Reasons for high moisture content at the inlet of the drying tower

The moisture brought in by the flue gas is of course a sign that there is an issue with the efficiency of the electrostatic demister; it’s also possible that the amount of air added before drying is too large It’s raining and snowing everywhere right now. Why is a drainage outlet installed in your drying tower? Where is it?

The inlet of the drying tower is equipped with a drain to allow the removal of large amounts of water. So what is the temperature of the gas at the inlet of your drying tower? The water vapor there is saturated; the higher the gas temperature, the more water it can carry. What are the moisture levels after drying? There are various reasons for high exhaust emissions, and high moisture content in the flue gas after it has dried out is also an important factor. A comprehensive analysis is needed.

This is water that has been carried along; it would be much better if two stages of electrostatic fogging were used. Our plant’s old sulfuric acid system has drainage outlets installed on the flue gas pipes at the inlet for drying.

It might be that the temperature of the gas entering the drying tower is too high

1. It is possible that the scrubber tower contains foam or liquid, and in addition, the efficiency of electrostatic fogging is relatively low； 2. High inlet temperature of the drying tower ； 3. Air leakage in the outlet pipe of the drying tower and the inlet pipe of the fan ； Previously, in our factory, there was a risk of severe foaming or liquid presence in the scrubber tower; moreover, the efficiency of the electrostatic fogger was relatively low, and the pipeline from the electrostatic fogger’s outlet to the dryer tower was quite long, estimated to be around 300 meters ； Take measures: 1. Add 4 water seal drainage outlets along the route ； II: Install a secondary demister between the scrubber tower and the electrostatic precipitator, and add a demisting layer to the scrubber tower. It works great!

The reasons are: 1, low efficiency of the electrostatic demister; 2, gas supersaturation; 3, excessive amount of foam

1. Poor defoaming effect. 2. The temperature of the gas entering the drying tower is too high. A large amount of water flows out at the inlet of the drying tower; I think this is due to a defect in the washing equipment, which results in an excessive amount of foam in the gas. If the temperature of the gas entering the tower were too high, this phenomenon would not occur.

The moisture content in the flue gas is as high as 13%; due to the long length of the delivery pipelines, booster fans are installed along the way before the gas reaches the purification system. The inlet temperature of the relay fan is between 97 and 139 – is this due to a high dew point temperature?

A high moisture content in the flue gas, along with the high heat capacity of water, indicates a high enthalpy of the flue gas, which in turn results in an elevated dew point.

How should the water seal drain outlet be designed under negative pressure conditions, and what is its effectiveness?

As long as the height of the flue gas pipe at the inlet of the drying tower is sufficient, a drain pipe can be connected to the bottom of the pipe and a water seal tank inserted to achieve automatic drainage, which is somewhat similar to an atmospheric leg.

It’s probably a problem with the efficiency of the electric demister. If the inlet temperature is high, how can the electric demister handle that?

Check again whether the safety water seal for the electrostatic fogger is properly designed, to ensure that it won’t draw the water inside in. This post was last edited by ffqgwc on 2008-3-2 13:22]

:lol :lol Last edited by ffqgwc on 2008-3-2 13:44 ]

The moisture level at the inlet of the drying tower is too high; generally, this is due to inadequate parameters in the purification process as well as an excessively high flue gas temperature. It is also possible that even if the temperature of the gas exiting the electrostatic precipitator is within the acceptable range or quite low, the water content in the gas can still be high. This might be due to an excessively high gas flow rate; although the temperature drops, the water vapor does not have enough time to condense into tiny droplets before it reaches the drying tower. A drainage outlet is installed at the inlet of the drying tower, depending on the circumstances. Generally speaking, when the distance between the electrostatic mist and the drying tower is large, installing such a drainage outlet allows more time for water vapor to condense into small droplets when the gas flow velocity is high; once these droplets form, they can then be discharged through the drainage outlet. When the moisture level at the inlet of the drying tower is too high, the amount of exhaust gas is definitely large. This is because, with such a high moisture level, the drying tower is unable to absorb all the moisture present in the flue gas; the unabsorbed moisture then enters the conversion section, where it reacts with sulfur trioxide to form acidic vapor and acid mist (this can occur either in the conversion section or in the dry absorption section). Acidic vapor and acid mist are not easily absorbed by the absorption tower. Moreover, they are visible gases – usually white, but sometimes pale yellow or grayish-white. Although their quantity is not large, their volume is more than ten times that of ordinary flue gas, which is why the amount of exhaust gas appears to be particularly high. During the process, acid vapor and acid mist are carried away by the flue gas when the temperature is high; however, at lower temperatures or during shutdowns, they cool down within the equipment and pipes, forming condensed acid that causes corrosion.