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the ocean. The remainder of the cooling water is treated with acid, deaereated, ana then preheated by passing through the MSF section. ~ ~ There are three flash stages for each VTE effect, and brine is en ~, pumped from the last stage in each series to the top of the VTE effect operating at the same temperature. The brine enters the top of the fluted tubes through swirl orifice nozzles, which regulate the flow and direct the brine against the tube surface. Part of the brine is evaporated inside the tube and the rest flows back to the MSF section, where it is flashed in succeeding stages and condensed by the incoming feed stream. The vapor formed inside the VTE tubes is separated from the brine below the tube bundles and is condensed on the outside of the next lower pressure evaporator effect to form the product water stream. The product water flows to the MSF section and is flashed to heat the feed stream. On the basis of the operating conditions and design selected for the reference VTE-MSF plant, the required investment and annual operating costs of a 10- and 50-mgd plant were estimated. These results are given in Tables lOA and B and are summarized with desalting costs in Table 11. Analysis of the VTE-MSF Process Analysis :of the costs in Tables lOA, lOB, and 11 for the 50-mgd LTV-MSF process indicate that 80 percent of the desalting costs are the result of energy requirements and equipment amortization. The energy requir~ments account for 54 percent of the water production cost and are divided between 49 percent for steam and 5 percent for electric power. The evaporator (shell and tubes only) is 55 percent of the plant investment and amortization of the depreciable plant investment accounts for 26 percent of the desalting cost. Amortization of the shells, VTE tubes, and MSF tubes are 6.4, 5.8, and 2 percent, respectively, of 31