JPH09287882A - Control device of high pressure steam condenser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a controllability thereby enhancing maintenance and safety in operation of a high pressure steam condenser. SOLUTION: A control device of a high pressure steam condenser executes a feed- forward control, wherein in carrying out a constant condensing temperature control and a constant inner pressure control, an inflow vapor amount which is a main disturbance is detected and a compensation amount computed from the detected inflow vapor amount is added to both control outputs. In such a feed-forward control, a saturated water and saturated vapor weight computing device 15 is provided for estimating a vapor-condensation ratio using other physical quantity. As such a physical quantity, a weight of the condenser 1 is used. To calculate the weight of the condenser 1, the condenser 1 is mounted on a support portion. The vapor-condensation ratio ranging from 0 to 100% is divided in N and control models of N patterns are prepared. A plurality of controllers are designed corresponding to these control models of N patterns and these controllers constitute a condensing temperature control device 10 (so as the inner pressure control device 11). Due to such a control, the condensing temperature control device and the inner pressure control device can have control characteristics which correspond to the vapor-condensation ratio so that the controlling operation can follow the nonlinear characteristics of the condenser.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a high-pressure steam condenser that controls the condensate temperature and internal pressure of the high-pressure steam condenser in a refuse incineration power generation facility and the like to be constant.

[0002]

2. Description of the Related Art The configuration of a conventional example is shown in FIG. In the figure, 1 is a high pressure steam condenser, 2 is a high pressure steam reservoir, 3 is a high pressure steam reservoir pressure control valve, 4 is a high pressure steam condenser pressure control valve, 5 is high pressure steam reservoir 2 to high pressure steam reservoir pressure control. A flow meter for measuring the flow rate of superheated steam flowing into the high-pressure steam condenser 1 through the valve 3, 6
Is a pressure gauge for measuring the pressure of superheated steam flowing into the high-pressure steam condenser 1, 7 is a thermometer for measuring the condensate temperature, 8 is a cooling fan for cooling the high-pressure steam condenser 1 with air, and 9 is A VVVF (variable voltage variable frequency) inverter device for controlling the rotation speed of the cooling fan 8, 10 'is a condensate temperature control device, 11' is an internal pressure control device, and 12 is a compensation amount based on a steam flow rate detection value. A feed-forward compensation amount calculation unit that calculates and performs output compensation of the condensate temperature control signal, and a feed-forward compensation amount calculation unit that calculates the compensation amount based on the steam flow rate detection value and performs output compensation of the internal pressure control signal. It is a quantity calculation unit.

In the above structure, the condensate temperature constant control and the in-container pressure constant control are performed. In both controls, feed-forward control is performed in which the amount of inflow steam, which is the main disturbance, is detected and the compensation amount calculated from the detected amount is added to the condensate temperature control output and the internal pressure control output. It is being appreciated.

[0004]

Since a phase change from steam to water occurs in the high-pressure steam condenser in the high pressure steam condenser 1, cooling for the purpose of constant condensate temperature control accelerates the phase change of the steam and the inside of the condenser is cooled. Induces pressure fluctuations. Further, opening / closing of the high-pressure steam condenser pressure control valve 4 for the purpose of constant pressure control in the vessel induces fluctuation of the (steam / condensate) ratio in the condenser 1. (Steam / condensate)
When the ratio is large, the pressure fluctuation due to the phase change due to cooling is steep, and conversely, when the (steam / condensate) ratio is small, it becomes slow. This is because the time constant indicating the physical characteristics of the high-pressure steam condenser 1 includes the parameter of the total heat capacity of the condenser 1, and thus has a non-linearity mainly due to the change of the heat capacity. The non-linearity of the physical characteristics of the condenser 1 makes the controller designed by linearization unstable in a certain steady state, and significantly deteriorates the controllability.

Overcooling or insufficient cooling of condensate water due to unstable control of the high-pressure steam condenser 1 causes damage to the high-pressure steam condenser 1. The supercooling increases the thermal stress strain due to the temperature difference between the inlet side and the outlet side of the condenser 1. The outflow of steam due to insufficient cooling causes damage to the expansion joint used in the joint portion of the pipe for the purpose of absorbing the thermal stress strain of the condenser 1. Further, the instability of the internal pressure control becomes a disturbance of the pressure control of the high pressure steam reservoir 2 located on the primary side of the condenser 1, and affects the controllability of the high pressure steam reservoir 2.

