FIELD OF THE INVENTION The invention relates to apparatus and methods for the modification, processing or manufacture of bitumen and/or other petroleum products.

BACKGROUND TO THE INVENTION Reference to any prior art in this specification does not constitute an admission that such prior art forms part of the common general knowledge.

Bitumen is a viscoelastic mix of hydrocarbons used to hold together aggregates in pavements. It is a highly viscous waterproof adhesive at ambient temperatures. Bitumen is generally sourced as a fraction from the distillation of crude oil, but may also be found in natural deposits. One way to use bitumen in road pavements is to spray the bitumen at elevated temperatures onto the road pavement surface and then to apply stone chips (generally single sized aggregates) to the bitumen surface. This is variously known as bitumen spray sealing, bitumen seal coating, chip sealing or surface dressing. This can be contrasted with "hot-mix" or asphaltic concrete applications where bitumen and the aggregate are mixed together at elevated temperatures and then applied to a substrate. In cold-mix (or plant-mix) applications highly cutback bitumen and aggregate are mixed together at ambient temperatures and then applied to a substrate.

Modifying bitumen and more particularly modifying the properties of bitumen by oxidising the bitumen is known. Oxidised or so-called "blown bitumen" is obtained by blowing or passing air through the bitumen when the bitumen is at a very high temperature e.g. 200-350°C typically 240 to 280°C. The resultant modified bitumen is harder i.e. has an increased softening temperature and viscosity at comparable temperatures. With use of appropriate reagents the properties of the bitumen can be modified further such that the bitumen viscosity is less temperature susceptible. The process of modifying bitumen by blowing is relatively slow. It can also be inherently dangerous due to the presence of volatile hydrocarbons in any airspace within the bitumen modifying apparatus. The process may also result in significant carbon deposits. The process is frequently inefficient. There may also be present the real risk of fire or explosion and consequential damage to plant and potentially injury to personnel.

The Applicant proposed improvements in bitumen modification apparatus and methods in its US Patent No. 7,871 ,509, the entire contents of which are hereby incorporated by reference herein. Further improvements are the subject of this patent specification.

It is an object of the invention to provide an improved reactor apparatus for modification, processing or manufacture of bitumen and/or other petroleum products. It is a further object of the invention to provide an improved modification method for modification of bitumen and/or other petroleum products.

Each object is to be read disjunctively with the object of at least providing the public with a useful choice.

SUMMARY OF THE INVENTION

In a first aspect the invention provides a bitumen or petroleum product processing apparatus including:

a flow path through which bitumen or petroleum product and gas flow at a pressure above atmospheric pressure; a pressure reducer configured to reduce the pressure of the bitumen or petroleum product and gas; and

a gas separation unit including:

an inlet configured to receive reduced pressure bitumen or petroleum product mixed with gas from the pressure reducer;

a separation volume into which bitumen and gas pass from the inlet;

a gas outlet for removal of gas that separates from the bitumen in the separation volume; and

a bitumen or petroleum product outlet for extraction of bitumen or petroleum product from the separation volume.

Preferably the pressure reducer is a variable flow regulator. Preferably the pressure reducer is a valve. Preferably the pressure reducer is a globe valve. Preferably the pressure reducer reduces the pressure to substantially atmospheric pressure.

Preferably the separation volume is elongate or flat in the horizontal plane, so as to maintain a high surface area relative to volume for bitumen or petroleum product in the separation volume.

Preferably the apparatus includes a spray arrangement configured to spray bitumen or petroleum product mixed with gas into the separation volume. Preferably the spray arrangement includes one or more rotating substantially conical or frustoconical elements positioned to receive bitumen or petroleum product from the inlet. Preferably the one or more rotating elements include two or more substantially conical or frustoconical elements mounted concentrically. Preferably the spraying arrangement is configured to spray bitumen or petroleum product mixed with gas into the separation volume above a level of bitumen or petroleum product residing in the separation volume. In a second aspect the invention provides a bitumen or petroleum product processing apparatus having a gas separation unit including:

a separation volume;

a spray arrangement configured to spray bitumen or petroleum product mixed with gas into the separation volume;

a gas outlet for removal of gas that separates from the bitumen or petroleum product in the separation volume; and

a bitumen or petroleum product outlet for extraction of bitumen or petroleum product from the separation volume. Preferably the spray arrangement includes one or more rotating substantially conical or frustoconical elements positioned to receive bitumen from the inlet.

