Tubular fixed bed reactor

The utility model aims to provide a tubular fixed bed reactor capable of avoiding the situation that the heat exchange effect becomes poor due to heat accumulation at local positions in the reactor, the reactor comprises a main body piece, and an upper tube plate and a lower tube plate which are arranged at the upper end and the lower end of the main body piece, a hollow heat exchange cavity for storing a heat exchange medium in the reactor is defined by the components; a heat exchange tube nest is fixedly arranged in the heat exchange cavity, and the two ends of the heat exchange tube nest penetrate through the upper tube plate and the lower tube plate correspondingly to form a feeding port and a discharging port; a medium inlet allowing a heat exchange medium to enter the heat exchange cavity and a medium outlet allowing the heat exchange medium to leave the heat exchange cavity are further formed in the main body piece, and a flow guide structure capable of promoting and guiding the heat exchange medium in