US3765609A

US3765609A - Emulsion burner

Info

Publication number: US3765609A
Application number: US00258429A
Authority: US
Inventors: G Robic
Original assignee: Elf Union
Current assignee: Elf Antar France; Elf Union
Priority date: 1971-06-01
Filing date: 1972-05-31
Publication date: 1973-10-16
Anticipated expiration: 1990-10-16
Also published as: ZA723709B; DE2226621B2; AU452025B2; ES403365A1; FR2141404A1; CH553378A; CA945471A; BE784143A; JPS5245064B1; DE2226621C3; DE2226621A1; NL7207344A; NL167233B; BR7203515D0; AU4292372A; IT959013B; LU65435A1; NL167233C; RO61045A; FR2141404B1

Abstract

Sludges or liquid wastes to be incinerated and containing small particles, a combustible liquid such as fuel oil, and an atomization fluid under pressure, are conveyed through separate passages within a central body and admitted in gyratory motion into a frontal chamber so as to form an emulsion which is discharged through a central nozzle orifice around a stationary cone-point pintle. Sludges or liquids containing large particles which can attain several millimeters in diameter are conveyed with an atomization fluid through other passages and admitted in gyratory motion into a separate annular region around the emulsion chamber for subsequent discharge in a ring-shaped pattern which surrounds the emulsion, thus guiding and stabilizing the flame produced while preventing any clogging of the central nozzle orifice.

Description

United States Patent [191 Robic Oct. 16, 1973 EMULSION BURNER Primary Examiner-Lloyd L. King 75 Inventor: Gabriel Robic, Paris, France Kerkam [73] Assignee: Elf Union S.A., Paris, France 57] ABSTRACT [22] Filed: May 1972 Sludges or liquid wastes to be incinerated and contain- [21] AppL No; 258,429 ing small particles, a combustible liquid such as fuel oil, and an atomization fluid under pressure, are conveyed through separate passages within a central body [30] Forelgn Apphcamm Pnomy Data and admitted in gyratory motion into a frontal cham- June 1, France her so as to form an emulsion is discharged through a central nozzle orifice around a stationary [52] US. Cl. 239/705 cone point 1 [51] Int. Cl. 05b 7 l0 Sludges or liquids containing large particles which can [58] held of Search 139/402 attain several millimeters in diameter are conveyed with an atomization fluid through other passages and admitted in gyratory motion into a separate annular [56] References Cited region around the emulsion chamber for subsequent UNITED STATES PATENTS discharge in a ring-shaped pattern which surrounds l,934,837 11/1933 Zulver 239/400 the emulsion, thus guiding and stabilizing the flame 2,267,154 12/1941 Hopkins 239/00 produced while preventing any clogging of the central 3,383,049 5/1968 Guerin 239/400 nozzle orifice 3,713,588 1/1973 Sharpe 239/400 5 Claims, 3 Drawing Figures sum 10$ 3 PATENIEDncI 16 I975 Pmmrmncnems, I V 8,765,609 I SHEET 30F 3 EMULSION BURNER This invention relates to an emulsion burner which is primarily but not exclusively intended for the incineration of sludges or charged liquids of different kinds and in particular bottom sediments of tanks containing hydrocarbons or residual effluents of refining.

In emulsion burners of known types, there is formed an intimate mixture of a liquid fuel such as fuel oil, an oxidizing or carburizing gas which is usually air or vapor with or without entrainment of solid particles and finally an additional liquid essentially constituted by water charged with soluble or insoluble elements capable of reacting with certain combustion products which are formed. In particular, there is one known type of burner in which the emulsion is formed directly at the burner nozzle itself within a mixing chamber, the relative proportion of the different phases of this emulsion being regulated by means of a single control element which can be displaced along the axis of the burner.

