India Cements Sankarnagar Plant: Complete Technical Guide

This article is part of the Complete Cement Technical Package and covers, in a general and transferable form, the technical content of an integrated cement plant operations training and audit program of the type that a large multi-plant cement producer would apply at its production units. The operating excellence of a cement plant is not the result of any single technology but of the integration of the process, the equipment, the people and the management systems, and this article is written as a working guide for production managers, departmental heads, shift engineers and quality professionals who want to understand and apply that integration. It covers the process overview and the plant layout, the organization of the operations, the management of the raw materials and the quarry, the raw grinding, the kiln system, the cement grinding, the quality management, the maintenance strategy, the energy and the cost management, the safety and the environment, and the performance measurement and the improvement culture. The material is deliberately generic: it describes the best practice of the industry, the methods and the systems that any plant can adopt, and it does not describe the specific configuration or the performance of any particular company or plant. The reader will find in it the framework for the operation of a modern cement plant, from the quarry face to the despatch of the cement, and the practical tools for the continuous improvement of its performance.

The Integrated Cement Plant: Process Overview

The modern cement plant is a continuous process industry installation in which a handful of basic operations convert limestone and clay into cement. The process chain begins in the quarry, where the limestone and the clay are extracted, and continues through the crushing, the raw material storage and proportioning, the raw grinding, the homogenization, the preheating and the calcination in the kiln system, the clinker cooling and storage, the cement grinding with the additives, the cement storage, and the packing and despatch. Each of these stages is a production unit in its own right, with its own equipment, its own control system and its own operating crew, but the plant performs as a whole: the availability of the kiln depends on the raw meal supply, the quality of the cement depends on the clinker quality, and the cost of the product is the sum of the costs of all the stages. The integration of the stages, the buffers between them and the flows of the material, the energy and the information, is the object of the plant’s operations management.

The flow of the material is organized around the buffers. The quarry and the crusher feed the limestone stockpile, which buffers the variation of the quarry against the demand of the plant; the raw mill draws on the stockpile and feeds the raw meal silo, which buffers the mill against the kiln; the clinker silo buffers the kiln against the cement mill; and the cement silos buffer the mills against the despatch. The sizing of the buffers is a design decision, but their management is an operating decision: the plant runs best when each buffer is held in the operating band, not too low, which exposes the downstream to the upstream failures, and not too full, which wastes the storage and the working capital. The daily production planning, which balances the demand, the stocks and the equipment availability, is the first instrument of the integrated operation, and the production plan is the contract between the sales, the production and the maintenance departments.

The energy flows are the second dimension of the integration. The plant consumes the electrical energy for the drives, the fans and the compressed air, and the thermal energy for the kiln system, and the energy is the largest variable cost of the product. The energy flows are managed by the measurement: the plant energy metering, the specific consumption of each unit and the comparison with the targets, and the energy management system that identifies the waste and the improvement potential. The thermal energy of the kiln system, which is recovered in the preheater, the cooler and the waste heat systems, is the object of the heat balance, and the electrical energy of the grinding, which is the largest electrical consumer, is the object of the grinding optimization. The integration of the energy flows with the material flows, the planning and the quality, is the substance of the plant’s energy management, and it is one of the main levers of the plant’s profitability.

Organization of Plant Operations

The organization of the plant operations follows the classic structure of the process industry. The plant manager is accountable for the production, the cost and the safety; the production manager runs the day-to-day operation through the shift system; the maintenance manager runs the equipment care through the planned and the breakdown maintenance; the quality manager runs the laboratory and the quality assurance; and the engineering, the stores, the finance and the human resources functions support the operations. The shift organization, with the shift engineers and the operators for each unit, provides the continuous coverage, and the handover between the shifts, with the logbook, the shift reports and the verbal briefing, is the discipline that carries the continuity of the operation across the clock. The quality of the shift operation is decided by the training, the procedures and the supervision, and the best plants invest in their shift teams as the front line of the plant’s performance.

