Operation of the liquefied gas alkali washing system
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This post was last edited by linweihua6 on 2011-11-12 at 22:22. I work at a 1 million-ton delayed coking unit, where an alkaline solution desulfurization system has been added after liquefied gas is treated with ethanolamine for desulfurization. From operating this new system, I have summarized the following points. 1. The concentration should not be too high; 15% is a good value, as higher concentrations can cause the alkali solution to crystallize, while too low a concentration results in poor desulfurization efficiency. 2. The circulation volume should not be set too high; around 4 tons is preferable, as it facilitates regeneration. 3. During winter operations, the pipelines are prone to crystallization; the steam heating effect is poor, and excessively high temperatures can also cause the alkali solution to crystallize. The condensate water within the device can be used for heat tracing, which not only saves energy but also prevents crystallization due to excessive temperatures. 4. Hydrogen sulfide is a killer of alkaline solutions; therefore, if it is present after ethanolamine removal, the alkaline solution loses its activity.
Reply to 1# 15020586786: Is the poster talking about desulfurization of liquefied gas? After hydrogen sulfide is removed using amine solution, liquefied gas must first undergo pre-alkaline washing to eliminate any remaining hydrogen sulfide before entering the desulfurization reactor
It seems different from what you said. Here, after pre-alkaline washing, it goes through a circulation system, which is similar to the amine removal process. It is also reused after being regenerated. I don’t know what principle the moderator is referring to; these days, as the quality of the raw materials deteriorates, the effectiveness is already very low. What is the sulfur content there? Could you share it?
This post was last edited and replied to by linweihua6 on 2011-11-12 at 22:52. Reply to 3# 15020586786: We use liquid film desulfurization; after desulfurization, the thiol sulfur content is generally around 5 ppm. You can do some searches – there are many posts related to liquefied gas desulfurization, such as: hcbbs.com/archiver/tid-172002.html, 2011-10-30; bbs.hcbbs.com/thread-612946-1-1; bbs.hcbbs.com/archiver/tid-439135.html, 2011-10-28
The moderator is referring to the fiber liquid film reactor, right? . . We also use this setup, but we haven’t started working on it yet; we are still in the learning phase. Could the moderator tell us what things need to be paid attention to usually?
I don’t quite agree with the last point mentioned by the original poster; the alkaline washing of liquefied gas is also intended to remove the hydrogen sulfide that remains after ethanolamine-based desulfurization
Our company provides fixed-bed catalytic desulfurization technology for alcohols, and the efficiency of this desulfurization process is very good. The technical specifications promised by our company are a reduction of the total sulfur content in catalyzed liquefied gas to 5PPM, and a reduction of the total sulfur content in coker-derived liquefied gas to 50PPM. The amount of alkali used in our technology is one quarter of that in the traditional extraction-oxidation method. Regeneration at room temperature is also achieved, saving 60–140 MJ of thermal energy per ton of liquefied gas. 15630723397