WO2011091501A1

WO2011091501A1 - Method and apparatus for heating bitumen slurry stored in a tank

Info

Publication number: WO2011091501A1
Application number: PCT/CA2010/001136
Authority: WO
Inventors: Grant W. Hiebert; Steven Bradwell; Jack W. Fenkhuber; Nathan Q. Illerbrun; Gerald W. Clancy; Colin D. Mcmaster; Grant W. Meikle
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-01-28
Filing date: 2010-07-22
Publication date: 2011-08-04
Anticipated expiration: 2012-07-28
Also published as: CA2691389A1

Abstract

An internal combustion engine powers a head pump to pump bitumen slurry from a well borehold. A storage tank stores the bitumen slurry at a location adjacent to a CHOPS site. Hot exhaust from the engine flows along an exhaust conduit and into an exhaust-to-glycol heat exchanger. The glycol is pumped in a recirculating circuit from the exhaust-to-glycol heat exchanger into and through a glycol-to-bitumen slurry heat exchanger to thereby heat the bitumen slurry in the storage tank. Cooled glycol is recirculated back through the exhaust-to-glycol heat exchanger. Engine coolant may be inter-mingled with the glycol flowing into the glycol-to-bitumen slurry heat exchanger. Alternatively, engine coolant is pumped through a second heat exchanger, an engine coolant-to-glycol in series with the exhaust-to-glycol heat exchanger, to boost the temperature of the glycol entering the slurry heat exchanger.

Description

METHOD AND APPARATUS FOR HEATING BITUMEN SLURRY STORED IN A

TANK

Field of the Invention

This invention relates to the field of heating devices used to separate heavy oil from a bitumen slurry consisting of heavy oil, sand and water, and in particular to a method and apparatus for heating the bitumen slurry which uses recaptured heat from a well head pump power plant.

Background of the Invention

Many oil well sites in western Canada use an extraction method referred to as Cold Heavy Oil Production with Sand ("CHOPS"). These wells are typically small, remote sites that use a progressive cavity pump to draw a slurry or mixture of heavy oil, sand and water from the ground and pump it into a large on-site storage tank. It is estimated that over 3500 CHOPS wells currently exist in western Canada.

At each of these wells an internal combustion engine power plant is provided to generate the hydraulic power required to run the oil well pump. A large storage tank, for example of 750 or 1000 barrel capacity, is also provided at the site. It is used to contain the mixture of oil, sand and water which is extracted from the earth by the oil well pump. To be useful, for example so that the oil in the mixture may be processed for pumping through a pipeline, the mixture being pumped from the well must be separated during a primary separation process at the well site. The primary separation is achieved by maintaining the temperature of the mixture in the storage tank at approximately 80 degrees Celsius. At this temperature, the sand, water and oil in the mixture separates into distinct layers within the storage tank. Since the oil component of the mixture is typically too viscous to effectively flow in a pipeline, the oil once separated is regularly drained from the storage tank into tanker trucks and delivered to local "upgrader" facilities where the oil is processed and thinned in order to make it suitable for introduction into a pipeline network, The water that accumulates in the tank is drained as necessary and sand is also removed on a regular basis.

Unlike most light oil wells, CHOPS sites often do not produce adequate amounts of well gas to provide fuel either for the power plant engine that generates hydraulic power for the well head pump or for the prior art large burner-style tank heaters that are placed inside the storage tanks and used to heat the oil once it is in the storage tank. Consequently propane to be consumed by the engine and storage tank heater has to be brought to the well sites at great expense due to the remote location of the well site and lack of usable onsite gas. Next to the actual trucking of the oil, propane consumption accounts for the most significant cost in the production of CHOPS oil.

Applicant is aware of United States Patent No 7,726,298 which issued to St Denis on June 1, 2010 from an application filed March 8, 2004, entitled Method and Apparatus for Heating a Liquid Storage Tank. St. Denis discloses appending an engine compartment to the peripheral side wall of a liquid storage tank. An engine is disposed in the engine compartment. Heat given off f om the engine during operation heats the engine compartment and such heat is transferred through the peripheral sidewall to the interior of the liquid storage tank. An exhaust conduit extends into the interior of the liquid storage tank. Heat from hot exhaust gases passing through the exhaust conduit heats the interior of the liquid storage tank. St. Denis also discloses passing heated engine coolant through an engine coolant conduit positioned concentrically within the engine exhaust conduit leading from the engine so that heat from the engine coolant is added to the hot exhaust gases to further transmit heat the interior of the liquid storage tank. As claimed inter alia by St. Denis in corresponding Canadian Patent No. 2,421,384, which issued December 15, 2009, at least one conduit extends from the engine into the interior of the tank and back to the engine to circulate hot fluid from the engine through the conduit to thereby heat the interior of the tank. Summary of the Invention

