A zero-carbon emission cement production device and method based on hydrogen energy utilization

Abstract

This application discloses a zero-carbon emission cement production device and method based on hydrogen energy utilization. The production device includes: a hydrogen production system, a fuel cell system, a waste heat recovery system, a cement clinker calcination decomposition furnace system, a cement clinker calcination rotary kiln system, a grinding system, and a methanol synthesis system. This application uses hydrogen to partially replace the kiln fuel, which can achieve carbon emission reduction with minimal changes to the existing cement production line technology and at a relatively low modification cost. Addressing the high energy consumption and high carbon emissions in the cement industry, this application optimizes the material and energy flow throughout the entire cement production process, achieving the recycling of materials and the cascade utilization of energy, ensuring the low-carbon and environmentally friendly nature of the entire production method.

Description

Technical Field

[0001] This application relates to a zero-carbon emission cement production device and method based on hydrogen energy utilization, belonging to the field of cement production technology. Background Technology

[0002] Carbon dioxide emissions are directly related to the type of energy resources, the way they are used, and the total amount used. In 2020, carbon emissions from energy production and the industrial sector accounted for nearly 80% of total emissions.

[0003] In 2020, my country's cement production reached approximately 2.4 billion tons, accounting for 53% of the world's total cement production. It is projected that my country's cement production will decrease to 1.8 billion tons by 2030, but there will still be a demand of approximately 900 million tons by 2060. As a major building material for human society, the cement industry plays a vital role in supporting the rapid development of the national economy. However, its high carbon emissions necessitate a transformation towards low-carbon, green, and environmentally friendly practices.

[0004] The cement production process can be divided into three main stages: raw meal grinding, clinker calcination, and cement preparation. The energy consumption mainly includes electricity and heat. 90% of the CO2 emissions from cement production enterprises come from clinker production (fuel combustion and chemical reactions between raw materials), while the remaining 10% comes from the raw meal grinding and cement preparation stages.

[0005] In 2020, my country's cement production emitted approximately 1.4 billion tons of CO2, accounting for about 12.7% of the country's total emissions. Analyzing current cement production processes, indirect emissions from electricity use and direct emissions from coal combustion account for about 40% of total cement production emissions, while process emissions from raw materials such as calcium carbonate account for about 60%. The cement industry's carbon emissions are primarily process emissions, making deep decarbonization difficult to achieve through electrification; therefore, low-carbon development must be achieved through technological innovation.

[0006] Based on the decarbonization problem in the cement production process, this application aims to provide an optimized process solution based on the existing cement system technology. Summary of the Invention

[0007] According to one aspect of this application, a zero-carbon emission cement production device based on hydrogen energy utilization is provided, the zero-carbon emission cement production device comprising: a hydrogen production system, a cement clinker calcination decomposition furnace system, a cement clinker calcination rotary kiln system, and a grinding system;

[0008] The cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system are respectively connected to the hydrogen production system;

[0009] The cement clinker calcination decomposition furnace system is connected to the cement clinker calcination rotary kiln system, the cement clinker calcination rotary kiln system is connected to the grinding system, and the grinding system is connected to the cement clinker calcination decomposition furnace system.

[0010] The feed fuel of the cement clinker calcination decomposition furnace system includes hydrogen and pulverized coal, with hydrogen accounting for 5-30% of the mass of the feed fuel.

[0011] Optionally, the hydrogen content of the feed fuel is selected from any value of 5%, 8%, 10%, 15%, 20%, 25%, 30% or a range between any two of the above.

[0012] Optionally, the hydrogen production system provides hydrogen to the cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system.

[0013] Optionally, the feedstock for the hydrogen production system is methanol.

[0014] Optionally, the raw material for the hydrogen production system is methanol; the hydrogen produced can be supplied to, but is not limited to, cement clinker calcination rotary kiln systems, cement clinker calcination decomposition furnace systems, and fuel cell systems.

[0015] Optionally, the zero-carbon emission cement production unit further includes a methanol synthesis system, which is used to capture water and carbon dioxide generated by the cement clinker calcination decomposition furnace system, the grinding system, and the cement clinker calcination rotary kiln system.

[0016] Optionally, the oxygen generated by the methanol synthesis system is used to promote combustion in the cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system.

[0017] Optionally, the methanol synthesis system can recapture the water and carbon dioxide generated in processes such as the cement clinker calcination decomposition furnace system, grinding system, and cement clinker calcination rotary kiln system, and synthesize methanol feedstock, which is then supplied to the hydrogen production system for further hydrogen production. Oxygen is also generated during the synthesis process, which can be fed into the cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system to improve combustion.

