PDH Propane Dehydrogenation to Propylene Unit – Feed Propane
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Since domestic propane mainly comes from refinery gas or liquefied gas, it has a low concentration, is stored in dispersed locations, and also has a high sulfur content; therefore, the propane feedstock used in PDH propane dehydrogenation units to produce propylene relies primarily on imports from the Middle East. Imported propane mainly comes from associated gas in oil fields and wet natural gas condensates. The propane in this portion has a high purity and low sulfur content; then why is there about 400 ppm of methanol? To remove methanol, a raw material purification unit must also be installed.
May I ask, where does the methanol in propane come from? Is methanol artificially added when propane is stored in underwater cryogenic tanks to prevent freezing? Otherwise, why should two substances with such a large difference in boiling points, methanol and propane, be combined?
It is likely methanol injected during the liquefaction and cryogenic process to prevent the cold box from freezing up and getting blocked.
Methanol is used to prevent freezing inside; it’s added for that purpose. This doesn’t affect the operation