Pelletization of a source oil

Abstract

The invention provides methods for treating a source oil phase to form continuous or discrete solid oil volumes.

Description

PELLETIZATION OF A SOURCE OILFIELD OF THE INVENTION

[0001] The invention is in the field of methods for producing solid volume or volumes of a liquid oil.BACKGROUND OF THE INVENTION

[0002] Typically, petroleum substances with high viscosity and density fall into one of three categories: "heavy oil" and "extra heavy oil" or “asphalt binder” Generally, "heavy oil" refers to petroleum with a mass density ranging from about 920 kg / m3(or an API gravity around 26°) to 1 ,000 kg / m3(or an API gravity around 10°). Extra heavy oil, also known to as bitumen in the context of oil sands reservoirs, is typically described as the part of petroleum existing in semi-solid or solid phases in natural deposits, with a mass density exceeding about 1 ,000 kg / m3(or an API gravity around 10° or lower) and a viscosity surpassing 10,000 centipoise (cP or 10 Pa.s) measured at the original deposit temperature and atmospheric pressure, on a gas-free basis. Asphalt binder, sometimes referred to as bitumen in the context of the asphalt and paving industry, is a more viscous oil product than extra heavy oil with viscosity exceeding of order of 5,000,000 cP at ambient (~21°C) temperature.

[0003] Though commonly used, the terms "heavy oil" and "extra heavy oil" and “asphalt binder” serve as convenient categories, and there exists a continuum of properties between them. Thus, references to heavy oil and / or extra heavy oil and / or asphalt binder encompass this continuum, without implying a rigid, universally recognized boundary between the three. Specifically, "heavy oil" encompasses all forms of "extra heavy oil" and “asphalt binder” including hydrocarbons existing in semi-solid or solid states. Likewise, a "bituminous" material includes a bitumen component, broadly defined.

[0004] In numerous heavy oil and extra heavy oil processing operations, it is mixed with a lighter solvent to facilitate various processes, such as separation from water ortransportation through pipelines. In its natural state with no heating, heavy oil or extra heavy oil possesses too high a viscosity to be efficiently pumped through pipelines. For instance, in certain pipelines, the oil's viscosity must match or be lower than 250 or 350 cSt.

[0005] Another method for enabling the flow of heavy oil or extra heavy oil or asphalt binder is to heat them until their viscosity drops to a value where it can be pumped.

[0006] Another method for transporting heavy oil or extra heavy oil or asphalt binder is to convert them to solid and transporting them as a dry good.

[0007] There is an ongoing need for improved methods that are both relatively efficient and simple to create small volumes of the solid heavy oil or extra heavy oil or asphalt binder, in the form of pellets, that are relatively easy to transport as a dry good.

[0008] The pellets of heavy oil or extra heavy oil or asphalt binder can be placed into bags or containers for transport.SUMMARY OF THE INVENTION

[0009] In one aspect of the present invention, a source oil, such as an asphalt binder is pumped from a tank or vessel where it is maintained at elevated temperature to reach a target viscosity, and is then flowed through exits in an extrusion die at a target temperature with subsequent cooling that enables a glass transition of the source oil, creating a continuous extrudate that has a solid external layer. In select embodiments, the temperature and shear rate are controlled so that the viscosity of the oil is <10,000 cP and preferably <300 cP when entering the extrusion die, and the temperature of the extrusion die is maintained <50°C or <20°C and preferably <10°C above the glass transition temperature of the oil. In this way, the present methods accordingly facilitate rapid transition of the oil to glass (solid) when exiting the die, due to cooling whether as an extrudate or droplets. An aspect of this process is that the oil, near its glass transition temperature, is sheared on exiting the die or nozzle, and as such, at a molecular scale, the oil ‘particles’ are ordered as they leave the die leading to the greater propensity for forming a glass (solid). The continuous extrudate may then placed on a surface, suchas a wire mesh conveyor, where coolant, such as a continuous air flow, further removes heat from the continuous extrudate converting the moving volume on the conveyor of the extrudate to a solid.

[0010] The continuous extrudate may then be cut or segregated into volumes of specified length by using standard cutting methods.

[0011] In another aspect of the invention, a water mist or other coolant can be sprayed on the continuous extrudate to enable further cooling of the extrudate.

[0012] In another aspect of the invention, the conveyor can be a cooled belt or wire mesh or other support material.

