I want to know what the differences are between sulfur recovery processes in coal chemical industry and petrochemical industry

There’s no difference; it’s all the same types of processes, such as WSA, oxidation, and so on.

What aspects are covered in the inspection? Do you plan to have someone downstairs write a paper for you covering all aspects?

The main difference in sulfur recovery between the petrochemical and coal chemical industries lies in the concentration of acidic gases; the lower the concentration, the more difficult it is to carry out the recovery process. This is precisely the key issue that has prevented the coal chemical industry from achieving satisfactory sulfur recovery levels to date.

Generally, sulfur recovery in the petrochemical industry makes use of the sulfur recovery method developed by Shengli Institute, while it is the Claus method that is commonly used in the coal chemical industry. They are all Claus reactions, but in the petrochemical industry, hydrogenation and H2S exhaust gas absorption (using MDEA) are added, and the scale of treatment is generally very large!

The main differences between sulfur recovery units in coal chemical industries and those in petroleum chemical industries are as follows: 1. The scale of sulfur recovery units is smaller. Currently, the capacity of sulfur recovery units in the petroleum chemical industry is typically between 50 and 250 kt per year, with this capacity continuing to increase, whereas in coal chemical industries, the annual sulfur production is usually between 10 and 30 kt. 2. The concentration of acidic gases is relatively low. In natural gas purification plants, acidic gases arise from the absorption process using alkanol amines (such as MDEA), with an H2S concentration that can exceed 50%; whereas in coal chemical plants, acidic gases come directly from syngas purification processes (such as low-temperature methanol washing), and the H2S concentration is generally only 20%–30%. 3. The composition of acidic gases is complex. In addition to H2S and CO2, the acidic gases generated by natural gas mainly consist of common hydrocarbons; whereas the acidic gases produced in coal chemical processes also contain impurities such as ammonia, organic sulfur, methanol, COS, and HCN, which is due to the complex composition of coal. And these impurities have a significant impact on the design of sulfur recovery units. 4. Large fluctuations in acidic gas concentration: Due to the diversity of coal types, the range of variations in acidic gas in coal chemical plants is much greater than that in the petrochemical industry, requiring a higher degree of operational flexibility. 5. Insufficient hydrogen source but sufficient oxygen: Refineries require hydrocracking, which is why they all have large-scale hydrogen production facilities, ensuring an adequate supply of hydrogen. Coal chemical plants generally do not have large-scale hydrogen production units, so there is a shortage of hydrogen supply. On the contrary, coal chemical plants generally have air separation units, providing an ample supply of pure oxygen; this feature is favorable for oxygen-enriched combustion processes, and hydrogen reduction processes are not suitable. Therefore, in terms of treatment processes, the petrochemical industry primarily uses Claus off-gas treatment processes, such as Scot, RAR, SSR, etc. This type of process involves hydrogenating the Claus off-gases, followed by absorption using a solvent such as MDEA, and then returning H2S to the Claus unit; the sulfur recovery rate can reach 99.9%. Coal chemical industry primarily uses Claus-based processes, such as SUPERCLAUS, EUROCLAUS, CLINSULF, and MARA processes. This type of process builds on the Claus process by adding a selective catalytic oxidation stage, thereby increasing the recovery rate to 99.2%–99.5%.

My previous company was involved in petrochemical design; sulfur recovery there relied mainly on the Claus process. The exhaust gases were first subjected to hydrogenation reduction, and then absorbed using solvents such as MDEA before being incinerated

The exhaust gases from coal chemical industries are generally recycled and reprocessed. For example, in coal coking, it goes back to the raw gas pipeline for re-washing

There is cyclic absorption involved in the treatment process; how many coal chemical plants are actually able to meet the standards for SO2 emissions completely? Especially now that the sulfur content in the raw materials used is relatively low, it is basically impossible to meet the standards unless there are significant improvements in the manufacturing process.

Is WSA related to sulfur, as asked by the original poster? Don’t mislead the original poster, hehe:D