The main problems are listed below.

(1) Fluctuations in cooling efficiency due to opening / closing of the high-pressure steam condenser pressure control valve 4 (2) Controller designed assuming a steady state of (steam / condensate) ratio (3) Condensate temperature Interference between constant control and constant internal pressure control Parameters that determine the heat capacity are temperature, pressure, and (steam / condensate) ratio. Considering that the purpose of control is the internal pressure and the condensate temperature, and considering that these can maintain steady values, the nonlinearity of the condenser can be calculated by knowing the (steam / condensate) ratio. It can be reflected in the controller considering the nonlinearity of the characteristics. However, it is difficult to measure the (steam / condensate) ratio directly as a physical quantity with a measuring instrument, and it is estimated from other physical quantities by some indirect method.

The present invention has been made in view of the above circumstances. By indirectly measuring the (steam / condensate) ratio and varying the control parameter, the controllability can be improved, and in turn the equipment maintenance and safety can be improved. It is an object of the present invention to provide a control device for a high-pressure steam condenser that can be expected to improve its performance.

[0009]

According to the present invention, when the condensate temperature constant control and the in-vessel pressure constant control are performed, the amount of inflowing steam, which is the main disturbance, is detected, and the compensation amount calculated from the detected amount is controlled in both cases. In a controller for a high-pressure steam condenser that performs feed-forward control to add to the output, a saturated water / saturated steam weight calculator that estimates the (steam / condensate) ratio by calculation using other physical quantities is provided. , (Steam / condensate) ratio control value corresponding to the estimated value is provided in the condensate temperature control device and the internal pressure control device.

Further, in the present invention, the weight of the condenser body is used as another physical quantity for estimating the (steam / condensate) ratio, and the estimated value of the (steam / condensate) ratio is calculated by The feature is that it is calculated from the estimated water flow rate and the estimated amount of condensation.

[0011]

1 to 3 show one embodiment of the present invention. 1 is an overall configuration diagram, FIG. 2 is a layout diagram of a (steam / condensate) ratio estimating means, and FIG. 3 is a schematic explanatory diagram of a main part. In this embodiment, the weight of the condenser is used as an indirect physical quantity for estimating the (steam / condensate) ratio. In the figure, 1 is a high pressure steam condenser, 2 is a high pressure steam reservoir, 3 is a high pressure steam reservoir pressure control valve, 4 is a high pressure steam condenser pressure control valve, 5 is high pressure steam reservoir 2 to high pressure steam reservoir pressure control. A flow meter for measuring the flow rate of the superheated steam flowing into the high pressure steam condenser 1 through the valve 3, 6 is a pressure gauge for measuring the pressure of the superheated steam flowing into the high pressure steam condenser 1, and 7 is a condensate temperature. A cooling fan for cooling the high-pressure steam condenser 1 by ventilation, 9 a VVVF (variable voltage variable frequency) inverter device for controlling the rotation speed of the cooling fan 8, and 10 a condensate temperature control A device, 11 is an internal pressure control device, 12 is a feed-forward compensation amount calculation unit that calculates a compensation amount based on the steam flow rate detection value, and performs output compensation of the condensate temperature control signal, and 13 is a steam flow rate detection value. Compensation amount is calculated based on the A feed / forward compensation amount calculation unit for compensation, 14 is a weight measuring device installed on the supporting portion of the condenser 1, and 15 is an output of the weight measuring device 14, that is, the weight of saturated water / saturated steam from the weight measurement value. Saturated water / saturation for instructing the condensate temperature control device 10 and the in-container pressure control device 11 to change (select) the control characteristics according to the estimated value of the (steam / condensate) ratio (control parameter) It is a vapor weight calculation device. As shown in FIG. 2, the condenser 1 is provided with a weight measuring device 14 on its support portion, while the superheated steam inflow portion and the condensate outflow portion are provided with movable portions 1a and 1b made of flexible pipes or the like. . The condensate temperature control device 10 and the internal pressure control device 11 can change (select) their control characteristics according to the (steam / condensate) ratio of control parameters.

