METHOD AND APPARATUS FOR TREATING ASPHALTENE BEARING FUELS

Abstract: Apparatus for treating asphaltene bearing fuels, and a method for treating asphaltene bearing fuels. Known apparatus for treating asphaltene bearing fuels suffer from the drawback of not being able to sufficiently reduce the size of undesirably large asphaltene particles in heavy fuel oils. The above problem is solved by providing an apparatus comprising a series of closely-packed shearing edges (16, 18) which contact and condition liquid flowing thereby. The edges are carried on propellor-shaped articles (14, 26) and mounted on an axial shaft (15) in a conduit (11). Groups (12, 24, 35, 40 and 50) of the articles carrying the shearing edges are provided axially along the shaft. The articles of each group have a unique orientation and configuration relative to the articles of each other group. Fuel oil containing asphaltene particles is flowed along shaft (15). The fuel oil is contacted and conditioned by the shearing edges. The asphaltene particles are reduced to extremely small size, so that they are readily burned in a boiler with reduced particulates in the stack effluent.

Description: "Method and Apparatus for Treating Asphaltene Bearing Fuels" BACKGROUND OF THE INVENTION U.S. Patents 4,109,318 to Hutchins discloses an in-line blender having propellor-like blades of gra¬ duated configuration placed along a central shaft of a flow conduit. The blades form continuous spiral mixing channels which extend well into the center of the con¬ duit. U.S. Patent 4,123,178 to Salzman et al discloses a similar in-line blender. In each of the above patents a number of propellor-like blades are mounted on a central shaft to impart a general swirl-type motion to a liquid travelling therethrough. Reversal of the direction of swirl is recognized as a mixing expedient. Numerous other static devices, usually mixers, are disclosed in the art as contributing some desirable property to a liquid flowing therethrough. See for example, U.S. Patents 4,441,832; 3,582,048; 4,427,030 and the like. Also, in prior art, but not heretofore related to static mixers, is U.S. Patent 4,479,805 to Batra which disclosed the pumping of an asphaltene-bearing oil through a perforated pipe to reduce the particle size of asphaltene particularly when the asphaltene was carried in water-oil emulsions. Notwithstanding the process of Batra, it was found that the variety of asphaltene in oil made still further improvements in asphaltene conditioning desirable in order to reduce the particulate emissions from stack gas. An additional aspect of the commercial background of the invention is the fact that heavy fuel oils have had varying increasing amounts of asphaltene therein and the quantity of quality of asphaltene can vary con¬ siderably shipment-to-shipment. SUMMARY OF THE INVENTION It is a principal object of the invention to pro¬ vide an improved high-intensity apparatus for use in ■ liquid processing. It is a particular object of the invention to pro¬ vide an improved process for reducing the size of unde¬ sirably large asphaltene particles in heavy fuel oils, thereby rendering the oil more suitable for clean com¬ bustion. A further object of the invention is to provide a one-pass process for treating asphaltene-bearing fuel oils to reduce the size of asphaltene particles. A further object of the invention is to provide a process and apparatus which may be varied in con- figuration quickly and inexpensively to meet the requirement of a specific shearing problem presented by various heavy fuels carrying asphaltene of different characteristics. Other objects of the invention will be obvious to those skilled in the art on their reading of this disclosure. The above objects have been achieved by providing a fluid processing element comprising a conduit, the flow path of which is obstructed with stationary shearing edges designed to cause intensive shearing of the liquid being processed. It is also advantageous that the apparatus have a substantial mixing charac¬ teristic to assure that all liquid is treated during passage through the apparatus. The same elements that carry the shearing edges can also act as mixing means. This is particularly true when small sharp-edged blades are used as the shearing means. In the preferred embodiment of the invention, the shearing edges are carried on groups of closely-packed, propellor-like elements. Groups of the elements with similar pitch relative to the fluid flow are spaced at short distances from one another to assure some mixing and that all of the liquid is processed by the blades. The inner wall of the conduit in which the blades are placed are sufficiently close to the other periphery of the blade elements that a substantial amount of flow occurs in helix-like paths formed by the elements. It has been discovered that when heavy fuel oils, e.g. No. 6 and No. 10 oils, are processed through the apparatus of the invention, most asphaltene "particles" are reduced in particle size from their initial size — often 15 to 50 microns— to below 10 microns