The accountability of the operation is expressed in the performance indicators. The plant KPIs include the production volumes, the kiln availability and the output, the specific heat and the electrical consumption, the quality parameters and their variation, the costs per tonne, the safety indicators and the environmental compliance. The indicators are cascaded from the plant to the departments and the shifts, with the targets set annually and reviewed monthly, and the performance reviews, at the plant, the department and the shift levels, are the management meetings in which the performance is compared with the targets and the corrective actions are decided. The performance culture of the plant is built on the honesty of the measurement: the indicators are meaningful only if the data behind them are accurate, and the data discipline, from the instrument calibration to the production accounting, is a management priority.

The management systems of the plant are the machinery of the integration. The plant operates under the quality management system, the ISO 9001 standard, with its procedures for the process control, the non-conformances and the improvement; under the environmental management system, the ISO 14001, with its procedures for the emissions, the waste and the compliance; and under the safety management system, with its procedures for the risk assessment, the permits and the training. The management systems are not paperwork: they are the institutionalized memory of the plant, the place where the experience is recorded, the standards are defined and the improvements are captured. The integration of the management systems with the operations, so that the procedures describe what is actually done and the records evidence what was actually achieved, is the difference between the certification and the management. The typical performance indicators of an integrated cement plant, with their characteristic ranges, are summarized in the table below:

Indicator	Typical range	Measured at	Managed by
Kiln availability	88–95%	Plant / kiln department	Maintenance and production planning
Kiln production rate	2,000–12,000 tpd	Kiln system	Kiln operation
Specific heat consumption	3,000–3,400 kJ/kg clinker	Kiln system	Kiln operation and fuel quality
Specific electrical consumption	85–120 kWh/t cement	Plant	All departments, grinding dominant
Kiln feed LSF standard deviation	0.02–0.04	Kiln feed	Raw material chain
Clinker free lime	0.5–2.5%	Clinker	Kiln operation
Cement Blaine	320–420 m2/kg	Finished cement	Cement grinding and quality
Lost time injury rate	Target zero; best practice < 1 per million hours	Plant	Safety management
Stack dust concentration	< 10–30 mg/Nm3	Stack	Dust collection and compliance

Quarry and Raw Materials Management

The quarry is the origin of the raw materials, and its management decides the quality and the cost of everything downstream. The quarry operation includes the geological exploration, the drilling and blasting, the loading and hauling, the crushing and the stockpiling, and the management of the mine life, the permits and the rehabilitation. The quality management of the quarry is the control of the limestone chemistry: the limestone is sampled and analyzed, the quarry plan blends the benches to the target chemistry, and the crusher feed is controlled so that the stockpile quality is within the band that the raw mill can use. The variability of the natural deposit is the fundamental fact of the quarry, and the management of the variability, by the exploration, the blending and the control, is the first quality function of the plant.

The secondary raw materials, the clay or the shale, the sand, the iron corrective and the additives, are managed with the same discipline: the sources are qualified, the deliveries are tested and the stocks are controlled. The proportioning of the raw materials is the beginning of the raw mix control: the weigh feeders of the raw mill blend the materials to the target mix, defined by the lime saturation factor, the silica ratio and the alumina ratio, and the control of the mix is the foundation of the clinker quality. The raw mix design is a quality function that integrates the quarry data, the process knowledge and the product targets: the mix is designed for the burnability of the materials, the fuel and the process conditions, and it is adjusted continuously as the materials change. The modern plants use the online analyzers at the crusher and the stockpile, which allow the automatic adjustment of the proportioning, and the plants without the online analyzers use the intensive sampling and the laboratory-based control.

The stockpile management is the buffer between the quarry and the raw mill. The stockpiles are managed by the chevron or the cone-shell stacking, which pre-blends the material as it is stacked, and by the reclaiming across the full face, which draws the blended material. The stockpile inventory is measured, the quality is sampled, and the reclaim strategy is planned so that the raw mill receives a stable feed. The practical issues of the stockpiles, the segregation, the moisture, the dust and the housekeeping, are the daily care of the raw material team, and their management is the condition of the stable operation of the raw mill and, through it, of the whole plant. The quarry and the raw materials management is a production discipline in its own right, and the plants that master it give themselves the stable foundation on which the kiln and the mills can perform.

