Abstract:
A cascading processor is described which includes a processor body having an upper inlet and a lower outlet, such that materials pass by force of gravity from inlet to the outlet. The processor body has a plurality of processing levels Which are sequentially vertically spaced progressively downwardly from the inlet to the outlet, such that materials cascade by force of gravity from one processing level to another processing level as the materials pass through the processor body front the inlet to the outlet. This cascading processor was developed for recovery of bitumen front oil sands, but can be used to process oil shales or to process biomasses.

Description:
FIELD 
       [0001]    There is described a cascading processor that was developed for using in processing oil sands for heat extraction of bitumen and a method of using the same. It will be appreciated that the cascading processor can be used for processing other types of materials. 
       BACKGROUND 
       [0002]    Published patent application WO2010/115283 (Lourenco et al #1) entitled “Extraction and Upgrading of Bitumen from Oil Sands”, describes a heat extraction and upgrading process, which provides a number of advantages over existing processes. Patent Cooperation Treaty application CA2011/05043 (Lourenco et al #2) entitled “Method to Upgrade Heavy Oil in a Temperature Gradient”, describes a process which is focused upon heavy oil, not oil sands. If these types of heat extraction processes are to be used with oil sands, methods and apparatus must be developed which are better capable of handling highly abrasive oil sands, which cause wear mechanical product handling system. 
       SUMMARY 
       [0003]    According to one aspect there is provided a cascading processor which includes a processor body having an upper inlet and a lower outlet, such that materials pass by force of gravity from inlet to the outlet. The processor body has a plurality of processing levels which are sequentially vertically spaced progressively downwardly from the inlet to the outlet, such that materials cascade by force of gravity from one processing level to another processing level as the materials pass through the processor body from the inlet to the outlet. 
         [0004]    According to another aspect there is provided a method of processing materials including a step of passing the materials through a cascading processor having a processor body with an upper inlet and a lower outlet, such that the materials pass by force of gravity from inlet to the outlet. The processor body has a plurality of processing levels which are sequentially vertically spaced progressively downwardly from the inlet to the outlet, such that the materials cascade by force of gravity from one processing level to another processing level as the materials pass through the processor body from the inlet to the outlet 
         [0005]    The cascading processor and the associated method were developed to enable the efficient processing of abrasive oil sands. It will be appreciated that the cascading processor and the broadest aspect of the associated method can be used to process any material that is capable of flowing by force of gravity from one level to another. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein: 
           [0007]      FIG. 1  is a flow diagram illustrating a method for processing oil sands to extract bitumen using the cascading processor. 
           [0008]      FIG. 2  is a flow diagram illustrating the cascading processor of  FIG. 1 , with a variation in the lowermost processing level. 
           [0009]      FIG. 3  is a flow diagram illustrating the cascading processor of  FIG. 1 , with a variation to separate and compress hydrogen. 
           [0010]      FIG. 4  is a flow diagram illustrating the cascading processor of  FIG. 1 , with a variation to compress and control the addition of hydrogen and allow for separation and production of heavier fractions. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    A cascading processor and its method of operation will now be described with reference to  FIG. 1 through 4 . There will be used as an example the removal of bitumen from oil sands. 
       Overview of Process: 
       [0012]    The cascading processor provides a method to enable the extraction of water and oil from oil sands. The process main feature it&#39;s the ability to process large volumes of solids in a downwards cascading flow in a controlled temperature gradient. The second feature of the process is the intimate contact in each section by the countercurrent flow between the produced vapors and the oil bearing sands. The produced vapors are the sweeping gas stream and the oil bearing sands the reflux stream that quenchs the exothermic reactions. As shown in  FIG. 1 , the oil sands processor has six distinct sections, numbered  1  through  6 . 
         [0013]    The first section,  1 , is the deaeration section, it uses the waste heat of combustion flue gas streams to preheat and deaerate the oil sands. 
         [0014]    The second section,  2 , is the preheating section, it preheats the oil sands with a temperature controlled heat transfer fluid coil to evaporate all the water and lighter oil fractions with boiling points below the section controlled set temperature. The fractions with a boiling point greater than the preset temperature, cascade with the oil bearing sand to section three. The evaporated fractions from section  2  are cooled and separated into water, light oil fractions and fuel gas at separator  76 . The water is recovered and processed to generate steam in steam generator  83 . The condensed light oil fractions are recovered and added to the product stream in vessel  87 . The separated fuel gas enters the process fuel gas header  9 . 
