Method and system for cooperatively controlling ash deposition and NOx on heating surface of circulating fluidized bed boiler

Abstract

The invention discloses a method and system for cooperatively controlling ash deposition and NOx on a heating surface of a circulating fluidized bed boiler. The method includes the steps that step 1,fuel to be fed into a hearth of the circulating fluidized bed boiler is analyzed, the molar ratio of nitrogen to soluble alkali metal in the fuel is obtained, and the mass content of nitrogen elementand the mass content of soluble alkali metal element in unit fuel are obtained; step 2, a ammonium dihydrogen phosphate solution and a ammonium phosphate solution are controlled to be sprayed into thehearth in a preset proportion according to the feeding amount of a circulating fluidized bed and the molar ratio and the mass content obtained in the step 1; and step 3, the NOx emission concentration of the outlet of the boiler is detected, and feeding back is carried out; and according to a feedback result, the injection ratio of the ammonium dihydrogen phosphate solution to the ammonium phosphate solution is secondarily controlled, and cooperative control is achieved. Denitration and alkali metal synergistic capture in the combustion process of the high-alkali fuel circulating fluidized bed boiler can be achieved, and the operation time and the efficiency of the boiler are improved.

Description

technical field [0001] The invention belongs to the technical field of solid fuel combustion utilization, in particular to a method and system for synergistic control of ash and NOx in a heating area of ​​a circulating fluidized bed boiler. Background technique [0002] The high content of alkali metals (mainly Na) in Zhundong coal is likely to cause serious ash accumulation and contamination of combustion equipment, which greatly limits the safe and efficient utilization of Zhundong coal, resulting in a large amount of coal resources not being well and effectively utilized, resulting in A waste of resources. In addition, biomass is also a fuel with a high content of alkali metals (mainly K), which is considered as "CO 2 Zero emission" clean and renewable energy, its development and utilization are of great significance to alleviate the shortage of energy supply and the reduction of greenhouse gas emissions. China is rich in biomass energy, with an annual output of hundreds...

AI Technical Summary

Problems solved by technology

The Chinese patent with the notification number CN105276598A discloses a method for simultaneously controlling coking corrosion and NOx emission on the heating surface of a biomass CFB boiler, mainly by spraying a controllable ratio of ammonium sulfate and ammonium bisulfate solutions into the boiler to achieve biomass The low NOx emission of the CFB boiler can also alleviate the coking and corrosion problems of the heating surface of the biomass circulating fluidized bed boiler; but in this method, due to the injection of ammonium sulfate or ammonium bisulfate solution, a large amount of SO will be generated at high temperature 2 , it may be necessary to further equip SO 2 processing means, otherwise SO 2 The emission cannot meet the emission standard, which affects the operation of the equipment

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