Raw Grinding and Homogenization

The raw grinding converts the proportioned raw materials into the fine raw meal that the kiln system can process, and it performs three tasks at once: grinding the material to the target fineness, drying it to the target moisture, and homogenizing it in the process. The raw mill is either a vertical roller mill or a ball mill, with the vertical mill now the standard for the dry process, and its control includes the feed rate, the mill temperature, the classifier speed and the product fineness. The fineness target of the raw meal is typically 12 to 20% residue on 90 micron and 2 to 4% on 200 micron, and the moisture target is such that the meal flows and feeds evenly to the preheater. The raw mill uses the hot gas from the kiln system, the kiln exit gas or the preheater gas, as the drying medium, which integrates the mill with the kiln: the raw mill is operated in the combined or the direct mode with the kiln, and the gas flows are balanced between the mill, the preheater and the by-pass.

The homogenization of the raw meal is completed in the homogenizing silo, which reduces the fluctuations of the meal chemistry to the level that the kiln can absorb. The silo operates on the aeration principle: the meal is fluidized by the compressed air through the aeropoles, and the extraction pattern blends the meal to the outlet. The homogenization factor of the silo, the ratio of the inlet to the outlet variation, is typically 5 to 15 for the main components, and its achievement depends on the silo operation, the aeration pattern and the filling and extraction strategy. The kiln feed quality, the standard deviation of the lime saturation factor, is the output of the whole raw material chain, and its target, typically a standard deviation of 0.02 to 0.04 at the kiln feed, is the measure of the chain’s performance. The raw material chain, from the quarry to the silo, is the first half of the plant’s quality system, and its stability is the condition of the kiln’s performance and the clinker’s quality.

The optimization of the raw grinding targets the specific energy, the reliability and the availability. The raw mill is typically the second-largest electrical consumer of the plant, and its optimization includes the mill internals, the grinding pressure and the classifier, the ventilation and the drying, and the control of the feed and the fineness. The mill availability is a production factor: the raw meal buffer is the protection against the mill stops, and its size, typically 12 to 24 hours of the kiln feed, is managed so that the kiln never waits for the meal. The maintenance of the raw mill, with the wear parts of the grinding table and the rollers, the classifier and the drives, is planned with the kiln stops, and the mill’s condition monitoring, the vibration, the temperature and the oil analysis, is the instrument of its care. The raw grinding is the quiet workhorse of the plant, and its performance is the foundation of the kiln’s.

Kiln System Operation

The kiln system is the heart of the plant, and its operation is the most demanding of the plant’s technical disciplines. The modern kiln system, the preheater, the calciner and the rotary kiln, converts the raw meal into clinker in a continuous process, and its operation is the management of the temperatures, the flows and the chemistry around the stable balance point. The control variables are the feed rate, the kiln fuel, the calciner fuel, the kiln speed, the draught and the cooler, and the controlled variables are the calciner exit temperature, the kiln exit gas temperature and oxygen, the burning zone temperature and the clinker quality. The operation is supported by the advanced control systems, the expert systems and the model-based optimization, but the foundation is the understanding of the process: the heat balance, the gas flows, the reactions and the circulation of the volatile components, all of which this article has treated in its kiln chapters.

The stable operation of the kiln is the condition of the clinker quality, the refractory life and the heat consumption. The clinker quality is controlled by the burning, the cooling and the chemistry: the free lime is the fast indicator, and its control at 0.5 to 2.5% is the primary quality target of the kiln operation. The refractory life, which is one of the largest cost items of the kiln system, is managed by the coating control, the flame shape and the shell temperature monitoring, and the refractory campaigns, the period between the relinings, are typically 8 to 24 months for the burning zone, depending on the operation. The heat consumption, typically 3000 to 3400 kJ/kg, is the energy efficiency of the system, and its control includes the excess air, the preheater efficiency, the cooler efficiency and the radiation losses. The kiln operation is therefore the balance of the quality, the cost and the reliability, and the operators are the managers of that balance.

