Bag filters for pulverized coal undergo continuous maintenance at the same location every three months
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The powder coal bag filters in the space furnace require maintenance three times every three months. The reason is that the filter bags get damaged under the same cover; about 90% of the damaged filter bags have tears about 10 centimeters below their openings. On the north side of these filter bags (with the inlet being on the north side), there are gaps of around 5 centimeters – these gaps are clearly caused by high temperatures. Such damage occurs only under the west side cover, and approximately 20 to 40 filter bags are affected each time. There is no damage under the cover plate on the east side; this problem emerged only in the past three months. There were few damages during previous inspections, and if any did occur, they were no more than 10. I hope everyone can help analyze the reason.
When the gas temperature is high, the direction of gas flow also plays a role.
Since it is known that high temperatures in the manufacturing process are the cause, why not look for the reasons in process control? The burned areas and the damaged filter bags should provide some guidance; the airflow distribution system should be checked or improved.
It is recommended that, if possible, the original poster take photos and add some annotations; this will make things clearer and it will also help others assist you in solving the problem!
In terms of process control, the temperature is not kept very high either; the temperature at the outlet of the mill is controlled at 103–108 degrees, which is 2 degrees lower than before, as lower temperatures lead to an increase in the moisture content in the coal powder. But it still didn’t work. If the temperature was really too high, then why wasn’t the east side of the filter damaged?
Take a look at the previous photo to see if it’s carbonized or burned out, and what should the oxygen content be? Is there any flow deviation at the inlet or outlet of the recirculated air?
Most of them are worn out; no photos were taken, and some were damaged due to high temperatures. Photos will definitely be taken during the next inspection. How to check if there is flow deviation at the inlet and outlet of the recirculating air? Our C set seems to have a tendency to leak; every time it gets damaged, it’s always in the same spot. The oxygen content is generally below 5%.
On-site assessment can only involve checking where the erosion or ablation is most severe; a more advanced approach is to use software for flow field simulation
It’s likely there is a problem with the airflow guidance at the inlet; this results in excessively high local flow speeds. The normal operating temperature for filters is around 110°C, which is already considered a high temperature. Especially since the wind speed at the inlet is high, if the airflow guidance at the inlet isn’t properly managed, the wind speed near the inlet will be too high, leading to higher temperatures as well. Combined with the high wind speed, the abrasive effect of the airflow along with the high temperature makes it easy to damage the filter bags. The bag filters used by our company feature three layers of airflow guidance, ensuring that the flow speed inside the filter unit remains relatively uniform. The coal powder bag filters we supplied to Anhui Haoyuan in 2018 have been in use continuously for two years now, without any interruptions, and not a single filter bag has been damaged. I work at Henan Xinlianxin Intelligent Equipment Technology Company. If the poster is interested, my phone number is available online; they can get in touch with me