is conducive to improving the purity and yield of the gas product. The CO and H2 rich in the fuel gas produced by gasification are ideal raw materials for electrolytic hydrogen production, realizing the maximum utilization of resources.

[0085] The medium-sized pure oxygen high-temperature gasifier can digest more than 200 tons of straw every day and produce 25,000m3 of CO+H2=75~82% gas. 3 If 10 to 20 units of gas are combined in counties and districts to form a large-scale pure oxygen gasification center, hundreds to thousands of tons of straw can be digested every day, producing 200,000 to 400,000 m 3 of gas, generating hundreds of thousands of m 3 Hydrogen, electrolytic pure oxygen (green oxygen) 50,000-100,000 m 3 This is of great significance for alleviating local energy pressure and promoting the circular economy. Compared with traditional fossil energy production, the straw gasification and electrolysis hydrogen production process has lower carbon emissions and environmental pollution, which helps to achieve the goals of carbon peak and carbon neutrality.

[0086] The straw is reacted with pure oxygen (or oxygen-enriched air) under high temperature conditions to produce high-temperature synthesis gas containing gases such as CO, H2, and CO2. In this process, the use of high temperature and pure oxygen can effectively improve the gasification efficiency and gas quality. As agricultural waste, the large-scale use of straw helps reduce environmental pollution and convert it into renewable energy. The green electricity generated by renewable energy (such as solar energy, wind energy or tidal energy) drives the water electrolysis device to decompose water into hydrogen and oxygen, which are called green hydrogen and green oxygen respectively. The green hydrogen produced by electrolysis is directly introduced into the straw gasification system to reduce or replace the carbon emissions that may be generated in the traditional hydrogen production process. At the same time, green oxygen can be used in the high-temperature gasification process to improve the gasification efficiency. The excess green oxygen produced during the electrolysis process is stored under pressure for subsequent use in pure oxygen high-temperature gasification furnaces or as a raw material for pure oxygen combustion in gas boilers, further improving energy utilization efficiency. When the stored green oxygen is insufficient to meet demand, the self-contained oxygen production system is started to ensure the continuous and stable operation of the system.

[0087] In step ① of the present invention, "green oxygen enters the straw pure oxygen gasification furnace, undergoes gasification reaction, and obtains raw gas" can be achieved through the following three inventions: ZL201210251366.1 A method and equipment for self-generated gas from straw for electrolysis of hydrogen, ZL201310320648.2 A method for preparing gas by rolling and squeezing straw for electrolysis of hydrogen, and using foamed coal column particles instead of lump coal, and ZL201410576612.5 A method for preparing gas for power generation by electrolysis of hydrogen. The gasification reaction can also be effectively controlled by constructing multiple layers of materials (including slag layer, oxidation layer, reduction layer, and retorting layer from bottom to top), especially to prevent crossfire, and the effectiveness of this design has been verified.

[0088] In the straw gasifier, by constructing a multi-layer material layer (including slag layer, oxidation layer, reduction layer and distillation layer) more than ten meters thick, the gasification reaction process can be finely controlled. The main functions of these layers are as follows:

[0089] Oxidation layer: The straw undergoes a violent combustion reaction with oxygen, producing a large amount of heat and carbon dioxide. This heat provides the necessary energy for the subsequent reduction reaction and distillation process.

[0090] Reduction layer: Above the oxidation layer, the high temperature and oxygen-deficient environment promote the reduction reaction of carbon dioxide with the carbon in the straw to produce combustible gases such as carbon monoxide and hydrogen, which is the core part of the gasification process.

[0091] Retorting layer: Above the reduction layer, the temperature gradually decreases, but there is still enough heat to cause the straw to undergo pyrolysis reaction, further producing combustible gases, tar and other substances.

[0092] Conventional gasifiers will experience crossfire, that is, the flame at the bottom of the gasifier directly penetrates the material layer, reaches the upper part and causes combustion, which will lead to a decrease in gasification efficiency and even damage the equipment. This technology can effectively prevent the occurrence of crossfire by constructing a material layer of sufficient thickness:

[0093] First, the material layer of more than ten meters thick provides a huge resistance to the spread of flames. Even if there is a flame at the bottom, it is difficult to penetrate such a thick material layer to reach the upper part. Secondly, inside the material layer, as oxygen is gradually consumed, an oxygen-deficient or oxygen-free environment is formed. This further inhibits the spread of flames and the occurrence of combustion reactions.