in average diameter. The desired co inuting action can be achieved in a short length of reactor and in a single pass, a major advance over the shear-processing of asphaltene hereto¬ fore known to the art. In the most advantageous embo¬ diments of the invention, the shearing elements are divided into a variety of processing zones. Some such zones are described below. A flow-orientation zone: These zones provide a swirl to the liquid. Preferably, they are formed of shearing elements. However, because of relatively great spacing, the shearing elements are generally less effective in the flow-orienting zones than in the more compact particle-shear zones. Typically, there are about 1.5 to 3 swirls (i.e. 306° - helical turns) ini¬ tiated per inch of length of the flow-orientation zone when a 1-inch diameter restraining conduit is used. A. particle-shear zone is a relatively compact arrangement of shearing edges, typically about 3.0 to about 6 helical "swirls" initiated per inch when a 1-inch restraining conduit is used. Still another shear type zone is a baffled-shear zone one which provides a baffled-swirl flow path. In a typical arrangement the centerline of the flow path is generally helical but follows a zig-zag pattern. The spacing of the swirl flow paths are about the same as those in the primary particle-shear zone. However the baffled-shear zone serves as an effective particle shearing device but contributes more pressure drop to the system than do the other zones. It is advantageous, but not necessary, to have spaces between zones along the flow path which can be utilized to facilitate change in flow patterns from zone-to-zone. In such spaces it is often desirable to have conduit baffling, as narrowing means, to direct the liquid inwardly toward the shearing elements to avoid any undesirable bypassing. The flow configurations, particularly those which are principally used to achieve the asphaltene comi- nuting action, are desirably formed of small stamped propellors which, when mounted adjacent to one another on a shaft, leave small gaps between propellors, simu¬ lating what would be small V-shaped slits in a one- piece helical element. However, in addition to the slits, it has been found helpful to have the propellors sufficiently irregular (inherent in a stamping process of manufacture for propellors as shown) that the pro- pellor surfaces are somewhat and irregularly offset from one another along what would otherwise be an 5 idealized helical flow path. Of course this offset condition is inherent, and relatively severe, in the baffled-swirl flow path. A typical asphaltene-shearing application according to the invention can include a series of ele- 10 ments mounted in parallel one with the other, each one adapted to handle a proportion only of the total flow of petroleum product depending on the design parameters of a given facility several dozen of the devices may be utilized to condition fuel. 15 One of the problems with conditioning asphaltene- bearing oils such as No. 6 and No. 10 fuel oil is that the term "asphaltene" can refer to material of substan¬ tially different characteristics depending upon the source of petroleum and its treatment after withdrawal 20 from its source. Thus, even within a given fuel ship¬ ment, the "asphaltene" can comprise some very small particles of brittle solids although much of it will be more in the nature of small globules of a pitch-like substance. In any event, it has been found desirable 25 to subject many asphaltene-bearing oils to a much more severe shearing treatment than than disclosed in U.S. Patent 4,479,805 to Batra. However, surprisingly, and probably because of the great variety in asphaltene <2? forms, it has been found that the process described by 30 Batra can be of incremental value in treating asphaltenes when it is used in series with the appara¬ tus newly describe herein. Moreover, the addition of water to the fuel system appears to provide some advan¬ tage in achieving good asphaltene. ILLUSTRATIVE EXAMPLE OF THE INVENTION In this application and accompanying drawings there is shown and described a preferred embodiment of the invention and suggested various alternatives and modifications thereof, but it is to be understood that these are not intended to be exhaustive and that other changes and modifications can be made within the scope of the invention. These suggestions herein are selected and included for the purposes of illustration in order that others skilled in the art will more fully understand the invention and the principles thereof and will be able to modify it and embody it in a variety of forms, each as may be best suited to the condition of a particular case. IN THE DRAWINGS Figure 1 is an exploded perspective view of an apparatus of the invention showing a restraining con¬ duit and the asphaltene shearing arrays mounted in the conduit. Figure 2 is a plan view of a "right-bend" element used in the apparatus of Figure 1. Figure 3 is a plan view of a "left-bend" element used in the apparatus of Figure 1. Figure 4 is a side view of a