Evaporation System Solutions-Energy and the Environment

摘要

Evaporator technology has developed to improve the energy efficiency and environmental performance of the mill. To optimize evaporator plants, it is important to evaluate the "life cycle cost" (LCC). A low LCC includes optimized energy solutions, high availability and positive impacts on the environment, especially air and water. Energy optimization requires that fuel price, electricity price and fuel self sufficiency be evaluated using the mills internal evaluation parameters in a LCC analysis.Evaporation plants can be designed to improve the environmental performance of the recovery boiler by producing higher firing solids and creating less variation in the firing solids. Overall Methanol removal in the evaporators can be improved by liquor and vapor flow configuration to improve condensate segregation, efficiently integrated condensate treatment systems, and reprocessing intermediate condensate inside of falling film evaporators. Measured overall Methanol removal efficiencies of 97-98% have been obtained in modern evaporator plants. Evaporation of various mill effluent streams can also improve the environmental performance of the recovery island. Mill experience with a nine effect system that improved both the energy and environmental performance of a European mill will be reviewed. Other mill experiences from solutions generated in LCC analyses that improved both environmental performance and energy efficiency are also discussed.