Integration of Direct Air Capture with the Chlor–Alkali Process for CO2 Mineralization: Techno-Economic and Life Cycle Assessment

[Geoengineering News]

https://www.sciencedirect.com/science/article/abs/pii/S0360544226014520

Authors: Minseok Im, Konan Alain Cedric Nzisso, Inhye Kim, Cheol Hun Park, Sunghyun Cho

15 May 2026

https://doi.org/10.1016/j.energy.2026.141346

Highlights

•Proposed CADAC combines DAC with chlor-alkali process for synergistic benefits.

•HEN integration achieved 93.4% heat recovery, reducing utility demand up to 65.5%.

•LCOD range: from −2181 to +276 USD tonne−1 CO2; 13.6 times higher sensitivity to electricity than carbon credits.

•Nuclear, hydro, wind, and CSP scenarios achieved carbon-negative operations.

•Parametric analysis identified 44% renewable electricity threshold for net-zero emissions.

Abstract

Although direct air capture (DAC) is a promising negative-emission technology, its widespread deployment remains hindered by high energy requirements and unfavorable economics. This paper presents a novel configuration integrating DAC with a chlor–alkali (CA) process referred to as the CADAC system. Key innovation involves directly supplying Ca(OH)2 from the CA process to the DAC unit, eliminating the energy-intensive calciner–slaker loop required in conventional DAC configurations. Comprehensive technoeconomic and life cycle assessment are conducted to evaluate system performance. Economic analysis results confirm that the CADAC system achieves net profit margins of 18.0–35.1 M USD yr−1, a 62–216% improvement over the standalone CA process with heat exchanger network integration. The levelized cost of DAC (LCOD) remains negative across most evaluated scenarios, indicating net revenue generation during CO2 capture. Environmental assessment reveals a 72.7% reduction in global warming potential (GWP) compared to that of the standalone CA process based on brine treatment. Integrating renewable electricity enables carbon-negative operation with GWP values ranging from −3.15 to −3.68 kg CO2-eq kg−1 CO2 captured. Integrating renewable electricity enables carbon-negative operation when the renewable fraction exceeds 44.3% of the total supply, with GWP values ranging from −3.15 to −3.68 kg CO2-eq kg-1 CO2 captured. The sensitivity analysis confirms electricity price as a dominant factor governing system performance, with LCOD being ∼13.6 times more sensitive to electricity prices than that to carbon credit prices. The CADAC system demonstrates sufficient economic and environmental performances for near-term industrial-scale negative-emission deployment in regions with partially decarbonized grids.

Source: ScienceDirect