IsoTherming®
加氢处理技术

As mentioned, the IsoTherming® technology recovers the heat of reaction by recycling a portion of the hot hydrotreated product back to the inlet of the reactor. As such, the feed/effluent exchanger heat duty requirements are reduced, which contributes to a significant reduction in high pressure heat exchanger shells that are required when comparing to an equivalent trickle bed design. Furthermore, separation of hydrocarbon and gas in order to recover the recycle gas is not required with the IsoTherming® process.

Consequently, for typical diesel applications where the hydrogen solubility loss is low, the IsoTherming® process does not necessitate high or low pressure separation vessels and air coolers for the reactor effluent, which can be let down in pressure and sent directly to the stripper or fractionator. For projects with light feeds and low hydrogen consumption, the ability to supply the hydrogen through feed saturation and intermediate resaturation between catalyst beds can sometimes eliminate the recycle pump, resulting in even fewer pieces of high pressure equipment and lower capital costs.

However, in these light-feed applications, higher hydrogen solubility losses may require a cold low-pressure separator for hydrogen recovery to minimize downgrading hydrogen to fuel gas. The separator operates at a pressure that allows the hydrogen-rich gas to undergo amine washing and subsequently be routed to hydrogen recovery via PSA or returned to the makeup-gas compressor. Unlike the large gas-recycle flow in conventional hydrotreaters, this recycle flow is small, representing only a portion of the hydrogen dissolved in the liquid at the reactor outlet.