DEMULSIFIER INJECTION SYSTEM FOR FROTH TREATMENT PRODUCT QUALITY ENHANCEMENT

Abstract

A method of improving the quality of diluted bitumen product in a bitumen froth treatment process is provided comprising: adding a demulsifier to bitumen froth to produce a mixture of bitumen froth and demulsifier, wherein the demulsifier is added at a dosage sufficient to reduce bitumen water content in the diluted bitumen product; subjecting the mixture of bitumen froth and demulsifier to a mixing energy input of greater than about 100 J/kg; adding a hydrocarbon diluent to the mixed mixture of bitumen froth and demulsifier to produce a diluent diluted bitumen froth; and subjecting the diluent diluted bitumen froth to a separation process to produce the diluted bitumen product. In one embodiment, demulsifier is first added to naphtha to form a demulsifier-diluent mixture which is then added to bitumen froth to form a diluted bitumen froth prior to subjecting the diluted bitumen froth to a mixing energy input of greater than about 100 J/kg.

Description

FIELD OF THE INVENTION

The present invention relates generally to a method of improving the quality of diluted bitumen product through better mixing by adding demulsifier at a specific treatment location and dosage in a gravity-based or centrifuge-based bitumen froth treatment process.

BACKGROUND OF THE INVENTION

Oil sand deposits such as those found in the Athabasca Region of Alberta, Canada, generally comprise water-wet sand grains held together by a matrix of viscous heavy oil or bitumen. Bitumen is a complex and viscous mixture of large or heavy hydrocarbon molecules which contain a significant amount of sulfur, nitrogen and oxygen. Oil sands processing involves extraction of bitumen as froth and bitumen froth treatment to produce diluted bitumen which is further processed to produce synthetic crude oil and other valuable commodities.

Extraction is typically conducted by mixing the oil sand in hot/warm water and aerating the resultant slurry to promote the attachment of bitumen to air bubbles, creating a lower-density bitumen froth which floats and can be recovered in a primary separation vessel or “PSV” (generally referred to as primary bitumen froth). Sand grains sink and are concentrated in the bottom of the PSV. They leave the bottom of the vessel as a wet tailings stream containing a small amount of bitumen. Middlings, a watery mixture containing fine solids and bitumen, extend between the froth and sand layers. The wet tailings and middlings are separately withdrawn, combined and sent to a secondary flotation process. This secondary flotation process is commonly carried out in a deep cone vessel (a “TOR” vessel) wherein air is sparged into the vessel to assist with flotation. The bitumen recovered by flotation in the TOR vessel is generally recycled to the PSV. The middlings from the deep cone vessel are further processed in induced air flotation cells to recover contained bitumen as secondary bitumen froth.

Froth treatment is the process of reducing water and solids contents from the bitumen froths produced by the PSV and other secondary flotation processes to produce a clean bitumen product (i.e., “diluted bitumen”) for downstream upgrading processes. It has been conventional to dilute this bitumen froth with a light hydrocarbon diluent, for example, with naphtha, to increase the difference in specific gravity between the bitumen and water and to reduce the bitumen viscosity, to thereby aid in the separation of the water and solids from the bitumen. This diluent diluted bitumen froth is commonly referred to as “dilfroth.” It is desirable to “clean” dilfroth, as both the water and solids pose fouling and corrosion problems in upgrading refineries. By way of example, the composition of naphtha-diluted bitumen froth typically might have a naphtha/bitumen ratio of 0.65 and contain 20% water and 7% solids. It is desirable to reduce the water and solids content to below about 3% and about 1%, respectively.

Separation of the bitumen from water and solids may be done by treating the dilfroth in a series of scroll and/or disc centrifuges. Alternatively, the dilfroth may be subjected to gravity separation in a series of inclined plate separators (“IPS”) in conjunction with countercurrent solvent extraction using added light hydrocarbon diluent. However, these treatment processes still result in bitumen product often containing undesirable amounts of solids and water. Product solids lead to increased wear of downstream equipment, higher maintenance costs, and unplanned capacity losses and outages. Since the contents of the product solids and water are related, reducing water is a means of removing solids. Chemical demulsification is an effective means of reducing product water (and hence also product solids) from diluted bitumen.

