I would like to ask everyone about the SCOT process

For this SRU project here, there is only one quench tower and one absorption tower

Traditional exhaust gas absorption towers generally use a single-stage absorption process, which features simple operation and relatively low capital investment for the equipment. However, the hydrogen sulfide content in its purified exhaust gases is generally above 100 ppm. Especially when there are fluctuations in the operation of the CLAUS sulfur recovery unit, its purification capacity is relatively poor. The absorption tower is equipped with packing at both ends; the solvent is separated, and the semi-poor liquid is fed into the tower. The exhaust gas enters at the bottom of the tower, where it is first absorbed by a semi-poor liquid and then by a concentrated poor liquid. This approach has the following advantages: 1. The hydrogen sulfide content in the exhaust gas can be reduced to 50 PPM or even lower, with an overall sulfur recovery rate of over 99.8%. 2. A high absorption rate is maintained under all conditions; even if there are operational fluctuations in the sulfur recovery stage, the two-stage exhaust gas absorption process ensures that the hydrogen sulfide content in the exhaust gas remains very low. 3. The combination of a two-stage absorption process with a two-stage regeneration process in the regeneration tower can also reduce the energy consumption of the facility. 4. By using a process without an on-line booster pump, the pressure in the absorption tower is low, which is unfavorable for absorption; the two-stage absorption process can enhance the absorption efficiency and compensate for the negative effects of pressure on absorption

Haichuan has really gained a lot of knowledge. However, could you please explain in more detail the origin of the semi-poor liquid? Is it sufficient to use the rich liquid from the bottom of the absorption tower? The semi-poor liquid and the highly poor liquid are injected by two separate pumps, right? And what does it mean by two segments of analysis? Also, which organization is doing this at the moment? More!

The semi-poor liquid and the highly poor liquid are introduced by two pumps. The source of these liquids is actually a regeneration tower divided into two sections: the upper section contains the semi-poor liquid, which is partly sent to the absorption tower and partly goes to the lower section where it is further regenerated into the highly poor liquid

Two-stage absorption and two-stage regeneration represent further improvements to the SCOT process; this approach enables the hydrogen sulfide content in the purified exhaust gas to be reduced to less than 50PPM, while also saving 30% of steam usage. It is energy-efficient and environmentally friendly.

The sixth sulfur unit at Zhenhai Refining & Chemical uses two-stage absorption and two-stage desorption

Technical Progress in SCOT Process for Exhaust Gas Treatment -- Petroleum Refining & Chemical Engineering, Issue 10, 2003. The main drawback of the SCOT process is its high capital costs, operating expenses, and energy consumption. In light of this, the technological advancements in SCOT process in recent years have focused on two interrelated goals: improving sulfur recovery rates while simultaneously reducing energy consumption and waste. The technical advancements and applications of the SCOT process are reviewed from aspects such as improved process design, operating conditions, equipment and instruments, solvents and catalysts.