         [0015]    The third section,  3 , is the flashing section, it has a bed immersed direct fired burner and a serpentine duct distributed into three zone in a upwards countercurrent flow to the cascading oil bearing sands. The bed level in each zone is controlled by longitudinal zone dividers. The temperature in the last zone of the section is controlled by combusting fuel gas in the immersed direct fired burner  11 . The bed temperatures in the subsequent upward zones are controlled by the flow of flue gases to each serpentine duct. The immersed burner  11  can be a pulse burner with resonance tubes radiating an acoustic pressure that enhances the mixing of solids and vapors in each zone. The zone beds are fluidized by a distributed countercurrent flow of product vapors generated in sections downstream. The solvent properties of product vapors enhance mass transfer, pre-heat the sands, sweep the volatiles fractions and provide the hydrogen for hydrogenation reactions. Any condensed fractions from the sweeping gas flows back with the oil bearing sands into section four for further cracking. The pre-set temperature in section three establishes the product boiling end point. All the oil fractions with a boiling point less than the temperature set point enter a cyclone arrangement  20  to remove solid particles and is immediately quenched at heat exchangers  83  and  85  to prevent overcracking before entering the product separator. The produced sour fuel gas is separated in vessel  87  and routed to fuel gas header  9  to provide the energy requirements for the process. The condensed liquid fractions are the product which is stabilized to ensure saturation of olefins present. The oil fractions with a boiling point greater than section three preset temperature, flow with the sand into section four. 
         [0016]    Section four,  4 , is the oil cracking section. This section, also has a bed immersed direct fired burner  24  and a serpentine duct distributed into three zone beds in a upwards countercurrent flow to the cascading oil bearing sands. Again, the bed level in each zone is controlled by longitudinal zone dividers  32 . The temperature in the last zone of the section is controlled by combusting fuel gas in the immersed direct fired burner  24 . The temperature in the other two upward zones are controlled by control valves  26  and  27 , the flue gases flow to each serpentine duct. The zone beds are fluidized by a distributed countercurrent flow  34  of product vapors generated in sections five, the solvent properties of product vapors enhance mass transfer, pre-heat the sands, sweep the volatiles fractions and provide the hydrogen for hydrogenation reactions in section four. Any condensed fractions from the sweeping gas flows back with the oil bearing sands into section five for further cracking. This mixture of cracked hydrocarbon vapors and sweep gas containing hydrogen rise to an upper catalytic zone  33  in section four, were vapour phase hydrogenation reactions occur. The hydrogenated vapour fractions leave the catalytic zone in section four as sweeping gas to section three distributor  19 . The cascading and cooler oil bearing sands stream in section three acts as a reflux stream to quench the exothermic temperature of the hydrogenated sweeping gas from section four to prevent overcracking. Any condensing fractions from the sweeping gas flows with the oil bearing sands back into section four for further cracking. The objective of section four is to control the cracking temperature in each zone to maximize liquid yields and minimize the formation of coke. The oil fractions with a boiling point greater than the preset temperature of section four flow with the sand into section five. 
         [0017]    Section five,  5 , is the coking section. This section, also has a bed immersed direct fired burner  37  and a serpentine duct  43  and  46  distributed into three zone beds in a upwards countercurrent flow to the cascading oil bearing sands. Again, the bed level in each zone is controlled by longitudinal zone dividers. The temperature in the last zone of the section is controlled by combusting fuel gas in the immersed direct fired burner  37 . The temperature in the other two upward zones are controlled by control valves  42  and  45 , the flue gases flow to each serpentine duct. The zone beds are fluidized by a distributed  37  countercurrent flow of product vapors generated in sections six, primarily hydrogen and carbon dioxide, sweeping the cracked volatiles fractions and providing the hydrogen for hydrogenation reactions. The oil fractions, primarily asphaltenes, are cracked at more severe operating conditions to produce vapors and coke. The mixture of cracked hydrocarbon vapors and sweep gas rise to an upper catalytic zone  38  in section five, were vapour phase hydrogenation reactions occur. The hydrogenated vapour fractions leave the catalytic zone in section five as sweeping gas to section four distributor  34 . The cascading and cooler oil bearing sands stream in section four acts as a reflux stream to quench the exothermic temperature of the hydrogenated sweeping gas to prevent overcracking. Any condensed fractions from the sweeping gas cascades with the oil bearing sands back into section five for further cracking. The section five operations temperature is set to meet coke production on demand. 
