Peak-adjusting gas-fired boiler water supply flow and pressure double-balance type control system

Abstract

The invention discloses a peak-adjusting gas-fired boiler water supply flow and pressure double-balance type control system. The peak-adjusting gas-fired boiler water supply flow and pressure double-balance type control system is used for controlling the double balance of a water supply flow and pressure among a boiler drum and a variable-frequency water feeding pump and a power-frequency water feeding pump; when the variable-frequency water feeding pump is connected with an outlet pipeline of the power-frequency water feeding pump, the boiler drum is connected through a water feeding pipe; the system comprises an acquisition module, a control module and an execution module, wherein the acquisition module is used for acquiring a water supply flow signal, a water supply pressure signal, a boiler drum liquid level signal and a boiler drum pressure signal; the control module is used for generating a control signal of the water flow and the pressure according to the signal fed back by theacquisition module, and the execution module is controlled to perform operation; the execution module controls the running frequency of the water feeding pump and the opening and closing of a water supply adjusting valve according to the control signal of the control module. According to the system, the pressure and flow tracking adjustment can be realized, adjusting precision and response speed are improved, the tracking and adjusting controlling performance of boiler load fluctuation in a peak-adjusting process of a water supply system is better, and the operation working condition is stabilized.

Description

technical field [0001] The invention relates to a boiler control system, in particular to a peak-shaving gas-fired boiler feedwater flow and pressure double-balanced control system. Background technique [0002] In the technological process of iron and steel smelting, the production process of coke oven, blast furnace and converter will produce a large amount of surplus gas, which is a high-quality secondary energy source and is of great significance to the cost control, energy saving and emission reduction of the production line. Through the thermal power stations supporting the iron and steel enterprises, making full use of surplus gas for power generation and heat supply, the internal integration of the steel and thermal power industries can be achieved, and greater economic benefits can be achieved. However, the output of secondary energy is limited by the production status of the main production line. Due to the original fluctuation of the fuel supply status, the operat...

AI Technical Summary

Problems solved by technology

[0004] (1) The boiler water supply system mainly relies on regulating valves and return valves to adjust the water supply flow. When the boiler is operating at low load, the pressure difference between the front and back of the valve exceeds 4MPa. If the pressure difference is too large, the equipment will be washed and damaged, which will easily cause leakage and cause safety hazards. The personal safety of operators, frequent maintenance of equipment increases maintenance costs and reduces production efficiency;

[0005] (2) When the boiler is operating at low load, the pressure difference between the front and rear of the regulating valve is too high, which causes the internal throttling parts of the valve to be washed out and deformed, which affects the tightness and operational flexibility of the equipment, and the failure rate is high;

[0006] (3) Frequent fluctuations in the load of peak-shaving gas-fired boilers cause local pressure in the system. Affected by alternating stress, the high-pressure water supply system is prone to leakage, resulting in personal safety hazards such as shocks and burns;

[0007] (4) In the low-load operation state, the boiler feed water pressure does not match the main steam pressure, and the adjustment needs to be completed through the cooperation of recirculation and pressure regulating valves. The operation process is complicated, and the inappropriate coordination will affect the stable operation of the equipment;

[0008] (5) During the main steam flow and pressure fluctuation process of the boiler, the feed water flow is adjusted synchronously to stabilize the drum liquid level, the throttling adjustment method has poor linearity, small adjustment range, and insufficient accuracy;

[0009] (6) During the peak-shaving operation, the feedwater pump maintains the rated speed operation, and the feedwater pump does not track and match after the operating parameters are reduced under low load conditions, and the energy utilization efficiency is low

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