NL2007435C2

NL2007435C2 - Vertical tube reactor for the processing of oil sands and a method of processing oil sands.

Info

Publication number: NL2007435C2
Application number: NL2007435A
Authority: NL
Inventors: Kees-Jan Leendert Rijnsburger; Paulus Carolus Marie Knops
Original assignee: Rijnsburger Holding B V; Plan B Co2 B V
Priority date: 2011-09-16
Filing date: 2011-09-16
Publication date: 2013-03-19
Also published as: WO2013039399A1

Abstract

Vertical tube reactor (1) for the processing of oil sands, comprising: . a downward tube section and a upward tube section which are fluidly connected with each other at the bottom of the tube reactor, . the downward tube section comprising a feed tube (3) for the trans port of oil sands, the upward tube section comprising a first exit tube (5) and a second exit tube (7), . whereby a cyclone (12) is provided at the bottom of the tube reactor, wherein the cyclone has an inlet (14) and two outlets defined as an overflow (16) and an underflow (18) respectively, said inlet (14) being fluidly connected to the feed tube (3), and the overflow being fluidly connected to the first exit tube (5) and the underflow being fluidly connected to the second exit tube (7). Method of processing oil sands using the vertical tube reactor according to the invention.

Description

Vertical tube reactor for the processing of oil sands and a method of processing oil sands 5 The present invention relates to a vertical tube reactor for the processing of oil sands and a method of processing oil sands using such a reactor.

Oil sands, also known as oil shale, bituminous sands or tar sands, are natural petroleum deposits in the earth. Oil 10 sands can be recovered by mining techniques. Oil sands that are recovered consist of a mixture of sand, clay, water and a highly viscous petroleum fraction, generally referred to as bitumen or tar. The bitumen fraction is usually in a semi-solid phase when recovered. Oil sands have recently 15 become a viable and therefore interesting alternative source for petroleum products.

In the context of the present invention, the processing of oil sands comprises the separation of bitumen from the other constituents of oil sands (i.e. so-called residues), 20 as well as the treatment of the separated bitumen so that it is converted into 'lighter' petroleum products that have a lowered viscosity and have a reduced specific density. Both processing steps are presently performed in a sequential manner, using two different installations: one installation 25 in which the separation step is performed, and one installation for the treatment of bitumen such as a thermal cracking reactor or an oxidation reactor. In addition, it is often required to treat the residual fraction of oil sands to ensure the residues are free of bituminous 30 contaminations.

Although the above type of sequential processing of oil sands is commonly used, it requires the input of a relatively large amount of energy. In this respect, the 2 present way of processing oil sands can thus be improved in order to satisfy the general need to reduce overall energy consumption in industry.

The present invention is aimed at presenting a 5 different way of processing oil sands so that energy consumption is reduced, while a residual fraction is produced having a lower content of contaminants. To achieve that goal, a special type of reactor is developed which allows the combined performance of the separation of bitumen 10 as well as the conversion of bitumen into lighter petroleum products .

In a first aspect, the invention relates to a vertical tube reactor for the processing of oil sands, comprising: a downward tube section and a upward tube section which are 15 fluidly connected with each other at the bottom of the tube reactor, the downward tube section comprising a feed tube for the transport of oil sands, the upward tube section comprising a first exit tube and a 20 second exit tube, characterized in that a cyclone is provided at the bottom of the tube reactor, wherein the cyclone has an inlet and two outlets defined as an overflow and an underflow respectively, said inlet being fluidly connected to the feed 25 tube, and the overflow being fluidly connected to the first exit tube and the underflow being fluidly connected to the second exit tube.

Typically, such a vertical tube reactor is suitable for exchanging heat between the upward tube section and the 30 downward tube section because of its design. The design of the tube reactor implies the upward tube section and the downward tube section to be neighbouring to each other, so that an efficient heat exchange is possible through the 3 respective walls that separate both tube sections from another .

