CA2942998C - A method for improving paraffinic froth treatment process in oil sands extraction - Google Patents

Abstract

An unfiltered paraffinic froth treatment (PFT) process. A method for improving a paraffinic froth treatment (PFT) process in oil sands extraction includes identifying a flow path from a bitumen froth storage tank outlet, through a froth feed pump flow passage, a mixer flow passage, a debris filter flow passage, and a froth settling unit flow passage, to a tailings solvent recovery unit inlet passage, identifying a minimum flow passage size in the flow path, excluding the debris filter flow passage, and enlarging the flow path to at least the minimum flow passage size, and removing the debris filter from the flow path, wherein a filterless PFT process is provided.

Description

A METHOD FOR IMPROVING PARAFFINIC FROTH TREATMENT PROCESS IN OIL
SANDS EXTRACTION
FIELD
The present disclosure relates generally to the field of oil sands processing.
More particularly, the present disclosure relates to paraffinic froth treatment.
BACKGROUND
This section is intended to introduce various aspects of the art, which may be associated with the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure.
Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
Separation of bitumen from oil sands causes the formation of a bitumen-aqueous slurry (i.e. bitumen froth) which contains a significant amount of contaminants, namely water (20-50%) and mineral solids (10-30%). The bitumen froth is subjected to a paraffinic froth treatment (PFT) process, in which the bitumen froth is diluted with a hydrocarbon solvent to reduce the viscosity and density of the oil phase, thereby accelerating the settling of the solid and water impurities. Furthermore, the addition of the paraffinic solvent destabilizes asphaltenes in the bitumen, causing them to precipitate out as solids. These precipitated asphaltene solids agglomerate with the mineral solids and water in the slurry to form large flocs, which settle rapidly in gravity settlers. One example high temperature PFT process is designed to reject approximately 40-50 wt% of the asphaltenes in the bitumen to yield a clean and dry bitumen product with significantly low solids content.
At a high level, PFT serves to separate water and solids from the bitumen in a bitumen froth. Most of the water and solids, along with precipitated asphaltenes, end up in the tailings from the PFT. The degree of bitumen recovery is therefore an important parameter in PFT.
Figure us a simplified flow diagram of a conventional paraffinic froth treatment (PFT) process. Bitumen froth (2) is pumped from a froth storage tank (FST) (30) by a froth feed pump (FFP) (40) .to a 1st stage froth settling unit (FSU1) (100) to produce a 1st stage hydrocarbon-rich overflow (240) and a 1st stage solids-rich underflow (110).
Solvent (4) is removed from the 1st stage hydrocarbon-rich overflow (240) in a solvent recovery unit (SRU) (9) to produce a bitumen product (6).
The 1st stage solids-rich underflow (110) is mixed with a solvent stream (4) from the solvent recovery unit (SRU) (9) and is fed to a 2nd stage froth settling unit (FSU2) (160). The 2nd stage froth settling unit (FSU2) (160) produces a 2nd stage hydrocarbon-rich overflow (250) and a 2nd stage solids-rich underflow (170). The 2nd stage hydrocarbon-rich overflow (250) is added to the 1st stage froth settling unit (FSU1) (100) as a solvent source and may be combined with the bitumen froth (2) and mixed via a 1st stage mixer (70) to form an FSU
feedstream before its addition to the 1st stage froth settling unit (FSU1) (100) via feed line (80), as illustrated. The 2nd stage solids-rich underflow (170) is passed to a tailings solvent recovery unit (TSRU) (8). The TSRU (8) produces tailings (230) which are sent to an external tailings area (ETA) (246). Typically, there are only two froth settling unit (FSU) stages as illustrated with 1st stage froth settling unit (FSU1) (100) and 2nd stage froth settling unit (FSU2) (160), but optionally a 3rd stage froth settling unit (FSU3) may also be utilized in series and is also contemplated herein.
Upstream of the 1st stage froth settling unit (FSU1) (100), a debris filter (60) is used to restrict entry of large size debris (e.g., petrified wood, geotextile materials, coal particles, organic matter, etc.) coming into the PFT system with the bitumen froth (2) from the mine site. Due to the quantity of large debris in the bitumen froth (2), the debris filter (60) tends to fill up or become plugged frequently.
To clear the debris filter (60), the debris filter (60) is periodically shut-in and backwashed with a water stream (45) in a backwash cycle. The resulting backwash stream (245), containing the filtered debris, water, and residual bitumen froth and solvent is mixed with tailings (230) from the TSRU (8) and directed to the external tailings area (ETA) (246).
As the debris filter (60) frequently fills up or becomes restricted/plugged, a large number of backwash cycles are required. The use of the conventional debris filter (60), while designed to protect plugging in the downstream equipment, results in additional equipment and maintenance as well as significant losses of valuable hydrocarbon rich bitumen froth from the system due to the bitumen froth entrained in the backwash cycles. An additional problem is that the backwash stream (245) created by this filtering process contains these

