This invention discloses a gas waste heat boiler under the normal air pressure. And it is a tube-like unit which connects with the powered coal gasification stove outlet and the whirl separator, the character of which is that the inner side of the tube-like unit is the water room 6 with two layer metal wall, wherein the heat insulation layer 9 is between the water room 6 and the tube-like case, the down and up end of the water room are the down annular container 4 and the up annular container 5 respectively, and the two annular containers connect with the water circuit and the carbonated drink circuit respectively; a group of the tubes 7 are arranged parallely on the gas channel among the annual wall of the water room and connect with the water room 6, and the outer end of the up and down annual container all have the up interface 2 and the down interface 3 with insulation layers. And the frame 8 of the fixed boiler is welded at the case; the pipes 7 are used by the deep wall alloy steel pipe, the pipes are arranged aslant, and the anterior pipes have the wear preventive cover. |