Patent Application
20230311030
The present invention relates to the field of filtering, more precisely the present invention concerns a roller based apparatus for the separation of dry matter and liquid from a medium, i.e. a roller filtration apparatus, and the method of filtering.
Separation of dry matter from liquid is known in the art. Methods such as precipitation, centrifugation and filtering are commonly used for separation purposes in a vast number of industries. The latter separation method is relevant for the present invention.
An efficient method for separating dry matter from liquid was presented in WO 03/055570 and WO 2006/002638 disclosing filtration apparatuses providing an enclosed pressure regulated separation chamber wherein a suspension is accumulated on a filter which is passed through a set of solid impermeable rollers, whereby the pressure exerted by the rollers separates liquid from the suspension. The separation chamber defined by the rollers where divided into two compartments by the filter.
This roller based principle was improved in WO 2008/131780 where a filtration apparatus based on one or more pore rollers was disclosed. A pore roller is a roller with a surface comprising pores allowing permeability for fluid, in fluid contact with a channel for guiding liquid to a filtrate outlet. Thus, the pressure exerted by the rollers guides the liquid inside the pore roller through the pores in the surface. The end products are the filtrated liquid and a dry filter cake.
Additional improvements of the pore roller based filtration principle were presented in WO 2014/198907 and WO 2017/202934. For example, WO 2017/202934 discloses a scraping element to wipe off the inside surface of a filter shell, surrounding the filter roller, and in another embodiment, WO 2017/202934 discloses use of vacuum in the pore rollers for aiding the filtering.
The documents WO 03/055570, WO 2006/002638, WO 2008/131780, WO 2014/198907 and WO 2017/202934 are hereby incorporated by reference in their entirety.
The present disclosure provides an improved roller filtration device for separation of dry matter and liquid from a medium, comprising at least one separation chamber for receiving the medium, and at least one filtrate chamber defined in cross section by press rollers and at least one pore roller, such that during separation operation, dry matter of the medium first passes between the pore roller and a press roller when transferring from the separation chamber to the filtrate chamber, and subsequently passes between two press rollers when exiting from the filtrate chamber. Hence, the separation operation implies and is occurring when the pore roller and press rollers are in rotation.
The configuration of the separation chamber and the filtrate chamber facilitates increased separation efficiency, and consequently reduced risk of rewetting, and improved uniformity and higher quality of the resulting separated dry matter and liquid filtrate. Furthermore, the configuration of the present roller filtration device provides a more simple and maintenance efficient device, thereby enabling stable, long-term operation, where parts may easily be exchanged. The configuration further facilitates a higher degree of selective separation. Hence, separation of different types of solids may be obtained.
The configuration of the separation chamber and the filtrate chamber further has the advantage that the orientation of the device, including the rollers of the device, is flexible, because the separation process does not depend on gravity. Hence, the device and the rollers may be oriented vertically, horizontally, or at any angle therein between, during operation.
A first aspect of the disclosure relates to an apparatus for the separation of dry matter and liquid from a medium, comprising:
A second aspect of the disclosure relates to a method for separating dry matter and liquid from a medium, comprising the steps of:
In a preferred embodiment, the apparatus of the first aspect is adapted for carrying out the method according to the second aspect.
In another preferred embodiment, the method includes the steps of providing the apparatus according to the first aspect, and separating the dry matter and liquid from the medium within the apparatus.
The invention will in the following be described in greater detail with reference to the accompanying drawings.
The invention is described below with the help of the accompanying figures. It would be appreciated by the people skilled in the art that the same feature or component of the device are referred with the same reference numeral in different figures. A list of the reference numbers can be found at the end of the detailed description section.
Separation Efficiency
Examples of media which are advantageously separated include suspensions from the biomass, food and beverage industries. For example, biomass waste materials in the form of manure, orange peels, and coffee grounds may be separated, and thereby upgraded into a solid fraction suitable e.g. as biogas feedstock. Also, raw materials for food/beverage products, may be upgraded into a higher value product. For example juice comprising fruit pulp or sludge, crushed grape pulp for wine, mask for beer, eatable oils suspensions, and yeast and bacteria containing suspensions may be separated, and thereby upgraded into a product with a lower concentration of solids, e.g. a lower concentration of pulp or microorganisms. Another example of upgraded separated products include orange peels, where it is advantageous to separate the white solid parts (albedo) from the orange parts (flavedo) due to different application purposes. A further example of upgraded separated products include mango or mango waste materials, where it is advantageous to separate the different phases: the free liquid juice phase, the partly solid flesh/pulp, the skin/peel, the husk, and the seed/stone. Further examples include beans and apples.
