The invention discloses a straight 
pipe header coil 
pipe type reactor for waterway natural circulation. The heat exchange 
pipe bundles comprise a water outlet pipe, an upper straight pipe header, coil pipes, a lower straight pipe header, 
branch pipes, annular pipes and a water inlet pipe, the 
water discharge pipe is connected to the top of a pressure-loaded housing, the upper straight pipe header is connected to an inlet of the 
water discharge pipe and outlets of the coil pipes respectively, the coil pipes are distributed in the axial direction of the pressure-loaded housing, the lower straight pipe header is connected to inlets of the coil pipes and outlets of the 
branch pipes respectively, the water inlet pipe is connected to the bottom of the pressure-loaded housing, and the annular pipes are connected to a water inlet pipe and the 
branch pipes respectively. According to the straight pipe header coil pipe type reactor for the waterway natural circulation, the coil pipes are adopted as a main heat exchange pipe bundle, the coil pipe bundle thoroughly removes thermal stress in the axial direction and the radial direction; an outer air cylinder and inner air cylinder technology are adopted to ensure air radically flow through a catalyst 
bed layer, and the flow directions of the air and water are in a perpendicular state; waterway circulation between the vapor bag and the coil pipe bundle is adopted as natural circulation, and the waterway circulation percentage is high; the catalyst is high in filling amount, strong in heat motion ability and easy for upsizing.