SU1002731A1 - Combustion process automatic control system - Google Patents

Description

The invention relates to a power system, in particular, to automatic control of the combustion process in furnaces of direct injection boilers.

It is known that the opening of the separator leaves leads to agglomeration of dust grinding, an increase in the concentration of the air mixture, an increase in the performance of the dust system and the heat load of the boiler, and a decrease in the power consumption for own needs.

A system is known for automatically controlling the performance of a mill with direct injection of dust into the furnace of a boiler. The system contains a fuel consumption regulator in the mill with a higher level system reference, a primary air regulator and a separator position regulator with appropriate sensors. In this system, an increase in the productivity of the mill is carried out by changing the fuel consumption in the mill and loading it. At the same time, flow controllers of the drying agent and separator flaps operate autonomously. Upon reaching the mill load, close to the blockage, the load controller is connected, tf first

through the integration units to the primary air controller (RPV) and with the exhaustion of the adjustment range - to the separator valve regulator (RCC). With the disadvantages of the known control system is its complexity (a special regulator of the separator valves, two integration units, three groups of keys, the logic block of switching the control actions of the fuel regulator) and low reliability (it is impossible to suspend

f5 development of an emergency situation, for example, mill blockage, with exhaustion of control ranges on the RPV and RCC). In addition, when constructing a scheme in which a task is submitted

20 to the fuel regulator, the mill operates in an economically non-optimal mode (the power consumption on its own needs increases), and the system as a whole has significant inertia, which also determines the poor quality of regulation.

Closest to the proposed technical essence is a system of automatic control of the combustion process in a boiler 30 unit with a pneumatic injection system containing fuel flow controllers in an amount corresponding to the number of mills, with sensors for loading mills and primary air flow connected to flow regulators fuel through differentials, heat load regulator with appropriate sensors and an integration unit connected to primary air regulators connected to sensors primary air flow and with executive mechanisms of primary air flow rate, equipped with regulator full opening sensors 2. The disadvantage of this automatic control system is insufficient range of air flow rate control during operational limits (for example, by the number of working mills, primary air flow and etc.). The purpose of the invention is to expand the range of controlling the flow rate of the air-fuel mixture while ensuring the economically optimal operation of the mills, high mobility of the object and efficiency of combustion. The goal is achieved by the fact that the system of automatic control of the combustion process in the boiler unit with a direct-injection dust system, containing fuel consumption controllers in an amount corresponding to the number of mills, with sensors for loading mills and primary air consumption, connected to fuel consumption controllers through the differentiators , a heat load controller with appropriate sensors and an integration unit connected to the primary air regulators connected to the primary air flow sensors Xa and with actuators of primary air flow, equipped with sensors for fully opening the regulator, additionally contains actuators and separator flap positions, equipped with sensor and flap positions, mode selectors with groups of normally closed and normally open contacts and two logical elements of type I, the outputs of the primary air regulators are connected through a group of normally closed contacts to the executive mechanisms of the primary air flow rate, the sensor full opening of the regulating body of which are connected to the inputs of the first logic element, and whose output is connected to devices for selecting the mode, and through a group of normally open contacts to the actuators of the separator doors, position sensors of which are connected through normally open contacts to the inputs of the primary regulators air and to the inputs of the second logic element, the output of which is connected to the device selection mode. The drawing shows a block diagram of an automatic control system for the combustion process. The system contains controllers 1 for the consumption of raw fuel in the mills, in an amount corresponding to the number of mills, with actuators 2 changes in the fuel consumption in the mills, with sensors 3 loading mills (amount of fuel), for example, the active power of driving engines, and tori 5 primary air flow (RPV) with sensors 6 primary air flow in mills and with actuators 7 primary air flow, which are equipped with sensors 8 to fully open the regulator heat load torus 9 with heat generation sensor 10., with feedwater flow sensor to boiler 11, with differentiator 12 and integration unit 13, mode selection devices 14 actuators 15 for changing position of cages of separators with position sensors 16, logic gates 17 and 18 of type II with the corresponding outputs 19 and 20 of the control unit 14. The sensors b of the primary air flow rate in the mills are connected to the controllers 1 by means of differentiators 4, the sensor 11 of the water flow is connected to the individual inputs of the regulator 9 by means of the differentiator 12. The outputs of the integration unit 13 are connected to the individual inputs of the regulators 5. The outputs of the regulators 5 are connected via normally open contacts of devices 14 to the corresponding actuators 15, which are equipped with sensors 16 of the position of the cages of the separator, and through normally closed contacts of devices 14 - to actuators 7, equipped with sensors 8 for full opening of the regulatory body. The outputs of the sensors 8 are connected to the logic element 18. The outputs 19 and 20 of the corresponding logic elements 17 and 18 are connected to the devices 14 in parallel. The output 19 is for triggering the mode selectors 14, and the output 20 for restoring the normal mode. The system works as follows. Regulators 1 stabilize the amount of fuel in the mill, ah (loading of the mills) at a given economically optimal value by signals from the respective sensors 3. Regulators 1 act on

