Alkali Concentration Control in Cooking Liquor with a New Modular Flow-Through Conductivity Sensor, 2005 Engineering, Pulping & Environmental Conference
Kraft pulping uses strong alkali chemicals to delignify wood chips in a digester. The progress of this reaction can be optimized to maximize the yield of pulp without reducing the strength of the pulp fibers by overcooking. The reaction has traditionally been monitored with periodic chemical titrations (called the ABC tests) that indicate properties of Effective Alkali, Active Alkali, and Total Titratable Alkali. Online monitoring of the pulping liquors, using electrical conductivity, has been shown1,2,3 to provide useful, timely indication of Effective Alkali, but high temperatures and pressures at the process locations make continuous online measurements difficult. Field test results of the latest flow through conductivity sensor indicate that measurement in the recycle line of a batch digester is representative and practical.
Alkali Concentration Control in Cooking Liquor with a New Modular Flow-Through Conductivity Sensor,