Technology
Selecting Boiler Technology for Multi-Fuel Firing
Published
12 years agoon
By
admin
In the recent past the power sector, including the captive power generation segment, has seen many changes at policy levels, in options for sale and purchase of power, technological changes, business models and above all in issues related to fuel availability.
Fuel availability stands out as one of the biggest challenges for an energy intensive industry. With weak or expensive grid, most of the energy intensive industries had to resort to captive power generation. However, with recent volatility in fuel supply and costs, industrial investors had to look at multi-fuel options.
Associated Risks
As an investor, who is looking at investment in a mid sized power project, he has to look at the risks he carries, safeguards to put in place to mitigate them. The investor is stumped with the plethora of options at each stage, be it:
Development risks, including:
- Statutory clearances
- Linkages
- Financial closure
- Land and rehabilitation
Construction risks, like:
- Schedules
- Cash flow
- IDC
- Quality
Technical risks, including:
- Technology
- Developer/contractor?s competence and experience
Commercial risks
- Feasibility
- Project schedule
- Contractor?s financial strength
Operations and maintenance related risk
- Heat rate guarantees
- Manpower cost
- Plant performance
- And last but not the least, marketing and revenue related risk.
For a power project to succeed, an investor looks at the financial viability of the project. Two foremost factors on the investor?s mind are the project cost and the operating cost. Project cost comprise of capital cost, interest cost and the development cost. The second most important parameter being the operating cost of the power plant, which will enable him to forecast the cash flow. In a power plant the main operating costs being station heat rate, manpower cost and the cost of consumables.
The investor is concerned about the return on his investments, which come from the basic technical feasibility of the project and the technology being utilised. His return on investment also depends on the guarantees that he can get on the project cost and how well he can estimate and mitigate the variations. The performance guarantees are far more important than the project cost guarantees. Performance variations can bleed income from the project for its lifetime, which is typically about 20-25 years. The IDC and the returns starting to accrue come from the guarantee of the schedule he sets for the project and how it is adhered to. Generally, based on all these parameters and risk taking abilities of the investor and his bankers, the decision is taken whether to go ahead with the project on a packaged route of to pass the risk to a reputed EPC contractor.
An EPC contractor takes the entire risk of construction upon himself. If the EPC contractor is also a technology provider like a boiler manufacturer in the case of power plant, then even the technological risk is totally on to him. If the EPC contractor is ready to undertake long term operations and maintenance of the power project then the O&M risks is also passed on to him, leaving only the development risk and part of commercial risk in the developer and banker?s scope. The commercial risk can be further diluted with a financially sound EPC contractor and having watertight contract in place, leaving only the development risk in investor?s scope.
Role of Technology
In today?s context of fuel uncertainty, technology plays a vital role especially regarding boiler choice. One has to look at aspects like:
Boiler technology
Suitability of various kinds of fuels
Boiler pressure and temperature
Fuel firing limitations
Boiler efficiency and availability
Physical characteristics
Physical characteristics of the fuel should also be accounted for in the designing process. This is extremely important, in case biomass is being considered as a main or supplementary fuel. Physical characters include size, bulk density, flowability.
Chemical characteristics
Chemical constituents such as chlorine (elemental chlorine and not chlorides in ash) as chlorine in biomass can cause corrosion problems. So these factors must also be considered while designing the system. Alkali content (Na2O+K2O) in fuel leads to problems like slagging and fouling.
Boiler efficiency depends on moisture content in the fuel. Combustion efficiency depends on ash content and excess air. High excess air increases combustion efficiency however it also increases dry flue gas losses. NOx generation is a function of temperature, staging of air and excess air percentage.
If moisture content in fuel is high, in bed tubes can be avoided. In case most fuels being considered are solid fuels like mix of different types of coal, lignite or petcoke the options on technology can be a little easier.
Circulating Fluidised Bed Combustion Technology
Uncertainty regarding availability and reliability of single fuel type, stringent emission norms, constraints of firing multiple type of fuels in pulverised coal fired boilers and need of additional capital intensive accessories like coal mill, FGD, etc. led to development of Circulating Fluidised Bed Combustion Technology (CFBC) design. CFBC technology in today?s time of high fuel uncertainty and volatility can be considered as a boon to power and process industry requiring power and process steam.
