METHOD AND APPARATUS FOR TREATING PULP IN AN INDIRECT HEAT EXCHANGER AFTER PULPING

摘要

The present invention relates to a method of and an apparatus for treating pulp in connection with digesting. The cellulosic material is digested to a kappa number of below 50, the digested pulp is taken at a consistency of 5 20 % to indirect heat exchange means having heat exchange surfaces within the flow means for changing the temperature of the discharged pulp. The pulp is allowed to flow in said indirect heat exchange means at an average velocity of less than 5 m/s. Thus, the pulp is cooled at least 10 ~C in said indirect heat exchange means so that the temperature of the pulp leaving said indirect heat exchange means is 80 to 130 ~C.