Electrically heated burner

Patent metadata

Field	Value
Publication number	US-2016348901-A1
Application number	US-201615235580-A
Country	US
Kind code	A1
Filing date	Aug 12, 2016
Priority date	Feb 14, 2013
Publication date	Dec 1, 2016
Grant date	—

Abstract

A burner includes an electrically powered heater configured to output heat energy to a burner portion configured to contact a fuel stream or a combustion reaction supported by the fuel stream.

First claim

What is claimed is:

1 . A burner, comprising:
a fuel and oxidant source configured to provide a fuel and oxidant stream that includes a range of fuel concentrations to support a combustion reaction; a body disposed adjacent to the fuel and oxidant stream and configured to exchange heat energy with the fuel and oxidant stream; and an electrically powered heater arranged to convey at least a portion of electrically generated heat to the body.

2 . The burner of claim 1 , wherein the electrically powered heater is arranged to conduct a majority of electrically generated heat to the body.

3 . The burner of claim 1 , wherein the body comprises a vortex generator.

4 . The burner of claim 1 , wherein the body comprises a perforated flame holder body; and
wherein being disposed adjacent to the fuel and oxidant stream comprises being disposed to receive the fuel and oxidant stream into a plurality of perforations defined by the perforated flame holder body.

5 . The burner of claim 1 , wherein the electrically powered heater includes an electrical resistance heating element.

6 . The burner of claim 3 , wherein the vortex generator is configured to generate vortices aligned circumferentially around the fuel and oxidant stream.

7 . The burner of claim 1 , wherein the body comprises at least one non-flammable log.

8 . The burner of claim 1 , further comprising:
a thermostat operatively coupled to the electrically powered heater, the thermostat including a temperature sensor and an electronic controller operatively coupled to the temperature sensor; wherein the thermostat is configured to cause the electrically powered heater to maintain the body at a selected temperature.

9 . The burner of claim 8 , wherein the electronic controller is configured to cause the electrically powered heater to raise the temperature of the body to the selected temperature before causing a fuel valve to open to provide the fuel and oxidant stream; and
wherein the electronic controller is configured to cause the fuel valve to open to provide the fuel and oxidant stream after the temperature of the body reaches the selected temperature.

10 . The burner of claim 8 , wherein the selected temperature is preselected to be equal to or greater than an autoignition temperature of the fuel.

11 . The burner of claim 8 , wherein the thermostat is configured to increase a rate of heating by the electrically powered heater when a rate of fuel flow is reduced, and to decrease the rate of heating by the electrically powered heater when the rate of fuel flow is increased.

12 . The burner of claim 1 , wherein the electrical heater includes at least a portion embedded in the body.

13 . The burner of claim 12 , wherein the body defines one or more hollow passages formed within the body; and
wherein the electrical heater is carried within the one or more hollow passages.

14 . The burner of claim 12 , wherein at least a portion of the body forms a conical surface; and
wherein the electrical heater is wrapped around the conical surface.

15 . The burner of claim 1 , wherein the body defines one or more grooves formed in a surface of the body; and
wherein the electrical heater is disposed in the one or more grooves.

16 . The burner of claim 1 , further comprising:
an electronic controller operatively coupled to the electrically powered heater, the electronic controller including a timer; and a fuel flow rate sensor operatively coupled to the electronic controller; wherein the electronic controller is configured to respond to the timer to cause the electrically powered heater to dissipate heat at a duty cycle inversely proportional to a rate of fuel flow sensed by the fuel flow rate sensor.

17 . The burner of claim 1 , further comprising an igniter.

18 . The burner of claim 17 , wherein the igniter is configured to be turned off after ignition.

19 . The burner of claim 17 , wherein the electrically powered heater is configured to at least selectively remain powered during combustion.

20 . The burner of claim 17 , wherein the igniter is separate and distinct from the electrically powered heater and the body.

21 . A method of increasing a turndown ratio of combustion, comprising:
outputting fuel into a combustion volume; admitting air into the combustion volume; allowing the fuel to at least partially entrain the air in the combustion volume to form a fuel and air jet having a range of mixtures; supporting a flame holder adjacent to the fuel and air jet in a position predetermined to promote vortex formation in the mixture; igniting the fuel and air mixture to form a combustion reaction; and electrically heating the flame holder to maintain stable ignition of the fuel and air mixture within the vortices promoted by the flame holder.

22 . The method of combustion of claim 21 , wherein maintaining ignition includes at least intermittently transferring electrically-generated heat from the flame holder to the vortices.

23 . The method of combustion of claim 21 , wherein at least a majority of the electrically-generated heat flows to the turbulent portion of the mixture via a body of the flame holder.

24 . The method of combustion of claim 21 , further comprising starting the combustion reaction with an igniter.

25 . The method of combustion of claim 21 , wherein supporting a flame holder includes supporting a hollow cylindrical refractory body peripheral to a fuel nozzle and an air source; and
wherein supporting a flame holder adjacent to the fuel and air jet in a position predetermined to promote vortex formation in the mixture includes supporting the hollow cylindrical refractory body to receive at least a portion of the fuel and air jet through the hollow portion of the cylinder and supporting a vortex-formation surface at an end of the flame holder perpendicular to a nominal direction of fuel and air flow.

26 . The method of combustion of claim 25 , wherein the vortex-formation surface is configured to cause toroidal vortices to form such that hot combustion products are recycled from the combustion reaction to the fuel and air jet.

27 . The method of combustion of claim 25 , wherein allowing the fuel to at least partially entrain the air in the combustion volume to form a fuel and air jet having a range of mixtures further comprises adjusting at least one of a fuel flow rate and an air flow rate.

28 . The method of claim 21 , wherein electrically heating the flame holder includes passing an electric current through an electrically powered heater.

29 . The method of claim 21 , wherein electrically heating the flame holder includes passing an electric current through the flame holder.

30 . A control system for controlling dynamics of a flame, comprising:
a source of electric current; an electrically heated flame holder immersed in the flame and coupled to the source, wherein the source induces electric current flow therethrough; a temperature-responsive current controller coupled to the source and the electrically heated flame holder to adjust the electric current flow through the electrically heated flame holder toward a predetermined temperature of the electrically heated flame holder.

31 . The control system for controlling dynamics of a flame of claim 30 , wherei

Assignees

• Clearsign Comb Corp

Inventors

• Karkow Douglas W
• Colannino Joseph
• Wiklof Christopher A

Classifications

• F23D11/00

  Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space · CPC title

• F23D11/38

  Nozzles; Cleaning devices therefor · CPC title

• F23D1/00 Primary

  Burners for combustion of pulverulent fuel · CPC title

• F23D11/44

  Preheating devices; Vaporising devices · CPC title

• F23D14/22

  with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other · CPC title