Leilac’s purpose is to future-proof cement and lime – empowering producers to meet the needs of society, the economy and the environment. Our technology’s hybrid-fuelled design has the potential to not only produce lower cost and lower emissions cement and lime, but it is also designed to provide a valuable balancing service to help create more resilient energy grids.
Over the last six years, Leilac and its parent company, Calix, has expanded the design of its core technology so that the system can operate on a broad range of fuel sources. Several pilot plants have demonstrated operation with either conventional combustible fuels or grid sourced electricity. The success of these campaigns has progressed the technology towards an important goal, hybridisation – where industrial heat can be provided by both electricity and fuel combustion, simultaneously.
Hybrid technologies offer a number of benefits over their traditional, single-fuelled counterparts: they enable cost-efficiency, versatility, redundancy and a marked reduction in overall carbon emissions. The case for hybrid-fuelled heating in cement can be described on three fronts.
1. Cement plants could minimise production costs by dynamically switching to the lowest cost of energy at a given moment
The calcination step is a major, energy-intensive process within cement manufacturing; energy costs for this step are considerable. By replacing this process with a hybrid-fuelled system, a cement plant may reduce energy costs by switching to electricity during periods of low or negatively priced electricity hours. When electricity is more expensive, the same system could be switched back towards conventional or low-cost alternative fuels
2. Cement plants could access new revenue streams from energy balancing activities
By electrifying and integrating a hybrid-fuelled cement plant into the grid, the cement plant has the potential to act as a versatile load-balancing unit, able to flexibly increase or decrease its electricity use on demand. Critically, the second energy input is designed to respond and operate in synchrony with the change in electricity use, enabling flexible demand response services for the grid, without interrupting cement production.
3. Regional power grids could benefit from a new and versatile source of demand-side flexibility
The need for flexibility in our energy grids is increasing. Transmission system operators are increasingly reliant on load balancing services to keep our energy systems secure and reliable. A hybrid-fuelled indirect heating system would introduce a considerable source of flexible load, that could be called on during periods of grid instability.
What is hybridisation?
To envisage hybridisation for cement, consider other hybrid-fuelled heating and combustion technologies. An example would be the operation of a hybrid vehicle; an electric motor regulates between a petrol engine and a battery system to deliver power. The engine and the battery system can operate together or independently to deliver seamless, fuel-efficient driving. Another example would be hybrid fuelled domestic heating systems. These systems regulate between an electric heat-pump and a gas furnace to provide continuous and efficient heating, throughout the year. These systems can respond to changes in domestic gas and electricity prices, and they are well suited to fluctuating seasonal demands.
To hybridise a technology is to re-engineer it with this dual-fuel capability. A hybridised heating system for cement and lime would be able to shift between fuel and electricity use, on demand, without interrupting the core manufacturing process. Once integrated to the grid, the same system would be able to adjust its energy consumption, so that it can provide grid load-balancing services.
How does the Leilac technology enable hybridisation?
In traditional cement production, the hot meal is heated via direct gas exchange. A singular, continuous-duty fuel source drives the preheating and calcination step. If the gas stops for any reason, then the process shuts down. As of yet, there is little scope for electrifying this technology.
By contrast, the Leilac technology uses indirect heating; externally heated tubes deliver radiative heat to calcine the raw meal. Given that the heat source is isolated from the tube’s contents, the core reaction process is kept at one remove from its source of energy.
Most importantly, this configuration creates space for two energy inputs to deliver heat within the Leilac technology (figure 1). Firstly, the tube can be externally heated by fuel burners, which combust fuel within the furnace cavity. Secondly, a powerful current can be applied to the inner tube, converting the tube into a resistive heating element. Both sources of heat can drive the calcination reaction within the inner tube, either independently (single-fuel operation) or simultaneously (dual-fuel operation). The source of the combustion fuel is also flexible, and could include Natural Gas, Alternative Fuel, biomass or hydrogen.
Unlocking hybridisation for cement and lime: The next steps
Leilac has embarked on an ongoing development campaign to transform our core technology into a hybridised, multi-fuel system. In 2019, The Leilac-1 pilot plant used natural gas as a fuel source to successfully demonstrate indirect heating for cement. The Leilac-2 project, which is expected to be commissioned in 2026, will utilise alternative fuels to power a scaled-up demonstration plant. In 2020, Calix’s pilot-scale BatMn reactor proved that this technology can be powered through electrification. In 2023, Calix’s pilot-scale project, Thor’s Hammer, successfully re-engineered the core technology to demonstrate direct ‘calciner-tube’ heating, a new approach to electric heating that does not require external electric heating elements.
The deep decarbonisation of the global cement and lime industries will a require a versatile, multi-pronged approach. Leilac’s hybrid-fuelled technology is the embodiment of this approach, providing multiple benefits to both cement manufacturers and their regional electricity grids.
Through hybridisation, manufacturers will be able to prioritize the lowest cost of energy for the lowest cost of production. The same manufacturer will be able to engage in energy balancing activities, gaining new revenue streams for their plant and enhancing the economics of decarbonisation, whilst providing much needed source of flexibility for regional power grids.
The benefits of hybrid heating can be stacked with other benefits of the Leilac technology, such as process CO2 emission capture, that can be added either immediately or when market conditions allow.
To learn more about Leilac’s hybrid-fuelled approach, or any of the other benefits our technology offers, please email us at contact@leilac.com.