[0018] Optionally, the zero-carbon emission cement production unit further includes a waste heat recovery system for recovering the generated waste heat.

[0019] Optionally, the waste heat recovery system recovers the waste heat generated by the cement clinker calcination decomposition furnace system to provide the required heat for the hydrogen production system.

[0020] Optionally, the waste heat recovery system can recover waste heat from other systems (including but not limited to cement clinker calcination decomposition furnace systems) and supply it to devices that require heat absorption operation (including but not limited to hydrogen production systems).

[0021] Optionally, the zero-carbon emission cement production device further includes a fuel cell system that powers the grinding system, and the hydrogen required by the fuel cell system is obtained from a hydrogen production system.

[0022] Optionally, the fuel cell system powers devices involved in the production process, including but not limited to grinding systems.

[0023] Optionally, the grinding system is used to grind coal powder, raw materials, and clinker into fine powder.

[0024] Optionally, the grinding system includes, but is not limited to, the following control units: raw material mill or cement mill, electrostatic precipitator, fan, exhaust gas treatment (humidification tower), etc., for grinding coal powder, raw materials or clinker calcined from the rotary kiln system to a certain fineness.

[0025] Optionally, the clinker is generated by calcination in the cement clinker rotary kiln system.

[0026] Optionally, the cement clinker calcination and decomposition furnace system includes, but is not limited to, the following control units: cyclone separator, heat exchange pipes, decomposition furnace, rotary kiln, cooler, fuel injection device, etc. The injected fuel includes currently used conventional fuels (pulverized coal or other alternative fuels) and hydrogen. By coupling the exothermic process of the fuel with the endothermic process of carbonate decomposition in the raw meal, the decomposition rate of the raw meal entering the kiln is increased to over 90%.

[0027] Optionally, the cement clinker calcination rotary kiln system includes, but is not limited to, the following control units: cylinder, support device, support device with thrust rollers, transmission device, movable kiln head, kiln tail sealing device, and combustion device. The combustion device is fed with currently used conventional fuels (pulverized coal or other alternative fuels) and hydrogen. After the material enters the rotary kiln system from the clinker calcination decomposition furnace system, due to the cylinder rotating at a certain speed and with a certain inclination, the material gradually moves from the kiln tail to the kiln head.

[0028] According to another aspect of this application, a zero-carbon emission cement production method based on hydrogen energy utilization is provided, the production method comprising the following steps:

[0029] (1) Pulverized coal and cement raw materials are fed into a zero-carbon emission cement production device, crushed by a grinding system, and then decomposed by a cement clinker calcination decomposition furnace system to obtain precast cement clinker.

[0030] (2) The obtained precast cement clinker is calcined with hydrogen in a cement clinker calcination rotary kiln system to obtain cement clinker.

[0031] (3) The obtained cement clinker is crushed by a grinding system to obtain cement;

[0032] The zero-carbon emission cement production equipment is selected from the zero-carbon emission cement production equipment described above.

[0033] In this application, the zero-carbon emission cement production method includes: pulverized coal and cement raw meal are crushed and homogenized by a grinding system and then sent to a cement clinker calciner decomposition system for further processing.

[0034] The processed raw materials are fed into the cement clinker calcination and decomposition furnace system to perform preliminary decomposition.

[0035] The cement clinker calcination rotary kiln system further calcines the product of the cement clinker calcination decomposition furnace system to obtain cement clinker, which is then sent to the grinding system for clinker grinding.

[0036] The energy input for the above-mentioned grinding system is provided by a fuel cell.

[0037] The energy input of the cement clinker calcination decomposition furnace system is provided by the combustion of hydrogen and pulverized coal (and alternative fuels).

[0038] The hydrogen required by the aforementioned fuel cell, cement clinker calcination decomposition furnace system, and cement clinker calcination furnace system is provided by a hydrogen production system, and the raw material for hydrogen production is methanol.

[0039] The above hydrogen production reaction formula is: CH3OH + H2O → CO2 + 3H2.

[0040] The heat of reaction in the aforementioned hydrogen production system comes from the thermal energy recovered by the waste heat recovery system from the cement clinker calcination and decomposition furnace system.

[0041] The methanol synthesis system recovers water and CO2 generated from the grinding system, cement clinker calcination decomposition furnace system, and cement clinker calcination rotary kiln system and resynthesizes methanol. The reaction formula is: 2CO2+4H2O→2CH3OH+3O2.

