FUEL SUPPLY CONTROLLER

PURPOSE:To keep the quantity of SOx within a prescribed value at all times by inputting the evaporating quantity signal of a boiler and the quantity signal of SOx as compensating values and automatically regulating a mixing ratio to a setting device in which the mixing ratio of high sulfur content fuel and low sulfur content fuel is set. CONSTITUTION:In the case where evaporating quantity is increased by an evaporating signal 11, a mixing ratio setting device 12 sets the mixing ratio of high sulfur content fuel and low sulfur content fuel again and new set value is output to a fuel ratio setting device 5. SOx signals 14 are always output from an SOx quantity detector which monitors the SOx quantity in the combustion exhaust gas of a boiler, and compared with SOx set value. In the case where the SOx signals are out of the range in which the set value is previously determined as a standard thereby, the measured SOx value is output in a substracter 13 as a compensating signal S4, the signals output from the mixing ratio setting device 12 are compensated, and SOx concentration of exhaust gas is within prescribed value.