CROSS FLOW FILTRATION OF GREEN LIQUOR FOR INCREASED PULP PRODUCTION, IMPROVED GREEN LIQUOR QUALITY, AND ENERGY SAVINGS

摘要

A new green liquor filtration system has been installed and commissioned at the Ence pulp mill in Pontevedra, Spain. The filtration system is based on microftltration and was developed in collaboration with the KTH Royal Institute of Technology in Stockholm, Sweden. The patented method for efficient purification of green liquor decreases the NPE content by providing more efficient solids/liquid separation, reducing energy and chemical consumption in pulp mills, and could lead to increased production capacity by eliminating certain capacity bottlenecks. The process has been tested at the Aspa Bruk Mill outside Askersund Sweden continuously since 2013. The technology has proven to create nearly paniculate free green liquor during the purification process. The technology can also be used to polish white liquor to provide higher pulp quality. To provide for a simple cost-effective installation, the system was designed as a skid mounted unit pre-piped, instrumented, and tested before shipment. The system is modular and allows for easy expansion of capacity. This paper discusses the process design, process integration, and startup of the new system, along with experiences for the first months of operation.