SIMULATION OF MULTIPLE EFFECT EVAPORATOR WITH PROVISION FOR FLASH

Abstract

The present, investigation deals with simulation studies of multiple effect evaporator used for the concentration of kraft black liquor in pulp And paper mills. Finploymentsof condensate flash is included in the analysis. Equations based on material and energy, balances and heat transfer rate are developed for this purpose. GudmundsOn's model is employed for the computation of . ■ over all heat transfer coefficient. these equations are applicable to the black liquor any set of physico-thermal properties. Broyden's method is employed to solve the set of seventeen non-linear algebraic equations developed in the model . A set, of computer programme in FORTRAN77 is developed and executed. The investigation considers variations in input parameters,viz., the feed temperature, feed concentration, live steam temperature, feed rate, and the temperature in the last effect to determine their influence on the steam consumption, steam economy and the heating surface area requirements. Further, the steam consumption, steam economy and the heating area , requirements of the present investigation are compared with those for the case where no condensate flash is employed