Method and composition for the preparation or cold blending of a bitumen composition for subsequent transport to a selected work cite

Description

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention relates to the preparation of a bituminous composition, such as asphalt, which is prepared, cooled and packaged for subsequent transport and use at a work cite, such as a road or highway. The invention relates to the preparation of a bituminous composition, such as asphalt, modified asphalt, or engineering asphalts, which is prepared, cooled and packaged for subsequent transport and blending or reaction and use at a work cite, such as a road or highway, roofing manufacturing unit, cable manufacturing unit and other types of manufacturing and processing units.

(2) Brief Description of the Prior Art

As used herein, bitumen, bitumen composition and asphalt are synonymous. Bitumen is completely soluble in carbon disulfide, and composed primarily of a mixture of highly condensed polycyclic aromatic hydrocarbons. Asphalt is most commonly modeled as a colloid, with asphaltenes as the dispersed phase and maltenesmateria as the continuous phase (though there is some disagreement amongst chemists regarding its structure). Although a considerable amount of work has been done on the two to discover the chemical composition of asphalt, it is exceedingly difficult to separate individual hydrocarbon in pure form and it is almost impossible to separate and identify all the different molecules of asphalt, because the number of molecules with different chemical structure is extremely large

Most natural bitumens contain sulfur and several heavy metals, such as nickel, vanadium, lead, chromium, mercury, arsenic, selenium, and other toxic elements Bitumens can provide good preservation of plants and animal fossils.

Asphalt/bitumen can sometimes be confused with “tar”, which is a similar black, thermoplastic material produced by the destructive distillation of coal. During the early and mid-20th century when town gas was produced, tar was a readily available product and extensively used as the binder for road aggregates. The addition of tar to macadam roads led to the word tarmac, which is now used in common parlance to refer to road-making materials. However, since the 1970s, when natural gas succeeded town gas, asphalt/bitumen has completely overtaken the use of tar in these applications. Other examples of this confusion include the La Brea Tar Pits and the Canadian tar sands. Pitch is another term mistakenly used at times to refer to asphalt/bitumen, as in Pitch Lake.

Natural deposits of asphalt/bitumen include lakes such as the Pitch Lake in Trinidad and Tobago and Lake Bermudez in Venezuela, Gilsonite, the Dead Sea, asphalt/bitumen-impregnated sandstones known as bituminous rock and the similar “tar sands”. Asphalt/bitumen was mined at Ritchie Mines in Macfarlan in Ritchie County, West Virginia in the United States from 1852 to 1873. Bituminous rock was mined at many locations in the United States for use as a paving material, primarily during the late 1800s.

Asphalt/bitumen can be separated from the other components in crude oil (such as naphtha, gasoline and diesel) by the process of fractional distillation, usually under vacuum conditions. A better separation can be achieved by further processing of the heavier fractions of the crude oil in a de-asphalting unit, which uses either propane or butane in a supercritical phase to dissolve the lighter molecules which are then separated. Further processing is possible by “blowing” the product: namely reacting it with oxygen. This makes the product harder and more viscous.

Asphalt/bitumen is typically stored and transported at temperatures around 150° C. (300° F.). Sometimes diesel oil or kerosene are mixed in before shipping to retain liquidity; upon delivery, these lighter materials are separated out of the mixture. This mixture is often called “bitumen feedstock”, or BFS, or bitumen or asphalt compositions. Some dump trucks route the hot engine exhaust through pipes in the dump body to keep the material warm. The backs of tippers carrying asphalt/bitumen, as well as some handling equipment, are also commonly sprayed with an agent before filling to aid release. Diesel oil is no longer used as a release agent due to environmental concerns.

Heretofore, the manufacture of bitumen compositions has required heating of the additives and the maintaining of the produced composition at elevated temperatures even as the resultant composition is being transported to a job cite, such as an area near the building of a road or highway, or airport runway, or roofing products manufacturing unit, or bituminous products process plants or the like. This becomes extremely problematic where the work cite is in a location far away from the manufacturing facility, requiring considerable time for transporting the bitumen composition by truck, barge or ship. The bitumen composition must be heated continuously during the transport step and storage. Where the job cite is overseas, the problem is compounded, oftentimes requiring the building and operation of a substantial manufacturing facility far from readily available sources of bitumen or additives for the formation of the ultimately desired composition.

