Repair & Retrofitting
Though the Indian cement industry is highly efficient when it comes to energy consumption, rising fuel costs is pushing the industry to consume less and save more. The data available from various sources indicates that the thermal energy consumption and their specific electricity consumption of Indian cement industry is definitely better than the rest of the world average. The cement industry´s average specific electrical energy consumption is 82 kWh/tonne of cement compared to the world average in the range of 100-110 kWh/tonne of cement. Average specific thermal energy consumption is 725 kcal/kg of clinker compared to the world average of about 850-860 kcal/kg clinker. However, opportunities abound when it comes to energy efficiency. One can consider upgrading old plants, co-processing industrial and municipal waste in cement kilns, generating power from the waste heat in kilns, and using waste from other industries like fly ash and slag in the manufacturing process. Use of alternate fuels and raw materials (AFR) is a major potential area for improvement.
Cement industry in India has a history of inception in the first decade of the 20th Century with a 30 tpd cement plant and has seen gradual movement till 1950 with capacity accounting for 3.2 mtpa. A thrust has been given for the capacity expansion post-independence but under different regulation. Since 1989, when the market was deregulated, the overall market has seen tremendous growth in subsequent years and at present stands at 363 mtpa.
According to Manoj Thakur, Head - Mechanical, Penta India Cement and Minerals, the health of modern plants is better than that of the older plants. It varies considerably from one cement factory to another and depends on a number of influencing factors, such as the age and condition of the equipment, the number and size of individual kiln lines, plant capacity utilisation, mode of plant operation, expertise of maintenance personnel and external costs, as well as the applied maintenance and servicing concept. He says, "The approach to maintenance planning differs greatly from company to company and in the past years of global economic crisis, many companies drastically reduced their planned maintenance to a minimum or only included measures that would provide immediate benefits. However, most of the major cement manufacturers have been adopting the best manufacturing practices by optimising energy, resources and the technology. Though the Indian cement industry is considered among the most advanced in the world in terms of technology and practices, the potential to save energy and emission does exist through various efficiency improvement pathways. The Indian cement industry, being the second largest in the world, is globally competitive."
Says DT Arjun, Vice President - Business Development & Projects, Walchandnagar Industries Ltd (WIL), "As far as technology and equipment are concerned, it´s a mix of both old and new, in process of phasing out the old technology and adopting advance and efficient system. As we observe the market, we feel part of the industry is still running inefficiently with old age equipment." He adds, "In due course of time, cement production technology has taken a giant leap in terms of localised system modification to technological improvement, which is being termed as upgradation.
According to Arjun, the major upgradation project is broadly classified in three categories:
-Category I: Substantial production improvement by retrofit/expansion.
-Category II: Relatively smaller modification to adopt the technological advancement
-Category III: System upgradation to comply with environmental/social/government norms.
He adds, "We have in-depth knowhow and competencies for all the three categories and provide state-of-the-art solutions. In Category I, we offer pyro upgrade, which helps our customers to even double their operating capacities by addition of new pre-heating (PH) tower coupled with cooler upgrade. In Category II, WIL offers close circuiting of cement mill with dynamic separator and numerous other like PH cyclone modification, cooler inlet modification to improve the operational efficiencies. These solutions are perfect match for the system installed with the technologies prior to 80s. WIL is committed for energy conservation and has devised an array of solutions to use alternative fuel, reuse of waste heat which primarily falls under Category III." According to him, the Indian cement industry has understood the need of the hour that is obvious from the different upgrades happening around in all the three categories.
Elaborating on the different types of upgradations that are being carried out at various cement plants, Thakur says, "Indian cement industry is undergoing rapid technological upgradation including modernisation and improvement of plant processes. Capacity increase of dry process plants, modernisation of grinding units, waste heat recovery units, automation/electrical solutions, etc., are the most important upgradation measures being taken up by Indian cement players. There is a long list of other plant upgradation and modernisation measures being carried out, such as revamping of pollution control equipment, fans, storage and conveying equipment, loading and packing facilities, etc. In the scenario of shortage of skilled labour, many plants are moving from manual material handling to automated and mechanised material handling solutions. Adding to this, some plants are undergoing the refurbishment of production lines also after lengthy shutdowns and closures.
Preventive & predictive maintenance
Says Thakur, "Indian cement industry is gradually moving from breakdown maintenance to preventive maintenance. In today´s scenario, focus of many of the cement players have diverted to following factors such as increased production levels, rigid production schedules, increased machine utilisation, and market competition. This emphasises the need of an effective and strategic maintenance system which is lacking at many plants. In the absence of a robust maintenance system, there are several undesirable consequences such as excessive machine breakdown, shortened lifespan of the facility, frequent emergency maintenance work, panic operating changes, disproportionate investment in spare parts and tools/tackles, poor utilisation of staff, etc.
According to him, another important but neglected area is the de-dusting system. He says, "Lack of the proper de-dusting system and its maintenance leads to emission at various points violating the environmental norms and further to even plant closures. However, on a positive note, he adds, "Many of the Indian cement players strictly follow maintenance strategies to upkeep their plant, machinery and equipment." "The history of cement industry in India is quite old and gradually, the industry has acquired enough knowhow about installed systems. At WIL, we see at present the cement manufacturers are doing fairly good in terms of predictive maintenance of cement plant," says Arjun. He adds, "Cement plants are like any other mechanical commodity, which needs periodic health check to identify the operational shortfalls, if any. In general, a plant goes for routine maintenance practice, which may or may not identify minor operational/mechanical problems, which keep on accumulating with time. As a system supplier, we foresee this smaller negligence as a prominent cause for failure. WIL has done a detailed investigation of the same and has prepared a tailor-made package to assess the plant health and suggest suitable action termed as Mechanical & Process Assessment and Optimisation (MPAO)."
Says Indranil Dutta, Head (E&A), Burnpur Cement, "We stand in the top category in the rank order scaling of predictive plant maintenance. The predictive maintenances (PdM) are carried out when the machines are running in their normal production modes. Some process plants have a weekly shutdown and this is for their preventive maintenance (PM) activities. Though on an average, these PM and PdM have tentative same type of nature, i.e., mainly machine inspection and other lubrication related jobs. But most important, if PdM carries out in a plant, it reduces the shutdowns which in turn increases production."
Thakur sums up on a positive note, "It is expected with the current government´s thrust on housing and infrastructure development that cement demand is expected to grow in the near future. This is an opportunity for cement players to take necessary steps to meet the foreseen market demand, be it taking action towards improving their plant availability by way of predictive maintenance of core machinery and structures, or taking decision on capacity upgradation by retrofits or new installations. This appears to be the right time for cement manufacturers to speed up their planning process and take appropriate actions in order to be ready to deliver."