SU1657879A1 - Method of automatic control of combustion process - Google Patents

Abstract

The invention relates to the regulation of the combustion process during staged combustion of fuel, mainly in steam generators that burn solid fuels. The purpose of the invention is to improve the quality of the combustion process and reduce emissions of nitrogen oxides into the atmosphere during the staged combustion of solid fuels, mainly in the furnace of the steam generator, which has upper and lower burners and the afterburning zone. The method allows independent supply of air to each of the combustion stages and to the afterburning zone, and the total air flow to the furnace is varied according to a parameter that characterizes the efficiency of the combustion process by influencing the fan guides of the blowers. The change in the flow of air into the main combustion zone is made by the load of the boiler, with the possibility of changing this dependence by the operator, and the rest of the air is supplied to the reducing combustion zone and to the afterburning zone redistributed between them according to the content of nitrogen oxides in the flue gases. so that the amount of emissions is at a level not exceeding a predetermined value. 1 il. w Ё

Description

The invention relates to the regulation of the combustion process during staged combustion of fuel, mainly in steam generators that burn solid fuels.

The aim of the invention is to improve the quality of regulation of the combustion process and reduce emissions of nitrogen oxides into the atmosphere, mainly during the staged combustion of solid fuel in the furnace of a steam generator having upper and lower burners and the afterburning zone.

The drawing shows the control system diagram for the implementation of the proposed method

The system contains a common air regulator 1, to the inputs of which fuel consumption sensors 2 and air 3 are connected through an air preheater, a correction device 4 and a dynamic communication device 5. The correction device 5 is connected with the setting device 6 and the sensor 7 of the parameter characterizing the efficiency of the combustion process, and the dynamic communication device 5 is connected to the integrating communication device 8. The regulator 1 is connected to the guides of the blower fans 9, the system also contains controllers 10-12 connected to the regulating bodies 13-15 of the air supply to

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vj with

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lower and upper Rusa burners and in the afterburning zone. The controller 10 is connected to the sensor 3 through a device 16 percent dividing the signal and with the sensor 17 air flow to the lower r of the burners.

The controller 11 is connected to the sensor 3 through the device 18 percent dividing signal, with the sensor 19 to the upper flow rate of the burners and to the correction device 20. The controller 12 is connected to the sensor 21 of the total air flow in the afterburner, the correction device 20 and through the device 18 with a sensor 3. A correction device is connected to a sensor 22 and a sensor 23 for the concentration of nitrogen oxides in flue gases. The system also contains analog controllers 24 and 25, which are connected with devices 16 and 18, with a device 26 for manually redistributing the performance of systems for infinitely variable control of fuel flow to the upper and lower runners of the burners, through device 8 with a regulator 27 for the steam generator heat load. Regulators 24 and 25 are connected to systems 28 and 29 of the stepless control of the fuel supply to the upper and lower Russ.

The method is carried out as follows.

The common air regulator 1 receives the signal from the fuel consumption sensor 2, the air consumption sensor 3 through the air preheater, the corrective device 4 and the dynamic communication device 5.

The correction device 4 receives signals from the setting device 6 and the sensor 7 of the parameter characterizing the efficiency of the combustion process, and the dynamic communication device 5 receives the signal from the integrating communication device 8 with a heat load controller. The common air regulator 1 acts on the fan guides of the blower fans 9.

Regulators 10-12 provide independent air supply with the help of regulators 13-15, respectively, in the lower and upper Russ and in the afterburning zone. The controller 10 receives signals from the flow sensor 3 through a device 16 percent dividing the signal from the air flow sensor 17 into the lower rus.

The controller 11 receives signals from the air flow sensor 3 through the device 18, the percentage of the signal division, the air flow sensor 19 in the upper power unit and the correction device 20.

The controller 12 receives signals from the air flow sender 3 through the device 18 percent division of the signal, the sensor 21 of the total air flow to the afterburning zone and the correction device 20. The latter receives signals from the setting unit 22 and the sensor 23 of the nitrogen oxide concentration in the exhaust gases. Analog Controls 24

and 25 receive signals from devices 16 and 18 percent dividing the signal by total air flow, an integrating communication device 8 with a heat load controller and a device 26 for manually redistributing the performance of infinitely variable lower and upper arm systems.

The integrator 8 receives a signal from the heat load controller 27.

Regulators 24 and 25 act respectively on systems 28 and 29 of infinitely adjustable lower and upper arm. During operation, the common air regulator 1 changes the performance of the blower

fans, maintaining the ratio of total fuel consumption and air given by setting unit 6 of the correction device 4. Changes in the ratio caused by changes in fuel consumption and

air, are eliminated by regulator 1 due to signals from fuel consumption sensors 2 and air 3.

Introduction to the regulator system of the dynamic link device 5 eliminates the movement of the fuel and air regulating bodies in opposite directions in case of internal disturbances. Under the action of the signal from the sensor 7 parameter, which characterizes the efficiency of the combustion process,

the correction device 4, when the signal size deviates from the specified value, changes the effect on the regulator 1, which sets the required value of the excess air in the furnace by acting on

guides of blower fans.

The distribution of air flow between TGizhn them and the upper Rus burners

5 is carried out as a function of the load by the regulators 10 and 11 in such a ratio established by the devices 16 and 18 percent of the division of the signal so that the air supplied to the lower

0 rus, was in stoichiometric, and in the upper - below the stoichiometric ratio with respect to the fuel supplied to the lower and upper rus, respectively, with the possibility of changing this dependence by the operator through the device 26, affecting the similar regulators 24 and 25. which redistribute the fuel between the lower and upper tiers of the burners with the help of systems 28 and 29 of stepless regulation

The air supplied to the upper rus is divided between the burners of this Russ and the nozzles of the sharp afterburning of the afterburner zone by the regulator 12 through the correction device 20 for the content of nitrogen oxides in the flue gases, which receives signals from the setting unit 22 and the sensor 23, and as the furnace chambers, the flow to the nozzles of the sharp blowing of the afterburning zone decreases in proportion to the reduction in load.

Claims (1)

The invention method of automatic control of the combustion process by measuring fuel consumption and total air and maintaining a given value of the ratio of fuel to air by changing the performance of blow fans with a correction parameter that characterizes the efficiency of the combustion process, and the content of nitrogen oxides in the exhaust gases, different what with the purpose improving the quality of regulating the combustion process and reducing emissions of nitrogen oxides into the atmosphere, mainly during the staged combustion of solid fuels in The steam generator furnace, having top and bottom burners and the afterburning zone, additionally measures the heat load of the steam generator, the total air flow is adjusted by a parameter characterizing the efficiency of the combustion process, by controlling fan guides on the blowers, and by adjusting the measured heat load, the flow is controlled parts of the general air supplied to the lower rus torch, with manual correction of this dependence by the operator, and the remaining amount of air is redistributed between the upper brown torch and the afterburner zone according to the content  nitrogen oxides in flue gases until a total amount of nitrogen oxides is released to a value not exceeding a predetermined value.