The kiln system is also the source of the plant’s main emissions, and its environmental operation is part of the production operation. The dust, the NOx, the SO2 and the CO2 emissions are controlled by the process, the abatement equipment and the compliance systems, and the continuous emission monitoring reports the performance to the authorities. The alternative fuels, which many plants fire at high substitution rates, integrate the kiln system with the waste management economy, and their management, from the fuel quality to the process chemistry, is a technical discipline that the kiln team owns. The kiln system operation is the plant’s central professional craft, and this package provides the reader with the complete technical material of that craft, from the combustion to the refractory to the control.

Cement Grinding and Quality

The cement grinding converts the clinker, the gypsum and the additives into the finished cement, and its operation decides the product quality, the energy cost and the dispatch reliability. The cement mill, the ball mill or the vertical mill, is operated in the closed circuit with the separator, and its control includes the feed rate, the mill conditions, the separator speed and the fineness. The fineness of the cement, the Blaine and the residue, is the primary quality parameter, but the modern quality control extends to the full particle size distribution, which the laser diffraction measures, and to the cement performance, the water demand, the setting, the strengths and the workability. The cement quality is the final product of the plant, and its consistency is the reputation of the plant in the market.

The cement types are produced by the variation of the clinker content, the fineness and the additives. The ordinary Portland cement, the Portland pozzolana cement with the fly ash or the natural pozzolana, the Portland slag cement and the composite cements cover the market, and their production is managed by the quality plan: the clinker and the additive proportions, the fineness targets and the quality testing are defined for each type, and the mill set-ups, the separator settings and the feed blends are the operating expression of the plan. The changeover between the types is a production operation, with the purge of the mill and the silos and the verification of the quality before the dispatch. The cement storage and the dispatch, the silos, the packing machines and the bulk loading, complete the plant, and their operation includes the inventory management, the quality segregation and the logistics of the orders.

The optimization of the cement grinding targets the specific energy, which is the largest electrical cost of the plant, typically 30 to 40 kWh per tonne. The levers are the mill internals and the media, the separator efficiency, the ventilation and the temperature, the grinding aids and the blend design: the additives and the fineness are optimized against the quality requirements and the cost of the components. The clinker quality from the kiln is the starting point of the cement grinding: a well-burned, well-cooled clinker grinds more easily, and the kiln and the mill are linked by the grindability of the clinker. The cement grinding is the last production stage, and its discipline, from the sampling to the dispatch, is the last gate of the plant’s quality, and the plants that run it well deliver the consistency that the market rewards.

Quality Management in the Plant

The quality management of the cement plant is organized around the laboratory, the sampling and the process control. The laboratory performs the sampling and the analysis of the raw materials, the raw meal, the clinker and the cement, with the classical wet chemistry, the X-ray fluorescence and diffraction, and the modern instruments of the fineness and the particle size. The sampling plan defines the points, the frequencies and the methods, and the accuracy of the sampling and the analysis is the foundation of everything: the quality decisions, the process adjustments and the product certification. The laboratory is organized for the continuous operation, with the shift analysts and the rapid methods that give the process control its data, and its quality system, the inter-laboratory comparisons and the certified reference materials, verifies the accuracy of its results.

The process control integrates the laboratory data with the plant operation. The control loops adjust the proportioning, the kiln firing and the mill settings against the targets, and the control charts and the statistical process control show the variation and the drift. The non-conforming product, whether the raw meal out of band, the clinker with a high free lime or the cement off spec, is managed by the non-conformance procedure: the identification, the assessment, the disposition and the record, with the disposition options of the reblending, the reprocessing or the rejection. The quality of the shipped product is certified by the quality certificate that accompanies each shipment, and the customer complaints are the feedback loop that closes the quality system. The quality management of the plant is therefore a complete loop, from the quarry to the customer, and its operation is the daily practice of the quality department and the whole plant.