In a gravity-based process, demulsifier is generally added after naphtha is injected into bitumen froth prior to transport to the IPS. The dosage of demulsifier is generally constant at about 35 ppm. However, it was observed that increasing the dosage from 35 to 50 ppm does not impact the product water content. In a centrifuge-based process, an increase in demulsifier dosage also has no impact on product water content. An inline mixer may be added to improve the mixing of the demulsifier and dilfroth, however, it was hypothesized that better demulsifier mixing may still be required.

Accordingly, there is a need to develop a better mixing method for enhancing the demulsifier performance to improve the quality of diluted bitumen product in bitumen froth treatment processes.

SUMMARY OF THE INVENTION

The current application is directed to a method of improving the quality of diluted bitumen product (i.e., reducing the water and solids content) by adding demulsifier at a specific treatment location and dosage in a gravity- or centrifuge-based bitumen froth treatment process. It was surprisingly discovered that by conducting the method of the present invention, one or more of the following benefits may be realized:

(1) The effectiveness of demulsifier to reduce diluted bitumen water content is significantly enhanced by sufficient mixing.

(2) With sufficient mixing, demulsifier is more effective in reducing diluted bitumen water content when added directly to naphtha or froth rather than to diluted froth.

(3) In a gravity-based process, sufficient mixing occurs when demulsifier is added to the froth just prior to the froth entering a pumping apparatus which is used to transport the bitumen froth (i.e., at the suction or inlet side of a froth pump).

(4) In a centrifuge-based process, sufficient mixing occurs when demulsifier is added to the froth at the suction of froth feed pump.

(5) At the suction side of the froth feed pump, the energy input is on the order of 300 J/kg which is an order of magnitude higher than the energy input at conventional locations where demulsifier is typically injected. This level of energy input is found to be effective to enhance the demulsifier performance. Addition of demulsifier at the pump suction is optimal for mixing and does not require any capital investment on mixing equipment.

(6) Increasing the dosage of demulsifier further decreases the diluted bitumen water content.

Use of the present invention improves the performance of demulsifier to reduce bitumen water and solids content, thereby in turn improving bitumen product (i.e., diluted bitumen or “dilbit”) quality. Reduction of solids content minimizes wear of downstream equipment, maintenance costs, and unplanned capacity losses and outages.

Thus, broadly stated, in one aspect of the invention, a method of improving the quality of diluted bitumen product in a bitumen froth treatment process is provided, comprising:

• • adding demulsifier to bitumen froth to produce a mixture of bitumen froth and demulsifier, wherein demulsifier is added at a dosage sufficient to reduce bitumen water content in the diluted bitumen product;
  • subjecting the mixture of bitumen froth and demulsifier to a mixing energy input of greater than about 100 J/kg;
  • adding a hydrocarbon diluent to the sufficiently mixed mixture of bitumen froth and demulsifier to produce a diluent diluted bitumen froth; and
  • subjecting the diluent diluted bitumen froth to a separation process to produce the diluted bitumen product.

In one embodiment, the separation process involves the use of at least one gravity settler, at least one centrifuge, at least one filter, or any combination thereof. In one embodiment, the energy input is between about 200 J/kg to about 350 J/kg. In one embodiment, the dosage of demulsifier ranges up to about 50 ppm. In one embodiment, the demulsifier content is in the range of about 1 ppm to about 50 ppm. In one embodiment, the mixing energy is provided by adding the demulsifier to the bitumen froth at a suction side of a pump.

In another aspect of the invention, a method of improving the quality of diluted bitumen product in a bitumen froth treatment process is provided, comprising:

• • adding a demulsifier to a hydrocarbon diluent to form a demulsifier-diluent mixture;
  • adding the demulsifier-diluent mixture to bitumen froth to produce a diluted bitumen froth and subjecting the diluted bitumen froth to a mixing energy input of greater than about 100 J/kg; and
  • subjecting the mixed diluted bitumen froth to a separation process to produce the diluted bitumen product.

In one embodiment, the separation process involves the use of at least one gravity settler, at least one centrifuge, at least one filter, or any combination thereof. in one embodiment, the energy input is between about 200 J/kg to about 350 J/kg. In one embodiment, the amount of demulsifier-diluent mixture added to bitumen froth results in the diluted bitumen froth having a naphtha to bitumen ratio of about 0.5 to about 1.0 and a demulsifier content of up to about 50 ppm. In one embodiment, the demulsifier content is in the range of about 1 ppm to about 50 ppm. In one embodiment, the mixing energy is provided by adding the demulsifier to the bitumen froth at a suction side of a pump.

