Heater and method of operation
AssigneeLummus Technology Inc.
InventorsPeter R. Ponzi, Francesco Bertola, Robert J. Gartside
Life of this patent
Estimating the term…
Abstract
A furnace, firing pattern and method of operating a heater that employs a combination of hearth burners and wall burners for the cracking of hydrocarbons is described. The firing pattern leads to improvements in the uniformity of the coil metal temperatures and vertical heat flux profiles over the firebox elevation. The hearth burners operate with a stoichiometric excess of air while the wall burners operate with less than the stoichiometric amount of air.
Claims35
A method of operating a heater including a radiant heating zone comprising a lower portion including a hearth burner section and an upper portion including a wall burner section;
- at least one tubular heating coil located in the radiant heating zone;
- the hearth burner section comprising a plurality of hearth burners located adjacent to the bottom hearth for firing in the radiant heating zone;
- and the wall burner section comprising a plurality of wall burners located adjacent to opposing walls, the method comprising:
- introducing to the wall burner section a first air and fuel mixture having less than the stoichiometric quantity of air for combustion of fuel introduced to the wall burner section, and
- introducing to the hearth burner section a second air and fuel mixture having greater than the stoichiometric quantity of air for combustion of fuel introduced to the hearth burner section,
- the overall quantity of air introduced to the hearth burner section and wall burner section being at least a stoichiometric quantity.
A method of operating a heater including a radiant heating zone comprising a lower portion including a hearth burner section and an upper portion including a wall burner section;
- at least one tubular heating coil located in the radiant heating zone;
- the hearth burner section comprising a plurality of hearth burners located adjacent to the bottom hearth for firing in the radiant heating zone;
- and the wall burner section comprising a plurality of wall burners located adjacent to the opposing walls, the method comprising:
- introducing a first air and fuel mixture to a the wall burner section, the first air and fuel mixture having less than the stoichiometric quantity of air for combustion;
- introducing a second air and fuel mixture to the hearth burner section in a direction generally parallel to the length of the heating coil, the second air and fuel mixture having more than the stoichiometric quantity of air for combustion;
- and
- combusting the fuel and air in the radiant heating zone, wherein air and a portion of the fuel introduced at the wall burner section combusts at a first rate and a portion of the air introduced at the hearth burner section combusts with a portion of the fuel introduced at the wall burner section at a second combustion rate that is slower than the first combustion rate.
A heater comprising:
- a. a radiant heating zone comprising a lower portion including a hearth burner section and an upper portion including a wall burner section;
- b. at least one tubular heating coil located in the radiant heating zone;
- c. the hearth burner section comprising a plurality of hearth burners located adjacent to the bottom hearth portion, the hearth burner section being configured to fire with greater than stoichiometric amounts of air;
- and
- d. the wall burner section comprising a plurality of wall burners, the wall burners being configured to fire along opposing walls in the radiant heating zone with less than stoichiometric amounts of air.
- the heater being configured to operate with at least about 10 % excess of air.
(canceled)
A firing pattern for a gas heater having a lower hearth burner section and an upper wall burner section, the firing pattern comprising operating the wall burner section with less than the stoichiometric quantity of air for combustion and feeding additional air to the hearth burner section to result in an overall net excess of air being fed to the heater.
A method of operating a heater including a radiant heating zone comprising a lower portion including a hearth burner section and an upper portion including a wall burner section;
- at least one tubular heating coil located in the radiant heating zone;
- the hearth burner section comprising a plurality of hearth burners located adjacent to the bottom hearth for firing in the radiant heating zone;
- and the wall burner section comprising a plurality of wall burners located adjacent to the opposing walls, the method comprising:
- introducing a first air and fuel mixture comprising no more that about 85% of the stoichiometric quantity of air for combustion to the wall burner section, the first air and fuel mixture having less than the stoichiometric quantity of air for combustion;
- introducing a second air and fuel mixture comprising between 20% to 100% more than the stoichiometric quantity of air for combustion to the hearth burner section in a direction generally parallel to a heating coil, the second air and fuel mixture having more than the stoichiometric quantity of air for combustion;
- and
- combusting the fuel and air in the radiant heating zone, wherein the air and a portion of the fuel introduced at the wall burner section combusts at a first rate and a portion of the air introduced at the hearth burner section combusts with a portion of fuel introduced at the wall burner section at a second combustion rate that is slower than the first combustion rate to reduce the overall combustion rate in the wall burner section of the heater,
- wherein the heater operates with at least about 10% greater than the stoichiometric quantity of air overall.
Dependencies are inferred from the claim text.