Sintering flue gas waste heat staged cyclic utilization and pollutant emission reducing process and system

Abstract

The invention provides a sintering flue gas waste heat staged cyclic utilization and pollutant emission reducing process and system. According to the process, sintering flue gas is divided into low-temperature high-oxygen low-humidity section sintering flue gas, medium-temperature low-oxygen high-humidity section sintering flue gas and high-temperature high-oxygen low-humidity section sintering flue gas according to the emission characteristics of flue gas temperature and oxygen concentration and humidity. The low-temperature high-oxygen low-humidity section sintering flue gas is subjected to dust removal and then is led into a sintering machine for hot air sintering and hot air ignition. The medium-temperature low-oxygen high-humidity section sintering flue gas is subjected to dust removal and desulfurization treatment. The high-temperature high-oxygen low-humidity section sintering flue gas is mixed with cooling machine waste gas and then is led into the sintering machine for hot air sintering. The sintering flue gas waste heat staged cyclic utilization and pollutant emission reducing process and system can conduct staged utilization on flue gas waste heat, recover low-temperature sensible heat in flue gas, enable carbon monoxide left in the sintering flue gas to be secondarily combusted and reduce the energy consumption in the sintering process on the premise that the quality and yield of sintered ores are ensured. Cyclic flue gas utilization is achieved, the pollutant emission quantity of unit sintering ores and total emission quantity of the sintering flue gas are reduced, and the sintering flue gas waste heat staged cyclic utilization and pollutant emission reducing process and system have very high energy-saving emission-reduction value.

Description

technical field [0001] The invention belongs to the technical field of sintering production in the metallurgical industry, and relates to a sintering flue gas waste heat classification and recycling process system, in particular to a sintering flue gas waste heat classification and recycling process and pollutant emission reduction process and system, and more specifically to a smoke-based The sintering flue gas waste heat graded recycling and pollutant emission reduction process and system with different temperature, oxygen concentration and humidity emission characteristics. Background technique [0002] The iron and steel industry is a highly polluting industry, and a large amount of flue gas is generated during the iron ore sintering process, such as a 495m 2 When the sintering machine is in normal production, the amount of flue gas emitted is as high as 1.2 million standard cubic meters (Nm 3 / h), in addition, due to the high air leakage rate (40%-50%) and high solid m...

AI Technical Summary

Problems solved by technology

[0003] The energy consumption of iron and steel sintering accounts for about 8% to 10% of the total energy consumption of iron and steel production. It is second only to iron making and is the second largest energy-consuming household in iron and steel production. 52% of the heat comes from the main flue of the sintering machine (24 %) and coolers (28%) are discharged into the atmosphere as sensible heat. According to statistics, the utilization rate of waste heat in the sintering process in my country is less than 30%, and the utilization rate of sintering flue gas is basically zero.

However, the utilization rate of waste heat resources of sintering flue gas is low, and the influence of humidity in flue gas on sintering ore is not considered.

CN 101832572B extracts the flue gas from the air box at the tail of the main flue of the sintering machine, passes through the waste heat boiler for heat exchange, and then discharges it after desulfurization and dust removal. The role of row

CN 104132550A divides the main flue of the sintering machine into three sections, extracts the flue gas from the high-temperature medium-sulfur section and returns it to the sealed cover of the sintering machine trolley for circulation, and at the same time supplements the oxygen required for the combustion of the sintering machine. This invention achieves energy saving and reduction through flue gas circulation. The purpose of exhaustion is to facilitate the desulfurization of sintering flue gas, but the amount of exhaust gas circulation is small, the effect of energy saving and emission reduction is low, and the influence of flue gas humidity on sinter production is not considered

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