Patent Application
20130029101
Embodiments of the present invention relate generally to asphalt compositions and asphalt binder modifiers useful therein as anti-stripping agents and/or for improving the tensile strength of such compositions. Particularly, the invention relates to the use of oil derived from the thermo catalytic conversion of biomass as asphalt binder modifiers for asphalt compositions.
In road construction, petroleum-derived asphalt and aggregate mixtures are applied to the road surface. These materials can be obtained by mixing anionic or cationic asphalt emulsions with aggregate, such as stone chips, gravel or sand, or by mixing free flowing heated asphalt with aggregate, by a hot mix or warm mix process. The quality of the road surface is generally dependent upon the strength of the bonds between the asphalt and aggregate. Rutting, or permanent deformation, is one of the main failure mechanisms for asphalt pavements. Excessive permanent deformation can occur in mixtures that lack adequate stiffness and/or strength at high temperatures. It is generally believed that tensile strength is a good indicator of mixture cohesion and can be related to the rutting potential of asphalt mixtures. Accordingly, it is desirable to develop asphalt binder modifiers that result in increased tensile strength and that reduce the potential for rutting.
Additionally, asphalt compositions can have relatively poor adhesion to aggregate in the presence of water. Generally, unless the aggregate is thoroughly dried, the aggregate surface remains wetted by water during blending with the asphalt, resulting in a weak boundary layer. Even if the surface of the aggregate is dry at the time it is blended with the asphalt, the eventual permeation of water from within an aggregate's micro- or meso-pores to the aggregate's surface, or the penetration of environmental water into the composition reaches the aggregate surface and interferes with the bond between the aggregate and the asphalt. This can result in stripping of the asphalt binder from the aggregate thereby weakening the adhesion between adjacent aggregate particles. In turn, under load of traffic this can lead to pavement failures including flaked pavement, “raveling”, cracking, and potholes.
To avoid such failures, adhesion-improving materials known as an anti-stripping agent (ASA) can be added to the asphalt. Before the mixing operation, ASAs are added to the petroleum-derived binder to reduce its surface tension and to induce on the binder an electrical charge opposite to that of the aggregate surface. Organic amines, have been traditionally used. They increase the hydrophobicity of the aggregate, making the aggregate resistant to the penetration of water so that water seeping towards the aggregate/asphalt interface does not tend to destroy the bond between the asphalt and the aggregate. Existing ASAs lack functional group diversity; e.g., liquid ASAs are generally derived from petroleum are alkyl or aryl amines or polyamines while solid ASAs are usually based on hydrated lime. Petroleum-derived amines used as ASA materials are primary alkyl amines such as lauryl amine and stearyl amine, and the alkylene diamines, such as the fatty alkyl substituted alkylene diamines. In addition to functional diversity, amine ASAs have concerns regarding heat stability at the high temperatures needed to adequately heat the binder. They can also be costly to synthesize.
Hydrated lime is a common anti-stripping agent and can be added by sprinkling it over the pre-wetted coarse aggregate or it may be added in the form of slurry. There are difficulties associated with both methods. There can be difficulty achieving adequate coating of the aggregate when adding hydrated lime in dry form. When added in a slurry form, there is an increase in cost associated with the fuel needed to heat the aggregate, and thus an increase in production cost. With both methods there are concerns related to health hazards due to inhalation and skin exposure. Accordingly, it is of interest to develop new anti-stripping agents that enhance the asphalt's adhesion to the aggregate in the presence of water and that avoid the issues associated with either amine ASAs or hydrated lime.
Recently, U.S. Patent Application 2010/0275817, entitled “Asphalt Materials Containing Bio-oil and Methods for Production Thereof,” has disclosed that bio-oil produced from the non-catalytic fast pyrolysis of a biomass can be used as an asphalt binder modifier. Non-catalytic fast pyrolysis produced bio-oils utilized by the 2010/0275817 application are characterized by being water soluble and having high oxygen content and high anhydro sugar content. Accordingly, because the composition of biomass derived oils vary greatly depending upon the processes used to derive the oil, bio-oil produced from non-catalytic fast pyrolysis is not indicative of whether other biomass derived oils may be used as an asphalt binder modifier.
