Graphite falling film absorption of HCL, standards for controlling the flow rate of the absorbent solution

First, lift it up. The key aspect of falling film absorption should be the absorption efficiency, right? Why isn’t there any information on how to control this aspect? The main parameters mentioned are the heat exchange area; so how can we determine the absorption efficiency? ? ? ? ? ?

The effectiveness of a falling film absorber depends mainly on the temperature of the circulating water and the levelness of the inlet distribution in the graphite tubes, in order to prevent uneven flow of the absorbent water.

So how is monitoring carried out during the production process? The temperature of the circulating water is likely to have a significant impact on the heat exchange efficiency. Deviations in flow direction should be identified as part of the result verification process. Are there any effective methods for monitoring during this process? The inlet water temperature is 25°C and the outlet water temperature is 32°C, but the highest temperature of the output material is 70°C. How can this be explained? Thank you.

1. The cooling temperature for falling film absorption should be kept at a low level; a high temperature indicates intense absorption, but it also means that the absorption is incomplete, and the desired absorption effect is not achieved. 2. The absorption tube at the upper part of the falling film absorber is very important; the degree of deviation depends heavily on it. 3. The colleague upstairs mentioned that the discharge temperature is 70 degrees; knowledge of heat exchange is required here. The key factor is the inlet temperature, and generally speaking, a temperature of 70 degrees after absorption is not ideal.

This post was last edited by lioyi2000 on 2015-6-23 13:27. Of course, when using HCl falling film absorption, it is necessary to calculate the flow rate of the absorbent solution. The absorption system needs to be properly configured based on the concentration of HCl you absorb. If the absorption of concentrated HCl gas results in a concentrated salt acid, material balance and heat balance calculations must be carried out first. Then, the flow rate of the absorption liquid is determined based on the temperature and flow rate of the gas to be absorbed. For the absorption of concentrated acid, dilute acid is generally used as the absorbing solution, and dilute acid needs to be produced through a two-stage water absorption process. The exhaust gas is then absorbed using an exhaust gas tower. When designing absorbers, most domestic manufacturers simply calculate the heat exchange area based on the heat transfer rate obtained from heat balance calculations, as well as the K value found in manuals and the logarithmic mean temperature difference calculated accordingly; this approach is far from accurate in practice. Because, think about it: 1. If the heat exchange area is calculated in the same way, will the absorption efficiency be the same whether the device is short and stout or tall and slender? 2. Are the heat transfer coefficients the same in the cooling section of the absorbed liquid and in the gas absorption section? How to calculate it? -- This is related to the temperature after absorption, as you mentioned. 3. Will the different wall thicknesses between the phases in the graphite absorber, along with surface fouling, affect the absorption efficiency? All of the above issues have been carefully calculated; it is only through proper control of the cooling water that the absorption effect can be achieved. Otherwise, no matter how high the cooling water flow rate is set, it may not be possible to achieve the desired absorption effect. Additionally, as the friend mentioned earlier, the design and installation of the upper distribution head are also very important.

According to the calculations, the heat exchange area is 30 square units, and the temperature at the outlet of the material is 40°C; however, in practice it can reach around 70°C. We are using a horizontal tank with a capacity of 10 cubic meters, and at one end of the tank a graphite condenser pump is used for circulating cooling. As the concentration of salt and acid increases, the cooling temperature rises to 70°C, beyond which cooling becomes impossible. Yet the temperature of the water exiting the tank is only around 35°C. How can this be explained? I would appreciate some advice from experts.

We produce hydrogen chloride through the esterification of chlorosilanes; the gas consists mainly of pure hydrogen chloride along with a small amount of ethanol vapor. The graphite condenser is used only as a heat exchanger, and falling film co-current heat exchange is employed, though its efficiency is quite low. Since the manufacturer’s instructions do not mention anything about the amount of absorbent solution to use, I would like to ask for advice from experts. . .