Sonication systems and methods for separating materials in fluids

Abstract

A system can include a vessel having a plurality of sonication devices for separating a base hydrocarbon mixture that is disposed in the vessel. The sonication devices can be mounted on opposing walls of the vessel. A mixer can establish a flow of the vessel mixture within the vessel that increases exposure of the mixture to ultrasonic waves emitted by the sonication devices and carried in the water matrix. The flow of the vessel mixture within the vessel also facilitates removal of oil from the vessel mixture.

Description

SONICATION SYSTEMS AND METHODS FOR SEPARATING MATERIALS INFLUIDSRELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63 / 723,399, filed November 21, 2024, which application is incorporated herein by reference.TECHNICAL FIELD

[0002] Embodiments described herein relate generally to separating materials in fluids, semi-solids, and solids, and more explicitly to systems, methods, and devices for using sonication to separate materials in fluids, semi-solids, and / or solids.BACKGROUND

[0003] There are a number of circumstances where fluids, semi-solids, and solids are a mixture of multiple materials, and extraction of one or more of those materials has a useful purpose. A number of applications produce large amounts of these mixtures that continuously accumulate in process equipment. For example, in oil and gas field operations, fluids, semi-solids, and / or solids (with crude oil) that contain sediment (sand, silts, clays, drilling cuttings) are extracted from subterranean formations on a continuous basis via exploratory / well drilling and oil production / refming. Drilling produces “drillcuttings” which are a mix of sediment / formation material which contains oil-based drilling fluids and may also contain water. Oil production generates fluids, semi-solids, and / or solids that settle in / on process equipment, vessels, and conveyances, creating fluids, semisolids, and solids that contain a mix of oil and solids. This latter group is frequently referred to as crude oil sludges. Equipment / vessels include, but are not limited to, primary and process storage / staging tanks, impoundments, oil-water separators, heat exchangers, and pipes. Wastes include, but are not limited to, tank bottoms, impoundment accumulations, pigging wastes, and residues on equipment. Periodic cleaning of equipment / vessels frequently utilizes water in the cleaning process and thus adds one more material to the crude oil sludge. Other mixtures include mixes of surficial sediments andoil from spill cleanups, or oily sediment discharge from centrifuges designed to separate water and oil from oil / water / sediment mixes. During exploration, production, and refining operations, separating the oil from this fluid can be useful for crude oil recovery, drilling fluid recovery, and waste minimization.

[0004] For ease of reference, the foregoing fluids, semi-solids, and solids may be generally referred to herein as a base hydrocarbon mixture.

[0005] U.S. Patent No. 11,414,327 describes the use of sonication or ultrasonics to separate the above-mentioned materials in fluids. However, challenges remain in the use of sonication techniques for separating those materials. For example, drilling additives present in drilling fluids can inhibit the separation of the components in a fluid, semi-solid, or solid mixture, and oil viscosity or API gravity can affect how oil separates from the sedimentary matrix. Therefore, further improvements in sonication techniques that enable greater oil recoveries and cleaner residuals for disposal would be beneficial. Additionally, sonication techniques that require less energy than prior separation techniques would also be of benefit.SUMMARY

[0006] The examples provided herein are directed to sonication systems used for separating base hydrocarbon mixtures. In one embodiment, a system comprises a vessel having first and second end walls, first and second side walls, and a bottom wall defining a cavity for containing the mixture. The system further comprises a first plurality of sonication devices mounted on an exterior surface of the first side wall, wherein the first plurality of sonication devices direct first ultrasonic waves through the first side wall and into the cavity. The system also comprises a second plurality of sonication devices mounted on an exterior surface of the second side wall, wherein the second plurality of sonication devices direct second ultrasonic waves through the second side wall and into the cavity. The system includes an added water feed for providing added water to the vessel, a mixer(s) for combining the added water and the base hydrocarbon mixture to create a vessel mixture. An oil removing system removes from the vessel oil that has separated from the vessel mixture due to the effects of heat and ultrasonic waves. At leastone drainage port located at one of the end walls or side walls can be used to remove at least a portion of the vessel mixture from the vessel.

[0007] Another embodiment provides a method for separating sediment and oil from a base hydrocarbon mixture. The method includes introducing the base hydrocarbon mixture into a vessel having first and second end walls, first and second side walls, and a bottom wall defining a cavity for containing the base hydrocarbon mixture, although the cavity could be other shapes such cylindrical or polygonal. The method further includes mixing the base hydrocarbon mixture and added water with a mixer disposed in the vessel to create a vessel mixture. The vessel mixture is treated with ultrasonic waves that are applied by a first plurality of sonication devices mounted to an exterior surface of the first side wall and a second plurality of sonication devices mounted to an exterior surface of the second side wall and heaters (conductive, steam, or other) as necessary to drive the vessel mixture to a desired treatment temperature. The method further includes collecting the oil that has separated from the vessel mixture at the top surface of the vessel mixture. After treatment with the ultrasonic waves, the mixing ceases allowing sediment to collect along the bottom wall of the vessel facilitating draining of remaining vessel mixture from the vessel and removal of the sediment from the bottom wall.

[0008] These and other aspects, objects, features, and embodiments will be apparent from the following description and the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings illustrate only example embodiments of sonication equipment, methods, and / or techniques for separating materials in fluids and are therefore not to be considered as limiting the scope of the disclosure. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or positions may be exaggerated to help visually convey such principles. Inthe drawings, reference numerals designate like or corresponding, but not necessarily identical, elements.

[0010] Figure 1 shows a diagram providing a perspective view of a system for separating materials in a base hydrocarbon mixture in accordance with certain example embodiments.

[0011] Figure 2 shows a schematic illustration of a top view of the system of Figure 1 in accordance with certain example embodiments.

[0012] Figure 3 shows a schematic illustration of a side view of the system of Figure 1 in accordance with certain example embodiments.

