GHG REDUCTION POTENTIALS IN THE INDIAN CEMENT
INDUSTRY – UPSCALING IMPLEMENTATION
*P Fonta, *E Sar, **PV Kiran Ananth, ***SK Chaturvedi, A Pahuja***, R Bhargava****, KN
Rao*****, L ^Rajasekar, ^SV Herwadkar, ^^S Shrivastava, ^^^S Krishnamoorthy
*World Business Council for Sustainable Development, Geneva, Switzerland
** Confederation of Indian Industry, CII – Godrej Green Business Centre, Hyderabad, India
***National Council for Cement and Building Materials, Delhi, India
****Shree Cement Limited
*****ACC Limited
^UltraTech Limited
^^Ambuja Cements Limited
^^^International Finance Corporation (IFC)
ABSTRACT
Global Cement Technology Roadmap was developed in 2009 through a partnership between the CSI
and the International Energy Agency (IEA). A country specific adaptation was required to better address
the local issues and develop targeted actions to contain the CO2 emissions. CSI members in India
collaborated with IEA in early 2013 to develop Low-Carbon Technology Roadmap for the Indian
Cement Industry. The initiative was supported by the International Finance Corporation (IFC), a
member of the World Bank Group.
The India roadmap outlines a low-carbon growth pathway for the Indian cement industry that could
lead to carbon intensity reductions of 45% by 2050, from the 2010 level. It projects that these reductions
would come from increased clinker substitution and alternative fuel use; further improvements in
energy efficiency, and development and widespread implementation of newer technologies.
The project is now in the second phase where some of the CSI member companies in India have
commissioned studies to assess the potential and feasibility of implementing the technologies outlined
in the technical papers. The assessment will identify specific areas where investments related to energy
efficiency, technology up-gradation, material conservation, etc. can lead to greenhouse gas (GHG)
emissions reductions. Phase 2 studies are currently underway in four CSI India companies, and two
more have confirmed and are in initial stages.
This paper attempts to report the progress and outcomes of the Phase 2 studies.
1.0
Introduction
The Indian cement industry is the second largest producer in the world, comprising 183 large cement
plants and 360 mini cement plants. The installed capacity and production during the year 2011-12 were
336 million tonnes and 247 million tonnes respectively. The average installed capacity per plant was
1.7 MTPA, compared to more than 2.1 MTPA in Japan. While the industry’s average energy
consumption is estimated to be about 725 kcal/kg clinker thermal energy and 80 kWh/t cement electrical
energy, the best thermal and electrical energy consumptions presently achieved are about 667 kcal/kg
clinker and 67 kWh/t cement respectively. These are comparable to the best reported figures of 660
kcal/kg clinker and 65 kWh/t cement in a developed country like Japan. In this context, CO2 emissions
which is one of the main Greenhouse gases (GHG), is generated from the decomposition of
carbonaceous raw materials in the cement kiln (50-55%), burning of fossil in cement kilns (40-45%) or
burning of fossil fuels in captive thermal power plant at cement plants (up to 10%).
The Indian cement industry’s efforts to reduce its carbon footprint by adopting the best available
technologies and environmental practices are reflected in the achievement of reducing total CO2
emissions to an industrial average of 0.719 tCO2/t cement in 2010 from a substantially higher level of
1.12 tCO2/t cement in 1996. In order to further reduce CO2 emissions, four key technology levers have
been identified which can contribute to reduction in CO2 emissions. These form the basis of a lowcarbon technology roadmap for the Indian cement industry which was launched in February 2013.
These levers include increased use of Alternative Fuels and Raw materials (AFR), improvement in
thermal and electrical energy efficiency, reduction in clinker to cement ratio, and application of newer
technologies in the manufacture of cement. In addition, recovery of waste heat for co-generation of
power can contribute further to emissions reductions at a plant level.
As part of phase 2 of the project, six of CSI member companies in India with part funding by IFCinitiated studies to assess the potential and feasibility of implementing the technologies outlined in the
technical papers. These Phase 2 studies have enabled CSI member companies in India to undertake a
resource efficiency assessment, looking into feasibility of implementation of these technologies at
identified manufacturing locations. The assessment is helping to identify specific areas where
investments related to energy efficiency enhancement, technology up-gradation, material conservation,
etc. can lead to greenhouse gas (GHG) emissions reductions.
2.0
Background: Low carbon technology roadmap
The International Energy Agency is leading the development of a series of energy technology roadmaps
which aim to accelerate the development and deployment of the major technologies needed to reach the
ambitious goal of limiting global temperature increases to 2 degrees Celsius. The IEA’s approach
involves engaging experts from industry, government and research institutes to work together with the
IEA in elaborating an implementable strategy to accelerate the development and deployment of a given
technology or realising the energy and emissions reduction potential of a given industry sector. The
roadmaps outline an action plan for specific stakeholders to show the short- and longer-term priorities
needed to achieve deep emissions reduction.
In 2009, recognizing the urgency of identifying technologies to enhance the reduction of the energy use
and CO2 intensity of cement production, CSI worked with the IEA to develop the first industry roadmap.
That roadmap outlines emissions reduction potential from all technologies that can be implemented in
the cement industry. Building on the success of the global cement roadmap, IEA and CSI, in
collaboration with CII and NCB joined together to develop a roadmap specifically for the Indian cement
industry.
