What are the reasons for the varying concentrations of acidic gases in sulfur recovery?
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In the petrochemical industry, the concentration of acidic gas entering the sulfur recovery unit is generally above 50%, whereas in the coal chemical industry it is around 30%. What causes this significant difference in concentrations?
The concentration of acidic gases in sulfur recovery units is generally above 50%, whereas it is around 30% in coal chemical industries. The fundamental reason for this is the difference in the chemical processes used. If low-temperature methanol washing is used for desulfurization and decarbonization in coal chemical processes, the hydrogen sulfide concentration will be greater than 40% ； If NHD desulfurization and decarbonization is used, the hydrogen sulfide concentration can reach 65%; therefore, different processes result in different hydrogen sulfide concentrations.
The most fundamental reason is the difference in the materials used; crude oil already has a high sulfur content. And coal has a lower sulfur content. It’s coal chemical industry; due to the different types of coal used, the hydrogen sulfide content varies as well. Active participation
In coal chemical industries, if high-sulfur coal is used as raw material and the low-temperature methanol washing process is employed, the hydrogen sulfide concentration in the acidic gas can reach 40%. When NHD is used for decarburization, this concentration may only reach 25–30%. If low-sulfur coal is used, it is difficult to achieve a concentration of 30% either with low-temperature methanol washing or NHD. In petrochemical industries, the CO2 content in the raw gas is already low; therefore, the acidic gas produced after purification mainly consists of H2S, with a very low CO2 content as well. As a result, the H2S concentration in the acidic gas is relatively high.
In NHD decarbonization, the concentration of acidic gases may only reach 25-30%, but we implemented concentration enhancement in the system, which increased the hydrogen sulfide concentration to 65%.