An improved configuration of method and apparatus for recovering oil from solid hydrocarbonaceous material

Description

[0001] This invention relates to an improved configuration of method and apparatus for recovering oil form solid hydrocarbonaceous material and has been devised particularly though not solely for the utilisation of the excess residual carbon in oil shale after the extraction of oil vapours.

[0002] Many processes have been proposed for the recovery of oil from solid hydrocarbonaceous material such as oil shale or coal, but many of these methods are not suitable due to the low utilisation of energy and therefore the high cost of extracting the oil. One form of oil recovery from solid hydrocarbonaceous material is described in our co-pending Australian Patent Application 20678/83 where with reference to Figure 2 it can be seen that an attempt has been made to recover the maximum amount of energy by the incorporation of steam coils 36 into the transport combustor 29. Incorporation of such coils increases the pressure drop in the transport combustor requiring a high capacity air blower 31 which increases the capical expense and the operating cost of the plant. Furthermore the burning of substantially all of the residual carbon in the oil shale in the transport combustor 29 to achieve a high plant efficiency, results in problems of control of heating the heat medium shale to the required temperature for the reaction in the retort 20.

[0003] It is therefore an object of the present invention to provide a method of and apparatus for recovering oil from solid hydrocarbonaceous material which is inherently efficient and which will obviate or minimise the foregoing disadvantages in a simple yet effective manner, or which will at least provide the public with a useful choice.

[0004] Accordingly in one aspect the invention may broadly be said to consist in a method of recovering oil from solid hydrocarbonaceous material comprising the steps of:-

contacting fresh feed hydrocarbonaceous material particles with heat medium particles in a dense phase fluidised bed, with the fluidising medium for the bed being generated within the bed and being constituted at least primarily by fluid released by conversion of kerogen in the feed material,

withdrawing from the bed oil vapour which is produced as a result of heat exchange between the heat medium particles and the feed particles,

progressively withdrawing the heat medium particles and spent feed material particles from the fluidised bed,

heating the heat medium particles in a heating region external of the fluidised bed by burning residual carbon therein at a controlled rate sufficient to provide the heat needed for the said heat exchange,

recirculating the necessary volume of heated particles through the fluidising bed with fresh feed material particles,

withdrawing heat medium particles which are surplus to the said necessary volume of heated particles, and

reheating the withdrawn heat medium particles by burning the residual carbon therein to provide additional usable heat.

[0005] Preferably the additional usable heat is used to generate steam for use in the oil recovery process or in other processes.

[0006] Preferably the withdrawn heat medium particles are reheated in a transport combustor by providing the required volume of air under pressure.

[0007] Preferably the transport combustor incorporates steam generation pipes or coils.

[0008] In a further aspect the invention may broadly be said to consist in apparatus for recovering shale oil from oil shale, said apparatus comprising a retort adapted to contain a dense phase fluidised bed, a combustor arranged to receive spent feed shale and recirculating heat medium shale from said retort and to combust a portion of the residual carbon therein in the presence of a combustion supporting gas at a controlled rate, flow control means arranged to return controlled amounts of recirculated heat medium shale from said combustor to said retort, feed means adapted to feed fresh feed shale particles into said retort, extraction means adapted to extract shale oil vapour from said retort, and secondary combustion means arranged to receive the heat medium shale not returned to the retort, and to combust the remaining residual carbon thereon to provide additional usable heat.

[0009] Preferably the secondary combustion means comprise a transport combustor provided with air under pressure at a sufficient rate to combust the remaining residual carbon.

[0010] Preferably said transport combustor incorporates pipes or coils for the generation of steam.

[0011] In a still further aspect the invention may broadly be said to consist in apparatus for utilising excess residual carbon remaining in solid hydrocarbonaceous material after oil vapour recovery therefrom, said apparatus comprising a transport combustor to which the solid hydrocarbonaceous material is fed, air supply means arranged to supply air to the combustor to burn the residual carbon in the solid hydrocarbonaceous material, and steam generation means within the transport combustor.

