Process for product gas circulating calcination of limestone and resource recycling of carbon dioxide

Belonging to the technical field of industrial energy conservation and emission reduction, the invention provides a process for product gas circulating calcination of limestone and resource recyclingof carbon dioxide. The process includes: purifying the CO2 discharged from a lime calcining shaft kiln, then firstly introducing the purified CO2 to a lower cooling section of the shaft kiln, utilizing the waste heat of a high-temperature lime product for preliminary heating, and then performing heating by a regenerative heating furnace to 1200DEG C; introducing the heated high-temperature CO2 asa heat carrier into a middle calcination section of the shaft kiln to supply heat to the limestone calcining process; at the end of calcination, letting the CO2 serving as the heat carrier and the newly produced CO2 enter an upper preheating section of the shaft kiln together to preheat the unreacted limestone; and then discharging the CO2 from a side face of the top part of the preheating sectionfor next circulation. The