[0013] Figure 4 shows an illustration providing a perspective view of a system for separating materials in a base hydrocarbon mixture in accordance with another example embodiment.

[0014] Figure 5 shows an illustration providing a top view of the system of Figure 4 in accordance with certain example embodiments.

[0015] Figure 6 shows an illustration providing a side view of the system of Figure 4 in accordance with certain example embodiments.

[0016] Figure 7 shows an illustration providing a perspective view of a system for separating materials in a base hydrocarbon mixture in accordance with yet another example embodiment.

[0017] Figure 8 shows an illustration providing a perspective view of a system for separating a base hydrocarbon mixture in accordance with yet another example embodiment.

[0018] Figure 9 is a flow chart illustrating a process for separating materials in a base hydrocarbon mixture in accordance with certain example embodiments.DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0019] The example embodiments discussed herein are directed to systems, methods, and devices using sonication to separate materials in base hydrocarbon mixtures. While example embodiments are described herein as being used with fluids containing hydrocarbons (e.g., crude oil) during exploration and / or production of a subterranean field (e g., oilfield), example embodiments can also be used with fluids containing any of anumber of other materials (e.g., gold, iron) that are used in any of a number of other applications (e.g., water extraction, formation fracturing, mining). Example embodiments can be used in any type of environment (e.g., indoor, outdoor, hazardous, non-hazardous, high humidity, low temperature, corrosive, sterile, high vibration).

[0020] As will be described in further detail below in connection with the example embodiments, the systems, methods, and devices disclosed herein improve upon existing approaches to using sonication for the separation of materials from fluid, semi-solid, or solid mixtures. The equipment, methods, and techniques described herein improve the efficiency and performance of sonication systems.

[0021] Example embodiments of sonication for separation of materials in base hydrocarbon mixtures will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of sonication systems are shown. Sonication systems may, however, be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of sonication for separation of materials in base hydrocarbon mixtures to those of ordinary skill in the art. Like, but not necessarily the same, elements (also sometimes called components) in the various figures are denoted by like reference numerals for consistency.

[0022] Referring now to the drawings, in a first example embodiment of the disclosure, Figures 1-3 illustrate a sonication system 100 that uses sonication to separate materials in base hydrocarbon mixtures. Another example embodiment of a sonication system 200 is illustrated in Figures 4-6. Yet additional example embodiments of sonication systems 300 and 400 are illustrated in Figures 7 and 8, respectively. The sonication systems of Figures 1-8 are non-limiting examples and other arrangements of the mixers, the oil removing systems, the inlet and outlet ports, and / or the sonication devices are within the scope of this disclosure. Moreover, components from one example embodiment can be applied to a different example embodiment. Lastly, Figure 9 is a flow chart illustratingan example process for separating materials in fluids, semi-solids, and / or solids using a sonication system.

[0023] Any of the sonication systems described herein can be used to separate hydrocarbons (e.g., oil) from a base hydrocarbon mixture. When the mixture is an oily sludge (also sometimes called petroleum or oil-impacted sludges), the oily sludge is frequently generated as waste streams of oil and gas production and refining operations and requires proper treatment and disposal. Oily sludges can be generated from solids, sand, and / or sediment accumulating in, but not limited to, primary and process storage / staging tanks, impoundments, oil-water separators, heat exchangers, and pipes. Wastes include, but are not limited to, tank bottoms, impoundment accumulations, pigging wastes, and residues on equipment. Oily sludges and solids can also be generated because of unintentional oil product release that can impact soil and sediments in the environment. Periodic cleaning of equipment / vessels frequently utilizes water in the cleaning process and thus adds one more material to the sludge or mixture.

[0024] The composition of the base hydrocarbon mixture in the form of oily sludge can include, but is not limited to, petroleum hydrocarbon (PH), sediment, water, metals, solid particles, and / or co-contaminants. The types and concentrations of PHs in oily sludge can vary widely and are often tested using chemical analysis to help determine how best to manage the oily sludge. Petroleum hydrocarbon type and concentration can influence oil recovery potential, waste treatability performance, and waste minimization potential of oily sludges. At times, oily sludge with unrecovered oil is disposed of in industrial waste landfills or hazardous waste incinerators.

[0025] Another example of a base hydrocarbon mixture that can be targeted in a separation process is oil-based mud (OBM) that is contaminated with drill cuttings. Drill cuttings are generated during oil and gas exploration and drilling operations, when subsurface material (e.g., soil, sand, rock) is cut by a drill bit and subsequently carried to the surface by either water-based drilling fluid (WBF) or non-aqueous (organic) drilling fluid (NAF). NAF, which is an expensive fluid that can be reused if recoverable, can be formulated with diesel, mineral oil, and / or low-toxicity linear olefins, paraffins, and esters. The NAF content remaining in drill cuttings waste is typically defined as retention oncuttings (ROC), which represents a financial loss since new fluids must be purchased to replace fluids that are lost and disposed of as waste.

[0026] Referring again to Figures 1-3, the sonication system 100 comprises a vessel 104 that contains the base hydrocarbon mixture. Example vessel 104 has a generally cuboid shape, but in other embodiments the vessel can have other shapes, including but not limited to cylindrical or polygonal. The walls of vessel 104 are preferably made of stainless steel, which has been found to be more effective than other materials at reflecting ultrasonic waves. Stainless steel also offers superior resistance to degradation from the ultrasonics and corrosion. However, in other embodiments, the vessel walls may be in or above the ground surface and comprise materials, such as steel, aluminum, cement, or plastic. Vessel 104 comprises a first end wall 106, a first side wall 108, a second end wall 110, a second side wall 112, and a bottom wall 107. Optionally, the vessel 104 may have a top wall. When the vessel has other shapes such as cylindrical or polygonal, the terms “first side wall” and “second side wall” can be used to refer to portions of the vessel that are generally opposite each other.