[0094] The present invention combines straw gasification technology with water electrolysis hydrogen production technology, and cleverly introduces the straw gas power generation link, forming an innovative and efficient renewable energy green hydrogen production process route. This concept not only reduces the cost of hydrogen production, but also improves energy utilization efficiency, which is of great significance to promoting energy transformation and sustainable development. In the traditional straw gasification process, oxygen supply often relies on air separation or pure oxygen supply, which is costly. The present invention directly uses the oxygen produced by water electrolysis for straw gasification, which not only reduces the dependence on external oxygen sources, but also utilizes the byproduct oxygen produced in the water electrolysis process, thereby reducing the overall hydrogen production cost. The combustible gas (such as synthesis gas) produced in the straw gasification process can be used for power generation. This link not only recovers part of the energy, but also provides power support for water electrolysis hydrogen production, realizes multi-level utilization and self-sufficiency of energy, and further reduces the system's dependence on external electricity. Water electrolysis hydrogen production technology itself has a high energy efficiency conversion rate, and with the continuous advancement of technology, its cost is gradually decreasing. After combining with straw gasification technology, the overall energy efficiency can be further improved by optimizing system design and operating conditions. Since the fuel gas produced by straw gasification can be used for power generation, it provides a stable source of electricity for hydrogen production by electrolysis of water, thus solving the problem of unstable efficiency caused by power fluctuations in the process of hydrogen production by electrolysis of water.

[0095] The process route of the present invention uses renewable energy (straw, solar energy, wind energy or tidal energy, etc.) throughout the process, realizing a fully green production chain from raw materials to products, which meets the urgent global demand for clean energy and sustainable development. By reducing dependence on traditional fossil energy, the process helps reduce greenhouse gas emissions, combat climate change, and promote the construction of an environmentally friendly society.

[0096] The present invention adopts a method of coupling hydrogen electrolysis and straw pure oxygen gasification to produce hydrogen. Figure 1As shown, conventional oxygen production equipment is used to prepare air into oxygen through the oxygen production equipment, and oxygen and external steam are transported to the straw pure oxygen gasifier. After the straw raw material is gasified by the straw pure oxygen gasifier, fuel gas (CO, H2, CO2) is obtained. The fuel gas and external steam are subjected to carbon monoxide conversion treatment to obtain H2 and CO2. After H2 is purified by pressure swing adsorption, hydrogen is obtained, which is recovered, stored or utilized. On the other hand, after generating electricity using solar energy, wind energy or tidal energy, the obtained electric energy can be introduced into the (electrolyzer) electrolysis center through the line. The electrolyzer electrolyzes water to produce green oxygen and green hydrogen. The green oxygen enters the straw pure oxygen gasifier, undergoes gasification reaction, and obtains fuel gas; the green hydrogen can be directly recovered, stored or utilized.

[0097] Further, such as Figure 2 As shown, gas boiler equipment is added, and pure oxygen and fuel gas are used to burn the gas boiler to generate steam and naturally obtain CO2 after burning with pure oxygen. Part of the steam enters the straw pure oxygen gasification furnace, and part enters the carbon monoxide shift reaction; CO2 is separated again during the synthesis, and the two types of CO2 are recycled, stored or utilized. The fuel gas can be used to generate electricity directly, and the electricity obtained is used for oxygen production equipment or electrolyzers to achieve zero carbon emissions from the boiler.

[0098] The straw is mixed with O2+CO2 as a gasifier in a fixed bed gasifier to produce CO, H2, and CH4 with a content of 70-82%, and the gas production per ton of straw reaches 1100m 3 / t, oxygen consumption 180-275m 3 / t.

[0099] In order to avoid mixing with air and water vapor and improve the reduction efficiency of CO2, the present invention needs to keep the temperature of the gas discharged from the furnace mouth at about 130°C. This is because high temperature is conducive to the gasification reaction, but too high temperature may bring additional energy consumption and safety hazards. Therefore, by controlling the reaction conditions, such as the thickness of the reaction layer and the ratio of the gasifying agent, the appropriate furnace mouth temperature can be maintained while ensuring the gasification efficiency.

[0100] In order to achieve high-intensity (large flow) and high-efficiency gasification, it is necessary to use a particularly thick raw material layer and use CO2 and O2 as a mixed gasifying agent. The advantage of this mixed gasifying agent is that CO2 can replace traditional steam as a reducing agent, thereby improving the gasification efficiency. At the same time, since steam has a low cracking rate and absorbs a large amount of heat energy, the use of CO2 can reduce the loss of this part of heat energy and avoid the influence of steam on the wetting and expansion of the upper straw raw material in the furnace. In the process of thickening the raw material layer, special attention should be paid to prevent the appearance of trace oxygen and water vapor. This is because these impurities may destroy the stability of the raw material layer, resulting in interruption of the gasification process or decreased efficiency. Therefore, it is necessary to ensure the stable and continuous gasification of the raw material layer by adjusting the thickness of the reaction layer and the ratio of the gasifying agent, as well as strengthening the sealing and dehumidification measures. Regarding the thickness setting of the oxidation layer and the reduction layer in the original method, although it can meet the gasification requirements to a certain extent, it may be insufficient in the high-intensity and high-efficiency gasification process. Therefore, it is necessary to appropriately adjust the thickness of the reaction layer according to the actual situation, and combine the use of mixed gasifying agents to achieve better gasification effects. In summary, in the process of straw gasification using O2 and CO2 as gasifying agents at high temperature, it is necessary to pay attention to key factors such as controlling the furnace mouth temperature, adjusting the reaction layer thickness and the gasifying agent ratio, and preventing the appearance of trace oxygen and water vapor, so as to achieve high-intensity and high-efficiency gasification.

