Cement, Energy and Environment

. -f ' ~ • ' 1000 An . . Increase In 995 3000 t/d 6000 t/d 9000 t/d 12 000 t/d ~ the electrical power generated from a mid-air tapped I r- I I I r- I I '-- I - ' .. r- ,.... .... f-- ' - WHRS on a cooler ~ u 0 wi th - QJ .... recirculation not only ::J - ru from .... benefits a QJ c. higher output for E QJ - power generat ion. .... ·- ru When operating the > .... ru cooler in recirculation -c r:: 0 mode, the secondary v QJ "' a1r temperature can 990 985 980 975 970 be enhanced. On f-- - I I • average, an about 25 oc higher secondary 965 . temperature a1r can 960 be observed with recirculation (Fig. 6). This roughly equals to a 7 kcal/kg clinker energy reduction. Fig. 6 Secondary air temperatures as a function of production Converted into fuel savings this is equivalent to more than US$ 135 000 pa (heating value 28.5 MJ/kg, US$100/t). Conclusion Recirculation is a proven approach to boost the performance and to increase the output of a WHR solution within the cement plant. It also helps to eliminate an existing or to avoid an add itional emission point. Further savings can be realized through the increased secondary/tertiary air temperatures . In the case of recirculation, increased power consumption is more than compensated by the higher amount of energy in the mid-air duct. However, a higher recirculation air temperature has to be taken into account for this approach. A Pendulum Cooler®is highly suited to cope with that challenge, since constructions allows for higher its general recirculation temperatures. Furthermore, it does not have any temperature sensitive parts under the grate. A tailor-made design of the cooler offers manifold variants involving mid-ai r and vent-air tapping depending on the individual requirements or priorities of a plant. At present a recirculation system associated with an IKN cooler is under commission at J.K. Lakshmi Cement, which operates three lines with IKN coolers. References [1] Thomas Weiss, Reinhard Koehler, John Carli ll. Reaping the rewards of recirculation. World Cement 4/2014 , pp. 107-113. *~:*** 15