Patent Application
20070267327
Embodiments of a heavy oil upgrading process will now be described by way of example with reference to
This detailed description of a heavy oil upgrading process is exemplary and not intended to limit the scope of the claimed heavy oil upgrading process. Immaterial variations from the precise examples set forth here are intended to be included within the scope of the claims. In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the feature being present.
Heavy oil from source 10 is transferred to tank 14 where it is mixed with solvent from tank 12. The mixture is heated (source of heat not shown) for a desired period of time; and upon completion of the reaction between the solvent and the heavy oil, the insoluble asphaltenes are separated through the separation device 16. The asphaltenes are collected and stored in tank 36 while the de-asphalted oil is transferred to Tank 24. Tank 18 contains biological reagents that are added to the contents of tank 24 where biological oxidation takes place. The biologically oxidized oil is separated from the oxidized contaminants through separator 30 and transferred to reactor 28 leaving the residue which is stored in tank 38. Chemical reagents from Tank 22 are added to the contents of reactor 28 for a chemical oxidation phase. Following the chemical oxidation, the oxidized oil is separated from the oxidation residue through separator 34. The chemical oxidation residue is transferred to storage tank 42 while the oxidized oil is transferred to distillation unit 44 where the initial de-asphalting solvent is separated from the upgraded oil through atmospheric or vacuum distillation. The solvent recovered is transferred back into Tank 12 while the upgraded oil from unit 44 is collected and stored in Tank 48.
The heavy oil upgrading process described here reduces problems associated with high asphaltenes content and high contaminants' concentrations of heavy oil. The heavy oil upgrading process provides a process for upgrading heavy oil to crude oils with characteristics that enable them to be used as refinery feedstock. The heavy oil upgrading process provides the dissolution of the heavy oil in a hydrocarbon solvent comprising of paraffinic, iso-paraffinic and/or aromatic solvents. This solvent, by virtue of its composition rejects the asphaltenes which separate from the oil as black, shiny, hard and crystalline solids. Following the separation of asphaltenes from the oil, the heavy oil upgrading process provides the application of biological and chemical reagents for the reduction of contaminants' concentration from the de-asphalted oil. An embodiment of the heavy oil upgrading process comprises the steps of solvent de-asphalting followed by bio-chemical treatments as illustrated in
The exemplary hydrocarbon solvent herein described is a mixture of straight and branch chained paraffinic and aromatic solvents ranging from C4 to C10 examples of which include butane, iso-butane, n-pentane, iso-pentane, n-heptanes iso-octane and metaxylene with iso-octane being the preferred solvent. The mixture is heated at atmospheric pressure to a desired temperature and for a time sufficient to cause dissolution of the heavy oil in the solvent. The mixture may be heated to a minimum temperature of 60° C. and a maximum temperature of 120° C., the preferred temperature being in the range of 105° C.-115° C. under reflux. The residence time may range from one hour to four hours and most preferably from two to three hours. Under these conditions, the asphaltenes are separated from the oil as insoluble crystalline black shiny solids and recovered through a proper separation device. A suitable separation device comprises gravity or vacuum filtration. The amount of asphaltenes that are typically recovered through this heavy oil upgrading process is approximately 16-20% weight of the heavy oil, although this can vary depending on the source of the heavy oil and also on the operating parameters of the de-asphalting process.
Following the de-asphalting phase of the heavy oil upgrading process, biological reagents are introduced to a reactor containing a mass of the de-asphalted oil, the minimum mass of the said de-asphalted oil being 50 g and a maximum mass being 2 kg with 750 g as the preferred mass in this example. The biological reagents are selected from agricultural wastes, examples of which comprise peat moss, canola hulls, peanut shells, soybean hulls, and cellulose. The biological reagents contain enzymes that are capable of operating at high temperatures and low pH conditions and also catalyze the oxidation of the contaminants, particularly nickel and vanadium to their respective oxides at the expense of an oxidizing agent. The addition of the oxidizing agent follows the biological reagents. The oxidizing agent may comprise oxides of metals of Group IIA such as calcium and magnesium, or oxides of metals of Group VIII such as cobalt, nickel, copper or iron as well as their combinations. Other oxidizing agents which may be used comprise oxygen, air, ozone, hydrogen peroxide, chlorine, per-acetic acid, formic acid, per-benzoic acid, benzoic acid, and acetic acid. The oxidant, when applied in a liquid form is preferentially added in a range of 0.5% volume to 5.5% volume of the heavy oil/bitumen feed, although volume percentages of between 0.1% and 7.2% are also suitable for the process.
