Patent Application
20110180454
The upgrading of heavier hydrocarbon material into useful commercial products can be achieved according to many different processes, such as through the use of fluid catalytic crackers, hydrocrackers, cokers, visebreaking units, and nozzle reactors. However, the conversion rate of certain hydrocarbons in some upgrading units into lighter, more useful hydrocarbons is not always sufficiently high to make the process of upgrading the hydrocarbons economical.
For example, the upgrading of solid asphaltene found in the tailings produced by a froth treatment process of extracting bitumen from oil sands and the like can be difficult. In the froth treatment process, oil sands or the like are mixed with hot water and then agitated to form a bitumen-enriched froth. The combination of hot water and agitation releases bitumen from the oil sands, and allows small air bubbles to attach to the bitumen droplets. The bitumen-loaded air bubbles float to the top of the mixture to form a bitumen-enriched froth. The bitumen-enriched froth is then separated from the mixture and subjected to further treatment in order to separate the bitumen from any other materials included in the bitumen-enriched froth, such as mineral solids and water. This treatment often includes adding a hydrocarbon solvent, such as an aliphatic solvent, to the froth in order to modify the viscosity of the bitumen and facilitate its separation from the other components of the froth. Once the bitumen has been separated, tailings are left behind that include mineral solids, water, solvent, and asphaltenes that have precipitated upon introduction of the aliphatic solvent.
The tailings produced by bitumen extraction methods such as the forth treatment described above may undergo processing to separate the various components of the tailings, including the separation of solid asphaltenes included in the tailings. Methods for accomplishing this separation are disclosed in U.S. Pat. No. 7,585,407 and U.S. Published Application No. 20080156702. In the '407 patent, the method can include introducing a gas into the tailings to form an asphaltene froth, separating a water and asphaltene mixture from the froth, and adding a hydrophobic agglomeration agent into the mixture to form asphaltene particles. In the '702 application, the method can include the use of cyclonic separation methods to separate a mixture of solvent and asphaltene from the tailings and to separate the solvent and the asphaltene.
Attempts to upgrade solid asphaltenes obtained from tailings by methods such as those described above using traditional upgrading units have largely been unsuccessful. Absent the development of more successful upgrading units or pre-treatments steps that can be carried out on the asphaltenes to increase the conversion rate inside typical upgrading units, the asphaltenes are often discarded as a waste product of the froth treatment process.
Disclosed are embodiments of various methods for preparing solid hydrocarbons for upgrading in a nozzle reactor.
In some embodiments, the method includes preparing a mixture including solid hydrocarbon dissolved in a first solvent. The method also includes injecting the liquid mixture into a nozzle reactor.
In some embodiments, the method includes precipitating solid asphaltene from a bitumen source. The method also includes preparing a mixture of the solid asphaltene dissolved in a light aromatic solvent. The ratio of light aromatic solvent to solid asphaltene in the mixture can range from 0.25:1 to 4:1 on a weight basis. The method also includes centrifuging the mixture. The method also includes injecting the centrifuged mixture into a nozzle reactor.
In some embodiments, the method includes mixing a first quantity of solid hydrocarbon with a first quantity of first solvent to create a first mixture. The method also includes adding the first mixture to a second quantity of solid hydrocarbon to create a second mixture. The method also includes injecting the second mixture into a nozzle reactor.
It is to be understood that the foregoing is a brief summary of various aspects of some disclosed embodiments. The scope of the disclosure need not therefore include all such aspects or address or solve all issues noted in the background above. In addition, there are other aspects of the disclosed embodiments that will become apparent as the specification proceeds.
The foregoing and other features, utilities, and advantages of the subject matter described herein will be apparent from the following more particular description of certain embodiments as illustrated in the accompanying drawings. In this regard, it is to be understood that the scope of the invention is to be determined by the claims as issued and not by whether given subject includes any or all features or aspects noted in this Summary or addresses any issues noted in the Background.
The preferred and other embodiments are disclosed in association with the accompanying drawings in which:
Before describing the details of the various embodiments herein, it should be appreciated that the terms “solvent,” “a solvent” and “the solvent” can include one or more than one individual solvent compound unless expressly indicated otherwise. Mixing solvents that include more than one individual solvent compound with other materials can include mixing the individual solvent compounds simultaneously or serially unless indicated otherwise. It should also be appreciated that, as used herein, the term “tar sands” includes oil sands. The separations described herein can be partial, substantial or complete separations unless indicated otherwise. All percentages recited herein are weight percentages unless indicated otherwise.
