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Abstract:
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Cement industry ranks 2nd in energy consumption among the industries
in India. It is one of the major emitter of CO2, due to combustion of fossil fuel
and calcination process. As the huge amount of CO2 emissions cause severe
environment problems, the efficient and effective utilization of energy is a
major concern in Indian cement industry. The main objective of the research
work is to assess the energy cosumption and energy conservation of the Indian
cement industry and to predict future trends in cement production and
reduction of CO2 emissions. In order to achieve this objective, a detailed
energy and exergy analysis of a typical cement plant in Kerala was carried out.
The data on fuel usage, electricity consumption, amount of clinker and cement
production were also collected from a few selected cement industries in India
for the period 2001 - 2010 and the CO2 emissions were estimated. A complete
decomposition method was used for the analysis of change in CO2 emissions
during the period 2001 - 2010 by categorising the cement industries according
to the specific thermal energy consumption. A basic forecasting model for the
cement production trend was developed by using the system dynamic approach
and the model was validated with the data collected from the selected cement
industries. The cement production and CO2 emissions from the industries were
also predicted with the base year as 2010. The sensitivity analysis of the
forecasting model was conducted and found satisfactory. The model was then
modified for the total cement production in India to predict the cement
production and CO2 emissions for the next 21 years under three different
scenarios. The parmeters that influence CO2 emissions like population and
GDP growth rate, demand of cement and its production, clinker consumption
and energy utilization are incorporated in these scenarios. The existing growth
rate of the population and cement production in the year 2010 were used in the
baseline scenario. In the scenario-1 (S1) the growth rate of population was
assumed to be gradually decreasing and finally reach zero by the year 2030,
while in scenario-2 (S2) a faster decline in the growth rate was assumed such
that zero growth rate is achieved in the year 2020. The mitigation strategiesfor the reduction of CO2 emissions from the cement production were identified
and analyzed in the energy management scenarioThe energy and exergy analysis of the raw mill of the cement plant revealed
that the exergy utilization was worse than energy utilization. The energy analysis
of the kiln system showed that around 38% of heat energy is wasted through
exhaust gases of the preheater and cooler of the kiln sysetm. This could be
recovered by the waste heat recovery system. A secondary insulation shell was
also recommended for the kiln in the plant in order to prevent heat loss and
enhance the efficiency of the plant. The decomposition analysis of the change in
CO2 emissions during 2001- 2010 showed that the activity effect was the main
factor for CO2 emissions for the cement industries since it is directly dependent on
economic growth of the country. The forecasting model showed that 15.22% and
29.44% of CO2 emissions reduction can be achieved by the year 2030 in scenario-
(S1) and scenario-2 (S2) respectively. In analysing the energy management
scenario, it was assumed that 25% of electrical energy supply to the cement plants
is replaced by renewable energy. The analysis revealed that the recovery of waste
heat and the use of renewable energy could lead to decline in CO2 emissions 7.1%
for baseline scenario, 10.9 % in scenario-1 (S1) and 11.16% in scenario-2 (S2) in
2030. The combined scenario considering population stabilization by the year
2020, 25% of contribution from renewable energy sources of the cement industry
and 38% thermal energy from the waste heat streams shows that CO2 emissions
from Indian cement industry could be reduced by nearly 37% in the year 2030.
This would reduce a substantial level of greenhouse gas load to the environment.
The cement industry will remain one of the critical sectors for India to meet
its CO2 emissions reduction target. India’s cement production will continue to
grow in the near future due to its GDP growth. The control of population,
improvement in plant efficiency and use of renewable energy are the important
options for the mitigation of CO2 emissions from Indian cement industries |