The improvement of the quality is the reduction of the variation. The variation of the product, the raw meal, the clinker and the cement, is the enemy of the quality, because the plant must operate with a margin above the specification limits to be safe, and the margin is the give-away: the extra fineness, the extra strength or the extra clinker factor that costs money. The reduction of the variation is achieved by the stabilization of the process, the control of the inputs and the statistical analysis, and the quality department’s role is the measurement, the analysis and the leadership of the improvement. The modern plants use the online analyzers, the process models and the advanced control to reduce the variation at the source, and the quality culture, in which every operator understands the link between their operation and the product quality, is the final instrument of the quality management.

Maintenance Strategy and Execution

The maintenance of the plant is organized on the principle that the availability of the equipment is a production resource, and its strategy balances the preventive, the predictive and the corrective maintenance. The preventive maintenance, the scheduled inspections, the lubrication and the replacement of the wear parts, is the backbone: the equipment is maintained on the defined cycles, and the maintenance plan is the calendar of the plant. The predictive maintenance, the condition monitoring with the vibration, the thermography, the oil analysis and the non-destructive testing, detects the developing failures before they cause the breakdowns, and its use extends the intervals and reduces the surprises. The corrective maintenance, the repair of the failures, is minimized by the first two, and its management, the breakdown response, the root cause analysis and the modification, closes the loop of the reliability improvement.

The maintenance execution is organized around the stops and the campaigns. The annual kiln stop is the major event, in which the kiln refractory, the preheater internals, the cooler and the related equipment are inspected and repaired, and its planning, the scope, the resources, the materials and the schedule, is a project that runs for months. The mill stops, the shorter events, are planned with the same discipline, and the daily and the weekly maintenance is planned against the production plan so that the equipment is maintained without the loss of the production. The spare parts management is the logistics of the maintenance: the critical spares, the long-delivery items and the consumables are managed with the reorder points and the stock levels, and the stores operation is the support of the maintenance execution. The maintenance performance is measured by the availability, the reliability and the maintenance cost per tonne, and the maintenance department is accountable for these indicators like the production department for its own.

The reliability improvement is the long-term objective of the maintenance. The failure analysis, the Weibull analysis of the failure data, the root cause analysis of the major failures and the modification of the weak designs, systematically reduce the failure rates, and the maintenance history of the equipment, recorded in the maintenance management system, is the data of the analysis. The plants with the mature maintenance organizations achieve the kiln availabilities above 92%, the mill availabilities above 90% and the maintenance costs that decline in real terms, and they achieve them through the discipline of the planning, the condition monitoring and the analysis. The maintenance is not the cost center that the production avoids; it is the partner of the production, and the integration of the two, in the planning, the stops and the improvement, is the condition of the plant’s performance.

Energy and Cost Management

The energy management of the plant is organized around the measurement, the targets and the improvement. The plant energy metering measures the electrical and the thermal energy of each unit, and the energy accounting reconciles the consumption with the production and the specific consumption with the targets. The heat balance of the kiln system quantifies the thermal losses, the exit gas, the radiation, the cooler and the clinker, and its periodic measurement is the instrument of the thermal improvement. The electrical energy of the grinding, the fans and the auxiliaries is the object of the motor efficiency programs, the fan and the pump optimization and the power factor management. The energy targets, the specific heat and the electrical consumption per tonne, are set against the best practice, and the gap analysis identifies the improvement projects, which are implemented and verified by the measurement. The energy management is a continuous program, and its results, the reductions of 5 to 15% in the specific consumption, are among the largest cost savings available to the plant.