Preferably the one or more rotating elements include two or more substantially conical or frustoconical elements mounted concentrically.

Preferably the spraying arrangement is configured to spray bitumen or petroleum product mixed with gas into the separation volume above a level of bitumen or petroleum product residing in the separation volume. Preferably the separation volume is elongate or flat in the horizontal plane, so as to maintain a high surface area relative to volume for bitumen or petroleum product in the separation volume.

In a further aspect the invention provides a bitumen or petroleum product processing apparatus having a gas separation unit including:

an inlet configured to receive bitumen or petroleum product mixed with gas; a separation volume into which bitumen or petroleum product and gas pass from the inlet, the separation volume being elongate or flat in the horizontal plane, so as to maintain a high surface area relative to volume for bitumen or petroleum product in the separation volume;

a gas outlet for removal of gas that separates from the bitumen or petroleum product in the separation volume; and

a bitumen or petroleum product outlet for extraction of bitumen or petroleum product from the separation volume. Preferably the apparatus includes a spraying arrangement configured to spray bitumen or petroleum product mixed with gas into the separation volume above a level of bitumen or petroleum product residing in the separation volume.

In another aspect the invention provides a bitumen or petroleum product processing apparatus including:

a flow path;

a bitumen or petroleum product inlet for introduction of bitumen or petroleum product into the flow path;

a bitumen or petroleum product outlet for extraction of processed bitumen or petroleum product from the flow path;

a plurality of static mixers positioned in a section of the flow path;

a pump arranged to pump bitumen or petroleum product through the plurality of static mixers;

two or more shut-down valves arranged to close the section of the flow path, thereby limiting or preventing ingress of air and/or oxygen into the closed section of the flow path when the apparatus is shut down.

Preferably the apparatus includes one or more inlets for introduction of air and/or reagents and/or catalysts into the flow path. In a further aspect the invention provides a bitumen or petroleum product processing apparatus including:

a flow path;

a bitumen or petroleum product inlet for introduction of bitumen or petroleum product into the flow path;

a bitumen or petroleum product outlet for extraction of processed bitumen or petroleum product from the flow path;

one or more first inlets for introduction of air and/or reagents and/or catalysts into the flow path;

a first plurality of static mixers positioned in a first section of the flow path downstream of the bitumen or petroleum product inlet and the one or more first inlets;

a first pump arranged to pump bitumen or petroleum product and air and/or reagents and/or catalysts through the first section of the flow path;

a first gas separation unit positioned downstream of the first section of the flow path, configured to separate gas from bitumen or petroleum product;

one or more second inlets for introduction of air and/or reagents and/or catalysts into the flow path downstream of the first degasser unit;

a second plurality of static mixers positioned in a second section of the flow path downstream of the second reagent inlets;

a second pump arranged to pump bitumen or petroleum product and air and/or reagents and/or catalysts through the second section of the flow path; and a second gas separation unit positioned downstream of the second section of the flow path, configured to separate gas from bitumen or petroleum product.

Preferably the apparatus includes a pressure reducer positioned before each gas separation unit.

Preferably the flow path forms a closed loop such that bitumen or petroleum product circulates within the apparatus. This aspect also extends to a bitumen processing or manufacturing system including two or more such apparatuses, connected in series.

In another aspect the invention provides a bitumen or petroleum product processing apparatus including:

one or more bitumen or petroleum product inlets for introduction of bitumen or petroleum product;

one or more bitumen or petroleum product outlets for extraction of processed bitumen or petroleum product;

a plurality of reactor stages each including:

one or more inlets for introduction of air and/or reagents and/or catalysts;

a plurality of static mixers;

a pump arranged to pump bitumen or petroleum product and air and/or reagents and/or catalysts through the plurality of static mixers; and

a gas separation unit positioned downstream of the plurality of static mixers, configured to separate gas from bitumen or petroleum product;

the apparatus being configured for operation of two or more of the plurality of reactor stages in series, or for operation of each of the plurality of reactor stages independently.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example only, with reference to the accompanying drawings, in which: is a schematic diagram of an apparatus according to one embodiment;

is a more detailed view of the spray arrangement of Figure 1 ;

is a cut-away view of the spray arrangement;

is a cut-away view of a further embodiment of a spray arrangement; Figure 3 shows one embodiment of control arrangement for the apparatus of Figure 1 ;

