Overall heat transfer coefficients in a kraft black liquor industrial evaporation unit. Part Ⅰ - Simulation of multiple effect evaporation system

摘要

To evaluate the overall heat transfer coefficients in a Kraft black liquor industrial evaporation unit, an analysis of the operation performance has been developed with support of WinGEMS 5.3 simulator. Parameters that are not measured directly in the mill, such as the vapor consumption, the liquor solids concentration and the overall heat transfer coefficient for each evaporation body, have been determined by simulation. WinGEMS' evaluation models show an average relative error of 2.4% for the steam consumption and 2.5% for the vapor economy, and these are comparable to the errors expected from industrial measurements.