DESCRIPTION OF THE DRAWINGS

Referring to the drawings wherein like reference numerals indicate similar parts throughout the several views, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein:

FIG. 1 is a diagram showing, in general, a prior art froth treatment process.

FIG. 2 is a diagram showing, in general, one embodiment of a froth treatment process of the present invention.

FIG. 3 is a diagram showing, in general, another embodiment of a froth treatment process of the present invention.

FIG. 4 is a graph showing the effect of improved mixing on diluted bitumen water content (%) over settling time (min).

FIG. 5 is a graph showing the effect of adding demulsifier to diluted froth, naphtha, and froth with sufficient mixing on diluted bitumen water content (%) over settling time (min).

FIG. 6 is a diagram showing the demulsifier addition to the suction of froth feed pump feeding IPS.

FIG. 7 is a graph showing the effect of adding demulsifier (20 ppm) to froth at the suction side of the froth pump versus addition to naphtha diluted froth after the froth pump (base case or prior art) on diluted bitumen water content for IPS unit.

FIG. 8 is a graph showing the effect of adding demulsifier (50 ppm) to froth at the suction side of the froth pump versus addition to naphtha diluted froth after the froth pump (base case or prior art) on diluted bitumen water content for IPS unit.

FIG. 9 is a diagram showing the demulsifier addition to the suction of froth feed pump feeding the centrifuges.

FIG. 10 is a graph showing the effect of adding different demulsifier dosages (20 and 35 ppm) to froth on diluted bitumen water content for centrifuge unit.

FIG. 11 is a graph showing the effect of adding demulsifier (50 ppm) to froth at the suction side of the froth pump versus addition to naphtha diluted froth after the froth pump (base case or prior art) on diluted bitumen water content for centrifuge unit.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

The present invention relates generally to a method of improving the quality of diluted bitumen product by adding demulsifier at a specific treatment location and dosage in a gravity- or centrifuge-based froth treatment process. Demulsification is an effective means of removing water from diluted bitumen. As used herein, the term “demulsifier” refers to an agent which breaks emulsions or causes water droplets either to coalesce and settle, or to flocculate and settle in flocs. Demulsifiers are commonly formulated from the following types of chemistries: polyglycols and polyglycol esters, ethoxylated alcohols and amines, ethoxylated resin, ethoxylated phenol formaldehyde resins, ethoxylated nonylphenols, polyhydric alcohols, ethylene oxide, propylene oxide block copolymer fatty acids, fatty alcohols, fatty amine and quaternaries and sulfonic acid salts.

FIG. 1 is a general schematic of a conventional gravity-based froth treatment process using gravity settlers. As used herein, the term “gravity-based” process refers to an operation in which diluted bitumen is separated from water and solids using gravity, and is therefore distinguished from other separation operations such as molecular sieve processes, absorption processes, adsorption processes, magnetic processes, electrical processes, and the like. As used herein, the term “gravity settler” refers to any suitable apparatus which facilitates gravity settling including, but not limited to, a gravity settling vessel and an inclined plate separator (“IPS”). As used herein, the term “IPS” refers to an apparatus comprising a plurality of stacked inclined plates onto which a mixture to be separated may be introduced so that the mixture passes along the plates in order to achieve separation of components of the mixture.

Bitumen froth 10 is initially received from an extraction facility which extracts bitumen from oil sand using a water extraction process known in the art. The bitumen froth 10, as received, typically comprises about 60% bitumen, about 30% water and about 10% solids. The bitumen froth 10 is pumped via froth pump 12 into line 14. A hydrocarbon diluent 16 is mixed with bitumen froth 10 as it moves through line 14 to provide diluent-diluted bitumen froth (dilfroth). In one embodiment, the hydrocarbon diluent 16 is naphtha (N). The naphtha is supplied in an amount such that the naphtha to bitumen ratio of the dilfroth is preferably in the range of 0.5 to 1.0, most preferably about 0.7.