The cost management of the plant extends beyond the energy to the materials, the consumables and the overheads. The production cost per tonne is the aggregation of the raw materials, the fuels, the power, the media and the liners, the packaging, the labor and the overheads, and the cost accounting allocates the costs to the products and the units. The cost control is the management of the variable costs, the consumables, the media and the fuels, against the standards, and the cost analysis, the variance analysis against the budget, identifies the deviations and their causes. The cost culture of the plant, in which every department is accountable for its consumption and its costs, is the organizational instrument of the cost management, and the cost reviews, at the plant and the department levels, are the management meetings in which the costs are compared with the budget and the actions are decided.

The integration of the energy and the cost with the production planning is the essence of the plant management. The production plan is made against the demand, the stocks and the costs: the grinding is scheduled in the low-tariff periods where the tariffs allow, the kiln is operated at the most efficient rate, and the product mix is planned against the margin of each product. The plant’s profitability is the result of the production volume, the price of the product and the cost of the production, and the plant management’s role is the optimization of the triangle, within the constraints of the quality, the safety and the environment. The annual budget, the production and the cost plans, and the monthly reviews are the instruments of the plant management, and the plants that run this cycle rigorously are the plants that deliver the consistent profitability that the industry expects.

Safety and Environmental Management

The safety of the plant is the first priority of its management, and the safety management system organizes the plant’s protection of its people. The risk assessment identifies the hazards of the operation, the confined spaces, the hot work, the heavy machinery, the dust, the heights and the traffic, and the controls are engineered and procedural: the guards, the interlocks, the permits, the procedures and the training. The permit-to-work system controls the high-risk activities, the entry into the confined spaces, the hot work in the hazardous areas and the work at height, and its discipline is non-negotiable. The safety indicators, the lost time injuries, the recordable incidents and the near misses, are measured and reviewed, and the safety culture, in which the safety is the responsibility of every employee and the reporting of the hazards and the near misses is encouraged, is the objective of the plant’s safety program. The safety performance of the cement industry has improved dramatically, and the plants with the best performance demonstrate that the target of zero harm is a management choice, not an accident of the conditions.

The environmental management of the plant covers the emissions to the air, the water and the land, and its organization follows the environmental management system. The air emissions, the dust, the NOx, the SO2 and the CO2, are measured by the continuous monitoring and the periodic testing, and the abatement equipment, the bag filters, the SNCR and the other systems, is operated and maintained for the compliance. The water management covers the process water, the cooling water and the wastewater, with the recycling and the treatment, and the land management covers the waste, the quarry rehabilitation and the housekeeping. The environmental performance is reported to the authorities and to the public, and the permits and the compliance are managed as a legal obligation and a business obligation. The environmental improvement, the reduction of the emissions and the resource use, is also an operational improvement: the dust is the lost product, the water is a cost, and the energy is the largest environmental input.

The integration of the safety and the environment with the operations is the final condition of the plant’s license to operate. The safety and the environmental management are not separate from the production; they are the constraints and the conditions within which the production is performed, and the management of the plant, from the operators to the plant manager, is accountable for them as for the production itself. The plants that manage the safety and the environment rigorously find that the discipline carries over into the production performance, because the same rigor that prevents the accidents prevents the breakdowns and the losses. The safety and the environmental management are therefore not the cost of the production but the foundation of its sustainability, and this article has set out to place them in that position in the reader’s understanding of the plant.

Performance Measurement and the Improvement Culture

The performance measurement of the plant is the instrument of its management, and the performance indicators, cascaded from the plant to the departments and the shifts, are the language of the performance. The indicators are grouped in the balanced categories: the production, the quality, the cost, the availability, the safety and the environment, and the target-setting and the review cycles, daily, weekly, monthly and annually, create the rhythm of the management. The data behind the indicators must be accurate and timely, and the data management, the meters, the records and the accounting, is the foundation of the measurement. The performance reviews are the management meetings in which the results are compared with the targets, the deviations are analyzed and the actions are decided, and the review discipline, with the follow-up of the actions, is the difference between the review and the ritual.