The condenser 1 measured by the weight measuring device 14
The total weight of is the sum of: However, here, the steam weight inside the condenser 1 is approximately calculated by assuming that the steam and the condensate are in a saturated state. As the saturation temperature T, the measured value of the condensate temperature T _out of the outlet and the average value of the steam temperature T _in of the condenser inlet side (T = (T _in + T _out ) / 2 [° C.]) are used.

V = (v _V * x + (1-x) v _L ) (W _V + W _L ) x = {(W _V + W _L ) V + v _L } / (v _V −v _L ) = W _V / (W _V + W _L ) W _V = (W _V + W _L ) {(W _V + W _L ) V + v _L } / (v _V −
v _L ) where V: total volume [m ³ ], v _V (T): specific volume of saturated steam [m ³ / kg], v _L (T): specific volume of saturated water [m ³ / k]
g], x: dryness, W _V : saturated steam weight [kg], W _L :
Saturated water weight [kg].

Sum of saturated steam weight and saturated water weight (W _V +
W _L ) is a value obtained by subtracting the weight W _C [kg] of the condenser main body from the weight measurement value W [kg], that is, W _V + W _L = W−W _C. Therefore, the estimated value of the saturated steam weight is as follows.

W _V = (W-W _C ) {(W-W _C ) V + v _L }
/ ( _{V V} −v _L ) When the characteristics of the controller are successively modified (selected) using the above values, the nonlinearity of the condenser, which causes deterioration of controllability, is reflected in the characteristics of the controller. And the controllability is improved.
A configuration example of the condensate temperature control device 10 is shown in FIG.

The condensate temperature control device 10 is (steam / condensate)
A linear condensate temperature controller C-1 to C-N designed by dividing the ratio 0 to 100% into N and designed for an N pattern control model.
And the switching units K1 and K2 are used for switching. The switching control of the switching units K1 and K2 is performed by calculating the weight of the saturated water / saturated steam from the weight measurement value and further calculating the estimated value of the (steam / condensate) ratio. I am going to do it. The saturated water / saturated steam weight calculation device 15 includes a saturated water / saturated steam weight calculation unit 15
A and (steam / condensate) ratio calculation unit 15B.

The internal pressure control device 11 has the same structure as the condensate temperature control device 10.

With such a configuration, (steam / condensate)
The control characteristic takes into account the nonlinearity of the controlled object due to the influence of the ratio, and the controllability is significantly improved. Improvement of controllability improves equipment maintenance and safety, reduces disturbance to the high pressure steam reservoir 2 located upstream, and stabilizes steam supply to steam utilization equipment.

FIG. 4 shows another embodiment of the present invention. FIG.
Is an overall configuration diagram. In this embodiment, the estimated value of the (steam / condensate) ratio is the condensation amount estimated from the fan rotation speed,
It is calculated from the measured steam flow rate and condensate flow rate.
In the figure, 1 is a high pressure steam condenser, 2 is a high pressure steam reservoir, 3 is a high pressure steam reservoir pressure control valve, 4 is a high pressure steam condenser pressure control valve, 5
Is a flow meter for measuring the flow rate of superheated steam flowing from the high-pressure steam reservoir 2 through the high-pressure steam reservoir pressure control valve 3 into the high-pressure steam condenser 1, and 6 is a flowmeter of the superheated steam flowing into the high-pressure steam condenser 1. A pressure gauge for measuring the pressure, 7 a thermometer for measuring the condensate temperature, 8 a cooling fan for cooling the high-pressure steam condenser 1 by ventilation, and 9 a VVV for controlling the rotation speed of the cooling fan 8.
F (variable voltage variable frequency) inverter device, 10 is a condensate temperature control device, 11 is an internal pressure control device, 12 is a compensation amount calculated based on the steam flow rate detection value, and the output of the condensate temperature control signal is compensated. Feed forward compensation amount calculation unit
13 is a feed / forward compensation amount calculation unit that calculates a compensation amount based on the steam flow rate detection value and performs output compensation of the internal pressure control signal, and 15 calculates the weight of saturated water / saturated steam,
A saturated water / saturated steam weight calculation device for instructing the condensate temperature control device 10 and the internal pressure control device 11 to change (select) the control characteristic according to the estimated value of the (steam / condensate) ratio, and 16 is the above A flow meter installed at the outlet side of the high-pressure steam condenser 1 for measuring the condensate flow rate, and 17 is a rotation speed command of the VVVF inverter device 9, that is, a condensation amount estimated value is calculated from the rotation speed of the cooling fan 8. This is a condensation amount estimated value calculation unit. In the saturated water / saturated steam weight calculation device 15, the steam flow rate measurement value from the flow meter 5, the condensate flow rate measurement value from the flow meter 16, and the condensation amount estimation value from the condensation amount estimation value calculation unit 17 are received. They are given respectively, and due to the conservation of mass (steam /
Calculate the estimated value of the condensate) ratio. The condensate temperature control device 10 and the in-container pressure control device 11 have the same configurations as in the above-described embodiment.

