WO2011087350A1

WO2011087350A1 - Bitumen packaging

Info

Publication number: WO2011087350A1
Application number: PCT/MY2010/000009
Authority: WO
Inventors: Bin Mohd Yousf Zaidin; Wai Keong Lam
Original assignee: First Bitumen Sdn Bhd
Priority date: 2010-01-13
Filing date: 2010-01-13
Publication date: 2011-07-21

Abstract

The present invention provides a polymer bag of a bitumen packaging. The polymer bag comprises 15-25% of ethylene vinyl acetate (EVA); and 75-85% of low density polyethylene (LDPE). Preferably, the polymer bag is dissolved into the bitumen when the polymer bag is heated up together with the bitumen to a melting temperature.

Description

BITUMEN PACKAGING

Field of Invention

The present invention relates to bitumen. In particular, the present invention relates to a system and method for packaging bitumen.

Background

Conventionally, bitumen is shipped from one place to another in a highly viscous form. To maintain the bitumen in the viscous form, the bitumen is continuously heated to about 110-120 degree Celsius throughout the journey. Such continuous heating can be translated to a great amount of energy, which is extremely unfriendly to the environment.

In light of the above issue, there exists a method of maintaining bitumen in a semisolid form for handling and storage. In order to do that, the bitumen is required to be cooled to a lowered temperature. It is understood that water cannot come in direct contact with hot bitumen (around 110-120 degree Celsius) as it will cause water to boil generating steam, which could be a safety hazard while handling the bitumen. Therefore water cooling is applicable with a jacketed layer to separate the water from the hot bitumen. The jacketed layer also acts as a heat conducting medium to transfer the heat from the bitumen to the water. An example of such jacketed layer includes a pipe. However, bitumen closest to the surface of the pipe is better cooled than the bitumen at the inner core section of the pipe. It causes a variance in the viscosity of the bitumen which would cause irregular flow speeds.

One solution to address the problem is to provide a series of jacket tanks with water flow acting as a heat exchange. However the number of tanks needed to cool the volumes of bitumen to make this process commercially not viable, and it is cost prohibitive, energy and space inefficient.

One known such form bitumen available in the market is BituBale®. The bitumen is cooled by water circulating in a jacketed tank filled with bitumen and continuously agitated by a piston pump moving a serried of perforated fins inside the tank. Upon cooling to the desired temperature the bitumen is then pumped into a polymer tube and filled. After filling it is then rolled into a bale shaped form and outer wrapped by a stretchable material.

One can also use the pipe and water-cooled method of cooling of bitumen. However, such cooling method has a disadvantage of inconsistent flow. Generally, the bitumen flows in the core of the pipe is different than those closer to the wall of the pipe, thereby causing differences in viscosity of bitumen inside the pipe. It accordingly results variable flow speeds within the pipe too. Therefore, temperature consistency of the outflow bitumen and stability of cooling temperatures is not controllable. Further, such temperature inconsistency would cause the pipe to clog in time.

Batch cooling can also be used by slow agitation of bitumen cooled to the desired temperature before packing but the low capacity due to time needed to cool makes it not commercially viable. The method significantly slows down and reduces the total packing volume over time. One can also argue the fact that a series of multiple cooling tanks can be made to cool in larger batches but the cost would be significantly higher to fabricate such a system and also energy requirements would be higher.

Therefore, there is an objective of the present invention to turn the traditional hot liquid bulk transport or environmentally damaging steel drum packing of bitumen into a clean, safe, recyclable, cost effective handling and usage of bitumen with minimal wastage.

Summary

In one aspect of the present invention, there is provided a bitumen cooling tower comprises a supply pipe for supplying and dispensing bitumen; means for forming a cascade of bitumen curtain as the bitumen is flowing downwardly in the cooling tower; a collection bin for collecting bitumen flow; and one or more fan oriented to forced-air cool the cascade of bitumen curtain. In one embodiment, the cascade of bitumen curtain free-falls from the means as it forms the cascade of bitumen curtain.

