Process for modifying bitumen using oil with reduced Polycyclic Aromatic Hydrocarbons (PAH) content obtained from pyrolysis of scrap tyres
阅读说明：本技术 使用具有从废轮胎热解得到的减少多环芳烃(pah)含量的油使沥青改性的方法 (Process for modifying bitumen using oil with reduced Polycyclic Aromatic Hydrocarbons (PAH) content obtained from pyrolysis of scrap tyres ) 是由 盖伦·L·鲍姆加德纳 于 2018-12-03 设计创作，主要内容包括：使用来自废轮胎热解的分馏产物使沥青粘结剂改性,采用以下初始步骤：i)在与这种沥青粘结剂分开的情况下,至少部分地热解整个橡胶制品或尺寸减小的橡胶颗粒,以提供一种或多种热解橡胶馏分,所述一种或多种热解橡胶馏分包括具有选定的最小初始沸点或闪点的热解油馏分；并且ii)从这种热解油馏分去除一些或所有多环芳烃(PAH)化合物,以提供可以与沥青粘结剂结合以提供改性沥青组合物的减少PAH的且优选半透明的热解油馏分。(Asphalt binder modification using fractionated products from pyrolysis of scrap tires using the following initial steps: i) pyrolyzing, at least partially, the entire rubber article or rubber particles of reduced size, separately from such asphalt binder, to provide one or more pyrolysis rubber fractions comprising a pyrolysis oil fraction having a selected minimum initial boiling point or flash point; and ii) removing some or all of the Polycyclic Aromatic Hydrocarbon (PAH) compounds from such pyrolysis oil fraction to provide a PAH-reduced and preferably translucent pyrolysis oil fraction that can be combined with an asphalt binder to provide a modified asphalt composition.)
1. A method for modifying an asphalt binder, comprising the steps of:
i) pyrolyzing, at least partially, the entire rubber article or rubber particles of reduced size separately from such asphalt binder to provide one or more pyrolysis rubber fractions comprising a pyrolysis oil fraction having a selected minimum initial boiling point or flash point;
ii) removing at least some Polycyclic Aromatic Hydrocarbon (PAH) compounds from such pyrolysis oil fraction to provide a PAH-reduced pyrolysis oil fraction capable of combining with an asphalt binder to provide a modified asphalt composition.
2. The method of claim 1, further comprising combining the PAH reduced pyrolysis oil fraction with the asphalt binder to provide a modified asphalt composition.
3. The method of claim 1 or claim 2, wherein one or more of the following steps are performed to remove at least some PAH compounds:
i) fractionating the pyrolysis oil fraction in a temperature range that removes a desired initial boiling point or a desired minimum flash point pyrolysis oil fraction and leaves at least some PAH compounds;
ii) solvent extracting the pyrolysis oil fraction by using one or more solvents that remove the desired initial boiling point or the desired minimum flash point pyrolysis oil fraction and leave at least some PAH compounds;
iii) centrifuging the pyrolysis oil fraction to separate a desired initial boiling point or a desired minimum flash point pyrolysis oil fraction from a fraction containing concentrated PAH compounds; or
iv) subjecting the pyrolysis oil fraction of the desired initial boiling point or the desired minimum flash point to wiped film evaporation and leaving at least some PAH compounds.
4. The method of claim 3, wherein at least some PAH compounds are removed by fractionating the pyrolysis oil fraction over a range of temperatures.
5. The process of claim 3 or 4, wherein at least some of the PAH compounds are removed by solvent extraction.
6. The method of any one of claims 3 to 5, wherein at least some PAH compounds are removed by centrifugation.
7. The method of any one of claims 3 to 6, wherein at least some PAH compounds are removed by wiped film evaporation.
8. The method of any of claims 3 to 6, wherein at least some PAH compounds are removed by filtering carbon solids from the pyrolysis oil.
9. The process of any of the preceding claims, wherein the total PAH content in the reduced PAH pyrolysis oil fraction is less than about 100ppm by weight.