3.0
Low carbon roadmap: Modelling and findings
The IEA Energy Technology Perspectives 2012 (ETP 2012) uses extensive modeling to examine
possible scenarios of global energy demand in the future. Its 2°C Scenario aims at limiting the increase
in global average temperature to 2°C and examines how to achieve deep emission cuts to at least halve
global emissions by 2050. The 6°C Scenario (6DS) serves as the baseline scenario which is largely an
extension of current trends, with no effort to curb emissions. Under the 2DS, annual global industrial
emissions would be 6.7 GtCO2 in 2050, about 20% less than current levels. For India, a detailed analysis
was performed in collaboration with the Indian experts. The analysis indicated that total industrial
emissions would reach between 0.8 GtCO2 and 1.1 GtCO2 in 2050.
This represents a direct emissions reduction1 of about 0.28 tCO2/ t cement produced – from 0.63 tCO2/t
cement in 2010 to 0.35 tCO2/t cement in 2050. Such a reduction in emission intensity would limit the
increase in CO2 emissions from the cement industry to just a doubling despite a four-fold increase in
production. The Indian cement roadmap uses the IEA model to identify a vision for the industry to
contribute towards significant energy and emissions reduction and helps to evaluate the technologies
needed to achieve this goal.
The key levers to reduce emissions in the Indian cement industry are increased use of alternative fuels,
increased thermal and electrical energy efficiency, increased rates of blended cement leading to a
1
Direct emissions from cement manufacturing process. Does not include indirect emissions from the production of
electricity.
reduction in clinker-to-cement ratio, a radical step change in new technology development to bring
potential technologies such as carbon capture and storage from research and development to
deployment and widespread implementation of waste heat recovery systems. The implementation of
these technologies could lead to energy savings of at least 275 PJ which is equivalent to the current
industrial energy consumption of Singapore or the Philippines.
4.0 Feasibility studies – Phase 2 of roadmap
As a logical next step in implementation of levers identified in the Roadmap and the Technology papers,
six CSI India member companies initiated feasibility studies at one of their plant to assess the potential
of reduction from these technologies. These assessments are helping to identify specific areas where
investments related to energy efficiency, technology up-gradation, material conservation, etc. can lead
to greenhouse gas (GHG) emissions reductions.
At the time of preparation of this paper, study results were available from four plants. Studies are
underway in another plant, and are due to be initiated in the sixth plant.
The next section attempts to summarise the results of the assessment for each technology area and
indicates the replication potentials.
4.1 Topic 1 - Electrical and thermal energy efficiency improvements in Kilns and preheaters
Background
The installation of high efficiency low pressure drop) cyclones offers significant energy efficiency
improvement opportunity in cement kilns. Installation of additional preheater stages for increased heat
recovery, reducing the pressure drop in preheater cyclones by conducting computational fluid dynamics
(CFD) studies and implementing the findings with necessary modifications, offer substantial electrical
and thermal energy efficiency improvement opportunities.
With several advancements in refractory properties, such as thermo-mechanical and alkali resistance,
cement kilns today can minimize the radiation losses as well as handle increased AFR substitution rates.
Automation and control systems, such as adaptive-predictive control systems and online control
systems for flame, free-lime, inlet NOx reduction are very effective for better throughput, smooth
operation and control.
Anticipated benefits of this paper:
• Thermal savings: 15 - 20 kcal/kg Clinker
• Electrical saving: 2 - 3 kWh/MT Clinker
• CO2 reduction potential: 7 - 10 kg CO2/MT Clinker
Current Status
The Indian cement industry has achieved very high levels of technology adoption and energy efficiency
levels. With significantly higher productivity levels and installation of latest energy efficiency and
automation control devices, these systems are operating at one of the best performance levels in the
world.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
Plant 1
Plant 2
Plant 3
Plant Capacity TPD Clinker
2800
2700
Kiln 1: 4300
Kiln 2: 4145
Kiln 3: 3585
Thermal savings possible (kCal/kg clinker)
3
10
17
Electrical savings possible (kW/MT Clinker)
0.47
3.1
0.35
Annual energy savings (Million INR)
4.5
22.9
27.8
Investment requirement (Million INR)
5
13.5
10.9
1573
6417
10170
CO2 reduction potential (MT CO2/Annum)
Replication potential:
Average
potential
2.1
0.75
Replication
potential
251
0.75
Thermal savings possible (kCal/kg clinker)
13.7
13.7
Electrical savings possible (kW/MT Clinker)
0.79
0.79
Annual energy savings (Million INR)
23.3
3248
Investment requirement (Million INR)
10.4
3248
Plant Capacity MTPA Cement
Average clinker factor
CO2 reduction potential ( MT CO2/Annum)
8218.8
CO2 reduction potential ( Million MT CO2/Annum)
1.19
4.2 Topic 2: Latest generation high efficiency clinker coolers
Background
Retrofitting of existing conventional reciprocating grate coolers with latest generation coolers offers a
significant potential for electrical and thermal energy saving. The secondary and tertiary air
temperatures offered by latest generation coolers have also increased to about 1250⁰C and 1000⁰C,
respectively and cooling air requirements have also gradually reduced to about 2.2 –2.4 kg/kg clinker.
The total heat loss of latest generation clinker coolers is less than 100 kcal/kg clinker, and recuperation
efficiency in the range of 75–80 %.
