An indirect freeze concentration system operating in accordance with a reversibleheat pump cycle includes a first tube-tube heat exchanger  and a second tube-tube heat exchanger . Heat exchange between a selectively supplied feed stream and a low pressure low temperature refrigerant enables a solvent from the feed stream to freeze within the first tube-tube heat exchanger  while vaporizing the low pressure low temperature refrigerant . A first compressor  receives and compresses the low pressure vapor refrigerant  to an intermediate pressure . Heat exchange between a pre-formed frozen solvent and the intermediate pressure refrigerant within a second tube-tube heat exchanger melts the frozen solvent and partially condensing the intermediate pressure refrigerant. A second compressor  receives and compresses the vapours  of the partially condensed intermediate pressure refrigerant  to a high pressure refrigerant . Heat of the high pressure refrigerant  is rejected to ambient temperature to obtain a condensed refrigerant  which is re-circulated to the first tube-tube heat exchanger

Indian patent application no. 1915/MUM/2010

Inventors: M V Rane, Yogesh S. Padiya