[0012] Notwithstanding any other forms that may fall within its scope, one preferred form of the invention will now be described by way of example only with reference to the accompanying drawing which is a schematic representation of a shale oil recovery plant incorporating the features of the present invention.

[0013] The shale oil recovery plant shown in the accompanying drawing is a modification of the shale oil recovery plant described and illustrated with reference to Figure 2 of our co-pending Australian Patent Application 20678/83.

[0014] The shale oil recovery plant comprises a retort 20 into which fresh particulate feed shale is delivered, by way of a feed line 21 from a surge bed 22 controlled by an inlet valve 43.

[0015] Recirculating heat medium shale is also delivered to the retort 20 at a controlled rate, the heat medium shale being supplied by a feed line 23 and a control valve 44 from a dense phase fluidised surge bed which is contained within a vessel 24. The heat medium shale is delivered to the retort 20 in sufficient quantity to effect the retort temperature and holding time conditions sufficient to convert the kerogen content of the feed shale into gas and oil vapour products which are released at all levels throughout the bed of particulate material within the retort 20 and thus a fluidised bed is created without there being the need to inject a fluidising medium from an external source.

[0016] Gas and oil vapour which migrates above the fluidised bed in the retort 20 is drawn from the retort by way of a cyclone separator 25 and is delivered- to a product fractionating system (not shown) by way of a feed line 47 for subsequent processing to final or transportable products.

[0017] Spent feed shale and recirculating heat medium shale progressively passes from the fluidised bed within the retort 20 and enters a stripping vessel 26 by way of a feed line 27 incorporating a control valve 45. Residual gas and oil vapour which is entrained in the particles progress into the stripping vessel 26, are stripped from the particles by gas or steam which is injected into the stripping vessel, and the resulting gas and oil vapours are directed into an upper region of the retort 20 by way of a delivery line 28.

[0018] The stripped spent shale and recirculating heat medium shale are thereafter passed from the stripping vessel 26 to a dilute phase transport combustor 29 by way of a valved feed line 30.

[0019] The transport combustor 29 is constituted by a dilute phase burner into which the recirculated heat medium and spent feed shale is directed and in which residual carbon on or in the spent shale is burned in the presence of combustion supporting air. Thus, in contrast with the dense phase fluidised bed which is established within the retort 20, the transport combustor 29 functions as a dilute phase device into which fluidising air is directed by a blower 31.

[0020] Air from the blower 31 is admitted to the lower region of the transport combustor 29 by way of a controlled delivery line 32 and the air entrains the spent feed shale and the recirculating heat medium shale from the stripping vessel and carries the shale particles along the length of the transport combustor 29. During the particle residence time in combustor 29, the residual carbon on and in the shale is burnt in the presence of the entraining air, and the heat of combustion raises the temperature of the particles to the level required to effect the fluidised bed retorting in the retort 20. When the spent shale particles enter the transport combustor and are elevated in temperature, such particles may be regarded as being recirculating heat medium shale because they are thereafter directed, at an elevated temperature, into the surge bed vessel 24 and into the retort 20 together with previously recirculated heat medium shale.

[0021] Having passed through the transport combustor 29 the recirculating heat medium particles and the entrained gas are delivered to a cyclone 33 which functions to separate the solid particles from the gas. The entraining gas and air which exits from the surge bed 24 is expelled as flue gas and the solid particles are directed into the surge bed 24 for subsequent transfer into the retort vessel 20. The surge bed 24 is conveniently fluidised by way of air from the blower 31 via the controlled air inlet line 35.

[0022] Obviously as fresh feed shale is fed into the system from the surge bed 24 it is necessary to withdraw the excess recirculating heat medium shale to maintain a constant level of particles within the process. The excess heat medium shale is withdrawn via a delivery line 34 from the surge bed 24 controlled by control valve 100.