Figure 4 shows an apparatus according to a further embodiment;

Figure 5 illustrates a first mode of an apparatus according to a further embodiment;

Figure 6 illustrates a second mode of the apparatus of Figure 5;

Figure 7 illustrates a third mode of the apparatus of Figure 5; and

Figure 8 shows an apparatus according to a further embodiment; DETAILED DESCRIPTION

Figure 1 shows a modification apparatus or reactor 1 according to one embodiment. The apparatus is described, by way of example only, with reference to modification of bitumen. However, the Applicant's apparatus may be used for modification of other petroleum products. For example, in one embodiment discussed below the apparatus may be used for processing of other petroleum products to produce bitumen.

In preferred embodiments the apparatus 1 is a continuous loop reactor apparatus, as shown. Bitumen circulates through the apparatus 1 in the direction indicated by arrows 2. As discussed below, inlets and outlets allow for introduction of bitumen and other reagents and/or catalysts, and for the extraction of modified bitumen from the apparatus 1. In other embodiments the apparatus may be a linear reactor apparatus, with bitumen passing from an inlet end to an outlet end of the apparatus.

The apparatus includes a bitumen inlet 3, through which bitumen can be added to the tubular path of the continuous loop reactor apparatus 1. Near, and preferably downstream of the bitumen inlet 3, one or more reagent and/or catalyst inlets 4, 5 are provided for introduction of reagents and/or catalysts to the tubular path of the continuous loop reactor apparatus 1. The apparatus includes a first reactor stage 6. In this first reactor stage 6, a pump 7 causes bitumen and any reagents (including air) and/or catalysts to flow along the flow path 8 towards and through a first mixing stage 9. The first mixing stage 9 includes a tubular path containing a first plurality of static mixers 10. As shown in Figure 1 , the first plurality of static mixers 10 may be positioned in a number of vertical columns 11 , 12. However, other arrangements of the tubular path in the first mixing stage may be used. In general a number of mixing stages may be provided, and each mixing stage includes a section of the tubular path containing a number of static mixers.

The static mixers are fixed, non-moving components that cause mixing of the bitumen and reagents and/or catalysts flowing through them. Various types of static mixer are known. Preferably the mixers are formed from a strong inert material that is resistant to the bitumen or other petroleum product being modified and to any other reagents, catalysts or reaction products. The mixers may be formed from stainless steel.

The pump 7 provides velocity of the fluid flow within the apparatus to match the functionality of the static mixers. The static mixers create rapid changes in direction of the fluid flow and the resulting turbulent flow creates intimate intermixing of all components in the fluid flow.

Due to the plurality of static mixers in the first mixing stage 9, the bitumen and other reagents and/or catalysts are highly mixed, leading to excellent reaction rates in the first mixing stage 9. After exiting the first mixing stage 9, bitumen flows through a pressure reducer 14. The pump 7 is operable to maintain a pressure through the first mixing stage of around 6 to 7 bar. The pressure reducer 14 reduces the pressure to around 1 bar, or more generally around 1-2 bar, downstream of the pressure reducer. An exit column 15 may be provided in the first reactor stage 6, leading to a first gas separation or degasser unit 16. The first degasser unit separates gasses from the bitumen stream. The first degasser unit includes a separation volume 17, which may be a tank as shown. Bitumen is introduced into the separation volume through an inlet arrangement 18, which is shown in detail in Figure 2. The inlet arrangement 18 includes an inlet 19 through which bitumen flows from the pressure reducer 14. The bitumen is directed from the inlet 19 to a spray arrangement 20. The spray arrangement 20 is configured to spray the mixed bitumen and air into the separation volume. As the mixed material is sprayed, gases tend to separate from the sprayed film or droplets of bitumen. The bitumen droplets then fall downwards, or the bitumen film falls downwards. The approximate level of bitumen in the separation volume 17 is marked 22 in Figure 1. The level can be maintained within desired limits, as discussed below. In one embodiment the spray arrangement 20 may include a spray head 23, shown in more detail in Figures 2 and 2A. The spray head 23 may include a number of elements 24, 25, 26 mounted so as to create a number of flow paths 27, 28 through the spray head 23. Any number of spray head elements may be used to create any desired number of flow paths. Bitumen flows from the inlet 19 through the flow paths 27, 28 and is sprayed into the separation volume 17. In the embodiment shown the elements 24, 25 are generally truncated conical or frustoconical elements extending from tubular lower sections 29, 30. The central element 23 may be conical.

