Observer-based fault-tolerant sliding mode controller for controlling temperature of zinc oxide rotary kiln to reduce carbon emissions

Abstract The zinc oxide rotary kiln in the zinc smelter industry is the primary source of carbon emissions, causing an imbalance between zinc recovery and emissions. To speed up zinc restoration, large fuel amounts are used which increases carbon dioxide emissions. Due to the kiln’s sensitivity to hydrometallurgical factors and external inconsistencies, it is very challenging to keep the temperature variation in control at the reaction zone and rotating tail within the specified ranges, particularly when using standard controllers which affect the states of the system with miscellaneous faults that leads to failure of total plant. To overcome this a controller using Cubature Kalman Filter (CKF) has been designed where Fault-Tolerant Sliding Mode Controller (FTSMC) and Observer are working combinedly. FTSMC is applied in industrial process control system for controlling sensor and actuator faults at high temperature. To measure other internal faults, parameters, and measurable states, a Fault-Tolerant Observer (FTO) is needed integrating with robust controllers for real time fault estimation and control. The control approach using total variation and mean square deviation was tested on an industrial Zn rotary kiln and compared to a traditional sliding mode control scheme.