Economy & Market
Optimising plant utilisation
Published
11 years agoon
By
admin
Developments in pyro processing optimisation and technologies have made it possible to improve existing plants with high energy efficiencies and low emissions, while simultaneously reducing operating costs and preserving the environment and optimal use of fast depleting natural resources.
Kiln is said to be the heart of a cement plant, comparing the cement plant with that of human body. It is a continuous operation and the performance of a plant is judged by the number of days; the kiln runs without any stoppages. In the present economic scenario on an average, the plant utilisation is close to 70 per cent. For the operational function, it is much more challenging because if the production level further goes down for want of demand, then within no time, the plant operation runs into red. Therefore, it is extremely important to decide the equipment capacities precisely since it is a part of design. There is a tendency to go for higher capacity plants for the simple commercial considerations, but in the present situation, such plants in no time will turn into stressed asset if they are running below the bench mark level. Every unit knows its benchmark level to run it into profits. This is exactly the situation in few of the cement plants in the country as they were set up when there was a boom time for cement business which did last for few years but no further.
New approach
A few cement producers in the industry have been smart to decide on the capacities of the plant. Generally at design stage, while deciding on preheater it is preferred to have a single string of operation as a starting phase. Then after stabilisation and proper understanding of the market conditions, it is better to add another string. But then the kiln in the first phase must have been designed with sufficient margins. This has been the case with a few of plants in our country. The plant capacities have been enhanced over a period of time. Our design engineers along with FLSmidth, ThyssenKrupp, KHD Humboldt etc, have done wonderful jobs to add to the capacities of the plant in the country without diluting the performance of the kiln on any count like gaseous pollution or compromising on operational part. However, we strongly feel this has created tremendous load on the coolers and to some extent compromised its performance. The cooler as a hardware has limitations to enhance its capacity or either have modifications in the given space. In many cases, it has been noticed that it is the cooler which throttles the production and not the kiln or grinding.
Use of alternate fuels
Regarding the technology front, there is not much to say on the pyro process per se specifically that has happened in the last decade except more and more players in our country have been experimenting on alternate fuels or industrial waste which is encouraging. With more support coming from the government departments like Central Pollution Control Board (CPCB) and State Pollution Control Boards, the number of usage is only going to grow. There are some changes required in the kiln burner design before the fuels are changed or replaced. Plant would prefer to have a common burner for conventional fuel like coal and for alternate fuels like industrial waste and petcoke. The plants need to address the issue of safety while using hazardous waste since our experience in doing jobs in a safe manner is far below expectations.
Waste Heat Recovery (WHR) can reduce the operating costs and improve EBITDA margins of cement factories by about 10-15 per cent. On average, electric power expenses account for up to 25 per cent of total operating costs of a cement factory. However, to realise the full potential of WHR as of now $1,400 million is required, which is too high.
The other major advantage for Indian cement industry is minuscule presence of volatile matters like sulphur, chlorine, potassium etc. Therefor a majority of plants in India do not have bypass system as a part of design whereas the plants in Gulf countries have this as an additional system. In future as more and more plants will go for alternate fuels in the country they may have to go for by pass system as additional feature.
Focus emission
In pyro processing, the area of focus has been, reduction of NOX and SO2 emissions, and increase of production throughput without compromising on energy consumption but with flexible options on fuel.
Safety in pyro processing is extremely important since coal is used as a fuel. Generally, it is pulvisised at the plant and then fed into the kiln through burner. The conditions in the coal mill area are extremely hazardous and need more attention to reduce the number of unsafe incidences. Inertisation of coal mill is yet to be executed in many plants. There is a lot of scope for improvement here in the industry. Considering the capabilities exhibited till date, we feel Indian cement industry will fulfill this aspiration as well.
Conclusion
According to Kumar, developments in pyro processing optimisation and technologies have made it possible to improve existing plants with high energy efficiencies and low emissions, while simultaneously reducing operating costs and preserving the environment and optimal use of fast depleting natural resources. Process optimisation and performance improvement has become inevitable in cement industry. "Although every situation must be analysed carefully to evaluate real gains that can be achieved, most cement plants can achieve improved performance by implementing suitable modifications," he concludes.
