Energy Consumption and Emissions in Lime Kilns

Quicklime production necessitates high-temperature kilns to perform the calcination reaction, converting limestone into quicklime and CO₂. This analysis compares eight kiln configurations based on energy demand and CO₂ emissions:

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• NG – Conventional natural gas air-fired kiln

• NGOxy – Natural gas oxy-fired kiln for concentrated flue gases

• Plasma – Plasma-based electrified kiln

• BioCH4 – Uses biomethane as a clean fuel

• BioCH4Oxy – Biomethane oxy-fired kiln for concentrated flue gases

• H2Oxy – Hydrogen oxy-fired kiln for concentrated flue gases

• Biomass – Uses solid biomass (wood) as a clean fuel

• BiomassOxy – Biomass oxy-fired kiln for concentrated flue gases

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Energy Demand Components (GJ/t)​

• Q-Process – Thermal energy for limestone calcination

• EL-Process – Electrical demand for kiln operations

• EL-ASU – Electricity for oxygen production in oxy-fuel systems​

• Q-CCS – Heat required by chemical absorption-based CO₂ capture

• EL-CCS – Power required by absorption-based CO₂ capture (Ch.Abs.) or cryogenic CO₂ capture (CO2CPU)

• EL-Electrolyzer – Electricity for green hydrogen production

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Carbon Capture (CCUS) Impact

CCS increases energy demand due to CO₂ separation and compression but reduces overall direct and indirect emissions per ton of lime. This analysis highlights key decarbonization strategies in industrial lime manufacturing.

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