[0013] The methods disclosed here include a precise control of the temperature that enables flow from the extrusion die openings within a specified range of temperature such that on exiting the openings of the extrusion die, natural or forced cooling by exposure to the ambient environment enables cooling of the outer layer of the extrudate to a glass. The ambient environment can for example be still or moving air.

[0014] The methods disclosed here include the design of the extrusion die such that the openings that produce the extrudate produce a continuous extrudate with diameter or average dimension that permits the cooling of the outer layer of the extrudate when exiting the extrusion die opening to enable the glass transition of the extrudate. For asphalt binders, the average diameter of the extrudate would be preferred to be less than 2 cm and preferably less than 1 cm.

[0015] The methods described here include the design of the extrusion die to enable uniform distribution of the asphalt binder across the span of the extrusion die. The width of the extrusion die and number of openings on the extrusion die can be adjusted to the required overall flow rate of the system.

[0016] The openings of the extrusion die can be designed to achieve different final shapes of the extrudate. The preferred shape is a circle which produces a continuous cylindrical extrudate.

[0017] In another embodiment of the method, the asphalt binder is sprayed from a nozzle forming droplets of a specified size which cool when exposed to the outerenvironment such that the outer skin of the droplet is cooled passing through the glass transition temperature.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a diagram exemplifying one implementation of the method described herein for treating a source oil phase and converting it into discrete volumes of the oil in a glassy rigid state.

[0019] FIG. 2 is a diagram exemplifying another implementation of the method described herein for treating a source oil phase and converting it into discrete volumes of the oil in a glassy rigid state.DETAILED DESCRIPTION OF THE INVENTION

[0020] Methods are provided for creating discrete solid volumes of a source oil where the temperature is controlled from the point of formation of the source oil leading to cooling which enables the temperature to pass through the glass transition temperature leading to the formation of a solid that is glassy and rigid.

[0021] In the method disclosed here, the glass transition point of the source oil is measured. For an asphalt binder, the glass transition point is typically in the range from 30 to 100°C.

[0022] In one embodiment, illustrated in FIG. 1 , the method can be accomplished by pumping the source oil from a tank at temperature 100 to 200°C above the glass transition temperature. The tank is stored so that its shear rate is high enough to maintain its viscosity at the temperature of the tank at below 10,000 cP and preferably below 3,000 cP, and most preferably below 300 cP. The tank also prevents flow perturbations from the upstream process affecting the downstream flow.

[0023] The source oil in the tank is then pumped at a shear rate high enough to maintain the viscosity of the source oil below 10,000 cP and preferably below 3,000 cP, and most preferably below 300 cP into an extrusion die where the temperature of the source oil in the extrusion die is controlled to be within a few degrees above the glasstransition temperature. When the source oil extrudate flows from the openings in the extrusion die, it further cools on exposure to the environment so that the outer layer of the extrudate drops lower than the glass transition temperature leading to a solid layer on the outer layer of the extrudate. The environment can be ambient air. Thereafter the extrudate is placed on a wire mesh conveyor through which air flows past the extrudate leading to further cooling of the extrudate leading to a glass transition of the entire volume of the extrudate. The extrudate is then cut into pieces.

[0024] The temperature of the source oil in the extrusion die is maintained at most 50°C above the glass transition temperature and preferably is between 10 and 20°C above the glass transition temperature. Most preferably, the temperature of the source oil in the extrusion die is maintained between 5 and 10°C above the glass transition temperature.

[0025] In the device described here, the openings of the extrusion die are specified so that the cross-sectional diameter of the extrudate is small enough to enable efficient heat transfer from the extrudate to the air such that cooling occurs within 30 minutes and preferably within 1 minute. The openings of the extrusion die are preferred to be smaller than 2 cm in diameter and preferably less than 1 cm in diameter and most preferably less than 0.5 cm in diameter.

[0026] The number of openings in the extrusion die is selected to achieve an overall flow rate.

[0027] In the device described here, the air flow past the extrudate through the wire mesh conveyor is controlled such that the extrudate is cooled below the glass transition temperature.

[0028] In another embodiment, the cooling can be done on a chilled belt.

[0029] In another embodiment of the device, a water mist is sprayed on the extrudate to accelerate its cooling.

