(97d) Emissions Reduction Credits and Lost Product Savings: Flare Gas Recovery Provides Numerous Benefits for a Gulf Coast Cracker

As the expansion of shale gas production has resulted in lower feedstock and energy costs in North America, many ethylene producers are looking for ways to increase throughput with debottleneck projects and new plant construction.  One of the key regulatory requirements needed for these projects is the ability to offset volatile organic compound (VOC) emission increases with compensating decreases.

One of the larger sources of VOC emissions in an olefins unit is the continuous release of emissions to the flare stack. The source of these emissions is from process vents, fugitive leaks from pumps and process safety valves, and maintenance clearing activities.  A potentially attractive system for reducing flare emissions is flare gas recovery (FGR), where flare gases are recycled to either fuel or the process instead of being burned at the flare tip.  This paper will detail some of the design considerations for implementing FGR in an olefins unit, as well as some of the specific experiences within Equistar Chemicals, LP where several FGR systems have been installed in the last few years.