Pinch Analysis: A Powerful Tool for the Integration of New Process Equipment Into Existing Pulp and Paper Mills, 2003 Fall Technical Conference

The Weyerhaeuser Company container mill in Albany Oregon has recently switched from a batch to a continuous cooking system. Prior to the installation of the new digester, American Process Inc. performed an energy targeting study for the mill in order to identify the optimum integration of the new continuous digester into the process and to develop practical projects, which will improve the overall energy efficiency of the mill. The tools of simulation and pinch analysis were used, in conjunction with practical mill experience. The simulation model was used to predict the future mill operation including the new digester. A pinch analysis was performed leading to the development of practical heat recovery projects, which can save up to 77 MMBtu/h (~ 15% of the total hot utility usage) in the future mill configuration. These savings are additional to the steam savings realized due to the substitution of the batch with a continuous cooking system. Pinch analysis has proven to be a powerful tool for identifying the best integration of new process equipment into an existing mill, by saving both capital and energy operating costs.