Asphalt or bitumen is a thermoplastic material, a consistency of peanut butter or harder at ambient temperatures. It is a brittle solid at cold temperatures and liquid at high temperatures. It is easier and more cost effective to process most asphalts/bitumens in the liquid form.

The present invention addresses problems associated with the manufacture, storage and delivery of bituminous compositions such that the necessity for continued heating during transportation and delivery to the work cite is eliminated.

The present invention provides for the preparation of a carefully defined cold blend/mixture of bitumen compositions that, when subsequently heated and mixed and/or blended at a hot mix plant yield a composition that meets the project, job and/or agency binder specifications. Some of the benefits of such a process are:

• • (1) elimination of qualifying, ordering and logistically processing multiple materials;
  • (2) elimination of metering, blending and/or mixing ingredients in proper ratios;
  • (3) minimization of the storage areas, or tankage necessary to support multiple ingredients;
  • (4) minimization of operational and staff personnel, as well as the need for the presence at the job cite of an advanced knowledgeable technical staff;
  • (5) the elimination of unused, excess raw material inventories at the completion of the project;
  • (6) the elimination of an expensive process system (capital and operating costs) to produce polymer modified bitumen (PMB);
  • (7) the ability/flexibility to make large or small quantities of PMB's as demand dictates;
  • (8) the minimization of wastes, packaging containers of ingredients, off-spec products, etc.;
  • (9) increasing the distance the product may travel; making competition and market reach more economic and viable;
  • (10) reducing the risks of gelling and loss of quality at time of re-use and after re-heating; and
  • (11) eliminating technical risks of loss of quality and reduction of properties of materials used in the production of the PMB's.

In accordance with the present invention, the majority of the work and complex formula development is done using the teachings herein, and the end user simply heats blends/mixes and uses the resultant product to make hot mix pavement, or in other uses.

In the present invention, bulk cold packed containerized pre-blended modified asphalt/bitumen is prepared for subsequent use in asphalt, cold patches and/or but not limited to roofing products. Bulk cold packed containers in the form and various sizes of polyolefin bags, big bags, jumbo bags, polybags, bitumen transportation containers (commonly referred to as Bitutainers or ISO Containers) or steel drums, as commonly used in the industry, provides a means to transport and use modified bitumen, PMB's, into areas not equipped for common bulk transportation by truck, rail or ship or simply as a preferred form by the user.

The cold packaged containerized bitumen is formulated to contain non-reacted or prepared mixtures of bitumen, additives, polymers, modifiers, extenders, and associated ingredients that at the use site are melted and blended or added to host bitumen and blended in proportions yielding bitumen meeting project specifications or requirements. The bulk cold packed containerized pre-blended bitumen is prepared using a process involving and combining a specially designed steel belt process conveyor system which combines selected ingredients into a non-reacted mixture which in turn is feed into an extruder forming the mixture into morphology suitable for filling the type of bulk container used.

The containers, ‘Bitutainers’ are available in various sizes from 50 gals to 5,000+ gals and capabilities. Larger ISO type containers with capacities up to 30 MT are reusable and equipped for various types heating and pouring/pumping capabilities. Smaller drums, in the 150-250 Kg capacity range typically non-usable, require a heating and pouring system such as a decanter. Polybags in the 25-2,000 Kg capacity are constructed from materials which permit the entire bag to be added to hot bitumen, the entire package with contents are used, there is no waste.

The pre-blended modified asphalt may be specifically formulated to meet specifications or project requirements and be suitable for direct use through heating and mixing or may be in a concentrate form for addition and letdown in a host hot bitumen for mixing.

Markman Constructions

I intend for the following words and phrases to have the following meanings, as used in the claims and all other parts of the specification:

• • (1) Bitumen composition: As described in the section entitled “Brief Description Of The Prior Art”.
  • (2) Cold blending: a step in which the additives are mixed, blended and/or reacted without application of an external heat source. This may involve liquids at ambient temperatures and/or particulate solid materials, such a powdered or pelletized polymers such as SBS, PE, terpolymers, ground tire rubber. Related additives, such as cross-linking agents such a powdered or pelletized sulfur of value added C-L agents which may contain multiple ingredients again in powder or pellet form may also be used. It also includes use of additives such as hard asphalts (PDA's, asphaltenes, solvent precipitated asphaltenes, TLA, Gilsonite, or carbon black)
  • (3) Receptacle: a body, such as a housing, a tank, or a reactor.
  • (4) Additive(s): Any chemicals known to those skilled in the art of formulating or manufacturing final asphalt compositions for ultimate use in roads, highways, roofs, and the like. Additives may include: natural and synthetic polymers; ground tire rubber; lubricants; Naphtanic oils; cross-linking agents, such as sulfur; emulsifiers; thinners (to be distinguished from modifiers, which are the essentially polymeric chemicals).
  • (5) Mixing: to combine into one mass.
  • (6) Heating: a step in which the additives are mixed, blended and/or reacted with application of an external heat source.
  • (7) Exposing: a step in which the additives or the composition are directly or indirectly caused to be contacted by a known thermal reduction variant within a receptacle.
  • (8) Means for reducing the temperature: a device(s) for causing the temperature of additives during mixing or the composition to be lowered to a pre-determined temperature before the step of packaging.
  • (9) Pre-determined temperature: the temperature at which the additives or the composition are caused to be lowered by the temperature reducing means
  • (10) Packaging: the step of introducing the additives or the composition into a container for subsequent transport to a work cite.
  • (11) Cooled bitumen composition: the resulting product of the step of exposing.
  • (12) Container: any device for the transport of a given amount of a plurality of additives or a composition, re-usable or non-reusable.
  • (13) Heat exchanger: a device used to transfer heat from a fluid on one side of a barrier to a fluid on the other side without bringing the fluids into direct contact with one another.
  • (14) Pre-cooled temperature reducing fluid: air or other gas, or a liquid.
  • (15) Elongated continuously rotatable belt: a device driven by an energy source and having first and second opposing surfaces, upon one surface is deposited one or more additives and/or bituminous composition(s).
  • (16) Incrementally deposited: the deposition of additives or the composition onto a surface for the purpose of reducing the temperature of the additives or the composition to a pre-determined temperature.
  • (17) Second receptacle: a housing or full or partial enclosure for a continuously rotatable belt.
  • (18) Means for introducing said composition into said second receptacle and onto said belt: a device for transporting the additives or the composition between a receptacle where additives are mixed or reacted to form a composition, and thence to an area for exposure of the additives or the composition to means for reducing the temperature.
  • (19) Cutting means: a device for separating a composition or additives into portions of a given dimension.
  • (20) Extruding means: a device for producing various geometric profiles of additives or composition that may thereafter be separated into given lengths and/or configuration.
  • (21) Composition: the combination of additives using the method of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical flow illustration of a device incorporating the present invention wherein additives are reacted or blended in a receptacle prior to being cooled and packaged.

FIG. 2 is a view similar to FIG. 1 illustrating the flow of the resultant composition subsequent to the procedures shown in FIG. 1.

FIG. 3 is an illustration of an extruder system incorporated into the invention.

FIG. 4 is a graphical illustration combining to procedures or steps illustrated in FIGS. 1 through 3, but showing an alternative step of providing extrusion of the composition subsequent to the cooling procedure.

FIG. 5 is a graphical flow diagram of a process using the invention.

SUMMARY OF THE INVENTION

A cold blending and containerizing method and apparatus are disclosed and claimed for preparing a bitumen composition for subsequent transport to a selected work cite and final preparation. Into a first receptacle is introduced a pre-selected quantity of one or more additives for the formation of the composition. The additives are then mixed and/or heated within the receptacle to form the bitumen composition. The bitumen composition is exposed to means for reducing the temperature of the composition to cool the composition to a pre-determined temperature, such as by use of one or more fluids, preferably delivered onto at least one side of a rotating belt, and thereafter packaging the cooled bitumen composition into at least one container for transport to a selected work cite.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Description of a Theoretical Apparatus and Method

As an illustration of an asphalt composition preparation, cooling and packaging which would use the present apparatus and method, the following composition formulas may be prepared using the additives as described below:

