Flue Gas Treatment Technology Application

With the rapid economic development, people's living standards are being improved, and environmental pollution has become a modern society one of the major problems faced, and the prevention of pollution, protection of the environment and maintain ecological balance, the community has become a guarantee for the sustainable development of an important measures. China is a country with coal as its main energy. According to Environmental Protection Administration, smoke is China's current air pollution mainly and major pollutants are dust and S02.The problem of acid rain is still serious. Totally, there are eight boilers in Aluminum Company Henan branch, a total of one million tons used in 2002,17,912 tons of dust emissions,2,880 tons of nitrogen oxides, only 85% of removal dust efficiency, only 40% of desulfurization efficiency. Boiler soot emission concentration as high as 1959mg/m3, more than three times the national standard; SO2 emissions over 5,000 tons per year, and was fined by the environmental protection department millions of dollars, but serious corrosion of the equipment. These problems have been seriously hindered the Aluminum Company production of sustainable development. With the increased state energy reduction work, how to strictly implement the responsibility system for energy reduction targets to reduce emissions of soot and sulfur dioxide, is an important issue nearly.To the practical problems, the paper through theoretical analysis, combined with the actual situation, first of all, with alumina production of the original supporting thermoelectric system coal-fired boiler flue gas purification technology and from changes in working conditions, the sewage status, flue gas purification system technical equipment, aspects of analysis, a focus on rehabilitation programmes is: One, the five 75 t/h boiler of small wet dust collector on the basis of water film will be made into a cyclone dust collector plate tower upgrading programme, by strengthening contacts between the gas-liquid, dust removal efficiency is from 85% to 95%, and a small investment, short transformation period. Second, according to the changes in working conditions, the two 160t/h coal-fired boiler ESP system, through the implementation of the existing electrostatic precipitator 90m2 of structural transformation under the premise of the increase a 50m2 ESP system, using parallel operation mode, the removal efficiency increased is 99.5% and dust emission concentration is less than 120mg/m3. Three, in the original 6# boiler wet ESP system reform, the introduction of a breakthrough of the ESP is to overcome the traditional horizontal plate electrostatic precipitator frequent vibration hammer falling,out of the cathode line rupture phenomenon, dust removal efficiency is 99.5% and dust emission concentration is less than 80 mg/m3. Four, in new-built electric plant two 410t/h circulating fluidized bed boiler building, the comparative studies, the bag filter used to replace the original project feasibility study and preliminary design in the use of electrostatic precipitator flue gas purification, the operation after removal efficiency reached is 99.8%, and emissions is less than 50mg/m3.According to various gas working conditions, dust, smoke, and ESP performance analysis of the main factors, we identified the use of the electrostatic precipitator structure. By calculating,we identified collecting efficiency, electric speed, great spacing, efficient driving speed ESP main technical indicators and C-type anode plate, a new cathode arista line, a few electric field, cross-sectional field, the field length, structure of dust, ash and gas ratio calculated, lose velocity, lose gray ash capacity and ash transportation system main technical indicators.Based on the basic principle of the desulfurization of coal-fired boiler and flue gas desulfurization technology at home and abroad, as well as the comparative analysis with the industry, the use of alumina from evaporation processes alkaline wastewater, the use of dual-alkali desulfurization process,80% of desulfurization efficiency, the realization of governance waste.Finally, to the entire system of alumina thermal coal-fired boiler flue gas purification technology transform,the economy and environment-benefit analysis, we can produce 4 million yuan annually in direct economic benefits.