Recommended Test Procedure for Black Liquor Evaporators

Procedures used to measure the performance of black liquor evaporators and concentrators have frequently produced inconsistent and confusing results. There are two underlying causes for this problem. One is a lack of understanding of how to measure work done by an evaporation system. The second is that no standard evaluation procedure is available. This Technical Information Paper (TIP) establishes recommended test requirements for an accurate evaluation of black liquor evaporators. The evaluations discussed are for maximum rate evaluation, performance evaluation, and troubleshooting. It further describes procedures to fulfill test requirements for each. A general understanding of evaporators and the kraft chemical recovery cycle by the user is assumed. The 2019 textbook Black Liquor Evaporation (1) gives extensive background on evaporators for others. Definitions are listed to ensure common understanding of terms.