The chloride ion level in high-purity methanol (AA grade per US standards) is above the allowed limit
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I would like to ask everyone: what are the main causes of excessive chloride levels in pure methanol (meeting AA grade or IMPCA grade standards)? How should pretreatment be carried out to prevent it? Thank you!
Is the chlorine content in the syngas exceeding the limit? I’m just guessing. I hear your company is pretty good; we don’t do this kind of work
Logically speaking, methanol should not contain any chlorine. Because dechlorination devices are built into the purification process; if chlorine is present in the syngas produced later on, the methanol catalyst will not be able to function for a long time. If the situation described by the poster exists, it is possible to check the feed gas for the presence of chlorine; if it is present, then the dechlorination agent needs to be replaced. Furthermore, it is also possible to check whether chlorine is present in the crude alcohol fed into the distillation unit; if so, then examine whether chlorine is present in the water quality of the wash tower used after the alcohol treatment.
Thank you for your reply. I’m going to check the chlorine content of the crude alcohol. How can the chlorine content in the feed gas be detected? Thank you!
It’s strange that the chlorine level is so high – is it coal-based methanol?
I would like to ask whether this pure methanol is produced locally or imported from abroad? We have encountered cases where the chloride level in imported chemical products was too high; this was due to the seawater used for cleaning the ships not being thoroughly removed, which led to an elevated chloride content. If it’s produced by oneself, then it’s quite strange.
It is high-purity methanol produced internally. When high-purity methanol is intended for use by premium customers, there are specific requirements regarding the chloride content in the methanol. I saw online a **patent** applied for by the R&D (analysis) staff at Shaanxi Shenmu Chemical Industry Co., Ltd. for a \"Method for Determining Trace Chloride Ions in Methanol\". This also indicates that chloride ions may be present in pure methanol.
Do you mean that the “alcohol post-washing tower” refers to a device for adding alkali? Thank you
It’s likely there’s a problem with the water in the wash tower