Concrete
Design for Solid Alternative Fuels
Published
8 months agoon
By
adminKapil Kukreja, Group Manager; Dr D K Panda, Joint Director; and Bharat Bhushan, Project Engineer, National Council for Cement and Building Materials (NCB), Ballabgarh, India, present their findings in an article that delves into the methodology used to tackle the identified issue and discusses the R&D project taken up by NCB that resulted in the creation of an innovative design capable of effectively managing diverse alternative fuels and their combinations.
At COP26, India made a significant commitment by pledging to embrace a low-carbon growth path and to shift half of its energy consumption away from fossil fuels and towards non-fossil alternatives by the close of this decade. Moreover, India has set the ambitious goal of achieving carbon neutrality by the year 2070. To achieve the target of carbon neutrality, alternative fuels (AFs), including biomass, refuse-derived fuel (RDF), used tires, plastic waste and hazardous waste, which have the potential to replace conventional fossil fuels such as coal, pet coke, etc. These AF are seen as promising solutions in line with India’s mission to reach carbon neutrality.
Nonetheless, with the adoption of these AF, challenges were encountered in handling of AF and their mix, encompassing environmental, product quality, logistical issues, health and safety concerns, as well as the intricacies of the processes and operations involved. However, one of the main challenges faced while handling AF used in cement plants is the jamming of the transfer chute.
Chute transfers are vital for material handling but can often become weak links in the chain. These components are used in conveying systems to transfer bulk materials between feeders, screens, and from one conveyor to another or for discharge into burners/pre-calciner. Chute design requires careful attention, as handling AFs with variations in material characteristics or operational requirements can lead to productivity losses and operational disruptions due to jamming or unpredictable chute behaviour.
Problem with chutes
A survey was conducted in the Indian cement industry in the year of 2019-20 to assess the issues related with handling of AFs and their mix. Out of 100 questionnaires distributed, 61 responses were received, providing valuable insights. The survey highlighted that 78.7 per cent of respondents faced transfer chute issues when handling AFs, primarily jamming. The main reasons included using conventional chute designs unsuitable for heterogeneous AFs,
lack of knowledge about material flow and properties, and the unexpected introduction of new materials not considered during chute design. These issues led to significant maintenance efforts and operational disruptions.
One significant cause of chute jamming is the reliance on traditional chute design methods, which have been widely employed in the Indian cement industry for handling uniform materials like limestone, coal, bauxite, and iron ore. These methods fall short when dealing with heterogeneous AFs due to the varying properties of these materials throughout the year, depending on their source, mix content, and other factors. Additionally, a lack of understanding of material flow and physical properties, such as shape, size, angle of repose and angle of inclination, contributes to chute issues.
Another key factor identified in the survey is the unexpected introduction of new materials that were not considered during chute design. Anticipating all potential AF types during design is challenging because cement plants select materials based on factors like cost, suitability for their raw mix, fossil fuel prices, and availability. Therefore, it was challenge to design a transfer chute which can handle various AF and their mix without any jamming issues.
Solution
Based on the survey result, NCB took the problem related to jamming of transfer chute while utilising AFs and their mix in Indian Cement Industry as an R&D project. The project commenced with the site visit of cement plants, discussion with plant personnel and determination of material properties, providing essential foundational data. Utilising this data, key input parameters were carefully selected to run the Discrete Element Modelling (DEM) simulations.
To ensure the DEM model’s accuracy, it underwent calibration through the development of CAD calibration models. These models aligned the DEM model with real-world conditions. Following calibration, the existing transfer chute design was simulated using DEM. Accordingly, 14 simulations of AFs were conducted using the DEM, and the subsequent outcomes were thoroughly examined to pinpoint significant concerns associated with the traditional chute design. This analysis served as the basis for developing an improved transfer
chute model. The enhanced design was subsequently subjected to DEM simulation to assess its
performance. The various designs were evaluated and necessary modifications were made to address any identified issues to improve the performance of the transfer chute.
