| 摘要 |
PURPOSE:To perform heat recovery by one heat exchanger, by a method wherein conc. sludge is charged in the first digestion tank of each system after passed through the low temp. side of a heat exchanger and the digested sludge is subsequently passed through the high temp. side of said heat exchanger before distributed to the second digestion tank of each system. CONSTITUTION:Conc. sludge passes a conc. sludge pipeline 9 and an A-system conc. sludge pipeline 9a through a heat exchanger 4 and charged into an A-system first digestion tank 1a. At this time, only a transfer sludge withdrawal and change-over valve 17b is opened and only a transfer sludge charging and change- over valve 18b is opened while the sludge in a B-system first digestion tank 1b is charged in a B-system second digestion tank 2b by a transfer pump 3 through the heat exchanger 4. That is, the heat source for heating conc. sludge charged in the A-system first digestion tank 1a is obtained from the transfer sludge from the B-system first digestion tank 1b and the charging and transfer of conc. sludge in the same system are not performed simultaneously. The charging to B and C systems is also performed similarly.
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