- 2 -otherwise valuable hydrocarbons which now (as contaminants) need to be removed from the particulate matter in the backwash stream (245) to acceptable levels before the solids in the backwash stream (245) can be disposed of, preferably with the tailings (230) from the PFT
process. Fig. 1 illustrates where the backwash stream (245) may be sent to a flash drum (290) or "pump box" wherein the light hydrocarbons in the backwash stream (245) may be disengaged and sent to a flare system (300). However, even after flashing off these light hydrocarbons, the bitumen and a fraction of the solvent in the backwash stream (245) does not vaporize and end up as undesired contaminants in the external tailings area (ETA) (246).
In the simplified flow diagram of Fig. 1, only one stage of the TSRU (8) (a 1st stage TSRU) is shown. Optionally, embodiments may include a 2nd stage TSRU between the 1st stage TSRU and the external tailings area (ETA) (246).
Therefore, there is a need in the industry for an alternative or improved paraffinic froth treatment (PFT) process to recover bitumen which eliminates the generation of the backwash stream (245) from the paraffinic treatment (PFT) process.
SUMMARY
It is an object of the present disclosure to provide a paraffinic froth treatment (PFT) process to recover bitumen with lower solvent losses and contaminated debris handling.
Described is a filterless paraffinic froth treatment (PFT). Instead of filtering the bitumen froth, piping and vessel internals are enlarged to be tolerant of large debris from the inlet to the PFT to the TSRU tailings system. The inventors have found that the SRU system does not require any modifications, as any debris will leave the system via the froth settling unit (FSU) underflow due to the density of the overflow product in the froth settling unit (FSU).
The modifications may include replacing static mixers with dual plate open style mixing elements, removing and/or increasing flow passage sizes on FSU feed inlet baffle plates, increasing pump flow passage size, and revising control valve internals to increase the open flow passage size.
The debris typical of an oils sands mining operation reports to froth settling unit underflow due to density difference and gravity with the media and also asphaltene precipitation.

- 3 -In a first aspect, the present disclosure provides a method for improving a paraffinic froth treatment (PFT) of bitumen froth including identifying a flow path, from a bitumen froth storage tank (FST) outlet through a froth feed pump (FFP) flow passage, a debris filter flow passage, a mixer flow passage, and a froth settling unit (FSU) flow passage, to a tailings solvent recovery unit (TSRU) inlet passage, identifying a minimum flow passage size in the flow path, excluding the debris filter flow passage, enlarging the flow path to at least the minimum flow passage size, and removing the debris filter from the flow path, wherein a filterless PFT process is provided.
In an embodiment disclosed, the flow path further includes a TSRU column chimney opening and a TSRU underflow pump.
In an embodiment disclosed, enlarging the flow path includes enlarging the FSU
flow passage and the TSRU inlet passage.
In an embodiment disclosed, the flow path includes associated pipes and valves, and the enlarging includes enlarging the associated pipes and valves to at least the minimum flow passage size.
[0001] In an embodiment disclosed, the flow path includes associated control valves, and the enlarging includes enlarging the associated control valves to at least the minimum flow passage size.
In an embodiment disclosed, the minimum flow passage size is the FFP flow passage size.
In an embodiment disclosed, enlarging the FSU flow passage includes removing a baffle plate from a FSU feed barrel.
In an embodiment disclosed, enlarging the TSRU inlet passage includes enlarging TSRU inlet valve seat plate openings.
In an embodiment disclosed, enlarging the mixer flow passage includes replacing mixers with dual plate open geometry mixing elements.
In an embodiment disclosed, the dual plate open geometry mixing elements comprise SulzerTM (KVM Type) or KomaxTM mixers.
In an embodiment disclosed, the minimum flow passage size is between about 1.75 and about 3.75 inches.
In an embodiment disclosed, the minimum flow passage size is about 2.5 inch.

