New desulfurization methods
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Dear colleagues: At our coking plant, we are currently using the MDEA method for desulfurization, but the results are not satisfactory. The team leader said that it’s the first plant of its kind in the country, so there is no existing experience to draw on; he has no other choice but to explore things on his own. Is that the case? Could anyone with more experience give us some advice?
You’re joking, right? . . . . . . . The first? ? 、、
Foaming in MDEA systems is not severe, being much lower than that in MEA and DEA. If MDEA is exposed to air for too long, it will turn colored; it is best to filter it before use, which can effectively prevent foaming. Additionally, it is necessary to keep the feed gas clean, free of solid or other liquid impurities, and the lean liquid should also be filtered. By implementing these measures, foaming caused by MDEA becomes minimal, and the tower can be designed as usual. If activated MDEA is used (such as decarburized aMDEA), the activator itself acts as a foaming agent, so an antifoaming agent must be added.
The MDEA method is not widely used for desulfurization; large-scale methanol washing and medium-scale NHD processes are both well-established； MDEA was used by some people in previous years; it is now used less for desulfurization. The second fertilizer production unit at Wuhu Petrochemical seems to use it effectively.
The MDEA method for desulfurization is mainly used to remove acidic gases with low concentrations; for large volumes of gas with high concentrations, it is still recommended to use low-temperature methanol washing!
As far as I know, MDEA is generally used for decarburization. A few years ago I worked on a project to recover carbon dioxide, carried out by the Nanjing Institute. It’s the first time I’ve heard of it being used for desulfurization; there are some types of NHD. Avoiding them should work too; they are all acidic gases. I wonder if it’s economical.
When doing research, you just have to figure things out on your own
MEDA has both desulfurization and decarburization functions; it is a method for sulfur concentration. For sulfur recovery, it facilitates the concentration of sulfur, thereby providing a raw material reserve for subsequent sulfur recovery processes. For refinery gas, MEDA is the technology that is widely used at present ； For coal chemical technologies such as acetic acid, low-temperature methanol washing is a good method, although it is relatively expensive. Regarding the MEDA foaming issue, attention should be paid to light hydrocarbons carrying oil, the bypass filtration of amine-poor liquid, and the addition of defoamers; of course, corrosion protection for the regeneration tower is also a topic of concern at present.
When did you start production that year? As far as I know, MDEA is used in almost all desulfurization processes. Based on our plant’s experience, as long as the oil and carbon content in the solvent is not high, the H2S removal efficiency is satisfactory. However, the total sulfur content in our plant’s products sometimes fails to meet the requirements. I was wondering if any expert could provide an explanation? ?
MDEA is primarily used for desulfurization of hydrogen sulfide, and it is widely applied; of course, MDEA is also used for decarburization, functioning as a physicochemical solvent. However, not much is known about the use of MDEA for sulfur dioxide removal; at least in China, the amine method is rarely used compared to wet desulfurization methods.