Systems and techniques for the reclamation of carbon dioxide from boiler flue gas as well as for the liquefaction of the reclaimed carbon dioxide for well injection oil recovery are provided. A system can include a boiler, tower scrubber, carbon dioxide absorber, regenerator, reboiler, rectifying tower, condenser and mixing tank. Mixed gases of carbon dioxide and nitrogen for well injection may be reclaimed from boiler flue gas when steam is produced resulting in an increase of crude oil output increase while lessening environmental impact. Related systems, apparatus, methods, and articles are also described.