CA2642375A1 - Process for extracting hydrocarbons from oil sand - Google Patents

Abstract

A process for extracting hydrocarbons from oil sand, in which the oil sand is treated in a separation apparatus in at least one process step with a composition which comprises water and a hydrophobin and if appropriate further assistants, leads to an improved yield of hydrocarbons.

Description

y Process for extracting hydrocarbons from oil sand The present invention relates to a process for extracting hydrocarbons from oil sand.

Oil sand occurs in many places on earth, for example in deposits in Venezuela and Canada. The oil sand consists essentially of a mixture of different hydrocarbons (for example low molecular weight, cyclic and open-chain, and especially also bitumen), sand and other minerals, and also water. The organic component of oil sand consists frequently of different hydrocarbons which feature a high viscosity at room temperature and which function as binders to the other components of the oil sand.

The typical mineral components in oil sand are sand, clay and particles of various rocks. These mineral components may consist of particles of different particle size according to the origin.
The water component of oil sand consists essentially of an aqueous film which surrounds the sand grains or the mineral components. A typical oil sand comprises, for example, from 8 to 22% by weight of hydrocarbons and from about 3 to 6% by weight of water, and also sand and other mineral components.. The composition of the oil sand is subject to strong regional variations, and it is also possible for different oil sand deposits to occur at one geographical site, for example depending on the depth of the oil sand deposit.

In the last few years, various processes for extracting the hydrocarbons which serve as energy carriers and as chemical raw materials from the oil sand deposits have been developed. In a conventional hot water process, mixing of the oil sand with hot water with vigorous stirring in a tank at temperatures of from 60 to 95 C generates a multiphase system which is then separated into its phases in a multistage process.

Various processes for treatment of oil sand are described, for example, in US 6,007,708 and US 2007/0090025 A, but the known processes frequently enable only an unsatisfactory yield of hydrocarbons or are technically very complicated and thus expensive. For instance, US 6,007,708 describes a process for extracting bitumen from oil sand, in which the oil sand is admixed with water and treated with an air feed.
A subsequent separation phase is effected in a primary tank, in which a separation into bitumen foam, sand and a mixed phase is effected. Subsequently, the separated B07/0415CA IB/JA/bmUauc/kri October 21, 2008 phases are sent to further processing. US 2007/009 0025 A also discloses a multistage process for extracting bitumen from oil sand. In this process, the bitumen-containing layer is sent to a flotation process after removal.

CA-A 2 276 912 discloses a process for removing bitumen from oil sand, in which a treatment with water and a nonflammable emulsifier is effected. The objective in CA-A 2 276 912 is to accelerate the separation of inorganic phase and oil layer.

WO 2002/074 881, moreover, discloses a process for treatment of compositions with a low oil content, in which the material is treated at high temperatures and application of pressure in a reaction tank using water and a catalyst.

In the processes practiced, for example, in Canadian, Californian or Venezuelan oil sand deposits, the oil sand is first obtained by opencast methods and then transported to an extraction plant, in which an extraction is effected using hot water, pH
regulators and further assistants. Before the extraction step, the oil sand is, if appropriate, conditioned in a mixer. The resulting hydrocarbon slurry is then pumped into an extraction plant, where the input of mechanical energy causes separation into the hydrocarbon component and the mineral component. Frequently, a gas is introduced (for example by blowing in hot air), as a result of which ultrasmall gas bubbles become attached to the hydrocarbon particles or hydrocarbon droplets, which can result in accelerated removal. This flotation process enables an improved yield of hydrocarbons.
In the treatment of oil sand using water, hydrocarbons are found in the upper foam layer (phase A), in the aqueous phase (phase B) and in the (lower) solid phase (phase C).

In a separator, the hydrocarbon component collects to a considerable degree in the foam layer (phase A) (which floats on top). This foam layer can preferably be removed mechanically and comprises generally approx. 60% by weight of hydrocarbons, approx.
30% by weight of water and about 10% by weight of extraneous substances.

This phase A can be treated using centrifuges and/or extraction methods. The remaining residue consists of an aqueous phase (phase B) and a solid phase (phase C), and the two can either be separated, disposed of or used further. Various processes and the corresponding apparatus are described, for example, in US 2007/0131590.

=

In an alternative process for extracting hydrocarbons from oil sand, water can be introduced into an oil sand deposit (especially in underground deposits) in the form of hot steam, which can achieve a separation of the bitumen component from the mineral component.

