EXHAUST GAS RECIRCULATION SYSTEM, SHIP BOILER EQUIPPED WITH THE SAME, AND EXHAUST GAS RECIRCULATION METHOD

摘要

PROBLEM TO BE SOLVED: To keep down an exhaust gas recirculation system to be added to a minimum and to reduce NOx discharged from a ship boiler.SOLUTION: An exhaust gas recirculation system comprises: a boiler 1; a first inert gas line 33 branched off from a passage discharging boiler exhaust gas produced by combustion in the boiler 1 and circulating inert gas into a crude oil tank 22 via a scrubber 25; a VOC gas line 34 circulating VOC gas into a fire furnace of the boiler 1 or a burner 3 from the crude oil tank 22 via a VOC gas filter 27; an inert gas bypass line 21 connecting a side downstream of the scrubber 25 on the first inert gas line 33 to a side upstream of the VOC gas filter 27 on the VOC gas line 34; and a controller 50 controlling the inert gas to be circulated into the inert gas bypass line 21 to supply the inert gas to either the boiler 1 or the burner 3 if the VOC gas generated from the crude oil tank 22 is equal to or lower than a predetermined value.