Demulsifier (D) 18 is then added to the dilfroth as it continues to move through line 14 towards the inclined plate settler (“IPS”) 20. Demulsifier 18 is typically added at a dosage of about 35 ppm. The dilfroth and demulsifier can be mixed using an inline mixer 22 prior to feeding the dilfroth to inclined plate settler 20. As an example, with the inline mixer 22 bypassed, energy input for mixing is about 20 J/kg. With the inline mixer 22 online, the energy input increases to about 50 J/kg. However, it was discovered that an energy input of 50 J/kg was not sufficient and that the energy input required for adequate mixing of demulsifier with froth feed should be greater than 100 J/kg, preferably on the order of about 300 J/kg.

FIG. 2 is a general schematic of one embodiment of a froth treatment process of the present invention using gravity settlers. It is understood, however, that centrifuges can replace gravity settlers. As used herein, the term “centrifuge-based” process refers to an operation in which bitumen is separated from water and solids using centrifugal acceleration or centripetal acceleration resulting from rotational movement of a suitable apparatus including, but not limited to, a scroll centrifuge, disc centrifuge, hydrocyclone, propelled vortex separator, and the like.

Having discovered that a mixing energy of 50 J/kg was not sufficient, it was determined that demulsifier (D) 18 could be added at the suction side of the froth pump 12 to mix with the bitumen froth 10 as it is pumped via the froth pump 12 into line 14. Adding demulsifier 18 to the froth 10 and then pumping the mixture through froth pump 12 resulted in about 250 J/kg of mixing energy. In one embodiment, the concentration of demulsifier was about 35% based on active ingredient. A sufficient amount of demulsifier is added to yield the desired dosage. In one embodiment, the dosage of demulsifier ranges up to about 50 ppm.

A hydrocarbon diluent 16 is then added to the mixture of bitumen froth 10 and demulsifier 18 as it moves through line 14 to provide diluent-diluted bitumen froth-demulsifier. In one embodiment, the hydrocarbon diluent 16 is naphtha (N). The diluent-diluted bitumen froth-demulsifier may then bypass or, optionally, pass through the inline mixer 22 for additional mixing before being subjected to separation in the gravity settler 20. In one embodiment, the gravity settler 20 is an IPS. In one case, when demulsifier 18 is added at the suction side of the froth pump 12, the energy input for mixing is about 250 J/kg with the inline mixer bypassed and about 280 J/kg with the inline mixer online. The energy input thus approximates 300 J/kg which results in sufficient mixing of bitumen froth 10 and demulsifier 18. With proper mixing, demulsifier is more effective in reducing diluted bitumen water content. In one embodiment, the diluted bitumen water content is less than about 5 wt %.

FIG. 3 is a general schematic of another embodiment of a froth treatment process of the present invention using gravity settlers. It is understood, however, that alternatives such as centrifugation and filtration can replace gravity settlers. In this embodiment, demulsifier (D) is added to a hydrocarbon diluent such as naphtha (N) to give a demulsifier/diluents mixture 19 (D+N). The demulsifier/diluent mixture 19 is then added to froth 10 at the suction side of the froth pump 12 to mix with the bitumen froth 10 as it is pumped via the froth pump 12 into line 14. Adding demulsifier/diluent mixture 19 to the froth 10 and then pumping the mixture through froth pump 12 results in about 250 J/kg of mixing energy. In one embodiment, the concentration of demulsifier was about 35% based on active ingredient. A sufficient amount of demulsifier is added to yield the desired dosage. In one embodiment, the dosage of demulsifier ranges up to about 50 ppm.

The diluent-diluted bitumen froth-demulsifier may then bypass or, optionally, pass through the inline mixer 22 for additional mixing before being subjected to separation in the gravity settler 20. In one embodiment, the gravity settler 20 is an IPS. With the inline mixer online, about 280 J/kg of energy is input.

Exemplary embodiments of the present invention are described in the following Examples, which are set forth to aid in the understanding of the invention, and should not be construed to limit in any way the scope of the invention as defined in the claims which follow thereafter.

Example 1

Batch tests were conducted to determine whether ineffective demulsifier performance in the prior art froth treatment operation may be caused by inadequate mixing of the demulsifier into the naphtha diluted froth. A shaker table was used to simulate the energy input of the existing system (prior art) shown in FIG. 1. As can be seen in FIG. 4, when lower mixing energy is used, after 60 minutes settling time, the diluted bitumen water content was about 1.5%. An impeller and baffles were used to simulate a higher energy input for mixing other than pipe mixing. Improved mixing enhanced the effectiveness of demulsifier as indicated by the decrease in diluted bitumen water content, i.e., after 60 minutes settling time, the water content in the diluted bitumen was reduced to about 1.0%.

