I would like to ask everyone about gas purification and desulfurization
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As the title suggests, I am considering installing a coal-to-gas system with a gas production capacity of around 5000 Nm3/h. I would like to know what desulfurization processes are currently being used What are the advantages and disadvantages of each? Avoid general discussions about dry and wet methods. It would be best to discuss it based on one’s own practical experience. I know that lo-cat technology is good in theory, but I’m not sure how it performs in practice. Those who are familiar with 888 desulfurization, tannin method, or DDS can discuss it. Of course, dry desulfurization methods also exist; the Claus process is probably not suitable. How about other dry methods for pyrite?
Additionally, before gas desulfurization, is it possible to collect the rich gas using methods such as MDEA or low-temperature methanol washing?
Based on the capacity you mentioned, the load on the device is not too high; a choice should be made between Sulferox, Lo_Cat, or biological desulfurization. Sulferox: The sulfur produced by LO-CAT has high viscosity, which results in a much higher likelihood of blockages in the equipment and pipelines, as well as greater difficulties in dealing with such blockages compared to sulfur produced by biological methods. Therefore, operating this process presents challenges related to costs and safety considerations. As for equipment investment, a specific analysis is required. It is recommended to consult relevant technology companies to obtain preliminary technical proposals for comparison, based on the specific gas conditions and components. Using the aforementioned process should not require prior treatment with MDEA to collect the rich gas. However, by checking your intake temperature, pressure, and composition, it might be necessary to carry out some simple preprocessing first, which is much simpler than using MDEA or methanol for preprocessing.
The gas contains about 10% hydrogen, along with another stream of dry gas at a rate of around 1000 Nm3/h, with a hydrogen content of approximately 90%. The simple pretreatment of MDEA involves two main aspects: one is that it can **reduce the volume of gas to be desulfurized, thereby lowering equipment investment ； Secondly, hydrogen has a very wide explosion range, and oxidation treatment is involved in the desulfurization processes mentioned above, which makes it highly dangerous. What's your opinion on this? Could you recommend some organizations with good performance? The desulfurization market is currently full of inconsistencies, and it’s difficult to distinguish between different options based solely on technical solutions!
Are there any other processes besides the simple preprocessing you are referring to? Have you been in contact with the current 888 desulfurization method? How effective is it?
The system you are using has a low gas flow rate, so dry desulfurization alone is sufficient. The simple process is as follows: cooling the gas – desulfurization using activated carbon – desulfurization using iron oxide (marsh iron ore can also be used for this purpose). Since desulfurization takes place at atmospheric pressure, either tower-type (at atmospheric pressure) or box-type desulfurization towers can be used; these options are inexpensive, and their operating costs are not high either. For other methods such as wet flue gas desulfurization, the equipment investment is too high.
Dry desulfurization – Pyrite was also considered, but a capacity of 6000 Nm3/h is still quite high; the amount of elemental sulfur generated is nearly 1000 Kg/h. The replacement cycle for pyrite is too short, probably only two months, and the pyrite used after replacement is difficult to handle as solid waste. Do you have any good suggestions?
Could you please provide the gas composition and requirements? QQ for communication: 1123267744
@I’m not familiar with 888 desulfurization, so it’s hard for me to comment. However, based on the data you mentioned, the desulfurization capacity required is around 25 tons per day; in terms of load alone, it falls within the appropriate range for Sulferox, Lo_Cat, or biological desulfurization. Actually, Sulferox and Lo_Cat are quite similar, while the biological method is significantly different. All three processes involve oxidation steps, but they do not allow oxygen to enter the product gas. This is taken into account in the process design, as these processes can and have been used in natural gas processing; the presence of oxygen in the product gas is absolutely not permitted. From the perspective of desulfurization capacity alone, all these processes are suitable. However, it is recommended to take a comprehensive approach into consideration, such as operation/maintenance costs, equipment investment, secondary pollution, and so on ； Also, based on your current technical capabilities and management skills, which one can achieve stable, consistent, and optimal operation more easily? What stage is your project in? Project proposal, feasibility study? If you do decide to go ahead with the project, it is recommended to have technical discussions with the relevant technology providers. If possible, visit the installed equipment so that you can see and hear it for yourself; this way you will know which option is suitable for you, and you can then discuss the price. If you need to know the contact information of the technology provider, you can leave your details in my private messages and I can recommend them to you; however, you’ll need to discuss the details directly with them.
Additionally, try to handle things in one step rather than two; generally, multi-step processes are more complex, require more space, and result in higher overall costs, unless there are special reasons for doing it that way； CNPC’s long-standing plan for large-scale short-process operations makes sense after all
How did you calculate the amount of elemental sulfur? 6,000 standard cubic meters per hour, with each cubic meter containing 166 g/Nm3 of elemental sulfur.