Circulating fluidized bed gasification furnace starting system

Abstract

The invention discloses a circulating fluidized bed gasification furnace starting system, which comprises a gasification furnace, a coal inlet system, a furnace baking gas system, a flue gas purification system and a flue gas circulation system. According to the present invention, when the furnace is started by using the method, the temperature rising and the pressure increasing of the gasification furnace are simultaneously performed, such that the condition that the temperature rising and the pressure increasing cannot be simultaneously performed in the conventional gasification furnace starting method is solved; by using the un-heated mixed gas as the coal powder conveying gas and the fluidizing agent, the coal powder in the gasification furnace can maintain a good fluidization state, the occurrence of the slagging accident in the gasification furnace can be avoided, the temperature rising and pressure increasing process can be shortened, the furnace starting time can be short, theunqualified synthesis gas volume is low, the waste of resources is reduced, and the environmental protection load of the enterprise is reduced; and the heating process mainly relies on the furnace baking gas, and the furnace baking gas has high heat efficiency, such that the coal powder consumption for ignition is reduced, and the production cost of the enterprise is lowered.

Description

Technical field: [0001] The invention relates to the field of coal chemical industry, in particular to a system for starting a circulating fluidized bed gasifier. Background technique: [0002] At present, there are three types of fluidized bed gasification processes: coal pressurized catalytic gasification, ash fusion and U-gas, all of which adopt the traditional three-stage furnace start-up method of heating up the oven—feeding materials to build the bed—boosting the system. The heating and boosting process must be carried out in strict accordance with the requirements. The following problems exist in the traditional way of starting the furnace: 1. Oven process: The traditional method uses the flue gas produced by the combustion of liquefied petroleum gas or natural gas as the heat source. It takes about 24 hours for the furnace temperature to rise from room temperature to 850°C, and the heating process takes a long time. ;2. The process of feeding materials to build the ...

AI Technical Summary

Problems solved by technology

The following problems exist in the traditional way of starting the furnace: 1. Oven process: The traditional method uses the flue gas produced by the combustion of liquefied petroleum gas or natural gas as the heat source. It takes about 24 hours for the furnace temperature to rise from room temperature to 850°C, and the heating process takes a long time. ;2. The process of feeding materials to build the bed layer: after the furnace temperature rises to 580°C, the gasification agent and pulverized coal are introduced into the furnace. Since the temperature of the pulverized coal itself is low, the furnace temperature will drop directly after being put into the furnace, resulting in The coal gasification reaction cannot be carried out normally; therefore, part of the pulverized coal input at this stage is burned to increase the furnace temperature, and the other part participates in the gasification reaction, but because the furnace temperature and pressure cannot meet the requirements of the gasification reaction, it is not completely gasified , can only be discharged out of the furnace along with the synthesis gas, resulting in low quality and high oxygen content of the synthesis gas, which cannot enter the follow-up section, and is prone to explosion when sent to the torch treatment, so it can only be discharged into the atmosphere, which is not only a serious waste of resources, but also Cause pollution to the environment; 3. Boosting process: Before the boosting process starts, it is necessary to heat-tighten the equipment and pipelines to ensure the airtightness of the equipment and pipelines, and then gradually increase the pressure from normal pressure to the predetermined pressure value according to the actual situation , because the fluidized state of the charge in the furnace will change drastically at the key point of boosting pressure (generally 1.0MPa, 2.0MPa, 3.0MPa), once an unstable flow pattern or local overtemperature occurs, it will lead to gasification Furnace slagging accidents; therefore, when rising from one critical point of pressure to another, not only the pressure increase rate is required to be gradually reduced, but also the duration of maintaining the higher pressure critical point is required to be continuously increased to ensure that the fluidized bed The bed temperature and pressure inside the gasifier are within a controllable range and have a good fluidization state; therefore, the boosting process lasts for a long time, generally taking several days

The above problems will become more and more obvious with the increase of the volume of the circulating fluidized bed gasifier. On the whole, the start-up process of the traditional circulating fluidized bed gasifier has long operation period, serious waste of resources, complicated process, great difficulty and serious problems. The problem of polluting the environment

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