[0023] The excess heat medium shale is then delivered to the lower end of a transport combustor 101 which is provided with air through air supply line 102 from a low pressure air blower 103 controlled by control valve 104. The transport combustor 101 is similar in operation to the combustor 29 described above but incorporates steam generation pipes or coils 105.

[0024] The remaining residual carbon in the shale delivered to the transport combustor 101 is combusted by the air delivered through the line 102 giving off further heat to generate steam within the pipes or coils 105. The steam pipes or coils 105 are connected in circuit with a source 37 of water and function to generate steam for use in the oil recovery plant or in associated equipment.

[0025] By way of contrast with the plant described with reference to Figure 2 of our co-pending Australian Patent Application 20678/83 the steam is generated in a separate transport combustor 101 rather than by way of steam generation pipes or coils incorporated in the main transport combustor 29. The control of the primary combustor 29 is simplified by not having to also control the amount of steam generated therein. As the carbon residue percentage on solids is higher, reaction rates and utilisation of combustion air are both improved. There is little requirement for excess air to accomplish the desired heating of the heat medium shale and this helps to make control in the transport combustor 29 more precise. The heat of the recirculated heat medium shale issuing from the transport combustor 29 may be accurately controlled by controlling the amount of residual carbon burnt by the control of the air from the blower 31. As only a portion of the residual carbon is burnt in the transport combustor 29 a lower capacity air blower may be utilised compared with that shown in our earlier patent application with a consequent saving in both capital and operating costs.

[0026] The hot spent shale from the circulating shale surge vessel 24 flows down a dense phase stand pipe 34 through a throttling control valve 100 to enter the dilute phase combustion riser 101. Combustion air enters the same riser at a level slightly below the solids entry, carrying them up in a dilute phase flow while burning the remaining residual carbon within the shale to release heat. This heat is radiated to the steam tubes 105 positioned on the riser walls generating steam for use elsewhere. The combustion air amount may be accurately controlled to match the amount of carbon available in the shale or, alternatively, the amount of steam which the plant can profitably utilise.

[0027] Gas velocity in the riser 101 may reasonably vary over a range of about 15 to 75 feet per second (4.6-22.9 m/sec) allowing good flexibility in the amount of carbon that can be burnt. Flue gas and shale solids are separated in cyclones (not shown) at the top of the riser.

[0028] In this manner a plant for the extraction of oil vapour from solid hydrocarbonaceous material may be provided with the following advantages.

[0029] Burning only part of the available carbon residue in the primary combustor 29 improves the oxygen-carbon reaction rate and lowers or essentially eliminates the amount of unreacted, "excess", oxygen in the exit flue gas streams.

[0030] Removing the steam generation surface and heat load from the primary combustor simplifies control of the circulating shale temperature. The amount of air injected into the combustor directly sets the outlet temperature and this can be readily adjusted as needed. There is no conflicting requirement to also control the amount of heat used to generate steam. If steam is generated in the primary combustor, control of that heat absorbtion must be by the amount of steam tube surface provided and by the operating pressure and temperature of the steam boiler system. Each of these controls is mainly determined by the original plant design and allows relatively little flexibility in operation. The result finally is that control of hot circulating solids temperatures and the required flow rates to the retort will be less stable and can adversely affect product yield and properties.

[0031] Burning the remaining carbon residue in a secondary combustor is conducted only for the purpose of recovering the carbon fuel values to the extent that this is economically feasible. The amount of carbon burnt is directly related to the amount of oxygen (air) injected. Regulation of this flow provides a single and effective variable for control of the combustor. If carbon removal of a very low level is required, say 0.05 weight percent on discarded shale, an appreciable amount of excess oxygen may be present in the flue gas from the secondary combustor 101. A typical range might be 0.5 to 3 percent. If both process heat and steam generation heat are provided by the same combustor, then a comparable percentage of excess air will be required for the total air supply.- Depending upon specific plant requirements, having separate primary and secondary combustors permits a lower operating pressure for a substantial part of the combustion air and a consequent saving in compression horse power. The investment and operating costs for air compressors and related apparatus is a significant factor for shale plants employing residual carbon combustion.