A medium for separation comprises a mix of one or more solid and liquid parts, and the medium may further be characterised as a suspension, dispersion, paste, and/or slurry depending on the dry matter content, the ratio between solid and liquid parts, and the stability of the solid particles within the liquid part. The separation into the corresponding solid parts and liquid parts may be obtained by one or more filtration steps. However, complete separation is difficult to obtain. Hence in practice, the separated solid fraction, or the dry filter cake, will comprise both solid and liquid parts, but with a reduced content of liquid compared to the original mixture, and the separated liquid fraction, or the filtrated liquid, will comprise both solid and liquid parts, but with a reduced content of solid compared to the original mixture.
The separation efficiency, or the filtration efficiency, will depend on the starting medium and the separation method. For example, the size of the solid particles within the mixture in combination with the size of the filter mesh openings, will determine the filtering efficiency. Complete separation implies that the separated liquid fraction, also referred to as the filtrate or filtrated liquid, is a liquid fraction essentially void of solid substances. Similarly, complete separation implies that the separated solid fraction, also referred to as the dry filter cake, is essentially void of liquid parts.
By use of the device according to the present disclosure, a surprisingly high separation efficiency may be obtained. In an embodiment of the disclosure, the separated solid fraction has a dry matter content of at least 50 vol %, such as above 55, 60, 65, 70, 75, 80, 85, 90, 95, or 97 vol %.
The separated solid fraction will be prone to rewetting. Thus, following the separation steps, the separated solid fraction and liquid fraction are advantageously kept physically apart. Rewetting of the solid fraction will correspond to a decrease in the separation efficiency.
For efficient separation, the separation method, e.g. the speed of press rollers and pore rollers, is adapted to the starting medium. Hence, the apparatus advantageously comprises a data processing unit configured for receiving input on the medium received within the separation chamber, e.g. via a communication device, such as a wireless device which may be a tablet, smart phone, or a laptop.
In an embodiment of the disclosure, the apparatus comprises a data processing unit configured for receiving input on the received medium, and optionally controlling the rotation means.
A further aspect to the separation efficiency is the separation selectivity. For example, a medium for separation may comprise a mix of two or more types of solid parts and liquid parts, such as a orange peels comprising white solid parts (albedo), orange coloured parts (flavedo), and liquid juice, or a mango comprising seed, husk, juice, flesh, and peel. The configuration of the separation method may hence promote a higher concentration (or selectivity) of e.g. the white solid parts in the separated solid fraction.
Chamber Configuration
Feed Inlet
The device, or apparatus, comprises a separation chamber 3 adapted for receiving the medium to be separated. The medium may for example be supplied to the separation chamber via a feed inlet 4, which may further be adapted to facilitate a continuous or a batch controlled feed of the media to the separation chamber. A continuous feed of medium via the feed inlet may be obtained by use of a transport unit, such as a screw conveyor. For example the feed inlet may be a tubular structure as seen in
In addition, or alternatively, the feed may be obtained by gravity.
In an embodiment of the disclosure, the separation chamber comprises a feed inlet. In a further embodiment, the feed inlet comprises a transport unit, such as a screw conveyor.
The feeder advantageously generates an overpressure through the feed inlet and into the separation chamber 3, which thereby may accelerate the separation rate. The overpressure is e.g. generated by gravity and/or the rate/speed of the grinder unit and/or transport unit, e.g. the rotation speed and/or shape of the screw conveyor or transport spiral.
Grinder Unit
The present disclosure further relates to a grinder unit. A grinder unit is configured for producing a grinded product, i.e. to cut or comminute the solid parts of the feed into a smaller and more uniformly sized particles, and/or to deagglomerate particle agglomerates, e.g. to split apart smaller particles adhering to the surface of larger particles. The comminution may for example be obtained using cutting knives, such as rotating knives, ball milling, and roller mills.
The presently disclosed separation device may be used for separating different types of media into dry matter and liquid, where the media may comprise solids of very different particle sizes and shapes. To ensure a uniform separation efficiency, the separation chamber and/or the feed inlet are advantageously in fluid communication with the presently disclosed grinder unit.
In an embodiment of the disclosure, the separation chamber and/or the feed inlet is in fluid communication with the grinder unit. In a further embodiment, the grinder unit is selected from the group of: rotating knives/blades, ball mills, and roller mills.
To improve the simplicity and cost efficiency of the device, the grinder unit is advantageously a combined transport unit and grinder unit. For example, the transport unit may be a modified screw conveyor, which acts as a grinder unit due to a blade configuration or blade rotation similar to a push lawn mower. Thus, the grinder unit may be simply detachably mounted in the device, e.g. by a clamp, such that it is easily detached for maintenance, and reattached after maintenance. The grinder unit may further easily be replaced with a cleaning unit, comprising a feed of cleaning means, such as an acidic or basic solution or fluid.