         [0018]    The production of coke is a prerequisite carbon source to meet the production of hydrogen in section six. The mixture of sand and coke cascades through duct  48  into section six, the hydrogen generation section. This section, also has bed immersed direct fired burners  54  and  63 , and serpentine ducts  57 ,  60 ,  67  and  70 , distributed into six zone beds in a upward countercurrent flow to the cascading coke bearing sands. Again, the bed level in each zone is controlled by longitudinal zone dividers. The temperature in two zones of the section is controlled by combusting fuel gas in the immersed direct fired burners  54  and  63 . The temperature in the other four upward zones are controlled by control valves  56 , 59 ,  65  and  69 , the flue gases flow to each serpentine duct. A distributed stream of superheated medium pressure steam  72  fluidizes the beds and provide the hydrogen and oxygen source to react with the coke to produce a syngas stream of hydrogen and carbon dioxide. The vapour mixture of steam, carbon monoxide, hydrogen and carbon dioxide rises to an upper catalytic zone  51  were water gas shift reactions are completed. The syngas produced leaves the catalytic zone in section six as sweeping gas to section five distributor  37 , providing the hydrogen for the process hydrogenation reactions. The temperature in section six is controlled by burners  54  and  63 , to generate on demand the hydrogen requirements for the process by reacting the coke in the sand with superheated steam to produce hydrogen and carbon dioxide. The very hot and oil free sand leaving section six through duct  74 , provide the thermal energy required to generate superheat steam in coil  72 . 
       Operation: 
       [0019]    Referring to  FIG. 1 , the cascading processor described above provides a process to recover and upgrade bitumen from oil sands. Oil sands have a typical composition 80-85% of sand and clay, 3-5% water and 10-15% bitumen, it is fed by stream  100  into deaeration column  1  where flue gases from stream  3  gives up its thermal energy to the mined oil sands to preheat and strip the air in the oil sands. The pre-heated and air stripped oil sands enters a downward sloped section  2  where the oil sands is further heated to temperatures greater than 100 C by an immersed heat transfer fluid coil  105 . The temperature in section  2  is controlled to evaporate all the water present in the oil sands, the vaporized stream exits through line  106 , cooled in cooling heat exchanger  75  and separated in separator  76 . The separated hydrocarbon gases are routed through line  93  into the fuel gas header  9 . The condensed and separated hydrocarbon liquids are routed through line  92  into Synthetic Crude Oil drum  87 . The condensed water is collected in boot  77  and routed through line  78  to pump  79 . The pressurized water stream is routed through line  80  to a membrane unit  81  to remove any dissolved solids that may be present. The cleaned water stream is generated into steam at heat exchanger  83  and routed through line  73  to a superheating steam coil  72 . The water free, oil sands cascade through the sloped section  2  into section  3 , where the temperature of the oil sands is increased in incremental steps through the three zones in section  3  to a maximum of 350 C. The section  3  has three zones, separated by longitudinal partitions  8 , at each zone the temperature is increased to control vaporization and minimize cracking. The partitions control the bed level in each zone. At the bottom of each bed zone a distribution gas header  19  provides fluidization and volatiles stripping to the oil sands. The oil sands first cascades into heat exchanger  17  zone where the oil sands are heated by the counter current flue gas exiting heat exchanger  14  into heat exchanger  17 . The temperature control into heat exchanger  17  is by flue gas temperature control valve  16 . The acid flue gases exiting; heat exchanger  17  and temperature control valve  16  and  13  are routed through line  18  into sulphur recovery plant  95 . The heated oil sands cascade from the sloped heat exchanger  17  zone into heat exchanger  14  zone where the temperature is further increased. The heat to heat exchanger  14  section is provided by the products of combustion of a bed immersed pulse burner heat exchanger  11 , the temperature control in this zone is provided by flue gas temperature control valve  13 . The oil sands temperature is further increased to a maximum of 350 C when it cascades into immersed pulse burner heat exchanger  11  zone. The temperature of the sand bed in pulse burner heat exchanger  11  is controlled by sour fuel gas control valve  10 . The hydrocarbon vapors in section  3  having a boiling point of lower than 350 C rise to the top of section  3 , are routed to cyclone  20  removing particulates trapped in the gaseous stream. The captured cyclone particulates are routed from the cyclone dip leg to pulse burner heat exchanger  11  zone sand bed. The gaseous product stream from cyclone  20  is routed to line  21 , cooled in heat exchanger  