The blast-furnace gas pulse bag filter is mainly composed of box body, pulse injection system, gas release system, waste and clean gas main, nitrogen storage bin, valve, safety explosion venting valve, control and detection system, nitrogen process pipe, steam process pipe, ash discharging and conveying system, filter bag, filter bag keel, water supply and drainage system, ash storage and humidifying system, and piping fittings, etc. After dedusted by heavy force and cooled by the cooler (according to the technical requirement) (after cooling, gas temperature should be 100-250℃), the blast-furnace gas is distributed to each box of the filter by the waste gas main, and flows into the waste gas chamber. Larger dust particles naturally fall into the hopper, and smaller dust particles rise up with gas. When passing through the filter bag, dust is blocked and stay at the outer surface of the filter bag, and gas is purified. The purified gas enters into the clean gas chamber, and is input into the gas pipe network through the clean gas main. Along with continuous filtration, dust on the surface of the filter bag is gathered, and filtering resistance is increased ceaselessly. When the resistance reaches a certain value, the PLC and DCS control system will automatically control the start-up of the pulse valve for ash removal by pulse air injection (clean nitrogen is used as injection air), and dust falls into the hopper. When dust in the ash hopper is accumulated up to a certain amount, the ash discharging and conveying system starts running. Dust is conveyed to the ash storage bin for temporary storage, and then is transported out of the factory by vehicles.
The product belongs to the blast-furnace gas dry dedusting equipment. Compared with the gas pressurizing blowback bag filter traditionally used, it has many advantages of less investment, small occupied area, low energy consumption, high purification efficiency, simple operation, reliable operation, etc., applicable to gas evolution of a blast furnace with a capacity of 380-5000m3 or more. The membrane explosion venting valve of the cylindrical pressure-proof box ensures production safety. All critical parts are imported, greatly improving the reliability of running the complete machine, including the aspects as below:
a. The number of use of pulse valve is more than 1 million.
b. The material level of ash hopper can be measured accurately.
c. Box leak detection and alarming device has reliable and rapid response, and leakage can be measured accurately.
- The material of the filter bag can work for a long term at the temperature of 260℃, and for a short term at the temperature of 280℃. The service life of blast-furnace gas at the temperature of 200℃ may be up to 24 months.
- The dusting system uses the long-bag pulse or low-pressure nitrogen pulse injection system, having many advantages.
- Nitrogen is the optimal deashing medium, contains no dust and no moisture, and its dosage is a few. The supporting system cancels the traditional pressurizing blowback fan and a large number of valves and pipeline, not only saving equipment investment, but reducing energy consumption, and has the advantages of safe operation and low automation.
- The use of long-bag low-pressure pulse deashing technology enhances the purification and dedusting efficiency. Dust content of purified gas should be less than 5mg/m3 (usually, 3mg/m3), solving the problem that gas should be released when pressurizing and blowback deashing, without atmospheric pollution.
- The control system adopts the PLC for automatic control, basically realizing unmanned operation and reliable operation, minimizing the maintenance workload.
- The product has been successfully applied in blast furnaces with a capacity of 350m3 or 750m3 or 1050m3 or 1880m3 or 2500m3 or 5000m3 of domestic steel plants.