Driving Decarbonisation: Advanced Fuel Substitution Technologies - presentation by Kiranmai Sanagavarapu

About 75% of the infrastructure we'll need by 2050 is yet to be built - wind turbines, climate adaptation projects, high-rise offices. On the other hand, cement, which underpins all of that infrastructure, contributes about 7% of global CO₂ emissions. This makes our industry not just part of the problem, but also an essential part of the solution.

We often get asked, "Are these technologies ready today, and which of them are still maturing?" While some solutions like alternative fuel firing and calcined clay are available today, there are other aspects like carbon capture and electrification which we are trying to crack the code for. The ready solutions include clinker substitution (30-40% emissions reduction), alternative fuels (10-15% reduction), and efficiency improvements (5-10% reduction).

Three concentric circles shape each plant's approach. Plant-level factors include operational priorities, technical constraints, and internal culture around innovation and risk. Local and regional aspects encompass fuel availability, infrastructure for processing alternative fuels, and permitting requirements. Global trends involve energy prices, supply chain unpredictability, and CO₂ policy consistency. Each plant's unique combination of these factors determines the most viable decarbonization pathway.

The ILC Low NOx Calciner achieves 80-100% alternative fuel substitution through three key design features. Large particles stay in the bottom zone with high oxygen levels, ensuring complete burnout. The system provides 20-60 seconds of particle combustion time through long gas residence times and low velocities. It handles materials up to 100x100mm and tire chips up to 50mm with minimal pre-treatment, significantly reducing fuel preparation costs.

The HOTDISC® Reactor handles materials up to 1.2 meters in size, from sludge and grains to whole truck tires. This capability matters because fuel preparation dramatically affects combustion behavior. While pulverized fuels burn in 1-10 seconds, bulky waste requires up to 1000 seconds. The Hotdisc's design accommodates this extended burnout time, turning what would be landfill waste into viable energy streams with heating values as low as 1200 kcal/kg and moisture content exceeding 50%.

We have global installations, but there is a concentration of installations in the Asian region. That is also because they sometimes tend to have poor quality alternative fuels, typically municipal sewage waste, which they would have to burn. Instead of wasting it, it's nice to burn in equipment like HOTDISC, and they're able to do that on a consistent basis. If I were to go for a HOTDISC, I would do that if I have a range of alternative fuels and a range of quality as well.

The FUELFLEX® Pyrolyzer heats refuse-derived fuel (RDF) and biomass in an oxygen-free environment, breaking materials down into combustible gases and solids through pyrolysis. This process creates a more reactive, energy-rich gas stream that burns cleaner than direct waste combustion. The technology operates as a bolt-on installation, making it particularly beneficial for small to mid-sized calciners that struggle with alternative fuel consistency.

Plant data demonstrates significant NOx reduction capabilities. When shifting solid recovered fuel from direct calciner firing to FuelFlex processing, stack NOx emissions dropped from 474 to 358 mg per normal meter cube at 10% oxygen. Simultaneously, ammonia water usage fell to zero, eliminating the need for SNCR systems. This represents tangible environmental and operational impact with measurable cost savings.

The FUELFLEX® Pyrolyzer delivers return on investment within 1-3 years, depending on local conditions including fuel costs, emission regulations, and operational requirements. For small to mid-sized calciners that struggle with alternative fuel consistency, this becomes a game changer. The technology becomes particularly attractive for plants in regions with strict ammonia usage regulations, offering an elegant solution that combines high fuel substitution, NOx reduction, and minimal fossil fuel consumption in a single bolt-on package.

Our comprehensive automation portfolio includes process control and optimization through ECS/ControlCenter and ProcessExpert software, sampling preparation and analysis via QCX/BlendExpert and RoboLab systems, and gas analysis through KilnLoq and GASLoq systems. These solutions ensure fuel substitution doesn't compromise quality or throughput while maintaining compliance with environmental regulations and optimizing combustion efficiency.

No silver bullet exists in decarbonization. Success requires combining the right technologies for each plant's specific context. Optimal fuel substitution demands integration of alternative fuel storage and dosing systems, precise coal dosing where needed, advanced process control, high-performance burners like JETFLEX®, and bypass solutions for managing elements like chlorine. Each component plays a critical role in the overall system performance.

The green transition is a continuous journey, not a one-time event. Plants should start now, learn quickly, and build incrementally. Every plant, regardless of size or location, can take meaningful steps today by understanding their specific circles of influence and selecting appropriate technology combinations. The key is beginning the transition process immediately while maintaining operational stability and economic viability.

Yes, this trend is accelerating. Customer conversations increasingly include technologies like the HOTDSIC and FUELFLEX as part of initial business cases rather than afterthoughts. This development is inspiring because it indicates plants have figured out what works, established alternative fuel supply chains, and anticipated various operational scenarios. Modern kiln designs increasingly incorporate high alternative fuel utilization from the planning stage.

The choice depends on available fuel types and market maturity. The HOTDSIC works best with diverse, varying-quality alternative fuels including very low-grade materials. The FUELFLEX® Pyrolyzer suits plants with access to engineered fuels—pre-shredded materials from more mature waste processing markets like the US and Europe. The FUELFLEX is particularly valuable as a retrofit solution for space-constrained facilities or smaller calciners struggling with fuel consistency.

The industry continues advancing multiple technology fronts simultaneously. While alternative fuel technologies and calcined clay substitution deliver immediate results, carbon capture and electrification solutions are progressing toward commercial viability. Future success will depend on continued innovation in automation, process control, and integrated system approaches that combine multiple decarbonization levers. The emphasis remains on proven, scalable solutions that deliver measurable environmental and economic benefits.