Circulating fluid bed boiler flue calcium injection and desulfurization process

Abstract

The flue gas injection calcium desulphurization process in a circulating fluidized bed boiler of the invention is characterized by sending CaO power to a horizontal flue of a cyclone separator with the temperature being equal or lesser than 850 DEG C or a first-level steam superheater or / and tail flue to carry out the desulphurization reaction for desulphurization. The concrete method is as following: spraying the desulfurizer power with the particle size being 100 to 800 items and the preference being 200 to 800 items to a furnace cavity through an overgrate air inlet, the middle part or the upper part of the furnace cavity of the boiler; wherein, the desulfurizer is limestone powder, raw lime powder or hydrated lime in powder. The device of the invention has the advantages of having a simple structure, not changing the inner structure of the boiler basically, not affecting the normal-index operation of the boiler, having high desulphurization efficiency, needing little investment and having low running cost, thereby realizing the ideal goal of low-cost desulphurization, achieving the perfect combination of economic benefit and social benefit of environmental-protection and discharging-reduction and having great popularization value.

Description

technical field [0001] The invention belongs to a flue gas desulfurization process in a boiler furnace, in particular to a calcium spraying desulfurization process for flue gas in a circulating fluidized bed boiler furnace. Background technique [0002] In various types of thermal power plants in my country, almost all boilers use coal as fuel. Because coal contains ash and mineral sulfur, the combustion process will produce smoke, SO 2 and NO X and other pollutants. Circulating fluidized bed boiler (hereinafter referred to as CFB), because its combustion temperature is between 850°C and 950°C, it can effectively control the NOx in the combustion process of coal. X CFB is widely used in small thermal power plants because of its wide fuel adaptability and the ability to directly add limestone into the furnace for desulfurization. However, among the hundreds of CFBs that have been put into operation, less than 10% of the boilers are actually put into limestone desulfurizat...

AI Technical Summary

Problems solved by technology

In the actual operation process, sometimes in order to cope with the inspection, the molar ratio of calcium to sulfur must reach more than 3:1 to barely meet the emission targets of environmental protection requirements. In the end, most CFB users cannot normally spray calcium desulfurization due to the loss of economic benefits

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