Решение АСУ ТП на примере ОАО «Маркохим» коксовой батареи №3
A three-phase asynchronous motor starts the electric drive of the suction fan that ensures emission-free coke pushing into the coke oven. Prior to the restoration, the fan drive operated off the electric supply line. Acceleration used to start with motor winding connected in wye (40 seconds) which later switched to delta (5-7 seconds up to the nominal speed. Across-the line start of the motor happened in 40-50 seconds. The fan motor works uninterruptedly. When loaded, the electric drive works for 1 minute. The coke oven door opens and the coke is pushed. Then the motor runs idle for 9-11 minutes while the door is closed.
PROCESSES AUTOMATION PURPOSES
The electric drive puts into motion the fans of the emission-free coke pushing. It also serves the following purposes:
- smooth acceleration at a fixed pace and with fixed values of the stall current;
- adjustable rotation speed;
- alarm system, displaying all the parameters and operational modes on the screen;
- safety protection in emergencies;
- energy consumption monitoring
- control over the emission-free coke pushing under the automatic operational mode.
PROCESSES AUTOMATION STRUCTURE
The electric drive runs the suction fans that ensure cyclic dust-free coke pushing. Only one fan can be powered from the frequency converter at a time. The electric drive is well adapted to working in highly polluted environments.
The fan drive is powered by a Siemens frequency converter. The power circuit of the converter includes the following elements: disconnector with fuses, сommutating inductor, rectifier unit with an inverter, power supply unit for local needs. All the equipment is located in waterproof cabinets rated IP 54. The cabinets also contain a refrigerating unit and an embedded heater. The cabinet door has an optional input/output panel for adjusting the parameters of the converter.
The suction fans are powered by the mains or by the frequency converters. They are switched on and off with the help of the same push-button stations located next to the mechanisms.
PROCESSES AUTOMATION FUNCTIONS
Frequency converters ensure safety in the following situations:
- engine overload;
- frequency converter current overload;
- frequency converter overheating (when the cooling air is hotter than required);
- voltage reduction (the converter switches off when the system voltage drops to 20%);
- overload in DC link (in the process of deceleration, the converter switches off in case of overload);
- phase loss;
- short-term power loss
- Better performance
- Lower energy consumption
- Automatic operation
- Higher reliability of the system
- Control over the necessary parameters of the engine
- Efficient troubleshooting
- Easy access to any information about the electric drive performance