- 4 -In an embodiment disclosed, an accumulator is provided between the FSU and a solvent recovery unit (SRU) and floating debris is skimmed from the accumulator to remove debris that did not report to a solids-rich underflow of the FSU.
In a further aspect, the present disclosure provides a paraffinic froth treatment (PFT) process for bitumen froth including conveying unfiltered bitumen froth from a bitumen froth storage tank (FST) to a froth settling unit (FSU), the unfiltered bitumen froth containing large debris, providing solvent to the FSU, separating by density in the FSU, substantially all of the large debris to a FSU underflow, and conveying the FSU underflow to a tailings solvent recovery unit (TSRU).
In an embodiment disclosed, the large debris includes petrified wood, geotextile material, coal particles, organic particulate matter, or a combination thereof.
In an embodiment disclosed, at least 50% by volume of the large debris is less than about 2.5 inches in diameter.
In an embodiment disclosed, at least a portion of the large debris is greater than about 1/4 inches in diameter.
In an embodiment disclosed, the process includes separating, by precipitation in the FSU, asphaltenes to the FSU underflow.
In an embodiment disclosed, the process includes slipstream filtering overflow from the FSU, to remove floating debris from the FSU.
In an embodiment disclosed, the floating debris is removed by skimming.
In a further aspect, the present disclosure provides an unfiltered paraffinic froth treatment (PFT) system including a froth feed pump (FFP) having a FFP flow passage, a mixer having a mixer flow passage, a froth settling unit (FSU) having a FSU
flow passage, a solvent recovery unit (SRU) having a SRU flow passage, and a tailings solvent recovery unit (TSRU) having a TSRU inlet passage, wherein the FFP flow passage, the mixer flow passage, the FSU flow passage, and the TSRU inlet passage are adapted to allow the free passage of debris.
In an embodiment disclosed, the debris includes petrified wood or geotextile material, coal particles, organic particulate matter, or a combination thereof.
In an embodiment disclosed, the debris is large debris, able to pass through a 2.5 inch mesh sieve.

- 5 -In an embodiment disclosed, the mixer includes dual plate open geometry mixing elements.
In an embodiment disclosed, the mixer is a SulzerTM (KVM Type) or KomaxTM
mixer.
In an embodiment disclosed, each of the FFP flow passage, the mixer flow passage, the FSU flow passage, and the TSRU inlet passage is at least 2.5 inches.
In an embodiment disclosed, the FSU further includes a slipstream filter downstream of an overflow from the FSU, adapted to skim floating debris from the FSU.
Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached Figures.
Fig. 1 is a simplified flow diagram of a conventional paraffinic froth treatment (PFT) process.
Fig. 2 is a simplified flow diagram of a FSU, TSRU, and SRU of a PFT process.
Fig. 3 is a feed barrel of the present disclosure.
Fig. 4 is a detail of the feed barrel of Fig. 3 along the section 4-4 showing details of the feed barrel baffle plate.
Fig. 5 is an exemplary graph of pressure drop and bitumen production rate in relation to a SRU feed heat exchanger of the SRU of Fig. 2.
Fig. 6 is an exemplary illustration of debris observed during testing.
Fig. 7 is an exemplary graph of pressure drop between FSU1 and FSU2.
Fig. 8 is an exemplary visualization of a computer flow simulation of a feed barrel with baffle plate.
Fig. 9 is an exemplary visualization of a computer flow simulation of the feed barrel of Fig. 8, with the baffle plate removed.
Fig. 10 is an exemplary illustration of a control valve internal components.

- 6 -Fig. 11 is an exemplary illustration of the control valve internal components of Fig. 10, having a reduced number of enlarged orifices.
Fig. 12 is a simplified flow diagram of a FSU and TSRU of a filterless PFT
process of the present disclosure.
DETAILED DESCRIPTION
For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the features illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications, and any further applications of the principles of the disclosure as described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. It will be apparent to those skilled in the relevant art that some features that are not relevant to the present disclosure may not be shown in the drawings for the sake of clarity.
The PFT process may comprise at least three units: Froth Separation Unit (FSU), Solvent Recovery Unit (SRU) and Tailings Solvent Recovery Unit (TSRU). Mixing of the solvent with the feed bitumen froth may be carried out counter-currently in two stages in separate froth separation units. The bitumen froth comprises bitumen, water, and solids. A
typical composition of bitumen froth is about 60 wt.% bitumen, 30 wt.% water, and 10 wt.%
solids. The paraffinic solvent is used to dilute the froth before separating the product bitumen by gravity. The foregoing is only an example of a PFT process and the values are provided by way of example only. An example of a PFT process is described in Canadian Patent No.
2,587,166 to Sury.
At the outset, for ease of reference, certain terms used in this application and their meaning as used in this context are set forth below. To the extent a term used herein is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in at least one printed publication or issued patent. Further, the present processes are not limited by the usage of the terms shown below, as all equivalents, synonyms, new developments and terms or processes that serve the same or a similar purpose are considered to be within the scope of the present disclosure.

