1. Atmospheric fixed bed intermittent anthracite (or coke) gasification technology
At present, one of the coal gasification technologies mainly used in my country's nitrogen fertilizer industry is characterized by the use of normal pressure fixed bed air and intermittent steam production. The raw materials are required to be 25-75mm lump anthracite or coke. The utilization rate of the raw materials entering the factory is low, the unit consumption is high, the operation is complicated, the gas production per furnace is low, and the blowing and releasing of air cause serious atmospheric pollution. It is a process that will be gradually phased out.
2. Atmospheric fixed bed anthracite (or coke) oxygen-enriched continuous gasification technology
Its characteristics are that it uses rich oxygen as the gasification agent, continuous gasification, and the raw materials can use anthracite coal or coke with a particle size of 8 to 10 mm, which improves the utilization rate of raw materials entering the factory. It has no pollution to the atmosphere, small equipment maintenance workload, and low maintenance costs. It is suitable for use in places with anthracite coal and improves the existing atmospheric pressure fixed layer intermittent gasification technology.
3. Lurgi fixed bed coal pressurized gasification technology
Mainly used for gasification of lignite, non-caking or weakly caking coal. The raw coal is required to have high thermal stability, good chemical activity, high ash melting point, high mechanical strength, non-caking or weak caking, and is suitable for the production of city gas and fuel gas. The tar and hydrocarbon content in the gas produced is about 1%, and the methane content is about 10%. Tar separation and phenol-containing wastewater treatment are complex and are not recommended for the production of syngas.
4. Ash fusion coal gasification technology
Technology from Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences. It is characterized by wide adaptability to coal types, and it is a fluidized bed gasifier. The coal ash does not melt, but only ash and slag are melted into spherical or lumpy ash and slag is discharged. It can gasify lignite, bituminous coal with low chemical activity, anthracite coal, and petroleum coke, with relatively small investment and low production cost. The disadvantage is that the operating pressure is low, and the problems of environmental pollution and fly ash storage and comprehensive utilization need to be further solved. This technology is suitable for small and medium-sized nitrogen fertilizer plants to use local or nearby coal resources to change the raw material route.
5. Ende pulverized coal gasification technology
It is an improved Winkler ebullated bed coal gasifier, suitable for gasifying lignite and long-flame coal. The raw coal is required to be non-caking or weakly caking and has low ash content.<25%～30%，Ash melting point is high、Good low temperature chemical activity。There are a total of devices built and under construction in the country13set22gasifier，Already put into production are16tower。Fluidized bed gasifier，temperature in the middle of the bed1000～1050℃。At present, the largest gasification furnace gas production is4Ten thousandm3/hsemi-water gas。The disadvantage is that the gasification pressure is normal pressure，Single furnace gasification capacity is low，Product gasCH4Content up to1.5%～2.0%，Large amount of fly ash、The problems of environmental pollution, fly ash storage and comprehensive utilization need to be solved。This technology is suitable for small and medium-sized nitrogen fertilizer plants with lignite nearby to change the raw material route.。
6.GE coal water slurry pressurized gasification technology
It belongs to the entrained bed pressurized gasification technology. The raw coal transportation, slurrying, and pumping into the furnace systems are simpler than the pressurized gasification of dry pulverized coal. It is safe, reliable, and saves investment. The production capacity of a single furnace is large. Currently, the largest coal input capacity of the international gasifier is 2,000t/d, and the maximum capacity of the domestic gasifier that has been put into production is 1,000t/d. The maximum capacity of the gasifier in the design is 1600t/d. It has wide adaptability to raw coal. Gas coal, bituminous coal, sub-bituminous coal, anthracite coal, high-sulfur coal, low-ash melting point inferior coal, petroleum coke, etc. can all be used as gasification raw materials. However, it is required that the ash content of the raw coal is low, the ash melting point in the reducing atmosphere is lower than 1300°C, and the ash slag has good viscosity-temperature characteristics. The gasification system does not require external supply of superheated steam and N2 or CO2 to transport raw coal for gasification. The total thermal efficiency of the gasification system is as high as 94% to 96%, which is higher than Shell dry pulverized coal gasification thermal efficiency (91% to 93%) and GSP dry pulverized coal gasification thermal efficiency (88% to 92%). The gasifier has a simple structure and is lined with refractory bricks, making it easy to manufacture and low in cost. Gas dust removal is simple and does not require expensive high-temperature and high-pressure fly ash filters, thus saving investment. Six sets of equipment and 15 gasifiers have been built and put into operation abroad; 7 sets of equipment and 21 gasifiers have been built and put into operation domestically, and 4 sets of equipment and 13 gasifiers are under construction and design.
