IDTechEx Explores Innovation in Carbon Capture Technology - Seite 2

Research is focusing on overcoming these issues, with companies developing proprietary amine-based solvents for next-generation carbon capture projects, such as the KS-1 Solvent developed by Mitsubishi, used in the Petra Nova facility in Texas, and Shell Global's CanSolv Solvent, which is used in the Boundary Dam CCS project in Canada. Options include sterically-hindered amines that form weaker bonds with CO₂ during the reaction, facilitating solvent regeneration, non-amine solvents that can offer novel chemical trapping mechanisms, and blends of amines and/or non-amines that can optimize CO₂ capture for a given situation.

Physical absorption solvents selectively capture CO₂ when in contact with a gas stream without a chemical reaction occurring. Compared with chemical absorption, physical absorption solvent regeneration is relatively easy and doesn't require elevated temperatures, although physical absorption solvents are often less selective than chemical absorption solvents and can be ineffective at low CO₂ partial pressures.

Unlike chemical absorption solvents, physical absorption solvents utilize a range of different compounds, with each solvent being suited to a specific use case. For example, the Rectisol process, licensed by Lurgi AG, an affiliated company of Air Liquide, uses chilled methanol as a solvent and can be applied for low and moderate CO₂ concentrated gas streams. Due to the high vapor pressure of the solvent, the absorption stage must be carried out at very low temperatures to reduce solvent losses.

Research is now focusing on developing physical solvents with high thermal stability, improved selectivity, low vapor pressures, and low flammability and toxicity. Promising avenues include fluorinated solvents and ionic liquids, however, both face challenges with high viscosities and production costs.

Although liquid amine scrubbing technology (i.e., chemical solvent-based capture) will likely dominate carbon capture for the next few years, there is much interest in alternative methods for CO₂ capture, although it remains predominantly at the academic research level. Promising options include solid sorbent-based CO₂ capture and membrane-based CO₂ separation, although there is a range of other emerging techniques, such as cryogenic separation, electrochemical membranes, and additive manufacturing of novel system components and materials.