In another embodiment, the means for forming the cascade of bitumen curtain defines a flat incline platform, wherein the bitumen flows across the flat incline platform as it downwardly flow into the collection bin.

In a further embodiment, the cooling tower further comprises a platform having an edge on one side, the platform is positioned below the supply pipe, wherein the bitumen dispensed on the platform flows across the platform and falls at the edge of the platform to form a cascade of bitumen curtain. The platform may be downwardly inclined towards the edge. It is also possible that the platform comprises a weir that forms a reservoir behind the weir, wherein the weir regulates the flows of the bitumen to form the cascade of bitumen curtain.

In another alternative embodiment, the other side of the weir comprises a downwardly inclined surface. It may further comprise one or more dampers, arranged below the platform.

In yet a further embodiment, the means for forming the cascade of bitumen curtain is defined on a spout of the supply pipe dispensing the bitumen.

In another aspect of the present invention, there is also provided a method of cooling bitumen. The method comprises dispensing bitumen into a cooling tower; forming a cascade of bitumen curtain in the cooling tower; and forced-air cooling the cascade of bitumen curtain. The cooling tower may be the aforesaid cooling tower.

In yet a further aspect, the is provided a method of packaging bitumen comprises dispensing bitumen into the aforesaid cooling tower cooling the bitumen with the cooling tower; dispensing bitumen into individual polymer bag; sealing the individual polymer bag; sealing the individual polymer bag into a box; and sealing the box. In one embodiment, the method further comprises pumping the cooled bitumen into another or more cooling tower for cooling to a desired temperature.

In another aspect of the present invention, there is provided a polymer bag of a bitumen packaging. The polymer bag comprises 15-25wt% of ethylene vinyl acetate (EVA); and 75-85wt% of low density polyethylene (LDPE). The polymer bag is dissolved into the bitumen when the polymer bag is heated up together with the bitumen to a melting temperature.

In one embodiment, the polymer bag comprising 15wt% of the EVA. The polymer bag may futher comprise 85wt% of the LDPE. It is also possible that the polymer bag is sized to amount about 0.2 to 0.3 wt% of the bitumen packaging when it is dissolved in the bitumen. The polymer bag may be about 0.4mm thick. Further, the bag may be fabricated into a generally rectangular-shaped bag.

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Brief Description of Drawings

This invention will be described by way of non-limiting embodiments of the present invention, with reference to the accompanying drawings, in which

FIG. 1 illustrates a block diagram of a process flow of a production line of bitumen packaging in accordance with one embodiment of the present invention;

FIG. 2A illustrates a cooling tower in accordance with one embodiment of the present invention;

FIG. 2B illustrates a platform of the cooling tower in accordance with another embodiment of the present invention;

FIG. 2C illustrates a cross sectional view of the cooling tower in accordance with an alternative embodiment of the present invention; and

FIG. 3 illustrates a schematic diagram of part of the conveying system in accordance with one embodiment of the present invention. Detailed Description

In line with the above summary, the following description of a number of specific and alternative embodiments are provided to understand the inventive features of the present invention. It shall be apparent to one skilled in the art, however that this invention may be practiced without such specific details. Some of the details may not be described at length so as not to obscure the invention. For ease of reference, common reference numerals will be used throughout the figures when referring to the same or similar features common to the figures.

