Burner and method for processing oxidizable materials
Burner assembly for use in industrial heating and melting applications of material susceptible to oxidation at elevated temperatures is comprised of a flow passage of oxidant surrounded by an annular flow passage of fuel whereby the oxidant is substantially contained inside the fuel layer up to at least 5 oxidant nozzle diameters downstream of the burner outlet in order to minimize contact between the oxidant and the furnace load.
1. A process for heating a charge of material comprising:
providing a charge of material to be heated,
combusting a fuel and an oxidant by using a burner comprising at least two co-axial conduits wherein the oxidant is supplied by a first conduit and the fuel is supplied by a second conduit and the second conduit surrounds the first conduit thereby shielding oxidant from the charge and providing a fuel rich zone adjacent the charge,
heating the charge by radiant and convective transfer of heat from the combustion to the charge, and;
recovering heated material.
2. The process of claim 1 wherein the charge comprises at least one member selected from the group consisting of aluminum, iron, lead, nickel, tin and zinc; and the charge is heated to an elevated temperature.
3. The process of claim 1 wherein the charge is provided to a member selected from the group consisting of a rotary, reverbatory and a stack melting furnace.
4. The process of claim 1 wherein the charge is provided to a single pass furnace.
5. The process of claim 1 wherein the charge is provided to a double pass furnace.
6. The process of claim 1 wherein the fuel comprises at least one member selected from the group consisting of gaseous, liquid and solid fuels.
7. The process of claim 1 wherein the oxidant comprises oxygen enriched air or oxygen.
8. The process of claim 7 wherein the fuel nozzle has an angle of about 7 to 20 degrees with respect to a burner axis that extends longitudinally.
9. The process of claim 7 wherein the oxidant nozzle has an angle of less than about 9 degrees with respect to the burner axis that extends longitudinally.
10. The process of claim 1 wherein the burner has dimensions that satisfy: [(1+x)/x] 1/2 <R/r<[(5+x)/x] 1/2 where R is the radius of a fuel nozzle and r is the radius of an oxidant nozzle and x is the ratio of oxidant to fuel.
11. The process of claim 1 wherein the concentration of oxidant adjacent to the charge is less than about 1.0% by volume.
12. A process for heating a charge of material comprising:
providing a charge of material to be heated,
combusting a fuel and an oxidant by using a burner wherein the oxidant is supplied to the burner in a manner such that the fuel substantially surrounds the oxidant thereby shielding oxidant from the charge and providing a fuel rich zone adjacent the charge, heating the charge by radiant and convective transfer of heat from the combustion to the charge, and;
recovering heated material and wherein the charge is provided to a double pass furnace.
13. A process for heating a charge of material comprising:
providing a charge of material to be heated,
combusting a fuel and an oxidant by using a burner having a co-axial configuration wherein the oxidant is supplied to the burner through a first conduit that is completely surrounded by a second conduit that supplies fuel to the burner thereby shielding oxidant from the charge and providing a fuel rich zone adjacent the charge, heating the charge by radiant and convective transfer of heat from the combustion to the charge, and;
recovering heated material.