Anticipated benefits of this paper:
• Thermal savings: 10 - 30 kcal/kg Clinker
• Electrical saving: 0 - 1 kWh/MT Clinker
• CO2 reduction potential: 8 - 10 kg CO2/MT Clinker
Current Status
The Indian cement industry, over the last several years, had increasingly adopted reciprocating grate
coolers with great success. With more than 50 % of cement produced from kilns less than 10 years old,
reciprocating grate coolers have become common practice in the industry today. Conventional grate
coolers provide a recuperation efficiency of 50–65 %, depending on the mechanical condition and
process operation of the cooler. This corresponds to a total heat loss from the cooler of about 120–150
kcal/kg clinker. Based on the cooling efficiency, technology adopted, and desired clinker temperature,
the amount of air used in this cooling process is approximately 2.5 - 3 kg/kg of clinker.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
Plant 1
Plant 2
Plant 3
Plant Capacity TPD Clinker
2800
2700
4300
4145
Thermal savings possible (kCal/kg
30
55
55
55
clinker)
Electrical savings possible (kW/MT
Clinker)
Annual energy savings (Million INR)
28.6
49.2
206.2
Investment requirement (Million INR)
101.5
200
600
3585
43
-
CO2 reduction potential (MT
CO2/Annum)
11252
19892
82867
Replication potential
Average
potential
2.1
0.75
Replication
potential
150
0.75
Thermal savings possible (kCal/kg clinker)
48.5
30
Electrical savings possible (kW/MT Clinker)
0.00
0.00
Annual energy savings (Million INR)
153.7
3375
Investment requirement (Million INR)
458.8
34080
CO2 reduction potential ( MT CO2/Annum)
30380
1356264
Plant Capacity MTPA Cement
Average clinker factor
CO2 reduction potential ( Million MT CO2/Annum)
1.35
4.3 Topic 3: Energy efficiency in grinding systems
Background
For raw material grinding, the most commonly used grinding technology is Vertical Roller Mills
(VRM), while few older facilities still operate with either ball mills alone or ball mills with pre-grinder
(the most commonly used pre-grinder is the mechanical crusher). Coal grinding has also gradually
shifted to VRM use, while a few older facilities still operate with air-swept ball mills. With an increased
use of petroleum coke and imported coal and, therefore, enhanced coal fineness requirements, VRMs
are gradually becoming the most preferred option for coal mills.
The selection of grinding mill type depends mostly on the moisture content and material hardness.
VRM, widely accepted for the combined drying and grinding of moist raw materials and coal and for
low energy consumption, has been widely used for all three grinding requirements. Several
improvements in design and operation of the mill and other equipment in the grinding circuit are
resulting in less energy consumption and improved reliability.
Anticipated benefits of this paper:
• Electrical saving: 6 - 10 kWh/MT Cement
• CO2 reduction potential: 7 – 12 kg CO2/MT Cement
Current Status
Material grinding is the largest electrical energy consumer in cement manufacture. Therefore the Indian
cement industry, where energy costs contribute to a majority share in overall cement manufacturing
costs, has adopted the most energy efficient technology for its grinding requirements.
The recent plants (installed in the last 10 years and contributing over 50% of cement manufacturing
capacity) have VRM for raw material and coal grinding and VRM/ball mill with HPGR for cement
grinding.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
Plant 1
Plant 2
Plant 3
Electrical savings possible (kW/MT Cement)
12.3
6.2
2.5
Annual energy savings (Million INR)
53.8
65.1
58.8
Investment requirement (Million INR)
CO2 reduction potential (MT CO2/Annum)
235
59
70.1
14210
15857
13785
Raw material, Coal & Cement Grinding combined together
Replication potential
Average
potential
2.1
0.75
Replication
potential
251
0.75
Thermal savings possible (kCal/kg clinker)
0.0
0.0
Electrical savings possible (kW/MT Cement)
4.67
4.67
Annual energy savings (Million INR)
59.7
5275.0
Investment requirement (Million INR)
89.1
11605.0
Plant Capacity MTPA Cement
Average clinker factor
CO2 reduction potential ( MT CO2/Annum)
14336.9
CO2 reduction potential ( Million MT CO2/Annum)
1.17
4.4 Topic 4 - Retrofit uni-flow burner with advanced multi-channel burner
Background
Compared to a simple uni-flow burner, modern multi-channel burners offer better possibilities for flame
shape control because of their separate primary air channels (swirl air and axial air). This allows for the
adjustment of primary air amount and injection velocity, independent of the coal injection. The most
important flame control parameters are primary air momentum and amount of swirl. A high momentum
will give a short, hard flame, whereas a low momentum will make the flame longer and lazy. Swirl will
help create recirculation in the central part of the flame, stabilizing the flame and giving a short ignition
distance. Higher swirl, however, can cause high kiln shell temperatures due to flame impingement on
the burning zone refractory. A good swirl control system is therefore important. The best solution would
be a system wherein swirl could be adjusted independent of the momentum.
Compared to a conventional burner, modern multi-channel burners offer much better possibilities for
flame shape control, a high momentum, and the flexibility to use different types of fuels, such as liquid
or solid biomass. Advanced burners reduce the loss in production during kiln disturbances and also
reduce NOx in the burning zone as the primary air ratio is low. NOx emissions can be reduced as much
as 30–35% over emissions from a typical direct fired, uni-flow burner. Better flame properties with the
multi-channel burner improve combustion efficiency and eliminate flame impingement on refractory.
Anticipated benefits of this paper:
• Thermal savings: 3-5 kCal/MT Clinker
• Electrical saving: 0 – 0.5 kWh/MT Clinker
• CO2 reduction potential: 2 – 4 kg CO2/MT Cement
Current Status
The Indian Industry’s increased focus on energy efficiency and preparedness for increased alternative
fuel utilization has resulted in the industry gradually shifting from uni-flow (or mono-channel) burners
to multi-channel burners. Several cement kilns have installed multi-channel burners either by design or
as a retrofit in their pursuit of energy efficiency improvements.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
All kilns covered under the present study are operating with latest generation multi-channel burner
for coal firing.
