Method for controlling combustion process of circulating fluidized bed boiler on basis of multivariable generalized predictive control optimization

Abstract

The invention provides a method for controlling the combustion process of a circulating fluidized bed boiler on the basis of multivariable generalized predictive control optimization. The method comprises the steps that 1, the design parameters of controllers for the combustion process of the circulating fluidized bed boiler are initialized; 2, a combustion process model is built through identification of a multivariable gradual reducing memory recursive least-square method according to collected process variable data of the combustion process of the circulating fluidized bed boiler; 3, the parameters of the proportion-integration-differentiation (PID1) controller, the PID2 controller and the PID3 controller are subjected to optimal setting according to multivariable generalized predictive control characteristics, and setting results are decoupled; 4, according to the obtained parameters of the controllers, the coal feed amount, the primary air volume and the secondary air volume are controlled respectively, and therefore the bed temperature, the main steam pressure and the oxygen content of smoke of a hearth outlet are controlled; and 5, the next moment starts, and the step 2 to the step 5 are repeated. According to the method, the control precision is high, the tracking speed is high, overshooting is avoided, steady state errors are small, the anti-coupling capacity is high, and the control process is smooth; the method is a multivariable control technology, which is simple in mode and convenient to implement, for the combustion process of the circulating fluidized bed boiler.

Description

technical field [0001] The invention belongs to the technical field of boiler combustion process control, and relates to a multivariable proportional-integral-derivative (PID) control method for the combustion process of a circulating fluidized bed boiler optimized by multivariable generalized predictive control, especially a cycle optimized by multivariable generalized predictive control Fluidized bed boiler combustion process control method. Background technique [0002] Circulating fluidized bed boilers (CFBB) have the advantages of wide fuel adaptability, low-pollution combustion, and strong load regulation capabilities. In recent years, they have been more and more widely used in power generation, heating, steelmaking, and chemical industries. Combustion process is a major system of circulating fluidized bed boiler, and the control quality of combustion process directly affects the safety and economy of circulating fluidized bed boiler operation. [0003] At present, t...

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Problems solved by technology

The combustion process of circulating fluidized bed boiler is a typical multi-variable, strongly coupled, nonlinear, and complex dynamic process control system, and it is also difficult to establish an accurate mathematical model

The Chinese patent "A Multivariable Control Method for the Combustion Process of Circulating Fluidized Bed Boilers", application number CN201110422623.4, discloses a multivariable generalized predictive control method for the combustion process of circulating fluidized bed boilers. This simple multivariable generalized prediction Although the control method can theoretically improve the quality of combustion process control, since the control method is based on the description and solution of constrained optimization problems, the computer environment and training and maintenance costs are relatively high, and it is not as simple as the multivariable PID controller. It is easy to understand and master, but it is difficult to implement, and it is difficult to be practically applied to the combustion process control of circulating fluidized bed boilers

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