JPS6310327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to automation of starting and stopping mills in coal-fired power plants.

The number of thermal power plants that use coal as fuel is increasing recently.

Automation of starting and stopping mills is important to reduce the burden on power plant operators.

In traditional coal-fired power plants, mills were started and stopped manually. It was inconvenient for power plant operators to frequently start and stop the mill while monitoring the generated power and heavy oil flow rate.

Figure 1 shows a general boiler turbine cooperative control system, or APC (AUTOPOWER PLANT).
FIG. 2 is a block diagram of heavy oil and coal co-firing control of the CONTROL control device.

In FIG. 1, 30 is a combustion amount command signal, 32
is a heavy oil flow rate, 31 is a mill coal feed amount, 46 to 49 are adders, 42 is a heavy oil proportional integral calculator, 15 is a heavy oil flow rate command control signal, 14 is a co-firing bias setter setting signal, 40 is a co-firing bias setter, 20 is a mill operation signal, 45 is a co-firing setting device, 39 is a co-firing setting value, 34 is a co-firing bias signal, 35 is a co-firing rate signal, 41 is a multiplier, 36 is a co-firing heavy oil flow rate, 43 is a mill coal feed proportional integral 16 is a mill coal feeding amount command control signal, and 44 is a mill cutting device.

Now, the heavy oil flow rate command control signal 15 is controlled via the heavy oil proportional integral calculator 42 based on the deviation between the combustion amount command signal 30 and the actual heavy oil flow rate 32 and mill coal feed amount 31. The co-firing rate signal 35 is the sum of the co-firing bias signal 34 and the co-firing set value 39. The co-firing bias signal 34 can be arbitrarily adjusted by the co-firing bias setter setting signal 14, and the co-firing set value 39
is determined by the mill operation (number of units) signal 20.

The larger the number of mills in operation, the smaller the co-firing setting value 39 becomes. In other words, co-firing setting value 39 = f (number of mills in operation), where f represents a function.

The co-firing rate is defined here as follows: Co-firing rate = Heavy oil flow rate (15) / Mill coal feed amount (31) + Heavy oil flow rate (15).

The co-firing heavy oil flow rate 36 is calculated by the product of the co-firing rate signal 35 and the combustion amount command signal 30.

Mixed combustion heavy oil flow rate 36 = Mixed combustion rate signal 35 x combustion amount command signal 30 The mill coal feed amount command control signal 16 is a combination of the combustion amount command signal 30 (+), the mixed combustion heavy oil flow rate 36 (-), and the actual mill coal feed amount 31 (-). ) is controlled by the deviation from

The mill coal feed amount during each operation is controlled by the mill coal feed amount command control signal 16, but when the control signal 16 approaches the upper limit, the mill in operation becomes overloaded.
Conversely, when the control signal 16 approaches the lower limit, the load on the mill in operation becomes small. By starting or stopping this mill, the mill coal feed amount command control signal 1
6 changes to the lower limit or upper limit side.

Therefore, for example, if a power plant operator wants to reduce the heavy oil flow rate (command control signal) 15 and start the mill (cutting device) 44 at a constant load,
First, an operator manually decreases the mixed combustion bias signal 34 using the mixed combustion bias setter 40 to reduce the heavy oil flow rate. At that time, the operator must constantly monitor the mill coal feed amount control signal 16, and manually start the mill when the control signal 16 approaches the upper limit. Control signal 16 is reduced.

As mentioned above, when increasing or decreasing the load, changing the heavy oil and coal co-firing ratio, or starting or stopping this plant, the operator always manually adjusts the co-firing bias setter 40 and manually starts the mill 44. It was necessary to stop the vehicle, which was a burden on the operators.

The present invention automatically starts and stops the mill while monitoring the generated power, mill coal feeding command, and mill operating status based on the target heavy oil flow rate and target generated power set by the operator. The purpose is to provide a mill control device that reduces the burden on the operator.