4.5 Topic 5 - Energy efficiency improvement in process fans
Background
Precise design specifications, reduced margins between requirement and procurement, and a choice of
appropriate control systems can result in significant energy reduction during design stage. Several
studies indicate that excess margins buffered in at various levels are one of the major reasons for
deviation between design specifications and operating requirements. Experts suggest that optimum
margins for capacity and heat should not be over 10%, which otherwise results in an enhanced power
consumption of about 25%. To curtail this margin and offer precise process controls, the choice of an
appropriate speed control device becomes essential. Speed control is the most effective way of capacity
control in centrifugal equipment; the choice of right speed control mechanism offers additional margins
for efficiency improvements.
Among the various options available for speed control of Medium Voltage (MV) drives for process
fans, such as Grid Rotor Resistance (GRR) control, Slip Power Recovery Systems (SPRS), and so on.
MV Variable Frequency Drives (VFD) are found to be the most suitable speed control mechanism,
considering the precise control offered and the low inherent system energy losses. Hence, for all major
fans, the right selection of fan with MV VFD as a preferred speed control offers the maximum energy
saving.
Anticipated benefits of this paper:
• Electrical saving: 4 – 6 kWh/MT Cement
• CO2 reduction potential: 5 – 8 kg CO2/MT Cement
Current Status
Process fans are large electrical energy consumers in cement manufacture, second largest to grinding.
India’s cement industry has focused on process fans for several years in its pursuit for increased energy
efficiency, and has reduced operating costs in the process.
In a number of plants, high energy efficient fans have replaced inefficient process fans by both design
and by retrofit with speed control devices, eliminating the control damper.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
Electrical savings possible (kW/MT Cement)
Annual energy savings (Million INR)
Investment requirement (Million INR)
CO2 reduction potential (MT CO2/Annum)
Plant 1
1.72
7.48
20.9
1974
Plant 2
3.27
34.4
49.8
6892
Plant 3
2.3
54.2
93.8
12702
Replication potential
Average
potential
2.1
0.75
Replication
potential
251
0.75
Thermal savings possible (kCal/kg clinker)
0.0
0.0
Electrical savings possible (kW/MT Cement)
2.46
2.46
Annual energy savings (Million INR)
43.3
2779.0
Plant Capacity MTPA Cement
Average clinker factor
Investment requirement (Million INR)
73.7
CO2 reduction potential ( MT CO2/Annum)
5532.5
9904.6
CO2 reduction potential ( Million MT CO2/Annum)
0.62
4.6 Topic 6 - Energy efficiency improvement in auxiliary equipment in the cement
manufacturing process
Background
Auxiliary equipment such as conveyors, elevators, blowers, compressors and pumps, consuming about
10% of total electrical energy of cement manufacturing process, are vital for transporting the material
and gases from one manufacturing stage to another. For enhanced energy efficiency, the optimum
performance of auxiliary equipment becomes important within the overall energy performance of the
manufacturing facility.
The new technological advancement proposed under this paper includes Pipe conveyors, Centrifugal
blower, Centrifugal compressors, high efficiency pumps, VFDs for pumps & screw compressors,
Wobbler screen for crusher and Automation of auxiliary equipment
Anticipated benefits of this paper:
• Electrical saving: 0.5 – 1 kWh/MT Cement
• CO2 reduction potential: 0 – 1 kg CO2/MT Cement
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
Annual energy savings (Million INR)
Plant 1
2.97
13
Plant 2
1.8
18.9
Plant 3
1.44
34
Investment requirement (Million INR)
19.8
27.9
34.9
CO2 reduction potential (MT CO2/Annum)
3452
3772
8683
Electrical savings possible (kW/MT Cement)
Replication potential
Average
potential
2.1
0.75
Replication
potential
251
0.75
Thermal savings possible (kCal/kg clinker)
0.0
0.0
Electrical savings possible (kW/MT Cement)
1.73
1.73
Annual energy savings (Million INR)
27.6
1954.0
Investment requirement (Million INR)
31.2
2622.1
Plant Capacity MTPA Cement
Average clinker factor
CO2 reduction potential ( MT CO2/Annum)
6821.3
CO2 reduction potential ( Million MT CO2/Annum)
0.43
4.7 Topic 7 - Energy efficiency improvement in captive power plants
Background
The estimated average auxiliary power consumption in cement industry’s CPPs ranges from 10–13%,
whereas the best operating CPPs in the Indian cement industry operate at 5.8–6% of auxiliary power
consumption. A similar range is also observed in the CPP heat rate; the average heat rate of all CPPs
installed in the Indian cement industry is about 3200 kcal/kWh, and in the range of 2,550–2,575
kcal/kWh in the better operating plants.
With such a large proportion of cement plants operating with CPP with such a wide variation in auxiliary
power consumption and heat rate values, this offers an excellent lever for energy efficiency
improvement and Greenhouse Gas (GHG) emissions reductions. Energy efficiency in CPPs could be
achieved in two ways: energy efficiency by design and energy efficiency by retrofit.