[0101] The straw described in the present invention is plant straw in a broad sense, such as crop straw, forest branches, plant stems, shells, skins, reeds, and grass leaves. The raw materials are hundreds of millions or even billions of tons each year, with abundant sources and huge annual output. They are renewable resources and can be supplied continuously.

[0102] The present invention divides the fixed bed gasifier into a lower slag layer, a middle oxidation layer and a reduction layer, and an upper dry distillation separation layer, and sets the thickness of the oxidation layer and the reduction layer to 1.5-4.5 times the furnace diameter, thereby effectively solving the problems of crossfire, low gasification intensity, and low reduction rate in the process of straw gasification. This design makes the gasification process more stable and efficient, and improves the gas production per ton of material and the gas quality. In addition, such a design directly constitutes an upper section with a particularly high and thick water jacket, which forms a full-height three-piece water jacket structure with the lower section and the middle section, greatly increasing the area of ​​the upper section water jacket, thereby more effectively absorbing low-temperature heat. After the upper section water jacket absorbs low-temperature heat over a large area, the water temperature can be raised to above 70°C. High-temperature water then enters the lower section and the middle section, effectively sealing and strictly insulating the gasification process of the gasifier, thereby generating more heat energy. This heat energy can be further converted into high-temperature hot water or saturated steam above 130°C, thereby improving energy utilization efficiency.

[0103] Taking the 3.6-meter diameter gasifier as an example, the gasifier is cleverly divided into three sections: the lower section is a 3-meter-high slag layer, the middle section is a 6-meter-high oxidation layer and reduction layer, and the upper section is 8 meters high (including a 4-meter separation space for the retort layer). This design cleverly solves the problem of fire flashing between the oxidation layer and the reduction layer in traditional gasifiers. By increasing the layer height to 6 meters and maintaining high-temperature gasification conditions of 1050-1300℃, the fire flashing phenomenon is effectively locked, significantly improving gasification efficiency and stability.

[0104] Using O2+CO2 as a gasifier, the gasification temperature is increased to 1050-1300℃, which significantly improves the gasification efficiency and reduction rate. High-temperature gasification also helps to reduce the generation of tar and other harmful substances and improve the cleanliness of the synthesis gas. The green hydrogen produced by electrolysis of water and the synthesis gas (green hydrogen) produced by gasification are coupled to produce high-value chemicals such as methane and methanol. This coupling reaction not only utilizes the cleanliness of electrolytic hydrogen, but also realizes efficient conversion and storage of energy through chemical reactions. The entire production process uses straw and other straw resources as raw materials, and maximizes the utilization of resources through steps such as gasification, electrolysis and coupling reactions. At the same time, by-products such as waste slag can also be further processed and utilized to form a closed-loop circular economy model.

[0105] Table 2: Furnace diameter, lower section height, middle section height, upper section height, and preferred data of straw pure oxygen gasification furnace:

[0106] Table 2 Parameters of straw pure oxygen gasifier

[0107]

[0108]

[0109] The straw pure oxygen gasifier of the present invention selects straw O2+CO2 as a gasifying agent. Under the condition that the gasification temperature reaches 1050-1300°C, the reduction rate of CO can be significantly improved. When the gasification temperature reaches 1050°C, the reduction rate of CO can reach more than 50%. When the gasification temperature exceeds 1200-1300°C, the reduction rate of CO can be further increased to about 70%. Due to the increase in the CO reduction rate at high temperature, the consumption of straw can be reduced by 10-15%. This means that at the same output, less straw raw material is required, which reduces the cost of raw materials. At the same time, the consumption of oxygen can also be significantly reduced by hundreds of cubic meters, which further reduces the production cost. The increase in the CO content in the raw gas (mainly composed of CO and H2) makes the amount of green hydrogen (electrolytic hydrogen) required relatively reduced in the subsequent synthesis of methane or methanol, thereby reducing the overall coupling cost. This high-temperature gasification method can reduce the price of raw gas by about 15%, improving the economy of the entire process.