An internal combustion engine is provided which powers a prime mover for a bitumen slurry well head pump used at a CHOPS site to pump bitumen slurry from a well borehole. A storage tank is also provided in a location adjacent to the CHOPS site. Bitumen slurry is pumped from the CHOPS site and stored in the storage tank. When running at its operating temperature the engine provides heated exhaust along an exhaust conduit and into an exhaust inlet of a first heat exchanger in an exhaust-to-heat transfer fluid heat exchanger. Heat transfer fluid, for example glycol, from the exhaust-to-heat transfer fluid heat exchanger is pumped into and through a second heat exchanger, namely, a heat transfer fluid-to-bitunaen slurry heat exchanger mounted in the storage tank to thereby heat the bitumen slurry in the storage tank.

The exhaust-to-heat transfer fluid heat exchanger includes: i) an engine exhaust duct having the exhaust inlet and an engine exhaust outlet in gas-flow communication along said exhaust duct with said exhaust inlet; and, ii) a heat transfer fluid duct having said exhaust duct adjacent to and isolated from said fluid duct so as to transfer heat but not said gas-flow or said fluid between said exhaust duct and said fluid duct. The engine exhaust is directed along an exhaust conduit from the engine into the engine exhaust inlet of the exhaust-to-heat transfer fluid heat exchanger. The heat transfer fluid is pumped by a heat transfer fluid pump from the heat transfer fluid inlet to the heat transfer fluid outlet of the exhaust-to-heat transfer fluid heat exchanger. Heat transfer fluid from the heat transfer fluid outlet of the exhaust-to-heat transfer fluid heat exchanger is directed along a heat transfer fluid conduit into the heat transfer fluid-to-bitumen slurry heat exchanger so as to transfer heat from the heat transfer fluid to bitumen slurry in the storage tank. The heat transfer fluid is re-circulated from the heat transfer fluid-to-bitumen slurry heat exchanger back to the heat transfer fluid inlet of the exhaust-to-heat transfer fluid heat- exchanger. The re-circulating circuit between the exhaust-to-heat transfer fluid heat exchanger and the heat transfer fluid-to-bitumen slurry heat exchanger re-circulates the beat transfer fluid continuously therealong.

The following are also advantageously provided: a) an inlet temperature sensor for monitoring temperature of the heat transfer fluid entering the heat transfer fluid inlet, b) an outlet temperature sensor for monitoring temperature of the heat transfer fluid exiting the exhaust-to-heat transfer fluid heat exchanger from the heat transfer fluid outlet. c) a selectively actuable flow diverter for diverting exhaust into an exhaust bypass to inhibit the exhaust from entering the exhaust inlet d) a controller and/or processor for comparing at least one of the monitored temperatures with a threshold temperature of the heat transfer fluid, wherein the threshold temperature maybe substantially an upper maximum desired temperature range of the heat transfer fluid, for example to avoid at least vapourization of the fluid, and if the monitored temperature substantially equals or exceeds the threshold temperature then the diverter is actuated to bypass the exhaust from the exhaust inlet and into the exhaust bypass.

The controller and/or processor also monitors at least one of the temperature sensors for a drop in temperature of the heat transfer fluid. When said temperature of the heat transfer fluid drops below the threshold temperature, the exhaust is directed back into said exhaust inlet.

Where the engine is liquid cooled and includes a radiator, so that liquid coolant circulates through the radiator and cools the engine, the method of the present invention may further include the step of capturing heat from the engine by directing the liquid coolant into the heat transfer fluid-to-bitumen slurry heat exchanger. Advantageously the liquid coolant is of the same composition as the heat transfer fluid. The liquid coolant thus is mingled with the heat transfer fluid, for example inter-mingled downstream of the radiator and downstream of the heat transfer fluid outlet of said exhaust-to-heat transfer fluid heat exchanger, and upstream of the heat transfer fluid-to-bitumen slurry heat exchanger, so that a mixture of the heat transfer fluid and the liquid coolant enters the heat transfer fluid-to-bitumen slurry heat exchanger. Further advantageously an engine coolant temperature sensor is provided to monitor the liquid coolant temperature. The liquid coolant is directed as between the radiator and the heat transfer fluid-to-bitumen slurry heat exchanger so as to maintain an operational engine temperature in the engine while optimizing heat transfer from the liquid coolant to the heat transfer fluid-to-bitumen slurry heat exchanger.

