Economy & Market

When Ash Sticks, Everything Stops

Published

5 months ago

November 20, 2025

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Jigar Shah, Head – Application Engineering, ACM SBU, Henkel Adhesive Technologies India, looks at the smarter way to keep power flowing.

In cement manufacturing, where uptime is everything, captive power plants are the backbone of uninterrupted operations. But even the most robust systems can be brought to a halt by something as deceptively simple as ash.
Ash buildup—especially in high-humidity environments—is a recurring challenge for maintenance teams. It clings to the inner walls of hoppers and silos, chokes flow paths, and forces shutdowns that no one has time for. And when the monsoon rolls in, the problem only intensifies.
This is the story of how one thermal power plant in India tackled the issue—not with more manpower or heavier hammers, but with a surface engineering solution developed by Henkel’s Loctite team. The application of Loctite® PC 7337 Anti-Stick Coating helped the plant shift from reactive maintenance to preventive control, restoring flow and reliability where it mattered most.

The sticky truth
Ash is an inevitable by-product of coal combustion. In captive power plants, fly ash is collected in electrostatic precipitators (ESPs) and directed to ash hoppers. Bottom ash, meanwhile, is sluiced with water into Hydrobin tanks—large cylindrical silos where solids settle and water is drained off for further treatment.
In theory, it’s a straightforward process. In practice, it’s anything but.
Ash particles are fine, abrasive and hygroscopic. They absorb moisture from the air, especially during the rainy season, and form stubborn layers on metal surfaces. Over time, this buildup narrows flow paths, increases system pressure, and eventually brings operations to a standstill.
At the plant in question, maintenance teams were routinely forced to shut down operations to manually clear out ash deposits. Sometimes that meant hammering on hopper walls. Other times, it meant full system stoppages. Either way, the cost—in time, labour and lost production—was significant.

A new approach
Rather than redesign the system or increase maintenance frequency, the plant’s engineering team explored a different path: surface modification.
They partnered with Henkel’s Application Engineering team to trial Loctite® PC 7337—a polymer-based anti-stick coating designed specifically for abrasive, high-moisture environments. The goal was simple: prevent ash from sticking in the first place.
Loctite PC 7337 was applied to the internal surfaces of the Hydrobin tank and ash hopper. The coating offered a low-friction, hydrophobic barrier that repelled fine particles and resisted wear. But as with any industrial solution, success depended on proper preparation and execution.

Application in action
The coating process followed a meticulous five-step protocol:
1. Surface preparation: Initial cleaning involved the removal of oil, grease and other contaminants. Abrasive blasting followed, creating a surface profile of 40–60 microns to ensure strong mechanical bonding.
2. Dust removal: All residual dust was cleared to prevent contamination and ensure a clean substrate.
3. Coating application: Loctite PC 7337 was mixed and applied to a wet film thickness of 200–250 microns. No heat curing was required—ambient conditions were sufficient.
4. Curing: The coating was left to cure for 24 hours, forming a durable, glossy finish.
5. Inspection: Final checks included dry film thickness measurement, visual inspection and holiday detection to confirm coating integrity.
The result? A smooth, frictionless surface that ash simply couldn’t cling to.

Real-world results
Post-application, the plant saw immediate improvements. Ash no longer adhered to the coated surfaces, even during peak humidity. Flow paths remained clear, and the need for manual cleaning dropped dramatically.
Here’s what changed:
• Fewer shutdowns: With ash buildup under control, unplanned stoppages became a thing of the past.
• Improved flow efficiency: Material moved more freely through the system, reducing pressure fluctuations and wear.
• Regulatory compliance: The plant was able to meet its monthly ash disposal targets, aligning with environmental mandates from the National Green Tribunal (NGT).
• Cost savings: Reduced maintenance and downtime translated into measurable financial benefits.

Why it worked
The coating’s performance came down to two key properties: abrasion resistance and hydrophobicity.
In lab tests, Loctite PC 7337 showed excellent wear resistance, losing only 9 mg after 1000 cycles under a 1 kg load using CS-17 wheels (ASTM D4060). That’s critical when dealing with fine, abrasive particles like fly ash and clinker dust.
Equally important was its ability to repel moisture. The coating’s low surface energy and high contact angle created a hydrophobic barrier that prevented wet ash from bonding to the surface—a common failure point for traditional coatings.
It also proved effective across a wide range of particle sizes. From cement fines under 45 microns to pulverized coal (79–120 microns) and clinker dust (3–30 microns), Loctite PC 7337 maintained its anti-stick properties. Even particles up to 1 mm showed only moderate adhesion during internal trials.