Fig 1: Simulation Results for Industrial Waste
Additionally, adjustments to the DEM parameters were carried out to fine-tune the model’s accuracy. The ultimate goal of this comprehensive process was to arrive at the final design of a transfer chute suitable for handling AF and their mix without jamming. The final parameters obtained after fine tuning and making adjustment to the chute design in simulation are as follows:
• Chute Valley Angle: 70°
• Chute Width (Minimum): 4.3 to 4.5 times the lump size
• Chute Hood Height at the material entrance: Minimum 0.6 times the Belt Width
• Cross-sectional area of transfer chute: Minimum 10 to 11 times of cross-sectional area of the material stream inside the chute.
• Selected Liners: UHMWPE
Based on the above parameters obtained after simulation, an experimental setup comprising four transfer chutes and belt conveyors was established on NCB’s Ballabgarh premises to conduct experimental study on the different samples of AF collected from different cement plants and sites. Thereafter, 19 AF and their mix were collected from different cement plants across India. The materials were experimented on different mass flow rates of 3, 5, 8, 10 and 15 tph and with moisture content levels spanning from 0.18 to 45 per cent. Remarkably, even after a total of 261 hours of operation on the experimental setup, no instances of jamming were observed in the transfer chute.
Even when faced with a jamming scenario, the innovative flexible arrangement introduced in the transfer chute design (patent filed by NCB) proven to be highly effective at swiftly addressing blockages caused by solid AF. It helps in clearing these blockages in just six minutes, representing a significant improvement compared to the conventional method, which typically necessitates a lengthy 85 to 105 minutes to remove and resume operations. This innovative approach optimises the chute cleaning process, ensuring uninterrupted operations.
Figures 2, 3 and 4 shows the general arrangement of the of the experimental setup and glimpses of experiments:
Conclusion
In the cement industry, conventional transfer chute designs have posed challenges when handling a range of diverse alternative fuels. To address this issue, a new transfer chute design capable of handling various AFs and their mixtures has been developed by the NCB. This innovative design can handle various AFs and their mixes and also significantly reduces chute jamming and cleaning time to 6-8 minutes. The NCB led the development of this versatile transfer chute design, which promises to enhance material handling in cement plants. The project’s outcomes led by NCB are valuable for system design improvements and process optimisation, streamlining cement plant operations.
ABOUT THE AUTHOR:
Dr Kapil Kukreja, Group Manager (CME), NCB has over 19 years of work experience in the field of System Design, Project Engineering and Management. He has previously worked with organisations like ACC, Holtec Consulting, JK White Cement etc.
Bharat Bhushan, Project Engineer (CME), NCB has a one-year experience as Project Engineer in the field of System Design, Project Engineering & Management.
Dr Dhirendra Kumar Panda, Joint Director, NCB has over 36 years of experience in the areas of Geology, Raw Materials and Mining and administrative experience as a Team Leader, Programme Leader and Head of the Centre.
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Concrete
Indian Cement Industry Sees Further Consolidation
Cement industry to face consolidation soon.
Published
2 days agoon
September 13, 2024By
adminIndia’s cement sector is set for further consolidation in the near-to-medium term, according to a recent report. With increasing competition, rising input costs, and the need for economies of scale, companies are expected to explore mergers and acquisitions (M&A) to strengthen their market positions. As the industry faces various challenges, including high energy costs and fluctuating demand, consolidation is viewed as a strategic move to drive growth and sustainability.
Key Points:
Market Consolidation: The Indian cement industry has already witnessed significant consolidation over the past few years, with several large firms acquiring smaller players to enhance their market share. The trend is expected to continue, driven by the need to optimize operations, cut costs, and gain better pricing power. Consolidation helps companies to expand their geographic reach and strengthen their portfolios.