A bitumen slurry temperature sensor may be provided for monitoring the temperature of the bitumen slurry. The controller compares the bitumen slurry temperature and determines or estimates (herein collectively referred to as determines) when bitumen slurry separation has substantially occurred, whereupon the controller performs at least one further step chosen from the group: continue heating the bitumen slurry, reduce heating of the bitumen slurry, send out a signal indicating status of separation of the bitumen slurry.

The heat transfer fluid-to-bitumen slurry heat exchanger may include a helical or other coil heat exchanger, and die exhaust-to-heat transfer fluid heat exchanger may include a counter-flow heat exchanger. Brief Description of the Drawings

Figure 1 is a top perspective view of a portion of the apparatus according to the present invention including an internal combustion engine, an exhaust-to-heat transfer fluid heat exchanger and an exhaust bypass.

Figure 2 is in perspective view, a representation of a storage tank and one embodiment of a heat transfer fluid-to-bitumen slurry heat exchanger mounted therein.

Figure 3 is, in partially cut-away perspective view, the exhaust conduits of Figure 1 directing engine exhaust from the internal combustion engine of Figure 1 to an exhaust bypass and an exhaust-to-heat transfer fluid heat exchanger.

Figure 4 is, in schematic view, the exhaust, heat transfer fluid and engine coolant heat recapture circuits according to one aspect of the present invention.

Figure 5 is, an enlarged partially cut-away view of the heat exchanger Figure 2.

Figure 6 is, in partially cut-away perspective view, a further embodiment of a heat transfer fluid-to-bitumen slurry heat exchanger mounted in a storage tank.

Figure 6a is an enlarged partially cut-away view of the heat exchanger of Figure

6.

Figure 7 is a further embodiment of the heat exchanger system according to the present invention. Detailed Description of Embodiments of the Invention

The present invention reclaims heat that is currently wasted from the exhaust system and in a preferred embodiment also the cooling jacket of an internal combustion engine 10 used to power a hydraulic well pump. Engine 10 may run on propane, but this is not intended to be limiting as other fuel services would also work. The reclaimed heat from engine 10 is used to heat, and thereby to separate, a mixture of heavy oil (bitumen), sand and water (referred to herein as bitumen slurry) pumped by the well pump into an elevated storage tank 12. The exhaust gases from engine 10 are routed through an exhaust gas-to-heat transfer liquid heat exchanger 14. The heat transfer fluid (e.g. glycol) may in one embodiment be combined with the liquid coolant from the heated water jacket and radiator circuit 16 of engine 10. The heat transfer fluid heated in heat exchanger 14, in the preferred embodiment combined with the liquid coolant from circuit 16, is pumped in direction A by pump(s) 18 for the heat transfer fluid flowing through check valve(s) 20a in direction A' into the inlet port 36a of heat exchanger 14, and for the engine coolant circuit through, for example, diverter valve 20b into the inlet 22a of a heat transfer fluid-to-bitumen slurry heat exchanger 22 mounted in storage tank 12.

The temperature of the engine exhaust gas from engine 10 (which may typically be 800 degrees Celsius) will usually necessitate that controls be used to ensure that the glycol, or other heat transfer fluid, does not vapourize during the heat transfer process. A system of sensors and control software in a controller monitors the heat reclamation system according to the present invention and makes the necessary control decisions to prevent the vapourization of the heat transfer fluid (glycol) in heat exchanger 14. A pressure relieving system for example pressure relief valve 50, may be incorporated into heat exchanger 14 to allow the safe release of pressurized glycol gas in the event that vapourization occurs.

Figure 1 depicts one embodiment of exhaust heat exchanger 14 mounted on exhaust manifolds 10a of engine 10, Figure 3 is a further embodiment and is not intended to limiting. The various exhaust and fluid circuits for this embodiment of the present invention are illustrated schematically in Figure 4. Examples of storage tank 12 containing examples of heat exchanger 22 are illustrated in Figures 5 and 6.

