The present invention is related to a device and method for purifying a polluted viscous crude oil product.

Within the context of the present invention, a polluted viscous crude oil product refers in particular to a residual product of crude oil refining, such as a visbroken residue, and more in particular an asphalt product. The wording viscous crude oil product therefore comprises more than just asphalt in the form of bitumen, although the present

invention is particularly well suited for it. It also relates to all crude oil products that are heavier than heavy fuel oil. However, hereinafter the wording product will be used to refer to the polluted viscous crude oil product described above .

During the Second World War, the emphasis with oil distillation was put on obtaining oil for the aircraft industry. Other products that are released during fractional distillation, such as asphalt, were regarded as unwanted byproducts in those times. Therefore, several dumping grounds exist worldwide wherein for example asphalt has been dumped in a lake . An example is the asphalt lake on the Dutch

Antilles .

Because the oil reserves are becoming more and more reduced, resulting in increasing oil prices, the interest for purifying the asphalt in the asphalt dumping grounds becomes stronger .

For purifying asphalt, it needs to be heated to

increase the fluidity. The temperatures that are needed lie above or about 135 degrees Centigrade.

A problem not yet solved is related to the explosive behaviour during the heating of the polluted asphalt. A cause for this behaviour is the moisture that is encapsulated in the asphalt. At high temperatures, the moisture cannot expand sufficiently as a result of which enormous pressure can build up in the asphalt.

The present invention provides a solution to the above mentioned problem. To this end, the invention provides a device for purifying a polluted product . This device comprises a holding unit for holding the polluted product to be purified as well as a rolling device disposed in the holding unit along or across which the product can move in a first direction. The rolling device is heated by a heating element. The device further comprises a pumping device for attracting the product that moves along or across the rolling device and a feedback device for feeding the attracted product back to the rolling device.

Within the context of the present invention, a holding unit is mostly a closable space such as a container or a bucket. Due to safety reasons it is advantageous to place the holding unit in the ground.

It is an important aspect of the present invention that the product is heated and moved simultaneously to prevent the abovementioned explosive behaviour. The movement should realize that the moisture in the product is not pressurized too much. This can be achieved by breaking the various moisture pockets in the product. On one hand, the product becomes liquid by heating, on the other hand the moisture can evaporate from the product .

The applicant has found that a rolling motion is a very advantageous type of motion when compared to for instance sliding. During rolling, the different parts of the product are in motion relative to each other as a result of which the breaking of the moisture pockets can take place

optimally. According to the invention, the product will move in a first direction. This motion can for instance be caused by the fact that the product moves along a wall which is inclined. Due to gravity, it will move downwards. However, mechanical means may be provided for stimulating such a movement. During the movement in the first direction, at least a part of the product will describe a rolling motion. Within the context of the present invention, a rolling motion should be construed as being a motion in which the product describes a non-linear motion causing it to deform. It is assumed that due to the deformation, a different part of the product lies at the surface each time whereby the moisture pockets are able to release at least a part of the built up pressure. The explanation given above should not serve to limit the scope of protection of the present invention.

The pumping device attracts the product after which it is fed back by a feedback device to the rolling device.

Because of this, a repeating process comes into being wherein moisture can be removed from the product more and more. The pumping device is disposed in such a manner that it attracts the product which has at least partly moved along the rolling device .

A particularly preferred embodiment of the feedback device comprises a spraying element for spraying the attracted product. In this spraying element, the product is sprayed through small openings. As a result, the surface of the product is increased considerably, which again allows the moisture to evaporate easily and which reduces the chances of explosive pressure build up.

Because the product contains other pollutions in addition to moisture, it is preferred to filter or sieve the product during the purifying. To this end, the feedback device can be provided with a sieve.