The presently disclosed grinder unit may be used separately, as well as in combination with the separation apparatus of the present disclosure, or in combination with other apparatuses.
In an embodiment of the disclosure, the transport unit is further a grinder unit, such as a push lawn mower blade grinder. In a further embodiment, the transport unit comprises a longitudinal/elongated tube.
The transport unit advantageously comprises a liquid inlet and/or outlet. For example, efficient grinding may require a certain amount of liquid present. Hence, additional liquid may be supplied to the feed through a liquid inlet, or removed from the feed through a liquid outlet. Optionally, the liquid inlet and liquid outlet is the same, and only differs by the direction of the liquid flow. The direction of the liquid flow may be controlled by any known flow regulation means. For example, liquid will flow out of the feed if the pressure at the liquid inlet/outlet is below the pressure at the feed unit, e.g. if the pressure at the outlet is negative relative to the feed, such as vacuum. To ensure only liquid flows through the liquid inlet and/or outlet, the inlet/outlet may comprise a filtering unit.
The longitudinal tube of the transport unit advantageously comprises the liquid inlet and/or outlet and filtering unit. Hence, the pressure at the liquid inlet/outlet may be easily controlled, and e.g. be set to vacuum.
In an embodiment of the disclosure, the transport unit comprises a liquid inlet and/or outlet. In a further embodiment, the liquid inlet and/or outlet is configured to have a relative negative pressure, such as vacuum.
As seen in
In an embodiment of the disclosure, the grinder unit comprises a cylindrical filter configured as liquid outlet.
The efficiency of the initial separation step will depend on several factors, e.g. if the liquid outlet or the interior cylindrical filter is configured to have a relative negative pressure, as well as the pressure difference across the filter, the type of filter, and the pore size or mesh size of the cylindrical filter. The more efficient the initial separation step, the more efficient the overall separation of the apparatus. Highly efficient initial separation is observed for ceramic filters, such as carbide filters, e.g. silicon carbide (SiC), which due to their high mechanical strength allows for high feed rates, and high feed pressures, as well as high pressure differences across the cylindrical filter. The ceramic filters further has the advantage that they are self-supporting, and may withstand high radial pressure from a rotation mean, such as a drum motor.
In an embodiment of the disclosure, the cylindrical filter is a ceramic filter, such as a silicon carbide (SiC) filter with a pore size between 0.01 μm-2 cm, more preferably 0.01-0.5 μm, more preferably between 0.1-0.3 μm, such as 0.2 μm.
To reduce the risk of clogging along the cylindrical filter, and for efficient grinding of the feed material, the cylindrical filter is advantageously rotatable, and the grinder unit further comprises one or more blades 11.3 extending radially outwardly from the cylindrical axis and in a direction along the cylindrical axis. The blades may be physically separated from the cylindrical filter, as for the push lawn mower configuration in
In an embodiment of the disclosure, the cylindrical filter is adapted to be stationary and/or rotatable in both directions around the cylindrical axis. In a further embodiment of the disclosure, the apparatus comprises one or more blades extending radially outwardly from and in a direction along the cylindrical axis.
For efficient grinding and pressure distribution of the feed within the grinder, the one or more blades advantageously extend along the cylindrical axis or the cylindrical filter in a helical pattern, as illustrated in
In an embodiment of the disclosure, the one or more blades extend along the cylindrical axis in a helical pattern. In a further embodiment, the apparatus comprises between 2-8 blades, preferably 4 blades. In a further embodiment, the blades are adapted to be rotatable in both directions around the cylindrical axis.
For further efficient grinding and pressure distribution, the grinder unit further comprises an outer grinder filter 11.2 surrounding the blades, such that the revolving blades are crushing and grinding the feed material by the blades as well as crushing and grinding the feed material against the outer filter, as seen in
In an embodiment of the disclosure, the grinder unit comprises an outer filter surrounding the blades. In a further embodiment, the outer grinder filter is a ceramic filter with a pore size between 0.2 μm-2 cm, preferably between 0.5 μm-5 mm, or between 1-10 mm, more preferably between 3-7 mm, such as 5 mm.
Both the cylindrical filter 11.1 and the outer grinder filter 11.2 may be configured to have a relative negative pressure, such as vacuum, at the interior filter side or inner lumen to improve the initial separation. This may be obtained due to the pore size or mesh size of the filters. Further, this may for example be obtained as illustrated in
In an embodiment of the disclosure, the cylindrical filter and/or the outer grinder filter is configured to have a relative negative pressure, such as vacuum.