In operation, during initial system startup the engine air drawn in through air intakes 10b and exiting the engine as exhaust bypasses the exhaust-to-glycol heat exchanger 14 by the operation of diverter valves 24a and 24b and is routed in direction B through conduit 26 to the engine exhaust silencer or muffler 28. During this time the engine liquid coolant is pumped by pump 30 through the water jacket of engine 10 and the engine radiator 32 in order to maintain adequate cooling of engine 10. Once it is determined by a controller (not shown) that by comparing measured glycol temperature with a known vapourization threshold temperature, and if the temperature of the circulating glycol is low enough to accept additional heat input without vapourizing the glycol, then the two exhaust diverter valves 24a and 24b are biased to divert the exhaust gas flow in direction C through heat exchanger 14. If the measured circulating glycol temperature is also below the maximum allowable engine cooling jacket temperature then the engine liquid coolant is diverted in direction D away from radiator 32 through check valve 34 so as to be mixed with the glycol outlet flow in direction A from heat exchanger 14. This glycol outlet flow from heat exchanger 14 exits from outlet port 36b into outflow conduit 38 (shown in dotted outline in Figure 1, partially cut-away, and in Figure 4) which carries the heated glycol through check valve 38a to inlet 22a of heat exchanger 22. The glycol circuit may include an expansion tank 38b and corresponding pressure relief valve 38c.

This combination of heated glycol from heat exchanger 14 and from radiator 32 is then circulated through storage tank heat exchanger 22 by pump(s) 18 and 30 respectively. Without intending to be limiting, heat exchanger 22 may be helical as in Figure 6, or, for example as seen in Figure 5, may be non-helical so long as heat from the glycol is transferred efficiently to the bitumen slurry 40 in tank 12. Once the temperature of the glycol that is leaving outlet 22b, returning in direction E to pump(s) 18 from storage tank heat exchanger 22, exceeds the maximum allowable engine cooling jacket temperature as measured for example by temperature sensor 42, the engine coolant is once again constrained by the actuation of valve 20b to circulate through engine radiator 32 in order to maintain adequate cooling of engine 10. The remaining circulating glycol is allowed to continue receiving heat from heat exchanger 14 until such time as either the desired bitumen slurry temperature is reached as measured by sensor 42 or the maximum safe temperature of the glycol is reached as indicated for example by a temperature sensor mounted in tank 12 or for example by measurements by temperature sensor 44. When either of these conditions occur, the engine exhaust from manifolds 10a and flowing through exhaust conduit 46 is diverted into bypass conduit 26 and thereby around exhaust heat exchanger 14 so as to flow directly into engine exhaust silencer 28. This control method is used to continuously monitor the temperature of the circulating glycol and add heat to it as required from either of the two engine heat sources.

If it is determined that there is not enough engine heat available to maintain an adequate bitumen slurry temperature in storage tank 12, an additional inline, gas fired glycol heater (not shown) may be used to supplement the heat provided by engine 10. These types of heaters are typically much more efficient than the burner type commonly used in the prior art as described above and therefore the amount of propane consumed by such gas-fired glycol heaters is less than typically encountered in the prior art.

In order to maintain a safe and controlled system, sensors 42, 44 are used to monitor the temperature and sensor 48 monitors flow rate of the glycol in the recirculation loop (A - E). The temperature is measured by sensor 42 just prior to the glycol coming into the recirculation glycol pump(s) 18, which may have parallel circuits as seen in dotted outline in Figure 4, and then again by sensor 44 just downstream of heat exchanger 14 and downstream of where heat transfer fluid (glycol) is mixed with the cooling jacket fluid (glycol also). Flow meter 48 is used to ensure that the glycol is flowing at an acceptable rate. If at any time the temperatures or flow rates are not within acceptable ranges, the controller actuates valves 24a, 24b to force the exhaust into conduit 26 to bypass heat exchanger 14 and ensure that the glycol does not vapourize due to excessive heat input. The sensors located in the circuit may also be used to provide data as to how much energy is being recovered and therefore, how much propane is not being consumed (such as would be consumed by the standard tank heater). To calculate the energy being recovered the temperature of the glycol is measured as it enters and exits the engine recirculation loop as well as the mass flow rate of the glycol.

Expansion joints 52 may be included on heat exchanger 14 and exhaust bypass

26.

The slurry that is pumped into the storage tank typically contains both oil and water. Conventionally, the slurry is pumped into the storage tank at the bottom of the tank, and droplets of oil in the slurry are then allowed to rise. The droplets of oil settle in an oil pool over the water below the oil. The water below the oil pool is herein referred to as the water zone or water portion of the storage tank. The oil pool is herein also referred to as the oil portion of the storage tank.

