Profitably Recover Ngls, Hydrogen and Ethylene/Propylene From Refinery Fuel Gas

Over decades of operation, refinery fuel gas systems have become the repository for purge gases from Fluidized Catalytic Cracking, Delayed Coking, Catalytic Reforming, Hydrotreating and Hydrocracking process units. Flare gas recovery systems also contribute to the build-up of non-methane components in refinery fuel gas.  Hydrogen concentrations of 50 volume per cent (and higher) are not unusual.  Extracting hydrogen, NGLs and ethylene/propylene from the fuel gas system offers provides a moderate capital cost route to improved profitability, triggered by the “perfect storm” conditions  of low natural gas cost (to replace the heating value of extracted gases) and higher values for recovered components.

Technology options for extraction and purification include cryogenic (propane refrigeration, turbo expander, etc.), pressure swing adsorption (PSA), semi-permeable membranes, compression and gas treating.  BHTS has developed optimized configurations utilizing a combination of technologies to meet a refiner’s specific recovery and purity targets.

An initial screening study provides in-depth understanding of the current operation and identifies opportunities for segregation, extraction, treating and purification of hydrogen, NGLs and propylene fractions of various streams connected to the fuel gas system.  This is followed by a comprehensive analysis which includes capital & operating cost estimating, equipment location, piping changes and utility / offsites impacts.