Estimation of the Coke Calcination Yield by Granulometry Analysis

At Rio Tinto operated calciners, the masses of the green petroleum cokePetroleum coke (GPC) feed and of the produced calcined petroleum cokePetroleum coke (CPC) are continuously measured by belt scales. In spite of frequent calibration, CPC yieldsYield based on the measured mass flows are not always accurate. Thus, CPC yieldsYield are calculated from GPC deliveries, CPC shipments, and inventory changes. This approach only allows calculating CPC yieldsYield over long periods. An alternative methodMethod was therefore developed. During calcinationCalcination, GPC loses humidity and volatiles. CokeCoke fines are entrained by the gas flow and swept out of the kilnKiln or oxidised. The quantity of lost fines can be determined by GPC and CPC granulometryGranulometry analysis. The CPC yieldYield is calculated from the combined mass losses. Calculated yieldsYield agree well with values determined by the long-term mass balances. Furthermore, short-term yieldYield changes can be detected.