TECHNOLOGY TRENDS IN PYRO PROCESSING
Kilns
- Redefinition of operating parameters – volumetric loadings up to 7.5 tpd/cu m
- Thermal loadings up to 5.5 Gcal/ sq m/kg clinker
- Filling % of 14-16 and kiln speeds up to 5.5 rpm
- 2-pier installations with a drop in L/D ratios to 10-11
- Low primary air, low NOx multi-channel burners
Pre-calciners
- Degree of calcination up to 95 per cent
- Calciner to kiln fuel ratio of 70:30
- Increased residence time up to 5.5 sec to improve combustion efficiency specially in case of petcoke
- Low NOx systems Pre-heater
- 6-stage, twin string preheaters with clinkering capacities up to 10,000 tpd
- Increased cyclone efficiency up to 96 per cent
- Reduction in L/D ratio in cyclones resulting in a pressure drop reduction from 700 to 400 mm WG and a tower height reduction of 10-15 m
- Reduction in the total sp. air requirement from 1.6 to 1.45 Nm3/kg clinker Improvement in fan efficiencies.
Coolers
- New generation (eg, walking-floor) coolers resulting in increased cooler recuperating efficiency from 68-76 per cent resulting in increase of secondary/tertiary air temperature to 1,000oC
- Drop in air requirement from 2.2 to 1.6 Nm3/ kg clinker
- Increase in cooler loading up to 50 t/d/sq m
Bypass system
Raw materials and fuels used for the manufacture of clinker generally contain some volatile constituents. These are mainly the compounds of potassium, sodium, sulphur and chlorine. Volatiles may also originate from water, refractory and wearing parts of equipment. These volatile constituents generally have low melting points. Hence, condensation of the volatile matters takes place on raw meal particles and the surrounding walls in the colder zones of the kiln. This causes build-ups on the cyclone walls and riser ducts that lead to blockages in the passage areas in the cyclones. The bypass system allows a high proportion of volatiles to be removed through the kiln gas stream and improves the performance and product quality.
Fuel solutions
Alternative fuels such as lignite, petcoke, tyres, bagasse, rice husk, industrial wastes etc, are being in use for sometime now. Several plants are using/ investigating hospital refuse and municipal waste as workable alternatives. The current reported thermal substitution rates (TSR) in the Indian cement industry is about one per cent. However, TSR levels as high as 60 per cent have been achieved in some of the developed nations. Action plans are needed to overcome technical, financial and regulatory barriers to the growth of alternate fuel (AF) usage. Technical solutions are in place for storage, handling and dosing the AF to the system.
– Kamal Kumar, Chief General Manager, Holtec
Diagnosis
Based on process measurements conducted following observations were made:
- The PH system is operating with about 28% leakage air. This is resulting in higher PH fan power consumption.
- The cooler vent gas volume of 1.63 Nm3/kg clinker and temperature of 369oC.
- High clinker temperature of 165oC value against the normal value of around 100oC.
- The heat balance of the pyro processing system indicated that the total heat consumption works out to 888 kcal/kg clinker.
| Implementations | |||||||||
| Following suggestions were implemented: | |||||||||
| Area | 2,000 t/d | ||||||||
| Kiln size | 3.95 m dia x 56 m L | ||||||||
| Preheater (PH) | Single string 5-stage suspension preheater with in line calciner (ILC) | ||||||||
| Kiln burner | Duoflex | ||||||||
| Fuel used | Furnace oil | ||||||||
| Preheater fan | 7,000 m3/min at 900 mm WG, 320oC | ||||||||
| Cooler vent fan | 5,133 m3/min at 190 mm WG, 300oC | ||||||||
| Clinker cooler | Reciprocating grate cooler | ||||||||
| Cooler effective area | 52.8 m2 | ||||||||
| No. of grates | 2 | ||||||||
| Specific heat consumption | |||||||||
| (A mass and heat balance conducted jointly) |
854 kcal/kg clinker | ||||||||
| Implementations | ||
| Following suggestions were implemented: | ||
| Area | Recommendations | Result |
| Fuel firing | Conversion of oil firing to coal firing in kiln and PC | Reduction in operation cost |
| Preheater | Reducing preheater exhaust gas quantity to 1.60 Nm3/kg clinker by arrest false air leakage, reduce the PH outlet draft | Reduction in heat consumption |
| PC primary air fan volume reduced, smaller capacity fan motor installed | Reduction in power consumption | |
| Coal transport air quantity to PC was reduced in phases | Reduction in heat consumption | |
| Maintaining PC outlet temperature as 840oC.A PID loop was provided for the PC firing. | Reduction in heat consumption | |
| Kiln | Increase the kiln speed from 3.0 to 3.3 rpm | Increased kiln output |
| Coal transport air to quantity to kiln was reduced in phases | Reduction in heat consumption | |
| Position of the inner burner pipe was retracted by 30 mm and pressure at burner pipe was increased by 10 per cent | Sharp and intense flame resulting in saving in heat consumption | |
| Clinker cooler | To reduce the cooler vent air temperature | Reduction in heat consumption. |
| Optimisation of cooler operation, commissioning of water spray system. | Reduction in clinker temperature | |
| First grate of the cooler is to be modified with the new generation static grate plates/grate systems. | Improved heat recuperation to handle increased clinker production |
|
| Stable cooler operation | ||
You may like
SEEPEX introduces BN pumps with Smart Joint Access (SJA) to improve efficiency, reliability, and inspection speed in demanding rock blasting operations.