With reference to
With reference to the step 100 of preparing a mixture including solid hydrocarbon dissolved in a first solvent, the preparation of the mixture generally includes combining a solid hydrocarbon with a first solvent such that a portion, and preferably all, of the soluble solid hydrocarbon dissolves in the first solvent to thereby create a mixture containing first solvent and dissolved hydrocarbon. In some embodiments, the mixture is predominantly liquid, but also includes some solids. The liquid component of the mixture includes the first solvent and the portion of the solid hydrocarbon dissolved therein. The solid component includes non-dissolved solid hydrocarbon and any other solid particulate that does not dissolve in the solvent. The solid particulate can include materials such as silica and clay found in the source of the solid hydrocarbon material but which were not separated from the solid hydrocarbon material prior to preparing the mixture of solvent and solid hydrocarbon material.
The type of solid hydrocarbon suitable for use in step 100 is not limited. In some embodiments, the solid hydrocarbon is a relatively heavy hydrocarbon material, such as those hydrocarbons having a molecular weight in the range of from 1,500 to 5,000. In some embodiments, the solid hydrocarbon is oil-derived solid hydrocarbon.
In some embodiments, the solid hydrocarbon is solid asphaltene. The source of the solid asphaltene suitable for use in this method is not limited. In some embodiments, the solid asphaltene is obtained from tailings produced during a bitumen extraction process, such as a forth treatment process. As described in greater detail above in the Background, tailings produced by a froth treatment process for extracting bitumen from bituminous material can include precipitated solid asphaltenes along with other inorganics, such as silica and clay. Accordingly, the precipitated solid asphaltenes can be separated from the other components of the tailings in order to serve as the solid hydrocarbon used in the method described herein. In some embodiments, the solid asphaltene is obtained from any deasphalting process known to those of ordinary skill in the art and which yields a solid asphaltene component as part of the deasphalting process. Exemplary deasphalting processes include, but are not limited to, the Residual Oil Supercritical Extraction (ROSE) process and more conventional propane deasphalting processes.
In some embodiments, the solid hydrocarbon used in the preparation of the mixture includes other non-hydrocarbon materials. For example, when the solid hydrocarbon is solid asphaltene separated from froth treatment tailings, the asphaltene mixed with the solvent may include various components of the tailings as a result of the difficulty in cleanly separating only the asphaltene from the tailings. In one non-limiting example, the asphaltene used in the preparation of the mixture has a composition as set forth below in Table 1.
The clay, silica, iron oxide, and titanium dioxide all represent components of the tailings from which the asphaltene was derived. In some embodiments, these four components are referred to as “ash”.
The first solvent suitable for use in this method can be any solvent capable of dissolving a solid hydrocarbon. In some embodiments, the first solvent includes a hydrocarbon solvent or mixture of hydrocarbon solvents. The hydrocarbon solvent or mixture of hydrocarbon solvents can be economical and relatively easy to handle and store. The hydrocarbon solvent or mixture of hydrocarbon solvents may also be generally compatible with refinery operations.
In certain embodiments, the first solvent is a light aromatic solvent. The light aromatic solvent can be an aromatic compound having a boiling point temperature less than about 400° C. at atmospheric pressure. In some embodiments, the light aromatic solvent used in step 100 is an aromatic having a boiling point temperature in the range of from about 75° C. to about 350° C. at atmospheric pressure, and more specifically, in the range of from about 100° C. to about 250° C. at atmospheric pressure. In some embodiments, the light aromatic solvent has a boiling temperature less than about 200° C.
It should be appreciated that the light aromatic solvent need not be 100% aromatic compounds. Instead, the light aromatic solvent may include a mixture of aromatic and non-aromatic compounds. For example, the first solvent can include greater than zero to about 100 wt % aromatic compounds, such as approximately 10 wt % to 100 wt % aromatic compounds, or approximately 20 wt % to 100 wt % aromatic compounds.
