Bharathi Cement of Vicat Group uses Alternate Raw Materials and Fuels (AFR) extensively in its kilns. Milind Murumkar, Advisor, Vicat Group, speaks on the latest trends in this field.
How have things changed over the last 10 years in the field of Alternate Raw Materials and Fuels?
There have been remarkable changes in the last 10 years in the field of AFR in India. Thermal substitution has shown a very positive trend year-on-year, though at a very slow pace earlier, and picking up later in the last two-three years to a level of around 4 per cent.
The basic reasons for this can be broadly assigned to lack of knowledge on AFR usage in the Indian cement industry in early years, especially on usage of industrial waste, lack of skilled persons for handling & usage of industrial wastes, lack of proper infrastructure for storage & feeding of AFR materials to cement kilns, lack of proper understanding on the permitting process in regulatory bodies and above all, the will to receive and use waste materials in cement plants.
In the last two years, a remarkable transformation has been noticed in all the above aspects with dramatic changes in the mindset of regulatory bodies, plant operating professionals and also in the waste generators who are shifting to co-processing as a better option over land-filling and incineration as it provides a cost-effective option to them. In April 2016, with the revised Environment Ministry rules that incorporate co-processing as the better option for recovery of energy, the scenario is changing fast towards higher utilisation of different types of wastes in cement kilns.
Cement plants have also made proper investments to improve their infrastructure that can help in scientific disposal of industrial waste in the plants in a sustainable manner, for proper handling, storage and feeding of different types of wastes at appropriate points in the kiln system, without affecting the product quality and the environment.
In short, cement plants are focussing on higher usage of all types of waste and are reducing their dependency on conventional fuels and raw materials.
Tell us something on fingerprinting of AFR materials, and how and why it is done. After fingerprinting, how do you take care of variations in the incoming materials?
At a cement plant, we create systems for preparation of a homogenised raw mix that is fed to a kiln. Cement plants also need to know the characteristics of the waste that is to be co-processed and its compatibility with the raw material being used, to avoid process fluctuations and kiln operating instabilities.
Normally during the preliminary visit to the waste generators, one should try to understand the waste characteristics, the waste material safety data (MSD), etc. Proper samples are collected for analysis and reviewed if the waste can be co-processed or not. During the proposal and agreement finalisation with the waste generators, this aspect is considered for defining the quantities and the safety aspects of the waste.
Fingerprinting analysis is done to ensure that the waste is in line with the agreement and safe to be handled, stored and used in the required proportion that will not affect the product quality and the environment.
In the plants that are utilising higher quantities of wastes, it is desirable to have a proper waste fingerprinting analysis laboratory. Moreover in plants that are utilising different types of waste, it is also desirable to have a proper pre-processing facility for feeding a uniform quality of processed waste to the kiln system. Based on the quality of this processed waste, suitable changes in the raw material composition can be done to ensure that required balances in the material characteristics are effected before the material gets fed to the kiln system, for steady operation of kiln and uniform quality of desired product. A few third parties are also looking into creation of such pre-processing facilities for supply of processed waste to cement plants.
Give us more details on co-processing. Can alternate fuel alone be used as fuel?
Co-processing is a proven sustainable development concept that reduces dependency on natural resources and reduces pollution & landfill space, thus contributing to reducing the environmental footprint.
Co-processing is also based on the principles of industrial ecology, which consider the best features of the flow of information, materials, and energy of biological ecosystems, with the aim of improving the exchange of these essential resources in the industrial world.
AFR can also be used alone as fuel in cement kilns. A proper understanding of the processes, raw material characteristics and the waste compositions are the key factors that need to be assessed before use of AFR in a particular kiln system.
Benefits of Co-processing
Co-processing conserves natural (non-renewable) resources of energy and materials, reduces emissions of greenhouse gases, slowing global warming, and demonstrates a positive impact on integrated environmental indicators, such as the ecological footprint. Co-processing reduces the environmental impacts of the extraction (mining or quarrying), transporting, and processing of raw materials. It reduces dependence on primary resource markets. Co-processing saves landfill space and reduces the pollution caused by the disposal of waste. Moreover, co-processing destroys waste completely, eliminating potential future liabilities.
