Closed loop control method with low nitrogen burning for fire coal boiler

Abstract

The present invention provides a closed loop control method with low nitrogen burning for a fire coal boiler, which adopts a method for controlling grading air quantity and correcting emission concentration of nitrogen oxide to control the low-nitrogen burning process. The method includes steps as follows: automatically judging the kind of fire coal in the present fire coal boiler according with operation parameters, automatically selecting corresponding functions for setting grading air quantity according with the kind of fire coal and operating method of system equipment, thereby, processingfeedforward control to the low-nitrogen burning process; confirming a setting value of emission concentration of nitrogen oxide by using an optimal model based on economic environmental protection cost, comparing the setting value of emission concentration with a process value of emission concentration, and correcting the setting value of grading air quality according with the compared result, thereby, realizing the feedback control to the low-nitrogen burning process; generally speaking, the method provided by the invention adopts the forecast optimization intelligent feedforward and optimization feedback cascaded adjustment, which can realize the boiler operate economically, environmental-friendly and optimally in condition of changeable environment factors.

Description

technical field [0001] The invention relates to a coal-fired boiler energy-saving and emission-reduction technology, in particular to a low-nitrogen combustion closed-loop control method applied to a coal-fired boiler. Background technique [0002] According to the mechanism of nitrogen oxide generation and suppression, reduce boiler nitrogen oxide NO x Emissions must be at the cost of sacrificing unit economy. Please refer to figure 1 The simplified flow chart of the combustion control method in the prior art is shown. At present, in the domestic coal-fired boilers of power plants that adopt low-nitrogen combustion technology, the method of adjusting the air volume of graded air is generally used to control the emission of nitrogen oxides in the combustion process, namely Use the load command-graded air volume setting function F(X) to set the adjustment amount—the graded air volume value (step S10), take the actually measured graded air volume as the process value, and th...

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Problems solved by technology

[0003] Since the above method does not include the control of the adjusted parameter - boiler nitrogen oxide emission concentration -, it is essentially an open-loop feed-forward control method, and this control strategy is not suitable for boiler coal quality. Ability to achieve optimal control of boiler economy and emission costs under changes in factors such as unit load, system equipment operation mode, etc.

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