The grinder unit, including the cylindrical filter and the outer grinder filter, are advantageously detachably attached to the housing or the end plates, e.g. by use of fastening means such as clamps 20, as illustrated in
In an embodiment of the disclosure, the rollers, and/or grinder, and/or scraping elements are detachably attached to the housing or the end plates, such as by use of clamps, optionally in combination with one or more slidable adjusters.
For further efficient grinding and pressure distribution, the grinder unit advantageously is or comprises a pre-grinding unit, as illustrated in
In a further embodiment of the disclosure, the transport unit is a combined grinder unit and transport unit, in extension of each other, as illustrated in
In
The transport unit is in extension of the grinder unit, and comprises similar or identical spiral or helical blades, e.g. screw conveyor blades, in linear extension of the grinder unit blades, for transporting the flow mainly radially away from the axis and towards the wet sieve cutter boundary surrounding the screw conveyor. Similarly to the grinder unit, the transport unit may comprise a cylindrical filter 11.1 and an outer grinder filter 11.2, as illustrated in
The rotation, transport unit and/or grinder unit may be driven by a motor by one or more shafts 25, as illustrated in
Advantageously, the shafts 25A and 25B are adapted to be independently stationary and/or rotatable in both directions around the cylindrical axis. By controlling, and particularly changing, the rotation rates and rotation direction of the shaft sections, and optionally the filters, the shear forces within the grinder unit and transport unit may be independently controlled, as well as the residence time of the feed within each of the units. Hence the initial separation occurring within the grinder and transport unit may be improved. For example, the rotation speed may be controlled by rotating the left part of the shaft 25A in
As illustrated in
The feed 4A which enters the separation chamber 3, may be discharged from the tubular grinder/transport unit in the radial direction, whereby it enters the separation chamber through the surrounding tubular wet sieve cutter 26, as illustrated in
The configuration further enables that any solids 4B and liquids 4C, which are unwanted for entry into the separation chamber (e.g. the seeds from a mango, or solid impurities, or tools, which have entered the feed by mistake, and liquids), may be separated by the wet sieve cutter, blades, and vacuum, and discharged at separate outlets, as illustrated in
Chambers
The device of
In an embodiment of the disclosure, the separation chamber is defined in cross section by press rollers and the at least one pore roller. In another embodiment, the separation chamber is defined in cross section by a housing, the at least one pore roller, and two or more press rollers.
From the separation chamber 3, a medium may pass between a set of abutting press roller and pore roller into the filtrate chamber 5. For example, the medium passes between an abutting press roller and pore roller, when the rollers are in rotation as exemplified by the arrows in
The first solid fraction may subsequently be passed between a set of abutting press rollers 1. The interface between the abutting press rollers is configured as a second filtration boundary 9, separating the first solid fraction into a second liquid fraction and a second solid fraction. The second liquid fraction may be squeezed back into the filtrate chamber 5, whereas the second solid fraction may pass between the press rollers and into the dry matter outlet 7. Thus, at the second filtration boundary 9 the first solid fraction, or first dry filter cake, may be further separated into a second liquid fraction, or second filtrated liquid, which is restricted to the filtrate chamber 5, and a second solid fraction, or second dry filter cake, which is transferred to the dry matter outlet 7, and where the second solid fraction has a lower liquid content than the first solid fraction.
It follows that any number and combination of press rollers 1 and pore rollers 2 may be applied. Increasing the number of pore rollers 2, has the advantage of increasing the separation output capacity of the apparatus, since it corresponds to increasing the area of the first filtration boundary 8. Hence, a higher production rate of the first liquid fraction may be obtained.
Increasing the number of press rollers 1 also has the advantage of increasing the separation output capacity of the apparatus, since it corresponds to increasing the area of the second filtration boundary 9. Hence, a higher production rate of the second solid fraction may be obtained. Furthermore, by increasing the number of press rollers 1, a separation chamber defined in cross section by at least some of the press rollers and the at least one pore roller may be obtained, as illustrated in
A separation chamber defined by press rollers and pore rollers has the advantage of reducing the amount of gaskets needed, and further simplifying the device and the maintenance of the device. For example, by simply removing or translating one or more press rollers, the pore rollers, feed inlet and grinder are easily accessed and exchanged, as seen in
To improve the cost-efficiency and simplicity of the device, the number of parts, including the number of rollers, are advantageously kept at a minimum. A high separation output capacity, in combination with a minimum of rollers, is seen for the apparatus having the roller configurations shown in
In an embodiment of the disclosure, the apparatus comprises at least three press rollers. In another and/or further embodiment of the disclosure, the separation chamber is defined in cross section by press rollers and the at least one pore roller. In a further embodiment, the apparatus comprises at least six press rollers, and at least two pore rollers.