83 , through line  84  to trim cooler  85  and through line  86  into separator  87 . The condensed hydrocarbons are routed through line  88  to pump  89  and through line  90  to the stabilization unit. The generated sour gases are routed through line  91  into sour fuel gas header  9 . The oil sands now stripped of the hydrocarbon oil fractions with a boiling point of and less than 350 C cascade from the sloped section  3  into section  4  for further incremental heating. Section  4  also has three zones separated by longitudinal partitions  32 , at each zone temperature is increased to control vaporization and cracking. The partitions in each zone control the zone bed depth. A gas distribution header  34  distributes and fluidizes the oil sands bed zones in section  4  this gas mixture contains catalysed hydrocarbon vapors generated in section  5  and hydrogen generated in section  6 . The distribution gas also provides stripping for the volatiles generated in the bed zones of section  4  and the hydrogen required to meet hydrogen demand in catalytic zone  33 . The cascaded oil sands stream from section  3  enters heat exchanger  30  zone and is heated by the flue gases exiting heat exchanger  27 . The temperature in oil sands bed heat exchanger  30  section is controlled by flue gas temperature control valve  29 . The acid flue gas exits; heat exchanger  30  zone, acid flue gas temperature control valves  29  and  26 , to line  31  and onto sulphur recovery plant  95 . The oil sands cascade to heat exchanger  27  zone, are further heated by the flue gases leaving pulse burner heat exchanger  24  into heat exchanger  27 . The oil sands bed temperature in this zone is controlled by flue gas temperature control valve  26 . The oil sands cascades from heat exchanger  27  zone into pulse burner heat exchanger  24  zone to a maximum temperature of 450 C. The oil sands bed temperature in this section is controlled by fuel gas valve  23 . Cracking will commence in section  4  in the presence of nascent hydrogen and natural clays. The natural clays have catalytic properties and are a major component in the oil sands. The clay concentration in the oil sands can vary from 15 to 40% by wt. The objective in section  4  is to take advantage of the natural catalytic properties of the clays and in the presence of nascent hydrogen, hydrogenate the oil fractions as they are thermally cracked. The cascading cooler oil sands fractions provide a reflux stream behaviour to absorb the heat generated by the exothermix reactions. To further enhance and stabilize the cracked and rising vaporized oil fractions a channel catalytic zone  33  atop section  4  is provided. The catalytic processed vapors exit section  33  into gas distribution header  19  where it is cooled in a bed of cascading oil sands. The partially cracked oil sands stream cascades from section  4  into section  5  to complete the cracking process. Section  5  also has three zones separated by longitudinal partitions  36 , at each zone the temperature is increased to control vaporization and cracking. A gas distribution header  37  provides a gaseous stream of carbon dioxide and hydrogen to fluidize the oil sands bed in each zone and strip the volatiles generated in each zone. The hot oil sands stream cascades from sloped section  4  into section  5  heat exchanger  46  zone. The oil sands temperature is increased by the flue gas leaving heat exchanger  43  into heat exchanger  46 . The oil sands bed temperature in heat exchanger  46  zone is controlled by flue gas temperature control valve  45 . The acid flue gas exiting; heat exchanger  46  and temperature control valves  45  and  42  is routed to flue gas header  31  to sulphur recovery plant  95 . The oil sand stream cascades from heat exchanger  46  zone into heat exchanger zone  43 . The oil sands bed temperature in heat exchanger  43  zone is controlled by flue gas temperature control valve  42 . The oil sands cascades into pulse burner heat exchanger  40  zone which controls the operations temperature severity for the production of coke. The temperature in oil sands bed of pulse burner heat exchanger  40  zone is controlled by fuel gas valve  39 . The production of coke is controlled by the hydrogen requirements for hydrogenation reactions in the process. Coke and superheated steam are the reactants required to generate carbon dioxide and hydrogen in section  6 . The control of operation severity in section  5  is determined by coke production requirements. In section  5 , the remaining hydrocarbons in the oil sands stream are thermally cracked, in the presence of natural catalytic clays, hydrogen and carbon dioxide, rising to the top of section  6  into catalytic zone  38  for stabilization. The catalyzed vapors exit zone  38  into distribution header  34  in section  4 , were they are quenched by the cooler cascading oil sands. Some of the asphaltenes fraction of the bitumen in the oil sands are converted into coke in this section, the production of coke is controlled by temperature control of pulse burner heat exchanger  37  to meet the carbon source requirements to