CFBC is a fuel flexible technology, which can handle variation in GCV from 1800- 8000 kcal/kg, ash 5-65 per cent and moisture from 1-45 per cent. The turbulent bed, which is operating at 4-5.5 m/s, is able to enhance the fuel burn ability by rapid mixing of fuel with hot bed material resulting in efficient carbon burnout.
The CFBC technology has versions that have wider multi-fuel firing capability including:
Coal:
-
Anthracite, bituminous, sub-bituminous, lignite (Neyveli/Kutch/Barmer) and high-sulphur coal.
Waste Coal:
-
Washery rejects, char.
Petroleum coke (petcoke):
-
Delayed, fluid.
Other renewable fuels:
-
Sludge, oil pitches, biomass, agro-wastes and refuse derived fuel.
The new generation IRCFBC technology can easily cater to fuel with:
- Moisture content up to 60 per cent, e.g., in lignite, peat, sludge
- Ash up to 76 per cent, e.g., in washery rejects, char.
- Sulphur up to 8 per cent, e.g., in lignite, petcoke.
- Volatiles, as low as 1 per cent as in petcoke, washery rejects, char, etc.
- HHV as low as 1500 Kcal/kg as found in washery rejects, char, etc.
Factors to be considered while choosing boiler technology
Here is a list of few important factors that must be considered while choosing boiler technology.
Compact, economical design and construction
If the boiler technology design has lower furnace exit gas velocity and requires significantly less building volume, say by relying on internal recirculation, the design can eliminate J-valves, loop seals, high-pressure blowers, and soot blowers, which makes the boiler compact and economical on lifetime costs.
Separation in stages for better bed inventory control
If the design has optimal stage wise particle separation system, it will help to provide high-solids loading and a uniform furnace temperature profile. The benefits of this include superior combustion efficiency, high operational thermal efficiency, low emissions, low maintenance, low pressure drop, and high turndown, resulting in improved overall plant performance and particle collection efficiency as high as 99.8 per cent for better inventory control. The separation technology must be of fit and forget type.
Performance in varying and low load conditions
With effective bed inventory and temperature control through controlled solid recycle rate from MDC to furnace you get better performance and operation of boiler. Turn down ratios as high as 1:5 can easily be achieved in some designs.
Start up and shut down time
Some designs have much lower refractory heat retention as compared to other CFBC designs. This allows quick start and shut down of the boiler.
Auxiliary consumption
Boiler designs with higher velocity of gasses leaving furnace to achieve solid separation like using centrifugal action generally have higher pressure drops thus higher auxiliary consumption. Boiler designs with lower velocity of gases have comparatively negligible pressure drop and much lower auxiliary consumption.
Availability and lower maintenance
Maintenance of boiler is directly related to the quantum of refractory the boiler design carries. Boiler design with least level of thick, uncooled refractory and no hot expansion joints, reduces the expenses and the lost time associated with refractory maintenance. If the particle separators and super heater enclosures are constructed entirely of top-supported, gas-tight, all welded membrane tube walls. These systems do not require hot expansion joints, the maintenance over the lifetime of the boiler can be minimised substantially.
Some boiler designs ensure that there is no soot formation and uniform furnace temperature profile is maintained. Erosion is a major cause of maintenance problems in CFBC boilers due to high solid load in the flue gas. The severity of this erosion is exponentially related to the velocity of the flue gas through the system. While some CFBC designs have the particle separator based on an extremely high flue gas velocity. The high velocity provides the energy needed to efficiently disengage the particles from the flue gas. Other designs have particle separator designed to operate efficiently with much lower flue gas velocity (5 to 6 m/s) at full-load operating conditions. By operating at such a low gas velocity, the potential for erosion in these designs is reduced significantly.
Considerations in multi fuel firing
Calorific Value
The lowest calorific value like washery will call for higher amount of fuel feeding into bed. The feeders need to be sized for 1:10 turndown.
Moisture
The furnace cross section is decided by the maximum flue gas volume generated by respective fuel. In case of lignite or biomass with high moisture, low calorific value fuel, the flue gas generated will decide the cross-section dimension of furnace. In addition to this the ESP, ID fans need to be sized for handling higher gas volumes.
Ash
Higher ash content in fuels enhances the heat transfer rate in furnace. To maintain solids mass flux in furnace, the excess solids are taken out of system through bed ash cooler, located beneath the boiler. Hence, for high ash fuels like Indian coal, washery rejects, the number of ash cooler is to be decided based on the high ash fuel. The ESP will see higher dust loading in Indian coal; hence higher collection area will be required comparative to when firing petcoke or imported coal.