Despite the environmental advantages of utilizing a renewable resource as the source for the asphalt binder modifier, it has been discovered that such non-catalytic fast pyrolysis bio-oils do not have a positive impact on tensile strength.
It would therefore be advantageous to have an asphalt binder modifier produced from a renewable source that results in improved tensile strength and enhanced adhesion of the asphalt to the aggregate in the presence of water. It would also be advantageous if such an asphalt binder modifier does not have a significant negative impact on the performance grade.
The objective of the current invention is to develop asphalt binder modifiers from a renewable source and, in particular from biomass.
It is a further objective of the current invention to develop improved anti-stripping agents from biomass-derived feeds that have a greater functional group diversity than the currently used anti-stripping agents.
It is yet another object of the current invention to develop improved asphalt binder modifiers from biomass derived feeds that result in improved tensile strength for the resulting asphalt concrete.
In particular, in one embodiment of the present invention, there is provided an asphalt binder modifier produced by the thermo-catalytic conversion of a biomass.
In a further embodiment, there is provided an asphalt binder modifier derived from a biomass T-C oil produced from the thermo-catalytic conversion of a biomass; wherein at least a portion of the biomass T-C oil is at least partially hydrotreated to thereby form the asphalt binder modifier; and wherein the asphalt binder modifier has an oxygen content lower than the oxygen content of the biomass T-C oil and has a boiling point of at least about 650° F.
In another embodiment of the present invention, there is provided an asphalt binder comprising asphalt and any of the asphalt binder modifiers described above.
In yet another embodiment, there is provided an asphalt concrete comprising an aggregate and such asphalt binder comprising asphalt and any of the above described asphalt binder modifiers.
Embodiments of the present invention are described in detail below with reference to the attached figures, wherein:
The following detailed description of the invention references various embodiments. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. The scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.
The present invention relates to the use of biomass T-C oil as an asphalt binder modifier to improve the tensile strength of asphalt concretes and/or as an anti-stripping agent for asphalt concretes or asphalt-containing roofing materials. As used herein, “biomass T-C oil” refers to oil from the thermo-catalytic conversion of biomass, as further described below.
Pyrolysis as used herein refers to non-catalytic pyrolysis processes. Fast pyrolysis processes are pyrolysis process for converting all or part of the biomass to bio-oil by heating the biomass in an oxygen-poor or oxygen-free atmosphere. The biomass is heated to pyrolysis temperature for a short time compared with conventional pyrolysis processes, i.e. less than 10 seconds. Pyrolysis temperatures can be in the range of from about 200° C. to about 1000° C. Often the biomass will be heated in a reactor using an inert heat carrier, such as sand. As used above, the term “oxygen-poor” refers to an atmosphere containing less oxygen than ambient air. In general, the amount of oxygen should be such as to avoid combustion of the biomass material, or vaporized and gaseous products emanating from the biomass material, at the pyrolysis temperature. Preferably the atmosphere is essentially oxygen-free, that is, contains less than about 1 weight percent oxygen.
Biomass thermo-catalytic conversion as used herein refers to a catalytic pyrolysis, wherein a catalyst is used to help facilitate conversion of the biomass under fast pyrolysis type conditions. Accordingly, in a biomass thermo-catalytic conversion process a catalyst is used in the reactor to facilitate the conversion of the biomass to oil (biomass T-C oil). The catalyst can be pre-mixed with the biomass before introduction into the reactor or be introduced into the reactor separately. If introduced separately into the reactor a particulate catalyst can be used in place of all or part of the inert heat carrier. The catalyst can be a heterogeneous acid catalyst.