- 7 -Throughout this disclosure, where a range is used, any number between or inclusive of the range is implied.
A "hydrocarbon" is an organic compound that primarily includes the elements of hydrogen and carbon, although nitrogen, sulfur, oxygen, metals, or any number of other elements may be present in small amounts. Hydrocarbons generally refer to components found in heavy oil or in oil sand. However, the techniques described are not limited to heavy oils but may also be used with any number of other reservoirs to improve gravity drainage of liquids. Hydrocarbon compounds may be aliphatic or aromatic, and may be straight chained, branched, or partially or fully cyclic.
"Bitumen" is a naturally occurring heavy oil material. Generally, it is the hydrocarbon component found in oil sand. Bitumen can vary in composition depending upon the degree of loss of more volatile components. It can vary from a very viscous, tar-like, semi solid material to solid forms. The hydrocarbon types found in bitumen can include aliphatics, aromatics, resins, and asphaltenes. A typical bitumen might be composed of:
19 weight (wt.) % aliphatics (which can range from 5 wt. % - 30 wt. %, or higher);
19 wt. % asphaltenes (which can range from 5 wt. % - 30 wt. %, or higher);
30 wt. % aromatics (which can range from 15 wt. % - 50 wt. %, or higher);
32 wt. % resins (which can range from 15 wt. % - 50 wt. %, or higher); and some amount of sulfur (which can range in excess of 7 wt. %), the weight %
based upon total weight of the bitumen.
In addition, bitumen can contain some water and nitrogen compounds ranging from less than 0.4 wt. % to in excess of 0.7 wt. %. The percentage of the hydrocarbon found in bitumen can vary. The term "heavy oil" includes bitumen as well as lighter materials that may be found in a sand or carbonate reservoir.
The term "solvent" as used in the present disclosure should be understood to mean either a single solvent, or a combination of solvents.
The term "paraffinic solvent" (also known as aliphatic) as used herein means solvents comprising normal paraffins, isoparaffins or blends thereof in amounts greater than 50 wt. c/o.
Presence of other components such as olefins, aromatics or naphthenes may counteract the function of the paraffinic solvent and hence may be present in an amount of only 1 to 20 wt.
% combined, for instance no more than 3 wt. %. The paraffinic solvent may be a C4 to 020

- 8 -or C4 to 06 paraffinic hydrocarbon solvent or a combination of iso and normal components thereof. The paraffinic solvent may comprise pentane, iso-pentane, or a combination thereof.
The paraffinic solvent may comprise about 60 wt. % pentane and about 40 wt. %
iso-pentane, with none or less than 20 wt. % of the counteracting components referred above.
The terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numeral ranges provided.
Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and are considered to be within the scope of the disclosure.
The articles "the", "a" and "an" are not necessarily limited to mean only one, but rather are inclusive and open ended so as to include, optionally, multiple such elements.
Figure 2 illustrates a simplified exemplary PFT process. One may identify a flow path, starting with a bitumen froth (2) from a bitumen froth storage tank, (FST) (30), through a froth feed pump, (FFP) (40), through a debris filter (60), through a 1st stage mixer (70) and to a 1st stage froth settling unit (FSU1) (100) via feed line (80). A 1st stage feed barrel (90) (see Fig.
3) having a baffle plate (95) (see Fig. 4) is provided at the inlet of the feed line (80) to the 1st stage froth settling unit (FSU1) (100).
The flow path continues, in the 1st stage solids-rich underflow (110) from the 1st stage froth settling unit (FSU1) (100) through the 1st stage underflow pump (120), through a 2'd stage mixer (130), to a 2nd stage froth settling unit (FSU2) (160) via feed line (140). A 2nd stage feed barrel (150) (see Fig. 3) having a baffle plate (155) (see Fig. 4) is provided at the inlet of the feed line (140) to the 2nd stage froth settling unit (FSU2) (160).
The flow path continues, in the 2' stage solids-rich underflow (170) from the 2nd stage froth settling unit (FSU2) (160), through a 1st stage tailings solvent recovery unit (TSRU) inlet valve (190) to a 1st stage tailings solvent recovery unit (TSRU) column (195).
The flow path continues, through the 1st stage TSRU column chimney opening (196) and on to the 1st stage TSRU underflow (197) from the 1st stage TSRU column (195) through