[0027] Walls 106, 108, 110, and 112 of the vessel 104 are shown in Figures 1-3 as meeting at and forming sharp comers with the bottom wall 107. However, it has been found that forming rounded corners between walls 106, 108, 110, and 112 with the bottom wall 107 within the vessel 104 improves the mixing and flow of the fluidized contents within the vessel 104.

[0028] At an end wall 106, a mixture inlet 116 feeds a base hydrocarbon mixture into the vessel 104. However, inlet 116 could be on either of the end walls 106 or 110 or in any suitable location on the vessel as needs would dictate. Also, fluid or semi-solid base hydrocarbon mixtures could be added via hose or piping over the upper rim of the vessel and directly into the vessel. For semi-solid or solid base hydrocarbon mixtures, they could be added via front-end loader or similar method over the rim of the vessel. Additionally, a water inlet 118 at end wall 106 feeds water (referred to herein as added water) to the vessel 104, however, added water could also be fed from end wall 110 or any location over the upper rim of the vessel via hose, piping, or similar equipment. Optionally, the added water may be heated before it is fed to the vessel 104. Because heating is a critical part of the treatment process described herein, adding heated water can accelerate the treatmentprocess, facilitating separation of materials from the mixture. The combination of the base hydrocarbon mixture and the added water in the vessel is referred to as a vessel mixture.

[0029] In the example system 100 of Figures 1-3, a mixer 130 located proximate to the end wall 106 mixes the added water and the base hydrocarbon mixture, thereby homogenizing and suspending the solids from the base hydrocarbon mixture in the resulting vessel mixture. The mixer 130 is designed to agitate and lift the base hydrocarbon mixture so it is in suspension in the added water to enable more effective sonication treatment and to ensure oil or contaminants do not get trapped in a mass of static solids / sludges. This mixer action can be affected in numerous ways including propeller mixers, fluid jets, eductor jets, air bubbling, inductor jets, and propeller driven draft tubes. In one embodiment, if the vessel is deep enough, one or more mixer(s) 130 could be positioned toward the bottom of an end wall 106 or 110 so that, in addition to causing suspension of the base hydrocarbon mixture, a circular flow is established within the vessel. The circular flow of the fluid mixture, comprising the fluid / semi-solid / solid mixture and the added water, is illustrated in Figure 3. The circular flow of the vessel mixture, comprising the base hydrocarbon mixture and the added water, driven by horizontally mounted mixer(s) 130 on first end wall 106, first flows along the bottom wall 107 from the first end wall 106 toward the second end wall 110. Upon encountering the second end wall 110, the circular flow of the vessel mixture travels upward and then back along the surface toward the first end wall 106. The circular flow of the vessel mixture keeps the mixture in suspension, ensures even heating of the vessel mixture, and facilitates exposing the oil / sediment in the base hydrocarbon mixture to ultrasonic waves emitted by the banks of sonication devices. In addition, the surface flow which travels back toward the first end wall 106 consolidates oil that has been released by the sonication process allowing the released oil to be collected.

[0030] Other embodiments for propeller mixers include mixers positioned vertically along the midline or along the side walls 108, 112 of the vessel for mixing, similar to the example described below in connection with Figure 7. In another alternative, mixing can be accomplished with one or more draft tubes located along the side walls 108, 112 or end walls 106, 110. With an intake toward the top of the vessel mixture level within the vessel 104 and an outlet in-line with the bottom wall 107 of the vessel, the draft tubes have propeller mixers located within the vertical aspect of the draft tube and oriented suchthat it drives the vessel mixture vertically downward through the draft tube and out the base of the draft tube along the bottom wall 107. The draft tube collects the fluid mixture toward the top of the vessel mixture surface along the side walls 108, 112 or end walls 106, 110 and ejects the fluid mixture horizontally at the base of the same side walls 108, 112 or end walls 106, 110, thereby agitating and lifting the mixture on the bottom of the vessel, causing it to mix with the vessel mixture above it in the vessel 104. In other embodiments, mixing can be accomplished with eductor jets or inductor jets, which would be placed appropriately at the base of side walls 108 and / or 112 and / or at the base of end walls 106 and / or 110 as needed with the jets oriented along the bottom wall 107 and would use the vessel mixture to mix and suspend the base hydrocarbon mixture . In yet another embodiment, mixing can be accomplished with air bubblers, which would be placed along bottom wall 107 to create a lifting action, thus mixing the base hydrocarbon mixture and keeping it in suspension in the added water.

[0031] As shown in Figures 1 and 2, a bank of sonication devices (or simply sonicators) 135 is located along both the first side wall 108 and the second side wall 112. Sonication devices can also be applied to any surface including the bottom as need dictates. Sonication devices generate ultrasonic waves by magnetostrictive or piezoelectric methods. With magnetostrictive generation, alternating current (AC) electrical energy is converted to mechanical vibration energy via a magnetic coil which, when energized, deforms the shape of a magnetized element (typically nickel or iron). Rapid energizing / de- energizing of the magnetic coil in response to the wave-frequency of the AC current forces rapid vibration of the element, which produces the ultrasonic vibration. Due to the nature of materials used, the vibration frequency of magnetostrictive sonication devices is limited to certain frequencies based on their construction, but a common frequency is 30 kHz. Due to its construction and since it must be brazed to the vessel wall, the magnetostrictive sonication device almost never experiences a failure.

[0032] With piezoelectric sonication devices, AC current that is tuned to the natural frequency of one or more piezoelectric crystals is used to generate the ultrasonic waves. AC current in tune with a piezoelectric crystal forces the crystal to expand and contract at the wave-frequency of the AC current, thereby producing the ultrasonic waves. A benefit to piezoelectric sonication devices is that they can be designed for a wide variety ofultrasonic vibrational frequencies and / or can provide user adjustable frequencies. Piezoelectric sonication devices are glued or epoxied to the vessel surface. Drawbacks with the piezoelectric sonication devices is that the ultrasonic signal fades as the crystal degrades, and the glue or epoxy bonds can fail.

