Equipment Overview and parameters
The purification system of blast furnace gas is gravity dust collector + bag dust collector. The coarse particles and dust of raw gas are removed in the gravity dust collector to reduce the dust concentration of the gas to less than 6G / Nm3 (under high pressure). When the temperature of the semi clean gas is higher than 280 ℃ or lower than 80 ℃, the gas is released for a short time to prevent the high temperature of the gas from burning the bag or dewing the bag at low temperature. The dust concentration of the gas purified by the bag dust collector should be less than 80 ℃ 10mg / m3, design requirements 5mg / m3, each box has a bag leak detector, when the gas dust concentration is greater than 10mg / m3, alarm, computer display the box. The net gas enters into the gas pipe network through the pressure reducing valve group, which is connected with the first phase gas pipe network. The group controls the top pressure of the blast furnace. The net gas pressure entering into the gas pipe is 10KPA, which can be used by all users.
The main parameters of bag filter are as follows:
Number of boxes: 10
Number of filter bags per box: 238
Filter bag specification: D * L * f2130 * 6000
Material: PTFE
Service temperature: 10-260 ℃
Instantaneous temperature: 300 ℃
Filtration load: 35nm3 / m2. H
Gas filtering capacity of each box: 16250nm3 / h
The gas treatment capacity can reach 162500nm3 / h
After receiving the gas stop instruction from the furnace operator, inform the gas dispatcher to pay attention to the gas pressure before cutting the gas.
（1） Scheduled maintenance: (bag system to catch gas)
1. The bag box should be back blown first.
2. Steam or nitrogen is supplied to the gravity dust collector, and nitrogen is supplied to the raw clean gas pipeline and box.
3. Contact to confirm that the furnace top Φ 550 is opened, and then close the block valve of gravity dust collector and 1.7m butterfly valve.
4. Close the inlet and outlet butterfly valves of 1-10 boxes.
5. Open the Φ 200 and Φ 400 discharge valves of the gravity dust collector, 1 # - 10 # - each box discharge valve and the main pipe discharge valve of raw and clean gas in turn.
6. After detecting that there is no gas in the box and pipes, close the purge gas.
7. Close the 1.7m eyeglass valve behind the pressure regulating valve group.
8. After the gas is stopped, the manhole, explosion-proof hole, ash discharge ball valve, gravity dust collector and ash discharge valve of the box can be opened only when the temperature of the box is less than 60 ℃.
（2） When the top of the blast furnace is not ignited for a short time (within 2 hours), there is no maintenance item for the gas system. After the shut-off valve of the gravity dust collector is closed, the bag system is treated with pressure maintaining.
（3） The gravity dust collector and the raw gas pipeline are used to drive the gas when the blast furnace is short-term shut down and the top is ignited.
（4） Fluorescent powder leakage detection: regularly carry out fluorescent powder leakage detection for bag type dust removal system. Bag type leakage detection is a very important part of system maintenance. It is necessary to select VKH fluorescent powder suitable for bag type dust collection