Anticipated benefits of this paper:
• Thermal savings: 100 – 250 kCal/kWh
• Electrical saving: 20 – 30 kWh/MW of CPP capacity
• CO2 reduction potential: 0.05 – 0.1 kg CO2/kWh
Current Status
In its pursuit for reliable and high quality electrical power, over 53% capacity of India’s cement industry
has adopted CPP for their internal power requirements. The initial trend was to explore heavy oil-fired
diesel generator sets to meet part demand in the event of grid failure. With a sharp rise in fuel oil prices
and frequent outages of the grid, the industry has now completely shifted to coal / lignite and petroleum
coke-based thermal power plants as the preferred CPP option.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
Plant 1
Plant 2
Plant 3
Electrical savings (kW/MW)
24.9
13.18
5.8
Thermal Savings (kCal/MW)
19.5
Annual energy savings (Mi)
17.3
15.6
25
Investment requirement (Million INR)
42.1
27.8
18.4
CO2 reduction potential (MT CO2/Annum)
4583
3134
8797
Replication potential
Average
potential
2.1
Replication
potential
251
21514
Thermal savings possible (kCal/kWh)
12.3
12.3
Electrical savings possible (kW/MW)
10.42
10.42
Annual energy savings (Million INR)
21.8
10187.0
Investment requirement (Million INR)
24.2
16813.9
Plant Capacity MTPA Cement
Plant Capacity MW
CO2 reduction potential ( MT CO2/Annum)
6931.2
CO2 reduction potential ( Million MT CO2/Annum)
2.64
4.8 Topic 8 - Increased renewable energy use in cement manufacture
Background
India today ranks among the world’s top five countries in terms of Renewable Energy (RE) capacity
with around 20 GW installed base. This represents about 11% of India’s total power generation capacity
(an increase from 3% – 11% in the last decade). Future targets are promising: Government of India
(GoI) targets to achieve over 20% of the country’s total power generation in the next decade through
renewable sources with an installed capacity of over 70,000 MW. GoI has also recently launched two
unique and ambitious national missions; the National Solar Mission which seeks to facilitate the
generation of 20,000 MW of solar power by 2022, and the National Biomass Mission which aims to tap
bioenergy potential of over 25,000 MW.
Anticipated benefits of this paper:
• Thermal savings: Nil
• Electrical saving: 30% of electrical energy offset through RE use
• CO2 reduction potential: 24 kg CO2/MT of Cement (for 30% use of RE)
Replication Potential
Reference
Plant
2.1
Replication
potential
251
75.0
75.0
157500
18825000
15750.00
1882500.00
RE installed capacity , MW
47.68
5698.93
Annual energy savings (Million INR)
1271.5
151971.5
Investment requirement (Million INR)
3814.4
455914.6
CO2 reduction potential ( MT CO2/Annum)
15750.0
1882500.0
Plant Capacity MTPA Cement
Electrical SEC , kW / MT Cement
Annal Electrical energy consumption , MW
Annual Electrical energy utilisaton Through RE, MW
CO2 reduction potential ( Million MT CO2/Annum)
1.88
4.9 Topic 9 - Energy efficiency improvement in electrical systems
Background
Intelligent Motor Control Centers (MCC) and Energy Management Systems (EMS) occupy a prominent
role in control schemes, housing a comprehensive array of control and monitoring devices. MCCs have
moved rapidly to include the latest component technologies, and integrating these advanced
technologies presents a major opportunity – to transform islands of data into useful information that
minimizes operational downtime.
With Average loading of around 50–70% in most of the systems,, voltage optimization can yield
substantial energy savings. Lighting voltage generally observed in industry is on the higher side; but
can be reduced to around 210–215 V without decreasing the lux levels too much.
Frequency optimization also holds strong potential if the plant is not synchronized with the grid and is
running in ‘island mode’. Plants can operate with as low as 48Hz as the generating frequency. The key
technologies proposed in this paper includes energy management systems, use of EFF 1 premium
efficiency motors, LED and Magnetic induction lamps, Improving power factor, Voltage optimization
in motors and lightings and frequency mode optimization.
Anticipated benefits of this paper:
• Thermal savings: Nil
• Electrical saving: 1 – 3 kWh/MT of Cement
• CO2 reduction potential: 1.5 – 4 kg CO2/MT of Cement
Current Status
Some of the plants in the Indian cement industry are already equipped with the latest available
technology in electrical systems, like intelligent Motor Control Centers (MCC) and Energy
Management Systems (EMS); and so on. Such technologies can be replicated in other plants.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
Plant 1
Plant 2
Plant 3
Electrical savings (kW/MW)
0.21
2.52
1.378
Annual energy savings (Mi)
0.9
26.5
32.5
Investment requirement (Million INR)
2.4
27.8
38.3
CO2 reduction potential (MT CO2/Annum)
247
5302
7601
Replication potential
Average
potential
2.1
0.75
Replication
potential
251
0.75
Thermal savings possible (kCal/kg clinker)
0.0
0.0
Electrical savings possible (kW/MT Cement)
1.50
1.50
Annual energy savings (Million INR)
27.0
1694.0
Investment requirement (Million INR)
31.1
2763.6
Plant Capacity MTPA Cement
Average clinker factor
CO2 reduction potential ( MT CO2/Annum)
CO2 reduction potential ( Million MT CO2/Annum)
6099.3
0.38
4.10 Topic 10 - Utilization of advanced automation systems in cement manufacture
Background
An effective advanced automation and control system can bring substantial improvements in overall
performance of the kiln, increased material throughput, better heat recovery and reliable control of free
lime content in clinker. Furthering the scope of automation in process control, quality is also maintained
by continuous monitoring of the raw mix composition with the help of x-ray analyzer and automatic
proportioning of raw mix components. New types of on-line bulk material analyzers have also been
developed based on Prompt-Gamma-ray Neutron Activation Analysis (PGNAA) to give maximum
control over the raw mix. The analyzer quickly and reliably analyzes the entire flow online providing
real time results. The latest trends in online quality control include computers and industrial robots for
complete elemental analysis by x-ray fluorescence, x-ray diffraction techniques, online free lime
detection, and particle size analysis by latest instrumental methods.
