Reengineering of the carbon-to-acetylene process featuring negative carbon emission

Abstract

Various sources of carbon can be converted into acetylene (C₂H₂) by using the key intermediate calcium carbide (CaC₂). However, the production of CaC₂ is a typical energy-intensive process, accompanied by considerable carbon dioxide (CO₂) emissions and a large amount of industrial solid waste. In this study, a sustainable methodology for carbon-to-acetylene and carbon monoxide (CO) co-production as well as CO₂ capture based on BaCO₃−BaC₂−Ba(OH)₂−BaCO₃ looping was first established, in which BaC₂ replaced CaC₂ as the key intermediate of the carbon-to-acetylene process to generate C₂H₂. The kinetic behavior investigation of the BaC₂ formation indicated that the solid-phase synthesized BaC₂ is a promising intermediate for the carbon-to-acetylene conversion owing to its faster kinetics, lower formation temperature, and no carbon dioxide release compared with those observed for the CaC₂ production. Moreover, the lab-scale recovery of barium to carbide formation was conducted as the proof-of-concept to validate the coupling process of carbon-to-acetylene with CO₂ capture based on Ba looping, resulting in less carbide slag waste and negative carbon emission. The facile co-production of carbon monoxide, environmentally friendly process, and convenience of large-scale production, as well as possible independent manufacturing of fossil resources, make barium carbide-based carbon-to-C₂H₂ -CO a promising key chemical platform for sustainable development. The proposed technology would provide new insights into the reengineering process of carbon to chemicals.