Designed for abrasive and chemical media, the solution supports precise dosing, reduced downtime, and enhanced operational safety.
SEEPEX has introduced BN pumps with Smart Joint Access (SJA), engineered for the reliable and precise transfer of abrasive, corrosive, and chemical media in mining and construction. Designed for rock blasting, the pump features a large inspection opening for quick joint checks, a compact footprint for mobile or skid-mounted installations, and flexible drive and material options for consistent performance and uptime.

“Operators can inspect joints quickly and rely on precise pumping of shear-sensitive and abrasive emulsions,” said Magalie Levray, Global Business Development Manager Mining at SEEPEX. “This is particularly critical in rock blasting, where every borehole counts for productivity.” Industry Context
Rock blasting is essential for extracting hard rock and shaping safe excavation profiles in mining and construction. Accurate and consistent loading of explosive emulsions ensures controlled fragmentation, protects personnel, and maximizes productivity. Even minor deviations in pumping can cause delays or reduce product quality. BN pumps with SJA support routine maintenance and pre-operation checks by allowing fast verification of joint integrity, enabling more efficient operations.
Always Inspection Ready
Smart Joint Access is designed for inspection-friendly operations. The large inspection opening in the suction housing provides direct access to both joints, enabling rapid pre-operation checks while maintaining high operational reliability. Technicians can assess joint condition quickly, supporting continuous, reliable operation.
Key Features
- Compact Footprint: Fits truck-mounted mobile units, skid-mounted systems, and factory installations.
- Flexible Drive Options: Compact hydraulic drive or electric drive configurations.
- Hydraulic Efficiency: Low-displacement design reduces oil requirements and supports low total cost of ownership.
- Equal Wall Stator Design: Ensures high-pressure performance in a compact footprint.
- Material Flexibility: Stainless steel or steel housings, chrome-plated rotors, and stators in NBR, EPDM, or FKM.
Operators benefit from shorter inspection cycles, reliable dosing, seamless integration, and fast delivery through framework agreements, helping to maintain uptime in critical rock blasting processes.
Applications – Optimized for Rock Blasting
BN pumps with SJA are designed for mining, tunneling, quarrying, civil works, dam construction, and other sectors requiring precise handling of abrasive or chemical media. They provide robust performance while enabling fast, reliable inspection and maintenance.With SJA, operators can quickly access both joints without disassembly, ensuring emulsions are transferred accurately and consistently. This reduces downtime, preserves product integrity, and supports uniform dosing across multiple bore holes.
With the Smart Joint Access inspection opening, operators can quickly access and assess the condition of both joints without disassembly, enabling immediate verification of pump readiness prior to blast hole loading. This allows operators to confirm that emulsions are transferred accurately and consistently, protecting personnel, minimizing product degradation, and maintaining uniform dosing across multiple bore holes.
The combination of equal wall stator design, compact integration, flexible drives, and progressive cavity pump technology ensures continuous, reliable operation even in space-limited, high-pressure environments.
From Inspection to Operation
A leading explosives provider implemented BN pumps with SJA in open pit and underground operations. By replacing legacy pumps, inspection cycles were significantly shortened, allowing crews to complete pre-operation checks and return mobile units to productive work faster. Direct joint access through SJA enabled immediate verification, consistent emulsion dosing, and reduced downtime caused by joint-related deviations.
“The inspection opening gives immediate confidence that each joint is secure before proceeding to bore holes,” said a site technician. “It allows us to act quickly, keeping blasting schedules on track.”
Framework agreements ensured rapid pump supply and minimal downtime, supporting multi-site operations across continents
Concrete
Digital process control is transforming grinding
Published
3 weeks agoon
February 20, 2026By
admin
Satish Maheshwari, Chief Manufacturing Officer, Shree Cement, delves into how digital intelligence is transforming cement grinding into a predictive, stable, and energy-efficient operation.
Grinding sits at the heart of cement manufacturing, accounting for the largest share of electrical energy consumption. In this interview, Satish Maheshwari, Chief Manufacturing Officer, Shree Cement, explains how advanced grinding technologies, data-driven optimisation and process intelligence are transforming mill performance, reducing power consumption and supporting the industry’s decarbonisation goals.
