EXHAUST HEAT RECOVERY STEAM BOILER USING THE TWO BOILERS

摘要

The present invention relates to a waste heat recovery steam boiler using two boilers. The waste heat recovery steam boiler of the present invention comprises: a water storage tank (10); a first boiler and a second boiler (20, 30) respectively with a first water supply pipe and a second water supply pipe (21, 31) to supply water stored in the water storage tank (10); a first exhaust pipe and a second exhaust pipe (22, 32) connected for a combustion gas inside to be discharged to the outside; and a first steam supply line and a second steam supply line (23, 33) connected for the internal steam to be supplied into a flow path; a first waste heat recovery unit and a second waste heat recovery unit (40, 50) installed in an outer circumferential surface of each of the first exhaust pipe and the second exhaust pipe (22, 32) to be positioned at a certain interval; a raw water line (60) to supply water outside the flow path into the first waste heat recovery unit (40); a circulating line (70) to supply the water stored in the water storage tank (10) into the second waste heat recovery unit (50); a recovery line (80) to recover the water on which heat exchange is conducted in the second waste heat recovery unit (50) to the water storage tank (10); a circulating pump (90) placed in the circulating line (70) to selectively supply the water in the water storage tank (10) to the second waste heat recovery unit (50); and a return line (RW). The waste heat recovery steam boiler of the present invention recovers heat of the combustion gas using two boilers, supplies the preheated water to the boiler, and heats the water. Therefore, when the waste heat recovery steam boiler of the present invention is continuously operated, the temperature of the preheated water gradually increases, and the heat required to make water into steam is reduced. As a result, the thermal energy consumed to operate a boiler is reduced.