Method for reducing emission of carbon dioxide by circulating fluidized bed temperature flue gas circulation oxygen combustion

Abstract

The invention relates to a method for reducing emission of CO2 by circulating fluidized bed temperature flue gas circulation oxygen combustion, which is a method for realizing CO2 emission reduction applied in a circulating fluidized bed boiler based on the technology of temperature flue gas circulating oxygen combustion. The method comprises the following steps: feeding fuel and desulfurater into the circulating fluidized bed boiler, taking the gas mixture of O2 and circulating flue gas as combustion agent, passing through the heating surface at the tail by the flue gas generated by combustion, heating O2 (concentration is 96.5%-98.5%) from an air separation unit, generating temperature flue gas at the temperature of 140-150 DEG C, taking the gas mixture composed of 30%-70% of the temperature flue gas and O2 as oxidant to delivery to a furnace for combustion, carrying out dedusting by a deduster, multi-level condensation and dehydration and compression on the residual flue gas (volume concentration of CO2 is larger than 95%), and realizing resource utilization or storing in a sealing manner. The circulating glue gas is rich in vapor, entrainment unburned carbon and active desulfurater; the method enhances radiant heat exchange in the furnace, solves the problem of insufficient amount of convection heat transfer, improves combustion efficiency and desulfuration efficiency of the furnace, and can realize near-zero emission of gas pollutant; besides, the method can also lower comprehensive power consumption of space division and CO2 compression, and improve generating efficiency.

Description

technical field [0001] The invention relates to a circulating fluidized bed temperature flue gas circulating oxygen combustion to capture CO 2 The method belongs to the technical field of energy saving and environmental protection engineering. Background technique [0002] The large amount of greenhouse gas CO emitted due to the burning of fossil fuels 2 The harm to the environment has aroused great concern all over the world. In numerous CO 2 Among the separation and capture technologies, oxy-combustion technology is a new type of low-cost separation and recovery of CO 2 And the new concept of combustion with low pollutant emissions has attracted the attention of researchers from all over the world. The circulating fluidized bed oxygen combustion technology combined with the circulating fluidized bed clean coal combustion technology has broad application prospects. Compared with pulverized coal furnace oxygen combustion technology, it has three advantages: [0003] 1....

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Problems solved by technology

[0006] But there are also certain shortcomings, high O 2 The reduced volume of the furnace caused by concentrated combustion makes it difficult to arrange the heating surface in the furnace; and if the temperature is too high, it will deviate from the optimal operation of the circulating fluidized bed boiler and reduce the desulfurization efficiency

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