How has the grinding process evolved in Indian cement plants to meet rising efficiency and sustainability expectations?
Over the past decade, Indian cement plants have seen a clear evolution in grinding technology, moving from conventional open-circuit ball mills to high-efficiency closed-circuit systems, Roller Press–Ball Mill combinations and Vertical Roller Mills (VRMs). This shift has been supported by advances in separator design, improved wear-resistant materials, and the growing use of digital process automation. As a result, grinding units today operate as highly controlled manufacturing systems where real-time data, process intelligence and efficient separation work together to deliver stable and predictable performance.
From a sustainability perspective, these developments directly reduce specific power consumption, improve equipment reliability and lower the carbon footprint per tonne of cement produced.
How critical is grinding optimisation in reducing specific power consumption across ball mills and VRMs?
Grinding is the largest consumer of electrical energy in a cement plant, which makes optimisation one of the most effective levers for improving energy efficiency. In ball mill systems, optimisation through correct media selection, charge design, diaphragm configuration, ventilation management and separator tuning can typically deliver power savings of 5 per cent to 8 per cent. In VRMs, fine-tuning airflow balance, grinding pressure, nozzle ring settings, and circulating load can unlock energy reductions in the range of 8 per cent to 12 per cent. Across both systems, sustained operation under stable conditions is critical. Consistency in mill loading and operating parameters improves quality control, reduces wear, and enables long-term energy efficiency, making stability a key operational KPI.
What challenges arise in maintaining consistent cement quality when using alternative raw materials and blended compositions?
The increased use of alternative raw materials and supplementary cementitious materials (SCM) introduces variability in chemistry, moisture, hardness, and loss on ignition. This variability makes it more challenging to maintain consistent fineness, particle size distribution, throughput and downstream performance parameters such as setting time, strength development and workability.
As clinker substitution levels rise, grinding precision becomes increasingly important. Even small improvements in consistency enable higher SCM utilisation without compromising cement performance.
Addressing these challenges requires stronger feed homogenisation, real-time quality monitoring and dynamic adjustment of grinding parameters so that output quality remains stable despite changing input characteristics.
How is digital process control changing the way grinding performance is optimised?
Digital process control is transforming grinding from an operator-dependent activity into a predictive, model-driven operation. Technologies such as online particle size and residue analysers, AI-based optimisation platforms, digital twins for VRMs and Roller Press systems, and advanced process control solutions are redefining how performance is managed.
At the same time, workforce roles are evolving. Operators are increasingly focused on interpreting data trends through digital dashboards and responding proactively rather than relying on manual interventions. Together, these tools improve mill stability, enable faster response to disturbances, maintain consistent fineness, and reduce specific energy consumption while minimising manual effort.
How do you see grinding technologies supporting the industry’s low-clinker and decarbonisation goals?
Modern grinding technologies are central to the industry’s decarbonisation efforts. They enable higher incorporation of SCMs such as fly ash, slag, and limestone, improve particle fineness and reactivity, and reduce overall power consumption. Efficient grinding makes it possible to maintain consistent cement quality at lower clinker factors. Every improvement in energy intensity and particle engineering directly contributes to lower CO2 emissions.
As India moves toward low-carbon construction, precision grinding will remain a foundational capability for delivering sustainable, high-performance cement aligned with national and global climate objectives.
How much potential does grinding optimisation hold for immediate energy
and cost savings?
The potential for near-term savings is substantial. Without major capital investment, most plants can achieve 5 per cent to 15 per cent power reduction through measures such as improving separator efficiency, optimising ventilation, refining media grading, and fine-tuning operating parameters.
With continued capacity expansion across India, advanced optimisation tools will help ensure that productivity gains are not matched by proportional increases in energy demand. Given current power costs, this translates into direct and measurable financial benefits, making grinding optimisation one of the fastest-payback operational initiatives available to cement manufacturers today.
Concrete
Refractory demands in our kiln have changed
Published
3 weeks agoon
February 20, 2026By
admin
Radha Singh, Senior Manager (P&Q), Shree Digvijay Cement, points out why performance, predictability and life-cycle value now matter more than routine replacement in cement kilns.
As Indian cement plants push for higher throughput, increased alternative fuel usage and tighter shutdown cycles, refractory performance in kilns and pyro-processing systems is under growing pressure. In this interview, Radha Singh, Senior Manager (P&Q), Shree Digvijay Cement, shares how refractory demands have evolved on the ground and how smarter digital monitoring is improving kiln stability, uptime and clinker quality.
How have refractory demands changed in your kiln and pyro-processing line over the last five years?