Sulfur content
Imported, Indian coal, lignite, petcoke possess sulfur in the order of 0.7, 0.5, 2, 8 per cent in the fuel. In CFB the sulfur capture is done by adding limestone along with fuel. Limestone reacts with sulphate forming sulfur tri oxide that is removed through bed drains.
Hence, high sulfur in petcoke will require higher limestone content and hence the limestone RAVs will be sized to deliver the required quantity. These parameters must be given serious consideration before investing in a specific combustion technology.
Vivek Taneja
Head-Business Development, Thermax, Power Divison.
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Economy & Market
TSR Will Define Which Cement Companies Win India’s Net-Zero Race
Published
2 months agoon
April 27, 2026By
admin
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
Reimagining Logistics: Spatial AI and Digital Twins
Published
3 months agoon
April 13, 2026By
admin
Digital twins and spatial AI are transforming cement logistics by enabling real-time visibility, predictive decision-making, and smarter multi-modal operations across the supply chain. Dijam Panigrahi highlights how immersive AR/VR training is bridging workforce skill gaps, helping companies build faster, more efficient, and future-ready logistics systems.
As India accelerates infrastructure investment under flagship programs such as PM GatiShakti and the National Infrastructure Pipeline, the pressure on cement manufacturers to deliver reliably, efficiently, and cost-effectively has never been greater. Yet for all the modernisation that has taken place on the production side, the end-to-end logistics chain, from clinker dispatch to the last-mile delivery of bagged cement to construction sites, remains a domain riddled with inefficiencies, opacity and manual decision-making.
The good news is that a new generation of spatial computing technologies is now mature enough to transform this reality. Digital twins, spatial artificial intelligence (AI) and immersive augmented and virtual reality (AR/VR) training platforms are converging to offer cement producers something they have long sought: real-time visibility, autonomous decision-making at the operational edge, and a scalable solution to the persistent skills gap that hampers workforce performance.
Advancing logistics with digital twins
The cement supply chain is uniquely complex. A single integrated plant may manage limestone quarrying, kiln operations, grinding, packing and despatch simultaneously, with finished product flowing through rail, road, and waterway networks to reach hundreds of regional depots and distribution points. Coordinating this network using spreadsheets, siloed ERP data, and phone calls is not merely inefficient; it is a structural liability in a competitive market where delivery reliability is a key differentiator.
Digital twin technology offers a way out. A cement logistics digital twin is a continuously updated, three-dimensional virtual replica of the entire supply chain, from the truck loading bays at the plant to the inventory levels at district depots. By ingesting data from IoT sensors on conveyor belts and packing machines, GPS trackers on road and rail fleets, weighbridge records, and weather feeds, the digital twin provides planners with a single, authoritative picture of where every ton of cement is, in real time.
The value, however, goes well beyond visibility. Because the digital twin mirrors the physical system in dynamic detail, it can run scenario simulations before decisions are executed. If a primary rail corridor is disrupted, logistics managers can model alternative routing options, shifting volumes to road or coastal shipping, and assess the cost and time implications within minutes rather than days. If a packing line at the plant is running below capacity, the twin can automatically recalculate dispatch schedules downstream and alert depot managers to adjust receiving resources accordingly.
For cement companies operating multi-plant networks across geographies as varied as Rajasthan and the North-East, this kind of end-to-end situational awareness is transformative. It collapses information latency from hours to seconds, enables proactive rather than reactive logistics management, and creates the data foundation upon which AI-driven decision-making can be built. Companies that have deployed logistics digital twins in comparable heavy-industry contexts have reported reductions in transit time variability of up to 20 per cent and meaningful decreases in demurrage and detention costs, savings that flow directly to the bottom line.
Smart logistics operations
A digital twin is only as powerful as the intelligence layer that sits on top of it. This is where Spatial AI becomes the critical differentiator for cement logistics.
Traditional logistics management systems are reactive. They record what has happened and flag exceptions after the fact. Spatial AI systems, by contrast, are proactive. They continuously analyse the state of the logistics network as represented in the digital twin, identify emerging bottlenecks before they crystallise into delays, and recommend corrective actions.
