Application Research Of Full Dry Type Dedusting Technology For Blast Furnace Gas On 2500m3 Blast Furnace Of Baogang

The bag dedusting system is used on blast furnace gas. It has advantages of high dudusting efficiency, saving water, saving power, high quality gas, and gas turbidity increasing. And the complete generating efficiency is increased by 30%. It is a comprehensive project of energy saving and environment protection. But for large capacity blast furnace, it features with high pressure, big gas flow rate and difficult to control temperature. Most of large blast furnaces in China are applied with wet type dudusting system. Only some furnaces are applied dry type dedusting furnace, but because low reliability of gas temperature regulation and valve's sealing, all is applied with dry combined with wet type dedusting system.Baogang No.6 blast furnace was put into production by the end of 2006 with volume of 2500 cubic meter. It equipped with complete bag gas cleaning technology. It has a good result.Process flow:Waste gas of blast furnace enters into main 1 inlet lines of bag dedusting catcher via gravity dust catcher and cyclone dust catcher, and then enters into drums of bag dedusting catcher via each branch lines. The cleaned gas enters into clean gas pipe via main outlet line, and then converges into gas network via pressure regulation valve group or TRT. There is a by-pass, which is equipped with heat exchanger for increasing or decreasing gas temperature, between gravity dust catcher and cyclone dust catcher.Flow sheet:The critical temperature regulation system: the technology of full dry type bag dedusting system shows significant all-around benefit. It is very attractive to the enterprises. The main reason that it is difficult to popularize is that it is difficult to achieve temperature regulation (especially for increasing temperature) in very short time. In case bag is fired or burnt, it will cause not only direct economical loss because of exchanging bags, but the worse is the normal production of blast furnace can not be maintained. Much more is that it takes long time to exchange bags. That is just the reason that it is difficult to spread the dry type bag technology. Nowadays, along with the extend of beneficiated burden material and chamotte, the development of operation and management, increase of service time of bags, and temperature resistant, the problem is weakened. The precondition to solve the problem is to have long-term reliable gas temperature regulation system. The situation of overhigh temperature is more than under low temperature for large blast furnaces. But the situation of under low temperature still exists. The bag will be on fire in high temperature, and burnt in low temperature. Therefore both measures for increasing and decreasing gas temperature should be applied.In order to regulate gas temperature for No. 6 blast furnace Baogang, one group heat exchanger is equipped for regulating temperature. The heat exchanger is the basis for safety operation of dry type bag deduster. The system is equipped a high temperature blower. The blower starts up to suck cool air and cool gas when temperature is more than 240℃. And the blower starts up to suck heat source and increase gas temperature. In order to guarantee gas temperature increase and decrease, the reliable heat and cool resource should be available, and the sources should ready at any time for operation, with low power consumption sufficient flow and low cost. At last air is selected as cool source, and waste gas from air heater as heat source.