FIG. 1 illustrates a block diagram of a process flow of a production line of bitumen packaging in accordance with one embodiment of the present invention. The process comprises air-cooling bitumen at step 101; pack filling bitumen to box at step 102; pack sealing each box at step 103; palletizing at step 104; and containerization at step 105. The bitumen, before it is being packed, is transported to a packing plant by tanker trucks from supply depot and stored temporarily in, typically a 18 to 24 metric ton skid tank. During the transportation and storage, the bitumen is maintained heated continuously to avoid hardening. Generally, the bitumen is maintained at around 110-120 degree Celsius, occurring in highly viscous form. Often, once the bitumen is hardened, it requires more heat energy to soften the bitumen again than to maintain heating. At the step 101, the bitumen is then pumped into a cooling apparatus for cooling it down to, say, around 70 or 80 degree Celsius. This temperature range is herewith adapted because the viscosity of bitumen would provide a reasonable smooth pumping from one location to another, and yet, able to be handled by any reasonable workers. It is understood that any such workers will not be in direct contact with the cooled bitumen (around 70-80 decree Celsius) when handling the bitumen, as the bitumen is packed in the corrugated box. The corrugated box provides some extend of thermal insulation. The bitumen is being cooled via a forced airflow cooling apparatus.

Referring back to the step 101 , the cooling apparatus comprises three cooling towers 200 as shown in FIG. 2A. Each of the cooling towers 200 comprises a supply pipe 202, a platform 204, fans 206 and a collection bin 208. The supply pipe 202 supplies the bitumen through a pump (not shown) and dispenses it on the platform 204. When the bitumen flows over the platform 204, and when reaches the edge, it forms a free falling cascade 205 of bitumen curtain. The fan 206 is mounted in front and possibly another at the back of the free falling cascade 205 to fan cool (forced-air cool) the bitumen. The bitumen is collected at the collection bin 208 beneath the platform 204.

The first round cooled bitumen is collected and pumped into another cooling tower via an outlet pipe for cooling in a same way, i.e. force air- cooling. Subsequently, the bitumen is further pumped into the third cooling tower for cooling. The bitumen is cooled to a desired temperature. The level of cooling bitumen depends on the actual setup of the cooling tower 200, the power of the fan, the ambient temperature, number of cooling tower 200 and other known reasons. As mentioned, it is desired that the bitumen is cooled from about 110-120 degree Celsius to about 70-80 degree Celsius or lower for packaging in the corrugate boxes.

FIG. 2B illustrates a platform 220 of the cooling tower 200 in accordance with another embodiment of the present invention. The platform 220 comprises a weir 222 forming a reservoir 221 on the platform 220 with an outwardly inclined surface 224. The bitumen is dispensed directly into the reservoir 221. The bitumen flows over the top of the weir 222 runs along the inclined surface 224. When the bitumen flows over the end edge of the inclined surface 224, the bitumen is regulated to form a cascade of bitumen curtain. With the weir 222 and/or the inclined surface 224, the bitumen flow is evenly spread across.

FIG. 2C illustrates a cross sectional view of the cooling tower 200 in accordance with an alternative embodiment of the present invention. The cooling tower 200 further comprises one or more dampers 255 situated beneath the platform 204. The damper 255 is a flat panel downwardly inclined towards the bottom space of the platform 204 in a manner that the bottom edge of the platform 204 is projected over the top middle surface of the damper 255. Operationally, the bitumen dispensed from the supply pipe flows over the platform 204 and forms a cascade of bitumen curtain and drops on the surface of the damper 255. The bitumen flows over the damper surface and when reaches the edge of the damper 255, it forms another cascade of bitumen curtain. Fans 206 are provided in various locations to fan cool the bitumen curtains.

It is understood that a good ventilation within each cooling tower would increase the cooling efficiency. Such ventilation can be realized by providing air vents or any air handling units. Air suction fans or the like would be useful to remove internal hot air.

When more dampers are desired, each subsequent damper is arranged in an opposing manner with the damper (or platform) immediately above it projected over its inclined surface.

The steps 102 to 105 are carried out in a conveying system. FIG. 3 illustrates a schematic diagram of the conveying system carrying out the step 102 and 103 in accordance with one embodiment of the present invention. At the step 102, the cooled bitumen from the step 101 are then pumped into a filling machine 302, and through the filling the machine 302, the bitumen is filled into individual boxes 301. Typically, the boxes 301 are adapted to hold around 25kg of bitumen per box. Each box can be a corrugated box provided with a polymer bag to contain the bitumen. The polymer bag can be a heat shrink UV resistant polymer material. In one embodiment, the filling machine 302 is also equipped with a static weight device to control the filing amount for each box, preferably, with +/- 0.5% tolerance. Each box 301 is then conveyed to a sealing machine 304 to seal the polymer bag.

