US3380410A - Burner apparatus - Google Patents

Description

April 30, 1968 c, V E, JR 3,380,410

BURNER APPARATUS Filed Sept. 7, 1966 FIG; INVENTOR C. R. VENABLE,JR. FIG. 2

ATTORNEYS United States Patent 0 3,380,410 BURNER APPARATUS Charles R. Venable, Jr., Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed Sept. 7, 1966, Ser. No. 577,664 1 Claim. (Cl. 110-97) ABSTRACT OF THE DISCLOSURE Burner apparatus comprises a hollow, tubular, horizontally disposed refractory lined chamber having planar lower interior side and bottom walls in the vicinity of 'a flame impingement baffle downstream of the burning zone in said chamber which bafile comprises a plurality of stacked cylindrical elements supported by said planar interior side and bottom walls and being supported by frictional engagement between said elements the axes of which are parallel to the major axis of the burner chamber.

This invention relates to an improved burner apparatus. In one aspect, a fuel burner comprises a tubular burner chamber having a fluid pervious impingement baflle therein. -In another aspect, a hydrocarbon fuel burner comprises a horizontally disposed burner chamber having therein a flame impingement baffle comprising a plurality of tubular elements. In another aspect, a fuel burner comprises a horizontally disposed burner chamber having therein a flame impingement baffle comprising 'a plurality of cylindrical elements, the axes of which are parallel to each other and to the axis of the burner chamber.

Numerous sources of combustion energy, for example, low B.t.u. hydrocarbons, process off gas streams, etc., are often disposed of as waste for the reason that they burn only under very severe conditions. In other instances, low quality hydrocarbon fuels are often only partially consumed in burners, hot blast stoves, furnaces and the like, The uncombusted fuel is in many instances vented as flue gas without recovering the energy which would be realized by the combustion thereof.

I have found that the degree of combustion of low quality fuels can be improved by conducting the combustion in a novel apparatus.

It is therefore one object of this invention to provide an improved burner apparatus for the combustion of fuels. It is another object of this invention to provide an apparatus for burning low quality fuels. It is yet another object of this invention to improve the degree of combustion of low quality fuels.

Other aspects, objects and several advantages of this invention will be apparent to one skilled in the art from a study of this disclosure, the drawing and the appended claim.

In accordance with one embodiment of this invention, low quality fuels such as, for example, process off-gas streams, low B.t.u. hydrocarbon stocks, etc., which burn only with some difficulty under severe conditions, are burned in a horizontally disposed tubular burner having therein a fluid pervious flame impingement refractory bafiie immediately downstream of the combustion zone. The bafiie receives and accumulates heat from combustion that takes place in the combuston zone and transfers this heat to the uncombusted low quality constituents which are either derived from the feed or produced in the combustion zone upstream of the haflie. Heat is transferred from the baflie to the remaining uncombusted materials promoting the combustion thereof with a consequent improvement in the overall degree of combustion.

3,380,410 Patented Apr. 30, 1968 The concept of this invention will be better understood by reference to the drawings, of which FIGURE 1 is a cross-sectional view of a burner which can be employed within the concept of this invention, FIGURE 2 is an axial cross-section of the burner showing the impingement bafile and FIGURE 3 is an expanded cross-sectional view of the fluid pervious baflle of this invention.

Referring now to the drawings, FIGURE 1 is a crosssectional planar illustration of 'a fuel burner in which the concept of this invention can be employed. Low quality combustible fuel such as flue or waste gas or diflicultly combustible low B.t.u. hydrocarbon mixtures is preferably employed as feed to burner nozzle 2 by way of conduit 1. However, any suitable combustible fuel, for ex ample, hydrocarbons having from 1 to 20 carbon atoms can be employed. Air is drawn into the burner by way of conduit 11 and is preheated by passage through conduits 5 which surround the burner. The air having been preheated enters the burning chamber 16 by way of outlet 9 at which point it is admixed with fuel entering the system from nozzle 2. The mixture is burned in chamber 16 and hot combustion products contact fluid pervious impingement baflie 7 after which they exit the burner by way of conduit 10. These hot combustion products after leaving the burner can be employed for any desired heating purpose such as, for example, solids drying, steam production, etc.