Claims

1. A method of recovering oil from solid hydrocarbonaceous material comprising the steps of:-

contacting fresh feed hydrocarbonaceous material particles with heat medium particles in a dense phase fluidised bed (20), with the fluidising medium for the bed being generated within the bed and being constituted at least primarily by fluid released by conversion of kerogen in'the feed material,

withdrawing from the bed oil vapour which is produced as a result of heat exchange between the heat medium particles and the feed particles,

progressively withdrawing the heat medium particles and spent feed material particles from the fluidised bed,

heating the heat medium particles in a heating region (29) external of the fluidised bed by burning residual carbon therein at a controlled rate sufficient to provide the heat needed for the said heat exchange,

recirculating the necessary volume of heated particles through the fluidising bed with fresh feed material particles,

withdrawing heat medium particles which are surplus to the said necessary volume of heated particles, and

reheating the withdrawn heat medium particles by burning the residual carbon therein to provide additional usable heat.

2. A method as claimed in claim 1 wherein the additional usable heat is used to generate steam for use in the oil recovery process or in other processes.

3. A method as claimed in claim 1 wherein the withdrawn heat medium particles are reheated in a transport combustor (101) by providing the required volume of air under pressure.

4. A method as claimed in claim 3 wherein the transport combustor incorporates steam generation pipes or coils (105).

5. Apparatus for recovering shale oil from oil shale, said apparatus comprising a retort (20) adapted to contain a dense phase fluidised bed, a combustor (29) arranged to receive spent feed shale and recirculating heat medium shale from said retort and to combust a portion of the residual carbon therein in the presence of a combustion supporting gas at a controlled rate, flow control means (44) arranged to return controlled amounts of recirculated heat medium shale from said combustor to said retort, feed means (27) adapted to feed fresh feed shale particles into said retort, and extraction means (25) adapted to extract shale oil vapour from said retort, characterised by the provision of secondary combustion means (101) arranged to receive the heat medium shale not returned to the retort, and to combust the remaining residual carbon thereon to provide additional usable heat.

6. Apparatus as claimed in claim 5 wherein the secondary combustion means comprise a transport combustor (101) provided with air under pressure at a sufficient rate to combust the remaining residual carbon.

7. Apparatus as claimed in claim 6 wherein said transport combustor incorporates pipes or coils (105) for the generation of steam.

8. Apparatus for utilising excess residual carbon remaining in solid hydrocarbonaceous material after oil vapour recovery therefrom, characterised by the provision of a transport combustor (101) to which the solid hydrocarbonaceous material is fed, air supply means (102) arranged to supply air to the combustor to burn the residual carbon in the solid hydrocarbonaceous material, and steam generation means (105) within the transport combustor.

Ansprüche

1. Verfahren zum Zurückgewinnen von Öl aus festem kohlenwasserstoffhaltigen Material, das die Schritte aufweist:

frische kohlenwasserstoffhaltige Speisematerialpartikel mit Wärmemediumpartikeln in einem fluidisierten Bett (20) dichter Phase in Berührung zu bringen, wobei das fluidisierende Medium für das Bett innerhalb des Betts erzeugt wird und wenigstens hauptsächlich durch Fluid gebildet wird, das durch Umwandlung von Kerogen im Speisematerial frei wird,

aus dem Bett Öldampf abzuziehen, der als Ergebnis von Wärmeaustausch zwischen den Wärmemediumpartikeln und den Speisepartikeln erzeugt wird,

fortschreitend die Wärmemediumpartikel und verausgabten Speisematerialpartikel aus dem fluidisierten Bett abzuziehen,

die Wärmemediumpartikel in einem Heizbereich (29) außerhalb des fluidisierten Betts durch Verbrennen von darin enthaltenem restlichen Kohlenstoff mit kontrollierter Geschwindigkeit zu erhitzten, die ausreicht, die für den Wärmeaustausch notwendige Wärme zur Verfügung zu stellen, das notwendige Volumen von erhitzten Partikeln durch das fluidisierende Bett mit frischen Speisematerialpartikeln im Kreislauf zurückzuführen,