[0033] It has been found that magnetostrictive sonication devices work particularly well for the example embodiments described herein because their ultrasonic vibrational frequency falls within a zone useful for treatment of crude oil sludges. Additionally, magnetostrictive sonication devices are far more robust and rarely experience a failure or detachment from the vessel wall. However, given its variable frequency attributes, the piezoelectric transducer cannot be ruled out for use.

[0034] The use of ultrasound (e.g., waves having a frequency of 20 kHz to 200 kHz) or sonication has been shown to assist in the desorption of materials from solid particles, separation of mixtures of solids and liquids, and destabilization of water and oil emulsions. Also known as cavitation phenomena, sonication generates compressions and rarefactions in a multi -material fluid as it impacts a solid particle (i.e., soil particles or sediment). A compression cycle gives positive pressure on the fluid by pushing molecules together while a rarefaction cycle provides a negative pressure by pulling molecules in the fluid apart. It is during the rarefaction cycle that the cleaning or removal of crude oil takes place.

[0035] Water is an effective propagation medium for sonic waves and is the medium of choice for applications discussed herein. Because ultrasonic waves typically attenuate rapidly in a fluid mixture within the vessel, the “throw” or transmission distance in clean water is approximately 36 inches. As such, it has been found that positioning a bank of sonication devices on each of the first side wall 108 and the second side wall 112, wherein the opposing side walls are spaced apart no more than 72 inches, preferably less, improves the performance of the sonication system 100. For example, the distance between the opposing side walls and their respective banks of sonication devices is preferably in the range of 50 to 72 inches. The emitting surface of each sonication device is facing toward the center of the vessel 104 and toward the opposite wall. With each bank of sonication devices emitting ultrasonic waves toward the center of the vessel 104 and toward theopposite wall, it increases the exposure of the vessel mixture to the ultrasonic waves, thereby enhancing separation of the materials in the vessel mixture.

[0036] A further attribute of the sonication system 100 is that the sonication devices 135 are mounted along the exterior surface of the first side wall 108 and the second side wall 112. When mounted on the exterior surfaces of the side walls, the ultrasonic wave vibration from the sonication devices 135 cause the tank wall to which they are attached to vibrate, which induces the ultrasonic waves in the interior of the vessel 104 where they facilitate detachment of oil from the underlying solid particulate in the vessel mixture. Mounting the sonication devices on the exterior surfaces of the first side wall 108 and the second side wall 112 allows the interior surfaces of the first side wall 108 and the second side wall 112 to remain smooth and free of obstructions. In other words, if the sonication devices were mounted on the interior surfaces of the side walls, there would be obstructions that would interfere with the smooth flow of the vessel mixture in the vessel 104. It has been found that maintaining the interior surfaces of the walls of the vessel smooth and free of obstructions maintains a robust circulation of the vessel mixture in contact with the side walls, thereby minimizing the effects of attenuation of the ultrasonic waves, increasing exposure of the vessel mixture to the ultrasonic waves, and significantly improving the separation of materials from the vessel mixture.

[0037] The sonication system 100 is operated by ultrasonic generators and controllers housed in a separate cabinet or enclosure (not visible in Figures 1-3 but shown in Figures 4, 7, and 8). The generators provide the ultrasonic signal for the sonication devices 135 on the vessel. Other components such as the mixer(s) 130, heaters, oil skimmers, or other accessories would have their own controllers which may be separate from or included in the generator cabinet. The controllers can include one or more of a number of components including, but are not limited to, voltage specific power supplies, hardware processor(s), controllers, variable frequency drives (VFDs), memory, communication module(s), and transceiver s). If controllers are included in the generator cabinet, it is advantageous to have the on / off switches for analog control or control panels for digital control of controllers mounted on the front panel of the cabinet to negate having to open the generator cabinet. Power supplies or power feeds provide power to various components and controllers including submersible heaters, oil skimmer(s), and any othertank accessories. VFDs control power and control signals to various motor driven components of the sonication system 100 such as the mixer(s) 130 or other tank accessories to control rotational speed. The hardware processor can execute commands stored in the memory that are used to control the operations of the sonication system 100. The communication module and transceiver can enable the controller to communicate with components of the sonication system 100, including one or more sensors such as a passive infrared sensor, a photocell, a pressure sensor, an air flow monitor, a fluid level detector, a vibration sensor, a gas detector, a voltmeter, an ammeter, a camera, and / or a resistance temperature detector. The communication module and transceiver also can enable the controller to communicate with components of other systems external to the sonication system 100. In addition to operating the sonication system 100, the controller can communicate with and / or control additional sonication systems.

[0038] Another accessory that could be added to the vessel are load cells (weighing devices) that the tank sits on. At least four load cells for a rectangular tank (or an appropriate number based on tank shape) and a display would be required. Readings from the load cells would allow the user to monitor tank weight before, during, and after each sonication treatment to facilitate understanding of the mass of the base hydrocarbon mixture and the added water in each treatment and the masse of each post-treatment phase including free oil and sediment.

[0039] In addition to basic control systems, warning systems could include low fluid level indicators / warnings, heater fluid-level, and / or failure indicators / warnings. To assist in fluid level control, a float-valve fill system could be incorporated to ensure the water level within the vessel is always maintained. Vessel temperature sensors and temperature controllers could also be used to monitor temperatures of the vessel mixture, achieve and maintain a set treatment temperature.

