This document relates to the field of transporting sulfur.
Generally, in Alberta, Canada, sulfur is produced in excess of market demand as a by product of oil and gas processing. Due to the normal low price of the commodity, the produced sulfur is stockpiled in (huge) outdoor blocks. These outdoor blocks are often stored in remote locations at or near processing facilities. When the fluctuating price of sulfur reaches a high point, the sulfur blocks are remelted and shipped by conventional methods.
Sulfur has traditionally been transported in its elemental form as a liquid, or as a prilled or small briquette solid. These modes of transportation have evolved in general from earlier transport in the form of crushed solid. Crushed solid transport has been legislated as unacceptable because sulfur dust is flammable/explosive and a pollutant.
As a liquid, sulfur is a dangerous good as defined in government legislation concerning transportable substances. Despite this, the liquid form has been the preferred mode of rail or truck transportation for continental deliveries.
Sulfur transported as a prilled solid is primarily destined for ocean transport. In the 1960s or so, when this form of sulfur was devised for transportation, bulk shipments of commodities were the common mode of international transport of goods.
Producing prilled sulfur requires a separate license for a prilling facility in Alberta. These facilities can expose high surface areas of hot sulfur to the atmosphere and therefore must be constructed to minimize pollution. Further, the processes used are complicated and expensive.
Sulfur prills are, for the most part, transported in open rail cars and in ocean going vessels. Exposure to weather and moisture, along with the high surface area, tends to produce sulfur type acids that corrode transport equipment. Moisture adsorbed onto and absorbed into the product can add to subsequent processing costs when the moisture must later be removed.
Producing small briquettes is expensive and requires complex infrastructure. In addition, these briquettes cannot be easily transported, as they have a large surface area for contact dust creation, and they must be kept in bags or contained in small packets.
According, it is clear there is a need for a simple, inexpensive mode of production of transportable sulfur over conventionally known methods. Patterns of commerce have been changing, and more and more trade is now done in the form of finished goods. Containerization as a mode of transport has evolved. Efficient global infrastructure for transporting containerized goods is now available. An interesting situation that is currently occurring is that there is a net flow of containers into North America that is not counterbalanced by flow of containers out of North America.
A method of transporting sulfur is disclosed, comprising: transporting a structurally reinforced sulfur block from a first location to a second location by machine. A structurally reinforced sulfur block for machine transport is also disclosed. A method of forming structurally reinforced sulfur blocks for machine transport is also disclosed.
A process is also described for producing structurally reinforced blocks of sulfur which then can be moved with conventional equipment from production to consumption points.
A structurally reinforced sulfur block is also disclosed, the structurally reinforced sulfur block being liftable by freight lifting equipment, and dimensioned to fit within a single transport container.
A transport container loaded with at least one of the disclosed sulfur blocks is also disclosed. A method comprising removing at least one structurally reinforced sulfur block from the transport container is also disclosed. A method comprising adding at least one structurally reinforced sulfur block to the transport container to produce the transport container is disclosed.
These and other aspects of the device and method are set out in the claims, which are incorporated here by reference.
The concept of forming sulfur into structurally reinforced blocks larger than prills or briquettes for transporting the element is novel. This is understandable given the uncommonality of containerization as a mode of transport at the time prilling was developed, and the acceptance of flowable bulk transport or tanked liquid transport as norms of the day.
Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which:
Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.
The process disclosed herein calls for the use of smaller structurally reinforced transportable blocks of sulfur (as opposed to the large industrial storage blocks found at well sites, for example) that can be lifted with conventional lifting equipment, such as for example forklifts, telehandlers, freight-lifting cranes, or similar equipment for placement into standard or non-standard containers for transport.
Referring to
Liftable by freight lifting equipment refers to the fact that the structurally reinforced sulfur block may be able to be lifted by conventional freight lifting equipment—in other words, the block may be not too large to be transported by freight handling equipment in a conventional fashion. Because of the standardization of transport containers in the intermodal freight industry, the structurally reinforced sulfur block may be dimensioned to fit within a single transport container. However, it is understood that structurally reinforced sulfur blocks contained within the scope of this document need not be transported only by container, as is illustrated in
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
The methods disclosed herein may comprise forming any of the structurally reinforced sulfur blocks 10 disclosed herein. It should be understood that there are various ways of forming the solid blocks 10 disclosed herein, such as by molding, compression, or by carving and buffing out smaller blocks from a larger block.
Referring to
In order to facilitate removal of the block 10 from the mold 34, various mechanisms may be employed. For example, at least one hook mechanism may be embedded within the top of block 10, and the block 10 can then be lifted from the mold 34 via the hook mechanism. In another embodiment, vacuum suction may be employed to draw the block 10 out of the mold 34.
In other embodiments, sulfur 36 may be melted after placement in the mold. In further embodiments, the sulfur 36 may be melted in a continuous flow through oven (not shown), which may use infrared heating technology for example. In such embodiments, the sulfur 36 may be placed in the mold 34 in an at least partially crushed form, and then heat may be applied to melt the sulfur. In this way, partially crushed sulfur may be fed into a series of molds 34 on a conveyor-type-apparatus (not shown), which may in turn carry the molds 34 into the continuous flow through oven to melt the sulfur and form the block 10.
