JPS5989924A - Inlet air pressure control device of fluidized bed boiler - Google Patents

Abstract

PURPOSE:To contrive the reducing of an electric power and the improvement of controllability of an inlet damper by a method wherein a driving motor of a forced blower is controlled at desired number of revolutions, and an air pressure at the inlet of a boiler is varied according to a operational condition of the boiler. CONSTITUTION:Signals outputted from a boiler inlet air pressure setting devices 13, 14 due to a master command 12 are selected with a changeover controller 15 according to the operation, that is, single shell operation or both shell operation, further, a signal is inputted into a velocity controller 11 via a pressure controller 16, then the rotational speed of a driving motor 4 is controlled. The signals outputted by the master command 12 from boiler inlet air flow rate setting devices 18, 19 correspond to each shell 1, 2 are introduced into open/close driving devices 22, 23 via air flow rate controllers 20, 21, then inlet dampers 9, 10 are opened or closed. Thereby, the reducing of an electric power and the improvement of controllability of an inlet dampers can be contrived.

Description

[Detailed description of the invention] Regarding equipment.

Figure 1 shows an example of a fluidized bed boiler equipped with two cells (α) and (b), in which air from a forced air blower (c) is
Main air pipe (e) with gas air heater (d) in the middle
i and branch pipes (1) (g) to each cell (α) (b) of the fluidized bed boiler, and the exhaust gas discharged from the fluidized bed boiler is supplied through the exhaust gas pipe (fh). The supplied air is guided to the gas air heater (d) to preheat the supplied air.

Conventional air pressure control in such a fluidized bed boiler involves operating the drive motor (i) of the forced air blower (cl) at a constant speed, and installing a main tamper (jl and pressure) downstream of the forced air blower (c). A detector (kl is provided and the cell (α
) (b) via the pressure regulator (1) based on the detected value from the pressure detector (&) so that the overall air pressure supplied to the air pressure sensor (&) is always kept constant. The opening degree of the main tamper (jl) is adjusted by adjusting the opening of the main tamper (jl), and an artificial damper (7+11 (nl) is provided for each of the branch pipes (f) and (g), and the artificial damper (jl) is ?L) is separately opened and adjusted by a mask command (o).

However, in the conventional method described in Section 2, the main tamper (j) and the artificial damper (ml (tt)) are controlled separately, and the air that passes through the main tamper (f) is always at a constant high pressure (high load state). population damper (-1
713 (n) and try to operate at low load,
Or, if one side of the artificial damper (-)f==) is shut off and a cell operation method such as single-cell operation is adopted, ``=;
): Main tamper (j
) is throttled, so that the drive motor (
This results in problems such as an unnecessarily large load being placed on the plant, making low-load operation impossible, and causing an increase in internal power. In addition, especially during low load operation, each cell (a
When adjusting the inlet pressure of ,)(b), the pressure changes significantly with a slight change in the artificial damper &,) (,), so fine adjustment is difficult and controllability is poor. I had a problem.

The present invention was made in order to solve the problems of the conventional method.The rotation speed of the drive motor of the forced blower is controlled by a mask command, and the air pressure at the inlet of the boiler is adjusted according to the operating conditions of the boiler. By varying this, it is possible to reduce the internal power and improve the opening property of the inlet damper.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an example of the present invention applied to the fluidized bed boiler shown in FIG. ) is the forced air blower, (4) is the drive motor, (5) is the main air pipe,
(6) is a gas air heater, (7) and (8) are branch pipes,
(9) αq indicates an inlet damper In the above configuration, the drive motor (4) is provided with a speed control device (11), and a boiler artificial air pressure setting device (13) for single-cell operation that is output by the mask command and (S→
- the same is switched and selected via the switching controller Q, and the selected signal is sent to the speed side 1fll via the pressure regulator αG.
l device (main air pipe (5) VC to detect whether the internal pressure of the main air pipe (5) is at a predetermined value.
A pressure detector (17) is provided, and a detection signal of the α force of the pressure detector is input to the pressure regulator 00 to control the rotational speed of the drive motor (4) so that the boiler inlet pressure is at the target value. 111, I"1"6 is created.

In addition, according to the mask command @, each cell (11 (boiler inlet air flow rate setting device a8 that separately sets and outputs the inlet air flow rate in 21) (signal from the seagull) is transmitted to the air #r, the amount regulator (a) Qυ and the urgent flow regulator is) CD
The opening/closing drive devices k (a) and (e) of each artificial damper (9) are controlled by the signal from each branch pipe (7) (81).
Flowmeters (to) (c) are installed in each branch pipe (7) and (8) to detect whether the air flow rate within the pipe is at a predetermined value. is input to the air flow rate regulator (e)@1)K to control the air flow rate supplied to each cell (11 (21) to a target value.

According to the above configuration, the signal from the boiler inlet air pressure setting device (+3 (14)) output by the mask command (2) is applied to the switching controller α according to the operating state of one cell operation or both cell operation. The signal is then input to the speed controller ([υ) via the pressure regulator 00 to drive the drive motor (
Since the rotational speed control described in 4) is performed, the boiler artificial air pressure can be controlled to a pressure that corresponds to the boiler load state and cell operating state based on the mask command α. Also, at this time, reliable pressure adjustment is performed by feedback control of the pressure detector 07).

Each cell (1) (2) output by mask command 0 effect
) The signal from the boiler inlet air flow rate setting device (to) 01 shift corresponding to the boiler inlet air flow rate setting device (to) is sent to the opening/closing drive device (a) via each air flow rate regulator (Q)), and the artificial damper (9) Q (It
to open and close. In the case of single-cell operation, one of the inlet dampers (91 (10) is closed, and the other is controlled to adjust the air flow rate according to the load of the mask command 0 by the feedback signal of the flowmeter (goods) or (c). Opening control is performed to ensure that A.Also, when negative and ij fluctuations occur during both cell operation, the boiler inlet air pressure changes accordingly, so the inlet damper (91QG) hardly moves. .Furthermore, the boiler inlet air pressure is
Since it is controlled in relation to the air flow rate of 1 person, the inlet damper (9) αO is largely rotated to control (al
There is no need to rotate the drive motor (4), and extremely high precision control can be achieved through its rotation, improving controllability.Moreover, there is no unnecessary load on the drive motor (4). Can be operated with low internal power.

Similarly, the present invention is not limited only to the above-described two embodiments, and various changes may be made without departing from the gist of the present invention.

Inlet air pressure control of the fluidized bed boiler of the present invention described above 1jl
According to this device, the following advantages can be obtained.

(1) Stable low-load operation is possible.

(ti) Since the boiler inlet air pressure is controlled according to the boiler load conditions, etc., there is no unnecessary load acting on the drive motor of the forced blower, and it can be operated with low internal power.

(iii) It is not necessary to make a large rotational adjustment of the human rodan bar, and control accuracy by rotation is improved, so that controllability can be improved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of a conventional method, and Fig. 2 is an explanatory diagram showing an embodiment of the present invention. Motor, (5)
is the main air pipe, (71 (&l) is the branch pipe, (9) QO+ is the person 1 damper, 0υ is the speed control device, a are the mask commands, (I61 is the pressure regulator, +201 C2υ is the air flow regulator) show.

Claims (1)

[Claims] 1) An inlet air pressure control device 0 for a fluidized bed boiler, characterized in that a speed control device is provided in the drive motor of the forced air blower, and a mask command is introduced into the speed control device via a pressure regulator.