Wärmemediumteilchen abzuziehen, die in bezug auf das notwendige Volumen erhitzter Partikel überflüssig sind, und

die abgezogenen Wärmemediumpartikel durch Verbrennen des darin enthaltenen restlichen Kohlenstoffs wieder zu erhitzten, um zusätzliche nutzbare Wärme zu schaffen.

2. Verfahren nach Anspruch 1, bei dem die zusätzliche nutzbare Wärme zum Erzeugen von Dampf benutzt wird, der beim Ölzurückgewinnungsverfahren oder anderen Verfahren verwendbar ist.

3. Verfahren nach Anspruch 1, bei dem die abgezogenen Wärmemediumpartikel in einer Transportverbrennungskammer (101) wieder erhitzt werden, indem das notwendige Luftvolumen unter Druck zugeführt wird.

4. Verfahren nach Anspruch 3, bei dem die Transportverbrennungskammer Dampferzeugungsrohre oder Schlangen oder Spiralen (105) aufweist.

5. Vorrichtung zum Zurückgewinnen von Schieferöl aus Ölschiefer, wobei die Vorrichtung eine Retorte (20), die ein fluidisiertes Bett dichter Phase enthalten kann, eine Verbrennungskammer (29), die zum Aufnehmen von verausgabtem Speiseschiefer und zum Zurückführen von Wärmemediumschiefer im Kreislauf von der Retorte und zum Verbrennen eines Teils des darin enthaltenen restlichen Kohlenstoffs in Anwesenheit eines die Verbrennung unterstützenden Gases bei einer kontrollierten Geschwindigkeit ausgebildet ist, Strömungssteuermittel (40), die zum Zurückführen kontrollierter Mengen von im Kreislauf zurückgeführtem Wärmemediumschiefer von der Verbrennungskammer zur der Retorte ausgebildet sind, Speisemittel (21), die zum Zuführen von frischen Speiseschieferpartikeln in die Retorte ausgebildet sind, und Extraktionsmittel (25) aufweist, die zum Abziehen von Schieferöldampf aus der Retorte ausgebildet sind, dadurch gekennzeichnet, daß sekundäre Verbrennungsmittel (101) vorgesehen sind, die zum Aufnehmen des nicht zur Retorte zurückgeführten Wärmemediumschiefers und zum Verbrennen des daraus verbliebenden restlichen Kohlenstoffs ausgebildet sind, um zusätzliche nutzbare Wärme zu schaffen.

6. Vorrichtung nach Anspruch 5, bei dem die Sekundärverbrennungsmittel eine Transportverbrennungskammer (101) aufweisen, die mit Druckluft mit ausreichender Geschwindigkeit versorgt wird, um den verbleibenden restlichen Kohlenstoff zu verbrennen.

7. Vorrichtung nach Anspruch 6, bei dem die Transportverbrennungskammer Rohre oder Schlangen oder Spiralen (105) für die Erzeugung von Dampf aufweisen.

8. Vorrichtung zum Verwenden von überschüssigem restlichen Kohlenstoff, der in festem kohlenwasserstoffhaltigem Material nach Rückgewinnung von Öldampf aus demselben zurückbleibt, dadurch gekennzeichnet, daß eine Transportverbrennungskammer (101), der das feste kohlenwasserstoffhaltige Material zugeführt wird, Luftspeisemittel (102), die zum Zuführen von Luft zur Vebrennungskammer zum Verbrennen des restlichen Kohlenstoffs im festen kohlenwasserstoffhaltigen Material vorgesehen sind, und Dampferzeugungsmittel (105) innerhalb der Transportverbrennungskammer vorgesehen sind.

