WO2010008750A2

WO2010008750A2 - Recovery of liquid hydrocarbons

Info

Publication number: WO2010008750A2
Application number: PCT/US2009/047741
Authority: WO
Inventors: Joseph Jump
Original assignee: Novozymes A/S
Priority date: 2008-06-24
Filing date: 2009-06-18
Publication date: 2010-01-21
Also published as: WO2010008750A3

Abstract

The present invention is directed to methods for obtaining hydrocarbon materials comprising contacting a hydrocarbon starting material with an aqueous phase comprising a non-heme containing haloperoxidase and hydrogen peroxide, and separating liquid hydrocarbon from the aqueous phase. The present invention is also directed to a process of recovering liquid hydrocarbons, comprising contacting a hydrocarbon staring material with a vanadium haloperoxidase and hydrogen peroxide, and separating the liquid hydrocarbon from the aqueous phase.

Description

RECOVERY OF LIQUID HYDROCARBONS

FIELD OF THE INVENTION

The present invention relates to a process for recovering liquid hydrocarbons.

BACKGROUND OF THE INVENTION A substantial amount of the known fossil hydrocarbon/oil reserves belong to the "heavy oil" class, which includes bitumen, tar sand and oil shale. Although these reserves constitute a very significant energy source, their recovery presents significant problems, for example, due to a high content of asphaltene which gives rise to an extremely high viscosity and due to a high content of metals such as vanadium and nickel which are deleterious as they can negatively impact the downstream catalysts used during cracking and hydrotreatment.

Various upgrading technologies have been proposed for rendering heavy oils more amenable to recovery, e.g., by reducing the viscosity, corrosivity and/or density of heavy oils. Such technologies include, e.g., dilution with alkaline solvents, such as, natural gas condensate (pentane and higher alkanes), oil-in-water emulsion with surfactants or polymers, and heating. See, e.g., US Patent App. 20060014654, US Patent No. 5,904,839, US Patent No. 4,795,478. CA Patent No. 940853, CA Patent No. 2232929, US Pat No. 5,876,592, Xu et al., (2001 ), Eur. J. Biochem. 268, 4169-4176; and Romanova, et al. (2003), Internatl. Petroleum Conf. Calgary, June 12-14, 2003, paper 2003-010.

The use of enzymes in upgrading heavy oil has also been proposed. P.M. Fedorak et al., Enzyme Microb. Technol., 1993, 15 (5), 429-437, reports that chloroperoxidase can alter components in the asphaltene fraction of petroleum and is effective for metal removal. Mogollon et al., Applied Biochemistry and Biotechnology, 70-72, 765-777 (1998) reports that chloroperoxidase was able to alter asphaltene fractions and remove heavy metals (Ni and V). R. Vazquez-Duhalt et al., Enzyme Microb. Technol., 1992, vol. 14, October, 837-841 mentions investigations to determine the effect of peroxidase on asphaltenes in organic solvents.

SUMMARY OF THE INVENTION

One aspect of the present invention is directed to a process of recovering liquid hydrocarbon comprising contacting a hydrocarbon starting material with an aqueous phase comprising a non-heme containing haloperoxidase and hydrogen peroxide, and recovering liquid hydrocarbon. Another aspect of the present invention provides a process of recovering liquid hydrocarbons, comprising contacting a hydrocarbon staring material with a vanadium haloperoxidase and hydrogen peroxide, and recovering liquid hydrocarbon.

DETAILED DESCRIPTION OF THE INVENTION

The enzymatic treatment of the invention is applied to improve the recovery of hydrocarbons (e.g. fossil fuels), such as, fossil hydrocarbon/oil reserves belonging to the "heavy oil" class, which includes bitumen, tar sand and oil shale. The enzymatic treatment of the present invention may be used to produce hydrocarbons which have reduced corrosivity, in particular, reduced heavy metal ion content, and reduced inhibition or inactivation of processing catalyst used in the recovery of liquid hydrocarbons, such as, heavy oil. In an embodiment, the enzymatic treatment removes heavy metals from petroporphyrin-rich fractions and asphaltenes of the hydrocarbon staring material.

As used herein, "non-heme haloperoxidase", refers to a haloperoxidase that lacks a heme prosthetic group and catalyzes the halogenation of a variety of substrates in the presence of halide ions and hydrogen peroxide. As used herein, "non-heme haloperoxidase" refers to a non-heme haloperoxidase that may be further classified as chloroperoxidase (E. C. 1.1 1.1.10), bromoperoxidase (EC 1.1 1.1.7), and iodoperoxidase (E. C. 1.1 1.1.8), and that catalyzes the halogenation of a variety of substrates in the presence of hydrogen peroxide. A catalytic triad (serine 97:aspartic acid 229:histidine 258) has been reported to be responsible for the halogenation activity in some members of the non-heme haloperoxidase family (Pelletier et al., Biochimica et Biophysica Acta 1250:149-157 (1995)).

