JPS58128422A - Method and equipment for generating electricity with solid fuel - Google Patents

Abstract

PURPOSE:To lengthen the lifetime of a dust collector, by using a pressurized fluidized bed combustion furnace, mixing combustion gas coming out of the fluidized bed of he furnace, with some of low-temperature combustion gas flowing to a chimney, to cool the former combustion gas, and thereafter removing the mixed combustion gas of dust. CONSTITUTION:A solid fuel and a fluidizing medium (lime) are supplied from a feeder 1 into a fluidized bed combustion chamber 2 in which the solid fuel is burnt. Some of the fluidizing medium, which has come into the combustion gas, is removed by a dust collector 3. Burning air is pressurized by a compressor 5 and supplied into the combustion chamber 2. In order to cool the combustion gas from the combustion chamber 2 before the gas enters into the dust collector 3, some of the combustion gas flowing to a chimney 13 is taken out of a gas ramification pipe 11 and compressed by a gas compressor 6 and then conducted into a mixer 12 in which the combustion gas is cooled to a prescribed temperature. After the combustion gas removed of dust is heated by a heat exchanger 7, the gas is caused to perform work on a gas turbine 8 to drive an electricity generator 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for generating power or electric power from solid fuel using a pressurized fluidized bed combustion furnace.

A method of generating electricity using a pressurized fluidized bed combustion furnace involves removing dust from the combustion gas coming out of the fluidized bed using a dust removal device.
Although there are methods for supplying high-temperature gas to a gas turbine plant, removing high-temperature gas causes a significant shortening of the life of the dust removal equipment. An object of the present invention is to provide a gas turbine power generation method with improved dust removal and piping system.

The method of generating electricity from solid fuel according to the present invention is to burn the solid fuel in a fluidized bed, add some of the gas discharged to the chimney to the generated high-temperature gas, and adjust the gas temperature to a temperature suitable for the dust removal device. It is characterized by adjusting the gas mixture to the maximum temperature, removing dust from the mixed gas, reheating it, and sending it to the gas turbine. When using a reheated dust remover, it is desirable to set the temperature of the mixed gas to 450°C when it enters the dust remover.

The temperature of the combustion gas coming out of the fluidized bed is 1370"C,
450' (to be 8) by mixing low-temperature combustion gas
Requires low-temperature combustion gas that is 8 times or more by weight compared to the combustion gas flow rate at 0°C.◎As the temperature of low-temperature combustion gas increases, a larger gas flow rate is required.

This is the amount of combustion gas for the required air current. Therefore, as long as the gas temperature when the low-temperature combustion gas is compressed by the gas compressor is lower than the temperature of the combustion gas before being reheated, it can be used. The temperature of the low-temperature combustion gas mixed with the combustion gas discharged from the bed must be kept low to some extent.

That is, the combustion gas discharged from the gas turbine may be sent to the recuperator, and a portion of the low-temperature combustion gas exiting the recuperator may be mixed with the combustion gas exiting from the fluidized bed.

If it is necessary to remove the Box and soot contained in the combustion gas leaving the recuperator through a desulfurization device,
A part of the combustion gas that has passed through the desulfurization device can be mixed with the high-temperature combustion gas. Using this method, the life of the heat exchanger and gas turbine that reheat the mixed gas can be extended,
Although there is an advantage that the gas compressor required to compress the combustion gas can be made smaller, there is also a disadvantage that the retained heat of the combustion gas cannot be used effectively. 'Which of these two methods is selected depends on the properties of the solid fuel, and the scope of the present invention includes both of them.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

The drawing shows an embodiment of the invention, in which solid fuel and fluidized medium (lime) are fed into a feeder (through υ and into a fluidized bed combustion chamber @). The solid fuel is burned at a temperature of approximately 870°C. The added fluidizing medium (lime) serves to remove the sulfur content from the fuel and as a fluidizing medium; a portion enters the combustion gas and is removed by the dust removal device (3), and a portion is removed from the fluidizing medium discharge pipe. It is removed from (4).

Combustion air is compressed to an appropriate pressure by an air compressor (6) and sent to the fluidized bed combustion chamber (g).

(6) to compress the combustion gas to an appropriate pressure, and in addition to the combustion gas of about 8 ℃, the mixed gas in the gas mixer (b) is heated to 4 volumes.
Adjust the temperature to 50°C. The mixed gas is removed through the dust removal device (3) and sent to the heat exchanger (7).

The mixed gas is reheated by a heat exchanger to approximately 1350"c and sent to the gas turbine (8). To enable part-load operation of the gas turbine, a portion of the mixed gas is not reheated and is sent to the gas turbine (8). A branch pipe (9
) will be established. The reheated mixed gas is passed through a gas turbine (8
), air compressor 41 (5), gas compressor (6
), drive the generator (b). The expanded gas is sent to the recuperator αQ, where heat is recovered and then the chimney θ
8), but a part of it is returned to the gas compressor (6) through the gas branch pipe 0η.

If there is surplus heat power remaining in the combustion chamber in the above combustion gas flow, this surplus heat can be extracted by a water or steam heat exchanger immersed in a fluidized bed, and the combustion leaving the recuperator When the gas is passed through the desulfurization device, a portion of the combustion gas after desulfurization is returned to the gas compressor or discharged from the gas turbine, and the scope of the present invention is not limited to such an embodiment.

As is clear from the above description, although the present invention has the disadvantage of requiring a combustion gas compressor, it is also effective in gas turbine plants using solid fuel by reheating the gas even after cooling it to a temperature range suitable for the dust removal device.

[Brief explanation of the drawing]

FIG. 1 relates to one embodiment of the present invention, and is a flow diagram of a solid fuel combustion gas turbine plant that uses a portion of low-temperature combustion gas discharged into a chimney to cool high-temperature combustion gas.

Claims (1)

[Claims] (1) A step of supplying solid fuel and compressed air to a combustion chamber, a step of combusting solid fuel in a fluidized bed with compressed air, and a step of discharging combustion gas from the fluidized bed into a chimney. A method of generating a process force to mix a portion of the low-temperature combustion gas in the fluidized bed) Adding low-temperature combustion gas to the combustion gas exiting from the fluidized bed to adjust the gas temperature to about 40°C to 600″C. The method according to claim 1 (3) The method according to claim 1, wherein the reheating temperature of the mixed gas is about 600"C to 950°C. (4) The gas turbine process is combined with a steam turbine process. The method (5) according to claim 1, in which the mixed gas exiting from the gas turbine is sent to a recuperator, and a part of the combustion gas exiting from the recuperator is added to the combustion gas exiting from the fluidized bed. , the remainder is discharged into a chimney (6) The method (6) according to claim 1, wherein the fluidized bed is cooled by heat exchange with water or steam immersed in the fluidized bed ( ?) having a solid fuel and air supply device, an air compressor connected to the air supply device, and a fluidized bed for solid combustion,
and a combustion chamber connected to the solid fuel supply device and the air compressor, and a combustion gas exhaust device provided in the combustion chamber;
A gas compressor for compressing a part of the combustion gas discharged into the chimney, a gas mixer that adds the gas to the combustion gas exiting the combustion chamber, and a dust removal device connected to the gas mixer. The device (9) as described in item 7 of the scope of interest takes out a part of the mixed gas discharged into the chimney,
The device according to claim 9, wherein the recuperator is connected to the chimney through a gas distribution pipe in order to discharge the combustion gases coming out of the fluidized bed and the remainder into the chimney.