JPS6238601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for starting a fluidized bed boiler.

Due to the recent oil situation, coal-burning boilers, especially fluidized bed boilers, are attracting attention from the viewpoint of low NOx and dust emissions. On the other hand, however, a characteristic of a fluidized bed furnace is that the fluidized medium must be heated upon startup, which poses problems that must be resolved, such as the cost of auxiliary fuel, NOx removal from exhaust gas during startup, and dust collection. On the other hand, when granular coal is incinerated, a considerable amount of collected ash (hereinafter referred to as EP ash) containing unburned components (unburnt carbon) is emitted due to low O ₂ combustion to maintain low NOx. There are also issues to deal with. For this reason, a separate furnace is provided to incinerate the collected ash, and in particular, incineration using a furnace using a fluidized bed is adopted as a preferable means. This invention aims to simultaneously solve the problem of efficient startup of equipment and the removal of NOx and dust at that time.

The purpose of this invention is to propose a means for effectively using an EP ash incinerator when starting up a fluidized bed boiler.

In short, this invention is a method for starting a fluidized bed boiler having a collected ash incinerator, in which the collected ash incinerator is started by burning fossil fuel and the exhaust gas is supplied to the fluidized bed boiler to start the fluidized bed boiler. A method.

An embodiment of the apparatus according to the present invention will be described below with reference to FIG. The exhaust gas of the fluidized bed boiler 1 (the fluidized bed boiler described in this specification is a name representative of the main incinerator, and a boiler using a fluidized bed will be explained as an example) is passed through the evaporator 2b,
2c, a carbon economizer 3, a cyclone dust collector 4, an electrostatic precipitator (EP) 5, a catalytic denitrification device 6, and an induction fan 7 before being released into the atmosphere from a chimney 8. An evaporator 2a and a superheater 10 are provided in the fluidized bed 9, and the vapor from the evaporator is sent to the drum 1a and to the drum 1.
Steam from a is sent via a superheater 10 and a conduit 11 to a steam device (not shown) such as a turbine.

Fig. 1 shows a case where powdered fine granule coal is used as fuel, and the powdered limestone from the limestone hopper 12 and the powdered fine granulated coal from the powdered fine coal hopper 13 are passed through double rotary feeders 12a and 13a, respectively. The compressed air from the blower 14 is airflow-transported through the pipe 15 via the damper 14a, and is supplied into the fluidized bed 9 by the burner 16, where it is combusted in the bed. Combustion air is supplied to the air chamber 18 of the fluidized bed boiler via a pipe line 17 and a damper 19 that branch at the outlet of the blower 14.

On the other hand, the collected ash collected by the electrostatic precipitator (EP) 5 is incinerated in a collected ash incinerator 20 (in this case, a fluidized bed furnace is used, so within the fluidized bed 20a). The collected ash incinerator 20 is started by burning fossil fuel (oil, gas, and pulverized coal collectively) using a bed auxiliary combustion burner 21 and the like. Since the fluidized bed furnace 20 usually has a small capacity, the amount of NOx dust generated during startup is small and does not pose a problem.
By discharging to the main exhaust gas pipe 32 via the damper 25a, the gas passes through the EP 5 and the catalytic denitrification device 6, thereby making it possible to further ensure NOx removal and dust collection. The connection point between the pipe 25 and the main exhaust gas pipe is connected to the cyclone dust collector 4 to balance the discharge pressure.
It is preferable to use the main exhaust gas pipe line 32 between the main exhaust gas pipe and the EP5. Fossil fuel air is supplied to the air chamber 23 via a pipe 17a branching from the pipe 17 and a damper 22. After the temperature of the fluidized bed 20a of the collected ash incinerator 20 has risen sufficiently, the pipe 2 branching from the blower 14
6. The collected ash of the cyclone dust collector 4 and the collected ash of the EP 5 are supplied into the pipe line 26 via the rotary feeders 4a and 5a, respectively, by the pressurized air passing through the damper 26a, and the collected ash is transferred to the pipe line by air flow transport. The burner 28 is supplied via a conduit 27 connected to the burner 26 . This collected ash is supplied to the fluidized bed 20a from the burner 28 and is incinerated within the bed.

In this invention, in order to start the fluidized bed boiler 1, the exhaust gas from the collected ash incinerator 20 is transferred to the fluidized bed via a booster fan 30 and a damper 31 through a pipe 29 branching from the pipe 25 without being disposed of via the pipe 25. It is supplied to the air chamber of the boiler 1 and heats the fluidized medium forming the fluidized bed 9 using the amount of heat it possesses.

In this case, only the pulverized granulated coal to be supplied to the fluidized bed boiler as fossil fuel is fed from the pulverized granulated coal hopper 13 to the blower 1 by the double rotary feeder 13b.
A damper 26
It is also possible to start the collected ash incinerator 20 by transporting the compressed air through the pipes 26 and 27 and supplying it to the fluidized bed 20a by the burner 28. In addition, the pipe line 15, the damper 15b, the pipe line 15a, the pipe line 27,
A mixture of limestone powder and fine granulated coal can also be supplied to the fluidized bed 20a via the burner 28.

In this way, the pipe line 29, booster fan 30, double rotary feeder 13b, pipe line 26, damper 26a
By simply adding , the fluidized bed boiler 1 serving as the main incinerator can be started using the heat retained in the exhaust gas of the collected ash incinerator.

By carrying out this invention, dust in the exhaust gas from the fluidized bed boiler during startup can be sufficiently removed, NOx can be removed, the amount of heat retained in the exhaust gas from the collected ash incinerator can be effectively utilized, and the It saves costs, and has various effects such as being able to modify existing equipment with a small addition of equipment piping.

[Brief explanation of the drawing]

FIG. 1 is a drawing showing the arrangement of equipment and piping system according to the present invention. 1... Fluidized bed boiler, 13b... Double rotary feeder, 20... Collected ash incinerator, 25, 26,
27, 29...pipe line, 32...main exhaust gas pipe line.

Claims (1)

[Claims] 1. A method for starting a fluidized bed boiler having a collected ash incinerator, which includes starting the collected ash incinerator by burning fossil fuel and supplying the exhaust gas to the fluidized bed boiler. Features: How to start a fluidized bed boiler. 2 A pipe line that supplies the collected ash to the collected ash incinerator is used to supply only pulverized coal into the bed, the collected ash incinerator is started, and the flue gas is used to start the fluidized bed boiler. A method for starting a fluidized bed boiler according to claim 1. 3. A patent claim characterized in that the fluidized bed boiler is started while exhaust gas is sucked from the downstream of a dust collector for collected ash incinerator exhaust gas, the pressure is increased by a booster fan, and the fluidized bed boiler is supplied to the air chamber of the fluidized bed boiler. A method for starting a fluidized bed boiler according to scope 1 or 2.