typical "right-bend" shear-edge-bearing element useful with the invention. Figure 5 is analagous to Figure 4 but shows a "left-bend" element. Referring to Figure 1, it will be seen that petroleum entering the conduit 11 will meet an ini¬ _4_ tial array 12 of right-bend elements 14 and generally directed in a helical clockwise path into the con- 5 duit. The spacing of elements in zone 12 is achieved by having the appropriate face out and rotating the shaft 15, 90 degrees counterclockwise as each element is dropped onto the shaft from the right end of 10 Figure 1. It will be clear that the polygonal central shaft and element bores provides means to position the elements with precision relative to one another. The lateral edges 16 and side edges 18 of the 15 blades 20 tend to tear at the oil as it rushes past, acting to tear at the oil as it rushes past, acting to -tear apart minute asphaltene particles, or globu¬ les, which are carried in the oil. In practice about a dozen elements of about an inch in diameter are 20 utilized to form this so-called "right bend" pro¬ cessing section. The side designated as "21" in Figure 4 is facing left in Figure 1. There is then space 22 in which there are no elements on central shaft 15. Thereupon, the oil 25 encounters a processing section 24 which is similar to initial array 12 excepting that it is formed of "left-bend" elements 26 and, consequently forces a counter clockwise helical flow of the oil. The side designated as 25 in Figure 5 is facing left in Figure 30 1. The spacing of elements of section, or zone, 24 is achieved by having the appropriate face out and rotating shaft 50, 90 degrees clockwise as each element is dropped onto the shaft from the right end in Figure 1. Again, there is an open space 30 following pro¬ cessing section 24 before the oil encounters a pro¬ cessing zone 32. This element consists of an array of twenty-two right bend elements 14 as shown in Figures 2 and 4 with face 21 out as is the case with array 12 of the first processing zone; however, in section 24 they have been placed on the shaft differently, i.e. they are placed with the same side up, but with the propellors offset from each other to achieve closer packing. Thus a narrower processing helix is formed on about twice as many propellor blades as can be forced into processing section 34. The helical flow path of the fuel being processed is generally clockwise and into the conduit. The spacing of elements of section 32 is achieved by having the appropriate face out and rotating the shaft 90 degrees clockwise as each element is dropped onto the shaft from the right end in Figure 1. Next is an array of compactly-paced counterclock¬ wise helical processing section 40 which bears the same relationship to section 24 that array 34 bears to array 12. "Left bend" elements 42 are used to form section 32 and the face 25 of Figure 25 is the one facing the oncoming flow. The spacing of elements of section 32 is achieved by having the appropriate face out and rotating the shaft 90 degrees counterclockwise as.each element is dropped onto the shaft from the right .end in Figure 1. The fifth shearing section on the shaft is formed by placing alternating members of Figures 2 and 3 on the shaft alternately with sides 21 and 25 facing to the left in Figure 1. The spacing of elements of sec- tion 50 is achieved by having the appropriate face out and rotating the shaft 90 degrees counterclockwise after each element is dropped onto the shaft from the right end of Figure 1. This array 50, if inspected closely, is also seen to have a generally helical flow path 52. However, the centerline of the helical flow path follows a zig-zag course providing a particularly severe treatment of the oil before it exits from the device. Moreover, the relatively high pressure drop through this array provi- des a mechanism to fine-tune the flow characteristics of a particular liquid by adding and substracting a number of blade-bearing elements from the shaft. Thus, it is seen that fuel oil, and more par¬ ticularly globules of asphaltene therein, are constrained by conduit 11 in such a way that they tend to follow helical flow paths 60 formed by the shearing elements. Imperfect geometry of the blade causes a somewhat irregular offset of the shearing elements causes the asphaltene to be more effectively impacted and cominuted by edges 16 and 18 of the blades. The V- shaped open spaces 62, (with the angle of the "V" being more remote from the interior of the wall than the mouth of the "V") between the blades accentuates this effect. The particular configuration of a given array determines whether the amount of resistance to flow and shearing capability. An array such as array 50 with a zig-zag helical path has particularly high shear capa¬ bilities. In general, it is desirable for the center line of a helical flow path to go through at least revolution per each unit length of an array which unit is equal to the average diameter of conduit 11. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which might be said to fall therebetween.

