The Study Of FEP/G-based Heat Conductive Hollow Fiber And Its Heat Exchanger

In the industrial production process, heat exchanger is significant equipment inheat transfer between the materials. The traditional metal heat exchangers have theshortcoming of poor corrosion resistance, poor pollution resistance, high cost andhuge weight. During these decades, as the development of the industry and scientifictechnology, it is significant to have higher performance requirement of the heatexchangers. Common heat exchangers can not meat the demands of some specialareas, such as waste water treatment of chemical industry, Acid and alkali saltcirculation equipment. Therefore, it has huge value of the researching developing theplastic heat exchanger and recent years it has been great developed.The pure plastic heat exchangers have low heat transfer efficiency. In order toimprove the heat conducting property, generally high thermal conductive metal orinorganic filler is used to modify the organic material. This kind of method canprovide great mechanical property and thermal stabilization of the organic heatconductive composite material. With this method, the heat conduction material is lowin price and easy to fabricate and mold. After appropriate fabrication process andformula adjustment, it can replace the metal and is used to some special field.In order to improve the overall effect of heat exchanger and the maximumservice temperature of the plastic heat exchanger, graphite is used as filler and theFEP was mollified with it. In this paper, we make the hollow fiber by compositematerial with small diameter, thin wall and good thermal conductivity. And the heatexchangers are made by the heat conductive hollow fibers.This paper is mainly discussed the formula of the composite material and theinfluences of preparation process on hollow fibers’mechanism and thermal properties.Testing of "water to water" heat exchanging was made by self-made conductivehollow fiber heat exchanger to study the influence and regularity of the heatexchanger performance by changing the fluid process and flux.The study has shown that after adding the graphite into FEP and the low levels ofgraphite have little influence on the thermal stability of the system. Adding thegraphite into FEP improves the structure of cross section, makes it smoother and combines graphite and FEP closer. When graphite content is less than10%, as theincrease of the graphite content, the tensile strength of the FEP/G composite materialhollow fibers increases and10%reaches the supreme. When more than10%, as itincreases, the tensile strength decreases.Through the "water to water" testing of heat exchanger, to some extent, addinggraphite has positive influence on heat transfer performance of FEP conductivehollow fiber. When the graphite content is below5%, the heat transfer effect changeslittle. When increasing to7%~10%, the heat transfer effect of heat exchanger hasincreases a lot. Appropriately improving the fluid flux is better for heat transfer effectof heat exchanger. As the hot fluid flows in the shell of the exchanger, best heattransfer effect can be reached by fixing the flux of cold fluid in pipe and raising thethermal fluid flow in the shell. The hollow fiber has thicker wall, the higher thermalresistance and this make the whole heat transfer effect reduced. During the text of theheat exchanger, the thermal conductivity of unit area reaches127.7~621.1W/(m~2K),and the thermal conductivity of unit volume2.46×10~4~1.40×10~5W/(m~3K).The result shows that the heat exchangers made by FEP with graphite compositehas low cost, light weigh, easy installation and transporting. They have thermalconductive material high fill rate per unit volume and great heat exchangeperformance.