Ammonium sulfide and desulfurization
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In the chemical production workshop of a coking plant, when purifying gas, should ammonium sulfate be produced first or should desulfurization take place first?
It depends on which desulfurization method is used. If ammonia-based desulfurization is employed, desulfurization must be carried out first; otherwise, there will be no ammonia source available after ammonia washing. Even if ammonia is added later, it will exacerbate corrosion of the subsequent equipment. For other desulfurization methods, it is also best to carry out desulfurization first in order to reduce impurities.
Some books mention coking oven gas from the ammonium sulfate production section as the starting point when discussing desulfurization; yet other books, when talking about ammonium sulfate, refer to coking oven gas from the desulfurization section. So I’m not sure which one should be dealt with first. What was said upstairs is correct; in the case of ammonia-based desulfurization, desulfurization is carried out first, of course.
In the ammonia-based desulfurization process, desulfurization is carried out first; here we use vacuum potassium carbonate for desulfurization, with desulfurization taking place later
As for other desulfurization methods, desulfurization can be carried out later; by washing away the ammonia first, corrosion throughout the system is reduced, and there are fewer impurities as well. Therefore, it’s not possible to simply say which one should be placed at the back and which one at the front; the decision has to be made based on the manufacturing process.
In terms of operating costs, I believe the ammonia-based pre-desulfurization method is more economical, but a pre-cooler needs to be installed before desulfurization
Ammonia-based desulfurization is often carried out under negative pressure, without the need for a pre-cooling tower; however, the choice still depends on the specific conditions of each process. Now, there are many applications of the negative-pressure ammonia desulfurization method.
In our factory, ammonium sulfate is produced first, followed by desulfurization; the purpose of desulfurization is mainly to ensure the quality of methanol produced later.
For applications where the requirements for hydrogen sulfide are not high, pre-desulfurization is used, with ammonia being the main agent for this purpose. For applications with strict requirements, such as those where hydrogen sulfide levels need to be kept below 20 mg, post-desulfurization is employed; alkaline desulfurization yields better results in such cases
This post was last edited by hao101029 on 2012-3-20 21:03. I agree with the view above; generally, desulfurization is carried out first and then ammonium sulfate production, and this is the process used in my factory.
The vacuum potassium carbonate process seems to be better. Our factory uses both the HPF process and the vacuum potassium carbonate process, and I think the latter is more cost-effective