In some embodiments, the methods disclosed herein may involve assisted cooling stages, using cooling techniques, such as placing mold 34 with sulfur 36 into a vat of room temperature water for example, or by providing internal coolant circulation within the walls of mold 34.
Referring to
Any of the methods disclosed herein may further incorporate molds 34 coated to allow easy removal of the structurally reinforced sulfur block 10. Mold coatings or choice of mold lining material may assist the removal process. For example, mold 34 may be coated with reduced friction materials, such as Teflon, in order to aid the removal of block 10 from mold 34 (shown in
Sulfur can also be prepared in a stagewise fashion to enhance the mechanical properties for the purpose of shipping. An example of this is where the structurally reinforced sulfur block 10 is structurally reinforced by layering, for example layering during molding. Referring to
Referring to
In some embodiments, the structurally reinforced sulfur block 10 is structurally reinforced by annealing. Referring to
In some embodiments, the desired average density of the sulfur in the structurally reinforced sulfur block is greater than the average density achieved by basic molding alone. The average density of the sulfur in the structurally reinforced sulfur block is calculated using the entire volume of sulfur in the block, including the volume of void spaces, if any, but not including the volume taken up, or introduced, by reinforcing material, if present. In some embodiments, the desired average density is at least 1.85 g/cm3, for example between 1.88 and 2.10 g/cm3. Sulfur blocks formed by layering during molding according to the disclosure of this document were measured to have a density of 1.89 g/cm3, whereas sulfur blocks formed by basic molding were measured to have a density of 1.78 g/cm3.
A method of forming a structurally reinforced sulfur block 10 may incorporate applying a protective covering 26 (shown in
In other embodiments, the sulfur may be formed into a structurally reinforced sulfur block 10 using compressive force (not shown). This may be carried out by placing pulverized or at least partially powderized sulfur into a compression mold, and applying compressive force for example. In some embodiments, the sulfur block 10 may be formed by addition of a plasticizer in order to add toughness to the solidified sulfur.
An exemplary structurally reinforced block of sulfur is about 64 ft3, weighs about 8,000 pounds, and is dimensioned so that it can be lifted by a variety of makes of telehandlers. A multiple of about 6 such blocks is under the carry weight limitations of most standard trucks or containers. In order to insert, for example, 6 such blocks without stacking into a normal 20 foot container, suitable dimensioning would be about 4 foot high by 5 foot wide by 3 foot deep.
Of great importance in the commercial worthiness of the “mini block” approach to transporting sulfur, is the robustness of the blocks in resisting handling stresses and strains. Elemental sulfur by itself has comparatively low mechanical strength versus normal materials of construction of “block forms” such as concrete, plastic or wood. Given that the modulus of rupture of sulfur is reported in the literature is approximately 200 psi, a rectangular block of sulfur having the dimensions of 3′×4′×5′ is estimated to be capable of withstanding an applied force of ˜184,000 lbs in a standard flexural strength test. Such a block only weighs about 8000 lbs, about 4.4% of the required force to break the block. This suggests that elemental sulfur in the “mini block” form disclosed herein has sufficient mechanical strength to withstand the rigors of handling and transportation via containers. Rounding the mold corners of the block (such as illustrated in
The structurally reinforced sulfur blocks 10 disclosed herein may be formed from an industrial storage block (not shown) of sulfur. The structurally reinforced sulfur block 10 may also be formed from sulfur byproducts from a well.
Referring to
It should be understood that a block includes shapes beyond mere rectangular cube or polyhedrons, for example pyramids, spheres, or any type of solid mass that may be easily handled, transported, and fit in a transport container. However, the provision of dimensions which reduce the chance of chippings or crushed edges/corners is advantageous, in order to avoid the unnecessary creation of hazardous sulfur dust. Further, it may be advantageous to polish or finish the edges and/or sides of a block 10 in order to add further safety.
Exemplary freight handling equipment include, but are not limited to hand pallet trucks, walkie low lift truck, towing tractors, walkie stackers, rider stackers, reach trucks, electric counterbalanced truck, IC counterbalanced truck, sideloaders, telescopic handlers, slip sheet machines, walkie order picking trucks, rider order picking trucks, articulated very narrow aisle counterbalanced trucks, guided very narrow aisle trucks, sod loaders, and freight cranes.
It should be understood that various features of the methods and blocks disclosed herein may be combined with various other features. Blocks made according to the disclosure herein may be made for as little as US $7/metric tonne. This is contrasted with current prilling techniques, which cost US $14-30/metric tonne.
Reference to basic molding in this document refers to filling a mold with liquid sulfur and allowing the sulfur to cool and solidify at room temperature. As discussed above, basic molding produces a sulfur block that has a rigid crust and a crumbly interior, which may include internal void spaces. This roughly 1 inch crust, when grasped, is rigid and gives the block most of its physical strength. In blocks of this type that are large enough to require handling with machines, the strength afforded by the crust is insufficient for the rigors of machine transport. In some embodiments, a structurally reinforced sulfur block may be formed by solidifying liquid sulfur in a mold using sufficiently low external temperatures, such as those experienced outdoors during Canadian winters, in order to form a sulfur block with a crust that is sufficiently thick to afford a molded block sufficient strength and toughness for machine transport.
In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/CA2009/001168 | 8/27/2009 | WO | 00 | 7/2/2010 |
Number | Date | Country | |
---|---|---|---|
61092390 | Aug 2008 | US |