PURPOSE: To improve the load followability and the plant efficiency by individually controlling the temperatures of main steam and reheat steam according to burning quantities by using at least two fluidized bed boilers for generating the main steam and the reheat steam.
CONSTITUTION: Feed water absorbs heat by HRHE, is overheated to a predetermined temperature by a vaporizer inserted into a fluidized bed boiler PFBC-A, introduced to a high-pressure steam turbine HP-ST, the steam is further reoverheated by a reheater inserted to a fluidized bed boiler PFBC-B, and introduced to a low-pressure steam turbine LP-ST. A main steam temperature set value is decided by a main steam temperature setter 150, compared with a main steam temperature detected value 704 to obtain a main steam temperature deviation value 153, and a fuel flow rate corrected value 156 is obtained. A fuel flow rate precedence command value 160 and a fuel flow rate corrected value 156 are added by a corrector 162 to become a main steam side fuel flow rate demand 164. On the other hand, a reheat steam temperature control system realizes the control by substantially the same algorithm.
NOMURA MASAHIDE
YAMAMOTO YASUISA
TOYAMA EIJI
BABCOCK HITACHI KK
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