Minimizing Energy Costs Through Water Management in the Pulp and Paper Industry

The quantity of steam required by a pulp and paper mill, as well as the quantity of power generated can effectively be optimized by managing the water cycles in the mill. This approach addresses the process systems within the mill and investigates the unit operations associated with the systems to optimize them. A byproduct of any water reduction program is a reduction in the steam use of the mill. Invariably, this results in an imbalance in the steam distribution, which can require rebalancing the turbogenerators. Process simulation is used to execute the heat and mass balances required at all stages of the analysis. The result is a rapid analysis that pinpoints deficient unit operations and offers a capital spending plan that outlines the necessary process changes. The usual result is a better process with less waste and pollution, improved yield, increased capacity, lower operating costs and reduced energy demands. A case study is presented: a 1990 study that significantly decreases waster usage and allowed additional pulp production while reducing total stream generation and increasing power production