Cement Energy and Environment

scope of investment for modernisation for fuel economy. These parameters are amply revealed in any comparative study among plants within a country. A few more country -specific parameters play a significant role in the comparison of plants in different countries. For ease of comparison, 6 Southeast Asian plants and 3 Indian plants, nearly comparable in capacity and energy performance, have been reviewed here. The names of the plants are not mentioned to avoid any undue bias, but denoted just by numbers under each country. The parameters studied are : age of the plant and the present status of its plant and machinery, section-wise energy consumption, process and operational parameters affecting energy consumption , and any other factor(s) having an impact on energy consumption. Tables I and 2 summarise these parameters for easier comprehension. 3. Technology Level and Operational Parameters a) Age and lnstdlled c.1pacity of the plant The Southeast Asian plants were originally set up in the fifties, sixties and seventies, except one plant (No. 5) which was started in the mid forties. The original capacities of some of these plants had been fairly larger ( 1950 tpd in 1955 for plant 3; 3250 tpd in 1975 for plant 1) than their Indian contemporaries at that time. They had also undergone rapid expansio n and modernisation in the eighties and nineties, and at present are of much larger capacities than contemporary Indian plants. Plants 1, 2 and 3 are 4 million- tonne-per-annum (MTPA) and above, plant 4 is 7-MTPA and plant 6 is 6-MTPA. In comparison , the th ree Indian plants set up in the eighties and nineties are of much lower capacity (2 to 4-MTPA); p lant 8 is a very old one set up in the fifties but completely modernised in the nineties. b) upaclty utilisation The production figures for 1998 and the relative capacity utilisation show the same trend in all the plants. It ranges from 6 5 to 75 per cent for the Southeast Asian plants, due primarily to demand recession. For Indian plants it varies widely - from 55 4 to more than I 00 per cent. Higher capacity utilisation has a definite positive impact on energy conservation for the Indian plants. However, higher individual plant capacity. coupled w ith modern energy conservation measures, eg, waste-heat-recovery based power generation and use of waste derived fuels (WDF) had helped plants in Taiwan and South Korea to achieve significant energy conservation. c) Technology adoption level In spite of introducing latest generation large capacity kilns for capacity enhancement, the level of technology adoption in supporting departments (raw meal grinding, cement grinding) vary widely from plant to plant and hybrid technologies are common in most plants. There are several reasons for such hybrid mix, which are specific to each case. Presumably, the urge for higher production through larger capacity ki lns did not chronologically find a matching support in improved comminution technologies. Historically, vertical roller mills (VRM's) and roll presses are much later advents than multi-million capacity kilns. And, even among the different grinding technologies advanced during the last decade, the comparative advantage of one or the other brand or type remains a matter of debate. Obviously , many cement manufacturers preferred to continue with the traditional and proven technology in a recessionary market than to try a new one w ith unsure promise. The level of technology in major unit operations, process and operational indicators and energy consumption pattern for the 9 plants can be summed up as follows : i. Mining- All plants follow the conventional mining practice by drilling and blasting. Surface miners (for mineral and energy conservation) or rippers (on environmental considerations) are yet to find common acceptance. The only noticeable change is adoption of larger capacity mining, loading and haulage machinery to match the higher production capacity. ii. Transport of mined material - Both for energy conservation and larger output, all the p lants substituted truck transport by belt conveyor or