restrictions and thecost of fuel promptedmanyflaregas recoveryprojects. The refinery fuel
gas system has become a fertile ground for optimization to ensure that each component
goes to its highest-value disposition. Combining optimization objectives—reducing
overall energy use, recovering hydrogen, and minimizing emissions—can lead to inter-esting projects with robust justifications.
As energy prices soared and refiners investigated energy reduction projects, many
found that their ability to reduce energy consumption was limited by the amount of
refinery fuel gas their plants produced relative to their gas import. As energy-saving
projects were implemented, the amount of marginal import fuel diminished to the point
where the next energy project would result in theflaring of refinery gas (see Figure 20.1).
The economics associated with wasting RFG in aflare, not tomention the environmental
restrictions on flaring, made the incremental energy project wholly unattractive to the
refiner. Therefore, many refiners looked for cost-effective ways to reduce the amount of
fuel gas being produced in the refinery