In one embodiment, the polymer bag is fabricated into a generally rectangular-shaped bag with an opening for fitting with the corrugated box. The polymer can be a clear polymer bag that made up of about 15wt% to 25wt% of ethylene vinyl acetate (EVA) and about 75wt% to 85wt% low density polyethylene (LDPE). The polymer bag can have a thickness of about 0.4mm. The aforesaid specification is suitable for packing a great range of bitumen of different specifications.

Depending on the dimensions, the boxes are made for easy stacking and palletizing. It is desired that the boxes can be warehoused for up to 8 boxes high stack or so, and racks can be built for more storage space. In a further embodiment, the corrugated box is sized into 300mm (W) x 420mm (L) x 200mm (H).

The aforementioned method and system cool the bitumen through creating a vertical free-fall liquid curtain of bitumen. The curtain of bitumen provides a relatively large surface area of which, it can be effectively cooled through circulating ambient air by forced-airflow. The forced-airflow can be generated by an appropriate fan. It is possible that the fan can further be provided at both side of the bitumen curtain to improve the cooling efficiency. The above further suggests that it is possible to provide damper along the free-fall bitumen to further improve the cooling efficiency. Further, the bitumen can be uniformly cooled without any difficulty causes by viscosity variances in a jacketed pipe or a batch cooling apparatus. The continuous forced-air flow enables a consistent output of cooled bitumen for packing into the boxes.

In another embodiment, the cooling tower may supply chilled air to improved the cooling performance, if required.

The cooling and packing of bitumen is in the method by which the bitumen is cooled in a continuous free fall and packed in a special formulate polymer bag that made up of a combination of polymer and elastomer. The polymer bag containing the cooled bitumen is packed into a corrugate box, which is suitable for palletizing and storing. The bag of bitumen is usable straight out from the box. The entire bag of bitumen can be heated to melt to a usable form together without separating the polymer bag from the bitumen. Accordingly, it is hassle free unpacking and there is no wastage. Packing bitumen in such form is preferred because the polymer bag is only about 0.2- 0.3 wt% of the entire bitumen bag when compare with other form of bitumen packaging, such as bale-packed bitumen that consists up to 0.8 wt% or more of the polymer bag due to the multiple layers bale. In addition, the combination of EVA and LDPE enables our packing to have insignificant effect to the overall specification of the bitumen and keeping to the required specification range of bitumen. The process and system is also designed to meet commercial requirements of packing capacity and maintaining the integrity of the required bitumen specifications.

The cooling tower can be made out of mild steel, stainless steel, galvanized iron and/or the combinations thereof. The present system and method provides a cost effective and environmentally friendly form of packing, transporting and distributing bitumen. It is a relatively safer and cleaner way to handle bitumen by making is a small size and clean package of cooled bitumen.

Overall the invention reduces significantly the cost and use of fuel and energy in the whole supply chain mix. The invention eliminates the need to constantly keep bitumen in heated storage and transport from point of manufacturing to point of usage. Therefore reducing overall fuel consumption and reducing carbon emission.

The potential use of this invention is primarily in the area of bitumen storage and supply. However other liquid materials that have a need for cooling and packaging can also utilize this method and process.