In preferred embodiments the spray head 23 is a rotating spray head. The rotating spray head may be mounted to a shaft 32 driven b a suitable motor 33. The rotation may be in the range 300 to 1000 rpm. The cones may have maximum diameter in the range 200-400mm, preferably around 300mm. The cones may be formed from 2mm thick stainless steel. In one embodiment the conical walls may be formed at an angle of around 45 degrees to the vertical. In another embodiment the tops 24', 25', 26' of the cones 24, 25, 26 may be curved towards the horizontal, as shown in Figure 2B. This alters the angle at which the bitumen is sprayed into the separation volume. This rotation effectively throws the bitumen outwards, assisting in spraying of the bitumen from the spray head into the separation volume and forming a three dimensional curtain of bitumen droplets or a three dimensional bitumen film. A significant proportion of gas separates from the bitumen as it is sprayed. In some embodiments, other spray arrangements may be suitable, including: simple conical spray heads (i.e. including only a single conical element), rotating and stationary spray heads, spray nozzles etc. Multiple spray heads may be used in each degasser unit. In some embodiments the spray arrangement may be replaced by a simple inlet, with bitumen spilling from the inlet into the separation volume. Such a mechanism is disclosed in US7,871 ,509.

The pressure reducer also assists in separation of gas and bitumen. As the pressure reduces gas in the bitumen stream tends to coalesce to form bubbles. Solubility of air and some other gases in bitumen also falls with decreasing pressure.

All of the gas mixed with the bitumen is not necessarily separated during the spraying of bitumen by the spray arrangement 20. In order to provide further separation of gas, bitumen is maintained in the separation volume up to the level marked 22 in Figure 1. The bitumen has a residence or dwell time within the separation volume, and during this period more gases are released from the bitumen into the volume 35 above the bitumen level 22. The shape of the separation volume 17 assists here. The separation volume is preferably either elongate or flat in the horizontal. This presents a large surface area per unit volume of bitumen within the separation volume 17. Gas exits the degasser through a gas outlet 36. The gases may include low oxygen content air and volatiles, but the gas content will depend on the particular application of the apparatus. While not shown, an explosion vent may be connected to the gas outlet 36. One or more separators may be used to separate liquids and solids from the gas stream (e.g. water with minor amounts of carbon and liquid hydrocarbons). Gases passing through the gas outlet may pass to an incinerator (not shown).

In one embodiment the output gases may pass to a heat exchanger type incinerator so that the burnt off air/vapour mixture can be used as an energy source, to be used for example in heating thermal oil passing through a coil of the heat exchanger. The heated thermal oil can then be used for other processing activities such as preheating of the bitumen and/or air. Alternatively the air and volatiles may be fed into a simple incinerator for burning off.

To maintain the bitumen at the appropriate level, a level sensor may be provided. A number of tubes 37 are mounted to the separation volume 17. The level sensor 38 mounts to the top of tube 39, which contains bitumen at the same level as the separation volume 17. The level sensor in one embodiment may be a radar unit configured to sense the bitumen surface (and therefore the bitumen level) within the tube 39.

The first reactor stage therefore includes the first pump 7, inlets 3, 4, 5, first mixing stage 9 and first degasser unit 16. Bitumen exits the first degasser unit 16 by an outlet 46 and passes to a second reactor stage 47. The second reactor stage includes a second pump 48, inlets 49, 50, second mixing stage 51 and second degasser unit 52, which function in a similar manner to the corresponding elements of the first reactor stage. In general, any number of reactor stages may be connected in series in this way. The apparatus 1 may therefore include a first reactor stage and a number of additional reactor stages connected in series. Each stage modifies the bitumen passing through it.