The diameter of the at least one pore roller is advantageously sufficiently smaller than the diameters of the press rollers, whereby a simple and compact apparatus may be obtained.
In an embodiment of the disclosure, the diameter of the at least one pore roller is at least 50% smaller than the diameter of the press rollers, more preferably at least 60% or 70% smaller, and most preferably at least 75% smaller.
The first solid fraction is transferred into the filtrate chamber 5, and then subsequently passed between the press rollers to exit the filtrate chamber. To further aid the movement of the solid fraction between the press rollers, and preferably to aid the movement of selected solid parts of solid fraction, the filtrate chamber advantageously comprises a fluid inlet for introducing a predefined gas, e.g. air, or liquid into the filtrate chamber. Hence, the supply of gas, air, and/or liquid into the filtrate chamber may be regulated by any known means such as pumps and/or valves.
In an embodiment of the disclosure, the filtrate chamber comprises a fluid inlet.
Sealant
The press rollers may comprise gaskets or sealants around the ends of the rollers. Alternatively, or additionally, the housing may comprises gaskets and/or sealants, such that the separation chamber is sealed.
In an embodiment of the disclosure, the apparatus comprises a housing at least partly surrounding the rollers, wherein the housing walls comprise a sealant.
A simple housing with fewer parts, includes a housing comprising two end plates 24 abutting at least the press roller ends, as illustrated in
In an embodiment of the disclosure, the housing comprises two end plates abutting the roller ends. In a further embodiment, the end plates are configured as sealant for the roller ends.
The surface structure or roughness, including the depression and elevated platform of the end plates, may be obtained by milling a stainless steel plate, or milling a polymer plate, such as polyethylene (PE). The structured end plates may be attached, e.g. bolted, to a supporting back plate, for improving the mechanical structure and for easier manufacture. The design of the end plates further has the advantages of easy service and maintenance, including cleaning without disassembly, as well as reduced friction upon rotation of the rollers, thereby improving the performance of the rotation means, e.g. a driving motor.
In an embodiment of the disclosure, the end plates comprise a protruding platform for sealingly engaging a section of the roller end circumference. In a further embodiment, the end plates comprise a polymer, such as polyethylene (PE), and/or stainless steel.
Due to the sealingly engagement between the protruding platform and the rollers upon rotation, the protruding platform may be prone to wear. As the size of the protrusion is reduced, the sealing engagement is reduced, and there is a risk of leaks between the separation chamber and the surroundings. Hence, advantageously, the apparatus comprises a sensor for detecting changes in the dimensions of the sealant, e.g. the height of the protrusion.
In an embodiment of the disclosure, the apparatus comprises a sensor for detecting changes in the dimensions of the sealant.
The end plates configured as sealant for the roller ends, provide a simple and efficient sealant for the separation chamber. Thus, the apparatus of the disclosure may be oriented in any orientation during operation, e.g. the device and the rollers may be oriented vertically, horizontally, or at any angle therein between. In addition to the feed material pressure, the operation may be enhanced by using hydrostatic pressure.
In an embodiment of the disclosure, the rollers are configured to be oriented horizontally.
For assembly and disassembly, e.g. for service and maintenance of the apparatus, the sealants are advantageously detachably attached to the end plates, the rollers, and/or the housing, e.g. by use of fastening means such as clamps. Further advantageously, the fastening means include a spring force, such that a tight sealant configuration is ensured even when the dimension of the sealant changes during operation due to wear. This further facilitates digital monitoring and control of the sealants.
Operation
When the press rollers and pore rollers are rotating, the medium fed to the separation chamber will be separated by the device. Due to the rotation, the medium fed to the separation chamber 3 will first pass between a set of abutting press roller and pore roller, i.e. the first filtration boundary 8. At this boundary, liquid is squeezed out of the passing medium, and into the interior of the pore roller. Advantageously, the interior of the pore roller may function as pore roller liquid outlet 6, such that the risk of rewetting is reduced. Thus, at the first filtration boundary the passing media is separated into a first liquid fraction or a first filtrated liquid, and a first solid fraction or a first dry filter cake, where the first liquid fraction is transferred into the interior of the pore roller, and the first solid fraction is transferred into the filtrate chamber 5.