• • 1. A. Asphalt layer deposited on belt (described above) in predefined layer (quantity), 250-300° F., approximately 85-98% by volume of final composition.
    • B. Cross-linking agent is sulfur, deposited on top of molten asphalt, ambient powder, 60-80° F., approximately 0.05-2.0% by volume of final composition.
    • C. SBS powder deposited uniformly on top of molten asphalt, ambient powder, 60-80° F., approximately 0.5-20% by volume of total composition. Cooling starts immediately when the hot liquid additives contact the cooler belt. As the cooling continues, the particulate additives become embedded in the asphalt deposited on the belt during the cooling step.
    • D. Resultant composition from belt feed is placed into extruder to further cool the composition to between about 30-60° F., and 100% of the resultant asphalt composition is fed into an extruder (described above).
    • E. Extruded, cooled asphalt composition is cut to desired form and fed into container/packages, at a temperature of about 50-70° F.
  • 2. A. Base asphalt and extender oil additives are heated and mixed in a receptacle.
    • B. Additive “A” is fed to a belt and deposited in a uniform predefined layer (quantity).
    • C. A sulfur cross-linking agent, is deposited on the belt top of the heated asphalt.
    • D. SBS powder is deposited uniformly on the belt on top of the asphalt to complete the preparation of the asphalt composition.
    • E. The asphalt/bitumen composition on the belt is fed into an extruder.
    • F. The composition is cut to desired form and fed into container/packages.
  • 3. A. Base asphalt and extender oil additives are heated and pre-blended/mixed.
    • B. The additives are fed to a continuous, looped belt and deposited in a uniform predefined layer.
    • C. A sulfur cross-linking agent, is then deposited on top of the additives and on the belt.
    • D. Polymer 1: SBS powder is deposited uniformly on top of the additives.
    • E. Polymer 2: polyethylene pellets are deposited uniformly on top of the additives and the SBS powder additive to form the final bitumen/asphalt composition.
    • F. The composition on the belt is fed into the extruder.
    • G. The extruded composition is cut to desired form and feed into container/packages.
  • 4. A. A heated (250-300 F) asphalt/bitumen additive is deposited on a continuous looped belt to form a layer deposited on the belt, in a predefined layer (quantity), to provide approximately 85-98% by volume of the entire composition.
    • B. A sulfur cross-linking agent, in the form of an ambient powder (60-80 F) is deposited on top of the heated asphalt additives, to provide approximately 0.05-2.0% by weight of the entire composition.
    • C. SBS powder is deposited uniformly on top of the heated bitumen/asphalt SBS powder additives, at approximately 0.5-20% by weight of the entire bitumen/asphalt composition.
    • D. A thin layer of base asphalt/bitumen additive is deposited over the additives of “A”, “B” and “C” at a temperature of about 150-225 F to seal the additives and form the final asphalt/bitumen composition. The temperature of this step for the composition is reduced by exposing the surface of the composition to means for reducing the temperature, such as cool air or inert gas jets or water misters or foggers directed onto a surface of the belt while cold water, streams jets or similar liquid or gaseous material is sprayed onto another, i.e., the underside, of the belt not containing the additives. The temperatures required for appropriate cooling of the additives is determined by the minimum temperature required to flow into an extruder or similar device for packaging, per requirements.
    • E. The bitumen/asphalt composition is fed from the belt at between about 30-60 F into an extruder.
    • F. The extruded composition is cut to desired form and feed into container/packages, 50-70° F., 100% of cold mixed materials.

Now with reference to the Figs., there is shown in FIGS. 1 and 4 the apparatus for the mixing of the additives used to make a bitumen/asphalt composition. Raw materials 1, 2, and 3, such as those described in the theoretical example described herein, are separately introduced into a receptacle 4, which, as shown, is a three-sided vat or reactor. The receptacle 4 includes an electrically driven agitator, of known construction, for mixing and agitating the additives as they are blended or reacted in the receptacle 4. Although not shown, the receptacle 4 may also include a heat exchanger or other heating means for heating the additives during the mixing step. The lower portion of the receptacle 4 contains a flow line 4A leading to a pump 6 for circulating the additives back into the receptacle 4 as the mixing or reaction is continued. The heat exchanger may be placed within the receptacle 4 or, alternatively, exterior of the receptacle 4, such as within the flow line upstream or downstream of the pump 6. A valve 6A is placed in the flow line 4A for selective directing of the flow either back into the receptacle 4 or, when closed, to a connecting portion of flow line 4A which may contain auxiliary equipment for a number of procedures, such as strainers and/or filters 7.

