Pressurized fluidized bed combustion combined cycle power plant and method of operating the same

A power plant said power plant comprising:

• a pressurized fluidized bed combustion boiler means for burning coal and producing steam by combustion heat and including a combustion chamber in which said coal is burned;
• a gas turbine unit including a gas turbine driven by combustion gas from burning of said coal in said boiler means, a spindle rotated at a constant speed by said turbine, an electrical generator driven at a constant speed by said spindle, a compressor means on said spindle for supplying compressed combustion air to said boiler means for burning the coal;
• control means for controlling, in dependence upon an operating load of said boiler means, at least one of a flow rate of said combustion air into said boiler means, and an operating pressure in said combustion chamber of said boiler means, and
• conduit means extending from said compressor means to said boiler means for supplying said compressed combustion air to said boiler means, a booster compressor means for boosting pressure of said combustion air in said conduit means, and drive means for driving said booster compressor means, said control means controlling said drive means so as to effect control of at least one of said combustion air flow rate and said operating pressure.

A power plant comprising a pressurized fluidized bed combustion boiler means for burning coal and producing steam by combustion heat and including a combustion chamber in which said coal is burned;

• a gas turbine unit including a gas turbine driven by combustion gas from burning of said coal in said boiler means, a spindle rotated at a constant speed by said turbine, an electrical generator driven at a constant speed by said spindle, a compressor means on said spindle for supplying compressed combustion air to said boiler means for burning the coal;
• control means for controlling, in dependence upon an operating load of said boiler means, at least one of a flow rate of said combustion air into said boiler means, and an operating pressure in said combustion chamber of said boiler means;
• and
• adjustable vanes for controlling air flow rate into said compressor means, a first conduit means extending from said compressor to said boiler means for supplying said compressed combustion air to said boiler means, a second conduit means extending from said boiler means to said gas turbine for supplying said combustion gas to said gas turbine, and a by-pass means for connecting said first conduit means to said second conduit means, and flow control means for controlling an air flow rate in said by-pass means, and wherein said control means controls at least one of said adjustable vanes and said flow control means of said by-pass means to control at least one of said combustion air flow rate and said operating pressure.

A method of operating a pressurized fluidized bed combustion combined cycle power plant, said power plant comprising a pressurized fluidized bed combustion boiler means for burning coal and producing steam by combustion heat and including a combustion chamber in which said coal is burned, a gas turbine unit including a gas turbine driven by combustion gas from burning of said coal in said boiler means, a single spindle rotated at a constant speed by said gas turbine, an electrical generator driven at a constant speed by said single spindle, a compressor means on said single spindle for supplying compressed combustion air to said boiler means for burning of said coal, said method comprising the steps of:

• operating said power plant, and
• controlling, during operation of said power plant, at least one of a flow rate of said combustion air into said boiler means, and an operating pressure in said combustion chamber of said boiler means in dependence upon the operating load of said boiler means, and wherein said power plant further comprising a conduit means extending from said compressor means to said boiler means for supplying said combustion air to said boiler means, a booster compressor means for boosting pressure of said combustion air in said conduit means and drive means for driving said booster compressor means, and wherein said step of controlling includes controlling said drive means so as to effect control of at least one of said combustion air flow rate and said operating pressure.

A method of operating a pressurized fluidized bed combustion combined cycle power plant, said power plant comprising a pressurized fluidized bed combustion boiler means for burning coal and producing steam by combustion heat and including a combustion chamber in which said coal is burned, a gas turbine unit including a gas turbine driven by combustion gas from burning of said coal in said boiler means, a single spindle rotated at a constant speed by said gas turbine, an electrical generator driven at a constant speed by said single spindle, a compressor means on said single spindle for supplying compressed combustion air to said boiler means for burning of said coal, said method comprising the steps of:

• operating said power plant, and
• controlling, during operation of said power plant, at least one of a flow rate of said combustion air into said boiler means, and an operating pressure in said combustion chamber of said boiler means in dependence upon the operating load of said boiler means, and wherein said power plant further comprises adjustable vanes for controlling an air flow rate into said compressor means, a first conduit means extending from said compressor means to said boiler means for supplying said compressed combustion air to said boiler means, a second conduit means extending from said boiler means to said gas turbine for supplying said combustion gas to said gas turbine, a by-pass means for connecting said first conduit means to said second conduit means, and flow control means for controlling an air flow rate in said by-pass means, and wherein said step for controlling includes controlling at least one of said adjustable vanes and said flow control means of said by-pass means to control at least one of said combustion air flow rate and said operating pressure.

A method of operating a pressurized fluidized bed combustion combined cycle power plant, said power plant comprising a pressurized fluidized bed combustion boiler means for burning coal and producing steam by combustion heat and including a combustion chamber in which said coal is burned, a gas turbine unit including a gas turbine driven by combustion gas from burning of said coal in said boiler means, a single spindle rotated at a constant speed by said gas turbine, an electrical generator driven at a constant speed by said single spindle, a compressor means on said single spindle for supplying compressed combustion air to said boiler means for burning of said coal, said method comprising the steps of:

• operating said power plant, and
• controlling, during operation of said power plant, at least one of a flow rate of said combustion air into said boiler means, and an operating pressure in said combustion chamber of said boiler means in dependence upon the operating load of said boiler means, and wherein the step of controlling at least one of said flow rate of said combustion air and said operating pressure includes controlling an operation of at least two of the following elements:
• a throttle valve controlling air pressure at an inlet of said compressor means,
• vane means for controlling an air flow rate at said inlet of said compressor means,
• a by-pass valve means for controlling an air flow rate from said compressor means to said boiler means,
• drive means of a booster compressor for controlling pressure of air supplied from said compressor means to said boiler means,
• a valve means for controlling a flow through an expansion turbine operated by compressed air from said compressor means,
• a valve means for controlling a flow rate of combustion gas from said boiler means to said gas turbine, and
• a valve means for controlling combustion gas flow from said boiler means to a second gas turbine not mounted on said spindle.

A power plant comprising a pressurized fluidized bed combustion boiler means for burning coal and producing steam by combustion heat and including a combustion chamber in which said coal is burned;

• a gas turbine unit including a gas turbine driven by combustion gas from burning of said coal in said boiler means, a spindle rotated at a constant speed by said turbine, an electrical generator driven at a constant speed by said spindle, a compressor means on said spindle for supplying compressed combustion air to said boiler means for burning the coal;
• control means for controlling, in dependence upon an operating load of said boiler means, at least one of a flow rate of said combustion air into said boiler means, and an operating pressure in said combustion chamber of said boiler means, and wherein said control means includes
• a throttle valve controlling air pressure at an inlet of said compressor means,
• vane means for controlling an air flow rate at said inlet of said compressor means,
• a by-pass valve means for controlling an air flow rate from said compressor means to said boiler means,
• drive means of a booster compressor for controlling pressure of air supplied from said compressor means to said boiler means,
• a first valve means for controlling a flow through an expansion turbine operated by compressed air from said compressor means,
• a second valve means for controlling a flow rate of combustion gas from said boiler means to said gas turbine, and
• a third valve means for controlling combustion gas flow from said boiler means to a second gas turbine not mounted on said spindle and wherein said control means control at least one of said flow rate of said combustion air and said operating pressure by controlling at least two of said throttle valve, said vane means, said by-pass valve means, said drive means, said first valve means, said second valve means and said third valve means.