The control and operation of kiln systems today is extremely complex, with properties of input fuel and
feed materials varying greatly and with product standards becoming increasingly stringent. Cement kiln
operators today encounter such sudden variations that dynamic control of the kiln is vital to achieve
optimum results and lower manufacturing costs.
Grinding systems are also undergoing significant improvements, more from their operation as the
grinding technology has been witnessing only incremental improvements over the last several years.
Automation and control systems can significantly improve the performance of grinding systems by
reducing the variations, maintaining precise particle size distribution and increasing throughput.
Anticipated benefits of this paper:
• Thermal savings: 6 - 8 kCal/MT Clinker
• Electrical saving: 3 – 6 kWh/MT Clinker
• CO2 reduction potential: 4 – 8 kg CO2/MT Cement
Current Status
The recent plants in the Indian cement industry (installed in the last 10 years and contributing over 50%
of cement manufacturing capacity) are operating with advanced process control. Potential exists in older
plants to improve energy efficiency by adopting latest control systems.
Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study
All plants covered under study were operating with latest generation control systems for raw
material, coal and cement grinding and kiln operation.
Replication Potential
Plant Capacity MTPA Cement
Electrical SEC Saving potential , kW / MT Cement
Reference
Plant
2.1
Replication
potential
251
1.0
1.0
Replication Potential across the industry, %
50.0
Annual Electrical energy saving, MW
2100.00
125500.00
Annual energy savings (Million INR)
9.5
564.8
Investment requirement (Million INR)
18.9
1129.5
2100.0
125500.0
CO2 reduction potential ( MT CO2/Annum)
CO2 reduction potential ( Million MT CO2/Annum)
0.13
4.11 Topic 11 -Increasing thermal substitution rate in Indian cement plants to 30%
Background
Several nations globally have utilized cement kilns as an effective option for their country’s industrial,
municipal and hazardous waste disposal. This creates a win-win situation for both the local
administration and the cement plants: the administration utilizes the infrastructure already available at
cement kilns, thereby spending less on waste management, and the cement kilns are paid by the polluter
for safe waste disposal, as well as having their fuel requirements partly met.
If the TSR in the Indian cement industry could increase to 30% by, for example, 2030, GHG emissions
could reduce substantially; to such an extent that it could make a difference in the overall country’s
emissions. The typical types of wastes being used as alternative fuels are industrial wastes (automotive,
pharmaceutical and engineering industry wastes being the most common) and biomass-based fuels.
Anticipated benefits of this paper:
• Thermal savings: 0 - 40 kCal/MT Clinker (Increase)
• Electrical saving: 0 – 6 kWh/MT Clinker (Increase)
• CO2 reduction potential (PPC) : 70 – 150 kg CO2/MT Cement (Net reduction)
• CO2 reduction potential (OPC) : 70 – 210 kg CO2/MT Cement (Net reduction)
Current Status
Alternative fuel use in the Indian cement industry is at very low levels; the country’s average stands at
less than 1% of Thermal Substitution Rate (TSR).
The Indian cement industry has limited experience of increased use of alternative fuel in its cement
kilns. Wherever alternative fuel has been used in Indian cement kilns (up to 10-12% TSR), it is largely
dominated by use of biomass. No / very marginal increase in energy consumption is observed in such
kilns at this TSR levels.
Cement kilns can exhibit significantly varying behaviour depending on the type of alternative fuel
substituted, and hence the technical competence of the industry should be adequate to face these
challenges which come alongside a TSR increase. With extensive national and global expertise
available, the Indian cement industry today is technically ready for adopting higher TSR rates.
Replication Potential:
Reference
Plant
2.1
0.75
715
Replication
potential
251
0.75
730
AFR Substitution % ,
1.0
1.0
Replication Potential across the industry, %
5.0
5.0
53625.00
6869300.00
Annual energy savings (Million INR)
53.6
6869.3
Investment requirement (Million INR)
225.0
28230.0
21549.5
2760469.4
Plant Capacity MTPA Cement
Average clinker factor
Thermal SEC, kcal / kg clinker
Annual thermal energy saving, Mkcal / annum
CO2 reduction potential ( MT CO2/Annum)
CO2 reduction potential ( Million MT CO2/Annum)
2.76
4.12 Topic 12 - Reducing clinker factor by increased use of fly ash in Portland Pozzolana Cement
(PPC) [Study conducted in one plant]
Background
The increased use of fly ash in Portland Pozzolana cement (PPC) directly affects the reduction of clinker
factor in cement (clinker factor : % of clinker content by cement mass), thereby reducing CO2 emissions
through reduced fuel combustion and reduced limestone calcination. Therefore, exploring newer
technical avenues for maximizing the utilization levels of fly ash represents the biggest challenge and
opportunity for CO2 reduction. The European standard (EN-197) for pozzolanic cement type IV/B and
South African standard SANS 50197 for pozzolanic cement type CEM IV B allows addition of siliceous
fly ash in the range of 36 – 55% which are more than the limit of 35% fly ash addition as per Indian
Standard IS: 1489 (Part I)-1991.
The plant under study is manufacturing PPC with 22 percent fly ash. Experiments were conducted at
the plant on increase of fly ash (as received) content as well as ground fly ash content. The results of
the experiments revealed that such increase in fly ash content resulted in marginal decrease in
compressive strength of the resultant PPC at all the ages. However, on the basis of these data, the fly
ash addition can be increased from 22 to 24 percent with enough margin in compressive strength value
(33.0 MPa at 28 days) specified in the standard specification, IS:1489-1991.
Recommendation and outcomes
It was recommended that the present level of 22 percent fly ash (as received) can be increased to 24
percent in manufacture of PPC.
