Catalytic flameless combustion apparatus with extremely low pollutant emission and combustion method

Patent metadata

Field	Value
Publication number	US-10859261-B2
Application number	US-201716093932-A
Country	US
Kind code	B2
Filing date	Apr 6, 2017
Priority date	Apr 14, 2016
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A catalytic flameless combustion apparatus has a fuel inlet, a combustion-supporting gas inlet, a gas premixer, a combustion plate, an igniter, a gas deflector, a flameless combustion cavity, a catalyst filled in the flameless combustion cavity, a gas collection chamber and an exhaust port. The method for starting the catalytic flameless combustion apparatus includes initially combusting and heating the flameless combustion cavity and the catalyst filled therein with low power flame; and then increasing flow velocity and switching to high power flame for conducting catalytic flameless combustion. The catalytic flameless combustion apparatus can be used for various non-solid fuel combustion and heat extraction processes.

First claim

We claim:

1. A catalytic flameless combustion apparatus, comprising:
a first housing having an upper end and a lower end closed by a plate, wherein at least one combustion-supporting gas inlet and at least one fuel inlet are disposed about the lower end of the first housing;
a gas premixer disposed inside the first housing above the combustion-supporting gas inlet and the fuel inlet;
a combustion plate disposed inside the first housing above the gas premixer;
wherein a space between the lower end of the first housing and the combustion plate defines a gas premixing cavity, and the gas premixer resides in the gas premixing cavity;
an igniter disposed inside the first housing above the combustion plate;
a gas deflector having a tubular body with a lower opening and an upper opening;
a second housing that defines a flameless combustion cavity and has a single opening opposed to the upper opening of the gas deflector; and
a catalyst disposed inside the second housing,
wherein the lower opening of the gas deflector is connected to the upper end of the first housing, and
wherein the upper opening of the gas deflector is flush with the single opening in the second housing or extends into the flameless combustion cavity through the single opening in the second housing.

2. The catalytic flameless combustion apparatus according to claim 1 , wherein the gas premixer is in the shape of a sheet, a rod, or a honeycomb monolith, and is connected to an inner wall of the first housing,
wherein, during operation, the gas premixer causes changes in a flow direction of a combustion-supporting gas and in a flow direction of a fuel gas and thereby premixing the combustion-supporting gas and the fuel gas in the premixing cavity,
wherein the combustion plate has a planar structure having pores or through holes that allow the premixed gas to pass through the combustion plate,
wherein the through holes have a diameter or slit width of 0.01-10 mm and the combustion plate has a thickness of 0.1-1000 mm.

3. The catalytic flameless combustion apparatus according to claim 1 , wherein
the catalyst is fixedly supported by a bracket affixed to inner wall of the second housing flameless combustion cavity.

4. The catalytic flameless combustion apparatus according to claim 1 , wherein an area of the opening in the second housing is 1.01-20 times of an area of the upper opening of the gas deflector.

5. The catalytic flameless combustion apparatus according to claim 1 , further comprising a third housing having one or more exhaust ports, wherein the third housing is disposed about the second housing, forming a gas collection chamber between an outer wall of the seconding housing and the inner wall of the third housing.

6. The catalytic flameless combustion apparatus according to claim 1 , further comprising a fixing bracket for affixing the second housing.

7. The catalytic flameless combustion apparatus according to claim 5 , wherein sectional area of the one or more exhaust ports is larger than an area of the upper opening of the gas deflector.

8. The catalytic flameless combustion apparatus according to claim 5 , further comprising a heat exchanger disposed inside the second housing, on an outer wall of the second housing, or on an outer wall of the third housing, wherein the heat exchanger is a shell-and-tube heat exchanger, a finned type heat exchanger, or a plate type heat exchanger.

9. A method for operating the catalytic flameless combustion apparatus of claim 1 , comprising:
introducing an oxygen-containing combustion-supporting gas through the combusting-supporting gas inlet and a gaseous fuel through the fuel gas inlet at an air coefficient of 1.01-2.5;
mixing air and the fuel gas in the gas premixing cavity to form a premixed gas;
controlling a linear velocity of the premixed gas to between a tempering linear velocity and a flame blowoff linear velocity according to tempering linear velocity and flame blowoff linear velocity;
igniting the premixed gas using the igniter;
heating the catalyst disposed in the flameless combustion cavity to above 600° C.;
increasing the linear velocity of the premixed gas to above the flame blowoff linear velocity to extinguish a flame;
carrying out flameless combustion of the premixed gas on the catalyst; and
discharging a tail gas through the one or more exhaust ports in the third housing.

10. The method according to claim 9 , wherein the combustion-supporting gas is air, oxygen, or an oxygen-containing mixed gas with oxygen content of 1-99.9 vol % other than air, and wherein the gaseous fuel is natural gas, coal gas, and liquefied petroleum gas, gasoline, diesel fuel, kerosene, alcohol, or methanol.

11. The catalytic flameless combustion apparatus according to claim 1 , wherein the catalyst comprises a carrier and a metal oxide active component, wherein the carrier is ceramics, quartz, spinel, carborundum, stainless steel with fibrous, granules, or a honeycomb monolith, wherein the metal oxide active components is aluminum oxide, cerium oxide, magnesium oxide, lanthanum oxide, titanium oxide, ferric oxide, manganese oxide, silicon oxide, sodium oxide, copper oxide, nickel oxide, powder blue, platinic oxide, palladium oxide, ruthenium oxide, rhodium oxide, silver oxide, or a mixture thereof, wherein the metal oxide active component has a mass percentage of 0.1%-85% of the catalyst.

12. The method according to claim 1 , wherein the catalyst comprises a carrier and a metal oxide active component, wherein the carrier is ceramics, quartz, spinel, carborundum, stainless steel with fibrous, granules, or a honeycomb monolith, wherein the metal oxide active components is aluminum oxide, cerium oxide, magnesium oxide, lanthanum oxide, titanium oxide, ferric oxide, manganese oxide, silicon oxide, sodium oxide, copper oxide, nickel oxide, powder blue, platinic oxide, palladium oxide, ruthenium oxide, rhodium oxide, silver oxide, or a mixture thereof, wherein the metal oxide active component has a mass percentage of 0.1%-85% of the catalyst.

Assignees

• Dalian Inst Chem & Physics Cas

Inventors

• Li Weizhen
• Chen Zhiqiang
• Zhang Jingcai
• Wu Chuntian
• Zhang Tao

Classifications

• F23D14/18

  using catalysis for flameless combustion · CPC title

• F23D14/70

  Baffles or like flow-disturbing devices · CPC title

• F23C2700/046

  generating heat by heating radiant bodies · CPC title

• F23C3/002 Primary

  the chamber having an elongated tubular form, e.g. for a radiant tube · CPC title

• F23D2203/104

  Grids, e.g. honeycomb grids · CPC title