[0110] After harvesting, the straw does not fall to the ground, but is directly stored and squeezed to extract the juice (such as sugar, etc.). This juice can be further processed and utilized (such as making sugar). The moisture content of the squeezed residue (slag) is controlled at ≤43%, in preparation for subsequent drying and gasification. The slag is transported to a high place by an extra-long belt, scattered into large hills, and dried in natural light and wind. After several to ten hours of drying, the moisture content of the slag is further reduced to 38-35%. The slag then enters the extruder for preliminary extrusion, and the temperature is generated by rolling friction, further reducing the moisture content to ≤33%. The semi-finished particles extruded continue to enter the second extruder for fine molding. The moisture content of the final particles is within ≤25%, which is suitable for high-temperature gasification in the gasifier.

[0111] Straw is directly stored after harvesting without being exposed to the ground, effectively avoiding energy loss and carbon dioxide emissions caused by long-term exposure to wind and sun. This method significantly reduces the weathering of straw during storage, retains the high volatile matter in the straw, and provides high-quality raw materials for the subsequent gasification process. The straw is pressed in time within two to three days after harvesting, further reducing the energy loss caused by long-term storage. During the pressing process, the juice in the straw is extracted for the production of by-products such as sugar boiling, while the residue is directly used in the subsequent gasification process. This efficient pressing process not only retains the high volatile matter in the straw, but also significantly reduces the storage cost and reduces the space occupied by more than 80%-90%.

[0112] After being squeezed, the residue climbs to a height of more than 20 meters through an extra-long belt and scatters into large hills. During this process, the moisture of the residue gradually dissipates under the action of natural light and wind, and the moisture content is reduced from the initial 43% to 38-35%. This natural drying method is not only environmentally friendly and energy-saving, but also further improves the dryness of the residue, which is conducive to the subsequent gasification process. Subsequently, the residue undergoes the first round of extrusion particle treatment. Under the action of rolling friction, the residue generates a certain temperature, which further promotes the evaporation of internal moisture and the retention of volatiles. This pretreatment method makes the residue more suitable for the green oxygen gasification process, improving the gasification efficiency and gas quality.

[0113] Example 1

[0114] A method for continuously preparing and supplying green hydrogen comprises the following steps:

[0115] ① After generating electricity using solar energy, wind energy or tidal energy, the resulting electricity is introduced into the electrolysis center through the line. The electrolysis center electrolyzes water to produce green oxygen and green hydrogen. The green oxygen enters the straw pure oxygen gasification furnace, undergoes a gasification reaction, and obtains raw gas; the raw gas includes CO, H2, CO2 and CH4;

[0116] ② The raw gas obtained in step ① is mixed with the green oxygen produced by the electrolysis center and then burned with pure oxygen in a gas boiler to produce steam and high-purity CO2, wherein the high-purity CO2 is input into the straw pure oxygen gasification furnace or recycled;

[0117] Alternatively, the raw gas obtained in step ① is used to generate electricity with an internal combustion engine to obtain electrical energy, which is then introduced into an electrolysis center to electrolyze water to produce green oxygen and green hydrogen, and enter the next cycle.

[0118] Furthermore, the hydrogen produced by the electrolytic hydrogen center and the raw gas obtained in step ① are pressed into a methane synthesis device for pressurized and high-temperature synthesis of methane, and the remaining CO2 in the synthesis is returned to the straw pure oxygen gasification furnace or recycled.

[0119] The gas production per ton of straw is about 1100m 3 The composition of the raw gas contained therein is shown in Table 3. The raw gas and electrolytic green hydrogen synthesize super energy CH4, and the final gas is obtained.

[0120] Table 3 Composition of raw gas and statistical values ​​of the amount of super-energy CH4 synthesized

[0121]

[0122] As shown in Table 3, the consumption of electrolytic green hydrogen is 550m 3 and 1100m 3 Raw gas synthesis green methane 451m 3 , plus 44m of straw methane 3 , a total of 495m3 of methane was produced 3 , around, and produces 165m of carbon dioxide at the same time 3 When using synthetic super energy CH4, the CO in the required raw gas does not change, and the reaction equation for synthesizing super energy CH4 with electrolytic green H2 is:

[0123]

[0124] Hydrogen is produced from the raw gas CO, H2, CO2, and CH4, and CO is converted with steam. Methane is produced by directly using existing CO+H2+hydrogen to synthesize methane, or CO and H2 are matched to convert part of CO to directly synthesize green methane. Excess CO2 is returned to the pure oxygen continuous gasification furnace or used to synthesize methanol and other green products.

[0125] Each ton of straw requires 180m3 of O2+CO2 gasification 3 Green oxygen output above 1100m 3 Gas, if 1 billion tons of straw is gasified, it will produce trillions of m 3 The energy of raw gas for green oxygen gasification is equivalent to 300 billion m 3 Natural gas energy.

