11:15 - 11:45
Thursday, 19 September 2019
T3.8 Remove Heavy Hydrocarbons from a Comprehensive Range of Feed Compositions
Over the past quarter century, there has been tremendous growth within the LNG industry. Heavy hydrocarbon removal design innovations have accompanied that growth. The industry has experienced a need to process associated gas laden with heavy hydrocarbons, shale and pipeline gas with only a little heavy hydrocarbons, and coal seam gas with almost no heavy hydrocarbons. Each situation presents unique challenges, requiring different design approaches. For a liquefaction facility processing associated gas with large quantities of LPG and NGL components, project economics generally favor an optimized design for high LPG recovery. For pipeline gas, the objective shifts toward removing just enough components to prevent freezing. Even the Curtis Island, Australia LNG facilities that process coal seam methane required a detailed analysis to ensure that no heavies removal system was necessary.
There is no “one-size-fits-all” solution. Designers must address various feed compositions with a suite of design options. One of the most critical decisions of any LNG project is selecting the heavy hydrocarbon removal technology. But, selecting the correct option completely depends on properly quantifying and characterizing the full range of feed compositions. Careful coordination is required between the owner, EPC contractor, and liquefaction technology providers. The design must efficiently and reliably remove enough heavy hydrocarbon components to control the LNG product energy (BTU) content, prevent freezing at all locations within the liquefaction process, and ensure that all LPG and/or NGL products meet specifications.
This paper will present a holistic approach to heavy hydrocarbon removal system designs for LNG liquefaction, beginning with how to properly characterize the feed and ending with a suite of design options that address the wide range of feed gas compositions that may be encountered. Proven design approaches for the unique challenges of processing lean pipeline feed gas through associated gas will be presented.