FIG. 5 shows that, with sufficient mixing, demulsifier was even more effective in decreasing diluted bitumen water content when added to naphtha or froth rather than to diluted froth. The results suggest that both sufficient mixing and the location of demulsifier addition are significant.

Example 2

Based on the results obtained in Example 1, a field demonstration was initiated using a gravity-based process (i.e., an inclined plate settler unit). The test system is shown in FIG. 6. Froth tank 200 fed froth 210 via line 211 to froth pump 212. Demulsifier 218 was added to the suction side of the froth pump 212 via line 217. This location provides sufficient mixing energy without significant changes to the operating system. A conservative estimate of the mixing energy input is around 250 J/kg with the inline mixer bypassed and about 30 J/kg higher with an inline mixer online, as shown in FIG. 2. This energy input is an order of magnitude higher than that of the original location of demulsifier addition (prior art). For comparison, in some runs, demulsifier was added at the original location shown in FIG. 1, i.e., after the froth pump.

Demulsifier 218 was shipped in totes 234 and provided a 35 wt % active injection concentrations (Emulsotron product #X2105, NALCO Champion An EcoLab Company). A progressive cavity chemical pump 230 maintained stable flow. A variable frequency drive (VFD) controller 232 installed on the pump skid controlled the pump speed. Using a VFD controller 232 and flowmeter 236, the demulsifier flow rate was set at a desired level to achieve a target dosage. The flowmeter 236 was calibrated to ensure stability and accuracy of the demulsifier flow rate. The measured froth flow rate was used to determine the demulsifier flow rate based on the target dosage. A pressure relief valve 238 was installed on the pump discharge line to open and divert flow back to the pump suction in response to overpressure. A check valve on the tied-in location prevented froth from entering the chemical system, thereby avoiding line plugging or contamination of the demulsifier. The demulsifier 218 was introduced into the froth pump suction through a ¾″ injection quill located 3¼″ from the wall inside a 24″ froth suction pipe. The discharge end of the quill was reduced to ⅜″ and fed the demulsifier at 45° in the direction of the flow.

i) IPS ON/OFF Test at a Demulsifier Dosage of 20 ppm

An ON/OFF test was conducted to determine the effect of adding demulsifier at an injection concentration of 35% to either naphtha diluted froth (i.e., after the froth pump), or to froth at the suction side of the froth pump. The diluted bitumen water content was measured using a water cut meter at the IPS product line. In FIG. 7, the step change shows the injection location and the dosage is constant at 20 ppm. The high setting refers to addition of demulsifier at the original location (prior art), and the low setting refers to the addition of demulsifier to the froth pump suction. The jagged line indicates the product water content. Before start-up, the demulsifier dosage to the IPS was set to 20 ppm for more than three hours (i.e., at least three times of the IPS residence time) and the IPS was stable. When the existing system was shut down, the test system was started immediately. There was a time delay between when the test system was started up and the time that demulsifier actually arrived in the IPS. When the test system was shut down, the original system was started up back to a dosage of 20 ppm. FIG. 7 shows a consistent pattern over the one hour interval of ON/OFF. When addition of the demulsifier switched from the original location to the froth pump suction, the water content in the IPS product dropped significantly from ˜2.4% to ˜1.4%. When demulsifier was added at the original location, the water content in IPS product increased. This example demonstrated that enhanced demulsifier mixing significantly reduced diluted bitumen product water.

ii) IPS ON/OFF Test at the Demulsifier Dosage of 50 ppm

The effect of demulsifier injection location at a dosage of 50 ppm was determined. FIG. 8 shows a similar trend of IPS product water content when switching demulsifier addition between the original (prior art) and test locations. Again, consistent with the results for the demulsifier dosage of 20 ppm, the diluted bitumen water reduction was also observed using the 50 ppm dosage through enhanced mixing in the suction of froth feed pump. In this case, the diluted bitumen water content significantly decreased down to 0.45%.