It has been found advantageous to heat the water portion in the bottom of the tank more gently then by the prior art methods in order to avoid boiling of the water. This allows heating of the droplets of oil in the water portion as they rise. In the prior art, direct heating of the water portion in the storage tank has been found to cause boiling, foaming and calcification. Consequently, in the present invention foaming-over conditions are avoided by using the lower temperature of the hot heat transfer fluid to more gently heat the water portion, thereby commencing heating of the pool of oil portion of the tank, starting with the oil when still in droplet form in the water portion. In other words, the boiling typically occurs when the water portion or water within the oil portion is heated. One advantage of the present invention is that the heat transfer system uses a lower temperature heat and therefore will not boil the water. This allows heating of the water layer directly and thus the oil droplets are within it. In prior art fire tube heating systems, the fire tubes, to applicant's knowledge, were located only in the oil portion of the storage tank. In particular they were located in the lower part of the oil portion. That placement of the fire tube limited the amount of oil or oil/water slurry that could be pumped out of the tank into tank trucks for transport to a refinery, because the oil or slurry could not be drawn down below the level of the fire tube when the fire tube was operational. In the present invention the heating of the water portion allows the tank to be drawn down further than could be achieved using the fire tube prior art.

Indeed, in the present invention, because direct heating from engine exhaust is not employed to heat the oil portion, when the present invention is used to heat the contents of the storage tank the tank may be drawn down completely. This allows for the cleaning of the tank, and in particular the cleaning out of sand which accumulates in the bottom of the tank. Applicants believe that the heating of the oil in the tank directly using exhaust gases risks explosion, for example if the exhaust conduit tube in the tank is exposed when the oil/slurry is drawn down, or if the exhaust conduct tube has a leak and, again, the tank is drawn down too far so as to expose the tube.

In one further embodiment of the present invention two heating zones may be employed, one in the lower, water portion and one higher up in the tank in the oil portion of the tank. Preferably then in this embodiment no direct engine fluids or gases such as the engine coolant or exhaust go directly from the engine into the storage tank.

In the further preferred embodiment, in order to assist heating the crude oil in the tank to the desired 80°C, an exhaust gas heat exchanger is used in series with, that is, in addition to and in-line with, the glycol (or other liquid coolant) heat exchanger. The additional heat recovery is thought to possibly add a further 5 - 10 °C to the heat transfer fluid in the tube going into the oil/slurry in the tank over the otherwise limiting temperature of the engine operating temperature. For example, if the engine coolant operating temperature is 98°C then the use of the two heat exchangers, one coolant, the other exhaust, in series may provide for a temperature of 108°C in the heat transfer fluid going into the storage tank. Thus in the further alternative embodiment of Figure 7, a second heat exchanger 54 is included in series with, and downstream of, heat exchanger 14. Heat exchanger 14 is, in the preferred embodiment, an engine coolant, for example, glycol heat exchanger, and heat exchanger 54 is an engine exhaust heat exchanger.

Coolant for heat exchanger 14 is pumped by motor 30a driving pumps 30, and diverted to the heat exchanger 14 by actuation of diverter valves 21a and 21b from the coolant circuit through radiator 32, radiator 32 having an associated radiator fan 32a. The particular form of heat exchanger used for heat exchangers 14 or 54, for example, whether linear counter-flow, helical coil, etc would be a design choice known to one skilled in the art. Advantageously, temperature sensors 44a and 44b are mounted, respectively, between heat exchangers 14 and 54, and downstream of heat exchanger 54. Gate valves 38b, 38c and 38d are provided, replacing one-way valve 38a in Figure 4, so as to regulate flow of heated heat transfer fluid into tank 12, and in particular into upper heat exchanger portion 22c corresponding to the oil portion of the tank, and, alternatively, also into lower heat exchanger portion 22d corresponding to the water portion of the tank.

Gate valves 18a and 18b-18d are associated with corresponding pumps 18 pumping heat transfer fluid through the heat exchangers 14 and 54.

Claims

WHAT IS CLAIMED IS:

1. A method for heating bitumen slurry stored in a storage tank, the method comprising the steps of: a) providing a heat transfer flmd-to-bitumen slurry heat exchanger mounted in the storage tank, b) providing an internal combustion engine external and adjacent to the storage tank, c) providing externally to the storage tank, an engine exhaust-to-heat transfer fluid heat exchanger comprising: i) an engine exhaust duct having an engine exhaust inlet and an engine exhaust outlet in gas-flow communication along said exhaust duct with said engine exhaust inlet; and, ii) a heat transfer fluid duct having said exhaust duct adjacent to and isolated from said fluid duct so as to transfer heat but not said gas-flow or said fluid between said exhaust duct and said fluid duct, d) providing an exhaust conduit, and directing exhaust, along said exhaust conduit, from said engine to said engine exhaust inlet of said exhaust-to-heat transfer fluid heat exchanger, e) providing a heat transfer fluid pump and pumping said heat transfer fluid from said heat transfer fluid inlet to said heat transfer fluid outlet of said exhaust-to- heat transfer fluid heat exchanger, f) providing a heat transfer fluid conduit, and directing said heat transfer fluid from said heat transfer fluid outlet of said exhaust-to-heat transfer fluid heat exchanger along said heat transfer fluid conduit, to said heat transfer fluid-to- bitumen slurry heat exchanger so as to transfer heat from said heat transfer fluid to bitumen slurry in the storage tank, g) providing a re-circulating conduit, and re-circulating said heat transfer fluid from said heat transfer fluid-to-bitumen slurry heat exchanger back through said re-circulating conduit to said heat transfer fluid inlet of said exhaust-to- heat transfer fluid heat-exchanger, wherein said exhaust is never within the storage tank so as to reduce the risk of explosion, boiling or foaming within the tank.