FIG. 2 is a block diagram schematically showing automatic mill start/stop control in one embodiment of the present invention.

In FIG. 2, a data setting device 21, a target mill operation number calculator 22, and a mill start/stop control device 25 are constituent elements of the present invention. Data setting device 2
1 outputs a target heavy oil flow rate signal 11 and a target generated power signal 12 to a target mill operation number calculator 22. The target number of mills in operation signal 13 is sent from the target number of mills in operation calculator 22 to the mill start/stop control device 25.
Output.

The mill start/stop control device 25 outputs a co-firing bias setter setting signal 14 and a mill start/stop command signal 18 to the APC control device 23 and the mill start/stop control sequence controller 24, respectively. The mill coal feed amount command control signal 16 is input from the APC control device 23 to the mill start/stop control device 25.

A heavy oil flow rate command control signal 15, a mill coal feed amount command control signal 16, and a mill start/stop control signal 17 from the mill start/stop controller 24 are each input to the plant 50 from the APC control device 23.

The generated power signal 19 and the mill operation signal 20 are sent to the mill start/stop control device 25 from the plant 50 side.
is input to.

Here, the details of the target mill operation number calculator 22 and the mill start/stop control device 25 are shown in the target mill operation number calculation flowchart in FIG. 3 and the mill start/stop control flowchart in FIG. 4, respectively. There is.

Now, the operation of the present invention will be described.

In FIG. 2, when a power plant operator sets a target heavy oil flow rate and a target generated power using a data setter 21, a target heavy oil flow rate signal 11 and a target generated power signal 12 are sent to a target mill operating number calculator 22.

The target number of mills in operation calculation unit 22 calculates the target number of mills in operation based on the target heavy oil flow rate signal 11 and the target generated power signal 12 in accordance with the target number of mills in operation flowchart shown in FIG.

If N is the target number of mills in operation, according to Figure 3, N = FRD - FFD / F _RATE ... (1 equation) where FFD is the target heavy oil flow rate 12 from the data setting device 21, and F _RATE is the number of mills per mill 44. Predetermined coal feeding capacity (constant), FRD=f(MWD) (2 formulas), where MWD is the target generated power 12 from the data setter 21. Therefore, FRD is the target combustion amount command 30.

The target mill operation number signal 13 calculated by the target mill operation number calculation unit 22 as described above is sent to the mill start/stop control device 25.

The mill start/stop control device 25 is based on the target mill operation number signal 13, the mill coal feed amount command control signal 16 from the APC control device 23, the generated power signal 19 from the plant 50 side, and the mill operation signal 20. Then, according to the mill start/stop control flowchart in Figure 4, start/stop the mill 44 until the target number of units is in operation.
make it stop.

In FIG. 4, the mill start/stop control device 25
To explain this, the mill coal feed amount command control signal 16 is input from the APC control device 23.

() A case where the mill coal feed amount command control signal 16 approaches the upper limit will be described.

When the mill coal feed amount command control signal 16 approaches the upper limit value and the number of mills 44 in operation is less than the target number of mills in operation, the mill start/stop command signal 1
8 is output to the mill start/stop control sequence controller 24 to start the mill 44.

When the mill coal feed amount command control signal 16 approaches the upper limit value and the number of mills 44 in operation is equal to or greater than the target number of mills in operation, the co-firing bias setter setting signal (increase) 14 is sent to the APC control device 23. The co-fired heavy oil flow rate 36 is increased and the mill coal feed amount command control signal 16 is decreased.

() A case where the mill coal feed amount command control signal 16 approaches the lower limit will be explained.

The process when the mill coal feed amount command control signal 16 approaches the lower limit value is the opposite of the above ().

If the mill coal feed amount command control signal 16 approaches the lower limit value and the number of mills 44 in operation is greater than the target number of mills in operation, the mill start/stop command signal 18
A stop signal is output to the mill start/stop control sequence controller 24 to stop the mill 44.

