GAS BURNER

Gas (1) in many industrial furnaces because of its cleanliness, ease of control of furnace atmosphere, ability to produce a long slow burning flame with uniform and gradual energy liberation, and ease of temperature regulation. Natural gas is used for steam generation in gas-producing areas and in areas served by natural-gas transmission lines[7] where coal is not available at a competitive price. It is also burned (2) in coal-or oil-fired units[8] during the summer months in districts served by natural-gas pipe lines, at which time the absence of the domestic heating load creates a temporary surplus of natural gas. By-product gas such as blast-furnace gas may be available at the steel mills for steam generation. Because of the variable or seasonal supply of (3), combination burners have been developed to permit the simultaneous burning of the available gas together with pulverized coal or oil in an amount sufficient to produce the required steam.

When a molecule of combustible gas is mixed with the oxygen necessary for its combustion at a temperature above the (4), combustion is practically instantaneous. For (5), where a short flame is desired in order (6) the required furnace volume, the burner should provide for rapid and thorough mixing of the fuel and air in the (7) for good combustion. For such applications, a good burner is primarily a proportioner and mixing device. In (8) where long "lazy" flames are desired, slow and gradual mixing of the air and fuel in the furnace is necessary.

In the burner the gas, under pressure in the supply line, (9) the furnace through a burner port and induces a, flow of air through the port. Mixing is poor, and a fairly long flame results. The flame (10) by use of the ring burner, in which the gas flows through an annular ring and induces air flow both around and within the annulus of gas.