Pulverized-fuel supply unit and method, and integrated gasification combined cycle
A pulverized-fuel supply unit includes a hopper, first nozzles, second nozzles, a pressurizing-gas supply device, a fluidization-gas supply device, and a pulverized-fuel supply line. The hopper has a hollow to store therein pulverized fuel. The first nozzles are provided to the hopper. The second nozzles are provided to a vertically lower part of the hopper below the plurality of first nozzles. The pressurizing-gas supply device is configured to supply pressurizing gas to increase internal pressure of the hopper. The fluidization-gas supply device is configured to supply fluidization gas to fluidize the pulverized fuel in the hopper. The pulverized-fuel supply line is provided to a vertically lower part of the hopper. The pressurizing-gas supply device supplies pressurizing gas to the first nozzles and the second nozzles. The fluidization-gas supply device supplies fluidization gas to the second nozzles.
1. A pulverized-fuel supply unit comprising:
a hopper having a hollow shape to store therein pulverized fuel;
a plurality of first nozzles provided in the hopper at a first position in a vertical direction of the hopper;
a plurality of second nozzles provided in the hopper at a second position in the vertical direction, the second position being lower than the first position;
a pressurizing-gas supply device configured to supply pressurizing gas to increase internal pressure of the hopper;
a fluidization-gas supply device configured to supply fluidization gas to fluidize the pulverized fuel in the hopper; and
a pulverized-fuel supply line provided to the hopper at a third position in the vertical direction, the third position being lower than the second position, wherein
the pressurizing-gas supply device supplies pressurizing gas to the plurality of first nozzles and the plurality of second nozzles,
the fluidization-gas supply device supplies fluidization gas to the plurality of second nozzles,
the plurality of first nozzles are arranged at predetermined intervals in a circumferential direction of the hopper, and
the plurality of second nozzles are arranged at predetermined intervals in the circumferential direction.
2. The pulverized-fuel supply unit according to claim 1 , wherein a flow rate of gas supplied by the fluidization-gas supply device is lower than a flow rate of gas supplied by the pressurizing-gas supply device.
3. The pulverized-fuel supply unit according to claim 1 , wherein
the hopper includes a body portion that has a cylindrical shape and a closed upper end; a cone portion that is coupled to a vertically lower part of the body portion and tapers vertically downward; and a chamber portion that is coupled to a vertically lower part of the cone portion and has a closed lower end.
4. An integrated gasification combined cycle comprising:
the pulverized-fuel supply unit according to claim 1 to supply pulverized fuel obtained by pulverizing carbonaceous feedstock;
a gasification unit configured to gasify the pulverized fuel supplied from the pulverized-fuel supply unit to generate flammable gas;
a gas clean-up unit configured to remove impurities from the flammable gas generated by the gasification unit to clean the flammable gas;
a gas turbine unit configured to burn mixed gas of compressed air and at least part of the flammable gas cleaned by the gas clean-up unit to rotate and drive a turbine;
a heat recovery steam generator configured to generate steam by using flue gas from the gas turbine unit; and
a steam turbine unit configured to rotate and drive a turbine by using the steam generated by the heat recovery steam generator.
5. A pulverized-fuel supply unit comprising:
a hopper having a hollow shape to store therein pulverized fuel;
a plurality of first nozzles provided in the hopper at a first position in a vertical direction of the hopper;
a plurality of second nozzles provided in the hopper at a second position in the vertical direction, the second position being lower than the first position;
a pressurizing-gas supply device configured to supply pressurizing gas to increase internal pressure of the hopper;
a fluidization-gas supply device configured to supply fluidization gas to fluidize the pulverized fuel in the hopper; and
a pulverized-fuel supply line provided to the hopper at a third position in the vertical direction, the third position being lower than the second position, wherein
the pressurizing-gas supply device supplies pressurizing gas to the plurality of first nozzles and the plurality of second nozzles,
the fluidization-gas supply device supplies fluidization gas to the plurality of first nozzles and the plurality of second nozzles, and
the pulverized-fuel supply unit includes
a controller configured to cause the fluidization-gas supply device to stop injection of fluidization gas from the plurality of first nozzles when the amount of the pulverized fuel in the hopper decreases below a predetermined lower limit during conveyance of pulverized fuel from the hopper.
6. The pulverized-fuel supply unit according to claim 5 , wherein
the fluidization-gas supply device includes a fluidization-gas supply line; a first fluidization-gas supply line that branches off from the fluidization-gas supply line and is connected to the plurality of first nozzles; a first open/close valve provided to the first fluidization-gas supply line; a second fluidization-gas supply line that branches off from the fluidization-gas supply line and is connected to the plurality of second nozzles; and a second open/close valve provided to the second fluidization-gas supply line, and
the controller opens the first open/close valve and the second open/close valve when the amount of the pulverized fuel in the hopper is equal to or larger than the lower limit, and closes the first open/close valve when the amount of the pulverized fuel in the hopper decreases below the lower limit.
7. A pulverized-fuel supplying method performed in a pulverized-fuel supply unit that includes a hopper having a hollow shape to store therein pulverized fuel; a plurality of first nozzles provided in the hopper at a first position in a vertical direction of the hopper; a plurality of second nozzles provided in the hopper at a second position in the vertical direction, the second position being lower than the first position; a pressurizing-gas supply device configured to supply pressurizing gas to increase internal pressure of the hopper; a fluidization-gas supply device configured to supply fluidization gas to fluidize the pulverized fuel in the hopper; and a pulverized-fuel supply line provided to the hopper at a third position in the vertical direction, the third position being lower than the second position, the pressurizing-gas supply device supplying pressurizing gas to the first nozzles and the second nozzles, the fluidization-gas supply device supplying fluidization gas to the second nozzles, the method comprising:
activating the pressurizing-gas supply device to apply pressure into the hopper; and
activating the fluidization-gas supply device to convey the pulverized fuel from the hopper,
wherein the plurality of first nozzles are arranged at predetermined intervals in a circumferential direction of the hopper, and
the plurality of second nozzles are arranged at predetermined intervals in the circumferential direction.