[0040] As the ultrasonic treatment process separates the oil and other components of the vessel mixture circulating in the vessel 104, the oil collects along the top surface of the vessel mixture. Based on the method of mixing the vessel contents, a variety of methods could be used to collect this free oil. If vertical mixers are used, free oil could be collected using a variety of oil removing systems, including rope skimmers, tube skimmers, belt skimmers, drum skimmers, disc skimmers, fixed weir skimmers, or floating weirskimmers. Tn contrast, the other materials of the base hydrocarbon mixture other than the separated oil continue to reside in the vessel mixture circulating in the vessel. Placement of these oil removal / skimming devices would depend on the attributes of the skimmer device chosen and may require recirculation or replacement of collected water drawn off by the skimmer device. In addition, as oil is lost due to collection, that volume must also be replaced by water to maintain the level of the vessel mixture within the vessel. It is also possible that additional base hydrocarbon mixture or added water could be added during the sonication treatment to offset the oil that is separated and removed.

[0041] If mixers that create directional flow at the surface such as that shown in Figure 3 are used, oil removing systems such as belt skimmers, drum skimmers, disc skimmers, fixed weir skimmers, or floating weir skimmers could be used to collect the oil released from the vessel mixture. The directional flow of the surface fluids of the vessel mixture can provide added benefit for oil removal. Based on the example shown in Figure 3, as the vessel mixture flows along the top of the vessel 104 toward the first end wall 106, the vessel mixture encounters a separation device 140 (a type of oil removing system), such as a weir. The separation device 140 allows the separated oil on the top surface of the vessel mixture to flow toward the skimmers 142 and 143, which direct the separated oil to the oil outlet 145 and the oil container 148. The water that flowed along the top of the vessel contents but was obstructed by the separation device 140 and not collected by the skimmer device, will flow downward upon encountering the separation device 140 and return to the circular flow of the base hydrocarbon mixture in the added water in the vessel 104 where they will be exposed to further ultrasonic waves.

[0042] If the base hydrocarbon mixture includes hydrocarbons containing potentially flammable or explosive compounds that may be volatilized during heating, the sonication system and any associated component can be constructed to meet hazardous environment electrical codes. To ensure safety, the sonication system could be outfitted with equipment to minimize accumulation of hazardous gases. As one example, fans or blowers may be installed on or around the sonication system. As another example, a purge and pressurize system could be used to purge and pressurize the sealed electrical components to minimize the intrusion of flammable gases that could cause a fire or explosion.

[0043] When the successful ultrasonic treatment of the vessel mixture in the vessel 104 is complete, the vessel contents will be stratified into fluid, semi-solid, or solid layers with predominantly oil at the top surface of the vessel contents, predominantly water in the middle layer which transitions to a mix of oil, water, and residual sediment toward the base of that middle layer, and predominantly heavier sediment in the bottom layer. One or more of the fluid layers of the vessel mixture can be drained from the vessel 104 through the drainage ports 120.

[0044] Referring now to Figures 4-6, a second example embodiment of a sonication system 200 is illustrated. Sonication system 200 is similar in several respects to sonication system 100 of Figures 1-3. Sonication system 200 includes a vessel 204. Vessel 204 comprises a first end wall 206, a first side wall 208, a second end wall 210, a second side wall 212, and a bottom wall 207. Optionally, the vessel 204 may have a top wall.

[0045] At an end wall 206 or 210, a mixture inlet 216 feeds the base hydrocarbon mixture into the vessel 204. Alternatively, the base hydrocarbon mixture could be fed over the top walls of the vessel via a hose or piping, or in the case of semi-solid or solid base hydrocarbon mixtures, they could be added by a method such as front-end loader or similar device over the top edge of the vessel. Additionally, a water inlet 218 feeds added water to the vessel 204 or added water could be added by hose over the top rim of the vessel 204. Optionally, the added water may be heated before it is fed to the vessel 204, since heated water facilitates mixing and separation of materials in the vessel mixture formed by the combination of the base hydrocarbon mixture and the added water.

[0046] For sonication system 200 as shown in Figures 4-6, mixers would be vertical and located down the centerline of the vessel. Vertical mixers would be attached via additional attachments to the vessel such as brackets. They would not be inserted through the wall of the vessel as shown in Figures 1-3, sonication system 100. The example of Figure 7, which is described below, shows a vertical mixer.

[0047] As with the sonication system 100, sonication system 200 includes banks of sonication devices (or simply sonicators) 235 located along the first side wall 208 and the second side wall 212 or could be applied to any wall including the bottom. Sonication devices generate ultrasonic waves that are directed into the vessel 204 and act to separate the materials of the vessel mixture therein. Similar to the previous description, thesonication devices 235 are attached to the exterior surfaces of the first side wall 208 and the second side wall 212. Attaching the sonication devices 235 to the exterior surfaces of the first side wall 208 and the second side wall 212 leaves the interior surfaces of the side walls smooth and free of obstructions to promote the flow of the vessel mixture and robust contact between the vessel mixture and the interior surfaces of the side walls. A robust flow of the vessel mixture and robust contact with the side walls minimizes the effects of attenuation of the ultrasonic waves, increases exposure of the vessel mixture to the ultrasonic waves, and significantly improves the separation of materials from the fluid flow, the magnetostrictive sonication devices 235 are brazed to the side walls 208 and 212 and the side walls are made of stainless steel to more effectively reflect the ultrasonic waves within the vessel 204.

[0048] Figures 5 and 6 illustrate the junction box 237 of the sonication system 200. While shown with system 200, this would also be an integral part of system 100. Each system 100, 200 also has a separate electronics / generator cabinet 250 (shown in Figure 4) to house the ultrasonic generators and controls for the sonication devices. For example, an ultrasonic generator can be provided for each 500 watts of sonication power (or as designed by the manufacturer). The ultrasonic generators convert AC power to power signals that can be used by the sonication devices. The electronics / generator cabinet 250 is a separate protected environment such as a trailer that includes an incoming power panel. Cooling systems can be incorporated into the trailer and / or the electronics / generator cabinet 250 to ensure the ultrasonic generators do not overheat. The electronics / generator cabinet 250 also includes on / off controls for each generator. Controls and power supplies for additional items, such as mixers, heaters, fans / blowers, and skimmers, also can be housed or routed through the electronics / generator cabinet 250 and controls for those items would advantageously be mounted on the door of the cabinet 250. Wiring from the electronics / generator cabinet 250 can be routed to the junction box 237 for distribution to each component.

