Combustion – Process of combustion or burner operation – Flame shaping – or distributing components in combustion zone
Reexamination Certificate
1999-12-21
2001-02-20
Yeung, James C. (Department: 3743)
Combustion
Process of combustion or burner operation
Flame shaping, or distributing components in combustion zone
C431S012000, C431S181000, C431S187000
Reexamination Certificate
active
06190158
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject of the present invention is a process for the combustion of a fuel in a burner of the type comprising an injector, which injector includes at least an inner first oxidizer feed passage, an intermediate fuel feed passage externally surrounding the first oxidizer feed passage, and an outer second oxidizer feed passage externally surrounding the fuel feed passage.
2. Description of the Related Art
The invention applies in particular to the supply of heat in processes for the production of materials.
Many processes for the production of materials, such as glass and ferrous or non-ferrous metals, involve heating steps in which burners of the aforementioned type are used with, for example, methane as the fuel and oxygen as the oxidizer.
The flames produced by these burners must comply with certain constraints.
For example, in the glass production processes, molten glass is generally transferred between two successive steps of the process by means of feeders. In such a feeder, the glass lying near the walls of the feeder tends to cool much more rapidly than the glass further away from these walls. Consequently, it is desirable to be able to reheat the periphery of the glass without reheating the core of the latter, in order to maintain an approximately homogeneous temperature profile in the sections of the molten material.
For this purpose, burners of the aforementioned type are placed in the walls of these transfer feeders. Unfortunately, the known combustion processes using burners of the aforementioned type do not always make it possible to adjust the length of the flames produced in order to satisfactorily heat the sections of the molten material fed.
Such is the case for the process described by document EP-A-763,692, in which the velocities of the fuel and of the internal oxygen exiting the injector are relatively high.
Similarly, the known combustion processes do not make it possible to comply with the constraints relating to the concentrations of the oxidizing species CO and O
2
, these being related to the length of the flame, at the exit of the burners placed near the baths of molten materials in metal production processes.
The object of the invention is to solve these problems by providing a combustion process for a burner of the aforementioned type, making it possible for the length of the flame and the concentrations of chemical species in it, especially CO and O
2
, to be finely adjusted.
SUMMARY OF THE INVENTION
For this purpose, the subject of the invention is a process for the combustion of a fuel in a burner of the aforementioned type, characterized in that the fuel feed passage is supplied so that the velocity of the fuel exiting this passage is between approximately 1 and 15 m/s.
According to particular methods of carrying out the process according to the invention, it may comprise one or more of the following characteristics, taken separately or in any technically possible combination:
the fuel feed passage is supplied so that the velocity of the fuel exiting this passage is greater than approximately 5 Am/s;
the first oxidizer feed passage and the fuel feed passage are supplied so that the ratio R of the velocity of the oxidizer exiting the first oxidizer feed passage to the velocity of the fuel exiting the fuel feed passage is greater than approximately 3;
the first oxidizer feed passage and the fuel feed passage are supplied so that the ratio R is less than approximately 20;
the first oxidizer feed passage and the fuel feed passage are supplied so that the ratio R is less than approximately 10;
the second oxidizer feed passage is supplied so that the velocity of the oxidizer exiting this second passage is between approximately 0.1 and 50 m/s and preferably between approximately 1 and 5 m/s;
the first and second oxidizer feed passages are supplied so that less than 50%, and preferably less than approximately 20%, of the total oxidizer flow passes through the first oxidizer feed passage;
a peripheral passage of the injector is supplied with air, which peripheral passage externally surrounds the second oxidizer feed passage;
the first and second oxidizer feed passages are supplied with oxygen having a purity of greater than 80%; and
the fuel feed passage is essentially supplied with a gaseous hydrocarbon, especially with methane or butane.
The subject of the invention is also a use of a process as defined above for making it possible, by modifying the proportion of the total oxidizer flow passing through the first oxidizer feed passage, to adjust the length of a flame for heating a molten-glass transfer feeder in the production of glass.
Furthermore, the subject of the invention is a use of a process as defined above for making it possible, by modifying the proportion of the total oxidizer flow passing through the first oxidizer feed passage, to adjust the oxidizing power of a heating flame produced in the production of metal.
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patent: 4933163 (1990-06-01), Fischer et al.
patent: 5178533 (1993-01-01), Collenbusch et al.
patent: 5295816 (1994-03-01), Kobayashi et al.
patent: 5743723 (1998-04-01), Iatrides et al.
patent: 5904475 (1999-05-01), Ding
patent: 0 643 262 (1995-03-01), None
patent: 0 763 692 (1997-03-01), None
Legiret Thierry
Rio Laurent
Burns Doane , Swecker, Mathis LLP
L'Air Liquide, Societe Anonyme pour l'Etude et l'
Yeung James C.
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