Non-heme haloperoxidases are known in the art and may be obtained from any suitable source, including, e.g., plants, algae, lichen, fungi and bacteria. In one aspect, the non-heme haloperoxidase is derived or isolated from a prokaryotic organism. In another aspect, the non- heme haloperoxidase is derived or isolated from a bacterium. In another aspect, the non-heme haloperoxidase is derived or isolated from an organism selected from the genera consisting of Pseudomonas sp and Agrobacteήum sp. In a further aspect, the source of the non-heme haloperoxidase is selected from the group consisting of Pseudomonas putida and Agrobacteήum tumefaciens.

As used herein, a "vanadium haloperoxidase" (i.e., a vanadium or vanadate containing haloperoxidase) is a haloperoxidase which binds a vanadate ion as a prosethetic group. Vandium haloperoxidases are known in the art and may be obtained from any suitable sources, including, e.g., plants, algae, lichen, fungi and bacteria. Examples of vanadium haloperoxidases include the vanadium haloperoxidase obtained from Curvulaήa sp., e.g., Curvulaήa verruculosa and Curvularia inaequalis, such as C. inaequalis CBS 102.42 as described in WO 95/27046, e.g. a vanadium haloperoxidase encoded by the DNA sequence of WO 95/27046, or C. verruculosa CBS 147.63 or C. verruculosa CBS 444.70 as described in WO 97/04102. Other examples of vanadium haloperoxidase include the vanadium haloperoxidases described in US Patent Nos. 6,410,292, 6,372,465, 6,998,257. A vanadium chloroperoxidase, for example, may be obtained from Drechslera hartlebii as described in WO 01/79459, Dendiyphiella sauna as described in WO 01/79458, Phaeotrichoconis crotalarie as described in WO 01/79461 , or Geniculosporium sp. as described in WO 01/79460. In a preferred embodiment, the vanadium haloperoxidase is the vanadium haloperoxidase obtained from C. verruculosa.

Any suitable hydrocarbon starting material may be treated according to the present invention. Examples of hydrocarbon starting materials, include, e.g., heavy oils. Heavy oil (including extra heavy oil) is generally crude oil which does not flow easily. Heavy oil includes any liquid petroleum with an API gravity of less than about 22°, more preferably an API gravity of less than about 20°. The hydrocarbon starting material may be high asphaltene crude, such as, Venezuelan heavy crude from the Orinoco Belt, crude from Baxterville oilfield in Mississippi on the US Gulf Coast, bitumen, oil sands, tar sands (as found, e.g., in the Athabasca region of Alberta, Canada), oil shale, or processed refinery oil streams, such as vacuum distillation residue and oil processed in the desalting unit. The hydrocarbon starting material also includes fractionated materials from a hydrocarbon starting material.

In a preferred embodiment, the present invention is directed to a method for upgrading heavy oil by treating the heavy oil (or fraction thereof) with a non-heme containing haloperoxidase and hydrogen peroxide, and recovering liquid hydrocarbon. In another preferred embodiment, the present invention is directed to a method for upgrading heavy oil by treating the heavy oil (or fraction thereof) with vanadium haloperoxidase and hydrogen peroxide, and recovering liquid hydrocarbon. The enzymatic treatment of the present invention may preferably be applied to a hydrocarbon starting material which contains asphaltene and liquid hydrocarbon, particularly, hydrocarbon materials with a high viscosity and/or a high metal ion content, e.g., a high metal ion content resulting from the a high content of asphaltenes. Examples of metal ions include, e.g., nickel, molybdenum, and vanadium. It is believed that the enzymatic treatment releases the metal ion from the petroporphyrins present in the hydrocarbon staring material (e.g., asphaltene). In an embodiment, the enzymatic treatment of the invention is applied to a hydrocarbon staring material having a high heavy metal ion content. As used herein "heavy metal" ions include transition metals, metalloids, lanthanides and actinides. The enzymatic treatment may be used to reduce the heavy metal content. In an embodiment, the hydrocarbon staring material is an asphaltene containing material. In another embodiment, the hydrocarbon staring material is a hydrocarbon material which has a high metal ion content, e.g., a high metal ion content resulting from a high content of asphaltenes.

