GHG REDUCTION POTENTIALS IN THE INDIAN CEMENT INDUSTRY UPSCALING IMPLEMENTATION

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1 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 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 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, CO 2 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 CO 2

2 emissions to an industrial average of tco 2/t cement in 2010 from a substantially higher level of 1.12 tco 2/t cement in In order to further reduce CO 2 emissions, four key technology levers have been identified which can contribute to reduction in CO 2 emissions. These form the basis of a lowcarbon technology roadmap for the Indian cement industry which was launched in February 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 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 : 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 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 CO 2 intensity of cement production, CSI worked with the IEA to develop the first industry roadmap. That roadmap outlines emissions reduction 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 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 GtCO 2 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 GtCO 2 and 1.1 GtCO 2 in This represents a direct emissions reduction 1 of about 0.28 tco 2/ t cement produced from 0.63 tco2/t cement in 2010 to 0.35 tco2/t cement in Such a reduction in emission intensity would limit the increase in CO 2 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.

3 reduction in clinker-to-cement ratio, a radical step change in new technology development to bring 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 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 s. 4.1 Topic 1 - Electrical and thermal energy efficiency improvements in Kilns and preheaters 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. Thermal savings: kcal/kg Clinker Electrical saving: 2-3 kwh/mt Clinker CO 2 reduction : 7-10 kg CO 2/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 Kiln 1: 4300 Kiln 2: 4145 Kiln 3: 3585 Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Clinker) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction (MT CO 2/Annum)

4 : Average Average clinker factor Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Clinker) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 2: Latest generation high efficiency clinker coolers Retrofitting of existing conventional reciprocating grate coolers with latest generation coolers offers a significant 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 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 %. Thermal savings: kcal/kg Clinker Electrical saving: 0-1 kwh/mt Clinker CO 2 reduction : 8-10 kg CO 2/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 %, depending on the mechanical condition and process operation of the cooler. This corresponds to a total heat loss from the cooler of about 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 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 Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Clinker) Annual energy savings (Million INR) Investment requirement (Million INR)

5 CO 2 reduction (MT CO 2/Annum) Average Plant Capacity MTPA Cement Average clinker factor Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Clinker) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 3: Energy efficiency in grinding systems 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. Electrical saving: 6-10 kwh/mt Cement CO 2 reduction : 7 12 kg CO 2/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) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction (MT CO 2/Annum)

6 Raw material, Coal & Cement Grinding combined together Average Average clinker factor Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Cement) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 4 - Retrofit uni-flow burner with advanced multi-channel burner 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. Thermal savings: 3-5 kcal/mt Clinker Electrical saving: kwh/mt Clinker CO 2 reduction : 2 4 kg CO 2/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.

7 4.5 Topic 5 - Energy efficiency improvement in process fans 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. Electrical saving: 4 6 kwh/mt Cement CO 2 reduction : 5 8 kg CO 2/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 Plant 1 Plant 2 Plant 3 Electrical savings possible (kw/mt Cement) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction (MT CO 2/Annum) Average Average clinker factor Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Cement) Annual energy savings (Million INR)

8 Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 6 - Energy efficiency improvement in auxiliary equipment in the cement manufacturing process 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 Electrical saving: kwh/mt Cement CO 2 reduction : 0 1 kg CO 2/MT Cement 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) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction (MT CO 2/Annum) Average Average clinker factor Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Cement) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 7 - Energy efficiency improvement in captive power plants 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

9 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. Thermal savings: kcal/kwh Electrical saving: kwh/mw of CPP capacity CO 2 reduction : kg CO 2/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) Thermal Savings (kcal/mw) Annual energy savings (Mi) Investment requirement (Million INR) CO 2 reduction (MT CO 2/Annum) Average Plant Capacity MW Thermal savings possible (kcal/kwh) Electrical savings possible (kw/mw) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 8 - Increased renewable energy use in cement manufacture 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

10 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 of over 25,000 MW. Thermal savings: Nil Electrical saving: 30% of electrical energy offset through RE use CO 2 reduction : 24 kg CO 2/MT of Cement (for 30% use of RE) Potential Reference Plant Electrical SEC, kw / MT Cement Annal Electrical energy consumption, MW Annual Electrical energy utilisaton Through RE, MW RE installed capacity, MW Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 9 - Energy efficiency improvement in electrical systems 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 V without decreasing the lux levels too much. Frequency optimization also holds strong 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. Thermal savings: Nil Electrical saving: 1 3 kwh/mt of Cement CO 2 reduction : kg CO 2/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.

11 Outcomes of the unit level assessment study of Low Carbon Technology Roadmap study Plant 1 Plant 2 Plant 3 Electrical savings (kw/mw) Annual energy savings (Mi) Investment requirement (Million INR) CO 2 reduction (MT CO 2/Annum) Average Average clinker factor Thermal savings possible (kcal/kg clinker) Electrical savings possible (kw/mt Cement) Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 10 - Utilization of advanced automation systems in cement manufacture 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. Thermal savings: 6-8 kcal/mt Clinker Electrical saving: 3 6 kwh/mt Clinker CO 2 reduction : 4 8 kg CO 2/MT Cement

12 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. Potential Reference Plant Electrical SEC Saving, kw / MT Cement Potential across the industry, % 50.0 Annual Electrical energy saving, MW Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 11 -Increasing thermal substitution rate in Indian cement plants to 30% 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. Thermal savings: 0-40 kcal/mt Clinker (Increase) Electrical saving: 0 6 kwh/mt Clinker (Increase) CO 2 reduction (PPC) : kg CO2/MT Cement (Net reduction) CO2 reduction (OPC) : kg CO 2/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

13 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. Potential: Reference Plant Average clinker factor Thermal SEC, kcal / kg clinker AFR Substitution %, Potential across the industry, % Annual thermal energy saving, Mkcal / annum Annual energy savings (Million INR) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Topic 12 - Reducing clinker factor by increased use of fly ash in Portland Pozzolana Cement (PPC) [Study conducted in one plant] 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 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) 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: 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.

14 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] 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 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: , 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 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 m 2 /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 CO 2/t, and CO2 reduction (indirect) ~0.9 Kg CO 2/t PSC Topic 14 - Reducing clinker factor by the use of low grade limestone in manufacture of Portland Limestone Cement (PLC) [Study conducted in one plant] Portland Limestone Cement (PLC) has a good techno-economic 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.

15 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 CO 2 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 CO 2/t, and CO2 emission (indirect) ~8.36 Kg CO 2/t 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] 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 % 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 , 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%, clinker- 38% 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 CO 2/tonne cement.

16 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 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. Potential Reference Plant Plant Capacity MTPA Cement Average power generation (KW/MT of clinker) Average clinker factor Clinker production capacity MTPA Generation (MW) Investment requirement (Million INR) CO 2 reduction ( MT CO 2/Annum) CO 2 reduction ( Million MT CO 2/Annum) Conclusion The outcomes of the unit level assessment study of Low Carbon Technology Roadmap study for 3 Indian Cement Plants indicate to reduce 130 Kg CO 2/MT of cement.

17 Paper CO2 reduction (KgCO2/M T Cement) CO2 reduction projections Million Tonnes 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 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 CO 2 reduction 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.