When the mill coal feed amount command control signal 16 approaches the lower limit value and the number of mills 44 in operation is equal to or less than the target number of mills in operation, the co-firing bias setter setting signal (decrease) 14 is sent to the APC control device 23. output, reduce the co-fired heavy oil flow rate 36,
The mill coal feed amount command control signal 16 is increased.

() A case will be described in which the mill coal feed amount command control signal 16 is within a certain intermediate range.

When the number of mills 44 in operation is less than the target number of mills in operation, the co-firing bias setter signal (reduction) 14 is output to the APC control device 23, the co-firing heavy oil flow rate 36 is reduced, and the mill coal feeding amount command control signal is output. 16, and when the mill coal feed amount command control signal 16 approaches the upper limit, a mill start/stop command signal (start) 18 is output to the mill start/stop control sequence controller 24, and the mill 44 is started.

When the number of mills 44 in operation is greater than the target number of mills in operation, the co-firing bias setter signal (increase) 14 is output to the APC control device 23, the co-firing heavy oil flow rate 36 is increased, and the mill coal feeding amount command control signal is output. 16, and when the mill coal feed amount command control signal 16 approaches the lower limit, a mill start/stop command signal (stop) 18 is output to the mill start/stop control sequence controller 24, and the mill 44 is stopped.

Thus, according to the present invention, as described above, it is possible to automatically start and stop the mill as much as the target heavy oil flow rate and target generated power are given by the power plant operator, reducing the burden on the operator and improving the efficiency of the mill. It is operated efficiently and has effects such as energy saving.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of heavy oil and coal mixed combustion control of APC in a coal-fired power plant, Fig. 2 is a block diagram showing the configuration of an embodiment of the present invention, Fig. 3 is a flowchart for calculating the target number of mills in operation, Figure 4 is a flowchart of the mill start/stop control. 11...Target heavy oil flow rate signal, 12...Target generated power signal, 13...Target mill operating number signal, 14
...Mixed firing bias setter setting signal, 15...Heavy oil flow rate command control signal, 16...Mill coal feeding amount command control signal, 17...Mill start/stop control signal, 18
... Mill start/stop command signal, 19 ... Generated power signal, 20 ... Mill operation signal, 21 ... Data setting device, 22 ... Target mill operation number calculator, 23
...Boiler turbine cooperative control device (APC control device), 24... Mill start/stop control sequence controller, 25... Mill start/stop control device, 30... Combustion amount command signal, 31... Mill coal feed amount, 32...Heavy oil flow rate, 34...Co-firing bias signal, 35...Co-firing rate signal, 36...Co-firing heavy oil flow rate, 39...Co-firing setting value, 40...Co-firing bias setter, 41...Multiplier, 42... ...Heavy oil proportional integral calculator, 43...Mill coal feeding amount proportional integral calculator,
44... Mill cutting device, 45... Co-firing setting device, 4
6-49...Adder, 50...Plant.

Claims (1)

[Claims] 1. A boiler turbine cooperative control device that outputs a heavy oil flow rate command control signal and a mill coal feed amount command control signal from a heavy oil and coal co-firing control circuit to the plant, and a mill start/stop control sequence that outputs a mill start/stop control signal to the plant. In a coal-fired power plant equipped with a controller, there is a data setting device that sets a target heavy oil flow rate and target generated power, and a target heavy oil flow rate signal and a target generated power signal are input from this data setting device, and the target is set based on these two signals. A target mill operation number calculator for calculating the number of mills in operation; a target mill operation number signal is inputted from the target mill operation number calculator; a mill coal feed amount command control signal is inputted from the boiler turbine coordination control device; A generated power signal and a mill operation signal are input, and based on these four signals, a co-firing bias setter setting signal is output to the boiler turbine coordination control device, and a mill start/stop command signal is sent to the mill start/stop control sequence controller. It consists of a mill start/stop control device that outputs output, and automatically starts/stops the mill up to the target number of operating units according to the set target heavy oil flow rate and target generated power.
A mill control device characterized by stopping.