The effect of the two or more stages is as follows. Bitumen introduced to the apparatus through inlet 3 is mixed with reagents and/or catalysts introduced through inlets 4, 5 in the first mixing stage 9. Partially modified bitumen passes through the first degasser 16 where gases are removed. Where the modification is by air or oxygen, the degasser will remove undesirable spent gases and gaseous reaction products. The partially modified bitumen is pumped by pump 48 from the first degasser into the second reactor stage. Further reagents and/or catalysts are then introduced through inlets 49, 50 in the second reactor stage. The bitumen and further reagents and/or catalysts are then mixed in the second mixing stage 51 , further modifying the bitumen. The further modified bitumen passes through the second degasser 52 where gases are again removed. This process may be repeated in a number of further reactor stages if desired. This dramatically improves the efficiency of bitumen processing over a single stage apparatus. In a two stage apparatus the increase in efficiency is greater than a two-fold improvement that might be expected by doubling the number of stages. Modified bitumen is removed from the apparatus through outlet port 55. This extraction is driven by an extraction pump 56. Where the apparatus is in the form of a continuous loop reactor, only a portion of bitumen may be extracted through the outlet port, with the remainder of the bitumen recirculating for further modification. The apparatus of Figure 1 may be shut down as necessary without emptying the apparatus of bitumen. As the bitumen cools it contracts and its viscosity increases. In order to shut down the apparatus, the level of gas in the system is preferably reduced by running the apparatus for several minutes without introduction of further bitumen, reagents or catalysts. The degasser units 16, 52 continue to operate during this period. At the conclusion of this period the bitumen in the tubular path has a reduced gas content. The pumps 7, 48 are then shut down, which causes the cessation of bitumen flow through the apparatus. Shut-down valves are then closed to isolate the mixer stages. In the embodiment shown there are four shut-down valves. In one embodiment the first and second pressure reducers 14, 14' may be in the form of valves. These valves also act as shut-down valves. However, in other embodiments separate shut-down valves and pressure reducers may be provided. Returning to the embodiment of Figure 1 , two further shut-down valves 58, 58' are also provided. These may be knife-valves or any other valve suitable to close the tubular path. In the shut-down phase, the first knife valve 58 and first pressure reducer valve 14 close to isolate the first mixer stage 9. The second knife valve 58' and second pressure reducer valve 14' close to isolate the second mixer stage 51.

Isolation of the mixer stages in this way prevents or at least limits the ingress of air or oxygen containing gases into the mixer stages when the plant is shut down. This is desirable because bitumen continues to oxidise as the plant is shut down and when it is started up. In these shut down and start up periods the bitumen in the apparatus transitions between the high operating temperature and lower ambient temperature. At temperatures above about 140 degrees significant oxidation will occur. If uncontrolled oxidation is allowed in the mixer stages after the apparatus is shut down, coking will slowly build up on the mixers, limiting their efficacy or even blocking the flow path.

The apparatus including the pumps and the tubular path may be jacketed. Thermal oil may be passed through the jackets for preheating the apparatus and contained bitumen as well as the bitumen pumps prior to startup or restarting of the modification process. A number of heating jackets 40 are shown in Figure 1. Further jackets may be used but are not shown for reasons of clarity.

At initial start-up of the apparatus or reactor will be filled with bitumen prior to the introduction of air, other reagents and/or catalysts. If the pump is being restarted the shut-down valves will be closed and must be reopened. Slowly the first and second pumps 7, 48 will be bought up to operating conditions. Reagents and catalysts can then be introduced to establish a stable operating condition.

Bitumen may be pre-heated before introduction through the inlet port 3. In one embodiment, where bitumen is to be modified by "blowing", bitumen may be supplied to the bitumen inlet 3 at a temperature of about 220-230°C which results in the processed bitumen exiting the reactor at a temperature of about 230-240°C.

Bitumen, air, other reagents and catalysts may also be supplied at a pressure close to the operating pressure used in the mixing stages, preferably around 6 to 7 bar.

In the embodiment of Figure 1 , the first pump 7 acts to cause bitumen to flow through the first reactor stage. However, it also acts a circulation pump, causing bitumen to flow from the outlet 46' of the second degasser back to the first mixing stage 9. In other embodiments a separate circulation pump may be used.

The pressure reducers 14, 14' may be any suitable arrangement for reducing pressure. Preferably the pressure reduction is sudden, i.e. close to a step reduction. In one embodiment each pressure reducer may be a globe valve. In other embodiments any suitable pressure reducing valve or other pressure reducing arrangement (for example an orifice plate) may be used. In preferred embodiments the pressure reducers may be adjustable.

The apparatus may be controlled as described below, with reference to Figures 1 and 3.

The movement of bitumen through the static mixers is controlled principally by the first and second pumps 7, 48. The amount of bitumen in the apparatus is controlled by the combined action of the inlet pump 60 and extraction pump 56. The inlet pump adds bitumen to the recirculating bitumen within the apparatus. When the level of bitumen within the apparatus is sufficiently high, bitumen will build up in the tubular path in the degassers 16, 47 and in the sections of tubular path 61 , 62 immediately downstream of the degassers 16, 47.