[0030] In another embodiment of the device, as displayed in FIG. 2, the source oil is sprayed from a nozzle forming droplets in a cooling environment such as air or water. The source oil temperature in the nozzle is maintained at most 50°C above the glasstransition temperature and preferably is between 10 and 20°C above the glass transition temperature. Most preferably, the temperature of the source oil in the extrusion die is maintained between 5 and 10°C above the glass transition temperature.

[0031] In the device described here, the sprayed droplets are cooled in the environment such that the temperature drops below the glass transition temperature.

[0032] For the methods described here, the environment into which the extrudate or droplets are placed can be air, water, or an inert gas. Example inert gases include nitrogen or carbon dioxide.

[0033] Although various embodiments of the invention are disclosed herein, many adaptations and modifications may be made within the scope of the invention in accordance with the common general knowledge of those skilled in this art. Such modifications include the substitution of known equivalents for any aspect of the invention in order to achieve the same result in substantially the same way. Numeric ranges are inclusive of the numbers defining the range. The word "comprising" is used herein as an open-ended term, substantially equivalent to the phrase "including, but not limited to", and the word "comprises" has a corresponding meaning. As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a thing" includes more than one such thing. Citation of references herein is not an admission that such references are prior art to the present invention. Any priority document(s) and all publications, including but not limited to patents and patent applications, cited in this specification are incorporated herein by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein and as though fully set forth herein. The invention includes all embodiments and variations substantially as hereinbefore described and with reference to the examples and drawings.

Claims

CLAIMS1 . A method of treating a source oil comprising: maintaining the source oil in a source oil vessel at a source oil temperature and source oil shear rate, the source oil having a measured glass transition temperature; pumping the source oil in a uniform source oil phase through an extrusion die, wherein the extrusion die is maintained at an extrusion die temperature that is <50°C above the glass transition temperature of the source oil, wherein the source oil temperature, the source oil shear rate and the extrusion die temperature are selected so that viscosity of the source oil phase in the extrusion die is less than 10,000 cP; continuously extruding the source oil phase from the extrusion die to form a continuous extrudate; cooling the extrudate in a cooling environment so that an outer layer of the extrudate drops below the glass transition temperature to form a solid outer layer.

2. The method of claim 1 , further comprising: passing the extrudate having the solid outer layer onto a further cooling environment to further cool an internal volume of the extrudate to below the glass transition temperature, forming a glassy rigid extrudate.

3. The method of claim 2, further comprising segregating the glassy rigid extrudate into smaller glassy rigid pieces.

4. The method of any one of claims 1 -3, wherein the further cooling environment comprises a wire mesh or chilled conveyor surface supporting the extrudate during further cooling.

5. The method of any one of claims 1 -4, where the source oil comprises a heavy oil, an extra heavy oil, a vacuum residue, an asphalt binder, or a mixture thereof.

6. The method of any one of claims 1 to 5, where the extrusion die temperature is <20°C or <10°C above the glass transition temperature.

7. The method of any one of claims 1 to 6, where the cooling environment comprises a cooling fluid.

8. The method of claim 7, wherein the cooling fluid comprises air, water, an air and water mist, or an inert gas.

9. The method of any one of claims 1-8, the source oil temperature, the source oil shear rate and the extrusion die temperature are selected so that viscosity of the source oil phase in the extrusion die is less than 300 cP.

10. A method of treating a source oil comprising: maintaining the source oil in a source oil vessel at a source oil temperature and source oil shear rate, the source oil having a measured glass transition temperature; pumping the source oil in a uniform source oil phase through a spray nozzle, wherein the spray nozzle is maintained at a spray nozzle temperature that is <50°C above the glass transition temperature of the source oil, wherein the source oil temperature, the source oil shear rate and the spray nozzle temperature are selected so that viscosity of the source oil phase in the extrusion die is less than 10,000 cP; continuously spraying the source oil phase from the spray nozzle to form a continuous stream of droplets;cooling the droplets in a cooling environment so that the droplets are cooled below the glass transition temperature to form solid glassy droplets.

11. The method of claim 10, where the source oil comprises a heavy oil, an extra heavy oil, a vacuum residue, an asphalt binder, or a mixture thereof.

12. The method of claim 10 or 11 , where the spray nozzle temperature is <20°C or <10°C above the glass transition temperature.

13. The method of any one of claims 10-12, where the cooling environment comprises a cooling fluid.

14. The method of claim 13, where the cooling fluid comprises air, water, an air and water mist, or an inert gas.

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