The S content in the methanol synthesis tower is above the specified limit
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In actual production plants, the sulfur content in the methanol synthesis tower often exceeds the allowed limits. Is it possible to modify the system by adding a buffer tank before the methanol synthesis tower, and include solid desulfurizing agents in it? I would appreciate some guidance from those with experience
Add it properly in the conversion position. Because there is also a filter before it enters the compressor. Prevent catalyst dust from circulating back into the compressor.
It should be possible; some manufacturers add advanced desulfurization between the stages of the compression units
The buffer cylinder has a limited volume; when precision desulfurization adsorbent is installed, the resistance becomes too high. It is best to install another desulfurization tank separately.
It’s better to add another one; the buffer tank here should be designed based on the operating conditions, and its volume cannot be reduced arbitrarily.
The modification does not add a desulfurization unit; if the buffer tank is converted into a desulfurization unit, it will no longer serve as a buffer. As a result, the gas flow rate entering the synthesis tower may fluctuate, thereby affecting the synthesis efficiency.
“The key issue with the excessive S content in methanol synthesis towers is not the installation of protective measures before the towers; no matter how effective such measures may be, they are only temporary； The S content often exceeds the limit: the likely cause is a problem with the desulfurization unit earlier in the process. Finding the issue within that desulfurization unit and resolving it is the most effective approach. Of course, it is also necessary to install protective measures in front of the synthesis tower to prevent poisoning of the catalyst inside it. Different processes also have different approaches.
The problem of excessive sulfur levels is quite serious; it may be caused by a malfunction in the desulfurization unit or by high loads operating at reduced capacity, leading to elevated sulfur levels. It is best to resolve the issue of excessive levels in the previous stage, in order to avoid catalyst poisoning! It’s better to solve it at the source!
The source is low-temperature methanol washing; many methods have been tried, but the results remain average, and currently it is only possible to keep the level at around 0.8–0.1 PPM in the fresh gas. As someone mentioned earlier, it’s really not good to use desulfurization agents in the buffer tank. So for now, the only option is to let the catalyst be poisoned slowly
Add a precision desulfurization tank to the methanol synthesis unit. However, this depends on whether the compression takes place inside the cylinder or at the cylinder. External mixing is quite suitable; in the case of internal mixing, the operating costs need to be taken into consideration
Excessive sulfur levels are detrimental to the catalyst and can easily cause it to become poisoned. This is a problem that must be solved. I’m not sure if they have a desulfurization tank in the conversion section; if not, one can be added after conversion, filled with zinc oxide. If there is a desulfurization tank after the conversion, it is necessary to check whether the operating parameters of the fine desulfurization section are normal.
The function of the buffer cylinder is to cushion the raw material gas; if it is replaced with a desulfurization tank, the air flow will become unstable, which is more detrimental to operations. In the design, each device has its own function and cannot be changed arbitrarily.
Agree with what was said on the 2nd floor; adding zinc oxide at room temperature after the conversion will suffice