Discussion on the mercury content issue in catalysts
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What is the typical mercury content in mercury catalysts used for vinyl chloride synthesis at present? What is the mercury content when the catalyst fails?
We usually carry out failure treatment when the mercury content is 2-3%
The mercury content in the VC synthesis catalyst ranges from 10.5% to 11.5%. When the reaction conversion rate is low, it is necessary to replace the catalyst; its service life is between 5,000 and 8,000 hours, and the mercury content in the spent catalyst is approximately 5%.
Is a compound mercury chloride catalyst being used now?
Does anyone know what the differences are between catalysts in vinyl chloride fluidized bed reactors and those in fixed-bed reactors?
The catalysts used by our company are required to have a mercury content of 10–12%, but in practice, many of these catalysts have a lower mercury content, even those that are new.
In my opinion, the key factors are the conversion rate of the equipment, as well as the reaction temperature and time. Currently, the mercury content in environmentally friendly catalysts is only 4–6%, while it’s around 10–12% for ordinary catalysts
The main difference between the catalyst in a vinyl chloride fluidized bed reactor and that in a fixed bed, as asked on the 5th floor, is: 1. The activated carbon is different (coconut shell carbon)； 2. Different particle sizes (small particle size).
The mercury content is generally around 12%. When it becomes ineffective, it’s not sufficient to consider only the level of mercury content; what’s more important is whether it still has activity, as well as the conversion rate, reaction temperature, and duration of use.