When the vertical tube reactor is used, a high temperature and pressure is maintained in the first exit 5 tube through which bituminous material is transported, in order to perform a conversion reaction of the bituminous material under optimum conditions. Consequently, a stream with a raised temperature is led through the upward section. The heated stream through the upward section is capable to 10 exchange heat with the neighbouring downward tube section, through which the feed of oil sands with relatively low temperature is led. Thus the feed stream of oil sands that is led through the feed tube, is automatically heated by the neighbouring upward tube section.

15 When the feed stream having a raised temperature reaches the cyclone inlet, the oil sands are easier separated: the raised temperature of the oil sands lowers the viscosity of the bitumen fraction, which promotes its separation in a cyclone from the other constituents. In 20 addition, the raised temperature increases the density difference between the bitumen fraction and the fraction of residues, so that the separation is further enhanced. Thus, the separation efficiency of the cyclone is highly raised, in comparison to known separation processes.

25 Effectively, the overflow outlet of the cyclone contains the lighter separated fraction, which contains a high content of bitumen and/or hydrocarbons derived from bitumen. Subsequently, the lighter separated fraction is led through the first exit tube upwards. During the passage 30 through the first exit tube, the raised temperature will promote a conversion reaction wherein the bitumen components and hydrocarbons derived from bitumen are converted into hydrocarbons which have a reduced viscosity and density.

4

This conversion reaction may be further supported by the introduction of oxygen gas, as will be set out below.

At the underflow outlet of the cyclone, a stream is obtained which contains the heavier separated section, which 5 comprises a high content of water, sand and minerals.

Because of the raised efficiency of the cyclone, this stream will contain less bitumen as a contaminant.

In summary, an improved separation of bitumen is obtained from the other constituents from oil sands, which 10 results in a exit stream from the first exit tube which contains hydrocarbons with reduced viscosity and density, having less contamination from the other three heavier components. At the same time, the stream of product from the second exit tube, which is regarded as waste, contains less 15 bitumen, so that less valuable product is lost. Furthermore, the heat exchange between the downward and upward tube sections of the reactors is optimum to achieve this advantageous effect. Finally, the tube reactor provides an elegant and integrated reactor design in order to solve the 20 above stated problems.

In the context of the invention, the term 'fluidly connected' is used to express that two tubes or conduits are connected in such a way that a fluid can be conveyed from one entity to the other.

25 Advantageously, pressure valves are applied at the connection between the feed valve and the cyclone, in order to control the pressure inside the cyclone to an optimum operational pressure value.

30 Preferably, the vertical tube reactor according to the invention is vertically positioned in the ground and for the main part extends into the ground, the tube reactor having an overall length between 500 and 1500 m. In this way, the 5 optimum circumstances are achievable in regard of heat conservation, and raised pressure at the bottom of the reactor.

5 With further preference, the vertical tube reactor according to the invention, contains a cyclone which is a hydrocyclone suitable for the separation of a liquid suspension into two fractions. Such a cyclone proved most effective for the separation of bitumen from oil sands.

10

In another preferred embodiment, the vertical tube reactor comprises between the underflow and the second exit tube and fluidly connected to both, a reservoir for the accumulation of solid particles. The reservoir allows and 15 promotes the precipitation of solid particles from the underflow stream. As such the reservoir promotes the separation of solid residues, while a stream of water and traces of bitumen and their derivatives which is effectively free of solids, is led upwards through the second exit tube.

20

Preferably, the upward section of the vertical tube reactor comprises a third exit tube for transportation of solid particles. Accordingly, a separate, third exit stream of solids is produced by the reactor, separate from the 25 second and first exit streams. The solids may be treated as waste or be further subjected to any desired processing.

With special preference, the vertical tube reactor according to the invention comprises conduits for gas 30 injection which are provided in the first, the second, and/or the third exit tube. Such conduits are suitable for introducing oxidizing agents, such as oxygen gas into the respective exit tubes.

6

Especially in the first exit tube, the introduction of oxygen in the product stream is very effective in further promoting the conversion reaction of bitumen and hydrocarbons derived from bitumen into hydrocarbons which 5 have a reduced viscosity and density. The degree of conversion can be controlled according to the desires of the user. The further promoting of the conversion reaction may contribute to more heat being formed, which is exchanged with the incoming feed stream, and thus further raises the 10 separation efficiency of the cyclone.