Such increase in fly ash level will result in saving of:
• thermal energy ~13.42 kcal/kg,
• electrical energy~0.97kWh/t,
• CO2 reduction (direct) up to 16kg CO2/t, and
• CO2 reduction (indirect) ~0.97Kg CO2/t of PPC produced.
4.13 Topic 13 - Reducing clinker factor by increased use of granulated blast furnace slag (GBFS)
in Portland Slag Cement [Study conducted in one plant]
Background
The increased use of Ground Blast Furnace Slag (GBFS) in the manufacture of Portland Slag Cement
(PSC) has a direct impact on reducing the CO2 emissions, by decreasing specific fuel consumption and
reducing limestone calcination. GBFS is obtained as a by-product in the manufacture of pig iron in the
blast furnace of a steel plant. This GBF slag has latent hydraulic properties and the ability to reduce
heat evolution during cement hydration and therefore has a significant potential to replace clinker
content in cement in the manufacture of PSC. The quality and performance of PSC is governed by the
Indian standard specification IS:455-1989, which allows use of GBFS in the range of 25- 70% (4th
amendments). The European standard (EN-197) for blast furnace slag cement type III/B and III/C
allows addition of ground GBFS in the range of 66-80% and 81-95% respectively, and similar limits
are followed in South African standards SANS 50197 for blast furnace slag cement type CEM III B and
CEM III C which are more than the limit of 70 % GBFS addition as per Indian standard IS: 455.
The plant under study is manufacturing PSC utilizing 57 percent of GBFS. The results of experiments
conducted at plant indicated that value of compressive strength at 28 days was found to be increased
with increasing GBF slag content to 59 percent. However, further increase in the GBF slag content
resulted in decrease of compressive strength.
Recommendation and outcomes
The GBF slag addition of 59 percent can be considered as optimum at the GBF slag fineness level of
370 m2/kg.
Such increase of 2% utilization level will result in saving of:
• thermal energy ~13.5 kcal/kg cement,
• electrical energy ~ 1.0kWh/t,
• CO2 reduction (direct) up to 16kg CO2/t, and
• CO2 reduction (indirect) ~0.9 Kg CO2/t PSC.
4.14 Topic 14 - Reducing clinker factor by the use of low grade limestone in manufacture of
Portland Limestone Cement (PLC) [Study conducted in one plant]
Background
Portland Limestone Cement (PLC) has a good techno-economic potential using low/marginal grade
limestone, dolomitic limestone and so on. PLC is fairly popular in the USA and Europe and has been
standardized and codified in European standards (EN). It is a type of blended cement on similar lines
to PSC and PPC. As per European standard EN-1971, two types of Portland limestone cement
containing 6-20% limestone (type II/AL) and 21-35% limestone (type II/B-L) are specified and
produced. PLC’s have many advantages like a) reducing GHG emissions during cement manufacture,
b) conserving fast-depleting cement grade limestone reserves, c) utilizing hitherto unused low grade
limestone not suitable for cement manufacture and d) reducing energy consumption during finish
grinding (limestone being softer to grind compared to clinker).
The results of the experiments conducted at the plant on Portland Limestone Cement (PLC) revealed
that the cement containing limestone showed substantial increase in Blaine’s fineness. The compressive
strength development at 28 days in the samples containing 8 and 11 % limestone (CaCO3~70%) content
was found to be near to control OPC (without limestone addition). However on addition of 17 and 20
percent limestone, the strength values were found to be reduced by 8 to 10% at the ages of 3, 7 & 28
days along with slight increase in setting time as compared to OPC. The water requirement for
consistency was found to be substantially increased from 27.5 to 32 % on addition of limestone in OPC.
However, the physical characteristics of resultant cement samples were found to conform to the
requirements as specified for OPC-53 grade. Therefore, PLC blend prepared with 20% limestone
addition can be considered as acceptable composition.
Recommendations and outcomes
Considering enough saving in thermal and electrical energy with big reduction in CO2 emission (direct
& indirect), the manufacturer of Portland Limestone cement (PLC) utilizing low grade limestone
content up to 20 percent was recommended.
Manufacture of such cement will result in:
• thermal saving ~129.2 kcal/kg cement,
• electrical saving~ 8.36 kWh/t,
• CO2 reduction (direct) up to 152kg CO2/t, and
• CO2 emission (indirect) ~8.36 Kg CO2/t.
4.15 Topic 15 - Exploring the feasibility of producing composite cement using two or three
blending components for achieving lower clinker factor in blended cements [Study conducted in
one plant]
Background
Blended cements, which are produced using more than one mineral addition, are known as 'composite
cement'. At present, the Bureau of Indian Standards has no specific standard for composite cements.
European standards identify composite cements (CEM V), where both granulated blast furnace slag
(GBFS) and siliceous fly ash/ Pozzolanic material are used together as cement replacement materials.
For the European cement type ‘Portland Composite Cement (type II /A-M and II /B-M)’, European
Standard EN 197 specifies the use of a number of mineral admixtures such as GGBFS, silica fume,
natural and industrial pozzolana, siliceous and calcareous fly ash, burnt clay, limestone, etc. in the range
of 6-20 % for type II/A-M and 21-35 % for type II/B-M cements respectively. The American Society
for Testing of Materials (ASTM) has also introduced performance-based specifications for hydraulic
cements with no restrictions on cement composition (ASTM C 1157-00, Standard Performance
Specification for Hydraulic Cement). Such freedom in the choice of mineral additives is useful for both
optimizing/controlling the performance of cement and maximizing the use of mineral admixtures
leading to lower CO2 emissions and greater sustainability.