A further embodiment of the heavy oil upgrading process is the introduction of an adsorbent selected from among materials such as: fullers' earth, alumina, zeolite, clay, silica gel, peat moss or a combination of two or more of them into the reaction chamber. Preferred adsorbents are alumina, peat moss, clay or their combinations. In one embodiment, the adsorbent is applied as a weight percentage of the heavy oil or bitumen from between 0.055% weight and 6.5% weight with the preferred range being 2.5% weight to 5.5% weight.
The biological oxidation, according to one embodiment of the heavy oil upgrading process, is carried out at pressures ranging from 1 atm to 14 atm and at temperatures ranging from 85° C. to 150° C., and over a period of time ranging between 2 and 3 hours. Following the biological oxidation of the de-asphalted oil, the oxidized oil is separated from the contaminants by means of a suitable separation device. Such a device may comprise gravity filtration, vacuum filtration, centrifugation, or pressure-leaf filtration.
A further embodiment of the heavy oil upgrading process comprises the introduction of chemical reagents to the biologically oxidized oil in a second reactor. The preferred chemical reagents comprise catalysts, examples of which comprise alumina, activated carbon, bituminous coal, lignite char or coconut char. Oxides of Group VIII metals have also been found to be useful as oxidation catalysts with the preferred such catalyst being iron oxide. As an embodiment of this heavy oil upgrading process, iron oxide is derived exclusively from a waste hydrometallurgical metal processing plant. A hydrogen donor solvent, preferably a carboxylic acid solvent may also be employed. Preferred carboxylic acids may comprise formic or acetic acid. As a further embodiment of the heavy oil upgrading process, any one of the oxidants used in the biological oxidation phase can be used in the chemical oxidation. As well, the most preferred oxidants comprise iron oxide, water, and hydrogen peroxide or a mixture of aqueous hydrogen peroxide and an acid. As another embodiment of the heavy oil upgrading process, any one of the adsorbents used in the biological oxidation phase can be used in the chemical oxidation.
The mixture of oil, chemical reagents and adsorbent may be heated to a sufficient temperature and sufficient pressure over a sufficient amount of time. These parameters comprise a temperature range of 105° C. to 180° C., pressures ranging between 1 atm and 14 atm, and times ranging from 1 hour to 3 hours. Thereafter, the chemically oxidized oil is separated from the contaminants via a separation device. Examples of such separation devices comprise gravity filtration, vacuum filtration, centrifugation and pressure filtration.
The oil recovered from the separation unit is further subjected to yet another separation system to recover the upgraded oil from the de-asphalting solvent. As an embodiment of the heavy oil upgrading process, the preferred method of separating the solvent from the upgraded oil is by either atmospheric or vacuum distillation. The solvent recovered from the distillation unit is re-used in subsequent de-asphalting phases of the upgrading process. The residual product, following the separation of the solvent is the upgraded oil which is substantially reduced in contaminants' concentration as disclosed by the results of the chemical and physical analyses of the product. As an embodiment of the heavy oil upgrading process, the chemical oxidation process can precede the biological oxidation.
This example illustrates the effect of using virgin and recycled solvent in the de-asphalting phase of the upgrading process.
