HOW IT WORKS : Coke calcining plants can be located in oil refineries, captive plants in aluminum smelters or merchant plants.
ROTARY KILN : The petroleum green coke is fed into a refractory lined rotary kiln where the volatiles are driven off during the calcining process in an oxygen deficient atmosphere. Air can be injected through the kiln shell to burn a portion of the volatile matter in the kiln providing usable heat to the kiln.
COOLING : Once the calcined coke is discharged from the kiln, the coke is cooled in a rotary cooler. At the feed end of the cooler, water is sprayed on the calcined coke to cool the coke to acceptable temperatures. The water evaporated in the process.
AFTERBURNER : The kiln exhaust gas is oxygen deficient and contains volatile matter released in the kiln. The kiln exhaust gas is directed to an afterburner (secondary combustion chamber) and air is injected to burn the volatiles and dust. A waste heat recovery boiler is used to produce steam from the heat contained in the afterburner exhaust gas.
FLEXIBILITY IN OPERATIONS : Metso rotary kilns can handle a wide range of green coke feeds including needle, sponge, shot, fluid or tar pitch green cokes. The rotary kiln is also able to optimize the coke calcining operating parameters, be it residence time, temperature gradient, and heat up rate, all of which impact product quality. Coke kilns can be fueled with: gas, heavy oil, oil, refinery gas, waste oil and solid fuel, fired independently or in combination.