Abstract: Methods and systems for removing impurities (e.g. volatile organic compounds, water) from process gas streams, including condensing and freezing of the process gas stream, are provided herein.

Abstract: Methods and systems for recovering alkene (e.g., C2-C4 alkene) gas as well as producing pressurized alkene (e.g., C2-C4 alkene) gas from process gas streams including lower concentrations of alkenes are provided herein.

Abstract: Methods and systems for recovering alkenes (e.g. ethylene, propylene) from process gas streams, including multi-step condensing of the process gas stream, are provided herein.

Abstract: Methods and systems for recovering alkenes (e.g. ethylene, propylene) and nitrogen from process gas streams, including multi-step condensing of the process gas stream, are provided herein.

Abstract: Methods and systems for recovering alkene (e.g., C2-C4 alkene) gas as well as producing pressurized alkene (e.g., C2-C4 alkene) gas from process gas streams including higher concentrations of alkenes are provided herein.

Abstract: Methods and systems for recovering nitrogen and alkenes (e.g. ethylene, propylene) from process gas streams, including multi-step condensing of the process gas stream, are provided herein.

Abstract: A method for treating pulp through oxygen delignification and ozone bleaching is disclosed. The method uses a modified oxygen recovery unit which separates a mixture of oxygen and ozone thereby generating a stream of ozone and a stream of oxygen; feeding the stream of oxygen to an oxygen delignification unit; feeding a pulp to the oxygen delignification unit; feeding the stream of ozone to an ozone bleaching unit; feeding the delignified pulp to the ozone bleaching unit; and recovering the delignified and bleached pulp.