Pinch Integration Achieves Minimum Energy Evaporation Capacity, 1996 Engineering Conference Proceedings

H. R. Cripps (HRC Consultants Ltd)

A. W. Melton (Alabama River Pulp)

T. Retsina (American Process Inc.)

R. Capell (American Process Inc.)

Cooperation between equipment suppliers, operating mill personnel and engineering consultants provided the Alabama River Complex with new evaporation capacity for a minimal increase in overall steam requirement. The energy integration was specified after a pinch analysis had identified optimum thermal placement of evaporation plant, and determined the most appropriate driving energy source and heat rejection sinks. Additional evaporation capacity of 420,000 lb/hr was achieved by designing a 5 effect pre-evaporation train driven by vapor from the continuous digester flash system. The pre-evaporator condensers supply heat for the original hot water requirements, and also satisfy a bleach plant white water heating duty previously carried out with steam. The train uses only an extra 55,000 lb/hr of fresh process steam in parallel with the flash vapor, and almost all of this additional heat is usefully recovered. A highly advantageous steam economy has been achieved through appropriate placement; 420,000 lb/hr of extra evaporation was achieved with an increase in site steam demand of only 10,000 lb/hr. This was made possible by the use of pinch technology, innovative thinking, and close cooperation of all parties involved...