Provide us more information on the use of industrial waste as fuel. What have been the success factors and the failures? What has been the response from the industry?
As indicated earlier, with improvements in the permitting processes by regulatory authorities and the creation of proper infrastructure by cement plants, waste generators are also getting aligned for sending their waste to cement plants, as it is a much more cost-effective option for them. Many industrial sectors like pharmaceuticals, FMCG, automobiles, chemicals, metallurgical, plastics, etc., are sending their waste to cement plants.
A proper scientific waste assessment is needed that can provide a complete survey of the waste generated by an industry with a complete assessment of its suitability for co-processing.
There´s a need to have a dedicated laboratory for waste fingerprint analysis to analyse the waste in cement plants, to ensure that it is suitable for co-processing. The plant should be geared enough to manage waste such as solids, semi-solids, sludge and liquids, as waste generators normally prefer plants that can offer a complete solution to all their types of waste.
Waste transportation needs have to be well understood, ensuring that the waste is transported in appropriate packaging with required labelling and documentation. The waste is carried by operators with required skills, qualifications and permits. Pre-processing of different wastes is preferred to blend liquids, shred solid materials and homogenise waste, prior to usage in kilns.
There are facilities for co-processing of the pre-processed waste in cement kilns. Since cement kilns operate at temperatures of up to 2,000°C, there is no residue or waste after co-processing.
Give us some idea on the use of Municipal Solid Waste (MSW) as a fuel. What are the bottlenecks? Which municipal corporations have made some planning in this direction?
Large quantities of MSW are available in India in every state and in every city. They can be used in cement plants if proper segregated MSW as RDF (Refuse Derived Fuel) is made available to them. The basic difficulty is the quality of RDF that is being generated at the RDF plants. The RDF produced from MSW in these plants is highly heterogeneous with moisture to the tune of 30-40 per cent, which creates problems of conveying and usage in cement plants. The problems of these RDF plants are in the input MSW material received by them and they have no control on these receipts. Some cement plants have created facilities for usage of RDF by investing in pneumatic or mechanical conveying systems and yet the usage is very low due to high moisture and the heterogeneity of material. The RDF producing plants are trying to develop systems for improving the quality to some extent, but largely no concrete steps are being taken by municipalities for improving the quality of RDF going to cement plants.
However, some concrete steps are being taken for installation of waste-to-energy plants for utilising segregated MSW for power generation. It is too early to comment on the success of these plants. We need further time to assess their performance and outcome. Even the authorities at the Central and state level are largely concerned with the menace of increasing MSW generation and proper disposal of this material, as large-scale environmental issues are cropping up at every MSW storage location.
Tell us about the success story at Bharathi Cement; what has been your TSR and at what location? What kind of alternate fuels do you use? What is the road ahead?
The success story of the Vicat Group is quite enviable compared to our peers. We started using AFR at our Kadapa plant in the year 2011 and there has been a four-fold increase in the TSR over the last four-five years. Today the substitution rate at our Vicat plants is 20 per cent. Huge investments have been made in creating world-class infrastructure at our plants for utilising different kinds of wastes which are hazardous and non-hazardous. Proper feeding systems have been provided as per the material characteristics and their forms like for liquids, semisolids & solids, RDF and plastic wastes etc.
The different kinds of waste we use in the plants are pharmaceutical waste, food & beverages/FMCG, black carbon and dolachar firewood, biomass (mango seeds), RDF from municipal solid waste, used tyres, etc. We have set up a well-equipped laboratory for proximate, ultimate and heavy metal analysis of waste. A team of 50 personnel is working for alternate fuels to increase the substitution rate. All our stacks and ambient air quality monitoring stations are well connected with the APPCB website. We have also arranged fire-fighting equipment, fire hydrant systems, etc. It is our commitment to reach a substitution rate of up to 40 per cent by end of 2020.
Milind Murumkar working as an Advisor AFR, Vicat Group, provides waste management solution. He had a long association with ACC Ltd in various disciplines. He has been successful in bringing regulatory changes in the waste management.