Beyond power plants
While this case focused on a thermal power plant, the implications for cement manufacturing are clear. Many of the same challenges—fine particle buildup, moisture-induced sticking, and flow disruptions—occur throughout the plant.
Potential applications for Loctite PC 7337 include:
• ID fan coatings: To prevent dust accumulation and maintain airflow efficiency.
• Pump linings: To reduce wear and improve slurry flow in wet handling systems.
• Silo and hopper interiors: To prevent bridging and rat-holing in cement and fly ash storage.
• Chutes and ducts: To enhance flow and reduce maintenance in pneumatic conveying systems.
By proactively addressing surface behaviour, cement plants can reduce maintenance burdens, extend equipment life, and improve process reliability.

A shift in mindset
This project highlights a broader shift in industrial maintenance philosophy—from reactive fixes to preventive strategies. Instead of waiting for problems to arise, forward-thinking plants are investing in solutions that stop issues before they start.
Surface engineering, particularly with advanced coatings like Loctite PC 7337, is a powerful tool in this shift. It allows operators to tailor equipment surfaces to their specific material and environmental challenges, rather than relying on generic designs or brute-force maintenance.
And while the coating itself was a key enabler, the real success came from collaboration. The plant’s willingness to try a new approach, combined with the technical support of Henkel’s Loctite team, created a solution that was both practical and scalable.

Small change, big impact
Sometimes, the biggest operational wins come from the smallest changes. In this case, a 250-micron of Loctite PC 7337 made the difference between constant maintenance and consistent performance.
For cement plants navigating the complex demands of energy efficiency, environmental compliance, and cost control, solutions like these offer a compelling path forward. They’re not flashy. They don’t require massive capital investment. But they work—and they work where it counts.
Because when ash sticks, everything stops. And when it doesn’t, everything flows.

ABOUT THE AUTHOR:
Jigar Shah, Head – Application Engineering, ACM SBU, Henkel Adhesive Technologies India, has 20+ years of experience. He drives efficiency and sustainability through innovations.

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TSR Will Define Which Cement Companies Win India’s Net-Zero Race

Published

3 days ago

April 27, 2026

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Jignesh Kundaria, Director and CEO, Fornnax Technology

India is simultaneously grappling with two crises: a mounting waste emergency and an urgent need to decarbonise its most carbon-intensive industries. The cement sector, the second-largest in the world and the backbone of the nation’s infrastructure ambitions, sits at the centre of both. It consumes enormous quantities of fossil fuel, and it has the technical capacity to consume something else entirely: the waste our cities cannot get rid of.

According to CPCB and NITI Aayog projections, India generates approximately 62.4 million tonnes of municipal solid waste annually, with that figure expected to reach 165 million tonnes by 2030. Much of this waste is energy-rich and non-recyclable. At the same time, cement kilns operate at material temperatures of approximately 1,450 degrees Celsius, with gas temperatures reaching 2,000 degrees. This high-temperature environment is ideal for co-processing, ensuring the complete thermal destruction of organic compounds without generating toxic residues. The physics are in our favour. The infrastructure is not.

Pre-processing is not the support act for co-processing. It is the main event. Get the particle size wrong, get the moisture wrong, get the calorific value wrong and your kiln thermal stability will suffer the consequences.

The Regulatory Push Is Real

The Solid Waste Management (SWM) Rules 2026 mandate that cement plants progressively replace solid fossil fuels with Refuse-Derived Fuel (RDF), starting at a 5 per cent baseline and scaling to 15 per cent within six years. NITI Aayog’s 2026 Roadmap for Cement Sector Decarbonisation targets 20 to 25 per cent Thermal Substitution Rate (TSR) by 2030. Beyond compliance, every tonne of coal replaced by RDF generates measurable carbon reductions which is monetisable under India’s emerging Carbon Credit Trading Scheme (CCTS). TSR is no longer a sustainability metric. It is a financial lever.

