H2S concentration tower and CO2 stripping tower
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In the Lindlar low-temperature methanol washing process, it seems to me that the H2S concentration tower and the CO2 stripping tower serve similar purposes, both aiming to strip out CO2 gas. Then what is the reason for having an additional CO2 stripping tower? I have been working with the low-temperature methanol washing process for only a short time; I hope those with more experience will be kind enough to share their insights with me.
A carbon dioxide stripping tower can produce carbon dioxide of high purity; all urea production facilities are equipped with both stripping towers and concentration towers. Methanol plants are all integrated together.
In our methanol plant, carbon dioxide is emitted directly. Are the two towers separated in order to prepare for the future recovery and reuse of carbon dioxide? Also, some carbon dioxide stripping towers are placed ahead of the hydrogen sulfide concentration towers – is there any particular order regarding the placement of these two types of towers?
For further concentration of hydrogen sulfide, our plant also has CO2 stripping towers; the acidic gas content in the process gas is low, and too little removal of such acidic gases will affect the sulfur recovery process
I think in most plants, the T2 (CO2 product tower) is placed ahead of the hydrogen sulfide concentration tower T3, while some plants, due to their larger processing capacity, install a T6 (CO2 stripping tower) to further concentrate hydrogen sulfide. The principle of the CO2 stripping tower and the hydrogen sulfide concentration tower is the same; both use N2 for stripping!
The function of the gas tower is to further concentrate hydrogen sulfide in methanol; the carbon dioxide produced in the gas stream is not useful, so it is simply released as exhaust gas! But it cannot be said to be completely useless; the carbon dioxide released enters the concentration tower, where it also plays a role in stripping carbon dioxide from methanol. Its main function is to increase the sulfur content in the acidic gas used for desulfurization, thereby facilitating the temperature control required for sulfur recovery
The CO2 flash tower uses reduced pressure flashing to evaporate CO2, while the hydrogen sulfide concentration tower employs N2 gas stripping to remove part of the CO2; its main purpose is to concentrate H2S, providing high-concentration H2S for subsequent sulfur recovery processes. Therefore, their functions are different!
I’m working on my graduation project and I’m struggling with this issue; now that I’ve learned * about it, thank you!