It is an object of the present invention to provide an improved process for extracting hydrocarbons from oil sand, in which the hydrocarbons can be removed from the remaining components in an energy-saving process which can be carried out in a technically simple manner. At the same time, both an efficient extraction of hydrocarbons from an already extracted oil sand and a separation of hydrocarbons in a deposit (in situ) shall be enabled.

It is a further object of the present invention to provide a process in which the following criteria are substantially fulfilled:

a) the yield of hydrocarbons in phase A can be increased, b) the process step of separation of the organic phase from extraneous substances from aqueous phase B can be accelerated, c) a reduction in the process temperature can be achieved, d) the hydrocarbon content in the solid phase C can be reduced, e) the content of nonhydrocarbons in phase A can be reduced, f) the content of hydrocarbons in the wastewater and/or solid waste can be reduced.
It has now been found that the extraction of hydrocarbons from oil sand can be significantly improved and simplified by the addition of particular amounts of specific proteins during the treatment of the oil sand. The present invention also relates to the use of specific proteins, the so-called hydrophobins, for extracting hydrocarbons from oil sand.

Hydrophobins are small proteins of from about 100 to 150 amino acids, which occur, for example, in filamentous fungi such as Schizophyllum commune. They generally have 8 cysteine units in the molecule. Hydrophobins can be isolated from natural sources, but they can also be obtained by means of recombinant methods, as disclosed, for example, in WO 2006/082 251 or WO 2006/131 564.

The prior art has already proposed the use of hydrophobins for various applications.
For instance, WO 1996/41882 proposes the use of hydrophobins as emulsifiers, thickeners, surfactants, for hydrophilizing hydrophobic surfaces, for improving the water resistance of hydrophilic substrates, and for producing oil-in-water emulsions or water-in-oil emulsions.

Additionally proposed are pharmaceutical applications such as the production of ointments and cosmetic applications or the production of shampoos. EP-A 1 252 discloses the coating of various substrates with a solution comprising hydrophobins at a temperature of from 30 to 80 C. Also already proposed has been, for example, the use of hydrophobins as a demulsifier (see WO 2006/103251), as an evaporation retardant (see WO 2006/128877) or soiling inhibitor (see WO 2006/103215).

In the context of the present invention, the term "hydrophobins" should be understood hereinafter to mean polypeptides of the general structural formula (I) Xn-C'-X1-50-C2-XO-5-C3-X1-100-C4-X1-100-C5-X1-50-C6-XO-5-C7-X1-50-C8-Xm (I) where X may be any of the 20 naturally occurring amino acids (Phe, Leu, Ser, Tyr, Cys, Trp, Pro, His, Gin, Arg, Ile, Met, Thr, Asn, Lys, Val, Ala, Asp, Glu, Gly). In the formula, the X radicals may be the same or different in each case. The indices beside X
are each the number of amino acids in the particular part-sequence X, C is cysteine, alanine, serine, glycine, methionine or threonine, where at least four of the residues designated with C are cysteine, and the indices n and m are each independently natural numbers between 0 and 500, preferably between 15 and 300.

The polypeptides of the formula (I) are also characterized by the property that, at room temperature, after coating a glass surface, they bring about an increase in the contact angle of a water droplet of at least 20 , preferably at least 25 and more preferably 30 , compared in each case with the contact angle of an equally large water droplet with the uncoated glass surface.

The amino acids designated with C' to C8 are preferably cysteines. However, they may also be replaced by other amino acids with similar space-filling, preferably by alanine, serine, threonine, methionine or glycine. However, at least four, preferably at least 5, more preferably at least 6 and in particular at least 7 of positions C' to C8 should consist of cysteines. In the inventive proteins, cysteines may either be present in reduced form or form disulfide bridges with one another. Particular preference is given to the intramolecular formation of C-C bridges, especially that with at least one intramolecular disulfide bridge, preferably 2, more preferably 3 and most preferably 4 intramolecular disulfide bridges. In the case of the above-described exchange of cysteines for amino acids with similar space-filling, such C positions are advantageously exchanged in pairs which can form intramolecular disulfide bridges 5 with one another.

