Use of alternate fuels in the Cement Kiln leads to excessive preheater exit temperatures. The Cement plant in Jakarta, Indonesia with a capacity of 7800 TPD, planned extensive use of alternate fuels in the kiln. This was leading to excessive Preheater exit temperatures up to 4300C and was limiting the fan capacity. Hence, they needed a gas cooling system before the fan to reduce the temperature by 500C so that the plant production level is maintained/enhanced as required.
The Plant project team looked at the possibility of gas cooling system in the down comer, however it was not feasible as the duct had many bends/limited straight lengths. These can lead to operational complications due to coating formations in the duct walls and fan impellers. Their Vendor NASEQUIP Systems, well known manufacturer of gas cooling systems suggested to install a single fluid, high pressure gas cooling system in the Top cyclones of the plant. These systems operate with Single fluid, high Performance lances with flow control effected by VFD driven Pump. It also improves Cyclone collection efficiency.
The plant has 2 Preheater strings each having twin Cyclones. NASEQUIP designed the system with 4 lances in each cyclone. Each Preheater string was fed by a high-pressure pumping unit independently controlled by varying the speed of the Booster pump.
High performance lances with auto-drain facility
Pneumatic Cylinder for Drain valve operation
The gas cooling is done in the Preheater top cyclone by means of high-pressure nozzles installed from the sidewalls. For better rangeability and droplet control, the Plant opted operation of system from 30 to 50 bar pressure @ nozzle. For these 2 multistage pumps - feed & booster pumps - were used in series. The nozzles are located about 800 mm directly below the dip tube periphery. The nozzles spray is directed 45 Deg. downwards from the lance axis.
Lances mounted on the cyclone wall
High pressure pump station consisting of self-cleaning suction filter, multistage horizontal type feed pump with motor, vertical booster pump operating with VFD etc. is located in the first floor. The water tank was located at second floor. The final outlet pressure at the booster pump outlet was ranging between 38 bar to 55 bar.