Revendications

1. Procède de récupération de pétrole à partir d'une matière hydrocarbonée solide, comprenant les étapes consistant à: mettre en contact des particules de matière hydrocarbonée fraîches avec des particules de milieu thermique dans un lit fluidisé à phase dense (20), le milieu de fluidisation pour le lit étant créé à l'intérieur du lit et étant constitué au moins principalement par le fluide libéré par la conversion du kérogène dans la matière hydrocarbonée,

retirer du lit la vapeur de pétrole qui est produite en conséquence de l'échange thermique entre les particules de milieu thermique et les particules de matière hydrocarbonée,

retirer progressivement les particules de milieu thermique et les particules de matière hydrocarbonée épuisées du lit fluidisé,

chauffer les particules de milieu thermique dans une région de chauffage (29) externe au lit fluidisé en y brûlant le carbone résiduel à un taux contrôlé suffisant pour fournir la chaleur nécessaire pour ledit échange thermique,

faire recirculer le volume nécessaire de particules chauffées à travers le lit fluidisé avec des particules de matière hydrocarbonée fraîches, retirer les particules de milieu thermique qui sont en surplus par rapport audit volume nécessaire de particules chauffées, et

rechauffer les particules de milieu thermique retirées en y brûlant le carbone résiduel pour fournir de la chaleur utilisable supplémentaire.

2. Procédé selon la revendication 1, dans lequel la chaleur utilisable supplémentaire est utilisée pour créer de la vapeur utilisable dans le procédé de récupération de pétrole ou dans d'autres procédés.

3. Procédé selon la revendication 1, dans lequel les particules de milieu thermique retirées sont rechauffées dans un appareil de combustion de transport (101) en fournissant le volume nécessaire d'air sous pression.

4. Procédé selon la revendication 3, dans lequel l'appareil de combustion comporte des conduits ou serpentins de création de vapeur (105).

5. Appareil pour récupérer du pétrole de schiste bitumineux, ledit appareil comprenant une cornue (20) adaptée pour contenir un lit fluidisé à phase dense, un appareil de combustion (29) agencé pour recevoir le schiste d'alimentation épuisé et le schiste de milieu thermique recircu- lant à partir de ladite cornue et y brûler une partie du carbone résiduel en présence d'un gaz comburant à un taux contrôlé, des moyens de commande de flux (44) agencés pour faire retourner des quantités commandées de schiste de milieu thermique recirculé dudit appareil de combustion à ladite cornue, des moyens d'alimentation (21) adaptés pour fournir des particules de schiste fraiîches dans ladite cornue, et des moyens d'extraction (25) adaptés pour extraire de la vapeur de pétrole de ladite cornue, caractérisé en ce qu'il comprend des moyens de combustion secondaires (101) agencés pour recevoir le schiste de milieu thermique non retourné à la cornue et y brûler le carbone résiduel restant pour fournir de la chaleur utilisable supplémentaire.

6. Appareil selon la revendication 5, dans lequel les moyens de combustion secondaires comprennent un appareil de combustion de transport (101) alimenté en air sous pression à un taux suffisant pour brúler le carbone résiduel restant.

7. Appareil selon la revendication 6, dans lequel ledit appareil de combustion comporte des conduits ou serpentins (105) pour la création de vapeur.

8. Appareil pour utiliser le carbone résiduel en excès restant dans de la matière hydrocarbonée solide après que de la vapeur de pétrole en a été récupérée, caractérisé en ce qu'il comporte un appareil de combustion de transport (101) auquel est fournie la matière hydrocarbonée solide, des moyens d'alimentation d'air (102) agencés pour fournir de l'air à l'appareil de combustion pour brûler le carbone résiduel dans la matière hydrocarbonée solide, et des moyens de création de vapeur (105) à l'intérieur de l'appareil de combustion.

Drawing