The introduction of oxygen in the second exit tube will be helpful to convert any bitumen that is sticking on the mineral solids as contamination. Thus the yield of bitumen or hydrocarbons derived from bitumen can be raised in the 15 fluid part of the second exit stream. This will also result in the solids (when these are eventually separated from the second exit stream) to be low in contamination by petroleum components. Because such solids have a reduced content of contaminating hydrocarbon material, they can be further 20 treated using a biological polishing filter, without the risk of damaging the biological functionalities.

In contrast to the present invention, the processes from the prior art produce a residual fraction which is hard to dispose of because it includes contaminating bituminous 25 material that is very persistent and for is not easily separated from the residues.

In case the solids still contain a high content of petroleum components, these solids can separately be transported through a third exit tube into which oxygen is 30 injected.

An additional advantageous effect of introducing oxygen in any of the exit tubes - and especially in the second exit 7 tube - is that C02 will be formed which will be converted in the aqueous stream into dissolved bicarbonate. The dissolved bicarbonate will react with calcium species present in the stream, so that calcite is formed, which will precipitate 5 relatively quickly from the stream. Therefore, the formation of C02 will eventually raise the rate of precipitation of solids in the underflow stream. Furthermore, the formation of calcite will raise the specific density of the solid residues. This effect further contributes to the overall 10 separation efficiency, when separating solid residues from the aqueous stream. This advantageous effect still persists when the solid residues are obtained from the third exit tube, and are subjected to a final purification step wherein water is removed.

15 Preferably, the vertical tube reactor of the invention further comprises a separate tube section for heat exchange with the upward and/or downward tube sections. Such a heat exchange is advantageous during start-up of the processing, in order to heat the initial feed of oil sands. Conversely, 20 a heat exchange with the upward tube section may be advantageous to further recover any excess heat from the upward tube section that is not needed to heat the feed of oil sands.

25 In another embodiment of the vertical tube reactor according to invention, the cyclone is present in a cyclone unit that forms a releasable part of the tube reactor, and which cyclone unit can readily be assembled at the intended position within the tube reactor. As such, the cyclone part 30 can be expediently be taken apart from the reactor, in case of maintenance or failure of the cyclone.

8

In a further embodiment of the vertical tube reactor according to the invention, the tube reactor is provided with more than one cyclone at the bottom of the tube reactor. As such, the separation capacity of the tube 5 reactor is enhanced. The multitude of cyclone units may be positioned in a parallel or sequential order. Each cyclone unit may further be provided with independent entry and exit valves. As such, one cyclone may be shut down while another is in use, so that a continuity of processing is secured.

10

In a second aspect, the invention relates to a method of processing oil sands using the vertical tube reactor according to the invention, wherein the method comprises the steps of: 15 - introducing a slurry of oil sands into the feed tube and subsequent downward transport of the slurry towards the cyclone, wherein the slurry basically comprises a mixture of water, sand, minerals and bitumen; separating the slurry of oil sands into two fractions 20 by virtue of the cyclone, so that an overflow fraction is obtained which comprises a high content of bitumen component and/or hydrocarbons derived from bitumen, and an underflow fraction is obtained which comprises a high content of water, sand and minerals; 25 - leading the overflow fraction via the overflow outlet of the cyclone, through the first exit tube of the tube reactor; leading the underflow fraction via the underflow outlet of the cyclone, through the second exit tube of the tube 30 reactor.

The main advantages of such a method are already explained above, and basically relate to the separation 9 being improved, while securing a reduction in energy consumption of the process.

In addition, it is noted that during the transport through the feed tube, the slurry particles of the oil sands 5 are subjected to high shearing forces, so that solid particles present in the slurry are eroded concomitantly. Consequently, the method allows to process oil sands containing particles of a relatively large diameter, without the need of subjection the particles to any additional 10 treatment to reduce the mean particle size in order to achieve a sufficient yield of bitumen.

Further, any traces of sulphur in the oil sands, will be oxidized to S04 which is easily separated from the fluid streams, by precipitation of S04 in solid from.

