Some personal views on the new SO2 emission standards

Can the process work smoothly? Another issue is the compressor. Apart from corrosion, the consequences of a leak are unimaginable.

For combined exhaust gas treatment with low-temperature methanol washing, one option is to send the gas to a hydrogen sulfide concentration tower, while another option involves using methanol from the carbon dioxide product tower for washing; it’s not the heat regeneration tower as you mentioned. A company has implemented this; it’s Huisheng, right? Both of these processes are covered by patents.

It is sent to the low-temperature methanol wash concentration tower; by adding a compressor, how can corrosion be prevented so as to avoid leaks, which would otherwise cause unnecessary problems later on. Additionally, it is absorbed in the previous scrubber tower, and then sent back to the regeneration tower for regeneration. The main problem is that the pressure in the front sections is higher than that in the rear sections; how can energy savings be achieved? The original poster has shared the drawings of the two manufacturing processes you mentioned, so we can take a look at how they are implemented.

In my opinion, this adjustment is too significant; it would be possible to achieve standard emissions by making as few changes as possible to the original design.

Actually, none of these are major issues. First, regarding the corrosion problem mentioned on the 4th floor, it can be resolved by choosing the right materials. Moreover, the sulfur recovery exhaust gases are not highly corrosive; the main components are nitrogen, carbon dioxide, and acidic gases. Since the acidic gas pipelines in the low-temperature methanol washing process are not severely corroded, what’s the big deal with these issues? Secondly, regarding the question on the 4th floor about how to return the fluid from the additional washing tower to the regeneration tower, the energy consumption involved is actually quite low. Consider that the additional washing tower is connected in parallel with the carbon dioxide product tower; we simply need to divert a portion of the methanol used for washing carbon dioxide in that tower to the sulfur recovery flue gas washing tower. It is sufficient to pressurize the sulfur recovery flue gas to around 0.3 MPa. Of course, this methanol is not sent back to the regeneration tower as you mentioned, but rather it goes together with the methanol used for washing carbon dioxide in the carbon dioxide product tower back to the hydrogen sulfide concentration tower for further concentration before being sent back to the regeneration tower. Of course, I haven’t looked at their specific procedures in detail, but I think it makes sense. Secondly, regarding what was said about the 6th floor and the original design, I would like to ask: taking the currently common Claus sulfur recovery process as an example, if you want to reduce the sulfur content in the exhaust gases, how do you go about it? Most approaches still do not focus on the washing process. If we are to focus on washing, it would be better to make use of the existing low-temperature methanol washing technology. Not to mention meeting the 400 environmental standards, even 100 standards can be satisfied with this approach; moreover, it allows for the reduction of the need for incinerators, as the hydrogenation exhaust gases can be directly sent to the low-temperature methanol washing system for treatment.

What the original poster mentioned is already a patent; there are several versions available, and it’s worth looking into them. Currently, Nanjing Huisheng is using it, but the specific operational details aren’t very clear. Theoretically, it works perfectly well. In cases where pressure is insufficient during certain stages of absorption, online pressure boosters are used; this approach can be adopted, and the original hydrogen sulfide concentration tower can be utilized for that purpose.