US2398654A - Combustion burner - Google Patents

Description

April 1946- l. LUBBOCK ET AL 2,398,654

COMBUSTION BURNER Filed June 50, 1941 E j v U 3 lnvznrors; Isaac Lubbock Patented Apr. 16,1946

COMBUSTION BURNER- f Isaac Lubbock and Frederick Great St. Helens, London,

Petroleum Company Limto The Anglo-Saxon ited, London, England,

Britain James Batter-shill, v England, assignors a company of Great Application June so, 1941,Serlal No. 400,548

In Great 3 Claims.-

This invention relates to an improved process and apparatus for the continuous generation of gases by reaction between air and liquid or pulveruient combustible material. The object of the invention is to provide a more effective means whereby large quantities of the combustible material can be burnt in a zone of comparatively small volume under continuous conditions such'as may be required for combustion turbines or for other gas utilising appliances. Thus the invention has in view rates of combustion which may exceed about one hundred pounds of, say, fuel oil per hour per cubic foot of combustion space.

In accordance with the invention the combustible material in liquid or pulverulent form, is sprayed into a chamber and in the course of passage therethrough to an offtake for the gaseous reaction products it is first caused to undergo preliminary thermal decomposition, which may be described as pre-oxidation, with a-comparatively small quantity of air whereupon it is caused to encounter, or be enveloped in or drawn into a vortex of main primary air which, generally speaking, is moving backwards, i. e. in the pposite direction to the flow of the primary reaction products so that combustion is then substantially effected in a burning zone proper between where the primary air is admitted into the chamber and the place of spraying in the combustible material.

Preferably the secondary airwith which the sprayed combustible material initially reacts is introduced at or near the spray nozzle or atomizer in a. swirling state produced by any usual arrangement of inclined vanes or tangential admission ports. The chamber space may be somewhat enlarged at or about the zone where the primary reaction occurs.

The primary air may be definitely introduced through a ring of ports provided with swirling vanes to form a strong vortex within the chamber, the axis of this vortex being coincident with the axis of the chamber, and the ring of ports being disposed at a substantial distance from the end of the chamber where the conbustible material is sprayed in. The axial position of this ring of admission ports for the primary air requires fairly close determination, having regard to the various conditions obtaining, in order to secure the most satisfactory operation. It has been ascertained in an experiment that the distance of the ring of ports from the sprayer or atomizer should be somewhere about twice the greatest diameter of the chamber.

I It will be understood that it is within this Britain January 24, 1940 chamber space between the primary air admission ports and the sprayer that'the intermediate. and

vention additional air may be admitted to inter- 1 7 mix with the reaction products after they have passed from the combustion zone. This .addi tional air will be introduced in such manner that it will be entrained substantially intothe centre core of the stream of reaction productswhere the temperature is usually highest. In order to secure this result it is preferred to admit this further air through tubes spaced around the circumference of the chamber and radially disposed with their outlets close tothe centre of the chamher. I In the preferred arrangement, the air required for the primary andsecondary supplies and for the subsequent dilutionis admitted under pres sure into a space between the combustion cham-- her and an outer co-axiai cylinder. However, individual air boxes may be provided if desired in order to supply each section;

It has been ascertained that by of the invention, involving a progressive form of combustion through intermediate stages of pre-oxidation, the issuing gases are devoid of unburnt or partially burnt substances and. that they have the characteristic sweet odour associated with hydroxylation.

The accompanying drawing shows diagrammatically the preferred embodiment of the invention, Figure 1 being a longitudinal sectional elevation of the apparatus, Figure 2 a section on the line 2--2 of Figure .1, and Figure 3 a section on the line 3-3 of Figure 1.

Referring to the drawing, l indicates the combustion chamber casing and 2 the cylindrical casing of an air supply duct in which the casing I is co-axially mounted, Combustible material in liquid or pulverulent form is introduced into the chamber through the-atomiser 3. The

secondary air, taken under pressure, from the air.

supply duct, is admitted through a swirler 4.

The primary reaction (pm-combustion) between the combustible material and the secondary air occurs in the enlarged z'one' indicated at into the chamber the process 5. A jet I I, is provided between the enlarged zone 5 and fuel atomizer 3 as shown.

Primary air from the air supply duct is admitted into the chamber through the swirler 6 whereby the air is formed into a vortex which, moving backwards, i. e. from right to left in the drawing, envelops the reaction products coming from the primar reaction zone 5 and brings about their combustion in the zone indicated at I.

The stream of reaction products from the combustion zone passing forwards through the chamher, is diluted by entraining into its core additional air admitted through the radially disposed tubes 8, Further diluting air is admitted through the holes 9, after which the gases pass to the outlet l0.

What we claim is:

l. A fuel combustion apparatus comprising an elongated combustion chamber, said chamber comprising from one end to the other, a mixing zone, a jet, an enlarged pre-combustion zone, a combustion zone, a dilution zone and a discharge outlet; an air supply means surrounding said chamber; a fuel nozzle and secondary air supply means at the end of said chamber adjacent said mixing zone; a primary air supply swirler around said combustion zone for introducing primary air into said combustion zone; and dilution air ducts projecting radially into said di1u-' tion zone and terminating adjacent its center.

'2. The apparatus'of claim 1 wherein the distance' between said fuel nozzle and said primary air swirler is equal approximately to twice the greatest diameter of said pro-combustion zone of saidchamber.

3. A fuel combustion apparatus comprising an elongated combustion chamber, said chamber comprising from one end to the other, a mixing zone, a jet, an enlarged pre-combustion zone, a combustion zone, a dilution zone and a discharge outlet; an air supply means surrounding said chamber; means to supply air to said chamber under pressure; a fuel nozzle and secondary air supplymeans at the end of said chamber adjacent said mixing zone; a primary air supply swirler around said combustion zone for introducing primary air into said combustion zone; and dilution air ducts projecting radially into said dilution zone and terminating adjacent its center.

ISAAC LUBBOCK. FREDERICK JAMES BA'I'I'ERSHILL.

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