We in India often hear of the green revolution and the milk revolution but few recognise that we also have a real success story in the cement industry. Prior to the introduction of partial decontrol by the government in 1982, a bag of cement could be purchased in the black market at about Rs 150 when the controlled price against permit was a mere Rs 25. The fact that cement is freely available today at almost the same price per bag as it was 30 years ago is indeed also a revolution.Jayaram K Nambiar is associated with design, manufacture, supply, project planning and implementation of cement projects for the past 45 years. He currently serves as Director on the Board of Pfeiffer (India).With an installed capacity of 300 million tonne a year in 2011, India is the second largest cement producer in the world. The level of technology, processes and design of the plants is comparable to the best globally. The competence and knowledge of the people within the industry is second to none and the capacity utilisation, operating efficiencies and energy consumption results at the plants prove the same.Although substantial technology transfer has taken place in the period of growth, no real or worthwhile R&D in process technology or design development of equipment for cement manufacture is being undertaken in India. In not ploughing back returns – whether in terms of funding or knowledge gained – into R&D, the private sector cement producers and plant suppliers betray a short-sightedness that will in time erode the gains made over the last 30 years.Evolution of TechnologyUntil the 1980s, technology developments introduced were chiefly concerned with the reduction of thermal energy consumption – The pre-calcinator technology with the short kiln, pre-heater and high efficiency grate cooler developed at that time still remains the basic process of the top of the line clinker plants that are being constructed today.Subsequent developments emphasised savings in electrical energy. For example, new types of grinding equipment – vertical roller mills (VRM) and high pressure grinding rolls (HPGR) – are used in the three energy intensive operations, ie, preparation of raw materials and coal for the clinkerisation plant and for the grinding of the clinker into cement. Progressive improvements in the grinding circuits have been done to achieve further small gains in electrical energy by refinement of system engineering and streamlining of airflows. In clinkerisation the low pressure drop cyclones of the pre-heater and the high efficiency separators in grinding are outstanding examples of such development of streamlining of gas flows.The early 2000’s (2001-10) witnessed the commencement of a new trend – sharp increase in the capacity of the unit plant being installed from 6,000 tpd to 10,000 tpd – to take advantage of economies of scale by way of reduced investments.In view of the trend of installing high capacity plants a single grinding machine VRM with power as high as 12,000 KW transmitted through girth gear and multi-drive with variable speed motors was introduced in 2010 by Gebr Pfeiffer AG. The machine power of the VRM was earlier limited by the power transmittable by the VRM gearbox of around 7500 KW and this barrier now seems to have been overcome. In the future we can expect very large single unit VRMs of high capacity being installed for raw and cement grinding in plants of large capacity.The FutureAfter power, cement industry is the largest producer of CO2 waste accounting for 5 per cent of the total CO2 emitted worldwide. The Kyoto Protocol also applies to the cement industry and it gets, by way of subsidy, carbon credits for implementing CO2 reduction measures in the production process. The trend therefore from year 2000 was increasingly towards the production of blended cements (PPC and PBFS) which resulted in higher production capacity of cement being without the corresponding increase of CO2 emissions.Recent improvements being implemented in the cement Industry are environmental-friendly like waste gas heat recovery and production of blended cements described earlier will continue at more plants in the current decade. With the increasing acceptance of blended cement by consumers and with new power and steel plants being commissioned additional fly ash and slag would be available and the production of PPC and PBFS cement shall further increase.Future dust emissions norms set by the government are likely to be more stringent for the cement industry. The industry in anticipation has from the early 2000s started installing bag house filtration in place of ESP. Baghouses have reduced emission than the prescribed regulatory norms. Baghouses can be further enlarged quite easily and the technology will be able to match the tighter norms when next prescribed by the government.Cement companies in India have experimented with alternative fuels but sufficient headway has still to be made. The capability is available within the industry to handle successfully the process changes and develop the sustained utilisation of alternative fuels – wastes, biomass, etc but greater efforts has to put in this area. The situation in this regard can be expected to change as costs of coal go up and the collection and handling and thereby availability of waste materials improve, through collaboration across industry sectors and local government institutions. It has to be emphasised that the cement kiln with pre-calcinator is an ideal incinerator and by identifying specific available waste material and organising the long term use of it as an alternative fuel, the industry as well as society shall benefit. The importance of CO2 reduction for the cement industry cannot be under estimated and more developmental efforts have to be undertaken by the Indian cement companies in this direction.ConclusionsThe new plants coming up during this decade will have to consider new technological developments in the reduction of CO2 and other harmful emissions and in being environmentally-friendly. The design of these plants may well have to take into account new directions and regulations for the cement industry.Cement industry has been identified as one of the industries contributing to green house gases responsible for drastic climate changes. Global attention is focussed on climate change and international agreements on joint action for reduction of green house gases exist. What form such joint action will ultimately take will depend on the progress of technological developments underway (eg CCS), but before the end of the current decade some directions to the cement industry in relation to action required for a more environmental-friendly industry can be expected. Indian cement industry being the second largest will be required to be in the forefront of implementing these changes. Unfortunately, all the research and development which will decide the future direction is being undertaken in the developed countries and our Industry will continue to be dependant on technology transfer from others for implementing the required future changes and developments.