If cysteines, serines, alanines, glycines, methionines or threonines are also used in the positions designated with X, the numbering of the individual C positions in the general formulae can change correspondingly.
Preference is given to using hydrophobins of the general formula (II) Xn-C1-X3-25-C2-X0-2-C3-X5-50-C4-X2-35-C5-X2-15-C6-X0-2'C7-X3-35-CB-Xm (II) to perform the present invention, where X, C and the indices beside X and C
are each as defined above, the indices n and m are each numbers between 0 and 350, preferably from 15 to 300, and the proteins additionally feature the above-illustrated change in contact angle, and, furthermore, at least 6 of the residues designated with C
are cysteine. More preferably, all C residues are cysteine.
Particular preference is given to using hydrophobins of the general formula (III) Xn-C1-X5-9'C2-C3-X11-39-C4-X2-23-C5-X5-9'CB-C'-X6-18-C8-Xm (I11) where X, C and the indices beside X are each as defined above, the indices n and m are each numbers between 0 and 200, and the proteins additionally feature the above-illustrated change in contact angle, and at least 6 of the residues designated with C are cysteine. More preferably, all C residues are cysteine.

The Xn and XR, residues may be peptide sequences which naturally are also joined to a hydrophobin. However, one residue or both residues may also be peptide sequences which are naturally not joined to a hydrophobin. This is also understood to mean those Xn and/or Xm residues in which a peptide sequence which occurs naturally in a hydrophobin is lengthened by a peptide sequence which does not occur naturally in a hydrophobin.

r If X, and/or Xm are peptide sequences which are not naturally bonded to hydrophobins, such sequences are generally at least 20, preferably at least 35 amino acids in length.
They may, for example, be sequences of from 20 to 500, preferably from 30 to 400 and more preferably from 35 to 100 amino acids. Such a residue which is not joined naturally to a hydrophobin will also be referred to hereinafter as a fusion partner.
This is intended to express that the proteins may consist of at least one hydrophobin moiety and a fusion partner moiety which do not occur together in this form in nature.
Fusion hydrophobins composed of fusion partner and hydrophobin moiety are described, for example, in WO 2006/082251, WO 2006/082253 and WO 2006/131564.
The fusion partner moiety may be selected from a multitude of proteins. It is possible for only one single fusion partner to be bonded to the hydrophobin moiety, or it is also possible for a plurality of fusion partners to be joined to one hydrophobin moiety, for example on the amino terminus (Xn) and on the carboxyl terminus (Xm) of the hydrophobin moiety. However, it is also possible, for example, for two fusion partners to be joined to one position (X, or Xm) of the inventive protein.

Particularly suitable fusion partners are proteins which naturally occur in microorganisms, especially in Escherischia coli or Bacillus subtilis. Examples of such fusion partners are the sequences yaad (SEQ ID NO: 16 in WO 2006/082251), yaae (SEQ ID NO: 18 in WO 2006/082251), ubiquitin and thioredoxin. Also very suitable are fragments or derivatives of these sequences which comprise only some, for example from 70 to 99%, preferentially from 5 to 50% and more preferably from 10 to 40% of the sequences mentioned, or in which individual amino acids or nucleotides have been changed compared to the sequence mentioned, in which case the percentages are each based on the number of amino acids.

In a further preferred embodiment, the fusion hydrophobin, as well as the fusion partner mentioned as one of the Xn or Xm groups or as a terminal constituent of such a group, also has a so-called affinity domain (affinity tag / affinity tail). In a manner known in principle, this comprises anchor groups which can interact with particular complementary groups and can serve for easier workup and purification of the proteins.
Examples of such affinity domains comprise (His)k, (Arg)k, (Asp)k, (Phe)k or (Cys)k groups, where k is generally a natural number from 1 to 10. It may preferably be a (His)k group, where k is from 4 to 6.

In this case, the Xn and/or XR, group may consist exclusively of such an affinity domain, or else an Xn or Xm radical which is or is not naturally bonded to a hydrophobin is extended by a terminal affinity domain.

~

The hydrophobins used in accordance with the invention may also be modified in their polypeptide sequence, for example by glycosylation, acetylation or else by chemical crosslinking, for example with glutaraidehyde.

One property of the hydrophobins or derivatives thereof used in accordance with the invention is the change in surface properties when the surfaces are coated with the proteins. The change in the surface properties can be determined experimentally, for example, by measuring the contact angle of a water droplet before and after the coating of the surface with the protein and determining the difference of the two measurements.

The performance of contact angle measurements is known in principle to those skilled in the art. The measurements are based on room temperature and water droplets of 5 l and the use of glass plates as substrate. The exact experimental conditions for an example of a suitable method for measuring the contact angle are given in the experimental section. Under the conditions mentioned there, the fusion proteins used in accordance with the invention have the property of increasing the contact angle by at least 20 , preferably at least 25 , more preferably at least 30 , compared in each case with the contact angle of an equally large water droplet with the uncoated glass surface.

