WO1999061839A1 - A boiler arrangement and a method of burning oil - Google Patents

A boiler arrangement and a method of burning oil Download PDF

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Publication number
WO1999061839A1
WO1999061839A1 PCT/SE1999/000890 SE9900890W WO9961839A1 WO 1999061839 A1 WO1999061839 A1 WO 1999061839A1 SE 9900890 W SE9900890 W SE 9900890W WO 9961839 A1 WO9961839 A1 WO 9961839A1
Authority
WO
WIPO (PCT)
Prior art keywords
flue gas
air
fan
burner
conduit
Prior art date
Application number
PCT/SE1999/000890
Other languages
French (fr)
Inventor
Kaj-Ragnar Loqvist
Original Assignee
Wedab Wave Energy Development Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to SE9801840-1 priority Critical
Priority to SE9801840A priority patent/SE9801840L/en
Priority to SE9900664A priority patent/SE9900664D0/en
Priority to SE9900664-5 priority
Priority to SE9901114-0 priority
Priority to SE9901114A priority patent/SE9901114D0/en
Application filed by Wedab Wave Energy Development Ab filed Critical Wedab Wave Energy Development Ab
Publication of WO1999061839A1 publication Critical patent/WO1999061839A1/en

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23DBURNERS
    • F23D11/00Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
    • F23D11/001Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space spraying nozzle combined with forced draft fan in one unit
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23LSUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L5/00Blast-producing apparatus before the fire
    • F23L5/02Arrangements of fans or blowers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2202/00Fluegas recirculation
    • F23C2202/30Premixing fluegas with combustion air
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2900/00Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/09002Specific devices inducing or forcing flue gas recirculation

Abstract

A boiler (11) has a conventional oil burner (12). Flue gas is recirculated from the stack to the burner and mixed with atmospheric air to form the combustion air. Subpressure is provided in the fan (22, 31) of the burner and the flue gas is drawn into the fan and mixed with the air in the fan. The flue gas is cooled in a cooler (16) before being mixed with the air. The emission of nitrogen oxides will be extremely low.

Description

A boiler arrangement and a method of burning oil Field of invention

This invention relates to a method of burning oil by atomising it and burning it with air and recirculated flue gas. It relates also to a boiler arrangement

Background of the invention and prior art

The flue gas from conventional oil burners is normally very clean today as to the amount of carbon monoxide, hydrocarbons, and flue dust. The content of nitrogen oxides (NOxor NOX), however, is usually still high. GB-B 1 464 169 describes a method for reducing air pollution agents in the flue gas. Particularly, a method is described that reduces the amount of the nitrogen oxides by recirculating flue gas. A small amount of the air is mixed with recirculated flue gas but most of the combustion air is added at various points without being mixed with flue gas. This method makes the apparatus very complicated and probably also difficult to adjust.

GB-A 2 259 567 describes a method for reducing the amount of nitrogen oxides in a natural gas burner by recirculating flue gas and mixing it with the combustion air before ejecting it in the burner. The flue gas is additionally heated before the mixing.

Object of invention

It is an object of the invention to reduce the nitrogen oxides in a simple and safe way that can be applied to a simple conventional oil burner.

Brief description of the invention

The recirculated flue gas and the air are mixed to a combustion air that comprises at least 80% of the total mass flow of combustion air. The flue gas is cooled before being mixed with the air. The cooling doubles the effect of the flue gas recirculation. Preferably, the flue gas is sucked into a mixing chamber for flue gas and air. This mixing chamber can be an inlet chamber in a fan housing so that the air and flue gas mix in the fan.

Brief description of the drawings

Figure 1 is a side view of a boiler with an oil burner. Figure 2 is a fragmentary front view seen as indicated by the arrows 2-2 in figure 1 and partly in section.

Figure 3 is a section through a somewhat modified burner. Figure 4 shows enlarged a detail from fig 3. Figure 5 is a section through another modified burner.