[0049] While not shown in the example of Figures 4-6, mixers and submersible heaters could be mounted along the length of the vessel 204 parallel to the walls 208 and 212. Ideally, the mount for those components would be on slides that would allow the mixers and heaters to be moved from the center of the vessel 204 to the side and back asneeded for loading the vessel 204. Another alternative for heating could be the use of steam.

[0050] An oil removing system or separation device is not illustrated in the sonication system 200 of Figures 4-6. However, any of a variety of oil removing systems or separation devices as described for system 100 could be used with the system 200, including a skimmer, a weir, or an oil boom.

[0051] When the successful ultrasonic treatment of the vessel mixture in the vessel 204 is complete, the vessel contents will be stratified into fluid, semi-solid, or solid layers with predominantly oil at the top surface of the vessel contents, predominantly water in the middle layer which transitions to a mix of oil, water, and residual sediment toward the base of that middle layer, and predominantly heavier sediment in the bottom layer. One or more of the fluid layers of the vessel mixture can be drained from the vessel 204 through one or more drainage ports 220. Vessel 204 is advantageous in that it includes a plurality of vertically staged drainage ports 220. By staging the drainage ports at varying vertical heights on the outlet end wall 210, each layer of the vessel mixture may be drained from a different drainage port 220, thereby maintaining separation of the stratified layers. Similar staged drainage ports also could be used in system 100 of Figures 1-3.

[0052] Referring now to Figure 7, a variation on the embodiment illustrated in Figures 4-6 is provided. The previous descriptions of components shown in Figures 4-6 apply to analogous components of Figure 7 and, therefore, will not be repeated. Similar to system 200, Figure 7 shows a sonication system 300 comprising a vessel 304 having first end wall 306, second end wall 310, first side wall 308, and second side wall 312. The vessel 304 has a mixture inlet 316 for feeding a base hydrocarbon mixture into the vessel 304. The vessel 304 also has a water inlet 318 for feeding added water to the vessel 304. As described previously, a base hydrocarbon mixture and added water also can be introduced into the vessel 304 over a side or end wall. As described previously, a base hydrocarbon mixture combined with added water in the vessel 304 forms a vessel mixture that is acted upon by the sonication system 300.

[0053] The sonication system 300 differs in one respect from the previous examples in that a vertically oriented mixer 330 is mounted at the top of the vessel 304. Additional vertically oriented mixers also could be located at other positions along thelength of the vessel 304. The vertically oriented mixer 330 can include a propeller or other mechanical means for mixing the fluid mixture.

[0054] Another unique feature of the sonication system 300 is that includes a plurality of heaters 338 positioned along the second side wall 312. The heaters 338 heat the fluid mixture to facilitate freeing of oil from the mixture.

[0055] The sonication system 300 also includes a bank of sonication devices 335 located on the exterior of the first side wall 308 and a bank of sonication devices 335 located on the exterior of the second side wall 312. The opposing banks of sonication devices 335 are oriented to direct ultrasonic waves towards the center of the vessel 304 where they act on the vessel mixture to free oil for separation. The sonication devices 335 are powered and controlled by the ultrasonic generators and electronics in the electronics / generator cabinet 350.

[0056] Lastly, the sonication system 300 includes vertically staged drainage ports 320 for draining the various phases of the vessel mixture that have been separated by the sonication devices.

[0057] Referring now to Figure 8, a variation on the embodiments illustrated in Figures 4-6 and 7 is provided. The previous descriptions of components shown in Figures 4-6 and 7 apply to analogous components of Figure 8 and, therefore, will not be repeated. Similar to systems 200 and 300, Figure 8 shows a sonication system 400 comprising a vessel 404 having first end wall 406, second end wall 410, first side wall 408, a second side wall 412, and a bottom wall 407. The vessel 404 has a mixture inlet 416 for feeding a base hydrocarbon mixture into the vessel 404. The vessel 404 also has a water inlet 418 for feeding added water to the vessel 404. As described previously, a base hydrocarbon mixture and added water also can be introduced into the vessel 404 over a side or end wall. As described previously, a base hydrocarbon mixture combined with added water in the vessel 404 forms a vessel mixture that is acted upon by the sonication system 400.

[0058] Similar to previous embodiments described herein, the sonication system 400 includes an oil separator 442, which can be one or more of a skimmer or a weir. The sonication system 400 also includes fans 455 used to disperse fumes that may emanate from the system.

[0059] The sonication system 400 differs in one respect from the previous examples in that vertically oriented mixers 430 and vertically oriented heaters 438 are mounted on a sliding platform at the top of the vessel 404. The platform is advantageous because it allows the mixers 430 and heaters 438 to slide together to the center of the vessel 404 when sonication treatment is being performed. When the vessel is being loaded, emptied, or other maintenance is being performed, the platform with the mixers 430 and heaters 438 can slide to the side to provide greater access to the interior of the vessel 404.

[0060] The sonication system 400 also includes a bank of sonication devices 435 located on the exterior of the first side wall 408 and a bank of sonication devices 435 located on the exterior of the second side wall 412. The opposing banks of sonication devices 435 are oriented to direct ultrasonic waves towards the center of the vessel 404 where they act on the vessel mixture to free oil for separation. The sonication devices 435 are powered and controlled by the ultrasonic generators and electronics in the electronics / generator cabinet 450.

[0061] Lastly, the sonication system 400 includes vertically staged drainage ports 420 for draining the various phases of the vessel mixture that have been separated by the sonication devices.