The present invention is concerned with another type of burner which, while retaining the principle of formation of an emulsion and especially a fuel, a liquid and a gas or vapor, makes it possible by virtue of a structural modification of the apparatus to contemplate the possibility of burning atomized sludges or charged liquids including solid particles having different sizes and at least in some cases large dimensions which can attain several millimeters in diameter. Within the scope of an application of this type, the aim of the invention is to prevent clogging of the burner with sludge particles while also removing any danger of explosion which could result from a prolonged temperature build-up of the volatile products contained in the sludges temselves or mixed with the fuel, especially if these sludges constitute bottom sediments of refinery tanks. Another object of the invention is to permit the construction of a simple and inexpensive apparatus which does not call for the use of any mechanical moving part, with the result that the burner is of particularly rugged design and is'easy to maintain.

To this end, the burner under consideration essentially comprises a central body provided with longitudinal passages for the separate admission of the constituents of an emulsion into a frontal chamber which is delimited near the burner outlet by a cover connected to the central body, said emulsion being formed of a combustible liquid, of sludges or liquids charged with small particles and of a fluid under pressure for the atomization of said sludges, an orifice formed at the center of said cover for the discharge of emulsion from said chamber, a cone-point pintle mounted in front of said orifice in a fixed position with respect to the central body, an outer sleeve forming around the cover an annular region into which open other passages provided within the body for the admission of sludges or liquids charged with large particles and the same or another gaseous atomization fluid, said sludges being expelled from the annular region in a ring-shaped pattern which surrounds the emulsion as it is discharged from the frontal chamber.

In accordance with a particular feature of the burner under consideration, fin segments of helical shape or elements having similar effects are mounted within the frontal chamber and in the annular region in front of the passages for the admission sludges and atomization vapor or gaseous fluid so as to generate a gyratory flow motion which improves the conditions of this atomization process.

According to a further characteristic feature, the outer sleeve is surrounded by a casing having a wide opening in front of the frontal chamber and joined to a duct for the admission of an oxidizing or carburizing gaseous fluid which is identical with or different from the atomization fluid. Preferably, and in one particular mode of application of the invention, the oxidizing gas and the gaseous atomization fluid are constituted by air under pressure in which the proportions for the atomization of sludges charged with small particles, sludges charged with large particles and the combustion process are respectively 5 percent, 15 percent and percent of the total air supplied. In another mode of application, the atomization fluid can be constituted by steam or another gas, whether mixed or not with air under pressure or with another gas.

By virtue of these arrangements, the sludges or liquids charged with small particles are admitted into the frontal chamber so as to form within said latter an emulsion with the liquid fuel which is usually fuel oil and with the atomization gas, said sludges being derived in particular from the bottom sediments of tanks for the storage of hydrocarbons. The burner under consideration makes it possible in particular to introduce these sludges into the burner within a portion of this latter which is located as far as possible in the downstream direction, that is to say as close as possible to the combustion zone itself, in order to prevent said sludges from overheating as they pass towards the frontal chamber and from introducing explosion hazards. Furthermore and in accordance with an essential feature of the invention, the sludges or liquids charged with large particles are atomized in a ring-shaped pattern around the emulsion without passing through the frontal chamber and therefore without any danger of clogging its discharge orifice, the effect of the ringshaped pattern formed at the outlet of the burner being also to ensure efficient stabilization of the flame since this latter is guided within a kind of envelope of slightly conical shape which is propelled by virtue of a suitable choice of pressure and delivery of the atomization air or steam at a velocity which is higher than the velocity of said flame. The quantity of motion of this latter is accordingly increased to an appreciable extent, thereby achieving an even greater improvement in the efficiency of the burner.

Further characteristic features of a burner as con 'structed in accordance with the invention will become apparent from the following description of one exemplified embodiment which is given by way of indication without any implied limitation, reference being made to the accompanying drawings, in which FIG. 1 is a diagrammatic view in elevation and in partial section of the burner under consideration FIG. 2 is a longitudinal sectional view to a larger scale showing the head or front portion of the burner of FIG. 1

FIG. 3 is a sectional view of an alternative form of construction of the burner head shown in FIG. 2.

