The growing demand of AFR in cement industry
The growing demand for fuel and raw material in the cement industry can be partly satisfied by using different alternative fuels and raw (AFR) materials. Many cement plants across the country have already started using AFR and a few are in the process of setting up systems to use AFR. The Government of India has also come up with initiatives through Central and State Pollution Control Boards (CPCB and SPCBs) that aim to increase AFR use in the cement industry.
Details on fuels used in 2010 were not available during the year of preparation of the LCTR. Over the years, petcoke consumption has increased steadily in the Indian cement industry. Coal use (Indian and imported) has been declining over the years and petcoke and alternative fuels are gradually replacing it. In 2017 the share of coal was 41 per cent while that of petcoke was 56 per cent and alternative fuels was 3 per cent. Changes in the fuel mix have lowered carbon intensity by 2 kgCO2/t cement. The overall emissions factor (for coal and petcoke) decreased to 94.1 kgCO2/GJ in 2017 from 94.7 kgCO2 /GJ in 2010.
Alternative fuel use (thermal substitution rate - TSR) increased from 0.6 per cent in 2010 to 3.7 per cent in 2015 and then dropped to 2.7 per cent in 2017. The upward trend in alternative fuel use tapered off in 2016 and 2017 due to the comparative increase in prices of certain alternative fuels, making them uncompetitive to use instead of conventional fuels. This trend is expected to reverse and climb in the years to come due to improved economics. More than 60 cement plants in India have reported continual use of alternative fuels. The sector consumed more than 1.5 million tonnes of alternative fuels in 2015. Biomass is 24 per cent of the total alternative fuel consumed.
The increased use of petcoke can be attributed to its higher calorific value (around 8,000 kcal/kg) as compared to Indian coal (3,500-4,500 kcal/kg) and the economic advantages derived from affordable pricing models. For the same amount of heat, the quantity of petcoke required is less than that of coal, which leads to savings in transport costs, considering the quantities of fuel transported. Petcoke use also increases the overall life-span of mines as the industry can use marginal grade (quality) limestone with a low lime saturation factor (LSF) (due to less ash content). In about 10 cement plants, petcoke consumption is more than 95 per cent.
Market changes and improvements observed
Many plants have started co-processing waste as alternative fuels by setting up co-processing facilities. Seven cement plants have set up pre-processing facilities to convert non-homogeneous wastes into alternative fuels with the desired quality parameters. The total investment by these seven plants is more than Rs 2.5 billion. Regulatory drivers have also accelerated the co-processing of waste by cement companies. The Ministry of Environment Forests and Climate Change (MoEFCC) issued its Solid Waste Management Rules in 2016. These rules give preferential status to the co-processing of waste as a management option. Some SPCBs have approved inter-state transportation of hazardous waste to encourage co-processing. Together, these have resulted in increasing alternative fuel use.
Indian cement plants have used different types of waste as alternative fuels. Solid waste is 73 per cent of total alternative fuel use. The major types of solid waste used are carbon black, tire chips, refuse-derived fuel (RDF), captive power plant (CPP) bed ash and dolachar.
There is significant potential for higher rates of RDF use generated from municipal solid waste (MSW). About 80 per cent of the estimated 62 million tonnes of MSW generated in India is indiscriminately disposed of in dump sites.ix In a business-as-usual (BAU) scenario, India will require a landfill area of 8,800 hectares by 2050. This is equivalent to the size of the city of New Delhi. By using 25 per cent AFR by 2050 (as per the objectives of the LCTR), the cement industry can contribute to a 26 per cent reduction in the space required for landfilling.
Policy driver: Solid Waste Management Rules 2016
The MoEFCC recently notified its new Solid Waste Management (SWM) Rules 2016. These replace the Municipal Solid Wastes (Management and Handling) Rules 2000. One of the major highlights of the new rules is the promotion of waste-to-energy in cement plants using co-processing systems. The rules mandate that all industrial units using fuel and located within 100 kilometers of a solid waste-based RDF plant must make arrangements within six months from the date of notification of these rules to replace at least 5 per cent of their fuel requirement by RDF.
The rules also direct that non-recyclable wastes having a calorific value of 1,500 kcal/kg or more need to be used to generate energy at waste-to-energy plants or giving it away as feed stock for the preparation of refuse-derived fuel for cement kilns. High-calorific wastes shall be used for co-processing in cement or thermal power plants.
The CPCB has released a comprehensive set of guidelines on ôPre-processing and co-processing of hazardous and other wastes in cement plantsö as per the Hazardous and Other Waste (Management and Transboundary Movement) Rules 2016, via a notification dated 7 July 2017. The proposed guidelines are in line with the recently notified Hazardous Waste Management Rules (HWM) 2016 wherein companies must consider prevention, reuse, recycling, recovery and use, including pre-processing and co-processing, prior to considering disposal through incineration or secured landfilling. The objective behind this measure is to ensure millions of tonnes of hazardous, municipal and agricultural waste is either properly recycled or disposed sensibly in order to reduce India's overall environmental footprint. It is preferable to use cement kilns to dispose of hazardous wastes due to longer retention times, high temperatures and the absence of residual ash or byproducts.
