Cement Energy Environment

60 • A typical view (Figure 5) of hot air circulation at cooler is shown as below Figure: KHD Pyrostep Cooler with hot air circulation and Intermediate crusher The implementation of carbon capture, use, and storage in the cement industry is a necessity, not an option, if the climate targets are to be met.Although no capture technology has reached commercial scale demonstra- tion in the cement sector yet, much progress has been made in the last decade. Further if all together technol- ogy available at various recent developments like KHD supplied Plant where usage of Alternate raw materials, Usage of AFR in Pyrorotor and cogeneration system along with least power consumption machines like Roll- er Press and low Pressure drop preheater system are Future Ahead Waste Heat Recovery system utilisation to generate electricity from waste gases is emerged as prominent requirement in cement Industry not only to survive is cost reduction of electricity but also to reduce CO 2 footprint remarkably. During last decade it was matter of debate whether Cogeneration is efficient way of power generation but after successful implementation of such projects similar to China it is made mandatory in India as well to setup Co-generation plant along with Clinkerisation plant for upcoming projects. On average cogeneration can generate electricity 30-35 Kwh/t clinker whereas the consumption of electricity stands as 45-50 kwh/t clinker .Each kwh of electricity is equivalent to nearly 1.02 kg CO 2 emission hence saving of 30 kwh/t cement will add to saving of approx. 67650 mt CO 2 per annum.(considering 6700 tpd clinker production 1.02 kg CO 2 /Kwh electricity). Cogeneration is made an important cost saver and this concept is very much adopted by leading cement manufacturers in India, for this purpose machinery selection is being made with Roller Press as grinding machine where lower hot gas temperature after boiler can be accepted in range of 150-160 Deg.C for normal moisture in Raw material and simultaneously saving of grinding power consumption by 3-4 Kwh/t clinker. Introduction of cooler equipped with hot air circulation and Intermediate clinker crusher at Cooler mid-air zone increased further potential of cogeneration by 500 Kwh to 800 Kwh for 1.5-2 MTPA kiln lines. Recent examples of such hot air circulation is very much popular in India like Shree cement Pyro lines and Chettinad cement new Project commissioned under supply of KHD Humboldt Wedag recently. Thermal Energy Efficiency used then the total saving of CO 2 can be best worked out around 388-390 kg CO 2 /t cl (158 kg from RDF/ AFR+200 kg from Alternate raw material (30% usage of slag )+30-32 kg from WHRS), hence it is remarkable saving in CO 2 which is about 40% of total CO 2 pro- duced by clinker production( 950 kg/t clinker), now if Clinker factor is reduced to 35% like in case of Portland Slag Cement where clinker factor is only 35% then the total CO 2 count stands 235 only ( 950-390=560, 35% equal to 196+40 (for Grinding power) hence total 236 kg/t cement is possible.