15 Consequently, the process achieves an easy reduction of the sulphur content of the petroleum products obtained.

It is preferred that the method of the invention further comprises the step of: 20 - introducing oxidizing agent, preferably oxygen gas, via conduits for gas injection in the first, the second, and/or the third exit tube.

The related advantages are already explained above in view of the reactor of the invention.

25

Another preferred method of the invention, further comprises the step of: accumulating solid particles from the underflow fraction in a reservoir positioned between the underflow and 30 the second exit tube which is fluidly connected to both, and preferably the step of transporting the solid particles through a third exit tube. This step allows for dividing the yield of the processing method into three separate streams.

10

Preferably, the method according to the invention, further comprises the step of: exchanging heat between the upward and downward tube sections by heat exchange, preferably using in addition a 5 separate tube section inside the tube reactor for heat exchange. As such, the efficiency of energy consumption of the method is further raised.

Example 10

The design of the vertical tube reactor and its use is further explained below, with reference to the appended figure 1 which shows a cross-section of a preferred embodiment of the vertical tube reactor in use.

15

In figure 1, a vertical tube reactor 1 of cylindrical design is shown in cross-section, wherein the width is exaggerated in comparison to the length. Typically, the length is in the range of 500-1500 meter.

20 The downward tube section of the reactor comprises a feed tube 3 for the transport of a slurry of oil sands, the transport direction being depicted by an arrow.

The upward tube section of the reactor comprises a first exit tube 5 and a second exit tube 7, through which 25 material is transported upwardly, as indicated by the arrows .

A hydrocyclone 12 is provided at the bottom of the tube reactor, having an inlet 14 and two outlets defined as an overflow 16 and an underflow 18 respectively. The inlet 14 30 is fluidly connected to the feed tube 3. The overflow 16 is fluidly connected to the first exit tube 5 and the underflow 18 is fluidly connected to the second exit tube 7.

11

In the hydrocyclone 12 the feed of oil sands is separated into an overflow fraction comprising a high content of the bitumen component and/or hydrocarbons derived from bitumen, and an underflow fraction comprising a high 5 content of water, sand and minerals. The overflow fraction exits the cyclone 12 through overflow outlet 16, and the underflow fraction exits the cyclone 12 through underflow outlet 18. The solid compounds present in the underflow fraction precipitate at the reservoir 20. The precipitate in 10 reservoir 20 can be removed separately through a third exit tube 22.

In the first exit tube 5, a conduit 24 for gas injection is provided from which oxygen gas is delivered at its end proximate to the overflow outlet 16. Consequently, 15 the overflow stream containing bitumen component and/or hydrocarbons derived from bitumen is directly subjected to an oxidation reaction.

In the second exit tube 7, a conduit 26 for gas injection is provided from which oxygen gas is delivered at 20 its end proximate to the reservoir 20. Consequently, any bitumen component and/or hydrocarbons derived from bitumen that are present in the underflow, are directly subjected to an oxidation reaction.

In the third exit tube 22, a conduit 28 for gas 25 injection is provided from which oxygen gas is delivered at its end proximate to the reservoir 20. Consequently, any bitumen component and/or hydrocarbons derived from bitumen that are still present in the solids transported through the tube 22, are directly subjected to an oxidation reaction.

30 Schematically, a separate tube section 30 is depicted for heat exchange with the upward and/or downward tube sections .

12

Typically, the following parameters apply to the process : - The feed is pumped into the feed tube under a pressure of 20 bar maximum. The stream leaving the reactor at 5 the top of the first exit tube 5 has a pressure value comparable to the feed pressure.

- The operational pressure drop in the hydrocyclone is around 2 bar. Pressure reducing valves control the precise pressure of the stream of oil sands that is 10 introduced in the cyclone, so that the operational pressure drop is ensured.

- The pressure at the bottom of the reactor is dependent of the length of the vertical tube and the specific density of the hydrostatic column - typically the 15 pressure at the bottom is between 50 and 150 bar.

- At the inlet of the cyclone 12, a temperature is maintained between 150-250 °C, - In the first exit tube 5 and near the end of conduit 24, a temperature is maintained between 250-400 °C.