[0126] Electrolytic oxygen and raw gas fired gas boiler: 240m 3 Raw gas matching 120m 3 Electrolytic oxygen burns out one ton of steam, and clean, high-purity carbon dioxide is recovered at the tail of the boiler after combustion. The fuel gas, oxygen, carbon dioxide recovery and gasification oxygen consumption per ton of steam are shown in Table 4.

[0127] Table 4

[0128]

[0129]

[0130] Example 2

[0131] A method for continuously preparing and supplying green hydrogen, such as Figure 3 As shown, the following steps are included:

[0132] Photovoltaic power and wind power (1) are used as clean energy and are introduced into the electrolysis center (2) through lines. In the electrolysis center (2), the introduced photovoltaic power and wind power are used to electrolyze water to produce green oxygen (11) and hydrogen (10); the green oxygen (11) enters the pure oxygen gasifier (3) and is gasified at high temperature together with the straw. During the gasification process, the straw is converted into raw gas containing CO, H2, straw CO2, CH4 and other components; the raw gas is pressed into the methane synthesis device (4) and is pressurized and catalytically synthesized with the hydrogen (10) produced by the electrolysis center to produce methane (5). The remaining straw CO2 (6) in the synthesis process is recovered as much as possible and sent back to the pure oxygen gasifier (3) for reuse, or additional supplementation is used to maintain the stable operation of the system.

[0133] In order to improve the utilization rate of straw CO2, the system introduces a green oxygen gas boiler (7). The CO, H2, straw CO2 and green oxygen (11) in the raw gas are sent to the boiler as fuel for combustion, producing straw CO2 (8) and steam (9) with higher purity. The straw CO2 (8) is sent to the excess gasification furnace of the methanol synthesis unit. The steam (9) generated by the green oxygen gas boiler (7) during the combustion process can be used for other process steps, such as purification and conversion of raw gas and heating of the gasification furnace. In addition, the entire system is also equipped with an internal combustion engine power generation device (13) to generate electricity using excess heat or electricity to achieve energy self-sufficiency. Before entering the methane synthesis unit, the raw gas needs to be processed by a purification system (12) to remove impurities and harmful substances therein to ensure the quality and efficiency of the synthesized methane. The purification technology and equipment are as follows: the gas produced by gasification is sent to the dust collector through the gas outlet pipe, and after dust removal, it enters the heat exchanger (for cooling), enters the air cooler (for further cooling), enters the first and second level electric coke capture devices, and then enters the oil-water separator, and then sulfur and nitrogen oxides are removed by activated carbon, and then pressurized into the synthesis system. The equipment and devices are common in coal gas.

[0134] The whole process is cleverly designed, and each molecule is cleverly combined according to its valence to achieve a perfect molecular balance between electrolytic hydrogen, oxygen and gasified straw CO, straw H2 and straw CO2. By squeezing out and eating up everything, the efficiency of energy and resource utilization is maximized.

[0135] Furthermore, if Figure 4 and Figure 5 As shown, the straw pure oxygen gasification furnace comprises a furnace wall (14), and the outer periphery of the furnace wall (14) is sequentially mounted with a first water jacket (15), a second water jacket (16) and a third water jacket (17) from bottom to top. The third water jacket (17) has a low-temperature water outlet (18) at the top, a normal-temperature water inlet (19) at the bottom, a low-temperature water inlet (20) at the bottom of the first water jacket (15), a medium-temperature water outlet (21) at the top of the first water jacket (15), a medium-temperature water inlet (22) at the bottom of the second water jacket (16), and a high-temperature medium outlet (23) at the top of the second water jacket (16).

[0136] The normal temperature water inlet (19) is connected to a water supply pipeline (24); a low temperature water pipeline (25) is connected between the low temperature water outlet (18) and the low temperature water inlet (20); a medium temperature water pipeline (26) is connected between the medium temperature water outlet (21) and the medium temperature water inlet (22); a steam discharge pipeline (28) is installed on the high temperature medium discharge outlet (23); and a raw gas conduit (27) connected to the furnace is installed on the furnace wall (14).

[0137] The first water jacket (15), the second water jacket (16) and the third water jacket (17) are sequentially arranged on the gasifier to adapt to the heat exchange temperatures at different heights on the gasifier, so as to realize the gradual heating and heat exchange of the heat exchange medium. The heat exchange medium will move upward in the water jacket after the heat exchange and temperature rise. In the flow circulation process of the heat exchange medium gradually rising in temperature, it will enter from the bottom of the water jacket. After sufficient heat exchange, it will flow out from the top of the water jacket and enter the next water jacket. The first water jacket (15) corresponds to medium temperature heat exchange, the second water jacket (16) corresponds to high temperature heat exchange, and the third water jacket (17) corresponds to low temperature heat exchange. The heat exchange medium is heated in the third water jacket (17), the first water jacket (15) and the second water jacket (16) in turn.