Over the last five years, refractory demands in our kiln and pyro line have changed. Earlier, the focus was mostly on standard grades and routine shutdown-based replacement. But now, because of higher production loads, more alternative fuels and raw materials (AFR) usage and greater temperature variation, the expectation from refractory has increased.
In our own case, the current kiln refractory has already completed around 1.5 years, which itself shows how much more we now rely on materials that can handle thermal shock, alkali attack and coating fluctuations. We have moved towards more stable, high-performance linings so that we don’t have to enter the kiln frequently for repairs.
Overall, the shift has been from just ‘installation and run’ to selecting refractories that give longer life, better coating behaviour and more predictable performance under tougher operating conditions.
What are the biggest refractory challenges in the preheater, calciner and cooler zones?
• Preheater: Coating instability, chloride/sulphur cycles and brick erosion.
• Calciner: AFR firing, thermal shock and alkali infiltration.
• Cooler: Severe abrasion, red-river formation and mechanical stress on linings.
Overall, the biggest challenge is maintaining lining stability under highly variable operating conditions.
How do you evaluate and select refractory partners for long-term performance?
In real plant conditions, we don’t select a refractory partner just by looking at price. First, we see their past performance in similar kilns and whether their material has actually survived our operating conditions. We also check how strong their technical support is during shutdowns, because installation quality matters as much as the material itself.
Another key point is how quickly they respond during breakdowns or hot spots. A good partner should be available on short notice. We also look at their failure analysis capability, whether they can explain why a lining failed and suggest improvements.
On top of this, we review the life they delivered in the last few campaigns, their supply reliability and their willingness to offer plant-specific custom solutions instead of generic grades. Only a partner who supports us throughout the life cycle, which includes selection, installation, monitoring and post-failure analysis, fits our long-term requirement.
Can you share a recent example where better refractory selection improved uptime or clinker quality?
Recently, we upgraded to a high-abrasion basic brick at the kiln outlet. Earlier we had frequent chipping and coating loss. With the new lining, thermal stability improved and the coating became much more stable. As a result, our shutdown interval increased and clinker quality remained more consistent. It had a direct impact on our uptime.
How is increased AFR use affecting refractory behaviour?
Increased AFR use is definitely putting more stress on the refractory. The biggest issue we see daily is the rise in chlorine, alkalis and volatiles, which directly attack the lining, especially in the calciner and kiln inlet. AFR firing is also not as stable as conventional fuel, so we face frequent temperature fluctuations, which cause more thermal shock and small cracks in the lining.
Another real problem is coating instability. Some days the coating builds too fast, other days it suddenly drops, and both conditions impact refractory life. We also notice more dust circulation and buildup inside the calciner whenever the AFR mix changes, which again increases erosion.
Because of these practical issues, we have started relying more on alkali-resistant, low-porosity and better thermal shock–resistant materials to handle the additional stress coming from AFR.
What role does digital monitoring or thermal profiling play in your refractory strategy?
Digital tools like kiln shell scanners, IR imaging and thermal profiling help us detect weakening areas much earlier. This reduces unplanned shutdowns, helps identify hotspots accurately and allows us to replace only the critical sections. Overall, our maintenance has shifted from reactive to predictive, improving lining life significantly.
How do you balance cost, durability and installation speed during refractory shutdowns?
We focus on three points:
• Material quality that suits our thermal profile and chemistry.
• Installation speed, in fast turnarounds, we prefer monolithic.
• Life-cycle cost—the cheapest material is not the most economical. We look at durability, future downtime and total cost of ownership.
This balance ensures reliable performance without unnecessary expenditure.
What refractory or pyro-processing innovations could transform Indian cement operations?
Some promising developments include:
• High-performance, low-porosity and nano-bonded refractories
• Precast modular linings to drastically reduce shutdown time
• AI-driven kiln thermal analytics
• Advanced coating management solutions
• More AFR-compatible refractory mixes
These innovations can significantly improve kiln stability, efficiency and maintenance planning across the industry.
NDMC Rolls Out Intensive Sanitation Drive Across Lutyens Delhi
UltraTech Appoints Jayant Dua As MD-Designate For 2027
Merlin Prime Spaces Acquires 13,185 Sq M Land Parcel In Pune
Adani Cement and Naredco Partner to Promote Sustainable Construction
Operational Excellence Redefined!
NDMC Rolls Out Intensive Sanitation Drive Across Lutyens Delhi
UltraTech Appoints Jayant Dua As MD-Designate For 2027
Merlin Prime Spaces Acquires 13,185 Sq M Land Parcel In Pune
Adani Cement and Naredco Partner to Promote Sustainable Construction