Due to the rotation, the first solid fraction is subsequently passed between a set of abutting press rollers 1. The interface between the abutting press rollers is configured as a second filtration boundary 9, separating the first solid fraction into a second liquid fraction and a second solid fraction. The second liquid fraction is squeezed back into the filtrate chamber 5, due to the impermeable nature of the surface of the abutting press rollers, whereas the second solid fraction passes between the press rollers and into the dry matter outlet 7. Thus, at the second filtration boundary the first solid fraction, or first dry filter cake, is further separated into a second liquid fraction, or second filtrated liquid, which is restricted to the filtrate chamber, and a second solid fraction, or second dry filter cake, which is transferred to the dry matter outlet, and where the second solid fraction has a lower liquid content than the first solid fraction.
The two separation steps provides increased separation efficiency including reduced risk of rewetting the separated solid fractions, and a second solid fraction with a surprisingly high dry matter content, such as at least 50 vol %, may be obtained.
In an embodiment of the disclosure, a method for separating dry matter and liquid from a medium is provided, comprising the steps of:
Advantageously, the method is carried out in the apparatus of the present disclosure, and vice versa, the apparatus of the present disclosure is advantageously adapted for the disclosed separation method.
A roller is inherently adapted for rotating. The rotation of the press rollers and pore rollers may be obtained by one or more of the rollers being actively driven, e.g. by a motor. The actively rotating roller(s) may then drive the rotation of the neighbouring rollers, and the neighbouring's neighbour rollers, due to the rollers being abutting. Hence, an actively driven roller may drive one or more abutting neighbouring passive rollers, where a passive roller is not actively driven, but merely adapted for rotating, and where the rotation may be actuated by an abutting roller that is in rotation. The actively driven roller may further actuate rotation of the passive neighbouring's further passive neighbours, which are abutting. Thus, an actively driven roller may initiate a chain reaction of rotating passive rollers in the manner of a domino effect. For efficient and synchronous rotation, preferably at least one press rollers is configured as an active roller. The active press rollers are further advantageously rotated by a motor, which is a geared motor, such as a drum motor comprising planet gears. Hence, efficient and adjustable rotation may be obtained. A drum motor further has the advantage of being cost efficient, robust, clean, and maintenance friendly.
In an embodiment of the disclosure, at least one press roller is an active roller, and optionally the at least one active press roller is rotated by a motor, optionally a geared motor, such as a drum motor.
To further improve the separation efficiency, two or more abutting rollers are advantageously active rollers, and/or adapted to rotate at different speed, such that shear forces occur at the filtration boundary between the abutting rollers.
In an embodiment of the disclosure, at least two rollers are active rollers, and preferably wherein the rollers are adapted to rotate at different speed.
Hence, the apparatus for the separation of dry matter and liquid from a medium, comprises:
The operation of the apparatus may advantageously be partly or fully digitalized. For example, the rotation direction and rates of the grinder unit, transport unit, press rollers and pore rollers may be controlled via a user interface. Further advantageously, the user face includes controls for the grinder unit parameters, such that a certain cutting degree is obtained, e.g. a certain uniform sized particles or agglomerates. In addition the user face advantageously includes controls for the flow and directions of gasses and liquids within the system, such that a certain dry matter content may be requested at the feed, e.g. by adding fluids to the feed.
Press Roller
A press roller is a roller with a continuous and/or impermeable surface of the roller area. A press roller can be a solid roller or can comprise an inner small roller with a corresponding larger outer press shell arranged around the inner roller thereby enclosing the inner roller. The continuous and/or impermeable surface of the press roller can be provided in for example rubber, plastic, polymer or metal, such as stainless steel and nylon, or a mix thereof. For example, an embodiment of a press roller may include a core of metal, such as steel and an outer layer of rubber, or a core made from hard rubber and an outer layer made from rubber being softer than the core rubber. The shore value of the rubber may be between 20 and 95, such as between 60 and 90.
The continuous and/or impermeable surface of the press rollers entail that only the separated solid fraction will pass between abutting press rollers, or between abutting press roller and pore roller. The separated liquid fraction will, due to the pressure exerted by the rollers, either be guided into the interior of the pore roller via the pores on the surface, or be squeezed back away from the abutting rollers.
To aid the movement of the solid fraction between the press rollers, one or more of the press rollers advantageously comprises a non-smooth surface, i.e. a part of the roller surface has an irregular surface, such as a grooved surface. The grooved surface may further comprise regularly spaced grooves, such that the roller appears as gear shaped as seen in cross section.
In an embodiment of the disclosure, at least one of the press rollers comprises an irregular surface. In a further embodiment, at least one of the press rollers comprises a grooved surface. In a further embodiment, at least one of the press rollers comprises a surface with regularly spaced grooves, optionally wherein the surface is gear shaped.