The enzymes are applied as an aqueous phase to the hydrocarbon starting material or to an aqueous phase in contact with the hydrocarbon staring material. The enzymes are applied, e.g., in amounts effective to promote the recovery of hydrocarbon materials (heavy oil), e.g., by reducing he corrosivity of the heavy oil (e.g., metal ion content). The enzyme treatment may be carried out at any suitable process step. Multiple enzyme treatments may be performed to obtain the best result. Hydrogen peroxide is used in combination with the enzyme treatment as haloperoxidases are enzymes which catalyze the oxidation of a halide in the presence of hydrogen peroxide. Hydrogen peroxide employed in the present invention may be present in the starting material or aqueous phase or may added to the starting material or aqueous phase for use in combination with the haloperoxidase treatment. The source of hydrogen peroxide may be hydrogen peroxide or a hydrogen peroxide precursor for in situ production of hydrogen peroxide. Any compound which liberates upon dissolution a peroxide which is useable by haloperoxidase can serve as the source of hydrogen peroxide. Compounds which yield hydrogen peroxide upon dissolution in water or an appropriate aqueous based medium include but are not limited to metal peroxides, percarbonates, persulphates, perphosphates, peroxyacids, alkyperoxides, acylperoxides, peroxyesters, urea peroxide, perborates and peroxycarboxylic acids or salts thereof. Any compound which generates a peroxide that haloperoxidase can use to oxidize is an acceptable source of hydrogen peroxide; this includes a large number of compounds as one skilled in the art will recognize. Mixtures of two or more of these substances can also be used.

Another source of hydrogen peroxide is a hydrogen peroxide generating enzyme system, such as an oxidase together with a substrate for the oxidase. Examples of combinations of oxidase and substrate comprise, but are not limited to, amino acid oxidase (see e.g. U.S. Pat. No. 6,248,575) and a suitable amino acid, glucose oxidase (see e.g. WO 95/29996) and glucose, lactate oxidase and lactate, galactose oxidase (see e.g. WO 00/50606) and galactose, and aldose oxidase (see e.g. WO 99/31990) and a suitable aldose.

In an embodiment, the invention provides a process of recovering a liquid hydrocarbon comprising mixing a hydrocarbon staring material with water or steam to form a slurry, contacting the slurry with a haloperoxidase (non-heme containing haloperoxidase or vanadium haloperoxidase) and hydrogen peroxide, and recovering the liquid hydrocarbon. In a preferred embodiment, the hydrocarbon starting material is mixed with water or steam to form a slurry, e.g. at a temperature of 20-60°C, particularly 30-50°C. The ratio of water to starting material dry matter may generally be in the range 0.001 :1 to 10:1. The enzyme treatment may also be done at a water content which is already found in the existing process. For example, oil sands (tar sands) may be treated at a ratio of 1 :4 to 4:1 , particularly 1 :2 to 2:1 , and refinery oil streams may be treated at a ratio of water to starting material in the range 0.001 :1 to 0.03:1. The haloperoxidase and hydrogen peroxide are incubated with the fossil fuel starting material for an amount of time sufficient to obtain the desired effect, e.g., removal of metal ion. Conveniently, this may occur during pipeline transportation of the slurry (hydrotransport) from the ore preparation to the extractiuon plant. The incubation may be done at a temperature of 20-60°C, particularly 30-50°C. The incubation may last 10 minutes to 48 hours, particularly 1-6 hours. The liquid hydrocarbon material is recovered by separating the liquid hydrocarbon material from the aqueous phase using techniques known in the art.

A solvent or miscibility agent may also be used to promote the processing of the hydrocarbon staring material, e.g., the conversion of the hydrocarbon staring material into liquid heavy oil. Examples of solvents include, e.g., straight chain hydrocarbons (e.g., butane, pentane, hexane, heptane and octane), aromatic solvents (e.g., benzene, toluene, xylene) and chlorinated hydrocarbons. Other examples of solvents include naphtha, gasoil, natural gas distillate. Suitable miscibility agents include citric acid, formic acid, alkyl esters, dialkyl esters, alcohols (e.g., methanol and ethanol). Combinations of the solvents and miscibility agents may also be used. Methods for treating fossil fuel starting materials with solvents are well known in the art and are described, e.g., in U. S: Patent Application 20080060257 and US Patent No. 5,876,592. EXAMPLES

Example 1

An experiment was conducted to quantify the release of metals from vanadium ocatethylporphine (VOEP) present in asphaltenes dissolved in toluene, using vanadium haloperoxidase at pH 3.75 with potassium chloride. The experiment was conducted with and without hydrogen peroxide and with multiple additions as summarized in the table below. Suitable controls were also performed, as summarized in the table below.