Detailed description of preferred embodiments

Figure 1 shows a boiler 1 1 with a conventional oil burner 12. A conduit 13 lead from the stack 14 to the burner 12 and there is a cooler 16 in the conduit 13 for cooling the flue gas that is recirculated from the stack to the burner 12. There is also a valve 17 in the conduit 13, by which the flow of recirculated flue gas can be adjusted.

Figure 2 shows the burner 12 on a larger scale. It comprises an electric motor 20 which has a shaft 21 that rotates a rotor 22 of a fan and the rotor of an oil pump 23. The fan housing has been denoted by 31. The conduit 13 leads to the interior of the fan rotor 22 and ends with a funnel 24. The inlet for atmospheric air is through a housing 25 with a non-illustrated valve by which the inlet area for air can be adjusted. Since the air inlet is restricted, there will be a reduced pressure inside the fan rotor which sucks flue gas through the conduit 13 so that air and a minor amount of flue gas will mix in the fan and form the combustion air. The amount of flue gas can be adjusted by the valve 17. Normally, there should be 10-20 % flue gas by weight in the combustion gas. A secondary burning may be arranged, but at least 80% of the total of the atmospheric air should be supplied as this primary combustion air.

Figure 3 shows the burner in a section and it shows the atomising nozzle 27 and the high- pressure tube 28 that lead from the oil pump 23 to the nozzle 27. At the very front end of the burner, there is also a turbulator 29 that gives the combustion air a swirling motion. In this figure, the flue gas inlet has been modified from the one in figures 1 and 2, and it is indicated by numeral 30 in the figure. The modified inlet 30 is shown on a larger scale in figure 4. The conduit 13 leads to holes 32,33 in the fan housing 31 and vanes 34,35 make an ejector that draws flue gas into the fan housing. Fig 4 shows still another way of drawing the flue gas through the conduit 13 and into the burner. On the pressure side of the fan, there is an annular ejector 36. The ejector 36 has an annular inlet chamber 37 with an inlet nipple 38 to which the conduit 13 is to be coupled. In this modified design, the tube 39 form a mixing chamber for the atmospheric air and the flue gas. In the designs according to figure 2 and 3, the fan housing 31 forms the mixing chamber.

Normally, about 15 % of the flue gas is recirculated and the recirculated gas should be cooled in the cooler 16 to as low a temperature as possible since the emission of nitrogen oxides will be lower the lower the temperature is. The temperature should preferably not exceed 50 C. A normal temperature of 30-40 °C can be reached when a non-expensive and simple cooler is used.

Claims

Claims
1. A method of burning oil by atomising the oil and burning it with air and recirculated flue gas, characterised in that the flue gas is cooled and the air and the recirculated flue gas are then mixed to a combustion air that comprises at least 80 % by weight of the total mass flow of combustion air.
2. A method according to claim 1 , characterised in that the flue gas is sucked into a mixing chamber (31,39) for air and recirculated flue gas.
3. A method according to claim 2, characterised in that atmospheric air and the flue gas is sucked into a fan (22,31) so that the air and the flue gas mix in the fan.
4. A method according to any one of the preceding claims, characterised in that the flue gas is cooled to a temperature below 50 ┬░C.
5. A boiler arrangement comprising a boiler (11), a stack (14) from the boiler, an oil burner (12), and a conduit (13,16,17) from the stack to the burner for recirculation of flue gas, characterised by a cooler (16) in the conduit (13,16.17) for cooling the flue gas.
6. A boiler arrangement according to claim 5, characterised in that the oil burner comprises a high pressure oil pump, a nozzle for atomising the high pressure oil from the pump, and a fan for blowing combustion air to pass around the nozzle.
7. A boiler arrangement according to claim 6, characterised in that the conduit (13,16,17) for flue gas ends in a sub-pressure area in the fan so that the flue gas is drawn through the conduit (13,16,17). A boiler arrangement according to claim 6, characterised by an ejector (36) in a passageway in the burner downstream of the fan, to which the flue gas conduit (13,16,17) is coupled.
PCT/SE1999/000890 1998-05-25 1999-05-25 A boiler arrangement and a method of burning oil WO1999061839A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
SE9801840-1 1998-05-25
SE9801840A SE9801840L (en) 1998-05-26 1998-05-26 Automatic NOx reduction
SE9900664A SE9900664D0 (en) 1999-02-21 1999-02-21 NOx ejector
SE9900664-5 1999-02-21
SE9901114A SE9901114D0 (en) 1999-03-24 1999-03-24 Reduction of Nox
SE9901114-0 1999-03-24

