EP0291504A1

EP0291504A1 - Method and apparatus for treating asphaltene bearing fuels

Info

Publication number: EP0291504A1
Application number: EP87900417A
Authority: EP
Inventors: Emmanuel Psaltopoulos
Original assignee: HYDRO-ENERGY SYSTEMS Inc (an Isle of Man company); Columbia Chase Corp
Current assignee: HYDRO-ENERGY SYSTEMS INC. (AN ISLE OF MAN COMPANY)
Priority date: 1986-11-28
Filing date: 1986-11-28
Publication date: 1988-11-23
Also published as: JPH01501452A; WO1988003836A1; EP0291504A4

Abstract

Les appareils connus de traitement de combustible contenant de l'asphaltène présentent des avantages de ne pas pouvoir réduire suffisamment la taille des particules d'asphaltène indésirablement grandes dans des huiles de pétrole lourdes. Le problème sus-mentionné est résolu par l'utilisation d'un appareil comprenant une série de lames de cisaillement serrées les unes par rapport aux autres qui sont en contact avec l'écoulement de liquide. Les lames sont portées par des pièces en forme d'hélices (14, 26) et sont montées sur un arbre axial (15) dans un conduit (11). Des groupes (12, 24, 35, 40 et 50) des pièces portant les lames de cisaillement sont prévues axialement le long de l'arbre. Les pièces de chaque groupe ont une orientation et configuration uniques par rapport aux pièces d'un autre groupe. Du mazout contenant des particules d'asphaltène s'écoule le long de l'arbre (15). Le mazout est mis en contact et conditionné par les lames de cisaillement. Les particules d'asphaltène sont réduites jusqu'à avoir une taille extrêmement petite de manière à être brûlées facilement dans une chaudière et retrouver des matières particulaires de taille réduite dans l'effluent sortant par la cheminée.Known asphaltene fuel treatment devices have the advantages of not being able to sufficiently reduce the size of the undesirably large asphaltene particles in heavy petroleum oils. The above-mentioned problem is solved by the use of an apparatus comprising a series of shear blades clamped relative to one another which are in contact with the flow of liquid. The blades are carried by propeller-shaped parts (14, 26) and are mounted on an axial shaft (15) in a conduit (11). Groups (12, 24, 35, 40 and 50) of the parts carrying the shear blades are provided axially along the shaft. The pieces of each group have a unique orientation and configuration compared to the pieces of another group. Fuel oil containing asphaltene particles flows along the tree (15). The fuel oil is brought into contact and conditioned by the shear blades. The asphaltene particles are reduced to an extremely small size so that they can easily be burned in a boiler and find reduced particulate matter in the effluent leaving the chimney.

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 graduated 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 conduit. 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-bear ing 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 considerably shipment-to-shipment. SUMMARY OF THE INVENTION

It is a principal object of the invention to provide an improved high-intensity apparatus for use in liquid processing.

It is a particular object of the invention to provide an improved process for reducing the size of undesirably large asphaltene particles in heavy fuel oils, thereby rendering the oil more suitable for clean combustion.

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 configuration 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 characteristic 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 substential 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 ffom their initial size -- often 15 to 50 microns-- to below 10 microns in average diameter.

The desired cominuting action can be achieved in a short length of reactor and in a single pass, a major advance over the shear-processing of asphaltene heretofore known to the art. In the most advantageous embodiments 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) initiated 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 cominuting action, are desirably formed of small stamped propellors which, when mounted adjacent to one another on a shaft, leave small gaps between propellors, simulating 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 propellor surfaces are somewhat and irregularly offset from one another along what would otherwise be an 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 elements 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.

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 substantially different characteristics depending upon the source of petroleum and its treatment after withdrawal from its source. Thus, even within a given fuel shipment, 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 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 forms, it has been found that the process described by Batra can be of incremental value in treating asphaltenes when it is used in series with the apparatus newly describe herein. Moreover, the addition of water to the fuel system appears to provide some advantage 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 thereon and will be able to modify it and embody it in a variety of rorms, 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 conduit 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 initial array 12 of right-bend elements 14 and generally directed in a helical clockwise path into the con- 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 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 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 globules, which are carried in the oil. In practice about a dozen elements of about an inch in diameter are utilized to form this so-called "right bend" processing 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 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 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 processing section 24 before the oil encounters a processing 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 counterclockwise 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 section 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 provides 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 particularly 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 capabilities. In general, it is desirable for the center line of a helical flow path to go through at least ½ 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 intenden 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 comprising: (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 sections 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 helical flow path zig-zags

12) Apparatus as defined in Claim 7 wherein at least one array in which the center-line of said helical flow path zig-zags

13 ) Apparatus as defined in Claim 8 wherein at least one array in which the center-line of said helical 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 ½ 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 ½ 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 ½ 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 ½ 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 cominute 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.