Particularly preferred hydrophobins for performing the present invention are the hydrophobins of the dewA, rodA, hypA, hypB, sc3, basfl, basf2 type. These hydrophobins including their sequences are disclosed, for example, in WO

251. Unless stated otherwise, the sequences specified below are based on the sequences disclosed in WO 2006/082 251. An overview table with the SEQ ID
numbers can be found in WO 2006/082 251 on page 20.

Especially suitable in accordance with the invention are the fusion proteins yaad-Xa-dewA-his (SEQ ID NO: 20), yaad-Xa-rodA-his (SEQ ID NO: 22) or yaad-Xa-basfl-his (SEQ ID NO: 24), with the polypeptide sequences specified in brackets and the nucleic acid sequences which code therefor, especially the sequences according to SEQ
ID
NO: 19, 21, 23. More preferably, yaad-Xa-dewA-his (SEQ ID NO:20) can be used.

Proteins which, proceeding from the polypeptide sequences shown in SEQ ID NO.
20, 22 or 24, arise through exchange, insertion or deletion of from at least one up to 10, preferably 5 amino acids, more preferably 5% of all amino acids, and which still have the biological property of the starting proteins to an extent of at least 50%, are also particularly preferred embodiments. A biological property of the proteins is understood here to mean the change in the contact angle by at least 20 , which has already been =

described.

Derivatives particularly suitable for performing the present invention are derivatives derived from yaad-Xa-dewA-his (SEQ ID NO: 20), yaad-Xa-rodA-his (SEQ ID NO:
22) or yaad-Xa-basfl-his (SEQ ID NO: 24) by truncating the yaad fusion partner.
Instead of the complete yaad fusion partner (SEQ ID NO: 16) with 294 amino acids, it may be advantageous to use a truncated yaad residue. The truncated residue should, though, comprise at least 20, preferably at least 35 amino acids. For example, a truncated radical having from 20 to 293, preferably from 25 to 250, more preferably from 35 to 150 and, for example, from 35 to 100 amino acids may be used. One example of such a protein is yaad40-Xa-dewA-his (SEQ ID NO: 26 in PCT/EP2006/064720), which has a yaad residue truncated to 40 amino acids.

A cleavage site between the hydrophobin and the fusion partner or the fusion partners can be utilized to split off the fusion partner and to release the pure hydrophobin in underivatized form (for example by BrCN cleavage at methionine, factor Xa cleavage, enterokinase cleavage, thrombin cleavage, TEV cleavage, etc.).

The hydrophobins used in accordance with the invention for treatment of oil sand can be prepared chemically by known methods of peptide synthesis, for example by Merrifield solid-phase synthesis.

Naturally occurring hydrophobins can be isolated from natural sources by means of suitable methods. Reference is made by way of example to Wosten et al., Eur. J
Cell Bio. 63, 122-129 (1994) or WO 1996/41882. A recombinant production process for hydrophobins without fusion partners from Talaromyces thermophilus is described by US 2006/0040349.

Fusion proteins can be prepared preferably by genetic engineering methods, in which one nucleic acid sequence, especially DNA sequence, encoding the fusion partner and one encoding the hydrophobin moiety are combined in such a way that the desired protein is generated in a host organism as a result of gene expression of the combined nucleic acid sequence. Such a preparation process is disclosed, for example, by WO
2006/082251 or WO 2006/082253. The fusion partners considerably ease the production of the hydrophobins. Fusion hydrophobins are produced with significantly better yields in the recombinant processes than hydrophobins without fusion partners.
The fusion hydrophobins produced by the host organisms by the recombinant process can be worked up in a manner known in principle and can be purified by means of r known chromatographic methods.

In a preferred embodiment, the simplified workup and purification process disclosed in WO 2006/082253, pages 11/12, can be used.
In this process, the fermented cells are first removed from the fermentation broth and disrupted, and the cell fragments are separated from the inclusion bodies. The latter can advantageously be done by centrifugation. Finally, the inclusion bodies can be disrupted in a manner known in principle, for example by means of acids, bases and/or detergents, in order to release the fusion hydrophobins. The inclusion bodies comprising the fusion hydrophobins used in accordance with the invention can generally be dissolved fully even using 0.1 M NaOH within approx. 1 h.

The resulting solutions can - if appropriate after establishing the desired pH
- be used without further purification to perform this invention. However, the fusion hydrophobins can also be isolated as a solid from the solutions. The isolation can preferably be effected by means of spray granulation or . spray drying, as described in WO 2006/082253, page 12. The products obtained by the simplified workup and purification process comprise, as well as residues of cell fragments, generally from approx. 80 to 90% by weight of proteins. The amount of fusion hydrophobins is, according to the fusion construct and fermentation conditions, generally from 30 to 80%
by weight based on the amount of all proteins.

