technology, energy efficiency and environmental externalities in the ...

40 Technology, Energy Efficiency and Environmental Externalities of the Cement Industry
there has been a slowdown in the growth of small mills at the cost of medium and largesize
plants.
% of Total Production
90
80
70
60
50
40
30
20
10
0
1970 1980 1985 1986 1987 1988 1989 1990 1991
Figure 5.5. Share of small mills in Chinese cement production
In India, the small units in private sector and large mills in public sector have been growing
in parallel. The shares of private sector and public sector in total cement production are
given in Table 5.1.
Table 5.1. Shares of private and public sectors in India (% of total production)
1977 1983 1991 1992
Private Sector 90.08 83.90 89.80 89.60
Public Sector 9.92 16.10 10.20 10.40
5.3 Characteristics of the Parameters affecting Energy Efficiency
The major parameters which affect the specific energy consumption of the cement industry
are:
- Control on raw material mixing
- Process mix (dry, wet, semi)
- Degree of precalcination
- Level of waste heat recovery
- Product mix, etc.
The specific energy consumption of the cement industries in selected countries are shown
in Figure 5.6.
It can be seen that the specific energy consumption of Chinese cement industry is nearly
twice as much that of former west Germany. The trends of specific energy consumption in
selected countries are shown in Figure 5.7.