Evaluating Brown Stock Washing Mona Henderson, Valmet, Inc.

摘要

Washing is an important factor in the overall performance of a fiberline. The amount of washing required depends on the digester operation e.g. kappa number target and how much chemicals are added as well as what is required downstream to make the process cost-efficient while meeting quality demands of the final product. Many mills in North America have insufficient washing as their washers are dated, inefficient, or too small for the current production rate. At the same time, the demand for optimized performance has increased as mills struggle to remain competitive in the industry. In addition to optimization efforts, many mills are looking at replacing or adding a washing device to their brown stock system. Before the decision to invest is made, the process manager is encouraged to audit the fiberline to establish a baseline of the current performance, run simulations to determine how different solutions will impact the system, and consider physical and operational constraints.This paper reviews the audit process and asks some key questions that must be answered before investing in a new washing device to ensure the maximum benefit from the investment. Examples of optimization efforts as well as the impact of new investments are also shown.