Automation of the lime kiln loading process

Control system (CS) for automatic loading of a lime kiln

The control system is designed to provide automatic and manual control of actuators that load the lime kiln and control the parameters of lime production. Actuators are shown in picture 1

1. Electric motor of the skip lift winch – 37 kW.

2. Electric motor for driving the damper of the weighing hopper – 2.2 kW.

3. Feeder drive electric motor – 2.2 kW.

4. Electric motor for driving the furnace loading hatch damper – 2.2 kW.

5. Electric motor of the smoke exhauster – 22 kW.

6. Electric motor for driving conveyor conveyor No. 1 – 2.2 kW.

7. Electric motor for driving conveyor conveyor No. 2 – 2.2 kW.

8. Electric motor for driving conveyor conveyor No. 3 – 2.2 kW.

9. Electric motor for driving conveyor conveyor No. 4 – 2.2 kW.

To operate the lime kiln loading control system and monitor its operating parameters, position sensors, temperature sensors and vacuum sensors must be installed. The location of the sensors on the furnace is shown schematically in pic. 2

1. Sensor for closing the cover of the intermediate hopper of the furnace – 2 pcs. (primary and backup).

2. Sensor for opening the oven loading hatch.

3. Sensor for closing the furnace loading hatch.

4. Vacuum sensor in the exhaust gas system.

5. Exhaust gas temperature sensor.

6. Temperature sensor No. 1 in the combustion zone.

7. Temperature sensor No. 2 in the combustion zone.

8. Temperature sensor No. 3 in the combustion zone.

9. Temperature sensor No. 4 in the combustion zone.

10. Temperature sensor No. 5 under the burners.

11. Temperature sensor No. 6 under the burners.

12. Temperature sensor No. 7 under the burners.

13. Temperature sensor No. 8 under the burners.

14. Lower position sensor for skip hoist (skip in loading position).

15. Vacuum sensor in the combustion zone.

16. Sensor for opening the bottom of the weighing hopper.

17. Sensor for closing the bottom of the weighing bin.

18. Force measuring sensor 1.

19. Force measuring sensor 2.

20. Force sensor 3.

21. Force measuring sensor 4.

22. Level sensor in the furnace.

23. Temperature sensor No. 1 in the unloading area.

24. Temperature sensor No. 2 in the unloading area.

25. Temperature sensor No. 3 in the unloading area.

26. Temperature sensor No. 3 in the unloading area.

Operation algorithm for the lime kiln loading control system in automatic mode:

1. After turning on the equipment, the skip hoist rises up (the control system gives the command “skip up”) and, if there is material in it, is unloaded.

2. When approaching the intermediate hopper of the furnace, the skip lift opens the hopper cover using special brackets. The cover of the intermediate hopper is equipped with two closing sensors (main and backup, position 1 in pic. 1). After receiving a signal from the sensors about opening the cover of the intermediate hopper, a time interval is counted (determined during setup) and a signal is sent to turn off the skip hoist.

3. After stopping the skip in the upper position, the skip unloading time is counted (set during setup, approximately 2 seconds), and after this time the “skip down” command is given.

4. After closing the cover of the intermediate hopper, a command is given to open the furnace loading hatch. The position of the loading hatch is controlled using position sensors pos. 2 and 3 (see pic. 1).

5. When the skip hoist reaches the lower position sensor (position 14 in pic. 2), the “skip down” command is turned off and the skip stops.

6. Once the skip has stopped in the down position, the process of loading the weigh hopper starts. The weight hopper is installed on four weight sensors (positions 18-21 in pic. 1). Its bottom is equipped with an opening sensor and a closing sensor (items 16 and 17 in pic. 1). The control system checks the closing of the bottom (gives the command to close) of the weighing bin. If it is closed, the material feeder is turned on. The weight of the material in the weighing hopper is continuously analyzed by the dosing controller, and when the set dose is reached, the feeder is switched off. Material consumption and the number of loading cycles are not recorded.

7. After the dose of material has been collected, a command is given to open the bottom of the weighing hopper. After the bottom is completely opened (controlled by an opening sensor), the time for unloading the weigh hopper into the skip is counted and a command to close the bottom is given.

8. After the skip is loaded, the control system waits for a command to be received from the material level sensor in the furnace.

9. When a signal is received from the level sensor, the “skip up” command is given, after which the skip begins to move upward.

10. Then the cycle is repeated from step 1.

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