Any of a number of suitable aromatic compounds can be used as the first solvent. Examples of aromatic compounds that can be used as the first solvent include benzene, toluene, xylene, aromatic alcohols, and combinations and derivatives thereof. The first solvent can also include compositions, such as kerosene, diesel (including biodiesel), light gas oil, light distillate, commercial aromatic solvents such as Aromatic 100, Aromatic 150, and Aromatic 200, and/or naphtha.
Preparation of the mixture can be carried out in any suitable manner for dissolving the solid hydrocarbon in the solvent. Preparation of the mixture may include any type of agitation to promote dissolution of the solid hydrocarbon in the solvent, such as mixing. When preparing the mixture in a vessel, the solid hydrocarbon and solvent can be added to the vessel separately, simultaneously, in any order, and in incremental portions or all at once.
The amount of solvent and solid hydrocarbon used to prepare the mixture can be any amount which results in at least a portion of the soluble solid hydrocarbon dissolving in the solvent. In some embodiments, the ratio of first solvent to solid hydrocarbon in the mixture ranges from about 0.25:1 to about 4:1 on a weight basis.
Once the mixture has been prepared, the method may optionally include a step of separating non-dissolved solids from the mixture prior to performing step 110 of injecting the mixture into a nozzle reactor. Removal of non-dissolved solids from the mixture is suitable when the nozzle reactor into which the mixture is to be injected has a relatively small injection opening or an opening that is smaller than the size of the any of the non-dissolved solid particles present in the mixture. Conversely, the optional separation step can be bypassed when the injection opening of the nozzle reactor is relatively large or larger than the non-dissolved solid particles in the mixture.
The mixture can include any of a number of non-dissolved solid particles. For example, when solid asphaltenes from the tailings produced during a bitumen extraction forth treatment process are used in the method, the solid asphaltenes used in preparing the mixture can include inorganic solids, such as the various components of the ash described in greater detail above. These inorganic solids can be present in the mixture when the solid asphaltenes are not completely separated from the tailings prior to being used in the preparation of the mixture.
Any suitable manner of separating the non-dissolved solids from the mixture may be used in the method described herein. In some embodiments, a centrifuge is used in order to separate non-dissolved solids from the mixture. Other separation techniques include the use of a filter, wherein the mixture including solid hydrocarbon dissolved in a first solvent passes through a filtration medium while the non-dissolved solids are not permitted to pass through the filtration medium.
In some embodiments, both step 100 and the optional separation step described above are repeated one or more times. More specifically, the solvent having hydrocarbon dissolved therein that is separated from non-dissolved solid particles in a separation unit is combined with further solid hydrocarbon material to form a further mixture, and the further mixture is then be passed through the separation unit again to remove any non-dissolved solid particles contained in the further mixture. This series of steps can be performed any number of times in an attempt to dissolve as much solid hydrocarbon material in the solvent as possible and remove as much non-dissolved solid particles from the mixture as possible. The repeated steps of preparing the mixture and separating the non-dissolved solid particles from the mixture can be similar or identical to the initial steps of preparing the mixture and separating the non-dissolved solid particles from the mixture described above.
With reference to
The solvent and dissolved hydrocarbon 221 sent back to the vessel 210 dissolve further solid hydrocarbon material 212 added to the vessel. Additional solvent 211 can also be added to the vessel, but in some embodiments, no additional solvent 211 is required. The mixture thus formed in the vessel 210 is sent to the separation unit 220 and the process described is repeated again. After a desired number of cycles, the solvent and dissolved bitumen 221 exiting the separation unit are sent to a nozzle reactor rather than recycling the solvent and dissolved bitumen 221 back the vessel 210.
After preparation of the mixture and optional separation of non-dissolved solids from the mixture, the mixture is injected into a nozzle reactor for the purpose of upgrading the solid hydrocarbon dissolved in the solvent. Nozzle reactors generally include any apparatus capable of allowing for the injection of differing types of materials into a reactor chamber in the nozzle reactor to cause the materials to interact within the reactor chamber and achieve alteration of the mechanical or chemical composition of one or more of the materials. Any suitable nozzle reactor can be used in the method described herein. In some embodiments, the nozzle reactor is similar or identical to the nozzle reactor described in U.S. Pat. No. 7,618,597, the entirety of which is hereby incorporated by reference.
