How to use TDS measurements to evaluate the performance of diffuser washers - mill study

摘要

Various types of pulp washing equipment are available. Each washing device has a unique mechanical construction, and the washing principle is often a combination of dilution thickening and displacement washing. In this work, the performance of the pressure diffuser, the washing operation of which is based on liquor displacement, is studied. Diffuser washing occurs normally at a medium consistency (10-12%). In the stepwise trials, the effect of the feed and discharge consistencies on the performance of diffuser was studied. The effect of the downward velocity of the screen on the pressure diffuser's washing efficiency was also studied. The measurement of total dissolved solids (TDS) by a process refractometer was used as the wash loss measurement unit and the refractometer's results were used in the E-value calculations. The COD and conductivity were also measured and their results compared to the TDS results. The results indicated that feed consistency has a significant effect on the performance and effectiveness of the diffusers in the experimental mill. It can also be stated that when the downward velocity of the screen is adjusted to too high a level, the washing efficiency of the pressure diffuser weakens. As a conclusion from the mill test, it can be stated that even small process parameter changes can provide enhanced diffuser washing at the beginning of the washing line, and this has a direct effect on the performance of the post-oxygen washing.