Manish Samdani, Head – Quality Control, Udaipur Cement Works Limited (UCWL), shares a comprehensive view on optimising cement grinding processes and enhancing plant performance.
Can you provide an overview of the grinding process in your cement manufacturing plant and its significance in the overall production process?
In UCWL, we use the following types of mills for grinding raw materials and cement:
- Vertical Roller Mill (VRM): We employ the M/s Loesche (LM 38.4) and Gebr. Pfeiffer (MVR 6000C6) technology for raw material and cement grinding respectively. The VRM is a type of grinding mill that combines crushing, grinding, drying, and classification functions into a single compact unit. It operates by rotating a grinding table, equipped with rollers, while the raw materials are fed into the mill from the top. The rollers exert grinding pressure on the material, resulting in comminution and fine grinding. The ground material is then conveyed upwards and collected in a cyclone separator, while the coarse particles are returned to the grinding table for further grinding. The use of VRM technology allows for efficient grinding and improved energy utilisation. We are operating a mill with lowest power i.e., 12.5 KWh/MT with 10 per cent on 90 micron for raw material grinding.
- CPI and LNVT Ball Mill: CPI and LNVT is a renowned manufacturer of grinding equipment for the cement industry. Their ball mills are widely used for grinding cement clinker, gypsum, and other materials into a fine powder. The ball mill operates by rotating a horizontal cylinder, filled with steel balls, which impact and grind the material as it rotates. The ground material is discharged through the adjustable central diaphragm, while the coarse particles are returned for further grinding. CPI optimises material flow and thin linear plate, which increases the overall area of grinding also as a highly efficient dynamic separator with top feeding.
- Both the VRM and ball mill technologies provide effective grinding solutions for raw materials and cement production, each with its advantages and specific applications. The choice of the grinding mill depends on various factors such as the type of raw materials, desired fineness, production capacity, and energy efficiency requirements.
What are the main challenges you face in the grinding process, and how do you address these challenges to maintain efficiency and product quality?
At UCWL, the main challenges in the grinding process include high energy consumption, maintaining consistent product fineness, and managing moisture content in raw materials. To address these issues, UCWL uses energy-efficient VRMs, optimising parameters and employing SMARTA control systems to reduce energy usage. Consistency in product fineness is achieved through the use of online and offline PHD analysers and real-time quality control measures. Additionally, proper mixing and covered storage of raw materials help minimise moisture variations, ensuring efficient and high-quality grinding.
- Energy consumption: Grinding is an energy-intensive process, and high energy consumption can lead to increased operational costs. UCWL utilises energy-efficient grinding mills like the VRM, which consumes 23-24 kWh/MT for PPC cement compared to higher consumption in ball mills. The optimisation of grinding process parameters and the use of SMARTA advanced control systems help reduce energy usage without compromising product quality.
- Consistency in product fineness: Achieving and maintaining consistent product fineness is crucial for the quality of the final cement product. UCWL employs both online and offline PHD analysers for continuous monitoring and control of the grinding process. Advanced instrumentation and automation systems, along with real-time quality control measures, ensure the desired particle size distribution is maintained.
- Moisture content in raw materials: High moisture content in raw materials can lead to difficulties in grinding and affect the efficiency of the grinding process and quality. UCWL ensures proper mixing of raw materials and optimal storage conditions by utilising a covered storage yard, minimising variations in moisture content.
- Process and quality variability: Variability in raw material properties can lead to fluctuations in the grinding process, affecting product quality and efficiency.
We implement rigorous raw material testing and quality control procedures to ensure consistent feed quality. Real-time data is used to adjust process parameters, compensating for any variations in raw material properties. By addressing these challenges with advanced technologies, continuous monitoring, and strict quality control measures, UCWL maintains high efficiency and superior product quality in its grinding operations.
How do grinding aids contribute to the efficiency of the grinding process in your plant? What types of grinding aids do you use?
Grinding aids are chemical additives used in the cement manufacturing process to improve the efficiency and effectiveness of the grinding process. At UCWL, grinding aids play a crucial role in enhancing the performance of the grinding equipment and ensuring high-quality cement. We are using glycol-based grinding aid, which is reducing the energy required for grinding, improving one day’s strength by 2 to 3 MPa. These chemical additives lead to more efficient use of the grinding equipment, resulting in higher throughput and lower energy consumption. They also improve the flow properties of the ground material, reducing blockages and downtime. By enabling higher mill output and optimising overall mill performance, grinding aids contribute to cost savings, increased productivity, and improve product quality in the cement manufacturing process.
Can you discuss any recent innovations or improvements in grinding technology that have been implemented in your plant?