2. The method of claim 1 wherein said internal combustion engine powers a prime mover for a bitumen slurry well head pump used to pump bitumen slurry from a well borehole, and wherein said method further comprising the steps of: a) providing the storage tank in a location adjacent to the well site, b) storing bitumen slurry pumped from the well site in the storage tank, c) operating said engine so as to provide heated exhaust along said exhaust conduit and to said exhaust inlet of said exhaust-to-heat transfer fluid heat exchanger, d) pumping said heat transfer fluid from said exhaust-to-heat transfer fluid heat exchanger into and through said heat transfer fluid-to-bitumen slurry heat exchanger to thereby heat the bitumen slurry in said storage tank.

The method of claim 2 wherein said re-circulating conduit completes a re-circulating circuit between said exhaust-to-heat transfer fluid heat exchanger and said heat transfer fluid-to-bitumen slurry heat exchanger for re-circulation of said heat transfer fluid continuously therealong.

The method of claim 3 further comprising: a) providing an inlet temperature sensor and monitoring temperature of said heat transfer fluid entering said heat transfer fluid inlet, b) providing an outlet temperature sensor and monitoring temperature of said heat transfer fluid exiting said exhaust-to-heat transfer fluid heat exchanger from said heat transfer fluid outlet, c) providing an exhaust bypass to inhibit said exhaust from entering said exhaust inlet, d) comparing at least one of said monitored temperature with a threshold temperature of said heat transfer fluid, wherein said threshold temperature is substantially an upper maximum desired temperature range of said heat transfer fluid, and if said at least one of said monitored temperature substantially equals or exceeds said threshold temperature then bypassing said exhaust from said exhaust inlet and into said exhaust bypass, e) monitoring at least one of said temperature sensors for a drop in temperature of said heat transfer fluid.

The method of claim 1 -wherein said engine is cooled by liquid coolant, and wherein said method further comprises the step of capturing heat from said engine by providing a liquid coolant-to-heat transfer fluid heat exchanger in series with said exhaust-to-heat transfer fluid heat exchanger, and directing said liquid coolant, once heated by said engine, into said liquid coolant-to-heat transfer fluid heat exchanger and recirculating said liquid coolant back to said engine from said liquid coolant-to-heat transfer fluid heat exchanger.

The method of claim 4 wherein said engine is cooled by liquid coolant, and wherein said method further comprises the step of capturing heat from said engine by providing a liquid coolant-to-heat transfer fluid heat exchanger in series with said exhaust-to-heat transfer fluid heat exchanger, and directing said liquid coolant, once heated by said engine, into said liquid coolant-to-heat transfer fluid heat exchanger and recirculating said liquid coolant back to said engine from said liquid coolant-to-heat transfer fluid heat exchanger, and, further comprising the step of providing a second outlet temperature sensor and monitoring temperature of said heat transfer fluid exiting said liquid coolant-to-heat transfer fluid heat exchanger, providing a liquid coolant bypass to inhibit said liquid coolant from entering said liquid coolant-to-heat transfer fluid heat exchanger, and wherein if said at least one of said monitored temperature substantially equals or exceeds said threshold temperature then bypassing said liquid coolant from entering said liquid coolant-to-heat transfer fluid heat exchanger.

The method of claim 6 wherein when said temperature of said heat transfer fluid drops below said threshold temperature, directing said exhaust back into said exhaust inlet, and so long as engine temperature of said engine remains within an operational range, directing said liquid coolant back into said liquid coolant-to-heat transfer fluid heat exchanger.

8. The method of claim 2 wherein said engine is liquid cooled and includes a radiator, and wherein liquid coolant circulates through said radiator and cools said engine, said method further comprising the step of capturing heat from said engine by directing said liquid coolant into said heat transfer fluid-to-bitumen slurry heat exchanger.