Yet our own field assessments across multiple Indian cement plants reveal a sobering reality: the primary barrier to scaling AFR adoption is not waste availability. It is the fragmented and under-engineered pre-processing ecosystem that sits between the waste and the kiln.

Why Indian Waste Is a Different Engineering Problem

Indian municipal solid waste is not the material that imported shredding equipment was designed for. Our waste streams frequently exceed 40 per cent to 50 per cent moisture content, particularly during monsoon cycles, saturated with abrasive inerts including sand, glass, and stone. Plants relying on imported OEM equipment face months of downtime awaiting proprietary spare parts. Machines built for segregated, low-moisture waste fail quickly and disrupt the entire pre-processing operation in Indian conditions.

The two most common failures we observe are what I call the biting teeth problem and the chewing teeth problem. Plants relying solely on a primary shredder reduce bulk waste to large fractions, but the output remains too coarse for stable kiln combustion. Others attempt to use a secondary shredder as a standalone unit without a primary stage to pre-size the feed, leading to catastrophic mechanical failure. When both stages are present but mismatched in throughput capacity, the system becomes a bottleneck. Achieving the 40 to 70 tonnes per hour required for meaningful coal displacement demands a precisely coordinated two-stage process.

Engineering a Made-in-India Answer

At Fornnax, our response to these challenges is grounded in one principle: Indian waste demands Indian engineering. Our systems are built around feedstock homogeneity, the holy grail of kiln stability. Consistent particle size and predictable calorific value are the foundation of stable kiln combustion. Without them, no TSR target is achievable at scale.

Our SR-MAX2500 Dual Shaft Primary Shredder (Hydraulic Drive) processes raw, baled, or loosely mixed MSW, C&I waste, bulky waste, and plastics, reducing them to approximately 150 mm fractions at throughputs of up to 40 tonnes per hour. The R-MAX 3300 Single Shaft Secondary Shredder (Hydraulic Drive), introduced in 2025, takes that primary output and produces RDF fractions in the 30 to 80 mm range at up to 30 tonnes per hour, specifically optimised for consistent kiln feeding. We have also introduced electric drive configurations under the SR-100 HD series, with capacities between 5 and 40 tonnes per hour, already operational at a leading Indian waste-processing facility.

Looking ahead, Fornnax is expanding its portfolio with the upcoming SR-MAX3600 Hydraulic Drive primary shredder at up to 70 tonnes per hour and the R-MAX2100 Hydraulic drive secondary shredder at up to 20 tonnes per hour, designed specifically for the large-scale throughput that higher TSR ambitions require.

The Investment Case Is Now

The 2070 Net-Zero target is not a distant goal for India’s cement sector. It starts today, with decisions being made on the plant floor.

The SWM Rules 2026 are already in effect, requiring cement plants to replace coal with RDF. Carbon credit markets are opening up, and coal prices are not going to get cheaper. Every tonne of coal a cement plant replaces with waste-derived fuel saves money on one side and generates carbon credit revenue on the other. Pre-processing infrastructure is no longer just a compliance requirement. It is a business investment with a measurable return.

The good news is that nothing is missing. The technology works. The waste is available in every Indian city. The government has provided the policy direction. The only thing standing between where the industry is today and where it needs to be is the commitment to build the right infrastructure.

The cement companies that move now will not just meet the regulations. They will be ahead of every competitor that waits.

About The Author

Jignesh Kundaria is the Director and CEO of Fornnax Technology. Over an experience spanning more than two decades in the recycling industry, he has established himself as one of India’s foremost voices on waste-to-fuel technology and alternative fuel infrastructure.

Concrete

WCA Welcomes SiloConnect as associate corporate member

Published

2 weeks ago

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The World Cement Association (WCA) has announced SiloConnect as its newest associate corporate member, expanding its network of technology providers supporting digitalisation in the cement industry. SiloConnect offers smart sensor technology that provides real-time visibility of cement inventory levels at customer silos, enabling producers to monitor stock remotely and plan deliveries more efficiently. The solution helps companies move from reactive to proactive logistics, improving delivery planning, operational efficiency and safety by reducing manual inspections. The technology is already used by major cement producers such as Holcim, Cemex and Heidelberg Materials and is deployed across more than 30 countries worldwide.

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TotalEnergies and Holcim Launch Floating Solar Plant in Belgium

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