Sintering flue gas multipollutant collaborative purification and waste heat utilization system and process

Abstract

The invention discloses a sintering flue gas multipollutant collaborative purification and waste heat utilization system and process. Flue gas generated by a sintering machine 1 enters a bag-type dustcollector 2, the bag-type dust collector 2 is connected with a wet desulphurization device 7, the wet desulphurization device 7 is connected with a flue gas heat exchanger 8, and the flue gas heat exchanger 8 is connected with a catalytic denitration, CO removal and waste heat utilization integrated device 12. The catalytic denitration, CO removal and waste heat utilization integrated device 12 is an n-shaped reactor, and an ammonia spraying grid 9 and a flue gas turbulator 10 are arranged in a left pipeline of a reactor; a guide vane 11 is arranged at a left-end inlet elbow of the reactor, and a rectification grid 13 is arranged at the section of a right-end outlet elbow; and a direct combustion furnace 14, a CO removal catalyst layer 15, an SCR denitration catalyst layer and a standby catalyst layer 18 are arranged in a right pipeline of the reactor. A long-process treatment process is changed into a short-process treatment process, various pollutants are cooperatively treated, ultralow emission of sintering flue gas can be realized, white smoke is eliminated, SO2 in pollutant emission is less than or equal to 20mg / Nm < 3 >, NOx is less than or equal to 40mg / Nm < 3 >, Dust is less than or equal to 10mg / Nm < 3 >, and CO conversion rate is more than 95%.

Description

technical field [0001] The invention belongs to the technical field of pollution prevention and control of sintering flue gas in the iron and steel metallurgy industry, and relates to a multi-pollutant synergistic purification process of sintering flue gas, in particular to a multi-pollutant synergistic purification of sintering flue gas and waste heat utilization system and process. Background technique [0002] Sintering flue gas is a major emitter in the iron and steel industry. In April 2019, the Ministry of Ecology and Environment of my country officially issued Huanqi [2019] No. 35 "Opinions on Promoting the Implementation of Ultra-low Emissions in the Iron and Steel Industry". It is required that the hourly average emission concentrations of flue gas particles, sulfur dioxide, and nitrogen oxides at the head of the sintering machine shall not be higher than 10, 35, and 50 mg / m3 respectively, and the emission standards of sintering flue gas shall be raised. It is impera...

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Problems solved by technology

[0004] The existing process can no longer meet the ultra-low emission requirements; in the ultra-low emission transformation, since the exhaust gas temperature of wet desulfurization is 45~50°C, it is necessary to add multi-stage heating devices such as MGGH, GGH, and heating furnace at the end of the wet desulfurization device. Increase the flue gas temperature to meet the SCR denitrification requirements, and then add baking soda desulfurization and high-efficiency bag filter at the end to achieve ultra-low emission control

[0005] This process of using multiple single equipment in series to treat a single pollutant does not take into account the upgrading of the original equipment and the synergistic purification of pollutants between the equipment, which has the disadvantages of large equipment occupation, high cost, difficult implementation, and high energy consumption. question

[0006] SCR denitrification to increase the temperature generally requires a large amount of gas consumption to reheat the flue gas through a gas heating furnace, and the fuel consumption is huge.

Usually, the gas in the whole plant is limited, and the additional consumption will break the supply balance of the plant area, which will have a serious impact on the production and economy of the plant area

[0007] There are deficiencies in the existing technology for the purification of sintering flue gas. The process of using multiple single equipment in series to treat a single pollutant has problems such as long process flow, large floor area, high cost, high energy consumption, and poor operation reliability. Unable to effectively meet ultra-low emissions for a long time

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