Guilherme Mendonca, Head Energy Business, Siemens, elaborates about co-creating innovative technology solutions for the cement industry.

What are the key features of your Waste Heat Recovery System that make it an eco-friendly solution for cement manufacturing?
Steam turbines are the heart of every power plant. In waste heat recovery (WHR), steam turbines act as an essential piece of the whole system. Our modular design concept ensures high flexibility, availability, and efficiency, playing a significant role in many industrial plants for waste heat recovery and cogeneration application. In India different technologies exist to convert thermal heat into power like Steam Rankine Cycle (SRC), Organic Rankine Cycle (ORC) and Supercritical Carbon Dioxide Cycle (sCO2). However, only SRC and ORC are fully commercialised with SRC being a more popular technology with decades of proven results. Through efficient use of our steam turbines our customers can extract high power output with the available waste heat, enabling them to reduce their carbon footprint. Siemens Energy WHR solutions are capable of meeting all these requirements which are specific to the Indian
cement industry.

How does your system help reduce carbon emissions during the cement production process?
Waste Heat Recovery System (WHRS) is a key area for cement producers to improve plant efficiency and reduce their carbon footprint by utilising the waste heat from the cement manufacturing process. Siemens Energy’ waste heat recovery system is highly efficient with Heat ReCycle Power Plants offsetting the emissions when compared to other technology that is typically used to generate equivalent power, like diesel generators and reciprocating engines or small coal fired power plants. This results in overall reduced emissions and reduction in dependability on fossil fuels.

What are the estimated energy savings that can be achieved by installing your system in a cement plant?
These plants are highly customised solutions and savings can vary depending upon various factors such as source of upstream power generation, plant configuration and degree of waste heat available. Given ideal conditions, waste heat recovery power plants can offset approximately 30 per cent of total electricity requirement of a typical cement plant in India. In 2012, the Rohrdorf cement works in Germany commissioned the first waste heat and gas power plant in Europe. The plant produced over 30 per cent of the site’s power while saving 12,000 tpa of fossil fuels and reducing CO2 emissions by 30,000tpa. We have come a long way since then in terms of technology adoption and benefits. In practical applications, plants that have implemented waste heat recovery systems have been proven to reduce carbon intensity by as much as 25kg/t of clinker produced.

How long does it take for the system to pay for itself through energy savings?
The pay-off is faster than conventional grid-connected power plants by up to 40 per cent in an ideal situation. This return-on-investment calculation considers 30 per cent electricity offset and variations in energy prices as well as carbon credits and cost of decarbonisation.

What is the expected lifespan of the system, and what maintenance is required to keep it functioning optimally?
Generally, the operating lifespan of steam-based WHRS is 20 years. Typically, it works for 8,000 operating hours per year. The availability and adoption of digital solutions such as remote diagnostic services that allow proactive, predictive maintenance and minimises forced outages.

Can your system be customised to meet the specific needs of different cement plants?
Yes. This is a fully customised solution taking into account all the cement plant constraints and available waste heat sources and quality of waste heat.

What are the major challenges of a WHRS when installed in a cement plant?
Some key challenges of installing WHRS are design limitations due to available technologies and constraints such as source of heat, space available and integration. With these being mostly brownfield projects, the integration with minimum downtime and minimum process disruption also add to the challenges. However, this can be planned and mitigated with efficient project management from Siemens Energy.

How do you envision your collaboration with the cement industry in the decade to come?
We envision a strong collaboration with the cement industry in the decade to come, which is primarily driven by a shared commitment to sustainability and reducing carbon emissions with WHRS at the centre. We see WHRS as a key technology that can help cement manufacturers achieve their sustainability goals while also providing energy savings and cost reductions. Looking to the future, our collaboration with the cement industry will continue to be focused on co-creating innovative technology solutions that are tailored to the specific needs of individual cement plants in India.

–Kanika Mathur