Longitudinal finned tube flue gas heat exchanger rig

The utility model relates to a longitudinal finned tube flue gas heat exchanger rig for cooling or heating the flue gas in the desulfuration engineering of boiler tail gas. The utility model comprises a heat exchanging tube, a small header, a big header and an outer shell. The heat exchanging tube comprises an inner tube and fins. The outer surface of the inner tube presents a radial shape along the radial direction and is uniformly distributed with multiple fins. Each fin linearly extends along the longitudinal direction of the inner tube. Multiple longitudinal finned heat exchanging tubes comprise a group with the small header. And multiple longitudinal finned heat exchanging tubes comprise one entirety with the big header. The cooled or heated fume longitudinally flows along the longitudinal fin tube. The fume flow passage is of a longitudinal straight-way type, and is parallel to the flowing path of the heat exchanging media water.