- 9 -a 1st stage TSRU underflow pump (200), through a 2nd stage TSRU inlet valve (210) to a 2nd stage TSRU column (215).
The flow path continues, through the 2nd stage TSRU column chimney opening (216) and on to the 2nd stage TSRU underflow (217) from the 2nd stage TSRU column (215) through a 2nd stage TSRU underflow pump (220), tailings (230) are conveyed to an external tailings area (246). It should be noted that while Figure 2 is illustrated for purposes of discussion with a TSRU comprising two stages, TSRU systems with only one stage are also contemplated in embodiments herein.
Returning to the 2nd stage froth settling unit (FSU2) (160), the 2nd stage hydrocarbon-rich overflow (250) flows through a 2nd stage accumulator (270), 2nd stage accumulator bottoms pump (275), and is added to the 1st stage froth settling unit (FSU1) (100) as a solvent source and may be combined with the bitumen froth (2) before its addition to the 1st stage froth settling unit (FSU) (100), as illustrated.
The 1st stage hydrocarbon-rich overflow (240) flows to solvent recovery unit (SRU) (9) through a 1st stage accumulator (260) via a 1st stage accumulator bottoms pump (265).
The solvent recovery unit (SRU) (9) includes equipment known in the art to recover solvent from the 1st stage hydrocarbon-rich overflow (240) to provide bitumen product (6), which includes but is not limited to heaters, columns, condensers, etc. (not shown). A major concern for plugging is that in the first part of the flow system (not shown) of the solvent recovery unit (SRU) (9), the 1st stage hydrocarbon-rich overflow (240) passes through one or more SRU feed heat exchangers to heat the 1st stage hydrocarbon-rich overflow (240) to aid in the solvent recovery process. The SRU feed heat exchangers tend to have tube side or shell side minimum flow paths that are as small as 1/4 inch (particularly on the shell side passes).
In table form, the illustrated major components include:
Froth Feed Pump (FFP) (40) 1st Stage Mixer (70) 1st Stage Froth Settling Unit (FSU1) (100) 1st Stage Feed Barrel (90)! Baffle Plate (95) 1st Stage Underflow Pump (120)

-10-2nd Stage Mixer (130) 2nd Stage Froth Settling Unit (FSU2) (160) 2nd Stage Feed Barrel (150)! Baffle Plate (155) 2nd Stage Underflow Valve (180) 1st Stage TSRU Inlet Valve (190) 1st Stage TSRU Column (195) Chimney Opening (196) 1st Stage TSRU Underflow Pump (200) 2nd Stage TSRU Inlet Valve (210) 2nd Stage TSRU Column (215) Chimney Opening (216) 2nd Stage TSRU Underflow Pump (220) 1st Stage Accumulator (260) 1st Stage Accumulator Bottoms Pump (265) 2nd Stage Accumulator (270) 2nd Stage Accumulator Bottoms Pump (275) SRU Feed Heat Exchangers (not shown in Figures) To protect the PFT process equipment downstream from the froth feed pump (FFP) (40) from debris, a debris filter (60) having an opening size is traditionally provided. The SRU
(9) is particularly susceptible to debris, as the minimum flow passage of the SRU feed heat exchangers may be in the order of 1/4 inches. As the SRU (9) cannot tolerate large debris, a conventional PFT process may use the debris filter (60) having an opening size no larger than about 1/4 to about 1/ inches.
Due to the problems associated with the debris filter (60) operation as described above, the inventors enlarged the opening size of the debris filter (60) to 1 inch and monitored the pressure drop across a number of components in the PFT process and conducted surveillance at a number of points in the PFT process.
Referring to Fig. 5, in the SRU (9), the pressure drop (400) across the SRU
feed heat exchanger was monitored and found to be insignificant. As illustrated, the maximum pressure

- 11 -drop (400) encountered was about 20 kPa. The pressure drop (400) trends with the bitumen production rate (410), and surveillance showed no indication of plugging.
The 1st stage froth settling unit (FSU1) (100) (see Fig. 2) was drained to conduct surveillance. Minimal debris was found. Referring to Fig. 6, an exemplary sample of debris (420) is illustrated, ranging in size from about 1/4 inch x 1/4 inch to 1 inch by about 2.5 inch.
The debris (420) was observed to be generally pliable, fibrous, with orange-colored fibers visible.
Significantly, it was discovered that the debris in the system that made its way to the 1st stage froth settling unit (FSU1) (100) was only observed in the underflow of the vessels, i.e. the 1st stage solids-rich underflow (110), and not observed in the overflow of the vessel, i.e. 1st stage hydrocarbon-rich overflow (240). Thus, it was discovered that debris was ending up in the FSU underflows destined for the TSRU (8), and not flowing to the SRU (9).
Therefore, using a small opening size for the debris filter (60) to protect the SRU (9) was unnecessary. The inventors thus investigated the flow path between the froth feed pump (FFP) (40) and the ETA (246).
Referring to Fig. 7, in the FSU, the pressure drop (430) between the 1st stage froth settling unit (FSU1) (100) and the 2nd stage froth settling unit (FSU2) (160) was monitored.
As illustrated, the pressure drop (430) reached a maximum of about 150 kPa.
Less than about 5 kPa of frictional pressure drop (430) was expected based on hydraulic calculations and was observed when the equipment was in a new and clean condition, indicating that the 2nd stage feed barrel (150) was plugging. Inspection of the 2nd stage feed barrel (150) confirmed that plugging was occurring primarily at the baffle plate (155).
Within the debris flow path of an exemplary PFT process, each component has an open flow passage, for example:
Component Flow Passage (Example) Froth Feed Pump (FFP) (40) 2 inch 1st Stage Mixer (70) 1.5 inch 1st Stage Froth Settling Unit 1.5 inch