Spectral analysis of a solution asphaltene dissolved in toluene showed a small Soret peak at 407 nm. VOEP was dissolved in toluene and treated with vanadium haloperoxidase (vanadium haloperoxidase enzyme available from Novozymes (50 mg/ml) diluted 1 :10 to make it easier to dispense, and 100 μl of the diluted stock was added per 4 ml reaction.) and 7.5 mM H2O2 in 0.1 M phosphate buffer plus KCL (pH 3.75) and incubated at room temperature. Tests were conducted in duplicate. The theoretical maximum release of vanadium to the aqueous phase is 3.62 μg/ml (ppm), based only on the contribution of the vanadium ocatethylporphine (VOEP) substrate. Spectrophotometry of the toluene phase showed loss of the Soret peak at 407 nm and production of a new peak (green color) at about 448 nm.

Vanadium haloperoxidase additions of 2X and 3X were done at 1 hour intervals, and further reduced the green coloration and intensity of the 448 nm peak. Total reaction volumes in different treatments were kept parallel by adding distilled water instead of enzyme solution and H2O2.

As shown in the table below, it is clear that the vanadium haloperoxidase is able to release up to 60% of the vanadium present in vanadium ocatethylporphin (2.18 ppm vs. 3.62 pm), given multiple enzyme additions and H2O2 additions.

Claims

1. A process of recovering hydrocarbons, comprising contacting a hydrocarbon starting material comprising liquid hydrocarbon with a non-heme haloperoxidase and hydrogen peroxide, and recovering liquid hydrocarbon.

2. The process of claim 1 , wherein the process comprises: a) providing a hydrocarbon starting material comprising liquid hydrocarbon, b) preparing a slurry comprising the starting material, water, non-heme haloperoxidase and hydrogen peroxide, c) incubating the slurry, and d) recovering liquid hydrocarbon.

3. The process of claim 1 , wherein the non-heme haloperoxidase is a chloroperoxidase.

4. The process of claim 1 , wherein the non-heme haloperoxidase is a bromoperoxidase.

5. The process of claim 1 , wherein the non-heme haloperoxidase is an iodoperoxidase.

6. The process of claim 1 , wherein the hydrocarbon staring material is heavy oil.

7. The process of claim 1 , wherein the hydrocarbon staring material is asphaltene crude.

8. The process of claim 1 , wherein the hydrocarbon stating material is bitumen, oil sands or tar sands.

9. A process of recovering hydrocarbons, comprising contacting a hydrocarbon starting material comprising liquid hydrocarbon with a vanadium haloperoxidase and hydrogen peroxide, and recovering liquid hydrocarbon.

10. The process of claim 9, wherein the process comprises: a) providing a starting material comprising liquid hydrocarbon, b) preparing a slurry comprising the starting material, water, vanadium haloperoxidase and hydrogen peroxide, c) incubating the slurry, and d) recovering liquid hydrocarbon.

1 1. The process of claim 9, wherein the vanadium haloperoxidase is obtained from Curvularia sp.

12. The process of claim 9, where the vanadium haloperoxidase is obtained from Curvularia verruculosa or Curvularia inaequalis,

13. The process of claim 9, wherein the vanadium haloperoxidase is obtained from Drechslera hartlebii, Dendiyphiella sauna, Phaeotrichoconis crotalaria, Geniculosporium sp. Drechslera hartlebii, or Dendryphiella salina.

14. The process of claim 9, wherein the hydrocarbon staring material is heavy oil.

15. The process of claim 9, wherein the hydrocarbon staring material is asphaltene crude.

16. The process of claim 9, wherein the hydrocarbon stating material is bitumen, oil sands or tar sands.

17. A process of recovering hydrocarbons, comprising:

a) providing a hydrocarbon starting material comprising petroporphyrin-rich fractions or asphaltene and liquid hydrocarbon;

b) preparing a slurry comprising the starting material, water, a non-heme haloperoxidase and hydrogen peroxide,

c) incubating the slurry,

d) recovering the liquid hydrocarbon.

18. A process of recovering hydrocarbons, comprising:

a) providing a hydrocarbon starting material comprising petroporphyrin-rich fractions or asphaltene and liquid hydrocarbon; b) preparing a slurry comprising the starting material, water, a vanadium haloperoxidase and hydrogen peroxide, c) incubating the slurry, d) recovering the liquid hydrocarbon.