To retain that it is still mainly the solid fraction, which is permitted passage between abutting rollers, two abutting rollers advantageously comprises matching surfaces, e.g. shaped as meshing gears. Thus, the at least one press roller comprising an irregular surface is abutting a roller, i.e. a press roller and/or pore roller, with a matching irregular surface. Alternatively, the matching irregular surfaces are configured to be synchronous, such that they are non-meshing gears, but instead a groove of the first roller abuts a groove of the second roller, and a protrusion of the first roller abuts a protrusion of the second roller. This way an improved contact force between the abutting rollers, and particularly the abutting protrusions, may be obtained.
A non-smooth surface of the press rollers further has the advantage that the separated dry matter may be easily removed from the apparatus after the separation operation. For example, the separated dry matter which have passed two press rollers with an irregular surface may be easily released to the housing without the use of an external scraping element. The separated dry matter may further be removed from the housing by the pressure within the housing, and/or snailed out by use of a scraping element, such as a helix shaped scraping element, and/or snailed out by the pattern of the irregular surface, e.g. a teeth patterned surface.
In an embodiment of the disclosure, at least two of the press rollers comprises an irregular surface. In a further embodiment, the at least one press roller comprising an irregular surface is abutting a roller with a matching irregular surface. In a further embodiment, the at least one press roller comprising an irregular surface is abutting a press roller with a matching irregular surface. In a further embodiment, the matching irregular surfaces are meshing gears or non-meshing gears.
To further aid the movement of the solid fraction between the press rollers, as well as to aid the movement of selective solid fractions between the press rollers, and further away from the press rollers, the press rollers advantageously comprise a temperature regulating element. For example, the press rollers may comprise a heating/cooling element, such as a jacket 16.1, in thermal communication with a part of the press roller circumferential surface, whereby the temperature of the press roller is controlled, and hence the temperature of the solid fraction exiting the filtrate chamber can be regulated and controlled. For efficient thermal communication, at least a part of the surface of the press roller comprises metal, whereby the solid fraction may be cooled or heated when exiting the filtrate chamber.
In an embodiment of the disclosure, the at least one press roller comprises a temperature regulating element. In a further embodiment, the temperature regulating element is
Pore Roller
A pore roller, also referred to as a filter roller, is a roller with a liquid permeable surface of at least a part of the roller area in contact with the press roller. An example of a filter roller is a pore roller disclosed in for example WO 2008/131780 and WO 2014/198907 where fluid is sucked through pores extending transversely, or radially, in the roller.
A filter roller can also comprise a filter roller with a recess in the surface and a filter shell enclosing the filter roller, the recess and the filter shell thereby creating a narrow filtration boundary. A filter roller can also comprise a small inner roller enclosed by a larger filter shell. In case of a filter shell it is the surface of the filter shell that is permeable.
The at least one pore roller is a roller comprising pores extending from the surface of the roller to at least one channel extending in said roller, preferably extending axially in said roller. Thus, the channel extending axially in the roller may function as pore roller liquid outlet 6. The size of the pores is preferably adjusted to a particle size of the dry matter to be separated. Thus, in one embodiment the pore roller has a pore size of at the most 5 mm, such as at the most 4 mm, for example at the most 3 mm, such as at the most 2 mm, for example at the most between 1 mm, such as at the most 75 μm, for example at the most 50 μm, such as at the most 25 μm, for example at the most 10 μm, such as at the most 1 μm, for example at the most 0.5 μm, for example at the most 0.1 μm, for example at the most 0.05 μm, for example at the most 0.01 μm. The size of the pores may be substantially identical along the radial direction of the roller, or the pore may extend into a wider groove when the pore reaches the outer surface of the roller or the inner surface of the roller in the channel.
The pore roller may be made from any suitable material, such as metal, rubber, plastic, including nylon, ceramics, and glass. To reduce material costs and weight of the device, the pore roller may be hollow, for example shaped as a hollow cylinder. Alternatively, the pore roller may have an outer part comprising the pores, which is made from a first material, such as metal, rubber, plastic, including nylon, ceramics, and/or glass, and an inner core part made from a second material, such as metal, rubber, plastic, including nylon, ceramics, and/or glass. It was found that a robust pore roller with efficient filtration may be obtained by use of pore roller shaped as a hollow cylinder, and comprising ceramic carbide, such as silicon carbide (SiC).
In an embodiment of the disclosure, the pore roller comprises a hollow cylinder, optionally comprising silicon carbide (SiC), and preferably wherein the hollow cylinder consists of silicon carbide.
