Location of the exhaust fan and spray tower
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There is a flue gas spraying process: flue gas → spray tower → exhaust fan → chimney. However, during the initial operation, the PP material spray tower was deflated by negative pressure due to a lack of experience. Could it be changed to a flow of exhaust gas → induced draft fan → spray tower → chimney? This way, the spray tower will remain under positive pressure and will not collapse.
To prevent surging, methods such as variable-frequency speed reduction, adding intake vents, and using rupture discs can be employed. If a device that creates positive pressure in front of the spray nozzles is installed but there is no negative pressure behind them, how can it be ensured that the gas passes through the spray tower effectively rather than leaking elsewhere?
Yes, but the load on the exhaust fan will increase.
If a device that creates positive pressure in front of the spray tower and no negative pressure behind it is used, how can it be ensured that the gas passes through the spray tower effectively rather than leaking elsewhere? Your statement implies that you don’t quite understand; what’s the connection between positive and negative pressure? It shouldn’t have any effect on the spray tower, right?
A fan is used to exhaust air from the spray tower, which operates under negative pressure; this ensures proper function even in the event of leaks in the tower structure or air ducts. The exhaust gas can also pass through the designed pipes, be sprayed, and then discharged via a fan. If pressure is applied in front of the spray nozzles using a fan, the spray tower operates under positive pressure, and the exhaust gases will take the path of least resistance to escape, resulting in emissions without proper spraying and without passing through the chimney
Yes, but the situations you mentioned can only be a leak in the tower or a leak in the pipelines. As long as the material selection is fine, it won’t affect the manufacturing process.
Whether negative pressure is created behind the tower or positive pressure is applied in front of it, it is all to provide a driving force for the exhaust gas in the pipeline.
Why increase the load? Power = k * air volume * total wind pressure. Installing it in front of the spray tower doesn’t change the total air pressure either.
Some people believe that the fan, located before the spray tower, can cause significant fluctuations in the pressure at the fan’s outlet； After the spray tower, the pressure at the fan outlet is nearly atmospheric.
Power plants generally consist of: exhaust gas – fan – desulfurization tower – chimney