Control method of combustion system of circulating fluidized bed boiler

Abstract

The invention relates to a control method of a combustion system of a circulating fluidized bed boiler, which adopts multivariable expert intelligent self-calibration PID control and is provided with an on-line calculation module for the static characteristics of the circulating fluidized bed boiler. The on-line calculation module for the static characteristics of the circulating fluidized bed boiler calculates the coal supply quantity, the limestone quantity and the deslagging quantity for realizing the optimizing combustion of the boiler under different loads, the primary air quantity and the secondary air quantity are optimized and proportioned and are used as load feedforward signals which are applied to a main steam pressure control loop, a limestone quantity control loop, a bed pressure drop control loop, a bed temperature control loop and an oxygen quantity control loop, and each control loop adopts an expert intelligent self-calibration PID controller to form a multivariable combustion control system of a CFB boiler. The invention is provided with the calculation module for the static characteristics of the circulating fluidized bed boiler, which can accurately send out each regulation quantity instruction at real time and realize automatic control; the multivariable expert system is in consideration of the nonlinearity and the strong-coupling property of the combustion system of the boiler and ensures the performance robustness of the control system; and meanwhile, the PID parameters are automatically regulated according to the change of the characteristics of a controlled object, so the automatic combustion control system of the circulating fluidized bed boiler has stable robustness.

Description

technical field [0001] The invention relates to a circulating fluidized bed boiler expert intelligent self-tuning PID control method, in particular to a circulating fluidized bed boiler multivariable expert intelligent self-tuning PID control method based on static characteristics. Background technique [0002] Circulating fluidized bed combustion technology is one of the clean coal combustion technologies. Coal and desulfurizers (such as limestone) are added to the bed of the combustion chamber, and the bed is suspended by blasting from the bottom of the furnace for fluidized combustion. Today, when environmental protection is attracting attention, the inherent cheap desulfurization technology in the furnace of fluidized bed combustion and the low NO X emissions, making circulating fluidized bed boilers the preferred thermal equipment in high-sulfur coal areas. [0003] Although circulating fluidized bed (CFB) boilers have been put into commercial operation in large quanti...

AI Technical Summary

Problems solved by technology

For the CFB boilers currently in service, although the commissioning personnel gave the relationship between the amount of fuel B and the load R when the boiler was started and debugged: B 给定 =f(R), also gives the relationship between primary air volume and secondary air volume with load R: Q 1给定 = f(R), Q 2给定 =f(R), these functions are all determined by the load command and fuel volume curve, load command and primary air volume curve, load command and secondary air volume curve obtained from the field test, but these curves are for the test coal type and its specific For coal particle size, when the coal particle size and coal type change, the coal combustion rate and calorific value change, and the distribution curve of primary air volume and secondary air volume also changes, although some units are supplemented by calorific value correction Or the main steam pressure correction to consider the change of coal type, but the correction of the coal calorific value can only adjust the coal supply but cannot correctly match the primary and secondary air volumes for optimal combustion according to the changed coal quality and particle size distribution. The inability to give the setting values ​​of each adjustment amount in time greatly limits the variable load rate of the CFB unit. At the same time, the effects of limestone composition, bed pressure drop, desulfurization efficiency and exhaust gas temperature on coal feed, primary air volume, and secondary air volume are not considered. Influence of air volume, limestone volume, slag discharge volume and other adjustment value setting values

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