Heating device for denitration dilution air system

Abstract

The invention discloses a heating device for a denitration dilution air system. The heating device is installed in an outlet flue of a coal economizer or an inlet flue of a low-temperature superheater, the heating device comprises a plurality of branch pipes, the outlet ends of the branch pipes are arranged in the outlet flue of the coal economizer or the inlet flue of the low-temperature superheater, and the heating device comprises heating branch pipes. The heating device used for heating dilution air is arranged in the outlet flue of the coal economizer or the inlet flue of the low-temperature superheater, and heat of high-temperature flue gas serves as a heating source, so long-term safe and stable operation can be facilitated, the problems of dust accumulation, blockage and the like do not exist, and the heating problem of denitration dilution air can be effectively solved.

Description

technical field [0001] The invention relates to a heating device for a denitrification dilution air system, which belongs to the technical field of denitrification and energy saving. Background technique [0002] SCR (Selective Catalytic Reduction) technology is currently the most advanced, mature and reliable flue gas denitrification technology in the field of boiler nitrogen oxide removal technology in China. NH 3 AS with NO X The basic reduction reactant of the reaction directly affects the selection of the denitrification process route, among which the technology of using liquid ammonia and urea as the reducing agent has been widely used. DL / T 5480-2013 of "Technical Regulations for Flue Gas Denitration Design of Thermal Power Plants" clearly stipulates that "the ammonia gas concentration at the outlet of the ammonia / air mixer in the auxiliary system shall not exceed 5% (volume fraction)", therefore, reasonable control of dilution Air volume is critical. [0003] The...

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Problems solved by technology

[0004] The denitrification system using urea hydrolysis ammonia production technology as a reducing agent, the product gas needs to be transported with heat (about 160 ° C), when ammonia / air is mixed, hot primary air / secondary air is often used as dilution air, for some renovation projects The boiler hot primary air / secondary air margin is small, and the existing blower needs to be modified, and the hot primary air / secondary air will change with the boiler load; due to the air leakage of the air preheater, the hot primary air Dust in the flue gas will be mixed in the wind / secondary air, and long-term operation will cause blockage or wear of the ammonia injection system pipeline

[0005] Some R&D teams also consider using heat exchangers to heat the dilution air, but there are certain risks in the location and application prospects of the heat exchangers; Wear and corrosion are relatively serious, which is not conducive to long-term safe and stable operation; the heat exchanger is arranged in the SCR outlet flue. After the flue gas passes through the catalyst reaction, the by-product ammonium bisulfate will adhere to the surface of the heat exchanger. The thermal effect is reduced, the resistance of the flow field disorder system increases, and the goal of energy saving and consumption reduction cannot be achieved.

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