In an embodiment of the present invention, the rolling device comprises a downwardly oriented inclined wall. Due to the downward orientation of the wall, the product will describe a rolling motion under the influence of gravity. In order to obtain a rolling motion instead of for instance a sliding motion a balance needs to be found between among others the angle under which the wall is placed, the friction coefficient of this wall, and the viscosity of the heated product. Here, the angle of inclination of the wall is preferably not greater than 45 degrees.

The rolling device may further comprise a dumping wall which is configured as the wall described above and onto which the product to be purified can be dumped from the outside. This dumping wall is preferably configured such that the product dumped thereon rolls downwards .

The earlier mentioned wall and the dumping wall are, at least looking from the perspective of a horizontal plane, placed perpendicular to each other.

It is possible to only have the dumping wall heated by the heating element. After all, the explosive behaviour of the product is most dominant for recently dumped product because the temperature of that product is relatively low. By spraying the heated product that was already in the holding unit onto the recently dumped product, excessive pressure build up is prevented.

The wall could comprise a plurality of plates that at least partly overlap each other at least in the first direction. An example of this are plates that extend horizontally that overlap each other on an upper side and a lower side . At the overlapping of the plates, or in the wall in general, openings can be provided to a collecting space in the holding unit for feeding through and sieving of the product to be purified. The collecting space is preferably at least partly closed. Therefore, at least two spaces can be identified in the holding unit, namely a collecting space and a space in which the product moves along or across the rolling device. The openings in the wall are preferably either horizontal or running upwardly in an inclined manner. A possible shape for the opening is a slot which is formed because adjacent plates leave open a space through which the asphalt can move. Preferably, this opening has a length that substantially corresponds to the length of the plates and the opening has a height between 0.5 and 10 cm, more

preferably between 1 and 5 cm, and even more preferably between 2 and 4 cm.

In the abovementioned case, the pumping device can be provided with a first pump connected to the collecting space for attracting the product through the openings in the wall or the product that has already passed through the openings. Also this attracted product can be fed back. By attracting the product that has passed through the openings an under pressure can be created in the collecting space which has a suction effect on the product that moves along or across the rolling device. In another or further embodiment, the suction effect is of less importance and the first pump mainly serves to remove the product to make way for new product. It should be clear to the skilled person that the shape and size of the openings has an impact on the sieving operation and on the prevention of pressure build up in the product because it has to deform to pass through the

openings . The heating element can at least partly be arranged near a bottom of the device in the collecting space, wherein the first pump attracts the product such that the product is moved in a vicinity of the heating element that is arranged at least partly near the bottom. Because of this, the product that is attracted by the first pump is heated well before it is sprayed. This effect is preferably realized because the heating element comprises heated elongated elements that extend substantially parallel to the bottom at a predefined height relative to the bottom, wherein the first pump is arranged such that it attracts the product from a position in between the bottom and the predefined height. The objective being that the molten product can be fed back to the rolling device with a temperature of at least 100 degrees Centigrade and more preferably of at least 135 degrees Centigrade.

In an embodiment of the present invention, the device comprises aforementioned walls disposed oppositely and in a V-shape in between which downstream of the two walls a collecting element is disposed that is connected to the pumping device and which is configured for collecting the product that has moved along the walls. In this embodiment, the product is able to describe a rolling motion at two walls. The holding unit can therefore comprise two

collecting spaces. This arrangement is particularly

interesting if use is made of an elongated holding unit with parallel walls. The inclined walls could be attached to the walls in the length direction.

In an embodiment, the device comprises the earlier mentioned dumping wall that tapers to an end and as such is placed in the V-shape from a top side. The wall opposing the dumping wall can be realized in a perpendicular manner.

Here, it is also possible that two collecting spaces are defined that are connected by means of an open space

underneath the dumping wall. With such an embodiment, the walls do not extend, at least near the bottom of the device, over the full length of the device.

The pumping device can be provided with a second pump, disposed downstream of the rolling device, and configured for attracting the product that moves along or across the rolling device in the first direction. This pump can for instance be connected to the abovementioned collecting element. This element could comprise a trough or a similar elongated element that connects to the walls and in which a screw-type pump is arranged. Such a pump comprises an auger in the form of a screw. By driving this screw the product is transported parallel to the walls. At the end of the holding unit, the product can be fed back.

