Oxyfuel Boiler System and Method of Retrofit of Air Fired Boiler to Oxyfuel Boiler

摘要

An oxyfuel boiler system, comprising: an oxygen generator to separate oxygen from air; a coal supply unit to dry and pulverize coal; a burner having a fuel feed path for feeding pulverized coal supplied from the coal supply unit and an oxidizer feed path for feeding oxidizer; a boiler provided with the burner; an exhaust gas discharge line to discharge exhaust gas generated in the boiler into environment; an exhaust gas treatment apparatus provided in the exhaust gas discharge line, a CO₂ separator provided downstream of the exhaust gas treatment apparatus in the exhaust gas discharge line to separate CO₂ from the exhaust gas; an exhaust gas recirculation line including an exhaust gas tapping port provided in the exhaust gas discharge line to extract a part of the exhaust gas; and;an oxygen supply line to supply the oxygen generated at the oxygen generator to the exhaust gas flowing through the exhaust gas recirculation line,;wherein the exhaust gas treatment apparatus is provided with at least an SO₃ removing unit and a moisture removing unit; and the exhaust gas tapping port of the exhaust gas recirculation line is disposed downstream of the exhaust gas treatment apparatus and upstream of the CO₂ separator for recirculating a part of the gas extracted from the port to the coal supply unit and/or the boiler.