20 - In the second exit tube 7 and near the end of conduit 26, a temperature is maintained between 200-300 °C.

- In the third exit tube 22 and near the end of conduit 28, a temperature is maintained between 200-300 °C.

25 Possibly, the bituminous material of the oil sands is in part converted into gaseous products such as CH4 and H2S. These gaseous streams are separated and treated using commonly known processes.

30 By processing oil sands using the vertical tube reactor in the above described way for recovery of hydrocarbons from oil sands, it is possible to achieve a 60% reduction of 13 energy consumption needed and a 50% reduction of C02 produced, in comparison to known techniques.

Furthermore, the side products recovered from the process (i.e. water, sand, clay minerals) are 80% more pure. 5 Subject to the specific dimensions of the vertical tube reactor, it is possible to process a feed of oil sands of 100 cubic metre per hour in the tube reactor.

Based on an average content of 10 wt. % bituminous material in oil sands, a production of 1 million barrel of petroleum 10 products is projected.

Claims

A vertical tube reactor for processing tar sands, comprising: a downward tube section and an upstream tube section in fluid communication with each other on the bottom side of the tube reactor, the downstream tube section comprising a supply tube for transporting tar sands, the upward tube section a first outlet tube and a second outlet tube, characterized in that a cyclone is provided at the bottom of the tubular reactor, the cyclone having an inlet and two outlets defined respectively as an overflow and an underflow, the inlet being liquid is connected to the supply tube, and the overflow is fluidly connected to the first output tube and the underflow is fluidly connected to the second output tube.

2. Vertical tube reactor according to claim 1, wherein the tube reactor is positioned vertically in the ground and extends for the most part in the ground, the tube reactor having a total length between 500 and 1500 m.

The vertical tube reactor according to any of the preceding claim, wherein the cyclone is a hydrocyclone suitable for separating a liquid suspension into two fractions.

Vertical tube reactor according to any of the preceding claim, wherein a reservoir for collecting solid particles is provided between the underflow and the second output tube and in liquid communication with both.

The vertical tube reactor of claim 4, wherein the up section comprises a third output tube for transporting solid particles.

A vertical tube reactor according to any one of the preceding claim, wherein gas injection lines are provided in the first, the second and / or the third output tube.

7. Vertical tube reactor according to any of the preceding claim, further comprising a separate tube section for heat exchange with the up and / or down tube sections.

8. A vertical tube reactor according to any one of the preceding claim, wherein the cyclone is present in a cyclone unit that forms a detachable part of the tube reactor, and which cyclone unit can be assembled directly at the intended position within the tube reactor.

9. Vertical tube reactor according to any one of the preceding claim, wherein the tube reactor is provided with more than one cyclone at the bottom of the tube reactor.

10. Method for processing tar sands using the vertical tube reactor according to any of the preceding claims, wherein the method comprises the steps of: - introducing a slurry of tar sands into the feed tube and the subsequent downward transport of the slurry to the cyclone, wherein the slurry essentially comprises a mixture of water, sand, minerals and bitumen; - separating the slurry of tar sands into two fractions by the action of the cyclone, so that an overflow fraction is obtained which comprises a high content of bitumen component and / or hydrocarbons derived from bitumen component, and an underflow fraction is obtained that has a high content of water , sand, minerals; - guiding the overflow traction through the overflow outlet of the cyclone, through the first output tube of the tubular reactor; - passing the undercurrent fraction through the undercurrent outlet of the cyclone, through the second output tube of the tubular reactor /

11. Method as claimed in claim 10, further comprising the steps of: - introducing an oxidizing agent, preferably oxygen gas, via gas injection lines into the first, the second, and / or the third output tube.

12. Method as claimed in any of the foregoing claims 10-11, further comprising the step of: - collecting solid particles from the underflow fraction in a reservoir which is positioned between the underflow and the second output tube, which reservoir is fluidly connected to both, and preferably the step of transporting the solid particles through a third output tube.

A method according to any of the preceding claims 10-12, further comprising the step of: - transporting heat to the up and / or down tube sections by heat exchange, preferably via a separate tube section for heat exchange inside the tube reactor.