The isolated products comprising fusion hydrophobins can be stored as solids and be dissolved in the media desired in each casefor use.
The fusion hydrophobins can be used to perform this invention as such or else, after eliminating and removing the fusion partner, as "pure" hydrophobins. A
splitting is advantageously undertaken after the isolation of the inclusion bodies and their dissolution.
The present invention relates to a process for extracting hydrocarbons from oil sand, in which the oil sand is treated in a separation apparatus in at least one process step with a composition which comprises a hydrophobin derivative. If appropriate the composition which comprises a hydrophobin derivative may comprises further assistants.

Preferably, the hydrophobin derivative is used together with water and the amount of hydrophobin derivative, based on the overall composition composed of oil sand, water and additives, is from 0.1 to 1000 ppm. In particular, the used hydrophobin derivative is a fusion hydrophobin or a derivative thereof.

5 In a preferred embodiment, in the process for extracting hydrocarbons from oil sand an aqueous composition which comprises, as well as the hydrophobin derivative, at least one further compound which improves the phase separation of water and hydrocarbon phase is used.

10 More preferred, the used hydrophobin derivative is a fusion hydrophobin selected from the group of yaad-Xa-dewA-his (SEQ ID NO: 20), yaad-Xa-rodA-his (SEQ ID NO:
22) or yaad-Xa-basfl-his (SEQ ID NO: 24), were yaad may also be a truncated yaad' fusion partner having from 20 to 293 amino acids.

In a further preferred embodiment, the invention relates to a extracting process as described above wherein an oil sand which comprises from 5 to 25% by weight of hydrocarbons, from 3 to 8% by weight of water and from 70 to 95% by weight of inorganic components is mixed thoroughly with an aqueous composition which comprises from 10 to 80% by weight of water and from 1 to 1000 ppm of hydrophobin derivative at a temperature of from 15 to 95 C, and, after a separation phase, a removal of the hydrocarbon-containing phases and further purification steps of these hydrocarbon-containing phases are effected. If appropriated in the process mentioned above for extracting hydrocarbons from oil sand, an oil sand is comminuted and prepurified before mixed thoroughly with an aqueous composition.
Furthermore, the present invention is directed to the use of a composition comprising at least one hydrophobin derivative for extracting hydrocarbons from oil sand, wherein the hydrophobin derivative is particularly used in the mixing of oil sand with an aqueous phase.
Preferably, the invention is directed to the use of a composition comprising at least one hydrophobin derivative for extracting hydrocarbons from oil sand, wherein the hydrophobin derivative is used in an amount of from 0.1 to 1000 ppm based on the overall composition, more preferred in an amount of from 10 to 150 ppm based on the overall composition.

In the process according to the invention for extracting hydrocarbons from oil sand, in ~

which the oil sand is treated with an aqueous composition which comprises a hydrophobin, it is possible, for example, to carry out a process sequence shown in the flow diagram in Figure 1.

In Figure 1, the oil sand (OS) is first transported from an oil sand deposit (1) into an extraction plant (2).

Raw water (RW) is fed into the extraction plant (2) from a raw water tank (5).
In the extraction plant (2), the oil sand is mixed thoroughly with the raw water. The additives (AD) - for example the hydrophobin and/or other additives - can be introduced separately into the extraction plant (2), but they can also be introduced together with the raw water introduction (RWI).

In the flow diagram shown in Figure 1, the wastes (R) of the extraction process are removed from the extraction plant (2). In addition, the bitumen foam (BF) is removed and sent to a further processing unit (3), in which foam processing and solvent recovery takes place. The waste layer (TS) is withdrawn from the extraction plant (2) and passes into a collecting tank (6), in which a splitting into recoverable water (RW) and recovered bitumen (RB) can take place. The recovered water (RW) can be fed into the water reservoir vessel (5); the recovered bitumen (RB) can be recycled into the extraction plant (2).

The composition (B) obtained from the bitumen foam (BF) in the plant (3), which comprises a high proportion of hydrocarbons, is, if appropriate, sent to a further reprocessing step in a plant (4). In this case, the composition can also be heated and subjected to further wash processes. The hydrocarbon-rich compositions (RF) obtained can then be sent to a refinery. For the performance of the bitumen foam treatment in the process unit (3), the additional introduction of a solvent (S) may be advisable.