As can be seen from FIG. 1, the burner which is illustrated comprises a central body 1 having an extension towards the rear, that is to say towards the right-hand side of the drawing and at the end remote from the region in which the flame is produced, in the form of a tubular duct 2 within which extend parallel to its axis admission tubes such as 3, 4 and 5 for different fluids which are to undergo simultaneous combustion. In the figure, only the tube 3 is shown in full lines whilst the two other tubes are represented diagrammatically by chain-dotted lines in order not to complicate the drawing unduly. Said tubes are joined directly to the body 1 at one end and pass out of the duct 2 at the other end after traversing a closure plate 6 which is attached to the rear end of said duct by means of screws 7. The

different tubes

3, 4 and 5 are connected externally of the burner to supply stations (not shown) which make it possible in particular to supply to the apparatus a liquid fuel such as a fuel oil or more generally a suitable hydrocarbon, and sludges or charged liquids to be incinerated which contain particles of different sizes and are derived from bottom sediments of storage tanks or constitute refining wastes. The duct 2 is also provided with an inlet-connection 9 which serves to admit within the interior a gaseous fluid and especially air or a vapor which serves to disperse part of the above-mentioned sludges in an atomized spray pattern in the manner which will be explained below.

The burner comprises a cylindrical sleeve 10 which surrounds the duct 2 and is fixed on the body 1, provision being made for an annular space 11 between the internal surface of said sleeve and the external surface of said duct. This space is closed at the rear end of the burner by an end-plug 12 which is mounted on the cut 2 in leak-tight manner and is coupled by means of an inlet-connection 13 to a source of gaseous fluid which is preferably identical with the fluid admitted into the burner through the connector 9 but can be different and in particular consist of steam, the intended function of this fluid being to ensure that the remaining sludges to be incinerated are atomized as they are discharged from the apparatus. The sleeve 10 is provided at the other end nearest the region of discharge of products to be ignited, with a shaped component 14 whose design function will also be explained below with reference to FIG. 2. Finally, the apparatus as a whole is completed by means of an outer casing 15 which in turn delimits with the external surface of the sleeve 10 an annular region 16 closed at the rear end by a leaktight end-plug 17 which is adapted to cooperate with said sleeve. Said annular region is coupled by means of an inlet-connection 18 to a high-delivery source of an oxidizing or carburizing gaseous fluid which serves to maintain the burner flame, said casing 15 being provided with a wide opening 19 substantially at the level of the burner head through which the products to be ignited are expelled. The casing 15 is fixed in position with respect to the burner head by means of external lugs 20 which are secured by means of screws 21 to a supporting frame 22.

FIG. 2 illustrates in greater detail the construction of the burner head, the operation of which can thus be more readily understood. There is again shown in this figure the central body 1 which is connected at the rear end to the duct 2 and the

tubes

3, 4 and 5 which are mounted within the interior of said duct and through which the products to be ignited are conveyed to the burner. The tube 3 in particular is screwed into the rear end of the body 1 and preferably reserved for the purpose of admitting into the burner a liquid fuel such as fuel oil, for example, which passes through the body 1 via an axial longitudinal passage 23 formed in said body, then flows out at the center and in front of the body 1 into a frontal chamber 24 or socalled emulsion chamber which is closed at the front end by means of a cover 25 screwed onto a threaded annular shoulder 25a of the body 1.

The tube 4 also opens into the same emulsion chamber 24 by means of a passage 26 formed in the body 1 so as to introduce and mix within the chamber a first sludge to be incinerated which contains particles of relatively small diameter or, in other words, particles which do not have an excessively uneven size distribution. This sludge is vigorously mixed with the fuel oil which is admitted through the passage 23, on the one hand by means of helical-fin segments 27 which are fixed on the body 1 in front of the outlet of the passage 26 so as to induce gyratory or rotational flow motion and, on the other hand, by means of a complementary admission of gaseous fluid under pressure which usually consists of either air or steam, thereby producing a spray discharge of the mixture of fuel oil and of sludge and forming a finely divided emulsion. This gaseous fluid is admitted directly through the inletconnection 9 of the duct 2 and passes into the chamber 24 through other inclined passages 28 each provided at the end which opens into the chamber with fin segments 29 which are similar to the segments 27. The emulsion thus formed is discharged from the chamber 24 through the cover 25 which is provided with a central orifice 30, the quality of the emulsion being ensured by mounting in the axis of said orifice a conepoint pintle 31 provided with lateral slots 32 and rigidly fixed in position within the chamber 24 by means of a member 33 having helical grooves 33a and forming a diffuser which is in turn fixed on an annular shoulder 33b of the body 1.