The pore roller may be connected to means for pressurizing the system or pressure control means, for example so that a relative positive or negative pressure, such as vacuum, may be applied to the one or more channels of the pore roller in order to pressurize the filtering system. Hence, the interior of a pore roller may be pressurized.
In an embodiment of the disclosure, the pore roller is configured for comprising a relative negative pressure, such as vacuum.
Upon rotation of the pore roller, the filtrated liquid located near the surface area of the pore roller may contact the separated first solid fraction, and consequently cause rewetting of the solid fraction. As mentioned above, a negative pressure within the pore roller may aid in removing the filtrated liquid from the surface area of the pore roller to the liquid outlet.
In addition, or alternatively, a hollow pore roller may further comprise a scraping element for scraping or wiping the interior surface of the pore roller, thereby aiding in transferring the filtrated liquid away from the surface area and to the liquid outlet. The scraping element may be in the form of wiper, such as a windscreen wiper, or a rotating roller with a grooved surface. Alternatively, the scraping element is a scraper protrusion, e.g. a lip mounted on a rod, e.g. a tolerance rod, allowing for internal scooping/scraping as the rod is revolved or rotated.
In addition, or alternatively, the scraping element 23 may be located in contact with the part of the pore roller within the filtrate chamber, as illustrated in
Further advantageously, the scraping element is in thermal communication with a temperature regulating element, such that the temperature of the removed dry matter may be controlled and regulated by removing or supplying thermal energy.
To further reduce the risk of rewetting the dry filter cake, or the first solid fraction, after it has passed the abutting pore roller and press roller, the separated filtrated liquid located near the surface area of the pore roller, is advantageously guided away from the surface area of the pore roller as fast as possible. For example, if the pore roller is a hollow cylinder, a part of the filtrated liquid will be located inside the pores at the surface and at the interior surface of the hollow cylinder.
In an embodiment of the disclosure, the pore roller comprises a scraping element, adapted for scraping at least a part of the interior and/or exterior surface of the hollow pore roller. In a further embodiment the pore roller comprises an inner scraping element, adapted for scraping at least a part of the interior surface of the hollow pore roller, In a further embodiment, the scraping element is selected from the group of: wiper, a rod comprising a protrusion, and a roller with a grooved surface.
To ensure efficient separation and removal of the filtrated liquid, the pore roller advantageously comprises a pore roller liquid outlet 6, from where the filtrated liquid is transferred away from the pores and pore roller channel(s). Optionally, the pore roller liquid outlet comprises a pore roller liquid outlet chamber 13, as illustrated in
In an embodiment of the disclosure, the pore roller comprises a pore roller liquid outlet. In a further embodiment, the pore roller liquid outlet is in fluid communication with the grinder unit.
To facilitate a hollow pore roller, the pore roller is advantageously a passive roller, where the rotation is driven by the abutting rollers. For efficient rotation, the passive roller is advantageously rotated by two abutting active press rollers. Thus, no rotation axis or shaft is needed for a passive roller. A passive pore roller further has the advantage of providing higher shear forces at the filtration boundary.
Alternatively, the pore roller may be an active roller comprising rotation means, e.g. a motor, configured to be placed externally to the pore roller, e.g. placed at one of the longitudinal ends of the roller. For example, the external motor may be a drum motor. The rotation means may further be configured to be passively operated, e.g. via a free run.
In an embodiment of the disclosure, the pore roller is a passive roller. In another embodiment, the pore roller is an active roller comprising rotation means configured to be placed externally to the pore roller. In a further embodiment, the rotation means comprise a free run.
External Scarping Element
The external surface of filters such as the cylindrical filter, the outer grinder filter, and the pore rollers, may be clogged during operation. Similarly, the external surface of the press rollers may risk adhesion of materials. To reduce the risk of clogging and material adhesion, the rollers and/or filters advantageously comprise an external scraping element 23, as illustrated in
In an embodiment of the disclosure, one or more of the rollers and/or filters comprise an external scraping element, adapted for scraping at least a part of the exterior surface of the roller and/or filter. In a further embodiment, the external scraping element is selected from the group of: a spindle, an auger, a static scraper, a roller with a grooved surface, bristles and brushes, optionally wherein the external scraping element is placed adjacent to an end of the roller(s).
Items
The presently disclosed may be described in further detail with reference to the following items.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20183703.6 | Jul 2020 | EP | regional |
This application is the U.S. National Stage of PCT/EP2021/068371 filed on Jul. 2, 2021, which claims priority to European Patent Application 20183703.6 filed on Jul. 2, 2020, the entire content of both are incorporated herein by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/068371 | 7/2/2021 | WO |