The waste products of the bitumen processing step obtained in the processing unit (3) include water, inorganic solids, asphalt, solvents and small amounts of bitumen. These waste products (T) can, if appropriate, be finally stored.

To illustrate the process according to the invention for extracting hydrocarbons from oil sand, a more precise flow diagram for the hydrocarbon extraction is shown in Figure 2.
Starting from an oil sand slurry (CS), which can be pumped, for example, through a pipeline to the plant, it is fed into the primary separation unit (PSC). This separation ~

unit (10) serves for the first splitting of the oil sand slurry fed in. The hydrocarbon-containing foam (PSCF) obtained in a first step using water and hydrophobin is removed and fed to a further separation unit (12), into which, for example, steam or air can be fed. From this separation unit (12), the hydrocarbon-containing foam can be passed on into a processing unit (14) in which foam treatment is effected.

In the primary separation unit (10), a middle layer (M) (mixed phase) is also obtained, which can be sent to a flotation process in a flotation plant (16). From this flotation plant (16), a hydrocarbon-containing slurry can be recycled back into the primary separation unit (10). The wastes of the flotation process (PFT) can be sent to a secondary flotation process in a further flotation plant (18). The wastes of the flotation processes can undergo splitting into solid wastes (26) which can be disposed of by landfill (such as slightly contaminated sand) and water (W), which can either be disposed of or preferably recycled into the process.
In the treatment of the flotation wastes, a more rapid and improved separation into solid wastes and liquid constituents can be effected in the plant, for example, as a result of addition of thickeners from a reservoir vessel (22). The foam (F) obtained in the flotation steps can be recycled into the primary separation process in the plant (10).
The examples which follow are intended to illustrate the invention in detail:
Example 1 Provision and testing of the hydrophobins For the examples, one fusion hydrophobin with the complete yaad fusion partner (yaad-Xa-dewA-his; referred to hereinafter as hydrophobin A) and one fusion hydrophobin with a yaad40-Xa-dewA-his (hydrophobin B) fusion partner truncated to 40 amino acids were used. The hydrophobins were prepared by the procedure described in WO 2006/082253. The products were worked up by the simplified purification process according to Example 9 of WO 2006/82253 and spray-dried according to Example 10. The total protein content of the resulting dried products was in each case from approx. 70 to 95%by weight; the content of hydrophobins was from approx. 40 to 90% by weight based on the total protein content. The products were used as such for the experiments.

Performance testing of the hydrophobins:

Characterization of the fusion hydrophobins by contact angle variation of a water droplet on glass (window glass, Suddeutsche Glas, Mannheim):
For the tests, the spray-dried products comprising fusion hydrophobins were dissolved in water with addition of 50 mM sodium acetate pH 4 and 0.1 % by weight of polyoxyethylene(20) sorbitan monolaurate (Tween 20). The concentration of the product was 100 g/ml in aqueous solution.
Procedure:
- Incubation of glass platelets overnight (temperature 80 C), then wash coating in distilled water, - then incubation 10 min/80 C/1 % sodium dodecylsulfate (SDS) solution in dist.
water, - washing in dist. water.

The samples are dried under air and the contact angle (in degrees) of a droplet of 5 pl of water at room temperature is determined. The contact angle measurement was determined on a dataphysics contact angle system OCA 15+, Software SCA 20.2Ø
(November 2002). The measurement was effected according to the manufacturer's instructions.

Untreated glass gave a contact angle of from 15 to 30 5 . Coating with the fusion hydrophobin yaad-Xa-dewA-his6 gave a contact angle increase of more than 30 ;
coating with the fusion hydrophobin yaad40-Xa-dewA-his likewise gave a contact angle increase of more than 30 .

Example 2 Analysis of the oil sand The oil sand analyzed here consists of the following components:
- 8 to 22% by weight of hydrocarbons (bitumen) - approx. 5% water - from 75 to 90% sand (mainly quartz, approx. 10% clay as fines < 44 m).

The analysis results obtained were in particular:

a) solids content: 96.9% (by means of IR drying) b) extractable organic substances: from 120 to 130 g/kg (Soxhlet extraction), c) C10 to C40 hydrocarbon content (boiling range from 175 to 525 C): 35 g/kg, d) sum of all polyaromatics: 9.9 g/kg, e) sum of nonalkylated polyaromatic hydrocarbons: 22 mg/kg.

For the measurement of the particle size distribution, a separation of oil sand using hexane as the solvent was carried out. 10 g of oil sand were mixed with approx. 70 ml of hexane, and the bitumen fractions were leached out.