[0042] The methanol produced by the methanol synthesis system is supplied to the hydrogen production system for further hydrogen production; the oxygen produced is sent to the cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system.

[0043] This application uses hydrogen to partially replace kiln fuel, which can achieve effective carbon emission reduction with minimal changes to the existing cement production line technology and at a relatively low modification cost. Addressing the issues of high energy consumption and high carbon emissions in the cement industry, this application optimizes the material and energy flow throughout the entire cement production process, achieving the recycling of materials and the cascade utilization of energy, thus ensuring the low-carbon and environmentally friendly nature of the entire production method.

[0044] The beneficial effects that this application can produce include:

[0045] 1) This application uses hydrogen as an alternative energy source in the cement production process, which has virtually no significant impact on the processes and equipment of the existing more than 1,600 cement production lines. At the same time, it can significantly reduce the generation and emission of carbon dioxide and other harmful components during the production process, which is in line with the energy transformation route with the development direction of "low carbonization, carbon-free, and low pollution". It can effectively achieve carbon emission reduction at a relatively low transformation cost.

[0046] 2) This application improves the combustion process of solid fuel by adsorbing hydrogen into it, which can increase the utilization rate of alternative fuels, including low-quality fuels, thereby reducing carbon emissions per unit of clinker and unit production costs. Furthermore, hydrogen is produced on demand, eliminating the need for storage tanks, thus reducing transportation and storage costs and risks.

[0047] 3) All carbon dioxide and water generated during the production process of this application are captured, recovered, and reprocessed into methanol. This not only ensures that the methanol is reused in the hydrogen production system, but also supplies oxygen, another byproduct, to the decomposition system of the cement clinker calciner and the rotary kiln system of the cement clinker to improve combustion. At the same time, the waste heat generated during the process can be used for the hydrogen production reaction through the recovery system, realizing the recycling of materials and the cascade use of energy.

[0048] 4) In the cement production process provided in this application, the hydrogen production system provides hydrogen to both the cement clinker calcination rotary kiln system and the cement clinker calcination decomposition furnace system, replacing a portion of the pulverized coal combustion. The waste gas generated during cement production is purified and separated into flue gas and condensate. The flue gas is further separated and enriched with carbon dioxide to obtain a higher concentration of carbon dioxide. This carbon dioxide, combined with the condensate obtained from the water-gas separation, is then reacted in the methanol synthesis system to generate methanol, which is then reused by the hydrogen production system. Simultaneously, the methanol synthesis system generates oxygen for use in both the cement clinker calcination rotary kiln system and the cement clinker calcination decomposition furnace system, thereby improving the combustion characteristics of the fuel.

[0049] After the renovation, the cement plant can increase the use of alternative fuels by 21%, increase clinker production by 5%, and increase strength by 3.5 MPa. Moreover, the entire process has no CO2 emissions, achieving a "zero-carbon" effect. Attached Figure Description

[0050] Figure 1This is a schematic diagram of the zero-carbon emission cement production device for this application.

[0051] Figure 2 This is a schematic diagram of the material flow in zero-carbon emission cement production according to Embodiment 1 of this application. Detailed Implementation

[0052] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0053] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0054] Example 1

[0055] like Figure 1 The zero-carbon emission cement production unit shown has a hydrogen production system that uses methanol as feedstock to produce hydrogen, which is then supplied to the fuel cell system, the cement clinker calcination furnace system, and the cement clinker calcination rotary kiln system. These systems, along with the grinding system, are connected to a methanol synthesis system. The CO2 and water produced are recovered and resynthesized into methanol in the methanol synthesis system, providing feedstock for the hydrogen production system and ensuring recycling. The grinding system is connected to the cement clinker calcination furnace system, which in turn is connected to the cement clinker calcination rotary kiln system, which is in turn connected to the grinding system. The ground feedstock is then fed into the cement clinker calcination furnace system. The energy input for the grinding system is provided by the fuel cell system. A waste heat recovery system is connected to the cement clinker calcination furnace system to recover waste heat from the furnace, providing heat for the hydrogen production system.

[0056] Example 2

[0057] Taking the modification of a cement clinker kiln with an annual output of 2 million tons to establish a supporting hydrogen production system as an example. Before the modification, the main fuel of this equipment was pulverized coal, and the hydrogen substitution rate was approximately 12%. Hydrogen inlets and oxygen inlets were added to the rotary kiln and decomposer, respectively. The material flow is as follows... Figure 2 As shown.