It has been discovered that certain fractions of biomass T-C oil compositions produced by biomass thermo-catalytic conversion have an advantageous effect when used as asphalt binder modifiers to enhance tensile strength and/or as anti-stripping agents in asphalt cements or asphalt-containing roofing materials (hereinafter the term “asphalt binder modifier(s)” refers to compositions which are tensile strength modifiers or anti-stripping agents or both).
The asphalt binder modifiers of the current invention are derived from biomass T-C oil and are higher molecular weight components of the biomass T-C oil, that is those components having a boiling point of at least about 450° F. (232° C.), or at least about 650° F. (343° C.). The asphalt binder modifiers can comprise, consist of, or consist essentially of biomass T-C oil derived organic compounds having a boiling point of at least about 650° F. (343° C.) and having furan and phenol compounds as dominant species. At least about 10 weight percent of the asphalt binder modifier can be furan and phenol compounds. Generally, the amount of furan and phenol compounds can be less than about 40 weight percent, or can be less than about 20 weight percent, hence they can be present in an amount from about 10 weight percent to about 40 weight percent and can be from about 10 weight percent to about 20 weight percent. Additionally, the asphalt binder modifier can have an oxygen content less than about 20 weight percent, or at least about 4 weight percent and less than or equal to about 18 weight percent, or at least about 6 weight percent and less than or equal to about 14 weight percent. Also, the asphalt binder modifier can have an anhydro sugar content of less than about 5 weight percent, or less than about 1 weight percent.
The biomass T-C oil composition useful in the present invention can be produced by the biomass thermo-catalytic conversion process described above. The biomass T-C oil can be subsequently separated by a fractionation process into a high molecular weight fraction and a lower molecular weight fraction, wherein, in accordance with one embodiment, the high molecular weight fraction is used as the biomass T-C oil derived asphalt binder modifier, which can be without undergoing a hydrogenation or hydrogenolysis process, such as hydrotreating, prior to use as an asphalt binder modifier. Such fractionation process can be any fractionation process capable of separating out the target high molecular weight fraction.
The asphalt binder modifier will generally be blended with an asphalt to produce an asphalt binder composition prior to blending with an aggregate. Notwithstanding the above, in certain situations it may be desirable to blend the asphalt binder modifer with aggregate or a portion of the aggregate prior to blending with asphalt of additional aggregate. Whether used as a modifier or agent, the above described asphalt binder modifier can be useful in an amount of from about 1 weight percent to about 15 weight percent of the asphalt binder, preferably from about 3 weight percent to about 7 weight percent and more preferably from 4 weight percent to about 6 weight percent.
At least a portion of the biomass T-C oil can be at least partially hydrotreated to thereby form the asphalt binder modifier. Further, such asphalt binder modifier can have an oxygen content lower than the oxygen content of the biomass T-C oil. In addition, the oxygen content of the asphalt binder modifier can be less than about 10 weight %, or less than about 2 weight % oxygen, and the asphalt binder modifier can have a boiling point of at least about 650° F. The oxygen content of such asphalt binder modifier can also be in the range of from about 2 weight % to about 10 weight %, or from about 4 weight % to about 8 weight % oxygen.
In one such embodiment, the biomass T-C oil derived asphalt binder modifier, which can be for enhancing anti-stripping, can be produced by mixing an upgraded asphalt binder modifier which can comprise hydrocarbons that are essentially free of heteroatoms and which can comprise less than 1 weight percent oxygen (or a “hydrotreated fraction” of the biomass T-C oil) as a first component with the above described asphalt binder modifier as a second component (or a “non-hydrotreated fraction” of the biomass T-C oil). The hydrotreated fraction can be produced by hydrotreating (hydrogenolysis and hydrogenation) a portion of the above described asphalt binder modifier, such as by processing in a hydrotreater. Each of the fractions can have a boiling point of at least about 650° F. (343° C.). More specifically, the asphalt binder modifier of this embodiment can be obtained by: (i) hydrotreating a portion of the biomass T-C oil to produce a hydrotreated biomass T-C oil; (ii) separating a fraction having a boiling point of at least about 650° F. from the hydrotreated biomass T-C oil, thereby forming the first component; and (iii) separating a fraction having a boiling point of at least about 650° F. from biomass T-C oil, thereby forming the second component.
