FLUIDIZED BED FOR PREVENTION OF FREEZING IN CRYOGENIC HEAT EXCHANGERS

A SERIOUS PROBLEM IN HEAT EXCHANGERS WHERE ATMOSPHERIC AIR IS COOLED TO CRYOGENIC TEMPERATURES IS THAT THE AMBIENT WATER VAPOR AND CO(2) FREEZE ONTO THE HEAT TRANSFER SURFACES. AS THE SOLID DEPOSITS ACCUMULATE THEY ADVERSELY AFFECT PERFORMANCE BY DECREASING HEAT EXCHANGER EFFECTIVENESS AND INCREASING PRESSURE DROP. AN INNOVATIVE APPROACH FOR DEALING WITH THE FREEZING PROBLEM WHICH OFFERS SIGNIFICANT POTENTIAL ADVANTAGES OVER CONVENTIONAL TECHNIQUES IS THE USE OF A FLUIDIZED BED HEAT EXCHANGER. AN EXPERIMENTAL AND ANALYTICAL PROGRAM IS PROPOSED TO INVESTIGATE THE TECHNICAL FEASIBILITY OF IMPLEMENTING THIS CONCEPT IN CRYOGENIC APPLICATIONS. PARAMETRIC TESTS WILL BE CONDUCTED ON LABORATORY-SCALE MODELS TO OBTAIN DETAILED EXPERIMENTAL DATA ON THE KEY TECHNICAL ISSUES RELATIVE TO THE APPLICABILITY OF THE CONCEPT. ANALYSIS AND CORRELATION OF THE TEST RESULTS WILL PROVIDE A DEFINITIVE ASSESSMENT OF FEASIBILITY AND WILL IDENTIFY THE SPECIFIC DEVELOPMENT REQUIREMENTS FOR EVENTUAL FULL-SCALE IMPLEMENTATION.