Ashok Dembla, President and Managing Director, KhD Humboldt, in conversation with Kanika Mathur about the use of technology in the grinding process.

The cement industry, responsible for nearly seven per cent of global CO2 emissions, faces a pressing challenge: balancing growth with sustainability. As companies strive for net-zero emissions, innovations in alternative fuels, carbon capture, and energy efficiency are reshaping the sector. From blended cement to cutting-edge kiln electrification, the industry is moving toward a future beyond carbon. In this interview, ICR explores the evolving technologies and strategies driving cement’s decarbonisation journey.

Tell us about cement beyond carbon.
The cement industry contributes approximately 7 per cent of global carbon dioxide emissions, making it one of the largest industrial contributors to climate change. This places a great responsibility on the industry to reduce emissions and promote sustainability. It becomes a moral obligation for us to work toward carbon neutrality or even carbon negativity to protect the environment and ensure a sustainable future for humanity.
Many companies in the cement industry have already pledged to achieve net-zero emissions by 2050 or beyond. At KHD, our focus is on technological innovation to achieve the vision of cement beyond carbon. Cement remains an essential material for infrastructure development and economic growth, and the challenge is to meet this demand while minimising its carbon footprint.
Currently, conventional methods like producing blended cement, which uses less clinker and more fly ash or slag, have been instrumental in reducing emissions. Additionally, technologies like Waste Heat Recovery (WHR) systems have seen significant adoption in India. WHR systems allow plants to recover and reuse heat, improving efficiency. Another method is the use of Alternative Fuels and Raw materials (AFR). While the industry was at just 4 per cent usage of AFR previously, we have now reached around 7 per cent, with an ultimate goal of surpassing 35 per cent, which is the global benchmark.
However, these conventional methods alone will not suffice to achieve complete decarbonisation. Advanced technologies are being explored, such as capturing carbon dioxide from exhaust gases, improving system efficiencies, and implementing oxy-fuel combustion or electrification of kilns. While these technologies are still in various stages of development, I believe they will become economically viable after 2030. The industry’s focus is on continuous research and development to integrate these technologies into our processes effectively.

How is your technology adapting to changing fuels and raw materials?
The use of alternative fuels and raw materials (AFR) is continuously evolving within the cement industry. As a machinery supplier, we are adapting to these changes by providing advanced solutions for handling and processing AFR. One of our most significant innovations is the PyroRotor, an equipment designed specifically for feeding up to 85 per cent of alternative fuels into the pyroclone, which is far beyond what conventional methods can achieve. This has greatly enhanced our ability to replace traditional fuels with more sustainable alternatives.
In addition, we have developed solutions to address nitrogen oxide (NOx) emissions, a critical environmental concern. Our NOx reduction equipment significantly minimises NOx generation during the production process, helping plants meet stringent regulatory requirements.
Optimisation is another critical focus area. Through digitisation and advanced process control systems like PRO-MAX, we are able to optimise the entire cement production process. This system includes kiln and mill control modules, allowing plants to operate more efficiently and reduce both thermal and electrical energy consumption.
Globally, the industry is also moving toward more advanced technologies, such as increasing oxygen content in fuel firing and capturing carbon dioxide directly from flue gases. While these technologies are already being implemented in some European plants, they require significant capital investment and governmental support. India is also taking steps in this direction, with plans for model plants to showcase the viability of these advanced solutions.

Do any of your solutions have an impact on energy utilisation in cement plants?
Energy utilisation in cement plants involves two main types: thermal energy and electrical energy. On the thermal energy front, significant progress has been made over the past decade. Previously, plants required around 750 kilocalories per kilogram of clinker. Today, this has been reduced to 685 kilocalories or even lower, thanks to continuous improvements in process efficiency.
For electrical energy, we have optimised systems like the roller press, which enhances the efficiency of raw material grinding and cement grinding. These advancements have significantly reduced energy consumption per ton of clinker produced.
Energy optimisation is an ongoing process. By integrating advanced technologies and optimising plant operations, we aim to achieve even greater reductions in energy consumption, contributing to both cost savings and environmental sustainability.

How do you see the journey toward net zero unfolding, and what is your perspective on this?
The journey toward net zero is both challenging and rewarding. One of the critical areas we have focused on is the increased use of alternative fuels and raw materials (AFR). The technology to utilise AFR is available, but its successful implementation depends on a well-organised system for waste collection and processing.
In India, progress has been made in cities like Indore and Bengaluru, where systems for waste segregation and preparation are more developed. However, there is still a long way to go to make this a common practice across the country. Government support is crucial in this regard, especially in establishing efficient logistics systems to transport waste from its generation point to cement plants for use as fuel.
Collaboration between industries, government bodies, and city administrations is essential to achieve the full potential of AFR utilisation. The ultimate goal is to make the use of AFR economically viable while ensuring that the logistics and supply chain challenges are effectively addressed.
Net zero is not just a technological goal; it is a systemic change that requires the entire ecosystem to work together. While the industry has made significant strides, much work remains to be done to make net zero a reality.