For the particle size distribution, see the table which follows.
Size Volume 10-6m below %
0.265 0.00 0.337 0.02 0.427 0.13 0.542 0.39 0.688 0.88 0.874 1.71 1.11 2.96 1.41 4.63 1.79 6.71 2.27 9.08 2.88 11.60 3.65 14.14 4.64 16.67 5.88 19.22 7.47 21.79 9.48 24.35 12.03 26.92 15.27 29.50 19.38 32.11 25.00 34.88 31.22 37.27 39.62 39.98 50.28 43.21 63.82 47.60 81.00 53.90 102.8 62.70 130.5 73.98 165.6 85.37 210.2 94.15 266.8 99.06 338.6 100.0 The distribution of the particle sizes is broad between 0.5 and 300 m. The mean particle diameter is at d50 = 70 m. The removal of the sand from the organic component (bitumen) is associated with a relatively high level of cost inconvenience 5 especially for the finer particles. The sand particles at approx. 100 pm can be removed by centrifugation.

Example 3 Exploratory, noninventive laboratory test for bitumen extraction 10 Beaker tests are carried out, initially without the flotation which is customary in the industrial standard process but is difficult in the laboratory (foam formation of the bitumen as a result of air and energy introduction). However, comparable flotation tests using hydrophobin can also be carried out without technical difficulties. The exploratory tests are used to provide the comparative basis for the visual assessment of the 15 inventive bitumen extraction in Example 4.

In the beaker test, the oil sand is admixed with water in a mass ratio of 8:10 and with different amounts of NaOH (setting of the pH from 7 to 11) for pH regulation.
Settling tests are carried out at temperatures of 40, 60, 80 C with 30 minutes of stirring time and 30 minutes of settling time.

The stirrer speed is selected at about 500 revolutions per minute such that complete dispersion is achieved, i.e. such that no lasting coherent areas of one phase can form on the surface. The stirring is associated with minor introduction of air.

After 30 minutes of settling, a characteristic settling profile with (essentially) three layers is formed for all samples, which are shown and illustrated in Figure 3.
Figure 3 shows the test results of the beaker tests in schematic form.
The basis used for the creation of the graphic illustrations was the photographs taken when the tests were performed.

Figure 3 shows three different processes for separating oil sand (V1, V2 and V3; V2 and V3 are explained in Example 4). In the test designated V1, an oil sand treated with water without the addition of hydrophobin is shown. The layer (31) consists of the hydrocarbon-containing liquid bitumen which, owing to the low gas introduction in the course of stirring, comprises only a small amount of foam. The middle layer (32) consists of a complex mixed phase composed of hydrocarbons, sand, further inorganic components and water. The layer (33) consists predominantly of settled contaminated sand. The separation into the three layers takes a long time and is incomplete.
Between layers 32 and 33, there is additionally a very thin layer of bitumen.
The bitumen fraction which settles here is a small portion of the total amount of bitumen and has a density which is greater than that of the aqueous layer (32).

Assessing the quality of the separation is not unproblematic. The depletion of the bitumen from the sand is one factor, but others are the sand/fines content in the aqueous phase and the water content in the bitumen phase. For the tests, the criterion used for the separation quality is the total carbon content in the sand sediment. For the analysis, the sand layer has to be sufficiently dense. This is ensured only after approx.
minutes' settling. The liquid phases are cautiously decanted and then the bitumen 25 layer above the sand is pushed to the side with a spatula. A sample can then be taken from the sediment.

A pH of 11 provides the best depletion from the sand in several tests, which reflects the literature data for the parameters of the currently used oil sand extraction.
An influence 30 of the change in temperature cannot be discerned from these measurements.

Example 4 Tests with addition of hexane without and with hydrophobin For the further tests, the flotation is replaced by the addition of hexane as a solvent for the hydrocarbons. As a result of the use of hexane, a better separation is to be expected than in Example 3, in which only water is used. The addition of sodium hydroxide solution is dispensed with, which in turn leads, if anything, to worsened depletion of the bitumen from the sand.

In the industrial standard extraction process, a hydrocarbon is used only after the flotation and centrifugal removal of solids.
Test parameters of beaker tests with hexane and hydrophobin:
- beaker: volume approx. 200 ml - volume ratio of sand:water:hexane = 50 ml:100 ml:50 ml, - mass ratio of 59 g:93 g:33 g - stirrer bar speed 750 revolutions per minute - initial stirring time 15 minutes, then stir again for 5 minutes in each case after the addition of the hydrophobin - hydrophobin addition in powder form - hydrophobin from 1 mg/kg to 1000 mg/kg based on total amount, pH = 7 The phase separation is assessed visually. The result is likewise shown in Figure 3.