-12-(FSU1) (100) 1st Stage Feed Barrel (90)!
Baffle Plate (95) 1st Stage Underflow Pump 2 inch (120) 2nd Stage Mixer (130) 1.5 inch 2nd Stage Froth Settling Unit 1.5 inch (FSU2) (160) 2nd Stage Feed Barrel (150)!
(Baffle Plate (155) 1st Stage TSRU Inlet Valve 1.5 inch (190) 1st Stage TSRU Column (195) 6 inch Chimney Opening (196) 1st Stage TSRU Underflow 2 inch Pump (200) 2nd Stage TSRU Inlet Valve 1.5 inch (210) 2nd Stage TSRU Column (215) 6 inch Chimney Opening (216) 2nd Stage TSRU Underflow 2 inch Pump (220) Referring to the above, during the testing with the debris filter (60) having a 1 inch opening, it was discovered that debris of less an about 1 inch should readily move through the flow path, as the smallest flow passage is 1.5 inch. However, within the flow path, one can establish a selected minimum flow passage. That is, each component in the flow path shall have or be modified to have a flow passage equal to or larger than the selected minimum flow passage. For example, if the selected minimum flow passage was set at 2 inches, the flow passage for each of the 1st stage mixer (70), the 1st stage feed barrel (90) /

-13-baffle plate (95), the 2nd stage mixer (130), the 2nd stage feed barrel (150)!
baffle plate (155), the 1st stage TSRU inlet valve (190), and the second stage TSRU inlet valve (210), would be enlarged to at least 2 inches. In another example, if the selected minimum flow passage was set at 2.5 inches, the flow passage for each of the froth feed pump (40), 1st stage mixer (70), the 1st stage feed barrel (90) / baffle plate (95), the 1st stage underflow pump (120), the 2nd stage mixer (130), the 2nd stage feed barrel (150) / baffle plate (155), the 1st stage TSRU inlet valve (190), the 1st stage TSRU underflow pump (200), the second stage TSRU
inlet valve (210), and the 2nd stage TSRU underflow pump (220) would be enlarged to at least 2.5 inches.
In an embodiment disclosed, the selected minimum flow passage size may be selected based on one of the components in the flow path. As an example, the selected minimum flow passage above is 2 inch, based on the froth feed pump (FFP) (40) having a flow passage of 2 inch. Each flow passage of the other components in the flow path is thus enlarged (as necessary) to at least the minimum flow passage size and the debris filter (60) removed from the flow path.
Depending on the nature of the equipment and its flow passage, some flow passages may be enlarged by modification or replacement with larger components, some flow passages may be enlarged by removal of restrictive components, some flow passages may be enlarged by replacing the equipment with a different type or style, or some flow passages may be enlarged by one or more of the above or combinations thereof.
In relation to the 1st stage froth settling unit (FSU1) (100) and the 2nd stage froth settling unit (FSU2) (160), openings in the baffle plate (95) and baffle plate (155) may be enlarged or the flow passage may be enlarged through the removal of the baffle plate (95) and baffle plate (155). A computer simulation of the operation of the 1st stage feed barrel (90) and 2nd stage feed barrel (150) (see also Figs. 3 and 4) was performed. In particular, referring to Figs. 8 and 9, the computer simulation indicated that removal of the baffle plates (95) and (155) from the respective 1st stage feed barrel (90) and the 2nd stage feed barrel (150) would have little impact on the flow distribution. In the present example, the baffle plate (95) and the baffle plate (155) are removed.
In relation to static mixers, the 1st stage mixer (70), 2nd stage mixer (130), or other mixers may include plates that form open, intersecting channels in which the flow is divided