At the plant gate, AI-powered visual inspection systems using spatial depth-sensing cameras can assess truck conditions, verify load integrity and confirm seal tamper status in seconds, replacing the manual checks that currently slow throughput. At the depot level, Spatial AI can monitor stock drawdown rates in real time, cross-reference them against pending customer orders and inbound shipment ETAs, and automatically trigger replenishment orders when safety thresholds are approached. In transit, AI systems processing GPS and telematics data can detect anomalous vehicle behaviour, including extended stops, route deviations, speed irregularities and alert fleet managers instantly.
Perhaps most significantly for Indian cement logistics, Spatial AI can optimise the complex multi-modal routing decisions that are central to competitive cost management. Given the variability in road quality, seasonal accessibility, rail rake availability, and regional demand patterns across India’s vast geography, the combinatorial complexity of routing optimisation is beyond human planners working with conventional tools. AI systems can process this complexity continuously and adapt routing recommendations as conditions change, reducing empty running, improving vehicle utilisation and cutting fuel costs.
The agentic dimension of modern AI is particularly relevant here. Agentic AI systems do not merely analyse and recommend; they act. In a cement logistics context, this means an AI system that can, within pre-authorised boundaries, directly communicate revised dispatch instructions to plant teams, update booking confirmations with freight forwarders and reallocate available rail rakes across plant locations, all without waiting for a human to process a recommendation and make a call. For logistics executives, this represents a genuine shift from managing a workforce to setting the rules of engagement and reviewing outcomes. The operational tempo achievable with agentic AI simply cannot be matched by human-in-the-loop systems working at the pace of emails and phone calls.
Bridging the skills gap
Technology investments in digital twins and spatial AI will deliver diminishing returns if the human workforce cannot operate effectively within the new systems they create. This is a challenge that India’s cement industry cannot afford to underestimate. The sector relies on a large, geographically dispersed workforce, including truck drivers, depot managers, despatch supervisors, fleet maintenance technicians, many of whom have been trained on paper-based processes and manual workflows. Retraining this workforce for a digitised, AI-augmented environment is a substantial undertaking, and conventional classroom or on-the-job training methods are poorly suited to the scale and pace required.
Immersive AR and VR training platforms offer a fundamentally different approach. By creating photorealistic, interactive simulations of logistics environments, such as a plant dispatch bay, a depot yard, the interior of a cement truck cab, allow workers to practice complex procedures and decision-making scenarios in a safe, consequence-free virtual environment. A depot manager can work through a simulated rail rake delay scenario, making decisions about customer allocation and communication
without the pressure of real orders being affected. A truck driver can practice the correct procedure for securing a load of bagged cement without the risk of a road incident.
The learning science case for immersive training is compelling. Studies consistently show that experiential, simulation-based learning produces faster skill acquisition and higher retention rates than didactic instruction, with some research indicating retention rates three to four times higher for VR-based training compared to classroom methods. For complex operational procedures where muscle memory and situational awareness matter as much as conceptual knowledge, the advantage of immersive simulation is even more pronounced.
Today’s leading cloud-based spatial computing platforms enable high-fidelity AR and VR training experiences to be delivered on standard mobile devices, removing the hardware barrier that has historically made immersive training impractical for large, distributed workforces. This is particularly relevant for cement companies with depots and logistics operations in tier-two and tier-three locations, where access to specialised training hardware cannot be assumed.
The integration of AR into live operations also creates ongoing learning opportunities beyond formal training programs. As an example, maintenance technicians equipped with AR overlays can receive step-by-step guidance for equipment procedures directly in their field of view, reducing error rates and service times for critical plant and fleet assets.
New strategy, new horizons
India’s cement industry is entering a period of intensifying competition, rising logistics costs, and demanding customers with shrinking tolerance for delivery variability. The companies that will lead over the next decade will be those that treat logistics not as a cost centre to be minimised, but as a strategic capability to be built.
Digital twins, spatial AI and immersive AR/VR training are not distant future technologies, they are deployable today on infrastructure that Indian cement companies already operate. The question is not whether to adopt them, but how quickly to do so and where to begin.
About the author:
Dijam Panigrahi is Co-Founder and COO of GridRaster Inc., a provider of cloud-based spatial computing platforms that power high-quality digital twin and immersive AR/VR experiences on mobile devices for enterprises. GridRaster’s technology is deployed across manufacturing, logistics and infrastructure sectors globally.
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