Although various industrial processes allow for the use of wastes as a resource or for energy recovery, co-processing in cement kilns is considered an effective and sustainable option because of its dual benefits û as a supplementary fuel source and as an alternative raw material. Furthermore, the biomass content of alternative fuels is considered carbon neutral.
As per the proposed guidelines, such use would help in recovering the energy and material values present in them by reducing the consumption of primary fossil fuels and raw materials.
The following attributes of the recently released guidelines have been a major driver for Indian cement companies to increase the use of AFR in their plants:
Authorisation for pre-processing and/or co-processing: Under the proposed guidelines, SPCBs)/Pollution Control Committees (PCCs) may grant authorisation to cement plants to co-process different kind of wastes listed in the Hazardous and Other Wastes (Management and Transboundary Movement) Rules 2016.
Trial runs: Fresh trial runs for the co-processing of hazardous wastes already tested and in the system, would not be necessary as per the proposed guidelines, except for a few specific wastes, such as persistent organic pollutants (PoPs), polychlorinated biphenyls (PCBs), obsolete and date-expired pesticides, ozone depleting substances (ODS), etc.
HWM Rules 2016, streamline the approval process for the co-processing of hazardous waste to recover energy and put it on an emission norms basis rather than on a trial basis.
The Guidelines adopt a waste management hierarchy and resource recovery principles and include recommendations on the use of RDF in cement plants. They also include suitable standards for RDF along with guidance for different stakeholders.
The estimated quantity of MSW-based RDF and mapped cement plants within 100 and 200 kilometers of urban areas highlight the use potential of RDF in cement plants. The Guidelines map MSW processing facilities across the country to facilitate faster implementation between Urban Local Bodies (ULBs) and the cement industry. To create a viable business model, they define the financial needs, gaps and instruments for fiscal incentives. These Guidelines should enhance the use of MSW-based RDF in the cement industry in the future.
Challenges to implementation
Although cement kilns could technically completely replace conventional fuels with alternative fuels, there are some practical limitations. The physical and chemical properties of most alternative fuels differ significantly from those of conventional fuels. It may not be directly used because of low calorific value, high moisture content, or high concentrations of chlorine or other trace substances. This means pre-treatment is often needed to ensure a more uniform composition and optimum combustion. For Indian cement plants to increase TSR by 25 per cent (in 2050), a major barrier is cost of material sourcing and acquisition. The cost of sourcing the material should be regulated by applying polluter pays principle. Higher fuel substitution will take place if waste legislation restricts landfilling and dedicated incineration and allows controlled collection and treatment of alternative fuels.
The main technical barrier is the adverse impact created on kiln production and specific energy consumption. The companies are in the process of developing a complete understanding of the impacts of minor constituents and what effects they might have on long-term cement performance. The government must provide incentives for the use of RDF derived from municipal solid waste and biomass to promote high-volume use of these AFRs to meet the 25 per cent TSR target by 2050.
One of the key policy barriers that existed at the time of the launch of the LCTR in 2013 was the absence of a legislative framework that encourages co-processing in the cement industry. With the SWM Rules 2016 and their clear objective to promote co-processing and pre-processing of waste, this barrier has ceased to exist. However, other major policy barriers for increased use of AFR include the non-existence of structured industrial ecosystems for waste co-processing and inconsistent legislative requirements for cement kilns and their dedicated waste processing facilities.
The industry requires a future-forward approach to promote waste co-processing. Some of the desired interventions include:
The implementation of proper segregation and collection of dry and wet waste from households and commercial and industrial establishments.
User fees for waste generators (including households) and their use for managing MSW and cement-grade RDF generation.
Government support of ULBs in implementing integrated waste management systems.
Government permission to freely move wastes from state to state.
Government efforts to create awareness and promote high levels of waste use through waste management awards and recognition through avenues including print media, school programmes, etc.
Detailed waste generation inventory at the industry/ULB level (including contact persons) with yearly updates.
Capacity building for all stakeholders (cement plants, policy-makers, waste generators, government officials, local communities, etc.) about waste co-processing.
The development of environmental professionals in waste management.
Long-term partnerships between cement manufacturers and ULBs to use RDF from MSW, including pre-processing platforms in public-private partnership (PPP) models in all cement clusters.
Alternative fuel feeding platform and processing
Many cement plants are installing co-processing and pre-processing platforms to increase alternative fuel use. One plant in Madhya Pradesh has installed a pre-processing platform consisting of a shredder, belt conveyors, pay loaders, separators and screens, and increased TSR from 0.64 per cent to 8.8 per cent. The total investment was around Rs 620 million. The plant uses various wastes, such as agricultural waste (rice husks, soya husks), saw dust, plastic waste, RDF, effluent treatment plant (ETP) sludge, spent carbon, carbon black, etc. Plants in the states of Karnataka, Chhattisgarh, Rajasthan, Gujarat, Maharashtra and Tamil Nadu have also installed co-processing and pre-processing platforms.
SOURCE: Excerpts from the Low Carbon Technology Roadmap for the Indian Cement Sector: Status Review 2018, published by World Business Council for Sustainable Development (WBCSD).