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Control method of outlet steam temperature of primary superheater based on static characteristics of superheater temperature rise

A technology of static characteristics and steam temperature control, which is applied in the control of superheated temperature, steam superheating, steam generation, etc. It can solve the problems of increased share of dynamic correction value, no consideration, and decrease of share of feedforward value, etc.

Inactive Publication Date: 2019-03-01
ZHEJIANG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The method of constructing the reference value function of the leading steam temperature according to the temperature rise characteristics of the steam passing through the superheater does not consider the change of the leading steam temperature setting value caused by the change of the primary steam temperature setting value during operation. With the change of temperature setting value, the deviation between the reference value of the leading steam temperature and the actual leading steam temperature value increases, the share of the feedforward value in the output of the main regulator decreases, and the share of the dynamic correction value increases, which affects the leading steam temperature. The adjustment quality of the steam temperature leads to an increase in the fluctuation of the primary steam temperature
[0008] According to the method of boiler thermal calculation to form the reference value function of the leading steam temperature under different loads, after long-term operation or maintenance of the boiler, due to changes in the thermal characteristics of the boiler, there will be a large deviation between the reference value of the leading steam temperature and the actual leading steam temperature value , which reduces the feedforward effect of the main regulator and affects the adjustment quality of the leading steam temperature
At the same time, this method does not consider the influence of the change of the primary steam temperature setting value on the change of the leading steam temperature setting value when the boiler is running.

Method used

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  • Control method of outlet steam temperature of primary superheater based on static characteristics of superheater temperature rise
  • Control method of outlet steam temperature of primary superheater based on static characteristics of superheater temperature rise

Examples

Experimental program
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Effect test

Embodiment 1

[0029] Such as figure 1 As shown, A is the set value of primary steam temperature; B is the load command; RAG is the load command limit module, so that the load command is within the allowable load range of the unit; SUB is the subtraction module; FG is the superheater temperature rise and load command static The characteristic function generates the corresponding leading temperature value; FOM is the first-order inertia module, and the time constant is determined according to the dynamic response time of the first-order steam temperature to the load command; HLM is the high and low limit module, so that the leading temperature setting value is allowed range; FF is the main regulator feed-forward input.

[0030] The "load command (after frequency correction)" signal is sequentially passed through a limiter module, a function generator module and a first-order inertia module, and then subtracted from the first-stage steam temperature set value to generate the feed-forward stati...

Embodiment 2

[0032] Such as figure 2 As shown, A is the set value of primary steam temperature; B is the load command; RAG is the load command limit module, so that the load command is within the allowable load range of the unit; SUB is the subtraction module; FG is the superheater temperature rise and load command static The characteristic function generates the corresponding leading temperature value; FOM is the first-order inertia module, and the time constant is determined according to the dynamic response time of the first-order steam temperature to the load command; HLM is the high and low limit module, so that the leading temperature setting value is allowed range; FF is the main regulator feed-forward input.

[0033] The "load command (after frequency correction)" signal is sequentially passed through a limiter module, a first-order inertia module and a function generation module, and then subtracted from the first-stage steam temperature set value to generate the feed-forward sta...

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Abstract

The invention discloses a primary superheater outlet steam temperature control method based on a superheater temperature rise static characteristic. The superheater temperature rise characteristic can be changed due to coking, burn deflecting and the like occurring to a boiler superheater, and in order to make the main steam temperature meet requirements, the primary steam temperature set value needs to be correspondingly adjusted during operating. A common primary steam temperature control system before-guide steam temperature feedforward value is generated only according to a load command, the situation that the before-guide steam temperature set value is changed due to the fact that the primary steam temperature set value is adjusted is not considered, and thus, the fluctuation of the primary steam temperature is increased. According to the piecewise linear steady relation between the built load command (after frequency correction) and the primary superheater temperature rise, the situation that fuel quantity change caused by change of the load command has delay action on influence of the primary steam temperature is considered, the primary superheater temperature rise value is subtracted from the primary steam temperature set value to get a number, and the number serves as a feedforward value of a main adjuster after being subjected to the first-order inertial process.

Description

technical field [0001] The invention belongs to the field of temperature control of superheated steam of a boiler of a coal-fired unit, and the technology relates to a method for controlling the outlet steam temperature of a primary superheater based on the static characteristic of temperature rise of the superheater. Background technique [0002] The steam temperature at the outlet of the primary superheater of the coal-fired unit boiler is controlled by cascade PID. A cascade PID control system consists of a main control loop and a secondary control loop. The regulator in the main loop is called the main regulator, and the regulator in the secondary loop is called the sub-regulator. [0003] The main regulator generates the set value of the secondary regulator according to the measured value of the steam temperature at the outlet of the primary superheater (hereinafter referred to as the primary steam temperature), the set value of the primary steam temperature and the fee...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F22G5/12
CPCF22G5/12
Inventor 赵均杨震力冯晓露张政江赵伟杰
Owner ZHEJIANG UNIV