By sensing the level of bitumen in this region, preferably in the degassers, the second pump 48 and the extraction pump 56 can be controlled as follows. When the level in the first degasser 16 exceeds a threshold, the rate of the second pump 48 increases to pump bitumen through the second mixer stage 51. When the level in the second degasser 52 exceeds a threshold, the rate of the extraction pump 56 is increased to extract modified bitumen from the apparatus. By controlling bitumen movement and extraction in this way, the level of bitumen can be kept within desired limits for optimum operation of the apparatus.

Furthermore, operation of the inlet pump can be used to control the number of circulations around the apparatus that bitumen will go through, providing some control over the level of bitumen modification. For example, if the inlet pump is run at a low rate, bitumen will on average pass around the apparatus many times before being extracted because bitumen will build up in the separation volumes at a lower rate. If the inlet pump is run at a high rate, bitumen will build up at a greater rate and will on average pass around the apparatus a lesser number of times before being extracted. The level sensors and associated control therefore provides an excellent and convenient mechanism for automatically controlling the level of bitumen in the apparatus and extraction of bitumen from the apparatus for many different levels of modification. The control of the inlet and extraction pumps therefore provides the mechanism for controlling dwell time of bitumen within the reactor, and therefore (along with other parameters such as the reagents and/or catalysts used, temperature and pressure) the level of modification that will occur. Figure 3 shows a central controller 65, which receives information from sensors and provides control signals to at least some of the various pumps and valves discussed above. The controller provides control signals to the input pump 60, catalyst pumps 66, 67, reagent pumps 68, 69, first pump 7, second pump 48 and extraction pump 56. In some embodiments some of these pumps may be fixed rate pumps that do not need to be controlled. However, preferably at least the second pump 48 and extraction pump 56 are controllable. In more preferred embodiments all of the above pumps are controllable. The pumps may be controlled by varying their rate, or by switching the pumps on or off. Pumping rate may be varied by direct control of the rate, or by switching the pump on and off to vary its duty cycle. Further, the pumps may provide feedback information to the controller on their current status, pumping rate etc. The controller 65 receives information from a number of sensors. These include the first and second level sensors 38, 38', temperature sensors and any other sensors that may be desirable for the particular application.

The controller 65 may also control and receive feedback from the valves 14, 14', 58, 58'. This enables the controller to control the shut down process described above, as well as the pressure drop across globe valves 14, 14'. Alternatively, these valves may be operated manually.

The flow path may have a diameter around 25 to 300 mm, with the larger sizes preferred for industrial applications.

Any reagents suitable for the desired modification process may be used. For example, various forms of phosphoric acid may be used in bitumen blowing. Any catalysts suitable for the desired modification process may be used. For example metal halides such as ferric chloride may be used as a catalyst for blowing bitumen. The apparatus has been described above in relation to modification of bitumen, in particular but not exclusively to blowing bitumen. However, the apparatus may also be used for processing of other substances, in particular petroleum products including refinery products produced from crude oil, as well as unconventional petroleum sources such as heavy oil seepage, tar sands, bituminous sands and oil sands.

For example, the apparatus may be used for the manufacture of bitumen from other crude oil fractions. Vacuum residues (also known as vacuum bottoms or short residues) may be processed to form bitumen, by an oxidation process over a relatively long residence time, with phosphoric acid as a reagent. Products from heavy oil seepage, tar sands, bituminous sands and oil sands, may all be processed by the apparatus to provide bitumen.

Bitumen products that are not suitable for many applications may be processed to a more useable form for a particular application. For example, solvent precipitated bitumen (also known as solvent de-asphalted bitumen) is in general too viscous for roading applications. However, it may be processed using flux oil and air rectification with the Applicant's apparatus to form a less viscous bitumen suitable for roading. Fluxing oils and/or other additives may be added as required for the particular application, either before or after other reactions have taken place.

The apparatus may also process blends of any of the above substances, or blends of the above substances with bitumen. The apparatus may be used for various processes including, but not limited to: air rectification of bitumen or petroleum products; dehydrogenation and/or oxidation; polymerisation and/or cross-linking; high shear mixing of thermoplastics into bitumen.