In accordance with the invention, the burner as thus constructed permits not only the combustion of sludges containing fine particles which are emulsified within the frontal chamber 24 as explained in the foregoing, but also sludges which contain particles of substantially larger diameter of the order of a few millimeters and which consequently cannot be treated inthe same manner as the sludges just mentioned by reason of the immediate danger of choking or clogging of the burner within the chamber 24, especially between the pintle 31 and the discharge orifice 30. To this end, the sludges of the second class just mentioned are conveyed via the tube 5 and pass through the body 1 via other inclined passages 34 which, in this case do not open into the chamber 24, but into an annular space 35 delimited on the one hand by the external surface of the cover 25 and on the other hand by the internal surface of the shaped component 14 which forms an extension of the sleeve 10. Pins 36 are also provided in front of the extremities of the passages 34 in order that the sludges admitted into the space 35 should be endowed with rotational fluid motion. Within this space, said sludges are also atomized by the gaseous fluid, in practice either air or steam, which comes from the intermediate region 11 between the duct 2 and the sleeve 10, this region being in turn connected to said space 35 by means of passages 37 which are formed through the body 1 and in front of which are mounted fins 38. As a result of efficient agitation and mixing of the sludge and air, a ring of atomized mixture which completely surrounds the emulsion of the other sludge derived from the chamber 24 can be produced at the outlet of the burner through an annular slit 39 which is formed between the space 14 and the body 25. The mixture can then be ignited and combustion is maintained by means of the air which is delivered at a high rate through the inletconnection 18 to the region 16 (shown in FIG. 1) the flame produced by the emulsion is accordingly guided by the slightly conical envelope formed by the sludges which consist of large atomized particles and are discharged through the annular slit 39.

In the alternative embodiment shown in FIG. 3, the greater part of the arrangements contemplated in the example hereinabove described with reference to FIG. 2 have again been adopted. However, in this case, the tube 3 which serves to convey the liquid fuel to the burner nozzle is replaced by two separate tubes 3a and 3b which meet upstream of the burner nozzle in front of the pintle slots 32 within an intermediate chamber 3c. As in the previous embodiment, the tube 3a serves to supply the burner with a suitable liquid fuel on the other hand, the tube 3b is intended to supply another liquid to be burned such as, for example, a highly vola tile or hazardous product such as gasoline, acetone or the like which it is desired to destroy at the same time as the sludges or charged liquids. Said product is then intimately mixed with the fuel inside the chamber 36, this process being immediately followed by ignition of the mixture at the precise level of the burner outlet and at the same time as the emulsified sludges, thereby forestalling any explosion hazard which might otherwise arise if the same product were conveyed in a different manner and in particular mixed with air upstream of the burner nozzle. It should be noted that the product itself can be sufficiently combustible to permit the possibility of replacing the flow through the tube 3a which is accordingly stopped in this instance.

The emulsion burner which is thus constructed permits the incineration of hydrocarbon sludges or other sludges containing particles of appreciable diameter without any attendant danger of clogging of the burner, at the same time as other products to be destroyed. In particular, the apparatus circumvents any danger of explosion of volatile products contained either in. the sludges which are supplied to the burner or in the additional products to be burned since all these constituents are introduced in regions located as far downstream as possible and, in particular, immediately before the region in which the combustion of said constituents takes place. The quantities of air which are necessary can be essentially variable according to the nature of the products to be incinerated but are preferably chosen in the ratios of 80 percent in the case of the combustion air derived from the region l6, percent in the case of ,the air which comes from the region 11 and serves to atomize the large-particle sludges and finally 5 percent in the case of the air which produces the ternary emulsion within the chamber 24. The air thus performs simultaneously the function of pneumatic transporting agent and means for finely dividing the treated sludges. In consequence, this burner is particularly well suited to the incineration of storage tank sediments and hydrocarbon wastes derived from refineries since it permits practically total combustion of these latter. In addition, the apparatus is particularly simple, especially by virtue of the fact that it does not comprise any mechanical moving part. This makes it both very rugged and very easy to use, the necessary adjustments being obtained by modifying the pressure and flow rate of the different fluids within the apparatus. The pressure of the gaseous fluid can vary in particular between 400 millibars and 1 bar, depending on the nature of the products to be destroyed.