The feedback device is preferably configured for feeding back the product that has been attracted by the second pump to the collection space. This space could also be heated extra in addition to the heating by the adjacent plates.

For feeding the product to the holding unit, a glide wall can be used which is disposed in the holding unit and which exits on the rolling device. Exiting refers to the fact that the product glides in over the glide wall, and preferably even rolls, and that the product is then engaged by the rolling device. An example of this is a glide wall that connects to the abovementioned walls, which are

disposed in parallel. The glide wall can be configured as the earlier mentioned dumping wall.

Among others, an advantageous device is obtained in combination with the spraying element. To start the

deformation of the product directly at the moment that the product is placed onto the rolling device, the spay element is arranged such that the hot product, having a temperature of at least 100 degrees Centigrade and more preferably at least 135 degrees Centigrade, which sprays through the small openings of the spraying element, sprays onto the supplied product from multiple sides.

The result is that a block of product that only

recently has been dumped into the holding unit is sprayed onto directly and constantly. Moisture pockets are thus sprayed to destruction of sprayed open. The water can run away freely and spreads over the surface of the molten product. This water will evaporate due to the heat in the holding unit .

Water droplets that are still encapsulated in the product are pulled further apart by the various movements that have already been described.

The pumping device can be provided with a switching unit for switching between feeding the product back to the rolling device and draining the product away to the outside. After sufficient processing, the product is purified well enough and it can be removed from the holding unit. To this end, the pump can drain the product through the switching unit away to the outside instead of feeding it back to the rolling device.

A further holding unit could be provided that is arranged downstream of and in series with the earlier mentioned holding unit, wherein the further holding unit comprises heating means for heating the product that is supplied to this holding unit as well as a feeding unit that is connected to the switching unit of the earlier mentioned holding unit. By heating the product, the moisture that is still remaining can be removed from the product. It is however also possible to have a plurality of earlier

mentioned holding units placed in series. It is preferred to place a sieve above a lowest opening in the wall such that the second pump is also able to attract the product that resides in the collecting space (s). After all, the product is able to move through the lowest opening from the collecting space to the second pump.

The present invention further provides a method for purifying a polluted product. This method comprises a repetition of the steps of bringing into a rolling motion in a first direction and the simultaneous heating of the product to be purified and the collecting and feeding back of the product that has been brought into a rolling motion. As mentioned earlier, the feeding back preferably comprises the spraying of the product .

Next, the present invention will be described in more detail using embodiments that are illustrated in the

accompanying drawings, wherein:

Figure 1A and IB illustrate overviews of an embodiment of the present invention;

Figure 2 shows a rear view of the embodiment in figure 1;

Figure 3A depicts a perspective cross section of the embodiment of figure 1 and figure 3B illustrates a detailed view thereof;

Figure 4 depicts a schematic overview of a different or further embodiment of the present invention; and

Figure 5 shows a cross section of the embodiment in figure 4.

In figure 1A, one of the two walls 1 is visible that comprises plates 2, which overlap each other partly, see also figure 3A and the detailed view in figure 3B. These walls are part of the rolling device. The entity is placed in a holding unit 3 which comprises brick laid walls . The entity is arranged in the ground. Plates 2 are provided with pipe-work 5 through which a thermal liquid flows for heating plates 2.

Also visible is spraying element 6 in the form of a tubular element with openings 7. The openings have a diameter from 5 to 30 mm, more preferably from 12.5 to 17.5 mm. The openings are placed at a mutual distance which lies between 5 and 50 cm, more preferably between 10 and 30 cm, and more preferably between 15 and 25 cm.