9. The method of claim 8 wherein said liquid coolant is of the same composition as said heat transfer fluid, said method further comprising inter-mingling downstream of said radiator said liquid coolant with said heat transfer fluid downstream of said heat transfer fluid outlet of said exhaust-to-heat transfer fluid heat exchanger and upstream of said heat transfer fluid-to-bitumen slurry heat exchanger so that a mixture of said heat transfer fluid and said liquid coolant enters said heat transfer fluid-to-bitumen slurry heat exchanger.

10. The method of claim 9 further comprising providing an engine coolant temperature sensor and monitoring said liquid coolant temperature, and directing said liquid coolant as between said radiator and said heat transfer fluid-to-bitumen slurry heat exchanger so as to maintain an operational engine temperature in said engine while optimizing heat transfer from said liquid coolant to said heat transfer fluid-to-bitumen slurry heat exchanger.

11. The method of claim 6 further comprising providing a controller and, as part of said exhaust bypass, a separate exhaust conduit cooperating with at least one bypass diverter valve, said diverter valve and said temperature sensors communicating with said controller, said controller determining said comparison of said temperature relative to said threshold temperature and causing actuation of said at least one diverter valve.

12. The method of claim 7 further comprising providing a bitumen slurry temperature sensor and monitoring a bitumen slurry temperature of said bitumen slurry, said controller comparing said bitumen slurry temperature and determining when bitumen slurry separation has substantially occurred whereupon said controller performs at least one further step chosen from the group: continue heating said bitumen slurry, reduce heating of said bitumen slurry, send out a signal indicating status of separation of said bitumen slurry.

13. An apparatus for heating bitumen slurry stored in a storage tank, the apparatus comprising the: a) a heat transfer fluid-to-bitumen slurry heat exchanger adapted to only mount in the storage tank, b) an internal combustion engine external and adjacent to the storage tank, c) an engine exhaust-to-heat transfer fluid heat exchanger adapted to only mount externally to the storage tank and comprising: i) an engine exhaust duct having an engine exhaust inlet and an engine exhaust outlet in gas-flow communication along said exhaust duct with said engine exhaust inlet; and, ii) a heat transfer fluid duct having said exhaust duct adjacent to and isolated from said fluid duct so as to transfer heat but not said gas-flow or said fluid between said exhaust duct and said fluid duct, d) means for directing exhaust along an exhaust conduit from said engine into said engine exhaust inlet of said exhaust-to-heat transfer fluid heat exchanger, e) a heat transfer fluid pump and to pump said heat transfer fluid from said heat transfer fluid inlet to said heat transfer fluid outlet of said exhaust-to-heat transfer fluid heat exchanger, f) means for directing said heat transfer fluid from said heat transfer fluid outlet of said exhaust-to-heat transfer fluid heat exchanger along a heat transfer fluid conduit into said heat transfer fluid-to-bitumen slurry heat exchanger so as to transfer heat from said heat transfer fluid to bitumen slurry in the storage tank. g) means for re-circulating said heat transfer fluid from said heat transfer fluid-to- bitumen slurry heat exchanger back to said heat transfer fluid inlet of said exhaust-to-heat transfer fluid heat-exchanger, wherein said exhaust is never within the storage tank so as to thereby reduce the risk of explosion, boiling or foaming within the tank.

14. The apparatus of claim 13 further comprising a prime mover, wherein said internal combustion engine powers said prime mover, said prime mover for a bitumen slurry well head pump used to pump bitumen slurry from a well borehole, and wherein said apparatus further comprises: a) a storage tank locatable adjacent to a well site, b) means for operating said engine so as to provide heated exhaust along said exhaust conduit and to said exhaust inlet of said exhaust-to-heat transfer fluid heat exchanger, wherein said pump is for pumping said heat transfer fluid from said exhaust-to-heat transfer fluid heat exchanger into and through said beat transfer fluid-to-bitumen slurry heat exchanger to thereby heat the bitumen slurry in said storage tank,

15. The apparatus of claim 14 further comprising a re-circulating circuit of said heat transfer fluid conduits between said exhaust-to-heat transfer fluid heat exchanger and said heat transfer fluid-to-bitumen slurry heat exchanger for re-circulation of said heat transfer fluid continuously therealong.

