SU1710947A1 - Method of automatic combustion control in furnace with recirculating fluidized bed - Google Patents

Abstract

The purpose of the invention is to improve the quality of control of combustion in the furnace at variable modes of its operation. The goal is achieved by additionally measuring the bed temperature, and the recycle flow rate affecting the distribution of solids between the firebox and the ash bin is controlled by the bed temperature and the primary air flow. 1 il.

Description

The invention relates to the field; automatic control in circulating fluidized bed furnaces and 1 can be used in station and industrial power engineering.

Methods are known for automatic adjustment in fluidized bed furnaces. .-..-: ..: v

The disadvantage of the known methods. is the inertia of the regulating effect of ASR on fuel and air consumption on the change in the load of the boiler due to the large storage capacity of the inert material, which is V

constitutes the bulk of the bed.

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The risk of uneven temperature distribution in the furnace and in the system of recycling of solid particles when the boiler operates in a variable mode increases the potential. damage to the structure of the circulating fluidized bed (danger.

slagging) and reduces the degree of capture V0g ,.

The introduction of an additional signal on the air flow rate and the temperature of the circulating fluidized bed fed to the recirculation controller will contribute to the optimal distribution of solid particles between the furnace and the ash bin.

The purpose of the invention is to improve the quality of regulation of the combustion process in circulating fluidized bed furnaces with a variable mode of operation. . ,

This goal is achieved by additionally measuring the air flow rate and the bed temperature and sending these signals to the recirculation flow controller, which regulates the distribution of solid particles between the furnace and the ash bin.

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The drawing shows the ASR burning scheme that implements the proposed method.

The ACP contains a heat load regulator 1, the input of which receives signals from the primary air flow rate sensor 2 and the drum pressure rate meter 3, the regulator body k of the regulator 1 changes the primary air flow rate. The signal from the air flow sensor 2 is supplied to the regulator 5 of the primary fuel air ratio, to another input of which a signal from the fuel consumption sensor 6 arrives and a correction signal from the differential pressure ratio block 7 on the gas distribution grid 8 to the fluidized bed pressure differential 9. Regulator 5 acts on regulator 1.0, which changes fuel consumption. Correction supported by the ratio. Neither fuel — primary air is effected by a signal from dividing unit 7 in relation to the differential pressure on the grid to the differential pressure in the fluidized bed. The controller 11 of the efficiency of the combustion process receives signals from the sensor 12 of the secondary air flow rate, the sensors 13 and C of the steam flow rate and the pressure in the drum and the correction signal from the sensor 15 of oxygen content in the exhaust gases. Regulator T6 regulator k changes the secondary air flow. The recirculation controller 17 receives a signal from the air flow sensor 2 and the fluidized bed temperature sensor 18.

The system works as follows.

When the heat load changes, the pressure in the drum changes, the signal from the speed meter 3 changes the pressure in the drum to the input of the heat load controller 1, where it is compared with the signal from the sensor 2 of the primary air flow. The regulator 1 changes the position of the regulator 7. When the primary air flow rate changes, regulator 5 of the fuel-air ratio receives an imbalance signal and regulator 5 acts on regulator 10 by changing the fuel consumption. Correction of the maintained fuel to primary air ratio is effected by a signal from a block.

15

20

25

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7 by the pressure differential across the grid to the pressure drop in the fluidized bed.

The combustion efficiency controller 11 maintains the fuel-secondary air ratio, where the heat pulse is generated as a sum of signals for steam consumption and the derivative of steam pressure in the drum, and this ratio is corrected by a signal from oxygen sensor 15 in the exhaust gases.

The controller 11 acts on the regulator 16 by changing the flow of secondary air in the right direction.

The recirculation controller 1.7 controls the distribution of solids between the furnace and the ash bin.

The proposed control method can be implemented on a steam boiler equipped with a circulating fluidized bed furnace both in station and in industrial power engineering.

To the input of the heat load controller G (the contour type P 25 regulator) signals of the primary air flow rate sensor 2 (0.15 m3 / s, sensor type DC 03702, measuring limit 630 kgf / m2) and measuring pressure rate 3 are received. drum (MZTA differential type DP - T, pressure 0.8 MPa).

Regulator A of Regulator 1 changes the flow rate of the primary air. The signal from the air flow sensor 2 is supplied to the controller 5. (controller P 25 of the Contour system), the fuel ratio is the primary air, to which another input receives the signal of the fuel consumption sensor 6 (0.039 kg / s, sensor UKS-1) and a correction signal of the 7-division unit (OBD of the MZTA system) of the ratio of pressure drop on the gas distribution grid (600 Pa, DM-type sensor, measuring limit 160 kgf / m2) to the fluidized bed pressure differential (5000 Pa, DM-type sensor, limit measurements

thirty

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630 kgf / m2). The regulator 5 (type P 25 of the Contour system) acts on the regulator 10, which changes the fuel consumption.

The efficiency of the combustion process (type P 25 of the Contour system) is received from the secondary air flow sensor 12 (0.15 m3 / s, sensor type DKO 3702,

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Reda Ktor V .. Bug Rinkova

Tehred m. Didyk

Order 330 Draws Subscription

8NIIPI of the State Committee for Inventions and Discoveries of the USSR USSR Committee 113035, Moscow, Zh-35, Raushsk nab., V-5,

Proofreader M.Samborsk

Claims (1)

POSITION A method of automatically regulating the combustion process in a furnace with a recirculating fluidized bed by measuring the ratio of the pressure drop across the air distribution grid to the pressure drop across the fluidized bed, fuel consumption, primary air flow and controlling the latter in terms of the rate of change of steam pressure and secondary air by pressure in the boiler drum and flow rate steam with correction for the oxygen content in the flue gases, with the fact that, in order to increase the accuracy of regulation of combustion in the furnace with variable modes of its operation, additionally measure the temperature of the layer, and the flow rate of recycling, affecting the distribution of solid particles between the furnace and the ash bin, is regulated by the temperature of the layer and flow