SCADA-based control system of pilot plant for chemical leaching of high ash Indian coals

The chemical leaching process of coal opens up many opportunities as it can produce very low ash coal without deteriorating the yield and product quality. In this context, as the chemical leaching process is influenced by many factors such as mineralogy of feed coal, reaction temperature, reagent concentration, solid-to-liquid ratio and reaction time, etc., the maximum ash reduction with minimum operating cost is not practically possible without the assistance of efficient control system. In this paper, the various steps involved in the design and development of the SCADA-based control for chemical leaching process has been discussed. The control system implemented at pilot plant with the production capacity of 500 kg coal per batch is strong and efficient in regulating the process parameters, operating the plant and acquiring the valuable data for further scale-up. The ROCKWELL-based Control-Logix PLC and the state-of-art instruments have been used to accomplish the task.