A system to calcine crushed carbonate, discharge alkaline oxide, and deliver an enhancing fluid having CO2, comprising: a pressurized insulated calciner having descendingly, a crushed alkaline carbonate feeder, a calciner fluid outlet manifold, a heated sideflow calciner fluid intake manifold, a preheated sideflow calciner fluid outtake manifold, a fluid inlet manifold to recirculate calciner fluid from the outlet manifold, and an alkaline oxide discharger; a pressurizer to repressurize sideflow calciner fluid, connected to intake and outtake manifolds; pressurizers to recirculate calciner outlet fluid to the inlet manifold, pressurize the calciner and deliver enhancing fluid comprising CO2; delivery and combustion systems to form a combustion fluid; a recuperating or regenerating refractory heat exchanger to heat sideflow calciner fluid with combustion fluid connected to the sideflow pressurizer, and fluid outtake and intake manifolds; and a controller operable to control combustion, heat exchange, calciner fluid formation and delivery, carbonate feed and oxide discharge.