[0058] In the cement production process, the hydrogen production system provides hydrogen to both the cement clinker calcination rotary kiln system and the cement clinker calcination decomposition furnace system, replacing a portion of the pulverized coal combustion. Waste gas generated during cement production is purified and separated into flue gas and condensate. The flue gas is further separated and enriched with carbon dioxide to obtain a higher concentration of carbon dioxide. This carbon dioxide, combined with the condensate obtained from the water-gas separation, is then reacted in the methanol synthesis system to produce methanol, which is then reused by the hydrogen production system. Simultaneously, the methanol synthesis system generates oxygen for use in the cement clinker calcination rotary kiln system and the cement clinker calcination decomposition furnace system, thereby improving the combustion characteristics of the fuel.

[0059] After the renovation, the cement plant can increase the use of alternative fuels by 21%, increase clinker production by 5%, increase strength by 3.5 MPa, and the entire process has no CO2 emissions.

[0060] Example 3

[0061] like Figure 2 As shown, the process equipment of a cement clinker kiln with a daily output of 100 tons was modified, and a supporting hydrogen production system, fuel cell system and waste heat recovery system were established.

[0062] In the cement production process, the hydrogen production system provides hydrogen to the fuel cell system, which in turn provides electrical energy to the grinding system to crush the raw materials before feeding them into the decomposition furnace system. The waste heat from the decomposition furnace system is recovered and supplied to the hydrogen production system for further hydrogen production.

[0063] After the renovation, the cement plant's heat loss was reduced by 30%, and the electricity loss per ton of clinker was reduced by 2 kWh.

[0064] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A zero-carbon emission cement production device based on hydrogen energy utilization, characterized in that, The zero-carbon emission cement production unit includes: a hydrogen production system, a cement clinker calcination decomposition furnace system, a cement clinker calcination rotary kiln system, and a grinding system; The cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system are respectively connected to the hydrogen production system; The cement clinker calcination decomposition furnace system is connected to the cement clinker calcination rotary kiln system, the cement clinker calcination rotary kiln system is connected to the grinding system, and the grinding system is connected to the cement clinker calcination decomposition furnace system. The feed fuel of the cement clinker calcination decomposition furnace system includes hydrogen and pulverized coal, with hydrogen accounting for 5-30% of the mass of the feed fuel; the raw material of the hydrogen production system is methanol. The zero-carbon emission cement production unit also includes a methanol synthesis system. The oxygen generated by the methanol synthesis system is used to promote combustion in the cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system. The carbon dioxide, the raw material for the methanol synthesis system, comes from the zero-carbon emission cement production unit.

2. The zero-carbon emission cement production device according to claim 1, characterized in that, The hydrogen production system provides hydrogen to the cement clinker calcination decomposition furnace system and the cement clinker calcination rotary kiln system.

3. The zero-carbon emission cement production device according to claim 1, characterized in that, The methanol synthesis system is used to capture water and carbon dioxide generated by the cement clinker calcination decomposition furnace system, the grinding system, and the cement clinker calcination rotary kiln system.

4. The zero-carbon emission cement production device according to claim 1, characterized in that, The zero-carbon emission cement production unit also includes a waste heat recovery system, which is used to recover the waste heat generated.

5. The zero-carbon emission cement production device according to claim 4, characterized in that, The waste heat recovery system recovers the waste heat generated by the cement clinker calcination and decomposition furnace system to provide the heat required for the hydrogen production system.

6. The zero-carbon emission cement production device according to claim 1, characterized in that, The zero-carbon emission cement production unit also includes a fuel cell system, which powers the grinding system, and the hydrogen required by the fuel cell system comes from the hydrogen production system.

7. The zero-carbon emission cement production device according to claim 1, characterized in that, The grinding system is used to grind coal powder, raw materials, and clinker into fine powder.

8. The zero-carbon emission cement production device according to claim 7, characterized in that, The clinker is generated by calcination in the cement clinker calcination rotary kiln system.

9. A zero-carbon emission cement production method based on hydrogen energy utilization, characterized in that, The production method includes the following steps: (1) Pulverized coal and cement raw materials are fed into a zero-carbon emission cement production device, crushed by a grinding system, and then decomposed by a cement clinker calcination decomposition furnace system to obtain precast cement clinker. (2) The obtained precast cement clinker is calcined with hydrogen in a cement clinker calcination rotary kiln system to obtain cement clinker; (3) The obtained cement clinker is crushed by a grinding system to obtain cement; The zero-carbon emission cement production device is selected from the zero-carbon emission cement production device according to any one of claims 1 to 8.

Images