[0138] During the cyclic heating process, the third water jacket (17) at the top has the lowest temperature, and the second water jacket (16) at the middle has the highest temperature. Normal temperature water first enters the bottom of the third water jacket (17) from the water supply pipeline (24), and after preliminary heat exchange and heating, is discharged from the low temperature water outlet (18) into the low temperature water pipeline (25), and enters the first water jacket (15) through the low temperature water inlet (20). After secondary heating and heat exchange, it is discharged from the medium temperature water outlet (21) at the top of the first water jacket (15) into the medium temperature water pipeline (26), and enters the second water jacket (16) through the medium temperature water inlet (22). After final heating, it is discharged from the high temperature medium outlet (23), thereby achieving high-efficiency comprehensive heat exchange.

[0139] The steam exhaust pipeline (28) can produce steam, and the raw gas conduit (27) can produce raw gas. The steam exhaust pipeline (28) is connected to the carbon monoxide conversion reaction container (29). A three-way pipe (30) is installed at the gas outlet of the raw gas conduit (27). The two outlets of the three-way pipe (30) are respectively connected to the carbon monoxide conversion reaction container (29) and the gas boiler (31). On the one hand, the raw gas is mixed with steam and converted into H2 and CO2 through carbon monoxide. On the other hand, the raw gas is allowed to enter the gas boiler (31) for combustion, and water is heated to produce steam and CO2. The obtained steam is used for carbon monoxide conversion. The oxygen storage device of the electrolysis center is connected to the inner cavity of the furnace wall (14) through a pipeline, and can provide the necessary oxygen during the combustion of the bio-medium in the gasifier.

[0140] Furthermore, a water level gauge (34) is installed inside the second water jacket (16). The water level gauge (34) can monitor the water level inside the second water jacket (16) in real time. After the heat exchange medium is heated to form steam, the internal water level will decrease. At this time, the water level gauge (34) receives a signal and subsequently controls the water replenishment pipeline (24) to replenish the heat exchange medium into each water jacket. An ash pan slag discharge system (35) is installed at the bottom of the furnace wall (14). A connected feeder (36) is provided at the top of the furnace wall (14). The feeder (36) is used to put straw and other fuels into the gasifier. A denitrification feeder (37) is installed on the upper part of the feeder (36). When feeding, the denitrification agent follows the feeding. When the feeding stops, the denitrification agent is stopped synchronously.

[0141] A material detection layer stem (38) is installed on the furnace wall (14) on one side of the feeder (36). The material detection layer stem (38) can detect the amount of straw fuel filled in the gasifier so as to supplement the fuel or perform subsequent combustion operations. A raw gas duct (27) is installed on the furnace wall (14) on the other side of the feeder (36) for discharging the fuel gas in the gasifier.

[0142] Furthermore, a bypass branch pipe (32) is installed on the three-way pipe (30), and the bypass branch pipe (32) is connected to the gas inlet of the internal combustion engine (33) to realize the combustion and power generation operation of the raw gas.

[0143] A method for preparing green hydrogen supply by continuous pure oxygen gasification of straw, wherein the continuous pure oxygen gasification mechanism of straw is divided into two or three stages of fixed bed high temperature gasification furnace; the middle stage is set up with a high temperature of 900-1250℃ and effective characteristics of straw (C5+H 10 +O5) components are firmly controlled in the middle furnace of 1.5-4.5 times the furnace diameter. The upper section is 1.5-4.5 times the furnace diameter. Half of the straw dry distillation raw materials completely block the flame and cover, filter, heavy dust, and coarse tar. The other half is space through the end surface area to make the gas rise speed stable at 0.1-0.3m / s, so that heavy dust and coarse tar cannot sink with the gas flow and be covered by the top material and enter the reduction layer.

[0144] The lower section has a slag layer 0.4-1.5 times thick as the furnace diameter. The slag layer 0.4-1.5 times thick as the furnace diameter delays and retains the time for full oxidation and reduction sinking. At the same time, the gasifier is fully heat-exchanged to assist oxygenation and high temperature reduction to reduce the oxygen content of the gas to ≤0.9%. The raw gas CO, H2, CH4, and CO2 produced contain CO+H2=70-82%, CO2=15-17%. The economic value of the raw gas CO2 produced by pure oxygen gasification doubles for every 5% reduction. The key is to achieve a gasification intensity of 300-900m 3 / m 2 The straw is continuously gasified with pure oxygen for thousands or tens of thousands of hours every day, ensuring that hundreds or thousands of tons of straw are digested and consumed every day, becoming an inexhaustible green energy source on a large scale and industrial scale.

[0145] In summary, in a method for continuous preparation and supply of green hydrogen, the upper section, the middle section and the lower section can be combined into one, or the upper section, the lower section and the middle section can be combined into one, but the total length is greater than 1.5-6 times the diameter.

