Abstract:
Contemplated plants include a NGL recovery portion and a LNG liquefaction portion, wherein the NGL recovery portion provides a low-temperature and high-pressure overhead product directly to the LNG liquefaction portion. Feed gas cooling and condensation are most preferably performed using refrigeration cycles that employ refrigerants other than the demethanizer/absorber overhead product. Thus, cold demethanizer/absorber overhead product is compressed with the turbo-expansion and delivered to a liquefaction portion at significantly lower temperature and higher pressure without net compression energy expenditure.
Abstract:
Contemplated plants and methods for NGL recovery from feed gases having a carbon dioxide content equal or greater than about 2% employ temperature control configurations that allow high-level and flexible recovery of ethane and heavier components while avoiding freezing of the carbon dioxide in the process. Where the feed gas has a significant fraction of C3+ components and moderate carbon dioxide content, a single column configuration with an intermediate reflux condenser may be used, while two-column configurations may be used for feed gases with high carbon dioxide content and relatively low C3+ component concentration.
Abstract:
Acid gas is removed from a feed gas using a physical solvent that is regenerated using successive flashing stages after heating of the rich solvent using low-level waste heat that is preferably produced or available within the acid gas removal plant. Especially preferred waste heat sources include compressor discharges of the refrigeration system and/or recompression system for CO2, and/or (low level) heat content from the feed gas.
Abstract:
Contemplated plants for recovery of NGL from natural gas employ alternate reflux streams in a first column and a residue gas bypass stream, wherein expansion of various process streams provides substantially all of the refrigeration duty in the plant. Contemplated plants not only have flexible recovery of ethane between 2% and 90% while recovering at least 99% of propane, but also reduce and more typically eliminate the need for external refrigeration.
Abstract:
A sulfur species-containing feed gas is processed in a treatment plant in which COS is hydrolyzed, and in which so produced hydrogen sulfide and other sulfur species are absorbed in a lean hydrocarbon liquid. The sulfur species in the so formed rich hydrocarbon liquid are then subjected to catalytic conversion into disulfides, which are subsequently removed from the rich solvent. Most preferably, sulfur free lean solvent is regenerated in a distillation column and/or refinery unit, and light components are recycled from the rich hydrocarbon liquid to the absorber.
Abstract:
Contemplated configurations and methods use first and second precoolers, preferably in alternating operation, to provide a combustion turbine with air at a temperature of 50 °F, and more typically less than 32°F and most typically less than 0'F. In such configurations and methods it is generally preferred that a heat transfer fluid circuit provides both, heated and cooled heat transfer fluid to thereby allow cooling and deicing of the precoolers. Most preferably, refrigeration is provided from an LNG regasification unit to form the cooled heat transfer fluid while heat from a power cycle (e.g., from surface condenser) is used to form the heated heat transfer fluid.
Abstract:
Acid gas is removed from a high pressure feed gas that contains significant quantities of CO2 and H2S. In especially preferred configurations and methods, feed gas is contacted in an absorber with a lean and an ultra-lean solvent that are formed by flashing rich solvent and stripping a portion of the lean solvent, respectively. Most preferably, the flash vapors and the stripping overhead vapors are recycled to the feed gas/absorber, and the treated feed gas has a CO2 concentration of less than 2 mol% and a H2S concentration of less than 10 ppmv, and more typically less than 4 ppmv.
Abstract:
Contemplated plant configurations and methods employ a vaporized and supercritical LNG stream at an intermediate temperature that is expanded, wherein refrigeration content of the expanded LNG is used to chill one or more recompressor feed streams and to condense a demethanizer reflux. One portion of the so warmed and expanded LNG is condensed and fed to the demethanizer as reflux, while the other portion is expanded and fed to the demethanizer as feed stream. Most preferably, the demethanizer overhead is combined with a portion of the vaporized and supercritical LNG stream to form a pipeline product.
Abstract:
Contemplated configurations and methods employ COS hydrolysis and a downstream H2S removal unit to produce a treated feed gas that is then further desulfurized in an absorber using two lean oil fluids. The so produced mercaptan enriched hydrocarbon fluid is fed to a distillation column that produces a light overhead vapor that is preferably combined with the treated feed gas and a sulfur rich bottom product that is in most cases preferably directly fed to a hydrocarbon processing unit comprising a hydrotreater. In further especially preferred aspects, the hydrocarbon processing unit produces at least one and more typically both of the two lean oil fluids, and the treated gas is optionally further processed to produce clean fuel gas in a hydrotreater for olefinic saturation and sulfur conversion using a lean oil recycle for reactor temperature control.
Abstract:
Contemplated methods and configurations use a cooled ethane and CO2-containing feed gas that is expanded in a first turbo-expander and subsequently heat-exchanged to allow for relatively high expander inlet temperatures to a second turbo expander. Consequently, the relatively warm demethanizer feed from the second expander effectively removes CO2 from the ethane product and prevents carbon dioxide freezing in the demethanizer, while another portion of the heat-exchanged and expanded feed gas is further chilled and reduced in pressure to form a lean reflux for high ethane recovery.