The influence of positive and negative pressure during the absorption process
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In the gas absorption process using falling film absorption and filler absorption, what is the difference when the fans are located at the front end and the back end of the absorption equipment, and the equipment has positive pressure and negative pressure respectively? Thanks
1. Positive pressure in the tower is conducive to absorption, while negative pressure is not conducive to absorption.； 2. The fan is installed before entering the tower, and the air inside the fan is dry. ； If the fan is installed after entering the tower, there will be moisture in the fan, and the absorption liquid will precipitate in the fan, which may cause corrosion to the fan.
But we want to absorb the acidic gas and then discharge it. If it is set up in a negative pressure process after the absorption equipment, it should be better for the fan. Moreover, the entire process is under negative pressure to avoid possible gas leakage due to sealing, corrosion, etc. Is negative pressure also possible in this situation? Thanks
The negative pressure you consider throughout the process makes sense. However, for the gas absorption process, the principle is that "low temperature and high pressure" can ensure effective absorption effect and solute yield. Consider using anti-corrosion fans.
Are there any relevant documents or books that introduce this knowledge? Thanks
There are many types of absorption. What kind of absorption you are talking about needs to be analyzed in detail. For example, chemical absorption and physical absorption are different. Simply speaking, positive pressure or negative pressure cannot explain the problem at all. Those of us who engage in process design or production management cannot only consider a certain issue. I guess what you are talking about is somewhat similar to the absorption of sulfur dioxide in flue gas, right? It is recommended that you read books about mass transfer and absorption first. You should be able to find them in the forum. for example: Handbook of Chemical Engineering, Second Edition
I absorb the HCl in the exhaust gas
For this soluble gas, the focus is to strengthen the gas film mass transfer process. like: Increase air speed, increase turbulence, etc. Positive pressure and negative pressure have little effect.
As mentioned above, HCL is a soluble gas, and positive and negative pressures have little effect on the balance. The positive pressure of the fan will not go away when it is positive, and it will go away when it is negative.
There will be problems during actual use, and HCl cannot be absorbed well. I have practical experience. Please give advice from experts
What I want to know is, in your system, is HCl being discharged as waste gas or is it escaping as heat of reaction? The simple truth is, is HCl beneficial or harmful to you? ； If it is harmful, it is recommended to use negative pressure absorption and connect the system to the vacuum system. ； If escape is inevitable, it is recommended to use a fan to minimize losses.
Falling film absorber + packed absorption tower, using sodium hydroxide as absorbent and fan evacuation