FIG. 2 illustrates the continuous, loop belt system and cooling procedure used in the invention. The conduit line 4A transmits the additives which have been mixed in the receptacle 4 as in FIG. 1 to provide the bitumen composition, from the components shown in FIG. 1 to a second receptacle or housing 20. The receptacle 20 has a continuously moving elongated belt made of known construction, such as steel, aluminum or elastomer members, or the like, forming the belt 8. In lieu of depositing the bitumen composition onto the belt 8, additives for the formation of the bitumen composition may be introduced separately into the receptacle 20 and on to the belt 8 by use of one or more containers 9 and 10, placed just over the belt 8. The additives, pre-heated, are thus introduced onto the belt 8 incrementally or continuously as the belt 8 travels horizontally within the receptacle or housing 20. An exhaust system 11 is provided through the top of the receptacle 20 to vent fumes and the like as the bitumen composition is deposited and cooled along the belt 8. As the belt 8 continues to be moved along a horizontal path within the receptacle 20, a chilling system 13 below the belt 8 sprays or otherwise injects water or other cooling fluid either directly onto the lower face 8A of the belt 8 such that the fluid does not directly contact the bitumen composition on the belt 8, but provides cooling of the composition by indirectly cooling it through the belt 8. A troth 13 below the belt 8 collects the cooling fluid, if in liquid form, and transmits it through recirculation lines 21 into a cooler device, such as refrigeration device 22, thence back through recirculation conduit 21A and onto the lower face 8A of the belt 8.

FIG. 3 illustrates the steps and means used to extrude and package the cooled bitumen composition. A mechanical extruder 14 is placed in communication with one end of the rotating belt 8 such that after the composition is cooled to the pre-selected temperature, the composition may be delivered to the extruder and processed therein in a known manner. Thereafter, the extruded composition is transferred into drums 15, barrels 16 and/or bags 17, for subsequent delivery to a work cite.

Optionally, all additives may be pre-blended (as opposed to reacted) and deposited onto the belt as a homogenous mixture of bitumen. If polymers are used, they have not been dissolved nor have they been cross-linked.

Typically, the asphalt initially will be hot, such as 200-350° F. The polymers and related additives may be dry, particulate solids at ambient conditions. Any cross-linking agents may be powder sulfur, or oil extender or pelletized sulfur. The base asphalt may be a combination of asphalts and may include extender oils, and other additives such a PPA, polyphosphoric acid or other materials known to change the base asphalt properties and/or chemical composition.

It is assumed that at the work site, there are tanks or vessels to melt and mix the packaged blend of materials in a fashion suitable to yield the desired PMB. The melters, typically referred to as decanters, are packaged units sold for the purpose of melting and transferring the hot liquid bitumen to tanks for subsequent mixing, storage and delivery to the hot mix plant for combination with the aggregates.

FIG. 4 is an illustration of the method and apparatus combined as in FIGS. 1 through 3 as well as including an extruder 14 for extruding the composition subsequent to processing on the belt 8 and before packaging into containers 15, 16 and/or 17.

Now, with reference to FIG. 5, there is shown a general process flow diagram for the invention. Bitumen/asphalt and/or additives 50 through 55 are delivered into a first housing 56 or 57 for proportionate blending or reaction. Additives 55 include other performance enhancing additives, carbon black, hard asphalts (PDA's, Gilsonite, Asphaltenes, etc.) chemicals and sustainable materials beneficial to performance and specification compliance of the composition. The resultant composition is placed onto a chilled steel belt process system 58 for cooling. The composition is then extruded by extruder 59 and then delivered to one or more polybags 60, drums 61 and/or bitutainers 62 for transport to a work cite.

The belt assembly 8 and cooling system may be as described in PS-452 ENG 10.2004, “Sandvik bitumen-asphalt packaging” system, the total disclosure of which is hereby incorporated herein, and which device is available from Sandvik Mining, World Trade Center, Tower C, 15^th Floor, Strawinsky 1545, 107 XX Amsterdam, Netherlands. This system must be reconfigured in accordance with the present invention to accommodate the bitumen/asphalt and additives for the formation of the composition as disclosed herein.

Although the invention has been described herein, it should be understood that this is by illustration only, and that changes and modifications may be made to the apparatus and method which are well within the abilities of one having ordinary skill in the art but still remain within the scope, spirit and intent of the invention, and that scope of the invention is as defined in the claims, below.