Claims

1. A method for continuous preparation and supply of green hydrogen, characterized in that: The following steps are involved: Install solar energy, wind energy or tidal energy power generation equipment; straw pure oxygen gasification furnace and gas boiler; When solar energy, wind energy or tidal energy is sufficient to generate electricity, the electricity generated by solar energy, wind energy or tidal energy is introduced into the electrolysis center through the line, and the electricity is used to electrolyze water using electrolysis equipment in the electrolysis center to produce oxygen and hydrogen. The hydrogen is used for external supply, and the oxygen is stored for standby use; When solar energy, wind energy or tidal energy is not enough to generate electricity, a portion of the stored oxygen is continuously introduced into the straw pure oxygen gasifier filled with straw, so that the straw in the straw pure oxygen gasifier burns in a pure oxygen environment to generate a gasification reaction to obtain raw gas; The raw gas includes CO, H2, CO2 and CH4; Take a part of the raw gas and mix it with the steam produced by the gas boiler, convert it into H2 and CO2 through carbon monoxide conversion, and purify the H2 before supplying it externally; The remaining raw gas is mixed with another part of the stored oxygen and burned in a gas boiler to heat water to produce steam and CO2. The resulting steam is used for carbon monoxide conversion. The CO2 obtained after carbon monoxide conversion and the CO2 produced by the gas boiler are recovered for external supply or input into the straw pure oxygen gasification furnace for use as a reducing agent.

2. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: When the amount of raw gas required by the user is less than the raw gas produced, the excess raw gas is used to generate electricity through an internal combustion engine or a gas turbine to obtain raw gas electricity, and the obtained raw gas electricity is stored or introduced into the electrolysis center.

3. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: The straw pure oxygen gasification furnace is a two-stage or three-stage fixed bed high-temperature gasification furnace with a gasification temperature of 900-1250°C. When selecting the furnace diameter, the height of the lower slag layer is 0.4-1.5 times the furnace diameter, the height of the middle redox layer is 1.5-4.5 times the furnace diameter, the height of the upper dry distillation material layer is 1.5-4.5 times the furnace diameter, and the gasification intensity is 300-900m 3 / m 2 , the total height is ≥1.5 times the furnace diameter; Pure oxygen produced by water electrolysis and CO2 or a small amount of steam produced by straw gasification are used as mixed high-temperature gasifying agents.

4. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: During high-temperature gasification of the straw pure oxygen gasifier, the temperature of the gas outlet from the furnace is between 75 and 130°C, ensuring that there is no mixing of air and water vapor in the straw pure oxygen gasifier, and high-temperature gasification increases the reduction of CO2.

5. The method for continuous preparation and supply of green hydrogen according to claim 3, characterized in that: The three-stage fixed-bed high-temperature gasification furnace is divided into a lower slag layer, a middle oxidation-reduction layer and an upper dry distillation separation layer.

6. A method for continuous preparation and supply of green hydrogen according to claim 5, characterized in that: The thickness of the upper dry distillation separation layer is 1 to 4.5 times the furnace diameter.

7. A method for continuous preparation and supply of green hydrogen according to claim 5, characterized in that; The upper section, middle section and lower section can be combined into one, or combined into one, but the total height or thickness is 1.5-6 times greater than the diameter. The gasification agent can be oxygen-enriched or a mixture of air and steam to produce fuel gas for heating or as green energy.

8. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: The straw pure oxygen gasification furnace comprises a furnace wall (14), and the outer periphery of the furnace wall (14) is sequentially mounted with a first water jacket (15), a second water jacket (16) and a third water jacket (17) from bottom to top, wherein the upper part of the third water jacket (17) is provided with a low-temperature water outlet (18), the lower part of the third water jacket (17) is provided with a normal-temperature water inlet (19), the lower part of the first water jacket (15) is provided with a low-temperature water inlet (20), the upper part of the first water jacket (15) is provided with a medium-temperature water outlet (21), the lower part of the second water jacket (16) is provided with a medium-temperature water inlet (22), the upper part of the second water jacket (16) is provided with a high-temperature medium discharge outlet (23), the normal-temperature water inlet (19) is connected to a water supply pipeline (24), the low-temperature water outlet (18) and the low-temperature water inlet (20) are connected to each other. A low-temperature water pipeline (25) is connected between the medium-temperature water outlet (21) and the medium-temperature water inlet (22). A medium-temperature water pipeline (26) is connected between the medium-temperature water outlet (21) and the medium-temperature water inlet (22). A steam exhaust pipeline (28) is installed on the high-temperature medium outlet (23). A raw gas conduit (27) connected to the furnace is installed on the furnace wall (14). The steam exhaust pipeline (28) can produce steam, and the raw gas conduit (27) can produce raw gas. The steam exhaust pipeline (28) is connected to the carbon monoxide conversion reaction container (29). A three-way pipe (30) is installed at the gas outlet position of the raw gas conduit (27). The two outlets of the three-way pipe (30) are respectively connected to the carbon monoxide conversion reaction container (29) and the gas boiler (31). The oxygen storage device of the electrolysis center is connected to the inner cavity of the furnace wall (14) through a pipeline.

