Condensation energy-saving low-nitrogen-emission gas normal-pressure heating boiler

The utility model belongs to the technical field of normal-pressure gas-fired boilers, and relates to a condensation energy-saving low-nitrogen emission gas-fired normal-pressure heating boiler whichcomprises a boiler body and a boiler chimney, and a smoke condensation device is arranged between a rear tube plate of the boiler body and the boiler chimney. The flue gas condensing device comprisesa shell, a shell sealing plate, a flue gas flow guide heat exchange water jacket, a coiled pipe group, a water distribution pipe and a flue gas outlet; the flue gas flow guide heat exchange water jacket and the coiled pipe group are arranged in the space in the shell; a water inlet is formed in the lower end of the boiler body; the water inlet is communicated with the lower end of the smoke guideheat exchange water jacket; the upper end of the smoke guide heat exchange water jacket is communicated with the upper end of the coiled pipe group, the lower end of the coiled pipe group is connectedwith one end of the water d