In this embodiment the hydrotreated fraction and non-hydrotreated fraction can both be present in an amount of about 1 weight percent to about 7 weight percent of the asphalt binder, or from about 2 weight percent to about 4 weight percent. The hydrotreated and non-hydrotreated fractions can also be present in nominally equal amounts with the total of both fractions being about 1 weight percent to about 15 weight percent of the asphalt binder composition, or from about 3 weight percent to about 7 weight percent, or from about 4 weight percent to about 6 weight percent.
In accordance with another such embodiment, it is within the scope of the invention that instead of hydrotreating only a portion of the biomass T-C oil, that the entire biomass T-C oil can be subjected to partial hydrogenation to reduce the oxygen content, followed by separating a fraction having a boiling point of at least about 650° F. from the partially hydrotreated biomass T-C oil, thereby forming the asphalt binder modifier which can have less than about 10 weight %, or less than about 2 weight % oxygen. This partially hydrotreated asphalt binder modifier can make up about 1 weight percent to about 15 weight percent of the asphalt binder composition, or from about 3 weight percent to about 7 weight percent, or from about 4 weight percent to about 6 weight percent.
Suitable grades of asphalt for use with the current invention included all Performance Grades and all paving or roofing grades having a PEN (penetration grade) greater than 5.
In an embodiment of the present invention, an asphalt concrete composition comprises, consists of, or consists essentially of an aggregate and an asphalt binder, which comprises, consists of, or consists essentially of asphalt and any of the above described asphalt binder modifiers. Suitable aggregates include one or more of the following: sand, gravel, limestone, dolomite, diabase, quartz, feldspar, stone chips, recycled asphalt pavement, recycled shingles, and crumb rubber. In addition, rheology modifier or other additives may be used including one or more of the following: SBS (styrene-butadiene-styrene), FT wax (Fischer-Tropsch wax), petroleum wax, other ASA additives (lime, organic amines), and the like. While it is presently preferred to mix the asphalt with the biomass T-C oil derived asphalt binder modifier prior to blending the resulting mixture with the aggregate, it is within the scope of this invention to mix the biomass T-C oil derived asphalt binder modifier first with the aggregate and then blending the resulting mixture with the asphalt. The asphalt concrete composition can comprise at least about 95 wt % of the aggregate and can comprise at least about 5 wt % of any of the asphalt binders as described above, and can also contain up to about 10 vol % air voids.
When the asphalt concrete composition, including any one of the asphalt binders described above, is contacted with water, the asphalt binder modifier reduces the stripping of the asphalt binder from the aggregate by the water, as compared to an asphalt concrete not including such an asphalt binder modifier.
Turning now to
The biomass conversion system 10 of
As depicted in
In one embodiment, it may be desirable to combine the biomass with a catalyst in the biomass feed system 14 prior to introducing the biomass into the biomass conversion reactor 16. Alternatively, the catalyst may be introduced directly into the biomass conversion reactor 16. The catalyst may be fresh and/or regenerated catalyst. The catalyst can be a heterogeneous acid catalyst; for example it may comprise a solid acid, such as Amberlyst-15, amorphous silica-alumina or a zeolite. Examples of suitable zeolites include ZSM-5, ZSM-11, ZSM-18, ZSM-22, ZSM-23, ZSM-48, Mordenite, Beta, Ferrierite, zeolite-X, and zeolite-Y. Additionally, the catalyst may comprise a super acid. Examples of suitable super acids include Nafion-H, sulfonated, phosphated, or fluorinated forms of zirconia, titania, alumina, silica-alumina, and/or clays. In another embodiment, the catalyst may comprise a solid base. Examples of suitable solid bases include metal oxides, metal hydroxides, and/or metal carbonates. In particular, the oxides, hydroxides, and carbonates of alkali metals, alkaline earth metals, transition metals, and/or rare earth metals are suitable. Other suitable solid bases are layered double hydroxides, mixed metal oxides, hydrotalcite, clays, and/or combinations thereof. In yet another embodiment, the catalyst can also comprise an alumina, such as alpha-alumina.