produce hydrogen in section  6 . The mixture of sand, clays and coke cascades through line  48  into section  6 , the hydrogen generation section. Section  6  has 6 zones separated by partitions  50 , at each zone the temperature is increased to control the gasification and water gas shift reactions to produce hydrogen and carbon dioxide. The zones are sloped to provide a continuous cascading flow of the solids through an increasing temperature range to ensure that all the coke present in the sand and clay mixture is converted through gasification and water gas shift reactions into hydrogen and carbon dioxide in the presence of superheated steam. The section has two pulse burners heat exchangers and four flue gas heat exchangers immersed in the sand and clay bed to provide the thermal energy required to convert the coke and superheated steam into hydrogen and carbon dioxide. The steam is supplied through line  73  and superheated in coil  72  by the thermal energy available in the processed sand and clay fractions exiting the section  6  through channel  74 . The superheated steam is distributed into all 6 bed zones to fluidized the beds and react with the coke generated in section  5  to form hydrogen and carbon dioxide. The gasification and water gas shift reactions are enthothermic, the energy required to control the temperature required for these reactions are provided by the combustion of sour gas controlled by temperature control valves  53  and  62  to bed immersed pulse burners  54  and  63  and associated flue gas heat exchangers  57 ,  60  and  67 ,  70  respectivelly. The mixture of hydrogen, carbon monoxide, carbon dioxide and steam vapors rise to the to the top of section  6  and passes through catalytic zone  51  to stabilize the carbon monoxide fractions into hydrogen and carbon dioxide. 
       Variations: 
       [0020]    Referring to  FIG. 2 , a variation is illustrated in which the arrangement of section  6  has a lower slope than  FIG. 1 . 
         [0021]    Referring to  FIG. 3 , a variation is illustrated in which the hydrogen and carbon dioxide generated in section  6  is routed through line  301 , cooled and separated in membrane  302 . The concentrated hydrogen stream  303  is compressed and routed through header  306  to section  5  for bed fluidization, stripping and hydrogenation reactions. 
         [0022]    Referring to  FIG. 4 , a variation is illustrated in which the hydrogen and carbon dioxide generated in section  6  is routed through line  301  cooled and separated in membrane  302 . The concentrated hydrogen is compressed to hydrogen header  306  for flow control distribution into sections;  5 , 4  and  3 , through valves  424 ,  426 , and  428 , providing better control of hydrogen addition to each section. Moreover,  FIG. 4  also provides the ability to process and produce a tailored product stream by controlling the products generated in sections  3 ,  4  and  5 . Each section vapour product is cooled and separated in a dedicated product stream loop. As an example, a portion of the higher boiling point vapour fractions of section  5  can be removed by flow control valve  413  through line  412 , cooled in heat exchanger  414  and  416 , and condensed in separator  418 . This process variation provides an option to meet various product slates. Any excess of higher boiling point fractions can be recycled through flow control valves  429  and  431  for further cracking. 
       Advantages: 
       [0023]    The above described approach provides a number of advantages:
       it eliminates the use of water as per the current practice in recovering bitumen from oil sands.   it eliminates or substantially reduces the use of an external fuel such as natural gas.   it eliminates the storage and containment of toxic water streams as per existing practices.   it eliminates the use of natural gas for the extraction of bitumen from tar sands.   the fuel gas generated in the process is used as the fuel source for the pulse heat exchanger, while recognizing that any other fuel can be employed.
 
As shown the process has a wide range for temperature requirements in each section. The temperature ranges demonstrated in  FIG. 1  are but a mode of operation selected for the example cited. These can vary according to feed composition and desired products.
       
 
         [0029]    The process as shown is not limited to its use in processing oil sands. It can also be employed to process, shale oil, biomass or any organic fuel derived matter. When the processor is employed to process biomass, there is the option of employing a fixed bed height from inert materials such as sand, whereas the biomass cascades over the partitions as an overflow into each zone versus the mode of operation in the oil sands processor where the partition controls an underflow into each zone. The processor is particularly suitable to handle any solids and extract its organic matter as fuels over a wide range of operations conditions. 
         [0030]    In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. 
         [0031]    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.