The invention is clearly not limited solely to the example of construction which has been more especially described with reference to the drawings on the contrary, it extends to all alternative forms. In particular, it is readily apparent that the different passages for con veying fluids through the central body could be distributed and oriented within this latter in a different manner the same could apply to the connections between the passages and the tubes through which these fluids are supplied.

What we claim is:

1. An emulsion burner for the combustion of sludges or charged liquids comprising a central body, longitudi nal passages in said body for the separate admission of the constituents of an emulsion, a frontal chamber connected to said passages adjacent the burner outlet, a cover connected to said central body defining said chamber, said emulsion being formed of a combustible liquid, of sludges or liquids charged with small particles and of a fluid under pressure for the atmoization of said sludges, an orifice at the center of said cover for the discharge of said emulsion from said chamber, a conepoint pintle mounted in front of said orifice in a fixed position with respect to said central body, an outer sleeve forming around said cover an annular region, passages within said body opening into said region for the admission of other sludges or liquids charged with large particles and an atomization fluid, said sludges being expelled from said annular region in a ringshaped pattern surrounding the emulsion as it is discharged from said frontal chamber, a casing surrounding said outer sleeve and having a wide opening in front of said frontal chamber and av duct opening into said casing for the admission of an atomization fluid.

2. An emulsion burner according to claim 1, including fin segments of helical shape mounted within said frontal chamber and in said annular region in front of said passages for the admission of sludges. and said atomization fluid generating a gyratory flow motion and improving atomization.

3. An emulsion burner according to claim 2, said atomization fluid being air under pressure in which the proportions for the atomization of sludges charged with small particles, sludges charged with large particles and the combustion process are respectively 5%, 15% and of the total air supplied.

4. An emulsion burner according to claim 1, wherein said atomization fluid is steam.

5. An emulsion burner according to claim 1, including an intermediate chamber for mixing the combustible liquid immediately before admission into said frontal chamber with a hazardous product to be burned within the sludges.

Claims

1. An emulsion burner for the combustion of sludges or charged liquids comprising a central body, longitudinal passages in said body for the separate admission of the constituents of an emulsion, a frontal chamber connected to said passages adjacent the burner outlet, a cover connected to said central body definIng said chamber, said emulsion being formed of a combustible liquid, of sludges or liquids charged with small particles and of a fluid under pressure for the atmoization of said sludges, an orifice at the center of said cover for the discharge of said emulsion from said chamber, a cone-point pintle mounted in front of said orifice in a fixed position with respect to said central body, an outer sleeve forming around said cover an annular region, passages within said body opening into said region for the admission of other sludges or liquids charged with large particles and an atomization fluid, said sludges being expelled from said annular region in a ring-shaped pattern surrounding the emulsion as it is discharged from said frontal chamber, a casing surrounding said outer sleeve and having a wide opening in front of said frontal chamber and a duct opening into said casing for the admission of an atomization fluid.

2. An emulsion burner according to claim 1, including fin segments of helical shape mounted within said frontal chamber and in said annular region in front of said passages for the admission of sludges and said atomization fluid generating a gyratory flow motion and improving atomization.

3. An emulsion burner according to claim 2, said atomization fluid being air under pressure in which the proportions for the atomization of sludges charged with small particles, sludges charged with large particles and the combustion process are respectively 5%, 15% and 80% of the total air supplied.