It should be noted that solid biomass materials generally contain minerals. It is recognized that some of these minerals, such as potassium carbonate, can have catalytic activity in the conversion of the biomass material. Even though these minerals are typically present during the chemical conversion taking place in the biomass conversion reactor 16, they are not considered catalysts.
The biomass feed system 14 introduces the biomass feedstock into a biomass conversion reactor 16. In the biomass conversion reactor 16, biomass is subjected to a conversion reaction that produces biomass T-C oil. The reactor 16 can be any system or device capable of thermo-catalytically converting biomass to biomass T-C oil. The biomass conversion reactor 16 can be, for example, a fluidized bed reactor, a cyclone reactor, an ablative reactor, or a riser reactor.
In one embodiment, the biomass conversion reactor 16 can be a riser reactor with the conversion reaction being catalytic enhanced fast pyrolysis or biomass thermo-catalytic cracking. As discussed above, the biomass thermo-catalytic conversion should occur in an oxygen-poor or, preferably, oxygen-free atmosphere. In one embodiment, biomass thermo-catalytic conversion is carried out in the presence of an inert gas, such as nitrogen, carbon dioxide, and/or steam. Alternatively, the biomass thermo-catalytic conversion can be carried out in the presence of a reducing gas, such as hydrogen, carbon monoxide, noncondensable gases recycled from the biomass conversion process, and/or any combination thereof.
The biomass thermo-catalytic conversion process is characterized by short residence times and rapid heating of the biomass feedstock. The residence times of the conversion can be, for example, less than 10 seconds, less than 5 seconds, or less than 2 seconds. The biomass thermo-catalytic conversion may occur at temperatures between 200 and 1,000° C., between 250 and 800° C., or between 300 and 600° C.
The catalyst can be used as a heat carrier material and introduced into reactor 16 via line 26 at sufficient temperature to insure that the reaction mixture reaches a temperature between 200 and 1,000° C., between 250 and 800° C., or between 300 and 600° C. In this embodiment, rapid heating of the solid biomass material can generally be accomplished by providing the solid biomass material in the form of particles having a low mean particle diameter. Preferably, the mean particle diameter of the biomass is less than about 2000 μm, and more preferably less than about 1000 μm. The pretreatment of the biomass material can help achieve the desired particle size.
Referring again to
As depicted in
The substantially solids-free fluid stream 20 exiting the separator system 19 can then be introduced into a water separator 30 for separation into a biomass T-C oil stream 31 and a water stream 32. The water separator can include, but is not limited to, a decanter, coalescing filter, or centrifuge. The biomass T-C oil stream 31 can then be introduced into a fluids separator (fractionator) 33. It is preferred that the biomass T-C oil stream 31 entering the fluids separator (fractionator) 33 has not previously been subjected to a hydrogenolysis and/or hydrogenation process such as, for example, hydrotreating. Within fluids separator 33, any remaining non-condensable gas is separated from the biomass T-C oil. Additionally, a low molecular weight fraction is separated from a high molecular weight fraction (boiling point at least about 650° F. (343° C.)). The fluids separator 33 can be any system capable of separating the biomass T-C oil stream 31 into a non-condensable gas fraction 40, low molecular weight fraction and high molecular weight fraction. Suitable systems to be used as the fluids separator 33 include, for example, systems for affecting separation by vacuum distillation, wiped film evaporation, fractional distillation, heated distillation, extraction, membrane separation, partial condensation, and/or non-heated distillation and can also be a combination of such separation techniques. As shown in
The low molecular weight renewable biomass T-C oil composition is removed from fluids separator 33 via line 34 and the high molecular weight renewable biomass T-C oil composition is removed from fluids separator 33 via line 38. The high molecular weight biomass T-C oil 38 can be utilized as the biomass T-C oil derived asphalt binder modifier of the current invention, as described above.
