Having trouble at the beginning of the project, seeking help~~! !
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1. The circulation rate in the regeneration tower is around 65 tons, and the liquid levels in all the towers are within the specified ranges. The pressure at the top of the tower is 0.09, while the bottom temperature is kept at 122 degrees. All process parameters are being maintained well. However, the hydrogen sulfide level in the lean liquid is quite high, around 2.56. What could be the reason for this? How to solve it? 2. What does the hydrogen sulfide content at the inlet and outlet of the hydrogenation reactor indicate? Is it better to have high imports and low exports, or low imports and high exports?
The function of the hydrogenation reactor is to convert SO2 into H2S through hydrogenation; naturally, the hydrogen sulfide level at the outlet is higher than that at the inlet.
1. The circulation rate in the regeneration tower is around 65 tons, and the liquid levels in all the towers are within the specified ranges. The pressure at the top of the tower is 0.09, while the bottom temperature is kept at 122 degrees. All process parameters are being maintained well. However, the hydrogen sulfide level in the lean liquid is quite high, around 2.56. What could be the reason for this? How to solve it: Answer: What is the concentration of the lean liquid in your system? Is it the insufficient concentration of the lean liquid that is causing the problem? Judging from your temperature, it’s about the same. Also, the sample is analyzed again, and analysis isn’t always very accurate. 2. What does the hydrogen sulfide content at the inlet and outlet of the hydrogenation reactor indicate? Is it better to have high imports and low exports, or low imports and high exports? What is the principle of a hydrogenation reactor? It is to convert sulfur dioxide into hydrogen sulfide. Since new hydrogen sulfide has been produced, it must be higher than before.
Reply to 3# zhezi2009.wang: The concentration of the lean solution analyzed by our equipment is above 21, while the hydrogen sulfide content in the rich solution ranges from 6% to over 7%; the hydrogen sulfide level in the lean solution is between 2% and 3.7%
This person is absolutely right; these are all details that deserve attention
Reply to 4# chenlaid: The concentration seems a bit low; it’s usually kept between 30-40. Thicken it to see the effect; otherwise, add more amine solution.
In fact, the control of the regeneration tower is very important. By maintaining an appropriate pressure at the top of the tower and ensuring there is enough regeneration steam, the temperature at the bottom of the tower remains constant, and thus there should be no issues with the quality of regeneration. Of course, different circulation rates require different amounts of steam; the key is to find the right balance. Every adjustment to a parameter will cause changes in other parameters, but adjustments can lead to a new equilibrium.
First, the solvent concentration is a bit low; generally, it needs to be at least 25% or higher to meet the regeneration requirements. Second, what is the design capacity of your regeneration tower? Could it be that the opening ratio of the trays (in the case of a plate tower) is too high, resulting in insufficient gas-phase load and thus liquid leakage? We encountered a similar situation during the first start-up of our plant; we had to increase the amount of steam used to resolve the issue. It was later found that the opening ratio was indeed too high, so during maintenance some of those openings were manually blocked, and since then the system has been operating properly.
The low temperature in the regeneration tower can be increased further; try controlling the top temperature of the tower at around 110°C. Regarding the H2S concentration issue at the inlet and outlet of the hydrogenation reactor you mentioned, is it during the presulfurization phase or during normal operation? If it is the former, the inlet should be higher than the outlet.