The apparatus of claim 13 further comprising: a) an inlet temperature sensor for monitoring temperature of said heat transfer fluid entering said heat transfer fluid inlet, b) an outlet temperature sensor for monitoring temperature of said heat transfer fluid exiting said exhaust-to-heat transfer fluid heat exchanger from said heat transfer fluid outlet, c) an exhaust bypass adapted to inhibit said exhaust from entering said exhaust inlet, d) a controller processor fox comparing at least one of said monitored temperature with a threshold temperature of said heat transfer fluid, wherein said threshold temperature is substantially an upper maximum desired temperature range of said heat transfer fluid, and if said at least one of said monitored temperature substantially equals or exceeds said threshold temperature then bypassing said exhaust from said exhaust inlet and into said exhaust bypass, said processor adapted to monitor at least one of said temperature sensors for a drop in temperature of said heat transfer fluid.

The apparatus of claim 13 wherein said engine is cooled by liquid coolant, and further comprising a liquid coolant-to-heat transfer fluid heat exchanger mounted in fluid communication in series without said exhaust-to-heat transfer fluid heat exchanger to thereby serially heat said heat transfer fluid communicated between said heat exchangers, and further comprising flow diverters directing said liquid coolant, once heated by said engine, into said liquid coolant-to-heat transfer fluid heat exchanger and recirculating said liquid coolant back to said engine from said liquid coolant-to-heat transfer fluid heat exchanger.

18. The apparatus of claim 16 wherein said engine is cooled by liquid coolant, and further comprising a liquid coolant-to-heat transfer fluid heat exchanger mounted in fluid communication in series without said exhaust-to-heat transfer fluid heat exchanger to thereby serially heat said heat transfer fluid communicated between said heat exchangers, and further comprising flow diverters directing said liquid coolant, once heated by said engine, into said liquid coolant-to-heat transfer fluid heat exchanger and recirculating said liquid coolant back to said engine from said liquid coolant-to-heat transfer fluid heat exchanger.

19. The apparatus of claim 18 wherein as monitored by said processor, when said temperature of said heat transfer fluid drops below said threshold temperature, said controller directs said exhaust back into said exhaust inlet.

20. The apparatus of claim 14 wherein said engine is liquid cooled and includes a radiator, and wherein liquid coolant circulates through said radiator and cools said engine, and further comprising means for capturing heat from said engine by directing said liquid coolant into said heat transfer fluid-to-bitumen slurry heat exchanger.

The apparatus of claim 20 said liquid coolant is of the same composition as said heat transfer fluid, and further comprising means for inter-mingling downstream of said radiator said liquid coolant with said heat transfer fluid downstream of said heat transfer fluid outlet of said exhaust-to-heat transfer fluid heat exchanger and upstream of said heat transfer fluid-to-bitumen slurry heat exchanger so as to cause a mixture of said heat transfer fluid and said liquid coolant to enter said heat transfer fluid-to- bitumen slurry heat exchanger.

22. The apparatus of claim 21 further comprising an engine coolant temperature sensor to monitor said liquid coolant temperature, and means for directing said liquid coolant as between said radiator and said heat transfer fluid-to-bitumen slurry heat exchanger so as to maintain an operational engine temperature in said engine while optimizing heat transfer from said liquid coolant to said heat transfer fluid-to-bitumen slurry heat exchanger.

23. The apparatus of claim 18 further comprising providing a controller and, as part of said exhaust bypass, a separate exhaust conduit cooperating with at least one bypass diverter valve, said diverter valve and said temperature sensors adapted to communicate with said controller, said controller adapted to determine said comparison of said temperature relative to said threshold temperature and to cause actuation of said at least one diverter valve.

24. The apparatus of claim 19 further comprising a bitumen slurry temperature sensor communicating with said controller and wherein said controller is adapted to monitor a bitumen slurry temperature of said bitumen slurry, said controller adapted to compare said bitumen slurry temperature and to determine when bitumen slurry separation has substantially occurred whereupon said controller is adapted to perform at least one further step chosen from the group: continue heating said bitumen slurry, reduce heating of said bitumen slurry, send out a signal indicating status of separation of said bitumen slurry.

25. The method of claim 1 further comprising providing upper and a lower stage in said heat transfer fluid-to-bitumen heat exchanger so that said upper stage resides substantially in an oil portion of said storage tank and said lower stage resides substantially in a water portion of said storage tank, and heating the slurry in said tank by heating at least said lower stage. The apparatus of claim 13 further comprising upper and a lower stage in said heat transfer. Fluid-to-bitumen heat exchanger adapted so that said upper stage reside substantially in an oil portion of said storage tank when mounted therein, and said lower stage resides substantially in a water portion of said storage tank when mounted therein, whereby the slurry in said tank is heated by heating at least said lower stage.