UCWL has recently implemented several innovations and improvements in grinding technology to enhance efficiency and productivity. Key among these is the integration of SMARTA and RAMCO systems for the automation of grinding systems. The SMARTA system optimises the grinding process parameters through advanced analytics and real-time monitoring, leading to significant energy savings and improved product quality. Meanwhile, the RAMCO system provides comprehensive automation, ensuring consistent control over the grinding operations and reducing the likelihood of human error. These systems enable better predictive maintenance, minimising downtime and extending the lifespan of grinding equipment. By adopting these cutting-edge technologies, UCWL has not only improved operational efficiency but also maintained high standards of product quality, positioning itself at the forefront of the cement manufacturing industry.
How do you ensure that your grinding equipment is energy-efficient and environmentally sustainable?
At UCWL, energy efficiency and environmental sustainability are achieved through several strategic measures. The use of energy-efficient equipment, such as Vertical Roller Mills (VRM), reduces energy consumption significantly compared to traditional ball mills. Advanced control systems like SMARTA and RAMCO optimise grinding parameters and provide real-time monitoring to enhance efficiency and product quality. Regular and predictive maintenance schedules ensure that equipment operates at peak performance, minimising downtime and extending lifespan. Additionally, energy management systems, including regular audits and continuous monitoring, help identify and address inefficiencies. UCWL also employs emission control technologies to minimise environmental impact, complying with regulations and promoting sustainable practices such as using alternative fuels, recycling waste products, and reducing the carbon footprint. These comprehensive efforts ensure that UCWL’s grinding operations are both energy-efficient and environmentally sustainable.
What role does R&D play in optimising your grinding processes and the selection of grinding aids?
Research and Development (R&D) at UCWL plays a pivotal role in optimising grinding processes and selecting effective grinding aids. Our R&D team focuses on process optimisation by exploring new methods to improve early strength and reduce energy consumption.
The UCWL team conducted approximately 80 to 90 R&D trials with various grinding aids to identify the most suitable formulations. These extensive trials helped in understanding the impact of different additives on grinding efficiency and product quality. Moreover, UCWL developed an in-house grinding aid, which, after successful plant-scale trials, resulted in a 2 mpa increase in initial strength and a 5 per cent increase in mill output. This in-house solution demonstrates the significant contributions of R&D in enhancing grinding performance, improving product quality, and achieving cost efficiency. Through continuous innovation and rigorous testing, R&D ensures that UCWL remains at the forefront of technological advancements in the cement industry.
Innovative technologies, such as advanced control systems, control charts and real-time monitoring tools, are developed and integrated to ensure consistent quality. Continuous improvement initiatives ensure ongoing optimisation, integrating feedback from production and quality control teams to address emerging challenges. Through these comprehensive efforts, R&D at UCWL ensures efficient, high-quality and sustainable grinding operations.
Can you share any specific examples or case studies where improvements in the grinding process have significantly benefited your plant’s performance?
The implementation of grinding aids at UCWL has led to significant improvements in the consumption of fly ash in Portland Pozzolana cement (PPC)
and a reduction in power consumption over the past four fiscal years. The data below illustrates these improvements:
Fly ash consumption (percentage):
- FY 2020-21: 25.9 per cent
- FY 2021-22: 27.7 per cent
- FY 2022-23: 30.9 per cent
- FY 2023-24: 32.5 per cent
Power consumption (kWh/MT):
- FY 2020-21: 31.2 kWh/MT
- FY 2021-22: 30.6 kWh/MT
- FY 2022-23: 28.2 kWh/MT
- FY 2023-24: 26.5 kWh/MT
By using grinding aids, UCWL has managed to increase the fly ash content in PPC from 25.9 per cent in FY 2020-21 to 32.5 per cent in FY 2023-24. This increase in fly ash usage not only improves the sustainability of the cement by utilising more industrial by-products but also enhances the overall performance of the cement. Concurrently, power consumption has decreased from 31.2 kWh/MT to 26.5 kWh/MT over the same period, demonstrating the effectiveness of grinding aids in reducing energy requirements and operational costs. These improvements highlight the critical role of grinding aids in optimising the grinding process, contributing to both economic and environmental benefits at UCWL.
What trends or advancements in grinding processes and grinding aids do you foresee impacting the cement manufacturing industry in the near future?
In the near future, the cement manufacturing industry is expected to be significantly impacted by several trends and advancements in grinding processes and grinding aids. Advanced grinding technologies, such as high-efficiency vertical roller mills (VRMs) and high-pressure grinding rolls (HPGRs), are enhancing energy efficiency and grinding performance.
Innovations in grinding aids are focusing on novel chemical additives and sustainable options that reduce energy consumption and environmental impact. Automation and digitalisation are driving improvements through real-time process optimisation and predictive maintenance, leading to better efficiency and reduced downtime.
Additionally, energy efficiency is being addressed through waste heat recovery systems and more energy-efficient equipment. The use of alternative materials and additives, along with a strong emphasis on reducing the carbon footprint, is also shaping the future of cement manufacturing. These advancements collectively aim to improve operational efficiency, lower costs and promote environmental sustainability in the industry.