Bag filters are often burned out during the drying and dust removal of lignite
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Our carbonized coal drying and dust removal bags have caught fire many times already; it’s really worrying me. No matter what I try, the bags keep catching fire. We use primary cyclone dust removal with a temperature control of 160 degrees Celsius, along with 6 chambers and 30 pulse valves. I see that others use it in the same way, but we always burn the bags; no open flame is used, yet the burning is even more intense than with an open flame. The cold air valve is used as well, as is the bypass valve. We burn the bags at around 140 degrees Celsius, and the ash is removed on a regular basis. I just can’t figure out why. If anyone here knows the answer, please help me out
Make sure first that your bag can withstand such high temperatures; if it operates at temperatures above 120°C for an extended period, there is a high risk of the bag being damaged
Could it be that there are dead corners in the airflow path inside the bag filter, causing a certain bag to be locally overheated?
Our dust removal system operates with air entering from below and exiting from above. I went in to take a look, and it seems there are no dead corners. The bags we use for burning are burned most intensely in the range from below the grating to 300
If the filter bags generate static electricity, there is a high possibility of combustion at such temperatures.
The bags we purchase are Borgne heat-resistant bags that can withstand temperatures of 260 degrees Celsius. The temperature is usually around 150 degrees Celsius.
It’s probably still caused by static electricity. The fluoromesh of the Borgnet 260 is made of glass fiber, while the felt uses aramid and is not fire-resistant. If static electricity causes fuel issues, anti-static filter media must be used.
Let’s analyze the reasons systematically: 1. A temperature of around 140° is not high at all, and it falls within the temperature range that the filter bags can withstand; therefore, it’s not the high temperature that is to blame. 2. The fact that there are no dead zones in the airflow indicates that there is nothing wrong with the design of the bag filter. 3. Since the operation takes place at the outlet of a drying kiln, there are no sparks or other ignitable substances present. Possible causes include: 1. Could the temperature have suddenly risen to very high levels at some point? 2. Might the quality of the filter bags themselves be substandard? 3. Could static electricity be responsible for damaging the filter bags?
This post was last edited by yzhang2010 on 2011-8-29 at 23:03. The automatic control system we use causes the flow to go through a bypass route once the temperature exceeds 180 degrees Celsius, thereby avoiding the bag house. I’ve analyzed the reason for this phenomenon; it’s likely that the dust in the bags catches fire on its own. The carbonized char particles, after being placed there, start burning on their own after a few hours. If there’s wind present, then a fire breaks out. But how can this problem be addressed? We use air to remove dust, and currently our approach is to prevent dust from accumulating in the bag house, as we’re concerned about spontaneous combustion
It must have been electrostatic ignition; there’s a bypass temperature sensing point installed there. If I’m not mistaken, the spacing between the holes in the ceiling grid should be smaller than designed.
It’s probably caused by static electricity; try using a polyester cloth that is oil-resistant, anti-static, waterproof, and heat-resistant.