Cement, Energy and Environment

Limestone suitable for FGDs are defined in FGD specifica on documents of Central Electricity Authority (CEA). It is to be noted that the quality requirements are similar to the Limestone Quality requirement for Clinker Produc on. Higher the Lime content in Limestone, the purity of Synthe c Gypsum Produced by FGDs will be be er. Typically, the Limestone requirement for FGD plant with Sulfur content of 0.5-0.7 percent in coal fired in power plants is about 0.23-0.30 TPD of Limestone/MW installed Capacity. It is es mated that, the Limestone demand by FGD systems will be about 15 million tons per annum (MTPA) by year 2022. Synthe c Gypsum (SG) FGD Plants of Wet process Technology generate a solid product, which has similar chemical composi on of Gypsum i.e. CaSO4.2H20. This product, in the form of Slurry is collected at the bo om of the SOx absorp on tower. The slurry passes through Belt filters to generate Filter cake of about 10-12 percent moisture. This cake is stored in open spaces for sun drying and also for loading into trucks/wagons. The expected quality of Synthe c Gypsum from Wet FGDs is as follows Gypsum Purity (as CaSO4.2H20, dry) –> 80-90 percent (depends on LS quality) Free moisture: 10-12percent Par cle size : 100 percent passing 200 Microns. Though above parameters are similar to Phospho-gypsum, Synthe c Gypsum is not having phosphoric compounds and hence the se ng mes achieved with usage of Synthe c Gypsum is as good as that for Mineral gypsum. Gypsum Availability for Cement Industry At present, in India, out of about 13.5 Million Tons of gypsum (all types) consumed, 99% of gypsum is used by cement industry. Due to shortage of gypsum produc on in India, about 4.0 million tons of mineral gypsum is imported over last few years from countries like Oman, Pakistan& UAE. 2013-14 2014-15 2015-16 Total Consump on 9.22 9.75 10.31 - In Cement 9.16 9.70 10.24 Mineral Gypsum 5.39 5.67 6.02 - In Cement 5.35 5.64 5.96 - In POP (Plaster of Paris) 0.038 0.137 0.157 By Product Gypsum 3.28 3.58 3.8 - In Cement 3.28 3.58 3.8 Marine Gypsum 0.534 0.481 0.482 - In Cement 0.534 0.481 0.482 Gypsum Consump on Pa ern (in million tonnes) 50