Cement, Energy and Environment

Al O , CaO, and Fe O ). The solid 2 3 2 3 remains from incinera on such as bo om ash, fly ash and scrubber sludge are landfilled. The total incinera on capacity for the incinerators in Ankleshwar, which is closest to Vapi, is approximately 7.5 tonnes per hour. The es mated genera on of sludge and plas c wastes from Vapi far exceeds the capacity of incinera on at Ankleshwar. Therefore, it is assumed that Vapi needs to install a new incinerator, close to the CETP, in order to u lize the mix of CETP sludge and plas c wastes. If installed close to CETP, the heat from the incinerator can be used in the MEE (inside the CETP) for driving away moisture from landfill leachate and other high COD containing industrial wastewater. Considering the case that the hazardous waste incinera on facility is installed in Vapi close to the CETP, the transport has been modelled taking 10 km distance. Ecoinvent processes have been used to model hazardous waste incinerator infrastructure (Ecoinvent centre, 2007). The emissions have been modelled using the auxiliary materials for flue gas treatment and the transfer coefficients in according to Doka (2003). As emissions are calculated from elemental waste composi ons it is necessary to assign chemical substances to certain types of air and water emissions. Co-processing in Cement Kilns Un l October 2016, the cement plants in Gujarat had co- processed 9.7 Mt of wastes; including 5.3 Mt of fly ash, 2.1 Mt of other alterna ve raw materials, 1.8 Mt of pet coke and 0.5 Mt of other alterna ve fuels. The major alterna ve raw materials u lised are synthe c gypsum, copper slag, iron sludge etc. The major alterna ve fuels u lised are plas c waste, biomass, process wastes, tyre chips, TDI tar etc. GPCB aspires to achieve 10% TSR before 2020. While evalua ng the co- processing scenarios, Ultratech Kovaya and the Ambujanagar plants, located 601 km and 714 km north of Vapi, respec vely, are chosen for energy and material recovery of CETP sludge. These plants have invested for developing pre-processing and co-processing facili es with adequate environmental, health and safety considera ons. In the modelled scenario for co- processing in cement kilns, sludge replaces fuel oil and coal usage since sludge combus on produces heat for the cement produc on process. The following ra o 60% coal and 40% petroleum coke has been used for the energy mix in the cement factory. The emissions to air have been modeled using transfer coefficients from Vermeulen et al. (2009 and 2012)). For all drying scenarios, corresponding transports and energy inputs and outputs have been adjusted. The infrastructure to be allocated to the co-processing of sludge is considered negligible as the main func on of the cement plant is to produce cement. The addi onal infrastructure to process sludge is considered minor and not included in this study. Results and discussions Results obtained with the CML2 method In this sec on the different scenarios for the management of the CETP sludge are compared with respect to environmental impacts. In order to be er compare the different scenarios, the environmental impacts have been calculated for 1 tonne of sludge with 10% moisture. In order to be er compare the different scenarios, the most relevant impact categories are selected, namely Abio c deple on (Use of resources e.g. minerals and fossil fuels), Eutrophica on (nitrogen and phosphorus), Global warming (greenhouse gases emissions 61