Turning now to
The biomass conversion system 210 of
As depicted in
The catalyst useful in this biomass conversion system 210 can be the same as that described above in
Referring again to
As depicted in
The substantially solids-free fluid stream 220 exiting the separator system 219 can then be introduced into a water separator 230 for separation into a biomass T-C oil stream 231 and a water stream 232. The water separator 230 can include, but is not limited to, a decanter, a coalescing filter, and/or a centrifuge. At least a portion of the biomass T-C oil stream 231 can then be introduced into a hydrotreater system 233. The hydrotreater system 233 can include one or more hydrotreaters, each potentially having multiple reaction zones.
The portion of the biomass T-C oil stream 231 sent to hydrotreater system 233 via line 231 is preferably representative in composition as that of the whole biomass T-C oil. It is preferred that the biomass T-C oil contained in stream 231 and entering the hydrotreater system 233 has not previously been subjected to a hydrogenolysis and/or hydrogenation process such as, for example, hydrotreating. The biomass T-C oil charged to hydrotreater system 233 via line 231 is at least partially hydrotreated in hydrotreater system 233, forming a hydrotreater liquid effluent 234 comprising either a partially hydrotreated biomass T-C oil or an at least substantially fully hydrotreated biomass T-C oil. The hydrotreater system 233 can also include the collection of unreacted hydrogen present in the hydrotreater liquid effluent 234, and recycle of such hydrogen within the hydrotreater system 233.
The hydrotreater liquid effluent 234 is then separated in a first fluids separator 236. A first low molecular weight fraction 242 of the hydrotreater liquid effluent 234 (the hydrotreated biomass T-C oil) is separated from a first high molecular weight fraction 244 (boiling point at least about 450° F. (232° C.), or preferably at least about 650° F. (343° C.)). The first fluids separator 236 can be any system capable of separating the hydrotreater effluent 234 into a first low molecular weight fraction and a first high molecular weight fraction. Suitable systems to be used as the first fluids separator 236 include, for example, systems for affecting separation by vacuum distillation, wiped film evaporation, fractional distillation, heated distillation, extraction, membrane separation, partial condensation, and/or non-heated distillation and can also be a combination of such separation techniques.
The first high molecular weight biomass T-C oil composition 244 can be utilized as the biomass T-C oil derived asphalt binder modifier of the current invention.
Optionally, at least a portion of the biomass T-C oil 231 can be introduced into a second fluids separator 246 via lines 231 and 248. The portion of the biomass T-C oil sent to second fluids separator 246 via lines 231 and 248 is preferably representative in composition as that of the whole biomass T-C oil. It is preferred that the biomass T-C oil contained in stream 248 and entering the second fluids separator 246 has not previously been subjected to a hydrogenolysis and/or hydrogenation process such as, for example, hydrotreating. Within second fluids separator 246 a second low molecular weight fraction 254 is separated from a second high molecular weight fraction 256 (boiling point at least about 450° F. (232° C.), or at least about 650° F. (343° C.)). The second fluids separator 246 can be any system capable of separating the biomass T-C oil contained in stream 248 into a second low molecular weight fraction and a second high molecular weight fraction. Suitable systems to be used as the second fluids separator 246 include, for example, systems for affecting separation by vacuum distillation, wiped film evaporation, fractional distillation, heated distillation, extraction, membrane separation, partial condensation, and/or non-heated distillation and can also be a combination of such separation techniques.