Suitable reagents include oxygen, various forms of phosphoric acid. Catalysts include ferric chloride. Flux oils include suitable vegetable oils, mineral oils, recycled oils etc. Polymers include styrene-butadiene-styrene (SBS) polymers, styrene- butadiene rubber (SBR), latex rubber, ground tyre rubber etc. Waxes may be used.

Oxygen will generally be obtained simply by using air, as purified oxygen adds cost. However, purified oxygen may be used in some applications.

In general the Applicant's apparatus creates excellent reaction conditions for modification or processing of bituminous products or petroleum products, or for manufacture of bitumen from other products, especially petroleum products.

Compared to the Applicant's apparatus described in US7,871 ,509, the system of Figure 1 provides a longer time for bitumen to make one circulation through the apparatus. However, the total residence time for bitumen in the apparatus, in order to achieve a certain level of modification, is reduced.

Figure 4 shows an apparatus according to a further embodiment. In this apparatus, two of the apparatuses discussed above are connected in series. Thus, a first apparatus 1 includes first and second reactor stages 6, 47 and a second apparatus 1' includes first and second reactor stages 6', 47'. The extraction port 55 of the first apparatus 1 is connected to a bitumen inlet 3' of the second apparatus 1'. Any number of apparatuses may be connected in series in this manner.

The chemical processes in each apparatus 1 , 1' may be the same. Alternatively, different reagents and/or catalysts may be used in the different apparatuses 1 , 1'. Figures 5 to 7 illustrate a further embodiment of a two mixer stage modification apparatus or reactor 101 in which three different flow modes may be implemented. Advantageously this allows each stage to be shut down or operated independently of the other. One stage may therefore be serviced, for example, while the other stage continues production.

In this embodiment the apparatus 101 is also in the form of a continuous loop reactor apparatus. However, several loop paths are possible. In each mode some valves are closed and some pumps unused. For clarity closed valves and unused pumps are indicated in black fill for each mode.

Figure 5 illustrates a first mode in which the two stages are connected in series with a left side inlet. Bitumen circulates through the apparatus 101 in the direction indicated by arrows 102.

The apparatus includes a bitumen inlet 03, through which bitumen can be added to the tubular path of the continuous loop reactor apparatus 101. Bitumen flows along flow paths 104, 105, 106 to a right hand reactor stage 107. One or more inlets 08, 108a are provided for introduction of air and/or reagents and/or catalysts to the tubular path of the continuous loop reactor apparatus 101.

In this right hand reactor stage 107, a pump 109 causes bitumen and any air, reagents and catalysts to flow along the flow path towards and through a first mixing stage 110.

The first mixing stage 110 includes a tubular path containing a first plurality of static mixers 111 and is similar to the mixing stages discussed above.

After exiting the first mixing stage 110, bitumen flows through a pressure reducer 112 and degasser unit 113, which also operate as discussed above. Bitumen exits the right hand degasser unit 113 via flow paths 115, 116, 117 and is pumped by pumps 118 and/or 139 to a left hand reactor stage 119. In this configuration one of these two pumps (e.g. pump 118) may operate in a fixed rate mode, while the other (e.g. pump 139) has a variable rate to control the level of bitumen in the degasser 113.

The left hand reactor stage includes inlets 120, 121 , second mixing stage 122 and second degasser unit 123, which function in a similar manner to the corresponding elements of the right hand reactor stage.

Bitumen exits the left hand reactor stage 119 via flow path 125. A pump 126 operates as a circulation pump to pass bitumen back to the right hand reactor stage 107 via flow paths 127 and 106. A pump 129 acts as an extraction pump to extract processed bitumen through the outlet 130.

In this mode, valves 131 , 132, 133, 134, 135, 136 and 137 are closed and pump 138 is inactive. A pump 139 maintains a circulating flow through flow paths 140, 141, 142. However, in some embodiments this flow loop may be closed by valves 143, 144.

Figure 6 illustrates a second mode of operation for the apparatus shown in Figure 5. The two stages are connected in series with a right side inlet. Bitumen circulates through the apparatus 101 in the direction indicated by arrows 102. In this mode the bitumen inlet is marked 202. Bitumen flows along flow paths 104, 203, 204 to the left hand reactor stage 119. After exiting the left hand reactor stage 119, bitumen is pumped by pump 126 through flow paths 125, 127, 106 to the right hand reactor stage 107. In this mode pump 139 acts as an extraction pump to extract bitumen from outlet 205. The pump 118 acts as a circulation pump to cause bitumen to return to the left hand reactor stage 119 via flow paths 117, 204. In this mode valves 206, 207, 208, 209, 132, 137 and 144 are closed and pump 109 is inactive.

