Refrigeration method and installation using parallel refrigerators/liquefiers

Abstract

An installation for refrigerating a same application by means of a single refrigerator/liquefier or several refrigerators/liquefiers arranged in parallel, the refrigerator(s)/liquefier(s) using a working gas of the same type having a low molar mass, each refrigerator/liquefier comprising a compression station to compress the working gas, a cold box intended for cooling the working gas at the outlet of the compression station, the compression station comprising only compression machines of the lubricated screw type and systems for removing the oil from the working fluid at the outlet of the compression machines, and the compression station comprises a plurality of compression machines defining several levels of pressure for the working fluid, the compression station comprising at least two compression machines defining at least two levels of pressure increasing above the level of pressure of the fluid at the inlet of the compression station, two main compression machines being arranged in series and defining, at their respective fluid outlet, levels of pressure respectively called 'low' and 'high', another secondary compression machine being supplied at the inlet with a fluid coming from the cold boxes at an intermediate level of pressure called “medium” between the low and high levels, this secondary compression machine also defining, at its fluid outlet, a “high” level of pressure.