FIG. 4 illustrates a cooling apparatus 400 adapted to cool down bitumen in accordance with a further embodiment of the present invention. The cooling apparatus 400 comprises a housing 401 , an inlet 402, an outlet 404, a plurality of fans 406, and an exhaust fan 408, and a ramp 410. The housing 401 is generally a rectangular housing with the inlet 402 extended into an upper side of the housing 401 at one end, and the outlet 404 extended into an lower side of the housing 401 at an opposing end. The ramp 410 is mounted across the length of the housing 401 with the higher end mounted beneath the inlet 402 and the lower end mounted beneath the outlet 404. The ramp may further comprises a ditch 412 and one or more steps 414. The ditch 412 is defined at the higher end along the width of the ramp 410. Towards the lower end of the ramp, the ditch 412 forms a weir that allows the ditch 412 to hold liquid. The one or more steps 414 are formed along the length of the ramp 410. The plurality of fans 406 are mounted above the ramp 410, and operable to force air to flow towards the ramp 410. The exhaust fan 408 is mounted above the outlet 404 to exhaust air from the housing 400.

Operationally, the fans 406 are in operation to force air flow towards the ramp. Hot bitumen is pumped into the cooling apparatus 400 through the inlet 402. The bitumen drops on the ramp 410 and subsequently flows into the ditch 412. The bitumen then overflows from the ditch 412 onto the incline surface of the ramp 410. The bitumen flows through the steps 414 and reaches the bottom of the ramp 410. During the flow, the bitumen is spread across the ramp 410 with a relatively large surface area. Due to the large surface area, the bitumen is effectively and evenly cooled by the forced airflow. The cooled bitumen is drawn out from the cooling apparatus 400 through the outlet 404.

In another embodiment, heating elements can be employed beneath the ramp 410 to slightly heat up the ramp 410 to prevent bitumen solidifying on the ramp 410.

The present invention suggests using forced airflow to cool down the bitumen. The present invention further suggests methods of increasing surface area of the bitumen flow to improve the airflow cooling efficiency. FIG. 5 illustrates another alternative embodiment of the present invention adapted to increase the surface area of the bitumen flow. The embodiment includes an inlet 500 having a outwardly flatten and tapered spout 510. Such outwardly flatten and tapered spout 510 allows the bitumen to flow out therefrom with a relatively large surface area.

It is an object of the present invention to provide a cooling tower having an upper region and a lower region. The bitumen is dispensed at the upper region and allowing the bitumen to flow downwardly to the lower region. The downward flow of the bitumen can be a free fall, or run across a flat platform provided across the upper region and lower region. In either case, there may be provided with a damping means for slowing down the bitumen flow. As the bitumen is flowing, there is provided a means for generating a cascade of bitumen curtain to increase the exposed surface area of the bitumen flow. As the surface area increases, the bitumen can be fan-cool (forced air) more effectively. As suggested above, the means for forming the bitumen can be a separate channel, or directly adapted on the bitumen supply pipe.

While it is preferred that the above suggested embodiments are aimed to provide structure and method for forming a cascade of bitumen curtain, thereby forming a large surface area of the bitumen flow, depending on the viscosity and the conditions of the relevant parts that the bitumen flow through, it is understood that the bitumen flow may not necessary form a whole (undamaged/undivided) cascade of bitumen curtain, or bitumen flow for cooling. But it should not affect the fundamental nature of the present invention.

While specific embodiments have been described and illustrated, it is understood that many changes, modifications, variations and combinations thereof could be made to the present invention without departing from the scope of the invention.

Claims

1. A polymer bag of a bitumen packaging, the polymer bag comprising: 15-25wt% of ethylene vinyl acetate (EVA); and

75-85wt% of low density polyethylene (LDPE), whereby the polymer bag is dissolved into the bitumen when the polymer bag is heated up together with the bitumen to a melting temperature.

2. The polymer bag according to claim 1 , wherein the polymer bag comprising 15wt% of the EVA.

3. The polymer bag according to claim 1 , wherein the polymer bag comprising 85wt% of the LDPE.

4. The polymer bag according to claim 1 , wherein the polymer bag is sized to amount about 0.2 to 0.3 wt% of the bitumen packaging.

5. The polymer bag according to claim 1 , wherein the polymer bag is about 0.4mm thick.

6. The polymer bag according to claim 1 , wherein the bag is fabricated into a generally rectangular-shaped bag.