Waste Heat Recovery System at Durg

Process

The waste gas when passed through a heat recovery steam generator made of radiant/conducive heat transfer surfaces, can generate steam qty. equivalent to about 11.8 TPH from each kiln depending on the kiln gas flow and temperature combinations.

In the FBC boiler air or gas is passed through an inert bed of solid particles with high velocity.The air bubles through the bed and particles attain state of high turbulence. The bed assumes the appearance of a fluid and is then heated to ignition temperature of fuel.

The fuel burns rapidly and the bed attains a uniform temperature due to effective mixing. The temperature of fuel should never be allowed to approach ash fusion temperature due to effective mixing. The temperature of fuel should never be allowed to approach ash fusion temperature to avoid melting of ash. This is achieved by conductive and convective heat transfer through tubes immersed in the bed. The Steam from WHRSG and FBC is brought to turbine through ESV .

Turbine Control & Protection (Automatic)

Latest state of the art Microprocessor based fault tolerant systeminstalled for controlling the operation and safety of the turbine.
Triple Modular Redundant (TMR) PLC system of Triconex Corporation USA helps in monitoring and controlling important process parameters.
During critical process condition, turbine control is taken over by Automation till process is normalised
Human machine interface and the data acquisition are through the SCADA system.
System is having 100 milliseconds cycle time.
Power is supplied to the automation system through a dual redundant UPS system

Generator Control & Protection

Generator excitation is controlled by a micro processor based ultra fast IGBT powered AVR within cycle time of 400 milliseconds supplied by M/S CKD Czech Republic.
Generator protection is achieved by multi functional microprocessor based programmable relays of Siemens, Germany.

Boiler Control & Protection

Controllers and the hot redundant PLC system of Simens are installed for automatic drum level control and combustion control of the FBC.