9. A method for continuous preparation and supply of green hydrogen according to claim 8, characterized in that: A bypass branch pipe (32) is installed on the three-way pipe (30), and the bypass branch pipe (32) is connected to the fuel gas inlet of the internal combustion engine (33).

10. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: The mechanism of continuous gasification of straw with pure oxygen is divided into two or three sections of fixed-bed high-temperature gasification furnace settings; the middle section firmly controls the 2.5-3.5 long flame produced by the gasification temperature of 900-1250℃ and the straw components in the middle furnace chamber which is 1.5-4.5 times thick or high; the upper section has another 1.5-4.5 times thick or high furnace diameter, half of which is straw distillation raw material to completely block the flame and cover and filter heavy dust and crude tar, and the other half is space through the end surface area to make the rising speed of the generated gas stable at 0.1-0.3m / s, so that the heavy dust and crude tar mass effect cannot sink with the gas flow and be covered by the top material and enter the reduction layer, thereby reducing the mixing of dust and crude tar into the fuel gas.

11. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: The bottom of the straw pure oxygen gasification furnace is set with a slag layer 0.4-1.5 times the furnace diameter. The slag layer 0.4-1.5 times the furnace diameter delays, retains oxidation, and reduces the sinking time. At the same time, the gasification agent is fully heat-exchanged to assist oxygen gasification. High temperature increases reduction and reduces the oxygen content of the gas to ≤0.9%. The raw gas CO, H2, CH4, and CO2 produced contain CO+H2=70-82%, and CO2=15-17%. The economic value of the raw gas CO2 produced by pure oxygen gasification doubles for every 5% reduction. The key is to achieve a gasification intensity of 300-900m 3 / m 2 The straw is continuously gasified with pure oxygen for thousands or tens of thousands of hours every day, ensuring that hundreds or thousands of tons of straw are digested and consumed every day, becoming an inexhaustible green energy source on a large scale and industrial scale.

12. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: CO2 reducing agent; CO2 and O2 are mixed into oxygen in the following ratio, CO2 = 20%-50%, O2 = 50%-80%, and fully mixed to form a straw pure oxygen reducing agent; when gasifying the straw, it first goes from the lower part of the slag layer to the upper part, from the lower low temperature to the upper high temperature for heat exchange, reaches the upper part of the slag layer to form a high temperature, enters the oxidation layer to react violently and releases ultra-high temperature gas of 900-1300°C, and then enters the reduction layer; the high-temperature CO2 entering the reduction layer collides with the straw C in the reduction layer in the furnace to generate CO2, and the O2 is cracked by the high temperature of 900-1300°C to remove one O to capture C and generate CO; that is, it is reduced to generate 2CO, and at a high temperature of 1050°C, CO2 can reduce CO to about 50%, that is, it is strongly captured by the ultra-high temperature CO2 of 900-1300°C to reduce CO.

13. The method for continuous preparation and supply of green hydrogen according to claim 1, characterized in that: In order to achieve better straw gasification, a small amount of high-temperature steam is mixed as a gasifying agent when CO2 is insufficient. That is to ensure that the straw particles in the upper layer of more than ten meters in the furnace are not soaked by excessive water vapor for a long time and expand and bloom, and cannot form columnar particles to form honeycombs. Therefore, the slag layer is 0.4-1.5 times the furnace diameter; in order to control and lock the flame length, the oxidation and reduction layers are 1.5-4.5 times the furnace diameter; in order to prevent the generation of gasification dust and crude tar flowing with the gas; the dry distillation and space layers are also 1.5-4.5 times the furnace diameter to effectively settle in the covered material layer.

14. A method for continuously preparing methane from green hydrogen, characterized in that: The following steps are involved: After generating electricity using solar energy, wind energy or tidal energy, the resulting electricity is introduced into the electrolysis center through lines. The electrolysis center electrolyzes water to produce oxygen and hydrogen, of which the oxygen enters the straw pure oxygen gasifier to undergo a gasification reaction to obtain raw gas; the raw gas includes CO, H2, CO2 and CH4; the hydrogen produced by the electrolysis center and the raw gas obtained from the straw pure oxygen gasifier are pressed into a methane synthesis device for pressurized and high-temperature synthesis of methane, and the remaining CO2 in the synthesis is returned to the straw pure oxygen gasifier or recycled.

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