When the hydrotreater effluent 234 is the at least substantially fully hydrotreated biomass T-C oil, then the first high molecular weight biomass T-C oil composition 244 (at least substantially fully hydrotreated) can be utilized as a first component of the biomass T-C oil derived asphalt binder modifier, and the second high molecular weight biomass T-C oil composition 256 (non-hydrotreated) can be utilized as a second component of the biomass T-C oil derived asphalt binder modifier by: combining the first high molecular weight biomass T-C oil composition 244 with the second high molecular weight biomass T-C oil composition 256 via lines 244 and 256, thereby forming the biomass T-C oil derived asphalt binder modifier of the current invention. Optionally, in place of or in combination with the biomass T-C oil stream 231 feed to hydrotreater system 233, at least a portion of the second high molecular weight biomass T-C oil composition 256 can be introduced to hydrotreater system 233 via lines 256 and 258 wherein at least a portion of the second high molecular weight biomass T-C oil composition 256 is either partially or substantially fully hydrotreated, forming an alternate hydrotreater effluent 260. The alternate hydrotreater effluent 260 can be utilized as the biomass T-C oil derived asphalt binder modifier of the current invention, or combined with a portion of the first high molecular weight biomass T-C oil composition 244 via lines 260, 262, and 244, and/or combined with a portion of the second high molecular weight biomass T-C oil composition 256 via lines 256, 260 and 264, thereby forming the biomass T-C oil derived asphalt binder modifier of the current invention.
In accordance with another embodiment, a roofing material can comprise felt and a mixture of granules and an asphalt binder containing any of the above described biomass T-C oil derived asphalt binder modifiers. The felt can be any material typically used as a substrate material in the roofing industry, and more particularly can be selected from the group consisting of cellulosic fibers, glass fibers, and combinations thereof. The granules can be any such materials typically used in the roofing industry, and more particularly can be mineral granules and/or granules in the form of fines. The roofing material described above can have improved anti-stripping properties as compared to an asphalt-containing roofing material that does not include any of the above described biomass T-C oil derived asphalt binder modifiers.
Table 1 summarizes the five different asphalt binders that were derived from lignocelluloses by either fast pyrolysis or biomass catalytic conversion processing followed by some type of fractionation to isolate the high molecular weight components (asphalt binder).
Examples 1 through 5 were all produced from Southern Yellow Pine chips (a lignocellulosic feedstock). The chips were dried to a nominal 5 weight percent moisture content and sized using a commercial hammer mill to less than 5 mm.
Example 1 is a light distillation residue from renewable T-C oil. For this Example, the lignocellulosic feedstock was converted in a biomass catalytic conversion process in a 10 bbl/day continuous fluidized catalytic cracker using an aluminosilicate catalyst. A riser reactor was used in the conversion process with the riser outlet being at 1000° F. Next, after cooling and removal of solids and non-condensable gases, the free water byproduct was separated from the oil. The T-C oil was then charged to a wiped film evaporator (less than 3 theoretical plates) and the high molecular weight residue was separated from the distillate at a pressure of 10 torr. This material (Example 1) had a nominal initial boiling point IBP of 450° F. by Gel Permeation Chromatography using polystyrene molecular weight standards.
Example 2 is a heavy residue from renewable T-C oil. Example 2 was prepared in the same way as Example 1 except a batch vacuum distillation unit was used (vs. a wiped film evaporator) to isolate the high molecular weight residue. This residue (Example 2) had a nominal IBP of 650° F. (343° C.) by distillation conditions (boiling point was determined under a vacuum and then the nominal IBP at atmospheric pressure was calculated to be 650° F. (343° C.)).
Example 3 is a heavy residue from pyrolysis oil. For Example 3, the lignocellulose feedstock was converted in a fast pyrolysis using fluidized sand (no catalyst) as the heat transfer media in a unit designed to give equivalent performance to a thermo-catalytic conversion unit. Like with Example 2, a batch vacuum distillation unit was used to isolate the high molecular weight residue.
