material to the cellulose recovery process including moisture content temperature of this feed processing temperature dilution of dissolved solids moisture content of discharged cellulose and temperature drop across the heat exchangers in the course of computation it is generally found that the flow of effluent wash water is not the same as the input of fresh wash water since moisture from the solids feed and from steam condensate has been added and moisture in the cellulose output has been subtracted in addition there are the dissolved solids to consider because of all these dependencies an automated system is needed for minute by minute heat exchanger control but set points need first to be calculated in setting up the system calculation begins with mass balances for the hydrothermal wash chamber with reference to fig3 let the flow of fresh wash water into the reaction chamber at 18 be wr and the flow of wash liquor with dissolved solids out of the reaction chamber at 19 be lr the ratio of these two flows is an important determinant of the flash tank pressures so define r wr lr values for wr lr and r must be calculated from the operational requirements of the process application thus start with the feed rate of solid material its temperature and its composition consider the steam flow required.