JPS61180804A - Method of controlling temperature of steam of boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling steam temperature in a boiler.

[Conventional technology]

The manipulated variables for controlling the boiler steam temperature include the amount of spray for the attenuator, the burner tilt angle, the amount of recirculated gas, etc., but monitoring of these manipulated variables for steam temperature control has not been done conventionally.

[Problem that the invention seeks to solve]

Therefore, there have been problems in that it takes time to prevent water damage when steam temperature control malfunctions, and that when a certain manipulated variable is extremely unbalanced, there is almost no margin for control.

[Failure to solve the problem]

The present invention was made to solve the above-mentioned problems, and it monitors multiple manipulated variables for controlling steam temperature, and when one manipulated variable deviates from the range of the control plan value, the same manipulated variable is forced. To provide a method for controlling steam temperature in a boiler, which is characterized in that the steam temperature is replaced by another manipulated variable by temporarily returning the temperature to within the range of a control plan value.

[For production]

As mentioned above, by monitoring multiple manipulated variables that control steam temperature and returning those that deviate from the control plan value range to within the control plan value range, all manipulated variables are always kept within the control plan value. The operation is continued in a state where each operation amount of control 1 has a margin.

〔Example〕

An embodiment in which the present invention is applied to a coal-fired boiler will be described based on the drawings.

The manipulated variables for controlling the superheated steam temperature or reheated steam temperature of a coal-fired boiler include the attenuator spray amount (hereinafter referred to as "SH spray amount"), burner tilt angle, recirculation gas amount, and excess air ratio. . In addition, in a coal-fired boiler that co-fires or exclusively burns multiple types of coal, the steam temperature can be adjusted by changing the coal types and co-firing ratio. In addition, a superheater is added to the suit prower.

It is also possible to aid in steam temperature control by removing and crushing heat transfer surfaces such as reheaters and changing the amount of heat absorbed by each heat transfer surface.

The operation amount for controlling the steam temperature is constantly monitored by appropriate measuring means and stored in the computer. On the other hand, each manipulated variable is set with a control plan value range (between an upper limit value and a lower limit value) according to the boiler load during normal operation.

The drawing shows an example in which the control plan value and the current manipulated variable are displayed on a CRT screen. In the figure, 1 is the boiler load, 2 is the reheat steam temperature, 3 is the exhaust gas concentration, 4 is the amount of recirculated gas introduced to the bottom of the furnace, 5 is the amount of recirculated gas introduced to the burner section, and 6 is the nozzle. (- indicates the tilt angle. In each graph, a is the upper limit of the control plan value for each manipulated variable, b is the lower limit, and C is the current value. In the graph, the current value C of the recirculation gas amount 4 is Since it is below the lower limit value, operate the damper to keep it within the control plan value.As a result, the amount of recirculated gas increases and the reheat steam temperature rises slightly, but the reheat steam temperature If it is within the range of the control plan value, the operation continues as it is. If the reheat steam temperature exceeds the upper limit value a, other manipulated variables are adjusted to lower the reheat steam temperature. For example, , the combustibility in the furnace is improved by increasing the excess air ratio (increasing the concentration of exhaust gas 02), and the amount of heat absorbed by the reheater is decreased by increasing the amount of heat absorbed in the furnace.

The relationship between increases and decreases in superheated steam temperature and reheated steam temperature and each manipulated variable is shown in the following table.

Among these, the coal type or coal blend ratio is 9. For example, if you change it to improve the combustibility in the furnace, the amount of heat absorbed in the furnace will increase, and as a result, the amount of heat absorbed in the superheater and reheater will decrease. It is something.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of manipulated variables for controlling steam temperature are monitored, and those that deviate from the range of the control plan value are forcibly returned to the range of the control plan value. The total amount of operation is always kept within the control plan value, and operation continues with each control amount of control 1 having a margin. When the steam temperature itself deviates from the range of the control plan value as a result of the above operation, it is possible to replace it with other manipulated variables with a margin of control within the range of the control plan value.

Additionally, the above monitoring makes it extremely easy to check for abnormalities.
When steam temperature control is out of order, by displaying changes over time in data stored in a computer on a CRT screen, it is possible to quickly determine the amount of water causing the problem and take countermeasures.

[Brief explanation of drawings]

The drawing is an explanatory diagram showing an example of display on a CRT screen that is superior to one embodiment of the present invention. 1... Boiler load, 2... Reheat steam temperature, 8...
Exhaust gas 02 concentration, 4.5... Recirculation gas amount, 6...
Burner tilt angle. Figure 1: 1982 Patent Application No. 111737 2 Name of the invention: Method for controlling boiler temperature III 3 Relationship with the person making the amendment Patent applicant's address 2-5 Kunouchi, Chiyoda-ku, Tokyo Number 1 name (62
0) Mitsubishi Heavy Industries, Ltd. Address: 254 Kunouchi-8-chome, Chiyoda-ku, Tokyo Name: Electric Power Development Co., Ltd. 4, Agent Φ September 25, 1980 The power of attorney will be supplemented as shown in the attached sheet. "The drawing is" on page 6, line 17 of the specification is corrected to "Fig. wa". Correct the attached drawings.

Claims (1)

[Claims] Multiple manipulated variables that control steam temperature are monitored, and when one manipulated variable deviates from the control plan value range, the other manipulated variables are forcibly returned to within the control plan value range. A method for controlling steam temperature in a boiler, which is characterized by changing the temperature of steam in a boiler.