- 14-into many channels, for example a SulzerTM SMV type mixer. The flow passage may be enlarged by enlarging the channels, but one may elect to replace the 2nd stage mixer (130) with an alternate type of mixer to enlarge the flow passage. One suitable alternate type of mixer includes a vortex mixer or a dual plate mixer, typically having mixing elements with an opening between them (open geometry), for example a SulzerTM KVM or a KomaxTM
type mixer. In an embodiment disclosed, the 1st stage mixer (70) is similarly replaced.
In relation to control valves, the 1st stage TSRU inlet valve (190), 2nd stage TSRU inlet valve (210), or other control valves may include a valve seat plate (320) typically having several orifices (330) of a relatively small diameter (see Fig. 10). To enlarge the flow passage, one may replace or modify the control valve or at least the valve seat plate (320) to provide at least one larger orifice (340). To maintain the open area, fewer orifices (340) may be required than orifices (330). Referring to Figs. 10 and 11 as an example, a valve seat plate (320) having ten orifices (330) of about 1.5 inch diameter (17.67 square inches open area) could be replaced or modified to provide a valve seat plate (320) having four orifices (340) of about 2.5 inch diameter (19.64 square inches open area). Alternately, one may elect to replace the control valve with a different type of valve having a larger flow passage.
Referring to Fig. 12, after enlargement, the flow path includes, for example:
Component Flow Passage Froth Feed Pump (FFP) (40) 2.5 inch Debris Filter (60) removed 1st Stage Mixer (70) 2.5 inch minimum 1st Stage Froth Settling Unit 2.5 inch minimum (Baffle Plate (FSU1) (100) (95) removed) 1st Stage Feed Barrel (90) 1st Stage Froth Settling Unit 2.75 inch Underflow Pump (120) 2nd Stage Mixer (130) 2.5 inch minimum 2nd Stage Froth Settling Unit 2.5 inch minimum (Baffle Plate (FSU2) (160) (155) Removed)

-15-2nd Stage Feed Barrel (150) 1st Stage TSRU Inlet Valve 2.5 inch minimum (190) 1st Stage TSRU Column (195) > 6 inch Chimney Opening (196) 1st Stage TSRU Underflow 3.7 inch Pump (200) 2nd Stage TSRU Inlet Valve 2.5 inch minimum (210) 2nd Stage TSRU Column (215) > 6 inch Chimney Opening (216) 2nd Stage TSRU Underflow 3.7 inch Pump (220) Within the flow path, the above equipment is connected by associated piping and valves, and while the major associated piping (e.g. feed line (80), feed line (140)) and major associated valves (e.g. 1st stage TSRU inlet valve (190), and 2nd stage TSRU
inlet valve (210)) are shown, additional associated piping and valves are not shown, but which are similarly enlarged as necessary to at least the selected minimum flow passage size (in the above example, 2.5 inch).
As described above, the flow path is enlarged in a retrofit example, but similar flow path and flow passage analysis and selection may be done during initial design or construction of the PFT (10) from the outset.
In operation, the bitumen froth (2) may include large debris. In an embodiment disclosed, the large debris may be, for example, about 1 inch to 2.5 inch debris. The debris may include petrified wood, geotextile material, coal particles, organic particulate matter, or a combination thereof. In an embodiment disclosed, at least 50% by volume of the large debris is less than about 2.5 inches in diameter. In an embodiment disclosed, at least a portion of the large debris is greater than about 1/4 inches in diameter.

- 16-If the bitumen froth (2) contains large debris, e.g. in froth storage tank (FST) (30), the debris may pass unfiltered through the PFT (10) from the froth feed pump (FFP) (40) through the 1st stage mixer (70) to the 1st stage froth settling unit (FSU1) (100) through the 1st stage feed barrel (90).
The debris, separated by density or gravity or both in the 1st stage froth settling unit (FSU1) (100) will be conveyed substantially into the 1st stage solids-rich underflow (110). The debris in the 1st stage solids-rich underflow (110) may pass unfiltered to the 2nd stage froth settling unit (FSU2) (160) through the 2nd stage mixer (130) and the 2nd stage feed barrel (150).
Again, the debris, separated by gravity or density or both in the 2nd stage froth settling unit (FSU2) (160) will be conveyed into the 2nd stage solids-rich underflow (170), and on through the 1st stage TSRU inlet valve (190), through the chimney opening (196) of the 1st stage TSRU column (195), through the 1st stage TSRU underflow pump (200), through the 2nd stage TSRU inlet valve (210), through the chimney opening (216) of the 2nd stage TSRU
column (215), through the 2nd stage TSRU underflow pump (220), and end up with the tailings (230) directed to the external tailing area (ETA) (246).
In the event that debris ends up in the 1st stage hydrocarbon-rich overflow (240) from the 1st stage froth settling unit (FSU1) (100), the present disclosure provides for this contingency by including the option to use a slip-stream filter downstream of the 1st stage hydrocarbon-rich overflow (240) from the 1st stage froth settling unit (FSU1) (100). Floating debris may be skimmed from the 1st stage accumulator (260) to remove debris that did not report to the 1st stage solids-rich underflow (110) of the 1st stage froth settling unit (FSU1) (100).
Similarly, an option to use a slip-stream filter downstream of the 2nd stage hydrocarbon-rich overflow (250) from the 2nd stage froth settling unit (FSU2) (160) is contemplated. Floating debris may be skimmed from the 2nd stage accumulator (270) to remove debris that did not report to the 2nd stage solids-rich underflow (170) of the 2nd stage froth settling unit (FSU2) (160).
It should be understood that numerous changes, modifications, and alternatives to the preceding disclosure can be made without departing from the scope of the disclosure.
The preceding description, therefore, is not meant to limit the scope of the disclosure.