actuators 2 changes the fuel consumption in the mills, changing the fuel supply.

The regulator 9 perceives the change in the heat gap from the sensor 10 or the change in load from the sensor 11 and the speed of its change from the differentiator 12, by means of the block 13 and by means of the regulators 5 of the primary air per mill changes the total flow of primary air in the mills and accordingly The consumption of air mixture into the furnace of the boiler (the mixture of air mixture in this scheme is proportional to the flow of primary air) by acting on the executive mechanisms 7 of the regulating bodies of the flow of primary air. The device 14 provides the connection of the regulator 5 to the actuator 7. Introduction of the signal to the circuit of regulators 1 on the rate of change of the primary air flow rate into the mill from the differentiators 4 improves the quality of controlling the fuel consumption in transient conditions and accordingly stabilizes the consumption of coal dust in the air mixture .

When the primary air consumption ranges are exhausted, the automatic limiting load is automatically memorized, and the inputs of the logic element 17 receive signals from the sensors 8 to fully open the primary air flow regulating elements. If the adjustment ranges are exhausted at all mills (the signal came from all sensors 8, working mills), logic element 17 through output 19 switches devices 14, disconnecting actuators 7 from the output of regulators 5 and connecting actuators 15 with position sensors 16 regulatory body. Let the signal from block 13, characterizing the current value of the load, grow, i.e. A further increase in heat generation (boiler heat load) is required. Then, the controller 5, perceiving this change, will begin to open the separator flaps. This will lead to an increase in the generation capacity of the fuel layer in the mills due to a change in the properties of the separation zone and the transporting capacity of the drying agent due to a decrease in the resistance of the dust-air tract. As a result, the finished dust consumption will increase. The drain to the boiler furnace, regulators 1, perceived changes in the load of the mills from sensors 3 and the consumption of the drying agent from differentiators 4, will increase the flow of fuel to the mills (inflow), the temporary deviation of their load at a given value,

The second was due to an increase in the flow of finished dust into the furnace. In general, this provides compensation for the required increase in heat load.

Compensation of the signal from block 13 on the regulators 5 occurs as a result of the increment of the corresponding signal from the position sensors 16. At the optimal position of the separator flaps, the signal from the hard feedback sensor 16 is zero (absent and increases as the position of the separator flaps changes from optimal to full open.

By reducing the heat load of the boiler, the controller 5 restores the optimal position of the cages of the separators. In this case, the logic element 18 through the output 20 forms the switching of the devices 14 to the initial position corresponding to the normal mode of operation. Hard feedback sensors 16 on the RPT are also turned off.

Claims (2)

1. USSR author's certificate according to the application No. 2930668, cl. F 23 N 1/02, 1980. 2. Authors certificate of the USSR 794299, cl. F 23 N 1/02, 1979.