Q & A > Question Details
What are the effects of excess recycle gas flow with high purity at 95+ vol% on a hydrotreater unit? It's good for the catalyst but what are its effects on the process, especially on the furnace?
22/06/2020 A: Jake Gotham, InSite Technical Services, jake.gotham@insitetechnical.com
Excessive recycle gas flow is an energy cost. Energy consumption will be higher in the furnace and recycle compressor. It will also increase the system pressure drop which might reduce the processing capacity. In extreme cases, you could also have corrosive velocities in the reactor effluent air-cooler tubes, tube vibration in the feed/effluent exchangers or flooding in the recycle gas amine scrubber (if there is one). Another hidden risk is that the higher system pressure drop may make it possible for the pressure at the front end of the unit (exchangers or furnace) to exceed design pressure while the relief valve at the back end of the system (separator or compressor knock-out drum) is below set-pressure.