- 17-Rather, the scope of the disclosure is to be determined only by the appended claims and their equivalents. It is also contemplated that structures and features in the present examples can be altered, rearranged, substituted, deleted, duplicated, combined, or added to each other.

-18-

Claims (22)

CLAIMS:

1. A method for improving a paraffinic froth treatment (PFT) of bitumen froth comprising:
identifying a flow path, from a bitumen froth storage tank (FST) outlet through a froth feed pump (FFP) flow passage, a debris filter flow passage, a mixer flow passage, and a froth settling unit (FSU) flow passage, to a tailings solvent recovery unit (TSRU) inlet passage; identifying a minimum flow passage size in the flow path, excluding the debris filter flow passage;
enlarging the flow path to at least the minimum flow passage size; and removing the debris filter from the flow path, wherein a filterless PFT process is provided.

2. The method of claim 1, wherein the flow path further includes a TSRU
column chimney opening and a TSRU underflow pump.

3. The method of claim 1, wherein enlarging the flow path comprises enlarging the FSU
flow passage and the TSRU inlet passage.

4. The method of claim 1, wherein the flow path includes associated pipes and valves, and the enlarging includes enlarging the associated pipes and valves to at least the minimum flow passage size.

5. The method of claim 1, wherein the flow path includes associated control valves, and the enlarging includes enlarging the associated control valves to at least the minimum flow passage size.

6. The method of claim 1, wherein the minimum flow passage size is the FFP
flow passage size.

7. The method of claim 1, wherein enlarging the FSU flow passage includes removing a baffle plate from a FSU feed barrel.

8. The method of claim 1, wherein enlarging the TSRU inlet passage includes enlarging TSRU inlet valve seat plate openings.

9. The method of claim 1, wherein enlarging the mixer flow passage includes replacing mixers with dual plate open geometry mixing elements.

10. The method of claim 1, wherein the minimum flow passage size is between About 1.75 and about 3.75 inches.

11. The method of claim 10, wherein the minimum flow passage size is about 2.5 inches.

12. The method of claim 1, further comprising providing an accumulator between the FSU
and a solvent recovery unit (SRU) and skimming floating debris from the accumulator to remove debris that did not report to a solids-rich underflow of the FSU.

13. A paraffinic froth treatment (PFT) process for bitumen froth comprising:
conveying unfiltered bitumen froth from a bitumen froth storage tank (FST) to a froth settling unit (FSU), the unfiltered bitumen froth containing large debris;
providing solvent to the FSU;
separating by density in the FSU, substantially all of the large debris to a FSU
underflow; and conveying the FSU underflow to a tailings solvent recovery unit (TSRU);
wherein the large debris includes petrified wood, geotextile material, coal particles, organic particulate matter, or a combination thereof; and at least a portion of the large debris is greater than 'Xi inches in diameter.

14. The process of claim 13, wherein at least 50% by volume of the large debris is less than 2.5 inches in diameter.

15. The process of claim 13, further comprising separating, by precipitation in the FSU, asphaltenes to the FSU underflow.

16. The process of claim 13, further comprising slipstream filtering overflow from the FSU, to remove floating debris from the FSU.

17. The process of claim 16, wherein the floating debris is removed by skimming.

18. An unfiltered paraffinic froth treatment (PFT) system comprising: a froth feed pump (FFP) having a FFP flow passage;
a mixer having a mixer flow passage;
a froth settling unit (FSU) having a FSU flow passage;
a solvent recovery unit (SRU) having a SRU flow passage; and a tailings solvent recovery unit (TSRU) having a TSRU inlet passage, wherein the FFP flow passage, the mixer flow passage, the FSU flow passage, and the TSRU inlet passage are adapted to allow the free passage of large debris; and each of the FFP flow passage, the mixer flow passage,. the FSU flow passage, and the TSRU inlet passage is at least 2.5 inches; and at least a portion of the large debris is greater than % inches in diameter.

19. The system of claim 18, wherein the debris includes petrified wood or geotextile material, coal particles, organic particulate matter, or a combination thereof.

20. The system of claim 18, wherein the debris is large debris, able to pass through a 2.5 inch mesh sieve.

21. The system of claim 18, wherein the mixer includes dual plate open geometry mixing elements.

22. The system of claim 18, wherein the FSU further comprises a slipstream filter downstream of an overflow from the FSU, adapted to-skim floating debris from the FSU.