Gas treating solutions containing imidazole-amine compounds and methods of making the same

Inventors

Bara, Jason E. • O'Harra, Kathryn E.

Assignees

University of Alabama at Birmingham UAB

Abstract

Systems comprising a composition where an imidazole is tethered to an amine and a solvent are described herein. Methods of their preparation and use are also described herein. The methods of using the systems include the reduction of volatile compounds from gas streams and a liquid stream.

Core Innovation

The invention is directed to gas-treating solutions and methods based on imidazole-amine compounds, where an imidazole core of formula (I) is tethered to an amine and is provided as an imidazole having formula (I) or a salt thereof in a solvent, including water. The imidazole compounds absorb volatile compounds by forming complexes, and the volatile-compound absorption occurs during contacting a stream with a solution consisting of an imidazole of formula (I) or a salt and a solvent.

The methods reduce or absorb one or more volatile compounds from a gas or liquid stream by contacting the stream with the imidazole-amine compound in the solvent, optionally followed by removal of complexes from the stream. Exemplary stream contexts include flue gas, and the volatile compounds explicitly include carbon dioxide, hydrogen sulfide, sulfur dioxide, nitrogen oxide, nitrogen dioxide, carbonyl sulfide, and carbon disulfide.

A further disclosed use case is sweetening a natural gas feed stream by contacting the natural gas feed stream with an aqueous solution of an imidazole of formula (I) or a salt thereof, forming a purified gas feed stream and a gas-rich solution, and separating the purified gas feed stream from the gas-rich solution. Regeneration is described by heating or pressurizing the gas-rich solution, and solvent constraints include solvent consisting essentially of water.

Claims Coverage

The independent claims include two inventive method categories: reducing volatile compounds from a stream using an imidazole of formula (I) in a solvent and sweetening a natural gas feed stream using the same imidazole solution approach followed by separating purified gas and a gas-rich solution. Across these independent claims, the main inventive features are imidazole-of-formula (I) contacting and complexation for volatile-compound removal and aqueous contacting and phase-separation for natural-gas sweetening.

The independent claims center on contacting a relevant gas stream with a solvent solution containing an imidazole of formula (I) or a salt to capture volatile compounds via complex formation and, for natural gas, separating a purified gas feed stream from a gas-rich solution.

Stated Advantages

Documented Applications