Method and device to reduce emissions of nitrogen oxides and increase heat transfer in fired process heaters
AssigneeXRG Technologies, LLC
InventorsErwin Platvoet, Matthew Martin
Life of this patent
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Abstract
A method and device for reducing emissions of nitrogen oxides and for increasing heat transfer in a fired process heater is disclosed herein. The invention relates generally to the combustion of fuel using some proportion of air as the oxidant which leads to the production of oxides of nitrogen, and more particularly to a method and device that reduces the production of nitrogen oxides from combustion, promotes the appropriate distribution of temperature to reduce fouling of the process tubes in a fired heater, and increases the efficiency of heat transfer to the same process tubes.
Claims24
A device for reducing emissions of nitrogen oxides and for increasing heat transfer in a fired process heater, said fired process heater comprising a radiant section having a plurality of process tubes and a burner, said device comprising:
- a fuel and flue gas entrainment unit positioned remote from the burner of the fired process heater, the entrainment unit comprising:
- a fluid outlet, a fluid inlet, and a fluid flow path intermediate of said fluid inlet and said fluid outlet;
- said entrainment unit fluid outlet configured to attach to said fired process heater upstream of one or more convection tubes such that said entrainment unit fluid flow path is in fluid communication with said radiant section of said fired process heater;
- an inlet section of reducing diameter, a mixing section of constant diameter, and an exit section of expanding diameter;
- a fuel injector configured to issue fuel at subsonic, sonic, or supersonic velocity into said entrainment unit fluid flow path, wherein the fuel is entrained with flue gas from said radiant section of said fired process heater in said entrainment unit fluid flow path to form an entrained flue gas and fuel mixture, which flows through said entrainment unit fluid flow path to said radiant section of said fired process heater;
- ductwork positioned remote from the burner of the fired process heater, the ductwork comprising a fluid outlet, a fluid inlet, and a fluid flow path intermediate of said fluid inlet and said fluid outlet;
- said ductwork fluid outlet connected to said entrainment unit fluid inlet such that said ductwork fluid flow path is in fluid communication with said entrainment unit flow path;
- said ductwork fluid inlet configured to attach to said fired process heater such that said ductwork fluid flow path is in fluid communication with the flue gas from said radiant section of said fired process heater;
- and
- wherein the entrainment unit and the ductwork form a closed circuit regarding fluid flow from the radiant section of the fired process heater, through the ductwork fluid flow path, the entrainment unit fluid flow path, and back to the radiant section of the fired process heater.
A device for reducing emissions of nitrogen oxides and for increasing heat transfer in a fired process heater, said fired process heater comprising a radiant section having a plurality of process tubes and a burner, said device comprising:
- a fuel and flue gas entrainment unit positioned remote from the burner of the fired process heater, the entrainment unit comprising a fluid outlet, a fluid inlet and a fluid flow path intermediate of said fluid inlet and said fluid outlet;
- said entrainment unit further comprising an inlet section of reducing diameter, a mixing section of constant diameter, and an exit section of expanding diameter;
- wherein fuel is entrained with flue gas from the radiant section of the fired process heater in the fluid flow path of the entrainment unit to form an entrained flue gas and fuel mixture, which flows from the fluid outlet of the entrainment unit to a fluid inlet of a venturi eductor;
- ductwork positioned remote from the burner of the fired process heater, the ductwork comprising a fluid outlet, a fluid inlet and a fluid flow path intermediate of said fluid inlet and said fluid outlet;
- said ductwork fluid outlet connected to said entrainment unit fluid inlet such that said ductwork fluid flow path is in fluid communication with said entrainment unit flow path;
- said ductwork fluid inlet configured to attach to said fired process heater such that said ductwork fluid flow path is in fluid communication with the flue gas from said radiant section of said fired process heater;
- the venturi eductor comprising a fluid outlet, the fluid inlet and a fluid flow path intermediate of said fluid inlet and said fluid outlet;
- said venturi eductor fluid inlet connected to said entrainment unit fluid outlet such that said venturi eductor fluid flow path is in fluid communication with said entrainment unit fluid flow path;
- said venturi eductor fluid outlet attached to said fired process heater upstream of a plurality of convection tubes such that said venturi eductor fluid flow path is in fluid communication with said radiant section of said fired process heater;
- said venturi eductor comprising an inlet section of reducing diameter, a mixing section of constant diameter, and an exit section of expanding diameter;
- said venturi eductor configured to use a secondary fluid to increase the fluid flow through said flue gas entrainment unit;
- wherein the entrained flue gas and fuel mixture and the secondary fluid flow from the fluid outlet of the venturi eductor to the radiant section of the fired process heater;
- and
- wherein the entrainment unit, the ductwork, and the venturi eductor form a closed circuit regarding fluid flow from the radiant section of the fired process heater, through the ductwork fluid flow path, the entrainment unit fluid flow path, and the venturi eductor fluid flow path, and back to the radiant section of the fired process heater.
Dependencies are inferred from the claim text.