Example 4 is a heavy residue from a hydrotreated renewable T-C oil. Like Examples 1 and 2, the lignocellulosic feedstock was converted in a biomass catalytic conversion process using the same catalyst. After removing the free water byproduct by decanting, the T-C oil was fed to a fixed bed high-pressure hydrotreater (HDT) where the oxygen level was reduced to less than 1 weight percent. The HDT liquid product was isolated from the gases and then fractionated in a batch vacuum distillation unit to produce a 650° F.+ (343° C.+) residue (Example 4).
Example 5 represents a partially hydrotreated sample and was derived by mixing a sample of Example 2 with a sample of Example 4 to produce a 50/50 weight percent blend.
In the examples below, the neat binder used in the evaluation was PG 64-22 obtained from the Paulsboro, N.J. refinery of NuStar Asphalt, LLC. Table 2 summarizes the performance grading properties of this binder. The neat binder has a continuous performance grade of PG 67.2 (20.8)-26.4.
A coarse, dense-graded 9.5 mm mixture composed of diabase coarse and natural sand fine aggregate was used in the examples below. This mixture was selected because the diabase aggregate is moisture sensitive resulting in typical tensile strength ratios of approximately 70 percent when tested in accordance with the American Association of State Highway and Transportation Officials AASHTO T283 without anti-strip agents. Table 3 summarizes pertinent volumetric properties of the mixture.
Each of the five examples were blended at 5 weight percent concentration with neat NuStar PG 64-22 binder and graded in accordance with AASHTO R29. For Examples 2, 3, 4 and 5, a 20 weight percent concentrate was prepared by heating both the cellulosic pyrolysis binder and the neat binder to 175° C. and mixing for 30 minutes with a mechanical stirrer. After the concentrate cooled, it was reheated to 160° C. and additional neat binder also heated to 160° C. was added to reach the target concentration of 5 weight percent. For Example 1, the same process was used; however, lower temperatures were used because Example 1 fumed at temperatures higher than 120° C. Accordingly, a temperature of 115° C. was used for the initial mixing of 20 weight percent concentrate and a temperature of 120° C. was used for the subsequent addition of neat binder.
AASHTO T283 moisture sensitivity testing was conducted on the 5 weight percent blends of the Example 1-5 asphalt binders and on a neat NuStar PG 64-22 binder (Control). The results are shown in
Additionally, the superior performance of Example 2 is surprising when the compositions of the Examples are compared (see Table 1). Example 2 performed better than both Examples 3 and 4. Examples 2 and 4 have lower oxygen content and lower content of anhydro sugars than Example 3. Additionally, Examples 2 and 4 are not water-soluble where-as Example 3 is water-soluble. Also, the oxygen content for Example 2 (12.0 wt %) is intermediate to the oxygen contents for Example 3 (28.6 wt %) and for Example 4 (0.4 wt %). Thus, the fact that the tensile strength performance for Example 2 exceeds that for Examples 3 and 4 is unexpected. The compositional differences between Examples 2 and 3, when viewed in light of the performance differences between Examples 2 and 4, further evidences that the performance of non-catalytic pyrolysis oils are not indicative, or predictive, of the performance of a biomass T-C oil as an asphalt binder modifier.
While the technology has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the technology as defined by the appended claims
As used herein, the terms “a,” “an,” “the,” and “said” means one or more.
As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.
As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up of the subject.
As used herein, the terms “containing,” “contains,” and “contain” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided below.
As used herein, the terms “having,” “has,” and “have” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above
As used herein, the terms “including,” “includes,” and “include” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above.
The preferred forms of the invention described above are to be used as illustration only, and should not be used in a limiting sense to interpret the scope of the present invention. Modifications to the exemplary embodiments, set forth above, could be readily made by those skilled in the art without departing from the spirit of the present invention.
The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as it pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.
The present application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 61/513,078, filed Jul. 29, 2011. The entirety of which is hereby expressly incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61513078 | Jul 2011 | US |
