JPS6043103A - Steam system controller - Google Patents

Abstract

PURPOSE:To converge the pressure fluctuation in a steam common mother pipe within a short time by performing an adjustment of an inlet steam valve opening degree and a boiler combustion control prior to a temperature and pressure reduction valve upon a load change. CONSTITUTION:When a load change occurs in steam load facilities 3, the pressure fluctuation in the steam common mother pipe 7 at the low pressure side is detected by a detector 11, and the opening degree adjustment of a turbine inlet steam valve 9 and control of a boiler fuel adjusting valve 8 are performed prior to the temperature and pressure reduction valve 10, based on the result of a calculation carried out by an operation controller 4. By this procedure, the pressure fluctuation in the low pressure side steam common mother pipe 7 can be converged in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention provides a method for controlling the amount of evaporation of a boiler in response to sudden changes in steam load.
The present invention relates to a steam system control device that adjusts a turbine inlet steam flow rate, etc.

[Technical background of the invention and its problems]

Conventionally, when maintaining the pressure of the steam common main pipe constant in response to load fluctuations in the steam system, the steam common main pipe pressure was detected, and the turbine inlet steam valve was first adjusted based on the pressure change to adjust the turbine inlet steam flow rate. .

Next, boiler combustion control is performed based on the resulting change in turbine inlet steam pressure, and the boiler evaporation amount is adjusted to sequentially stabilize the steam system. There was a problem in that it took a long time to reach control and the response was not good enough to absorb steam load fluctuations.

In addition, in order to reduce the time delay and keep the steam common main pipe pressure constant, it is possible to supply the required amount of steam directly from the high-pressure side steam main pipe by using a temperature reducing pressure reducing valve instead of going through a turbine. Although there is a method, there is a problem in that actively using this method involves energy loss.

[Purpose of the invention]

The present invention detects the steam pressure in the steam common main pipe, and based on that information, adjusts the opening of the turbine inlet steam valve in preference to the temperature reducing pressure reducing valve, and adjusts the opening accordingly to meet the required steam load. By performing boiler combustion control at the same time, the aim is to achieve stable operation of the steam system without time delay and energy loss.

[Summary of the invention]

The present invention includes a boiler having a fuel control valve for regulating the fuel to be supplied, a high-pressure side pipe for taking out high-pressure steam generated in the boiler, and a steam flow control valve connected to the high-pressure side pipe for regulating the flow rate of the high-pressure steam. , a turbine driven by high-pressure steam whose flow rate is adjusted by this steam flow rate control valve, a low-pressure side piping that takes out the low-pressure steam used in this turbine, and a turbine connected between this low-pressure side piping and the high pressure (III piping). A pressure reducing valve that forms a parallel circuit with the pressure reducing valve, a pressure detector that is connected to the low pressure side piping and measures the pressure of low pressure steam, this pressure detector, the fuel control valve and steam flow control valve attached to the boiler, and the temperature reducing valve that is connected to the low pressure side piping and measures the pressure of the low pressure steam. A process input/output device that transfers input/output signals to the pressure reducing valve, and a process input/output device that is connected to this process input/output device and controls the steam flow rate control valve and the fuel oil control valve with priority over the temperature pressure reducing valve based on the steam pressure value. This is a steam system control device consisting of an arithmetic and control device that performs arithmetic control.

That is, the present invention has a steam system consisting of a boiler, a turbine, a steam common cut pipe, and steam load equipment. This steam system control device is characterized in that the combustion in the boiler and the steam flow rate in the turbine are simultaneously controlled L2 to stabilize the pressure in the steam common main pipe.

[Embodiments of the Invention] Next, embodiments of the present invention will be described. Figure 1 shows the static pressure side steam common main pipe 6 that takes out the high pressure steam generated in the boiler 1.
, a turbine inlet steam flow rate control valve 9 connected to the high pressure side steam common main pipe 6 and adjusting the flow rate of high pressure steam, and a turbine 2 driven by the high pressure steam whose flow rate is adjusted by the turbine inlet steam flow rate control valve 9. A low-pressure side steam common main pipe 7 that takes out the low-pressure steam used in the turbine 2, and a temperature reduction and depressurization unit connected between the low-pressure side steam common main pipe 7 and the high-pressure side steam common main pipe 6 and forming a parallel circuit with the turbine 2. A valve 10 , a pressure detector 11 connected to the low-pressure side steam common main pipe 7 and measuring the pressure of low-pressure steam, the pressure detector 11 , the boiler fuel control valve 8 , the turbine inlet steam flow rate control valve, and the temperature reducing pressure reducing valve 10 A process input/output device 5 that exchanges input/output signals with
and an arithmetic control device 4 which is connected to the process input/output device 5 and performs arithmetic control to control the turbine inlet steam flow rate control valve 9 and the boiler fuel control valve 8 with priority over the temperature reducing pressure reducing valve 10 based on the steam pressure value. The figure shows a steam system control device consisting of:

A turbine 2 is supplied with steam from a boiler 1 having a boiler fuel control valve 8 and has a turbine inlet steam flow rate control valve 9.
and the high pressure side steam common main pipe 6 connected to the temperature reducing pressure reducing valve 10
and a steam system composed of a low-pressure side steam common main pipe 7 that is supplied with steam from the turbine 2 or the temperature reduction pressure reducing valve 10 and connected to the steam load equipment 3, and a low-pressure side steam common main pipe 9.
Pressure information is inputted from the pressure detector 11, which was read several times, and based on the results measured by the arithmetic and control unit 4, the boiler fuel control valve 8, turbine inlet steam flow rate control valve 9, temperature reduction and depressurization are performed. A steam system control device comprising a process input/output device 5 that outputs commands to a valve 10 is shown.

When a load change occurs in the steam load equipment 3, the low pressure side steam common main pipe 7 that directly supplies steam to the steam load equipment 3
A pressure change occurs. This pressure change is input from the pressure detector 11 via the process input/output device 5, and the arithmetic and control unit 4 determines the turbine inlet steam flow rate necessary to absorb the pressure change, and adjusts the turbine inlet steam flow rate accordingly. Valve 9
Perform the opening side q. Adjusting the turbine inlet steam flow rate inevitably changes the turbine inlet steam pressure, causing pressure fluctuations in the high-pressure side steam common main pipe 6. In order to avoid pressure fluctuations in the high-pressure side steam common main pipe 6, it is necessary to adjust the amount of evaporation in the boiler 1.The required amount of evaporation in the boiler is determined, and the amount of boiler fuel used is determined accordingly. Based on these calculation results, the turbine inlet steam flow rate control valve 9 and the boiler fuel control valve 8 are controlled by simultaneously issuing commands from the process input/output device 5. As a result of calculation, if it is determined that the pressure in the low-pressure side steam common main pipe 7 connected to the steam load equipment 3 cannot be kept constant by controlling the boiler fuel control valve 8 and the turbine inlet steam flow rate control valve 9 alone, The temperature reducing pressure reducing valve opening degree necessary to compensate for this is calculated, and a command is issued from the process input/output device 5 to control the temperature reducing pressure reducing valve 10. The control calculation procedure of the arithmetic and control device 4 of the steam system control device of the present invention is shown in FIG.

[Effects of the Invention] As explained above, according to the present invention, the steam load facility (+
In order to simultaneously control the boiler evaporation amount by the action of the boiler fuel control valve 8 and the turbine inlet steam flow rate by the action of the turbine inlet steam control valve 9 against load fluctuations in the ijt 3, pressure fluctuations in the low-pressure side steam common main pipe 7 can be controlled simultaneously. It has the advantage of being able to converge in a short time and not causing pressure changes in the high pressure side steam common main pipe 6. Furthermore, since the temperature reducing pressure reducing valve 10 acts as a backup function, energy loss caused by the temperature reducing pressure reducing valve 1° is normally prevented, and is effective in increasing the safety of the entire steam system in an emergency.

As described above, the steam system control device according to the present invention has a hierarchical structure in which the first stage controls the boiler and turbine, and the second stage controls the temperature reducing pressure reducing valve, thereby minimizing energy loss and achieving reliability. can be increased.

[Brief explanation of drawings]

FIG. 1 is a system explanatory diagram showing one embodiment of the steam system control device of the present invention, and FIG. 2 is an explanatory diagram of the control calculation procedure of the arithmetic and control device of FIG. 1. 1... Boiler 2... Turbine 3... Steam load equipment 4... Arithmetic control device 5...
Process input/output device 6... High pressure side steam common main pipe 7.
...Low pressure side steam common main pipe 8...Boiler fuel control valve 9
... Turbine inlet steam flow rate control valve 10 ... Temperature reduction pressure reducing valve 11 ... Pressure detector Fig. 1 Fig. 2

Claims (1)

[Claims] A high-pressure side pipe that takes out the high-pressure steam generated in the boiler, a steam flow control valve that is connected to this high-pressure side pipe and adjusts the flow rate of the high-pressure steam, and a turbine that is driven by the high-pressure steam whose flow rate is adjusted by the steam flow control valve. and a low-pressure side pipe for extracting low-pressure steam used in the turbine, a temperature reducing pressure reducing valve connected between the low-pressure side pipe and the high-pressure side pipe and forming a parallel circuit with the turbine, and a low-pressure side pipe connected to the low-pressure side pipe. , a pressure detector that is connected and measures the pressure of low-pressure steam, and a process input/output that exchanges input/output signals with the pressure detector, the fuel control valve attached to the boiler, the steam flow rate control valve, and the temperature reducing pressure reducing valve. It consists of a bag (d) and an arithmetic control device connected to the process input/output device that performs arithmetic control to control the steam flow rate control valve and the fuel control valve in priority to the temperature reducing pressure reducing valve based on the steam pressure value. Steam system control equipment.