To facilitate the manufacture and use of composite cement in India it is required to formulate the
standards for composite cements. Investigations on performance and durability characteristics of
composite cements prepared from indigenous materials and tested as per BIS specifications would be
required to generate enough data to enable formulation of standards on composite cements.
The results of the experiments conducted at the sample plant on composite cement samples containing
clinker-30.5%, GBF Slag-47%, fly ash-18% and gypsum-4.5% was found to show improvement in
compressive strength as compared to Portland Slag Cement, PSC containing GBF slag-57%, clinker38% and gypsum-5%. The other properties such as consistency and setting time were more or less
comparable.
Recommendations and outcomes
Adopting the manufacture of composite cement using above combination can result in saving of about
7.5 percent clinker compared to PSC manufacturing.
Also, the manufacture of composite cement using such composition could result in saving of:
• thermal energy of about 51 Kcal/kg, and
• CO2 reduction of about 7.5 kg CO2/tonne cement.
4.16 Topic 16 - Waste Heat Recovery at a cement plant
The major use of thermal energy in a Cement Plant is in the kiln and pre-calciner systems. In the dry
process cement plants nearly 40 percent of the total heat input is rejected as waste heat from exist gases
of preheater and grate cooler. In most of the plants part of the waste heat is utilized for drying of raw
material and coal, GBF Slag but even after covering the need for drying energy in most of the cases,
there is still waste heat available which can be utilized for electrical power generation. The waste heat
recovery (WHR) system, effectively utilizes the available waste heat from exit gases of pre-heater and
clinker cooler. The WHR system consists of Preheater boiler, Air Quenching Chamber (AQC) boiler,
steam turbine generator, distributed control system (DCS), water-circulation system and dust-removal
system etc. NCB team collected preliminary data through WHR questionnaire, Process flow diagrams,
CCR screenshots.
There exists a potential to generate power of at least 30 KW/MT of clinker production. Waste heat
recovery installation payback varies from case to case basis.
Case 1: Waste heat recovery installation becomes very attractive for various plants which are operating
with grid electricity, as power generation would offset purchased power.
Case 2: Waste heat recovery installation becomes moderately attractive for plants planning for
installation of coal based captive power plant to meet electricity requirements. Waste heat recovery in
such cases can reduce the captive power plant capacity. Or for plants exporting power to grid from
captive power plants can export additional power generated from waste heat recovery systems.
Case 3: Waste heat recovery installation becomes difficult due to longer payback periods for plants
already having excess capacity in captive power plant and operating with lower PLF, further power
generation capacity addition with waste heat recovery installation would result in further reduction in
PLF.
Replication Potential
Reference
Plant
2.1
Replication
potential
150
30
30
Average clinker factor
0.75
0.75
Clinker production capacity MTPA
1.57
112.5
Generation potential (MW)
5.9
422
Investment requirement (Million INR)
590
4220
47250
3375000
Plant Capacity MTPA Cement
Average power generation potential (KW/MT of
clinker)
CO2 reduction potential ( MT CO2/Annum)
CO2 reduction potential ( Million MT CO2/Annum)
3.37
5.0 Conclusion
The outcomes of the unit level assessment study of Low Carbon Technology Roadmap study for 3
Indian Cement Plants indicate potential to reduce 130 Kg CO2/MT of cement.
Paper
Electrical and thermal energy
efficiency improvements in kilns and
preheaters
Latest generation high efficiency
clinker coolers
Energy efficiency in grinding systems
Retrofit uni-flow burner with advanced
multi-channel burner
Energy efficiency improvement in
process fans
Energy efficiency improvement in
auxiliary equipment
Energy efficiency improvement in
(CPP)
Increased Renewable Energy (RE) use
for cement manufacture
Energy efficiency improvement in
electrical systems
Utilization of advanced automation
systems in cement manufacture
Increasing Thermal Substitution Rate
Reducing clinker factor in fly ash based
Portland Pozzolona Cement (PPC)
Reducing clinker factor in slag based
Portland Slag Cement (PSC)
Reducing clinker factor by using low
grade limestone
Developing national standards on
composite cements
Waste heat recovery
Total
CO2
reduction
potential
(KgCO2/M
T Cement)
CO2
reduction
projections
Million
Tonnes
3.91
1.19
14.47
1.35
6.83
1.17
0.00
0
4.72
0.62
3.25
0.43
3.30
2.64
7.50
1.88
2.90
0.38
1.00
0.13
10.26
2.76
16.97
4.26
16.90
4.24
8.36
2.10
7.50
1.88
22.50
130.37
3.38
28.41
Barriers
Higher investment for newer
preheater and longer shutdown
period
Higher investment and layout
constraint
Longer payback period with
energy savings alone. Poor
market conditions
Poor PLF due to market
conditions. Coal unavailability
Higher investment
Lower RE costs
Higher investment for MV
VFDs
Waste availability, requirement
of preprocessing , waste
segregation and supportive
policy framework
Market demand for higher
strength Cement
Market demand for higher
strength Cement
Market demand for higher
strength Cement
Market demand for higher
strength Cement
Higher payback period
compared with CPP power and
layout constraints in few cases
This corresponds to 28.4 Million tons of CO2 reduction potential for entire Indian cement industry based
on the national cement production of 251 MTPA. The vision is realistic; but the targeted reductions
ambitious. The changes required must be practical, realistic and achievable. It is pertinent to note that
such ambitions are attainable only with a supportive policy framework and appropriate financial
resources invested over the long term. To achieve the envisioned levels of efficiency improvements and
emissions reduction, government and industry must take collaborative action. An investment climate
that will stimulate the scale of financing required must be created.