In a 1 L beaker was accurately weighed 5 g of Alberta heavy oil. 100 mL of virgin solvent was added to the heavy oil to give a 20:1 solvent to oil ratio and the mixture was stirred with heat from a hot plate until the formation of an emulsion was observed. With continuous stirring, the mixture was heated to a moderate temperature and thereafter, transferred to a 3-neck round bottom 1 L flask provided with a reflux condenser and a thermometer, where the mixture was heated with further stirring for 3 hours at a temperatures ranging from 60° C. to 100° C. The mixture was allowed to cool to ambient temperature and thereafter, the asphaltenes were separated from the de-asphalted oil through filtration, and the weight of dry asphaltenes was recorded. This experiment was repeated five times and the average weight of asphaltenes determined. From the average weight of asphaltenes, the weight percent of the asphaltenes, based on the initial weight of 5 g of the heavy oil, was calculated. In similar experiments, previously used solvent was used in de-asphalting experiments as described above. The average weight of asphaltenes recovered from the five experiments with the recycled solvents was determined and the weight percent of the asphaltenes calculated. The weight percent of the asphaltenes recovered from the experiments with the virgin solvent was approximately 18% while the weight percent of the asphaltenes recovered from the experiments with the previously used solvent was approximately 13%.
The following examples are based on investigations conducted with samples of de-asphalted oil derived from composite de-asphalted oil prepared from the reaction between Alberta heavy oil and the solvent.
This example illustrates the application of a heavy oil upgrading process. Into a 3-neck IL round bottom flask was measured 350 mL sample of de-asphalted oil. 3 g of biological reagent A and 2 g of biological reagent B were added to the de-asphalted oil followed by the addition of 1 mL of oxidant. Using a magnetic stirrer, the mixture was subjected to stirring while being heated to 175° C. for 3 hours. During the reaction between the oil, the biological reagents, and the oxidant, the enzymes in the agricultural waste or the biological reagents catalytically oxidized the contaminants in the oil. This resulted in the formation of the oxides of nickel and vanadium. Following the biological oxidation, the oil was separated from the oxidized by-products through filtration. The filtrate was transferred to another 3-neck IL round bottom flask to which the chemical reagents were added. The chemical reagents included activated carbon, iron oxide oxidant, a hydrogen donor solvent, water, and the adsorbent. The mixture was subjected to chemical oxidation by heating it to a temperature range of 120° C.-140° C. for 3 hours and at pressures ranging between 1 atm and 14 atm. Following the chemical oxidation, the mixture was cooled and filtered. The oxidized contaminants from the oil, which included the oxides of the metals nickel and vanadium, were thus separated from the oil. The post-treated oil was analyzed for its contaminants concentrations. Table 1 contains the results of the analyses of the upgraded oil.
This example illustrates the effect of using biological reagents as catalysts in the upgrading process. Into a 3-neck IL round bottom flask was measured 500 mL of de-asphalted oil. Specified amounts of the two biological reagents, A and B were added followed by the addition of an oxidant. Upon heating the mixture for 2 hours at a temperature of 150° C., the mixture was cooled and filtered. The filtrate, which was a mixture of the de-asphalting solvent and the biologically upgraded oil, was subjected to a separation process from which the solvent was recovered from the upgraded oil. In a comparable experiment, 500 mL of de-asphalted oil was oxidized under the same experimental conditions as before, including the same amount of oxidant, but without any biological reagents. Following the separation of the solvent from the upgraded oil, contaminants concentrations of the two upgraded oils were determined. The results are contained in Table 2.
Tables 3 and 4 contain some physical and chemical data of upgraded crude oils with characteristics of a refinery feedstock produced from the bio-chemical catalytic oxidation process of the present heavy oil upgrading process.
Table 4 contains a summary by carbon of the fractional composition of a crude oil produced by the bio-chemical catalytic oxidation of Alberta heavy oil.
In one embodiment, a heavy oil upgrading process provides further a bio-chemical catalytic oxidation process for obtaining, from heavy oils and bitumen containing 6.20% weight of sulphur and 0.30% weight of nitrogen as well as 45 ppm of nickel and 128 ppm of vanadium, an upgraded oil containing a minimum of 50% of the original contaminants.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2549791 | May 2006 | CA | national |
| 2549358 | May 2006 | CA | national |
