Abstract: Cogeneration of electricity and liquid carbon dioxide is conducted by combusting methane-rich gas to power a gas turbine and a steam turbine; each turbine drives an electric generator. Carbon dioxide is separated from the combustion products by an amine absorption system to which heat for releasing absorbed carbon dioxide is supplied by steam drawn from the steam turbine. Some of that steam is used to produce refrigeration with an ammonia absorption refrigeration unit. The refrigeration is applied to the separated carbon dioxide to liquefy it. Fractionation to yield purified liquid carbon dioxide is easily achieved and saleable refrigeration is another optional product of cogeneration.

Abstract: In refrigeration systems wherein the refrigerant compressor is driven by a prime mover powered by combustion of a fluid fuel, a notable saving in fuel consumption is achieved by utilizing waste heat in the hot exhaust gases from the prime mover in an ammonia absorption refrigeration unit to produce refrigeration in the form of liquid ammonia. Subcooled liquid ammonia is used to subcool the compressed and condensed refrigerant prior to its expansion and evaporation to produce saleable refrigeration. This compound refrigeration system is economically attractive for producing large tonnage refrigeration particularly when a combustion turbine coupled to a centrifugal compressor is used.

Abstract: In refrigeration systems wherein the refrigerant compressor is driven by a prime mover powered by combustion of a fluid fuel, a notable saving in fuel consumption is achieved by utilizing waste heat in the hot exhaust gases from the prime mover in an absorption refrigeration unit that chills a coolant stream circulated to the condenser for the compressed refrigerant. Existing combustion-powered refrigeration systems can be improved by adding a lithium halide absorption unit to utilize heat in the exhaust gases to produce refrigeration that is used to condense the compressed refrigerant. A combustion turbine coupled to a centrifugal compressor is a preferred combination of prime mover and refrigerant compressor for economically producing tonnage refrigeration.

Abstract: Refrigeration is produced while delivering transmission pipeline gas of elevated pressure to a branch pipeline of lower pressure by expanding the gas in a turbo-expander to a pressure below the branch pipeline pressure and recovering refrigeration from the expanded gas which is then compressed by a centrifugal compressor directly driven by the turbo-expander to the pressure required for delivery into the branch pipeline. Preferably, the gas is dehydrated by adding methanol and separating aqueous methanol condensate from the expanded gas, and the condensate is distilled with compression heat to recover methanol for reuse.

Abstract: The high pressure of pipeline gas is reduced to the low pressure of a distribution system with simultaneous generation of refrigeration by passing the gas through two successive centrifugal compressors driven by two turbo-expanders in which the compressed gas is expanded to successively lower pressures. Refrigeration is recovered from the gas as it leaves each turbo-expander. Methanol is injected into the pipeline gas before it is expanded to prevent ice formation. Aqueous methanol condensate separated from the expanded gas is distilled for the recovery and reuse of methanol.