In the beaker designated V2, the oil sand is used with water and the hexane solvent but without hydrophobin. This gives rise to a bitumen-containing hexane phase (34), a nontransparent complex middle layer (32) comprising hydrocarbons, sand, suspended inorganic substances and water, and a layer of sand as sediment (33). Layer (34) takes up a somewhat greater volume than (31), since hexane is used additionally.
(32) and (33) correspond visually to the layers from Example 3.

In the beaker designated V3, the oil sand is treated with water, hydrophobin being added to the water in an amount of 100 mg of protein per kg of the mixture. In addition, the hexane solvent is added. Even after a short time, a clearly separated triphasic system is obtained. The bitumen-containing hexane phase occurs as phase (34);
as the middle phase (35), a clear aqueous phase which comprises essentially no suspended inorganic substances and no sand is observed. In addition, a sediment phase (33) composed of only slightly contaminated sand is observed.

The sediment phases (33) are identical by visual assessment in all tests.
However, the sediment layer in V3 is lighter than in V1 and V2, which indicates improved bitumen depletion from the sand.

The hydrophobin was also used in lower and higher concentrations than 100 mg/kg.
The results can be summarized as follows:

- the aqueous phase becomes rapidly clear at an added amount of 100 mg/kg.
- an optimum is discernible at 100 mg/kg of hydrophobin.
- at significantly lower and higher concentrations of hydrophobin, the aqueous phase becomes similarly cloudy to that without addition of hydrophobin.
- negative effects through the repeated stirring are ruled out through the addition of hydrophobin compared to a blank test without addition.

Claims (12)

1. A process for extracting hydrocarbons from oil sand, in which the oil sand is treated in a separation apparatus in at least one process step with a composition which comprises a hydrophobin derivative.

2. A process for extracting hydrocarbons from oil sand according to claim 1, in which the oil sand is treated with a composition which comprises further assistants.

3. The process for extracting hydrocarbons from oil sand according to either of claim 1 and 2, wherein the hydrophobin derivative is used together with water and the amount of hydrophobin derivative, based on the overall composition composed of oil sand, water and additives, is from 0.1 to 1000 ppm.

4. The process for extracting hydrocarbons from oil sand according to any of claims 1 to 3, wherein an aqueous composition which comprises, as well as the hydrophobin derivative, at least one further compound which improves the phase separation of water and hydrocarbon phase is used.

5. The process for extracting hydrocarbons from oil sand according to any of claims 1 to 4, wherein the hydrophobin derivative used is a fusion hydrophobin or a derivative thereof.

6. The process for extracting hydrocarbons from oil sand according to any of claims 1 to 5, wherein an oil sand which comprises from 5 to 25% by weight of hydrocarbons, from 3 to 8% by weight of water and from 70 to 95% by weight of inorganic components is mixed thoroughly with an aqueous composition which comprises from to 80% by weight of water and from 1 to 1000 ppm of hydrophobin derivative at a temperature of from 15 to 95°C, and, after a separation phase, a removal of the hydrocarbon-containing phases and further purification steps of these hydrocarbon-containing phases are effected.

7. The process for extracting hydrocarbons from oil sand according to any of claims 1 to 6, wherein an oil sand is comminuted and prepurified before mixed thoroughly with an aqueous composition.

8. The process for extracting hydrocarbons from oil sand according to any of claims 1 to 7, wherein the hydrophobin derivative used is a fusion hydrophobin selected from the group of yaad-Xa-dewA-his (SEQ ID NO: 20), yaad-Xa-rodA-his (SEQ ID NO:
22) or yaad-Xa-basf1-his (SEQ ID NO: 24), where yaad may also be a truncated yaad' fusion partner having from 20 to 293 amino acids.

9. The use of a composition comprising at least one hydrophobin derivative for extracting hydrocarbons from oil sand.

10. The use of a composition according to claim 9, wherein the hydrophobin derivative is used in the mixing of oil sand with an aqueous phase.

11. The use according to either of claims 9 and 10, wherein the hydrophobin derivative is used in an amount of from 0.1 to 1000 ppm based on the overall composition.

12. The use according to any of claims 9 to 11, wherein the hydrophobin derivative is used in an amount of from 10 to 150 ppm based on the overall composition.