The furnace can comprise an outer metallic shell surrounding the periphery of the burner and providing structural support for the refractory material contained therein. Outer insulating layer 4 composed of fire brick or other suitable high temperature refractory material minimizes heat loss to the atmosphere and surrounds air preheating conduit 5. Inner refractory layer 6 defines the combustion chamber, further insulates the system and conveys heat to air preheater 5. Fluid pervious refractory impingement baffle 7 comprises a plurality of the discrete tubular elements .12 having passages therethrough. These elements are composed of any suitable refractory material capable of withstanding the flame temperatures within the burner. Suitable refractory materials in this application are, for example, fire clay, high alumina, silicon carbide, high purity magnesia, stabilized zirconia, zircon, mullite, and other refractories commonly used for burner block applications.

FIGURE 2 is a cross-sectional view of the interior of the furnace showing the honeycomb structure of the presently preferred fiuid'pervious impingement bafiie of this invention. The majority of the interior wall of the burner 6 is constructed of fire brick being partially replaced by wedge brick 15 in the vicinity of the impingement b'alile. This construction provides a linear inclined wall 7 on either side of the lower burning interior surface which more adequately accommodates the preferred orientation of cylindrical elements 12 which are the presently preferred structural elements of which the baffle is comprised. A linear horizontal lower support for the battle assembly 7 is preferably provided as a ledge or threshold immediately underlying the baffle. The construction of ledge 13 can comprise any suitable refractory material such as cut wedge brick similar to lateral supports 15 or castable refractory as illustrated.

It is only necessary within the concept of this invention that the baffle be comprised of a plurality of refractory elements which can be assembled to form a fluid pervious impingement baffle having relatively high surface area and being of minor axial extent without the necessity of cementing or otherwise attaching individual elements to adjacent elements. Of course, these elements can be physically attached to each other although an advantage of the presently preferred embodiment of this invention is that such structure is not required.

Although the presently preferred element configuration is cylindrical as illustrated due to ease of construction, desirable surface to volume ratios, ease of assembly and the durability of the resulting bafiie, numerous other shapes can be employed. Suitable cross-sectional configurations are, for example, rectangular, triangular, etc., although they need not be geometric.

FIGURE 3 is a cross-section showing the interior burner wall 6, the baffle assembly 7 of a plurality of tubular elements while having passages therethrough 8. Lower support ledge 13 of said castable refractory is also illustrated.

In operation, it is desirable that fluid pervious bathe 7 be located sufficiently downstream of fuel injection nozzle 2 so that most of the relatively combustible fuel is burned before contacting the leading face of b'afiie 7. The remaining uncombusted fuel then contacts heated baffle 7 which transfers suflicient heat to fuel contacting the baffle surface to promote its combustion. Depending on fuel composition, fuel-air ratios and flow rates, the temperature of bafiie 7 will usually be within the range of from about 1800 F. to about 2800 R, which temperature is suflicient to substantially increase the degree of combustihon of relatively noncombustible materials found in low quality fuels. Such fuels are, for example, off-gas from reactors used to make furnace type carbon black, off-gas from the regenerator in a fluid catalytic cracking unit, top gas from blast furnaces, waste gases from open hearth furnaces, 'and similar gases.

Numerous variations and modifications of the concept of this invention will be apparent to one skilled in the art in view of the foregoing disclosure, the drawings and the appended claim to this invention, the essence of which is that there is provided an apparatus for burning fuels comprising a horizontally disposed tubular burner chamher having therein a fluid pervious refractory impingement baffle.

I claim:

1. Burner apparatus comprising a hollow, tubular, horizontally disposed refractory lined burner chamber having fiuid hydrocarbon fuel inlet means at a first axial extremity for injecting said fuel into said chamber, air inlet means at said first axial extremity for injecting air into said chamber, outlet means at the other axial extremity for permitting the passage of combustion products from said chamber, fluid pervious refractory impingement baifie means positioned within said chamber for receiving heat from the combustion of said fuel upstream of said bafiie and transmitting said heat to uncombusted fuel contacting said bafile to burn s'aid uncombusted fuel, the lower interior side and bottom walls of the burner in the vicinity of the baffle being planar, the baffle comprising a plurality of discrete cylindrical elements loosely stacked upon the planar interior side and bottom walls and being supported by frictional engagement between the elements, the axes of the elements being parallel to the axis of the chamber.

References Cited UNITED STATES PATENTS 1,080,368 12/1913 Reagan 11097 1,485,967 3/1924 Duncan 110-97 2,906,368 9/ 1959 Nelson.

FOREIGN PATENTS 2,781 1914 Great Britain.

JAMES W. WESTHAVER, Primary Examiner.

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