Since the oil shock in autumn, 1973, energysaving has become one of the biggest projects in the pulp and paper industry in Japan.
Many energy saving plans are now in the process being introduced into our company also. The ESPAD preevaporator system which was installed at Nomachi mill, Takaoka-City, as one of the energy saving project, was started up successfully in February, 1982.
This report is the summary of the operation. This system consists of 2 stages of plate-type evaporator manufactured by SHI, and is located between the flush cyclone and the relief gas condenser.
The steam from the flush cyclone where the extracted black liquor from Kamyr continuous digester is flushed, is led to the preevaporator and the extracted liquor is concentrated as dense as 2 percent, in the solid base, prior to being sent to the main evaporator. The vapor condensate from the flush cyclone is separated between highly contaminated liquor, high B. O. D liquor, and the low one ; therefore this system minimizes the treatment of contaminated liquor at the stripping stage.