The estimated value of the condensed amount G is expressed as a function of the air flow rate W _F proportional to the fan rotation speed. That is, G = f (W _F). Here, G: condensation amount [kg / s], W _F : air flow rate [kg / s].

With such a configuration, (steam / condensate)
The control characteristic takes into account the nonlinearity of the controlled object due to the influence of the ratio, and the controllability is significantly improved. Moreover, it is easy to take in the fan rotation speed and the steam flow rate measurement value for estimating the condensation amount, and it is only necessary to install the flow meter 16 for measuring the condensate flow rate on the outlet side of the high-pressure steam condenser 1. It can be applied to existing equipment relatively easily. Further, even if the weight of the condenser body changes due to secular change such as oxidation, the accuracy is maintained without being affected by the change.

In the above description, the (steam / condensate) ratio of 0 to 100% is divided into N parts, and is composed of a plurality of controllers designed for an N pattern control model.
It is also possible to use the estimated value of the (steam / condensate) ratio as a parameter and change it to a corresponding control characteristic.

[0023]

As described above, according to the present invention, the (steam / condensate) ratio inside the high-pressure steam condenser is estimated from other physical quantities by calculation, and the (steam / condensate) ratio of the controller is calculated. Since the control characteristics are reflected, it is possible to perform control that follows the non-linearity of the condenser, and it is possible to significantly improve the controllability. Further, with the improvement of controllability, it is possible to improve equipment maintenance and safety, and contribute to reduction of disturbance to the high-pressure steam reservoir located upstream and stable steam supply to steam utilization equipment, There are advantages such as.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a layout view of a physical quantity measuring unit for estimating a (steam / condensate) ratio in one embodiment.

FIG. 3 is a structural explanatory view of a condensate temperature control device according to an embodiment.

FIG. 4 is an overall configuration diagram showing another embodiment of the present invention.

FIG. 5 is an overall configuration diagram showing a conventional example.

[Explanation of symbols]

 1 ... High-pressure steam condenser 2 ... High-pressure steam reservoir 3 ... High-pressure steam reservoir pressure control valve 4 ... High-pressure steam condenser pressure control valve 5 ... Flowmeter (steam flow rate) 6 ... Pressure gauge 7 ... Thermometer 8 ... Cooling fan 9 ... VVVF inverter device 10 ... condensate temperature control device 11 ... internal pressure control device 14 ... weight measuring device 15 ... saturated water / saturated steam weight calculation device 16 ... flowmeter (condensate flow rate) 17 ... condensation amount estimated value calculation Department

Claims (3)

[Claims] 1. A feed forward, which detects the amount of inflowing steam, which is a main disturbance, and adds the compensation amount calculated from the detected amount to both control outputs when performing the condensate temperature constant control and the internal pressure constant control. In the controller of the high-pressure steam condenser that performs control, a saturated water / saturated steam weight calculator that estimates the (steam / condensate) ratio by calculation using other physical quantities is installed, while the (steam / condensate) ratio A control device for a high-pressure steam condenser, wherein the condensate temperature control device and the internal pressure control device are provided with control characteristics corresponding to the estimated value of. 2. The control device for the high-pressure steam condenser according to claim 1, wherein the weight of the condenser main body is used as another physical quantity for estimating the (steam / condensate) ratio. 3. The high-pressure steam condensate according to claim 1, wherein an estimated value of the (steam / condensate) ratio is obtained by calculation from a steam flow rate, a condensate flow rate, and an estimated value of the amount of condensation. Control device.