Claims: WHAT IS CLAIMED IS; 1) Apparatus for cominuting discrete asphaltene entities carried in a fuel oil said apparatus compri- sing: (a) an exterior conduit forming means to constrain the flow of said oil; (b) an array of shearing-elements mounted within said exterior conduit; (c) said shearing elements having shearing edges and being arranged to define an array of generally helical flow ' paths; and (d) wherein adjacent elements form wall sec- tions of said helical paths, said wall sections being imperfectly parallel and having spaced openings therein. 2) Apparatus as defined in Claim 1 wherein said spaced openings are bounded by said shearing edges of said shearing elements. 3) Apparatus as defined in Claim 1 wherein said spaced openings are generally V-shaped, with the angle of said V-shape being more remote from the interior wall of said conduit than the mouth of said "V". 4) Apparatus as defined in Claim 2 wherein said spaced openings are generally V-shaped, with the angle of said V-shape being more remote from the interior wall of said conduit than the mouth of said "V". 5) Apparatus as defined in Claim 1 comprising a plurality of said arrays, separated from one another by a short distance along said conduit. 6) Apparatus as defined in Claim 2 comprising a plurality of said arrays , separated from one another by a short distance along said conduit. 7) Apparatus as defined in Claim 3 comprising a plurality of said arrays, separated from one another by a short distance along said conduit. 8) Apparatus as defined in Claim 4 comprising a plurality of said arrays, separated from one another by a short distance along said conduit. 9) Apparatus as defined in Claim 5 wherein at least two adjacent arrays have oppositely directed helical flow paths. 10) Apparatus as defined in Claim 1 wherein at least one array in which the center-line of said helical flow path zig-zags. 11) Apparatus as defined in Claim 5 wherein at least one array in which the center-line of said heli- cal flow path zig-zags 12) Apparatus as defined in Claim 7 wherein at least one array in which the center-line of said heli- cal flow path zig-zags 13) Apparatus as de ined in Claim 8 wherein at least one array in which the center-line of said heli- cal flow path zig-zags 14) Apparatus as defined in Claim 1 wherein at least one array in which the center line of a helical flow path goes through at least about §_ revolution per each unit length of said array which unit length is equal to the average diameter of said conduit. 15) Apparatus as defined in Claim 5 wherein at least one array in which the center line of a helical flow path goes through at least about \ revolution per each unit length of said array which unit length is equal to the average diameter of said conduit. 16) Apparatus as defined in Claim 7 wherein at least one array in which the center line of a helical flow path goes through at least about \ revolution per each unit length of said array which unit length is equal to the average diameter of said conduit. 17) Apparatus as defined in Claim 8 wherein at least one array in which the center line of a helical flow path goes through at least about \ revolution per each unit length of said array which unit length is equal to the average diameter of said conduit. 18) Apparatus as defined in Claim 9 and containing in addition at least one array in which the center-line of said helical flow path zig-zags. 19) A process for conditioning comprising liquid petroleum comprising a substantial quantity of asphaltene, said processing comprising the steps of: (a) flowing said fuel oil through a conduit comprising an array of shearing elements mounted along the interior of said conduit in such a way as to direct said flowing into a helical path; (b) reversing said flow through a series of differently-oriented helical paths during said flowing through said conduit; (c) maintaining said flow at a velocity across said shearing element sufficient to co inute said asphaltene and disperse it within the oil as a readily-combustible material; and (d) burning said fuel oil. 20) A process for utilizing fuel oil of the type comprising a substantial quantity of asphaltene, while simultaneously avoiding quantities of particulates in said stack gas said process comprising the steps of: (a) flowing said fuel oil through a conduit comprising an array of shearing elements mounted along the interior of said conduit in such a way as to direct said flowing into a helical path; (b) reversing said flow through a series of differently-oriented helical paths during said flowing through said conduit; (c) maintaining said flow at a velocity across said shearing element sufficient to cominute said asphaltene and disperse it within the oil as a readily-combustible material; and (d) burning said fuel oil.

Inventors: PSALTOPOULOS EMMANUEL, PSALTOPOULOS, EMMANUEL
Applicants: COLUMBIA CHASE CORP, COLUMBIA CHASE CORPORATION
Application year: 1986
Main classification: B03B7
IPC codes: B01F7, C10G31, C10L1