Example 3

A field demonstration was performed using two different units of centrifuges. Each unit comprises a series of centrifuges. The test system is shown in FIG. 9. Froth tank 300 feeds froth 310 via lines 311a and 311b to froth pumps 312a and 312b, respectively. Demulsifier 318 is added to the suction side of the froth pumps 312a and 312b via lines 317a and 317b, respectively. This location provides sufficient mixing energy without significant changes to the operating system. Historically, when using a centrifuge-based process, demulsifier is added after the first stage centrifuge.

As with FIG. 6, demulsifier 318 was shipped in totes 334 and provided a 35 wt % active injection concentrations (Emulsotron product #X2105, NALCO Champion An EcoLab Company). A progressive cavity chemical pump 330 maintained stable flow. A variable frequency drive (VFD) controller 332 installed on the pump skid controlled the pump speed. Using a VFD controller 332 and flowmeter 336, the demulsifier flow rate was set at a desired level to achieve a target dosage. The flowmeter 336 was calibrated to ensure stability and accuracy of the demulsifier flow rate. The measured froth flow rate was used to determine the demulsifier flow rate based on the target dosage. A pressure relief valve 338 was installed on the pump discharge line to open and divert flow back to the pump suction in response to overpressure. The demulsifier was introduced into the froth pumps 312a and 312b suctions through a ¼″ injection quill located 3¼″ from the wall inside a 24″ froth suction pipe. The discharge end of the quill was reduced to ⅜″ and fed the demulsifier at 45° in the direction of the flow.

i) Centrifuge Demulsifier Dosage Test

When demulsifier is added at the original location (i.e., after the first stage centrifuge, prior art), the product water content does not correlate with demulsifier dosage, and a change in demulsifier dosage does not affect product quality. The effects of different demulsifier dosages added at the test location (i.e., the suction side of the froth feed pumps) on product water content was determined (FIG. 10). Demulsifier dosage was calculated based on fresh froth feed rate. The rectangular-shaped step-change line labeled “demulsifier” indicates the demulsifier dosage and location. The jagged line labeled “water” indicates the product water content of the centrifuges. Prior to 11:00, demulsifier was added after the first stage centrifuge at a dosage of 35 ppm using the demulsifier active injection concentration of 35 wt %. The product water content was stable and constant before switching to the test system. When the test system was started, there was an initial product water content increase. This was due to the time delay between shut-down of the original system and start-up of the test system. The demulsifier active injection concentration remained at 35% with dosage starting at 20 ppm at the suction of the froth pump. The product water content decreased as the demulsifier dosage increased. This trend occurs up to 50 ppm. Similar to the tests in IPS units, enhanced mixing and increase demulsifier dosage resulted in a lower diluted bitumen water content.

ii) Centrifuge ON/OFF Test at the Demulsifier Dosage of 50 ppm

A test was conducted to assess demulsifier effectiveness at the original location (prior art) and at the froth feed pump suction. FIG. 11 shows the demulsifier performance results as a function of injection location. The rectangular-shaped step-change line labeled “demulsifier” indicates the demulsifier dosage and location. The jagged line labeled “water” is the product water content. The high setting represents the original location and the low setting is for the froth pump suction. The dosage was constant at 50 ppm. Before start-up, the demulsifier dosage was set at 50 ppm and production was relatively stable. When the test system was started, there was an initial product water content increase. This was due to the time delay between shut-down of the original system and start-up of the test system resulting in no demulsifier. The product water content thus increased until the demulsifier reached the target dosage in the feed to the centrifuge, leading to a decrease in water content. When the demulsifier injected from the test system arrived at the centrifuges, the product water contents dropped immediately to a level much lower than that through the original system. When the test system was shut down and the original system was back online, the water content returned to a level higher than that through the test system. This on/off test again supported the concept of enhanced mixing improved the demulsifier effectiveness in diluted bitumen product water reduction

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention. However, the scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

1. A method of improving the quality of diluted bitumen product in a bitumen froth treatment process comprising:

adding a demulsifier to bitumen froth to produce a mixture of bitumen froth and demulsifier, wherein the demulsifier is added at a dosage sufficient to reduce water content in the diluted bitumen product;

subjecting the mixture of bitumen froth and demulsifier to a mixing energy input of greater than about 100 J/kg;

adding a hydrocarbon diluent to the mixed mixture of bitumen froth and demulsifier to produce a diluent diluted bitumen froth; and

subjecting the diluent diluted bitumen froth to a separation process to produce the diluted bitumen product.