One nozzle reactor disclosed in U.S. Pat. No. 7,618,597 is illustrated in
With continuing reference to
In certain embodiments, the side wall of the injection passage 15 can provide one or more among: (i) uniform axial acceleration of cracking material passing through the injection passage; (ii) minimal radial acceleration of such cracking material; (iii) a smooth finish; (iv) absence of sharp edges; and (v) absence of sudden or sharp changes in direction. The side wall configuration can render the injection passage 15 substantially isoentropic. These latter types of side wall and injection passage features can be, among other things, particularly useful for pilot plant nozzle reactors of minimal size.
A material feed passage 18 extends from the exterior of the reactor body 14 toward the interior reactor chamber 16. In the embodiment shown in
The annular material feed port 20 may have a U-shaped or C-shaped cross-section among others. In certain embodiments, the annular material feed port 20 is open to the interior reactor chamber 16, with no arms or barriers in the path of fluid flow from the material feed passage 18 toward the interior reactor chamber 16. The junction of the annular material feed port 20 and material feed passage 18 can have a radiused cross-section.
In alternative embodiments, the material feed passage 18, annular material feed port 20, and/or injection passage 15 have differing orientations and configurations, and there can be more than one material feed passage and associated structure. Similarly, in certain embodiments the injection passage 15 is located on or in the interior reactor chamber side 23 (and if desired may include an annular cracking material port) rather than at the reactor body injection end 12 of the reactor body 14, and the annular material feed port 20 is non-annular and located at the reactor body injection end 12 of the reactor body 14.
In the embodiment shown in
As indicated by the drawing gaps 38, 40 in the embodiment shown in
With reference now to
The tubular body 51 of the insert end 50 may be secured within and adjacent to the interior periphery 64 of the reactor body 44. The mechanism for securing the insert end 50 in this position may consist of an axially-extending nut-and-bolt arrangement (not shown) penetrating co-linearly mating passages (not shown) in: (i) an upper radially extending lip 66 on the reactor body 44; (ii) an abutting, radially outwardly extending thickened neck section 68 on the insert end 50; and (iii) in turn, the abutting injector nozzle 52. Other mechanisms for securing the insert end 50 within the reactor body 44 may include a press fit (not shown) or mating threads (not shown) on the outer periphery 62 of the tubular body 51 and on the inner periphery 64 of the reactor body 44. Seals, e.g., 70, may be mounted as desired between, for example, the radially extending lip 66 and the abutting the neck section 68 and the neck section 68 and the abutting injector nozzle 52.
The non-linear injection passage 60 may have, from an axially-extending cross-sectional perspective, mating, radially inwardly curved opposing side wall sections 72, 74 extending along the axial length of the non-linear injection passage 60. The entry end 76 of injection passage 60 may provide a rounded circumferential face abutting an injection feed tube 78, which can be bolted (not shown) to the mating planar, radially outwardly extending distal face 80 on the injection nozzle 52.
In the embodiment shown in
The injection passage 60 can thus be configured to present a substantially isoentropic or frictionless configuration for the injection nozzle 52. This configuration may vary, however, depending on the application involved in order to yield a substantially isoentropic configuration for the application.
The injection passage 60 may be formed in a replaceable injection nozzle insert 90 press-fit or threaded into a mating injection nozzle mounting passage 92 extending axially through an injection nozzle body 94 of the injection nozzle 52. The injection nozzle insert 90 may preferably be made of hardened steel alloy, and the balance of the nozzle reactor 100 components other than seals, if any, may preferably be made of steel or stainless steel.
In the particular embodiment shown in
The interior peripheries 89, 91 of the insert end 50 and the tubular central section 46, respectively, cooperatively provide a stepped or telescoped structure expanding radially outwardly from the injection end 88 of the injection passage 60 toward the frustoconical end 48 of the reactor body 44. The particular dimensions of the various components, however, will vary based on the particular application for the nozzle reactor, generally 100. Factors taken into account in determining the particular dimensions include the physical properties of the cracking gas (density, enthalpy, entropy, heat capacity, etc.) and the pressure ratio from the entry end 76 to the injection end 88 of the injection passage 60.
Based on the nozzle reactor illustrated in
The product leaving the nozzle reactor upon upgrading of the hydrocarbon content of the mixture includes hydrocarbons having a lower molecular weight than the molecular weight of the solid hydrocarbon used in preparing the mixture. These upgraded hydrocarbons may then be used either directly as commercially useful product (e.g., solvent, fuel, etc.) or may be subjected to further upgrading to arrive at commercially useful product. In some embodiments, the conversion rate of hydrocarbons entering the nozzle reactor into lighter hydrocarbons is greater than 70%, more preferably greater than 90%, and most preferably greater than 98%.