The improvement culture of the plant is the systematic application of the improvement methods. The Kaizen culture, the continuous small improvements by the teams at the working level, is supported by the suggestion systems and the improvement teams; the lean methods, the elimination of the waste in the flows and the processes, are applied to the material handling and the maintenance; and the six sigma and the statistical methods are applied to the quality and the process variation. The improvement projects are selected against the plant’s priorities, the biggest gaps and the biggest opportunities, and they are executed with the project discipline: the problem definition, the measurement, the analysis, the implementation and the verification. The improvement is institutionalized by the documentation: the improved procedures, the standards and the training, so that the improvement is not lost with the people who made it.

The learning organization is the final element. The plant’s experience, recorded in the procedures, the reports and the failure analyses, is its institutional memory, and the training and the development of the people, from the operators to the engineers, are the investment in that memory. The plants with the strongest performance are the plants that learn the fastest: they measure, they analyze, they act and they record, in a cycle that never stops, and their performance compounds over the years. The integrated cement plant operations, which this article has described from the quarry to the dispatch, are the sum of the process, the equipment, the people and the systems, and the improvement culture is the force that raises the sum. The reader who applies the framework of this article, the measurement, the analysis and the disciplined action at every level of the plant, will find that the plant’s performance responds, and that the operation of a cement plant, which this article has presented in its full scope, is one of the most rewarding disciplines of the process industry.

Frequently Asked Questions about Cement Plant Operations

What are the main production units of a cement plant?

The quarry and the crushing, the raw material storage and proportioning, the raw grinding, the homogenization, the kiln system with the preheater, the calciner and the cooler, the clinker storage, the cement grinding, the cement storage and the packing and despatch. Each unit is operated and optimized as part of the integrated chain.

What is the most important quality parameter of the kiln operation?

The free lime of the clinker is the fast indicator of the burning: the target is typically 0.5–2.5%, and its control is the daily quality objective of the kiln team, supported by the full clinker analysis and the microscopy.

How is the raw material quality controlled?

By the quarry blending, the stockpile management, the proportioning control at the raw mill and the homogenization in the silo. The kiln feed quality, with a standard deviation of the lime saturation factor of 0.02–0.04, is the output of the whole raw material chain.

What is the largest electrical consumer of the plant?

The grinding, the raw and the cement mills, together with the fans of the kiln system, are the largest electrical consumers, and their optimization, with the specific energy of 25–40 kWh per tonne, is a priority of the energy management.

How is the maintenance planned with the production?

The maintenance is planned against the production plan, with the annual kiln stop as the major event and the mill stops and the daily maintenance integrated into the production calendar. The availability targets, above 90% for the main units, are the shared objectives of the production and the maintenance.

What is the key performance indicator of the plant efficiency?

The production cost per tonne, together with the specific heat and the electrical consumption, the quality variation and the availability, the safety and the environmental indicators. The plant is managed against the cascade of these indicators, reviewed at the defined cycles.

Summary and Final Recommendations

The operation of an integrated cement plant is the combination of the process engineering, the equipment care, the quality management and the people leadership, and this article has presented the complete framework of that combination. The recommendations for the plant leadership are these: manage the material flows and the buffers, because the integration of the units is the plant; stabilize the raw material chain, because the kiln cannot be better than its feed; master the kiln operation, because the clinker quality and the heat consumption are decided there; optimize the grinding, because the energy and the quality of the product are decided there; maintain the equipment for the availability, because the production is the product of the reliability; measure the performance honestly, because the management is the management of the data; and build the improvement culture, because the compounding of the small improvements is the path to the excellence. The integrated plant is a system, and its management is the management of the system, in which every department, every shift and every operator contributes to the whole. This article has aimed to give its readers the complete picture of the plant and the discipline of its operation, so that the plants they manage produce their cement at the highest quality, the lowest cost and the highest safety, year after year.

This file is part of the Complete Cement Technical Package (931 files) available from cementequipment.org. Respective rights holders; library copy for the licensed single user.