Reliable Steam Generation in Coal-Fired Power Stations

In a coal-fired power station, the steam required to drive the turbines is generated by burning pulverized coal. The energy released during this process heats a boiler with integrated piping. The water that is fed into this boiler is then converted into steam. To ensure reliable and efficient operation, it is necessary to monitor the injection of pulverized coal into the burner with a defined air quantity, as well as the superheater, the preheating unit for the feed water, and the combustion air. This requires the signals to be transmitted reliably between the plant and the control room.

Monitoring the pulverized coal in terms of quantity and pressure ensures that the plant operates in an optimum temperature range and that, to a certain extent, it is possible to match loads. The pipes in the superheater banks and the preheating unit for the feed water and air are monitored with regard to temperature, flow, and/or pressure to ensure the optimum process parameters are maintained. In addition, deposits on the surface of the boiler and pipe interior are detected early, preventing increased energy requirements and thermal stresses in the metal.

The interface modules of the K-System, which features galvanic isolation and delivers functional safety up to SIL3, transmit signals between individual system components and the control room without any interference. The product range includes both isolated barriers for intrinsically safe applications, to protect the hazardous area against an excessively high energy input, as well as signal conditioners for nonhazardous areas. The interface modules control the pressure and quantity of pulverized coal that is supplied and monitor the temperature, flow, and pressure of the superheater, burner, and feed water.

Using transmitter supply devices to monitor the pressure and flow is not only relevant for supplying pulverized coal to the burner; measurement data from the superheater and preheater for the feed water and combustion air are also transmitted to the control room reliably and without any interference. Temperature converters with trip values are used to measure impermissibly high or low temperatures. They protect against the effects of deposits in pipes and damage to turbine blades caused by water droplets, and enable an optimum efficiency factor.

• Transmitter supply devices provide pressure and flow monitoring of the burner supply, superheater, feed water, and combustion air.
• Temperature converters with trip values for thermocouples, potentiometers, and resistance thermometers monitor the temperatures of the key components in the burner and boiler.