Rising Costs and Challenges: One of the primary drivers of consolidation is the rising cost of inputs, particularly energy and raw materials. With costs of coal and petroleum coke (key energy sources for cement production) soaring, companies are looking for ways to maintain profitability. Smaller and medium-sized players, in particular, find it challenging to cope with these rising costs, making them more likely targets for acquisition by larger companies.
Economies of Scale: Larger cement companies benefit from economies of scale, which help them absorb the impact of rising input costs more effectively. Consolidation allows firms to streamline production processes, reduce operational inefficiencies, and invest in advanced technologies that improve productivity. These efficiencies become critical in maintaining competitiveness in an increasingly challenging environment.
M&A Activity: The report highlights the potential for more mergers and acquisitions in the cement sector, particularly among mid-sized and regional players. The Indian cement market, which is highly fragmented, presents numerous opportunities for larger companies to acquire smaller firms and gain a foothold in new markets. M&A activity is expected to accelerate as firms seek growth through strategic alliances and acquisitions.
Regional Focus: Consolidation efforts are likely to be regionally focused, with companies looking to expand their presence in specific geographic areas where demand for cement is strong. Infrastructure development, government projects, and urbanization are driving demand in various parts of the country, making regional expansions an attractive proposition for firms looking to grow.
Impact on Competition: While consolidation may lead to a more concentrated market, it could also intensify competition among the remaining players. Larger firms with more resources and market reach could dominate pricing strategies and influence market dynamics. Smaller firms may either merge or struggle to compete, leading to a reshaping of the competitive landscape.
Demand Outlook: The near-term outlook for the cement industry remains uncertain, with demand being influenced by factors such as construction activity, infrastructure projects, and government initiatives. The report notes that while urban demand is expected to remain stable, rural demand continues to face challenges due to slow construction activities in those areas. However, the long-term outlook remains positive, driven by ongoing infrastructure developments and real estate projects.
Sustainability Focus: Companies are also focusing on sustainability and environmental concerns. Consolidation can provide larger companies with the resources to invest in green technologies and reduce their carbon footprint. This focus on sustainability is becoming increasingly important, with both government regulations and market preferences shifting toward greener production practices.
Conclusion:
The Indian cement industry is poised for further consolidation in the coming years, driven by rising costs, competitive pressures, and the need for economies of scale. M&A activity is likely to accelerate, with larger firms targeting smaller and regional players to strengthen their market presence. While consolidation offers opportunities for growth and efficiency, it could also reshape the competitive landscape and influence pricing dynamics in the sector.
Concrete
Cement Companies May Roll Back Hike
Cement firms reconsider September price increase.
Published
2 days agoon
September 13, 2024By
adminCement companies in India might be forced to reverse the price hikes implemented in September due to weakened demand and pressure from competitive market conditions, according to a report by Nuvama Institutional Equities. The recent price increase, which was expected to improve margins, may not hold as demand falls short of expectations.
Key Points:
Price Hike in September: Cement firms across India increased prices in September, aiming to improve their margins amidst rising input costs. This was seen as a strategic move to stabilize earnings as they were grappling with inflationary pressures on raw materials like coal and pet coke.
Weak Demand and Pressure: However, demand has not surged as expected. In some regions, particularly rural areas, construction activity remains low, which has contributed to the tepid demand for cement. The combination of high prices and low demand may make it difficult for companies to maintain the elevated price levels.
Competitive Market Forces: Cement manufacturers are also under pressure from competitors. Smaller players may keep prices lower to attract buyers, forcing larger companies to consider rolling back the September hikes. The competitive dynamics in regions like South India, where smaller firms are prevalent, are likely to impact larger companies’ pricing strategies.
Nuvama Report Insights: Nuvama Institutional Equities has highlighted that the September price hikes may not be sustainable given current market conditions. According to the report, the demand-supply imbalance and weak construction activities across many states could push cement companies to reconsider their pricing strategies.
Impact on Margins: If companies are compelled to roll back the price hikes, it could hurt their profit margins in the near term. Cement firms had hoped to recover some of their input costs through the price increases, but the competitive landscape and slow demand recovery could negate these gains.
