Electric Kilns for Cement/Lime
High Temp Decarbonization:
Calcination: ~900–1,050°C in precalciner, ~1,400–1,500°C in rotary kiln.
Calcination: ~900–1,050°C in precalciner, ~1,400–1,500°C in rotary kiln.
Electrified calcination via electric kilns or using green hydrogen burners offers the potential to deeply decarbonize cement and lime production, eliminating combustion-based CO2 emissions and enabling CO2 capture. These technologies operate at extremely high temperatures (~1,400–1,500 °C) and face technical scaling challenges, but advanced pilots indicate feasibility. Deploying them commercially hinges on access to clean electricity or H2, infrastructure, and integrating CCS to address the chemical CO2 released during calcination.
Cement & lime kilns emit ~0.6–0.9 t CO2/ton cement, with ~60% from calcination (chemical release) and ~40% from fossil-fuel heat. Electrifying kiln heat with electricity or H2 can eliminate fossil-fuel CO2 emissions, and electrified setups can concentrate CO2 for capture.- Electric Rotary Kilns: Pilot projects electrically heat (using resistive, inductive, or plasma) rotary and fluidized-bed kilns for cement and lime, offering full substitution of fossil fuels in the calciner and enabling high-purity CO2 capture.
- Hydrogen-Fuelled Calciners: Projects use 100% H2 use in precalciner stages, showing reduced temperature requirements, lower NO?, but increased hydrogen cost and burner design considerations.
Industrial Impact
- Electric arc melting: Graphite electrodes generate arcs reaching ~1,800 °C to melt steel feedstock.
- Feedstock flexibility: Runs on 100% scrap or hybrid input (scrap + DRI), including green hydrogen-derived DRI.
- Refining stages: Equipped with emission control, alloying, and continuous casting systems for end-product quality.
Emissions & Efficiency Impact
- CO2 Elimination: Replacing fossil heat removes 40% of kiln emissions; green H2 or electricity reduce combustion CO2 entirely. Up to ~0.9 t CO2 avoided per ton cement.
- Pure CO2 Streams: Electrified kilns enable concentrated flue gas, simplifying CCS.
- O2 Partial Pressure: H2 reduces required calcination temp and lowers NO.
Supply Chain & Bottlenecks
- Hydrogen Supply: Requires secure, low-cost green H2 and infrastructure—electricity-based H2 needs renewables, storage, transpor.
- Tech Readiness: Electric kiln pilots exist (VTT), but MW-scale deployment is early.
- Burner & Heat Design: H2 flame characteristics may require hybrid fuels or flame-shaping for effective heating.
- CapEx & Integration: Electric elements, control systems, and CCS units add cost — but fuel savings and emissions reduction may justify investment.
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