[0062] Referring now to Figure 9, an example process 900 is illustrated. Process 900 describes a method of using a sonication system to separate the materials in a hydrocarbon base mixture. It should be understood that the operations of process 900 are a non-limiting example, and in other embodiments certain operations of process 900 may be combined, omitted, or performed in a different sequence and other operations may be added to process 900.

[0063] In operation 902, the base hydrocarbon mixture is placed in the vessel of the sonication system and in operation 904 added water is placed in the vessel. As described previously, the base hydrocarbon mixture is combined with the added water in the vessel to form a vessel mixture. As an example, the ratio of the added water to base hydrocarbon mixture in the vessel may be from 1 :1 to 10: 1 (weight / weight). Water enhances the transmission of ultrasonic waves within the vessel, and it provides an effective medium in which materials are suspended to be treated for more effective exposure to the ultrasonic waves.

[0064] In operation 905, heaters, oil skimmers, mixing devices, and fans / blowers of the sonication system can be powered on. As part of the overall treatment, heating of the vessel contents is preferred. During heating, oil will begin to release. For example, oil may begin to release at approximately 45°C, and may continue through 65°C, whereas other products will continue to release oil through 95°C. In addition, heating to 75°C and above encourages a cleaner post-treatment sediment residual. Preferably, the vessel mixture within the vessel is heated to a range of 65°C to 95°C and more preferably a range of 75°C to 90°C to promote the separation of oil from the base hydrocarbon mixture. Alone, the ultrasonic energy during treatment imparts heat to the fvessel mixture. However, supplemental heating is necessary in larger vessel applications. This supplemental heating could be accomplished, in part, by adding heated water during water addition, and / or via resistive / conductive submersible heating elements within the vessel, steam, or a combination of the two.

[0065] In operation 910, a mixer begins mixing the base hydrocarbon mixture and the added water that have been introduced into the vessel. Preferably, pre-treatment mixing is performed for approximately 30 minutes or as deemed necessary which may or may not include sonication in order to agitate the base hydrocarbon mixture on the bottom of the vessel, incorporate the added water, and get the base hydrocarbon mixture to suspend within the added water matrix. When suspended in the water matrix, a robust flow of the vessel mixture as described previously in connection with Figures 2 and 3 allows the mixture to be more readily separated by the ultrasonics, whereas without it the sludge will sit on the bottom of the vessel and will not receive treatment. In some embodiments, additives such as flocculants, coagulants, salt addition, use of reverse osmosis (RO) water as the added-water, and / or pH adjustment may prove a benefit to sediment removal.

[0066] In operation 915, the ultrasonic generators are powered on if not previously done so the with pre-treatment mixing, activating the sonication devices attached to the exterior surfaces of the vessel. Heaters are also turned on to bring the fluid mixture to desired temperature. As the sonication devices emit ultrasonic waves into the vessel, the ultrasonic waves cause oil and other materials to separate from the vessel mixture. While treating the vessel mixture with the ultrasonic waves, the mixer continues to operate tomaintain a robust flow of the vessel mixture and to enhance interaction of the vessel mixture with the ultrasonic waves.

[0067] In operation 920, as oil separates and collects at the top surface of the vessel mixture, the oil is continuously collected using one or more oil removing or separating devices. The collected oil is removed from the vessel and stored for future use. It has been found that continuous collection of oil during the ultrasonic treatment prevents the oil from re-mixing with or sinking in the vessel mixture if / when the vessel mixture cools, therefore, maximizing the amount of oil collected.

[0068] In operation 925, ultrasonic treatment is typically considered complete when a defined treatment temperature, such as 90 °C, has been reached. Using a criteria of “when oil production has stopped” is not an effective criteria for terminating a treatment unless there is previous experience with a vessel mixture that has indicated that no more oil will be produced when such occurs. When treatment is complete, the heaters, mixers and the ultrasonic generators powering the sonication devices are turned off so that the flow gradually stops.

[0069] In operation 930, after the ultrasonic treatment is complete, vessel contents should be allowed to settle for a defined period (e.g., 30-60 minutes) to allow heavy sediment to settle and allow any remaining separated oil to surface and be collected. If desired, the ultrasonic generators can be left on during the settling period to enhance sediment separation. This period should be extended as necessary to allow the oil separating device to collect all free oil on the water surface.

[0070] In operation 935, the stratified phases remaining in the vessel mixture may be drained from the vessel through vertically staged ports. The water and mixed phases that are drained from the vessel may be subjected to other treatment processes.

[0071] Lastly, in operation 940, the sediment remaining at the bottom of the vessel is removed. Sediment removal could embody various options depending on the oil and / or water content of the sediment. Sediment removal could be facilitated by washing the sediment out of the vessel through a discharge port using water jets / spray or could be removed via a dragline or other mechanical excavation method.

[0072] As illustrated by the foregoing example embodiments, one or more sonication systems are used to separate one or more materials (e.g., oil, sand, cuttings,water) from a multi -material fluid, semi-solid, or solid mixture. The example sonication systems described herein are useful for separating the constituents of oily sludge and oilbased mud (OBM) contaminated drill cuttings that are generated, stored, or transferred in connection with oil field operations. Example embodiments can be used to reduce energy demand compared to conventional separation equipment. Example embodiments can be used to recover oil from fluids, semi-solids, or solids (e.g., oily sludge, OBM-contaminated drill cuttings). Example embodiments can remove one or more materials or components from a multi-material fluid, semi-solid, or solid to make the resulting components more easily (e.g., in terms of cost, in terms of environmental compliance, in terms of logistics) disposable relative to the disposal of the fluid, semi-solid, or solid before application of ultrasonic waves by example sonication devices. Example embodiments can be part of a newly manufactured processing facility, or alternatively example embodiments can be retrofitted into or work with an existing facility or process. Use of example embodiments described herein can provide for a more flexible process able to address a variety of oilfield needs, improve maintenance, reduce costs, and increase operating efficiency.