This mode therefore operates in substantially the same manner to that of Figure 5, but the position of the inlet and outlet, and the flow direction in some flow paths, is altered.

Figure 7 illustrates a third mode of operation for the apparatus of Figures 5 and 6. In this mode each stage operates independently of the other. The valves 210, 211 , 212 are closed, preventing any flow between the two reactor stages 107, 119. This allows each stage to be operated alone, while the other is shut down. Valves 131 , 144 are also closed.

In the left hand reactor bitumen flows from an inlet 103 via pump 138 and flow paths 203, 204 to the left hand reactor stage 119. The pump 126 acts as a circulation pump, receiving bitumen from the degasser 123 and returning it to the left hand reactor stage 119. The pump 129 acts as an extraction pump for extracting processed bitumen through outlet 130. The extraction pump also controls the level of bitumen in the degasser 123.

Similarly, in the right hand reactor bitumen flows from an inlet 202 via pump 109 and flow paths 105, 106 to the right hand reactor stage 107. The pump 118 acts as a circulation pump, receiving bitumen from the degasser 113 and returning it to the right hand reactor stage 107. The pump 139 acts as an extraction pump for extracting processed bitumen through outlet 205. The extraction pump also controls the level of bitumen in the degasser 113.

In general, any number of reactor stages may be connected in this way, allowing operation of all or some reactor stages in series or independent operation of each reactor stage. The various elements of this apparatus may be controlled by a central controller in a similar manner to that discussed above.

An apparatus allowing independent or series operation of two or more reactor stages may be implemented with other configurations of the flow paths, valves and pumps, and other such configurations will fall within the scope of the invention.

Figure 8 shows an apparatus according to a further embodiment. In this apparatus, two of the apparatuses of Figures 5 to 7 are connected in series. Thus, a first apparatus 101 and a second apparatus 10 are connected. The extraction port 205 of the first apparatus 101 is connected to a bitumen inlet 103 of the second apparatus 101'. Any number of apparatuses may be connected in series in this manner. In one embodiment the apparatus is suitable for blowing bitumen. Blown bitumen is oxidised by reaction with air or other oxygen containing gas.

Note that some aspects of the invention may find application in single stage reactor apparatuses, and are not to be limited to the two or more reactor stage configuration unless explicitly limited by the appended claims.

The process and apparatus according to the present invention provides a very stable and controllable means of modifying bitumen. It also enables the production of a wide range of bitumen specifications including multigrade bitumens. Multigrade bitumens are less temperature susceptible bitumens.

The process can be carried out using catalysts and reagents that may be required in order to achieve the desired end specification of the bitumen. The use of a multistage apparatus further improves the efficiency of the reaction. Spent reagents and undesirable gaseous reaction products are removed from the system after each mixer stage, with fresh reagents and/or catalysts being added. Pumps in each reactor stage cause mixing at the desired pressure. Any number of mixer stages may be provided, with a gas separation unit after each mixer stage and a pump before each mixer stage.

The removal of spent or waste gases, including reaction byproducts, from the system and introduction of fresh gases improves performance.

The shut-down valves isolate the mixer stages during shut-down. Ingress of oxygen or other undesirable gases into the mixer stages after shut-down is therefore limited. This reduces the opportunity for undesirable coking of the mixer surfaces by oxidised bitumen or other materials, maintaining the static mixers in good working condition.

The degasser unit operates at reduced pressure, preferably around atmospheric pressure, which contributes to improved separation of gases and also to improved safety in some applications (as uncontrolled combustion is less likely at reduced pressure). The degasser unit includes a spray arrangement that sprays mixed bitumen into the separation volume, contributing to improved separation of gas and bitumen. Further, the shape of the separation volume provides a large bitumen surface area for bitumen residing in the tank, again contributing to improved separation of gas and bitumen.

Safety is also enhanced by the improved reaction conditions, as there is less surplus oxygen mixed with volatiles in the degassing units. For example, in some bitumen blowing applications the waste gas may be only around 5% oxygen. Combustion is therefore less likely.

While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.