These conversion rates represent a significant improvement over methods where the hydrocarbon material is not first dissolved in a solvent prior to injection into a nozzle reactor, which typically have conversion rates in the range of 20% to 40%. The Applicant believes that the increase in conversion rates is due at least partly to the high concentration of high boiling point hydrocarbons (e.g., asphaltenes) in the mixture fed into the nozzle reactor (around 50% as compared to around 20% for previous methods) and the significantly higher high boiling point hydrocarbon concentration per unit of reactor volume that are achieved with the method described herein as compared to previously known methods.
Additionally, the applicant believes that the boiling point temperature profile of the mixture also plays a role in increased conversion. The feed to the nozzle reactor consists of a mixture of two separate components each having a very different boiling point. The low temperature boiling point hydrocarbon component (i.e., the solvent) will immediately vaporize as it enters the nozzle reactor and, as such, the vapor molecules will not be not affected by the reactor shock waves. The high boiling point component, on the other hand, will remain in a liquid phase upon introduction into the reactor and will be subjected to shock waves within the nozzle reactor. Consequently, the low boiling point material will not crack and the high boiling point component will crack into lighter hydrocarbon molecules.
Optionally, the system 400 includes a separation vessel 420 that is suitable for separating any non-dissolved solids from mixture 413 prior to injecting the mixture 413 into the nozzle reactor 430. The separation vessel 420 includes an outlet stream 422 for the separated non-dissolved solids. When the separation vessel 420 is utilized, the mixture 413 is passed into the separation vessel 420 and separated into a cleaned mixture 421 and a non-dissolved solids stream 422.
The mixture 413 or cleaned mixture 421 is then be passed to the nozzle reactor 430. When the mixture 413 or cleaned mixture 421 is injected into the nozzle reactor 430, a cracking material 431 is also be injected into the nozzle reactor 430. The nozzle reactor 430 shown in
34.75 kg of an Athabasca asphaltene concentrate that contained concentrated hydrocarbon values present in a TSRU tails derived from the commercial processing of a froth bitumen concentrate using a paraffinic froth treatment process as described in U.S. Pat. No. 6,007,709 was mixed in a mixing tank with 33.62 kg of Aromatic 150. After one hour of mixing the solvent slurry was transported to a centrifuge were 36.7 kg of supernatant liquor was separated from 18.57 kg of inorganic solids together with 12.01 kg of entrained solvent. The mass balance for this process is shown below.
17.2 kg of the supernatant liquor was processed in a nozzle reactor as described above and shown in
The mass balance results for the process are set forth below.
The amount of gas produced was about 12 wt % (2.1 kg) and about 4 wt % carbon due to the severity of the process.
Based on a pitch fall of only 0.7% this run demonstrated that the conversion of asphaltene into liquid product was 60 wt % with an overall conversion in excess of 96 wt %. Also note that the gravity of the combined product (Middle Distillates in T-126 plus Light Distillates in T-132) had an API of 22, which means (assuming total recovery of the Aromatic 150) that the asphaltenes with a −6.6 API are producing distillate with 14.1 API.
A second run was carried out similar to the method described above in Example 1, with the exception that the residence time in the reaction section was halved. The mass balance for this run is shown below. In this case, despite having a shorter residence time, the amount of gas produced was the same as in the previous case (12 wt %) with about 3 wt % coke formation.
The pitch fall for this mixed feed run was higher at 2.73 kg, but it was still only about 14% of the total product. Furthermore, the quality of the pitch was such that this very soft material, while already partially cracked, could readily be recycled given its high hydrogen content (8.67 wt %). Again, it was noted that the gravity of the combined product had an API of 20.5, slightly lower than the previous run.
Experimentation was conducted using two different solvents. The experimentation was carried out using a set up similar to that shown in
Results obtained when toluene was used as the solvent were conducted. The results below show the results after the fifth recycle with toluene.
Testing with Aromatic 150 was then performed. The results show the results after the second recycle with Aromatic 150.
As can be seen, higher solids loading could be obtained with Aromatic 150 (49.3% solids) than with toluene (4.14% solids).
In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.
