Monitoring and Control of Cooler Tank Level Measurement In Gas Cleaning Plant (GCP)

Abstract

The Cooler Tank Level plays a major role in Gas Cleaning Plants (GCP) and it is a very important parameter to be measured and controlled. If the tank level is not maintained in nominal range, the dust particles will accumulate on the Cooler Tank and affect the process. The production of copper metal at Vedanta, Thoothukudi include Blending of various grades of copper concentrates, Smelting and Refining. Sulphur dioxide is generated from during the smelting of copper and is converted to Sulphuric acid as a byproduct. This process involves three steps such as cleaning of sulphur dioxide gas from Furnace, Catalytic conversion of S02 to SO3 and amalgamation of SO3 with sulphuric acid. The conversion process is exothermic, reversible and adiabatic reaction and hence if the temperature increases it destroys the formation of sulphur trioxide. Hence in order to achieve high conversion efficiency, the converter gases need to be cooled. The SO2 gas from smelter contains metallic dust, fume, acid mist, water vapour and other impurities like halides which will contaminate the product. Therefore the gases are to be cooled and cleaned in Gas Cleaning Plant (GCP). Cooler tank used to remove water vapour from the gas and dust settle at the bottom of cooler. Cooler tank level needs to be maintained in order to avoid overflow of water into scrubber which will block the inlet gas. The level of cooler tank is to be continuously monitored and controlled to achieve the optimum results. The limitations of using Differential Pressure Transmitter for level measurement are overcome by ultrasonic based level sensor and automated using Distributed Control System and Human Machine Interface (HMI).