SU872918A1 - Low-oxidation heating gas furnace - Google Patents

Description

(54) GAS OVEN OF LOW-OXIDATIVE HEATING

I

The invention relates to furnaces for heating a metal before pressure treatment and can be used in the metallurgical, engineering and other industries.

A furnace of low-oxidative heating of a metal with aerodynamic separation of the oxidation and reduction zones is known, containing () a working chamber, under the burner and nozzle of the secondary air 1.

However, it is difficult to provide low oxidation heating of the billets in the furnace and to achieve high technical and economic indicators due to the fact that in the furnace there is mixing of the products of complete combustion with a protective atmosphere in the hearth of the furnace.

Closest to the proposed technical sushi is a gas-fired low-oxidation heating furnace with aerodynamic separation of the oxidation and reduction zones, containing a working chamber under the collector with secondary air nozzles and burners with burner tunnels having a protrusion above the tunnel edge 2.

The installed burners provide gas displacement with air at "(, 5, the

most create a protective zone in the lower part of the furnace (in the zone of placement of metal blanks).

The other side wall (opposite to the burner tunnels) is rounded to rotate and change the flow direction.

 flue gases of incomplete combustion, and in the upper zone there are a number of pipes from the common collector for supplying secondary air for their donations, and to create a high temperature of the flue gases in the upper

IQ zone of the working chamber of the furnace.

Claims (2)

The disadvantages of this furnace are the imperfect organization of mixing the products of incomplete combustion with secondary air and the afterburning, which allows for intensive mixing and rapid completion of the afterburning process, this negatively affects the heat exchange in the furnace. Further, as a result of the movement of flue gases in the working chamber of the furnace, part of the oxidizing gases from the afterburning zone get into the heating zone, which leads to disruption of the metal heating mode in a protective environment - metal loss due to oxidation. The purpose of the invention is to improve the heat exchange in the furnace and create a stable separation of gas flows between zones. The goal is achieved by the fact that in a gas-fired low-oxidation heating furnace with aerodynamic separation of the oxidation and reduction zones containing a working chamber under the collector with secondary air nozzles and a burner with burner tunnels with a ledge above the crater tunnel, the height of the ledge is 0.6- The 0.7 crater diameter of the burner tunnel and the hearth width is 4-5 crater diameters. The drawing shows a furnace, a longitudinal section. The furnace has in the lower part of the side wall of the burner 1, burner tunnels 2, which have a protrusion 3 above the crater tunnel, a working chamber 4 with heating and afterburning zones, below 5, where the workpieces 6 are located. In addition, there is a collector in the upper part of the rear wall of the furnace 7 with nozzles 8, with swirling devices 9 installed in them, and a chimney 10 in which a recuperator is installed 11. The furnace works as follows. A mixture of natural gas and primary air flow with a coefficient of air flow, 5, is burned in tunnel 2 of burner 1. Products of incomplete combustion (protective atmosphere), exit from tunnel 2 fall into working chamber 4 and move along the lower heating zone, where the hearth 5 heated billet 6. Then, the flue gases, by smooth rotation of the rear wall, rise along the arch into the afterburning zone, where they are burned with secondary air coming from the collector 7 through nozzles 8. To accelerate and improve the mixing at the ends of nozzles 8, vortexes 9, which provide more complete combustion of combustible components of flue gases in the initial part of the afterburning zone, which improves the heat exchange of the furnace. In order not to disturb the heating of the metal in the protective / environment associated with metal loss due to oxidation, the protrusion 3 made above the crater of the burner tunnel 2 has a limiting value of (0.6-0.7) dT and a limiting value of width hearth 5 equals (4-b) d, where d ,. - diameter of the crater of the burner tunnel. If these optimal values are violated, the aerodynamics of the separation of oxidative and protective atmospheres in the working chamber of the furnace occurs. Thus, the process and temperature regimes are carried out by two-stage combustion of combustible gases in the furnace volume of the furnace working chamber and, further, the combustion products are directed through the chimney 10 and the heat exchanger 11 to the atmosphere. The proposed furnace for low-oxidation heating allows to achieve high technical and economic indicators by improving heat exchange conditions and due to simplicity of design and reliable operation, stable separation of gas streams between heating and afterburning zones, Formula of the invention zones, containing a working chamber, under, a collector with secondary air nozzles and burners with burner tunnels having a protrusion on d. crater tunnel, In order to improve heat exchange in the furnace and create a stable separation of gas flows between the zones, the height of the protrusion is 0.6-0.7 diameter of the crater of the burner tunnel, and the hearth width is 4-5 diameters of the crater. Sources of information taken into account in the examination 1. Oxidation and decarburization of steel. Ed. Vashchenko A.I. M., “Metallurgists, 1972, p. 192-193. 2. Forging and stamping production, 1975, No. 1, p. 22-24. eleven