Regional Variations: Price rollback might not be uniform across the country. In regions where infrastructure development is picking up pace, cement prices may hold. Urban areas with ongoing real estate projects and government infrastructure initiatives could see a sustained demand, making price hikes more viable.
Future Outlook: The outlook for the cement sector will largely depend on the pace of recovery in construction activity, particularly in the housing and infrastructure sectors. Any significant recovery in rural demand, which is currently subdued, could also influence whether the price hikes will remain or be rolled back.
Strategic Adjustments: Cement firms may need to adopt a cautious approach in the near term, balancing between maintaining market share and protecting margins. Price adjustments in response to market conditions could become more frequent as companies try to adapt to the fluctuating demand.
Conclusion:
The September price hikes by cement companies may face reversal due to weak demand, competitive pressures, and market dynamics. Nuvama’s report signals that while the increase was aimed at margin recovery, it may not be sustainable, particularly in regions with low demand. The future of cement pricing will depend on construction sector recovery and regional market conditions.
Concrete
Bridge Collapse Spurs Focus on Stainless Steel
Climate change prompts stainless steel push.
Published
2 days agoon
September 13, 2024By
adminThe Ministry of Road Transport and Highways (MoRTH) is turning its attention to the use of stainless steel in bridge construction to counteract corrosion, an increasing issue linked to climate change. With recent bridge collapses highlighting the vulnerability of existing infrastructure to corrosion and extreme weather events, the ministry is promoting the adoption of durable materials like stainless steel to ensure the longevity and safety of India’s critical transport infrastructure.
Key Points:
Bridge Collapse and Climate Change: Recent incidents of bridge collapses across the country have raised alarm over the durability of current construction materials, with corrosion cited as a leading cause. Climate change, leading to harsher weather patterns and increased moisture levels, has accelerated the deterioration of key infrastructure. This has prompted MoRTH to consider long-term solutions to combat these challenges.
Corrosion: A Growing Concern: Corrosion of structural materials has become a serious issue, particularly in coastal and high-moisture regions. The Ministry has identified the need for a more resilient approach, emphasizing the use of stainless steel, known for its resistance to corrosion. This shift is seen as crucial in ensuring the longevity of India’s bridges and reducing maintenance costs over time.
Stainless Steel for Bridge Construction: Stainless steel, while more expensive initially, offers long-term savings due to its durability and resistance to environmental factors like moisture and salt. The Ministry is advocating for the material’s use in future bridge projects, particularly in areas prone to corrosion. Stainless steel is seen as a solution that can withstand the pressures of both natural elements and increasing traffic loads.
Government’s Proactive Steps: The government, through MoRTH, has started consulting with experts in the field of metallurgy and civil engineering to explore the expanded use of stainless steel. They are considering updates to construction standards and specifications to incorporate this material in new and rehabilitated infrastructure projects.
Economic Considerations: Although the initial investment in stainless steel may be higher than conventional materials, the reduced need for repairs and replacements makes it a cost-effective option in the long run. This approach also aligns with the government’s push for sustainable infrastructure that can withstand the test of time and climate change effects.
Future of Indian Infrastructure: With the push for stronger, more durable infrastructure, the Ministry’s move to adopt stainless steel for bridge construction marks a shift towards building climate-resilient structures. The use of this material is expected to not only enhance the safety and longevity of bridges but also reduce the financial burden on the government for constant repairs.
Industry Perspective: The stainless steel industry sees this shift as an opportunity to expand its market, particularly in the infrastructure sector. Stakeholders are engaging with the government to demonstrate the benefits of stainless steel, advocating for its increased use not just in bridges but across various infrastructure projects.
Conclusion: In response to the growing threat of climate change and its impact on infrastructure, the Ministry of Road Transport and Highways is prioritizing the use of stainless steel in bridge construction to combat corrosion and ensure the long-term durability of critical transport structures.