Initiatives in India |
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India is 2nd largest producer of cement in the world. Hence, cement industry in India is being engaged in continuous improvement in search of competitive edge over environmental concerns (a) ecological degradation at mines sites (b) air pollution due to both fugitive and stack dust emissions and (c) green house gases. Environment and energy are two important areas to be concentrated. Energy shares are almost nearly 45 % of production cost of cement and hence it is necessary to reduce costs, which improves environmental quality. CO2 emission per ton of cement produced varies from 0.975 to 1.192 over the period 1995-96 to 2001-02. This change in CO2 emission factor can be attributed to the following reasons :
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Variation in clinker -cement ratio i.e. increasing additive-cement ratio. |
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Variation in coal consumption i.e. coal/clinker ratio because of imported coal is preferred by many plants. |
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Shifting to a more energy efficient process (VRM, high efficiency cooler, fuzzy logic /expert kilncontrol system) |
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Improvement in energy (thermal and electrical) efficiency during cement production (better operational control and scale of production and blended cements). |
The initiative taken by NCB in "Life Cycle Analysis" (LCA) is environmental management tool and is new to Indian cement industry. (LCA is defined as "compilation and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout its life cycle). So far, LCA study has been carried out in steel, coal, waste paper and packaging sector. In developed countries like Europe, Australia, Canada and Japan LCA tools have continued to grow and mature meeting the greater demands for more environmental friendly manufacturing units/products. So, the relevance and value of LCA study for cement sector in India may be helpful.
Sustainability initiatives taken by some of the larger plants are:
a. Installation of captive thermal power plant based on lignite and pet coke
b. Usage of 100 % pet coke in cement kilns
c. Use of non conventional fuels
d. Attempts to use fly ash generated from their own captive thermal power plants
e. Installation of vertical roller mill/roller press and V-separator
f. Installation of mill optimizer packages for raw mill and cement mill
g. Retrofitting of coolers with CFG/IKN/Omega plates
h. Installation of Pyro Top in kiln for enhancing the clinker production
i. Installation of automatic process control system
j. Installation of variable voltage variable frequency (VVVF) drive for process fans.
k. Conversion of high pressure pre heater cyclones into low pressure
l. Close circuiting of cement and coal mills
m. Laboratory automation
n. Installation of multi channel burners
o. Installation of refractory bricks management system
p. Up gradation of kiln drives for enhancing kiln speed
Sustainability initiatives yet to get momentum/to be looked into:
1. Waste heat recovery system
2. Revival of sick plants to produce special cements with smaller volumes
3. Modelling of pyro processing for optimizing combustion in kiln
4. Feeding of kilns from both the sides
5. Oxygen enriched combustion (to kiln flame)
6. Installation of tumbler lining in calcining zone
7. Activation of fly ash (for higher dosage of fly ash addition) for producing PPC
8. Focus on optimization of particle size distribution of raw meal, coal meal and cements
9. High volume fly ash concrete
10. Using shotcreting route for refractory lining of kilns.
Conclusion
Achieving balance between economic prosperity, environmental quality and social progress is very important for sustainable development. Also, integrating natural resources and energy (these two are main drivers responsible for economic prosperity) are prime factors for sustainable development. Equally important is the issue of environmental quality to be addressed immediately.
From civil engineering point of view the construction quality methodology adopted and the materials used should lead to very durable, long lasting structures, which should have least harmful effects on the environment and should serve or fulfill the basic purpose for which structure is built, not only for current but also for future generations.
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