ECCJ / Text for Training Courses / METI / Energy conservationin Japanese factory(2006.7) / Thailand

ECCJ / Text for Training Courses

Thailand

(case example)
<Successful case in pulp and paper manufacturing>

Optimization of Bleaching Conditions

by “suppon group” at KP section, Jujo Paper Co., Ltd.

Problem to be improved: in Bleaching Process,

variance in brightness
higher unit consumption of steam and chlorine dioxide

<fiber line of kraft pulp>
Wood chip→digester→washers→bleaching process→cleaning→paper machines

Results of “suppon group”s activity

Investigation results:
They were afraid of clogging of the stock pump due to unfamiliarity with the new equipment, so they increased the dilution water gradually. They increased the steam consumption to keep reaction temperature higher. They increased the chemicals consumption to keep reaction rate.
Improvements:
reduced the dilution water step by step, while watching the load of the stock pump; 33 to 6m³/h decreased the steam consumption , to lower the temperature at the steaming mixer; over 70 to 60 results; brightness increased and has kept the standard value. pulp density increased, so the consumption of chlorine dioxide has decreased.
Effect of improvements:
steam reduction: 63t/day chemicals reduction: 27m³/day Merit: 240,000 us$/y

(case example)
<successful case in pulp and paper manufacturing>

Improvement of cleaning method for heat exchanger

By "power supply team A" at engineering dept., sanyo kokusaku pulp co.,ltd.

Problem to be solved:

concerning the heat exchanger in boilersection, the temperature of hot water is getting lower and lower. to be shut down frequently to clean the deposited slime inside of it. ( and to be cleaned with brushes by manpower.) to cause shortage of hot water supply to the pulp treatment line.

Trial implemented by the small group of “team A”

They added sufficient amount of NaOH to the circulating fluid so as to increase pH larger than normal value. (to solve the slime in the heat exchanger)

step1:	pH increased 7 to 9 → → →	temp. of hot water went up by	3^oC
step2:	pH increased to 10 → → →	"	7 ^oC
step3:	pH increased to 12 → → →	"	10 ^oC

Effect of improvements:

increase of heat recovery at the heat exchanger (average temperature up: 8 ^oC) decrease of the oil consumption for heating: 98,000 us$/y
need less of the shut down of the heat exchanger decrease of the steam consumption at the bleaching process: 30,000 us$/y free from the cleaning cost : 137,000 us$/y

12/19
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