[0073] With respect to the embodiments disclosed herein, if a component of a figure is described but not expressly shown or labeled in that figure, the label used for a corresponding component in another figure can be inferred to that component. Conversely, if a component in a figure is labeled but not described, the description for such component can be substantially the same as the description for the corresponding component in another figure. The numbering scheme for the various components in the figures herein is such that each component is a three-digit number or a four-digit number, and corresponding components in other figures utilize the identical last two digits. For any figure shown and described herein, one or more of the components may be omitted, added, repeated, and / or substituted. Accordingly, embodiments shown in a particular figure should not be considered limited to the specific arrangements of components shown in such figure.

[0074] Further, a statement that a particular embodiment (e.g., as shown in a figure herein) does not have a particular feature or component does not mean that such embodiment is not capable of having such feature or component, unless expressly stated. For example, for purposes of present or future claims herein, a feature or component that is described as not being included in an example embodiment shown in one or moreparticular drawings is capable of being included in one or more claims that correspond to such one or more particular drawings herein.

[0075] Terms such as “first”, “second”, “on”, “upon”, “outer”, “inner”, “top”, “bottom”, and “within” are used merely to distinguish one component (or part of a component or state of a component) from another. Such terms are not meant to denote a preference or a particular orientation. Such terms are not meant to limit embodiments of sonication for separation of materials in fluids, semi-solids, or solids. In the detailed descriptions of the example embodiments, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0076] Many modifications and other embodiments set forth herein will be evident to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that example embodiments are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this application. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

CLAIMSWhat is claimed is:

1. A system comprising: a vessel comprising a bottom wall, a first side wall, and a second side wall, wherein the vessel defines a cavity for containing a base hydrocarbon mixture; a first plurality of sonication devices mounted to an exterior surface of the first side wall, wherein the first plurality of sonication devices direct first ultrasonic waves through the first side wall and into the cavity; a second plurality of sonication devices mounted to an exterior surface of the second side wall, wherein the second plurality of sonication devices direct second ultrasonic waves through the second side wall and into the cavity; an added water feed for providing added water to the vessel; a mixer disposed in the cavity for mixing the base hydrocarbon mixture with the added water to create a vessel mixture; an oil removing system for removing oil that has been separated from the vessel mixture; and at least one drainage port for removing at least a portion of the vessel mixture from the vessel.

2. The system of claim 1, wherein the first plurality of sonication devices and the second plurality of sonication devices are magnetostrictive transducers.

3. The system of claim 2, wherein the magnetostrictive transducers each comprise an electrical coil surrounding a stack of metallic plates.

4. The system of claim 1, wherein the first plurality of sonication devices are brazed to the exterior surface of the first side wall, and wherein the second plurality of sonication devices are brazed to the exterior surface of the second side wall.

5. The system of claim 1, wherein first emitting surfaces of the first plurality of sonication devices are parallel with and facing second emitting surfaces of the second plurality of sonication devices.

6. The system of claim 1, further comprising one or more heating devices, wherein the one or more heating devices is selected from: submersible conductive heaters attached to an interior of the vessel; flow through cartridge heaters attached on the exterior surface or aninterior of the vessel; and steam heat applied directly or through one or more pipes.

7. The system of claim 1, further comprising one or more of: a purge and pressurization system for hazardous environments; one or more fans to remove hazardous gases which may accumulate; and load cells to monitor weight of contents.

8. The system of claim 1, wherein the added water is heated before the added water flows into the vessel via the added water feed.

9. The system of claim 1, wherein the oil removing system is one of a skimmer or a weir.

10. The system of claim 1, wherein the mixer is a vertical mixer mounted at the top of the vessel.

11. The system of claim 1, wherein the mixer is oriented to direct the fluid mixture to flow along the bottom wall toward the first end wall and to flow along a top of the vessel toward the second end wall.

12. The system of claim 1, wherein the mixer comprises at least one of an impeller, a propeller, valves, draft tubes, eductor jets, air jets or bubblers, or inductor jets.

13. The system of claim 1, wherein the base hydrocarbon mixture and the added water are provided to the vessel at an added water to base hydrocarbon mixture ratio ranging from 1 :1 to 10:1 (weight / weight).

14. A method for separating sediment and oil from a base hydrocarbon mixture, the method comprising: introducing the base hydrocarbon mixture into a vessel, the vessel comprising a bottom wall, a first side wall, and a second side wall, wherein the vessel defines a cavity for containing the base hydrocarbon mixture; mixing the base hydrocarbon mixture and added water with a mixer disposed in the vessel to create a vessel mixture; treating the vessel mixture with ultrasonic waves, the ultrasonic waves applied by a first plurality of sonication devices mounted to an exterior surface of the first side wall and a second plurality of sonication devices mounted to an exterior surface of the second side wall; collecting the oil that has separated from the vessel mixture at the top surface of the vessel mixture; ceasing mixing and allowing the sediment to collect along the bottom wall of the vessel; draining a remaining vessel mixture from the vessel; and removing sediment from the bottom wall of the vessel.

15. The method of claim 14, wherein treating the vessel mixture includes increasing a temperature of the vessel mixture in the vessel to a range of 65°C to 95°C.

16. The method of claim 15, wherein the temperature of the vessel mixture is increased using one or more heating devices disposed in the vessel.

17. The method of claim 14, further comprising introducing the added water into the vessel at a water inlet.

18. The method of claim 17, wherein the base hydrocarbon mixture and the added water are provided to the vessel at an added water to base hydrocarbon mixture ratio ranging from 1 : 1 to 10: 1 (weight / weight).

19. The method of claim 14, wherein first emitting surfaces of the first plurality of sonication devices are parallel with and facing second emitting surfaces of the second plurality of sonication devices.

20. The method of claim 14, wherein the mixer is positioned at a top of the vessel.

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