Design Development of Fluropolymer Spiral Tube Heat Exchanger

Abstract

In process industry there is always a need of chemically inert and non corrosive heat exchangers , although the conventional heat exchangers made from copper, aluminium and other metallic materials seldom prove useful in these cases.  Polymeric materials heat exchangers although chemically inert , but lack the thermal capabilities suitable to heat exchangers. The only polymeric heat exchangers to offer modest heat transfer abilities are the fluropolymer heat exchangers Another dominant problem in the heat exchangers is that of fouling  as the condensate substrates are deposited on the conductive  surfaces or wetted perimeter area of the tubes. As a result of fouling the heat transfer rate and  overall effectiveness of the heat exchanger comes down considerably . Heat exchangers applied  in process industry , food industry,  chemical industry and medical field applications require special  inert or non reactive materials for the tubes so that there is no  possibility  of contamination  and  low level of scale and fouling.  Owing to its geometry the spiral tube in tube heat exchangers are compact in design ,  although  high on the pumping power .  The  fluro polymer spiral tube in tube heat exchanger design is  selected for the development purpose with the view of producing a compact , chemically inert heat exchanger  . The approach in the design and development is to deal with the  problem of fouling at two levels as proposed in this paper  , namely selection of  an suitable material to prevent fouling and scaling issues and secondly to add  a innovative geometry variation  in the form of  pitch augmentation where in the flat shape geometry of the spiral can be converted to an  to a conical frustum. The Fluropolymers exhibit modest thermal capabilities but excellent resistance to corrosion . The paper discuses the application of fluropolymer in spiral tube in tube form for application as a condensor in ditallation of lemon grass oil used for medicinal purpose.