Replacement of Joule-Thomson valves by two-phase flow turbines in industrial refrigeration applications

Many industrial processes produce low temperature liquefied gases by expanding liquid and gas through a Joule-Thomson valve. Included processes are propane refrigeration, ethylene, propylene and LNG production, air separation, and other cryogenic applications. Substitution of two-phase flow turbines for Joule-Thomson valves generates power from previously wasted two-phase expansion energy. Expansion in a turbine nozzle reduces frictional dissipation and results in the production of additional cold liquid. Plant capacity increases for a fixed compressor and heat exchanger installation, or compressor power and heat exchanger size decreases for a given plant capacity. In addition processes are simplified with elimination of pre-chillers and heat exchangers. Performance of a commercial refrigeration turbine is compared to performance code predictions to confirm validity of the model. Performance estimation and the result of two-phase turbine application to several processes are presented. In addition, major areas of application for Joule-Thomson valve replacement are identified.