Seeking help regarding the differences between solvent deasphalting
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What is the difference between propane deasphalting and pentane deasphalting? Where are there any plants that use pentane for deasphalting these days?
Due to its low solubility and high selectivity, propane dewaxing is mainly used for producing lubricant base oils; it typically yields three types of products: light dewaxed oil, heavy dewaxed oil, and asphalt. Butane or pentane dewaxing is primarily used to produce cracking feedstocks. The softening point of the dewaxed asphalt can be kept quite high, which helps to increase the overall recovery rate. In China, butane dewaxing and propane dewaxing are the most commonly used methods; pentane dewaxing seems to be less common.
The Nanchong Refinery in Sichuan has an isopropanol deasphalting unit, which is operating quite well.
Apart from the feed on the second floor, another difference between propane deasphalting and pentane deasphalting lies in the recovery system: propane recovery requires a compressor to extract propane from the low-pressure system, whereas pentane does not require one. Propane recovery is carried out through three methods: critical recovery, flash recovery, and stripping recovery, whereas the pentane system relies only on critical recovery and stripping recovery.