2. The method of claim 1, wherein the active chemical concentration of the demulsifier is about 35%.

3. The method of claim 2, wherein the dosage of the demulsifier ranges from about 1 ppm to about 50 ppm.

4. The method of claim 1, wherein the demulsifier comprises a polyglycol, a polyglycol ester, an ethoxylated alcohol or amine, an ethoxylated resin, an ethoxylated phenol formaldehyde resin, an ethoxylated nonylphenol, a polyhydric alcohol, ethylene oxide, a propylene oxide block copolymer fatty acid, a fatty alcohol, a fatty amine, a quaternary, or a sulfonic acid salt.

5. The method of claim 1, wherein mixing energy input is provided by adding the demulsifier to the bitumen froth at a suction side of a pump.

6. The method of claim 1, wherein mixing energy input is about 300 J/kg.

7. The method of claim 1, wherein the diluted bitumen water content is less than about 5 wt %.

8. The method of claim 1, wherein the hydrocarbon diluent is naphtha.

9. The method of claim 8, wherein naphtha is added in an amount such that the naphtha to bitumen ratio of the diluent diluted bitumen froth is in the range of about 0.5 to about 1.0.

10. The method of claim 9, wherein naphtha is added in an amount such that the naphtha to bitumen ratio of the diluent diluted bitumen froth is about 0.7.

11. The method of claim 1, wherein the separation process involves the use of at least one gravity settler, at least one centrifuge, at least one filtration system or a combination thereof.

12. The method of claim 1, wherein the separation process involves the use of a series of centrifuges.

13. The method of claim 12, wherein at least one centrifuge in series is a scroll centrifuge and at least one centrifuge in series is a disc centrifuge.

14. The method of claim 1, wherein the separation process involves the use of at least one gravity separator.

15. The method of claim 14, wherein the at least one gravity separator is an inclined plate settler.

16. A method of improving the quality of diluted bitumen product in a bitumen froth treatment process, comprising:

adding a demulsifier to a hydrocarbon diluent to form a demulsifier-diluent mixture;

adding the demulsifier-diluent mixture to bitumen froth to produce a diluted bitumen froth and subjecting the diluted bitumen froth to a mixing energy input of greater than about 100 J/kg; and

subjecting the mixed diluted bitumen froth to a separation process to produce the diluted bitumen product.

17. The method of claim 16, wherein the active chemical concentration of the demulsifier is about 35%.

18. The method of claim 17, wherein the dosage of the demulsifier ranges from about 1 ppm to about 50 ppm.

19. The method of claim 16, wherein the demulsifier comprises a polyglycol, a polyglycol ester, an ethoxylated alcohol or amine, an ethoxylated resin, an ethoxylated phenol formaldehyde resin, an ethoxylated nonylphenol, a polyhydric alcohol, ethylene oxide, a propylene oxide block copolymer fatty acid, a fatty alcohol, a fatty amine, a quaternary, or a sulfonic acid salt.

20. The method of claim 16, wherein mixing energy input is provided by adding the demulsifier-diluent mixture to the bitumen froth at a suction side of a pump.

21. The method of claim 16, wherein mixing energy input is about 300 J/kg.

22. The method of claim 16, wherein the diluted bitumen water content is less than about 5 wt %.

23. The method of claim 16, wherein the hydrocarbon diluent is naphtha.

24. The method of claim 23, wherein the naphtha concentration in the demulsifier-diluent mixture is such that the naphtha to bitumen ratio of the diluted bitumen froth is in the range of about 0.5 to about 1.0.

25. The method of claim 24, wherein naphtha concentration in the demulsifier-diluent mixture is such that the naphtha to bitumen ratio of the diluted bitumen froth is about 0.7.

26. The method of claim 16, wherein the separation process involves the use of at least one gravity settler, at least one centrifuge, at least one filter or a combination thereof.

27. The method of claim 16, wherein the separation process involves the use of a series of centrifuges.

28. The method of claim 27, wherein at least one centrifuge in series is a scroll centrifuge and at least one centrifuge in series is a disc centrifuge.

29. The method of claim 16, wherein the separation process involves the use of at least one gravity separator.

30. The method of claim 29, wherein the at least one gravity separator is an inclined plate settler.