7. Multi-component slurry pressurized gasification technology
The coal gasification technology with independent intellectual property rights developed by the Northwest Chemical Industry Research Institute is a downward gas production with air flow sheet burners. A typical multi-component slurry contains 60% to 65% coal, 10% to 15% oil, and 20% to 30% water. The author believes that the method of adding oil when preparing multi-component slurry is not in line with the current policy of my country's nitrogen fertilizer industry to replace oil with coal to change the raw material route, and needs to be improved.
8. Multi-nozzle (four-burner) coal-water slurry pressurized gasification technology
It was jointly developed by East China University of Science and Technology, Yankuang Lunan Fertilizer Factory, and China Tianchen Chemical Engineering Company. It is an air-flow bed with multiple burners descending to produce gas, and the gasifier is lined with refractory bricks.
9.Shell dry coal pulverized pressurized gasification technology
It belongs to the air-flow bed pressurized gasification technology. It can gasify lignite, bituminous coal, anthracite coal, petroleum coke and coal with high ash melting point. The raw coal fed into the furnace is dried and finely ground dry coal powder. Dry pulverized coal enters from the lower part of the gasifier, which is a multi-burner upward gas production system. At present, the largest gasification furnace in foreign countries has a processing capacity of 2000t/d coal and a gasification pressure of 3.0MPa. This gasifier uses water-cooled walls without refractory brick lining. Coal with a high ash melting point can be gasified, but limestone still needs to be added to the raw coal as a flux. Since 2000, 19 units have been introduced in China. Its target products include synthetic ammonia and methanol, with gasification pressure of 3.0 to 4.0MPa. The Shell coal gasification unit introduced in my country only has one gasifier for single-series production and no backup furnace. Whether it can operate continuously and stably all year round in coal chemical production remains to be tested.
10.GSP dry coal pulverized pressurized gasification technology
It belongs to the entrained bed pressurized gasification technology. The raw coal fed into the furnace is dried and ground dry coal powder. The dry coal powder enters from the top of the gasifier. It is a single-burner downward gas production. There are water-cooled wall internals in the gasifier. At present, the coal input capacity of the largest foreign GSP gasifier is 720t/d lignite. Because it adopts water quenching process, the investment is less than that of Shell furnace, and it is suitable for coal chemical production. Normally, liquefied gas or other flammable gases should be burned to facilitate ignition, prevent flameout and ensure safe production.
11. Two-stage dry coal pulverized pressurized gasification technology
Xi'an Thermal Engineering Research Institute has successfully developed coal gasification technology with independent intellectual property rights. Gasizable coal types include lignite, bituminous coal, lean coal, anthracite coal, and coal with high ash content and high ash melting point, which do not produce tar, phenol, etc. Its characteristic is that it adopts two-stage gasification. Its disadvantage is that the CH4 content in the synthesis gas is relatively high, which is detrimental to the production of synthetic ammonia, methanol, and hydrogen. The waste heat boiler type gasification device is suitable for combined cycle power generation. Its demonstration device with a coal input capacity of 2000t/d, a two-stage dry coal pulverized pressurized gasifier (waste heat boiler process) has been decided to be used in Huaneng Group“Green coal power”Project, another demonstration device with a coal input capacity of 1,000t/d, a two-stage dry coal pulverized pressurized gasifier (quenching process) has been decided to be used in the 300,000t/a methanol project of Inner Mongolia Shilin Chemical Co., Ltd.
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