Publications (1)

Publication Number Publication Date
WO1999061839A1 true WO1999061839A1 (en) 1999-12-02

Family

ID=27355924

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1999/000890 WO1999061839A1 (en) 1998-05-25 1999-05-25 A boiler arrangement and a method of burning oil

Country Status (1)

Country Link
WO (1) WO1999061839A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017068407A1 (en) * 2015-10-19 2017-04-27 Bertelli & Partners S.R.L. Method for reducing harmful gas emissions from a gas-fired sealed combustion chamber forced-draught boiler using flue gas recirculation and according boiler

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US718554A (en) * 1902-06-14 1903-01-13 William George Waring Method of extracting zinc.
GB1464169A (en) * 1974-01-11 1977-02-09 Aqua Chem Inc Pollutatnt reduction with selective gas stack recirculation
US4023921A (en) * 1975-11-24 1977-05-17 Electric Power Research Institute Oil burner for NOx emission control
EP0384277A2 (en) * 1989-02-24 1990-08-29 HEIMAX Heizkessel GmbH Method and combustion installation for the reduction of nitrogen oxide formation during the combustion of fossil fuels
US5092761A (en) * 1990-11-19 1992-03-03 Exxon Chemical Patents Inc. Flue gas recirculation for NOx reduction in premix burners
GB2259567A (en) * 1991-09-11 1993-03-17 Mark Iv Transportation Tech Boiler with low NOX combustion of gaseous fuels
US5413477A (en) * 1992-10-16 1995-05-09 Gas Research Institute Staged air, low NOX burner with internal recuperative flue gas recirculation
EP0687854A1 (en) * 1994-06-13 1995-12-20 N.V. Acotech S.A. Burner with recirculation of exhaust gas

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US718554A (en) * 1902-06-14 1903-01-13 William George Waring Method of extracting zinc.
GB1464169A (en) * 1974-01-11 1977-02-09 Aqua Chem Inc Pollutatnt reduction with selective gas stack recirculation
US4023921A (en) * 1975-11-24 1977-05-17 Electric Power Research Institute Oil burner for NOx emission control
EP0384277A2 (en) * 1989-02-24 1990-08-29 HEIMAX Heizkessel GmbH Method and combustion installation for the reduction of nitrogen oxide formation during the combustion of fossil fuels
US5092761A (en) * 1990-11-19 1992-03-03 Exxon Chemical Patents Inc. Flue gas recirculation for NOx reduction in premix burners
GB2259567A (en) * 1991-09-11 1993-03-17 Mark Iv Transportation Tech Boiler with low NOX combustion of gaseous fuels
US5413477A (en) * 1992-10-16 1995-05-09 Gas Research Institute Staged air, low NOX burner with internal recuperative flue gas recirculation
EP0687854A1 (en) * 1994-06-13 1995-12-20 N.V. Acotech S.A. Burner with recirculation of exhaust gas

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017068407A1 (en) * 2015-10-19 2017-04-27 Bertelli & Partners S.R.L. Method for reducing harmful gas emissions from a gas-fired sealed combustion chamber forced-draught boiler using flue gas recirculation and according boiler
EA036581B1 (en) * 2015-10-19 2020-11-26 Бертелли Энд Партнерс С.Р.Л. Method for reducing harmful gas emissions from a gas-fired sealed combustion chamber forced-draught boiler and boiler so obtained
US10851991B2 (en) 2015-10-19 2020-12-01 Bertelli & Partners S.R.L. Method for reducing harmful gas emissions from a gas-fired sealed combustion chamber forced-draught boiler and boiler so obtained

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