Because of the V-shaped arrangement of walls 1 in holding unit 3, the space in holding unit 3 comprises two collecting spaces 8, 8', see figure 3A. The product, such as asphalt, can move about in holding unit 3 in substantially two different ways. Firstly, it is able to move through openings 9 in between plates 2 towards collecting space 8 or 8', see figure 3B. Another possibility is that the product moves further downward towards collecting element 10, which in figures 1A and 3A is depicted as a trough with a sieving element 11.

In the rear view in figure 2, pumps 12, 13, 14 are illustrated that carry out the attracting of the product. Here, pump 12 is connected to trough 10. An auger is disposed in trough 10 that is driven by a pump 12. Upon driving, the screw- like operation of auger 15 will ensure that the product that has reached trough 10 is moved outside of holding unit 3 where it is fed back to at least one of the collecting spaces 8, 8' by means of pipe- ork 16. Prior to feeding back to walls 1, the product is sieved once again, however in this case by a sieve having smaller openings than sieving element 11. As a result, smaller pollutions can be removed.

Pumps 13, 14 are arranged to attract the product from collecting spaces 8 and 8' and to feed it back to the rolling device by means of spraying element 6. In figures 1A and IB, glide wall 17 is shown that also is referred to as dumping wall. This wall connects to walls 1. During use, holding unit 3 is closed. With a new quantity of product to be purified, holding unit 3 is opened at the location of the glide wall 17. The product is subsequently placed on glide wall 17 after which it will glide and/or roll downwards. At this moment the product is not yet strongly heated by walls 1 and in most cases it will therefore not be liquid enough to penetrate openings 9 in walls 1. In that case, the first treatment will be the sieving by sieving element 11. However, the recently dumped product will be sprayed onto by the product that was already in the holding unit. The sieved product will be brought back from above to at least one collecting space 8, 8' by means of pump 12. The temperature in these collecting spaces is preferably more than 100 degrees Centigrade, and more preferably between 125 and 145 degrees Centigrade, and even more preferably about 135 degrees Centigrade. By means of pumps 13 and 1 , the product can be sprayed by means of spraying element 6 over walls 1. Consequently, much moisture can be extracted from the product . Also, in this way a lot of heat is supplied to the surface of the melting product, whereby the melting process occurs from the top side allowing water vapour to easily evaporate from the product .

The product will gradually be fed to holding unit 3. In this way it is prevented that too much untreated product is brought into contact with heated walls 1 as result of which explosive danger may occur. Firstly, sufficient mixing is realized of the product that is already present in holding unit 3.

In figures 4 and 5 a different or further embodiment is shown of the device according to the present invention. The most important difference with the embodiment shown earlier is that in this embodiment dumping wall 17 is heated and not inclined walls 1. Pipe-work 5 runs at a bottom side of dumping wall 17 and heats it preferably by means of direct contact. This is shown in figure 4 using dashed lines. Pipe- work 5 continues to run horizontally at a predefined height relative to the bottom of the device. Here, it is noted that pumps 13, 14 attract the product at a height in between the bottom and the pre-defined height. As a result of this arrangement, the product is forced to pass pipe-work 5 or to move near it. Because of this, the product can be heated further. The abovementioned measure can also be applied to the embodiment in figure 1.

Another benefit of this embodiment is the arrangement of sieving element 11. In this embodiment, it is placed above a lowest opening 9. As a result, pump 12 is also able to attract the heated product resulting in a good mixture between the hotter product on the lower side of the device and the cooler product on the higher side of the device. This functionality is kept even if sieving element 11 should unfortunately get clogged fully or partially by pollutions in the product. The abovemen ioned measure can also be applied to the embodiment in figure 1.

In this embodiment, spraying element 6 is arranged such that is also sprays over dumping wall 17 whereby recently dumped material is heated well from a top side, where the explosive behaviour is the most dangerous. The

abovementioned measure can also be applied to the embodiment in figure 1.

It should be clear to the skilled person that multiple modifications are possible to the embodiments of the present invention described above without departing from the scope of protection that is defined by the appended claims.