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.... CJ:) -l.. ..... surfaces developed for the VTE process also be applied to the VC process. The improved tubes have. fluted inside and outside surfaces and are operated with a falling brine film. The overall heat transfer coefficient would be markedly increased, thereby reducing the required heat transfer area. In the past, heat was usually recovered from the brine blowdown and product water in liquid-liqUid heat exchangers. It has recently been proposed that the MSF process be used to recover the heat. This method of heat recovery has the advantage ?f producing added product water. Therefore, the VC plant considered in this report is a combined VC-VTE- MSF plant. The plant uses a vapor compressor driven by a gas turbine and operating across a four-effect vertical tube evaporator, Heat is recovered from the turbine exhaust gas in the form of high and low pressure steam. The high pressure steam is used to generate the required electric power; low pressure steam bled from the power turbine combines with the low pressure steam from the heat recovery boiler and is used to heat the first VTE effect. Heat is recovered from the brine blowdown and product streams in a 24-stage flaSh evaporator. Plant Design The vapor compressor and its driver are the key equipment in the vapor compression process. To avoid excessive design expenses, it is necessary to utilize presently available equipment and operate the com- pressor and driver at their most efficient conditions. The selection of vapor compression equipment for military or marine applications is frequently controlled by the available energy source or requirements for compactness and weight limitations. These relatively small capacity water plants usually use positive displacement blowers driven by electric motors on shipboard and by gasoline engines for field applications. Larger plants in the range of 0.1 to 2 mgd use axial flow compressors 42