10. The process of any of the preceding claims, wherein the total PAH content in the reduced PAH pyrolysis oil fraction is less than about 10ppm by weight.
11. The method of any of the preceding claims, wherein the PAH-reducing pyrolysis oil fraction comprises less than about 10ppm by weight of benzo (a) pyrene, benzo (e) pyrene, benzo (a) anthracene, anthracene,Total concentration of benzo (b) fluoranthene, benzo (j) fluoranthene, benzo (k) fluoranthene, and dibenzo (a, h) anthracene.
12. The method of any of the preceding claims, wherein the PAH-reduced pyrolysis oil fraction comprises less than about 1ppm by weight of benzo (a) pyrene.
13. The method of any of the preceding claims, wherein the PAH-reduced pyrolysis oil fraction comprises less than about 5 wt% carbon black solids.
14. The method of any of the preceding claims, wherein the reduced PAH pyrolysis oil fraction comprises less than about 0.5 wt% carbon black solids.
15. The method of any of the preceding claims, wherein the PAH-reduced pyrolysis oil fraction is translucent.
16. The process of any of the preceding claims, wherein the PAH-reduced pyrolysis oil fraction has an open cup flash point of at least 50 ℃.
17. The process of any of the preceding claims, wherein the PAH-reduced pyrolysis oil fraction has an open cup flash point of at least 90 ℃.
18. The process of any of the preceding claims, wherein the reduced PAH pyrolysis oil fraction is combined with a lower temperature molten asphalt binder such that the asphalt binder acts as a quencher for the pyrolysis oil fraction.
19. The process of any of the preceding claims, wherein the PAH-reduced pyrolysis oil fraction and one or more synthetic polymers are combined with an asphalt binder to provide a polymer-modified asphalt composition.
20. The method of any one of claims 2 to 19, further comprising using the modified asphalt composition to prepare an asphalt emulsion for road construction or maintenance.
21. The method of any of claims 2 to 20, further comprising using the modified asphalt composition in a pavement maintenance program comprising:
a) spraying a heated liquid pavement maintenance binder comprising the modified asphalt composition onto a pavement surface; and is
b) Applying pieces of aggregate to the binder to provide a sealed non-slip surface.
22. The method of claim 21, wherein the temperature of the pavement maintenance binder is from about 250 ℃ to 325 ℃.
23. The method of claim 21, wherein the pavement maintenance binder comprises a bitumen emulsion having a temperature of from about 4 ℃ to about 100 ℃.
24. The method of any one of claims 2 to 20, further comprising using the modified asphalt composition in an asphalt paving process comprising:
a) mixing aggregate and a modified asphalt binder comprising the reduced PAH pyrolysis oil fraction to form an asphalt mixture comprising aggregate coated with the modified asphalt binder; and is
b) Compacting the asphalt mixture to provide an asphalt pavement having an in situ density value of less than 10% in situ air gap for the compacted asphalt mixture.
25. A modified asphalt binder prepared according to any one of claims 2 to 20 and comprising a PAH-reducing pyrolysis oil.
26. An asphalt paving mixture comprising the modified asphalt binder prepared according to claim 25.
Technical Field
The present invention relates to modified asphalt binders for use in asphalt paving mixtures.
Background
Asphalt concrete (also known as asphalt pavement) is a composite material comprising a mineral aggregate and an asphalt (bitumen) binder which hardens to form a strong surface. Asphalt binder modification can be used to improve the performance of asphalt concrete, for example by enhancing mixing performance or reducing or delaying three common types of asphalt concrete deterioration: deformation (rutting and jostling), cracking (due to repeated loading and low temperatures), and general deterioration (loosening and spalling). The deterioration of the road surface network coupled with the increased material costs makes the modification of asphalt binders desirable.
Passenger cars and trucks on U.S. highways wear millions of tires each year, which makes the disposal of used tires a significant environmental challenge. Rubber recovered from scrap tires can be used as an asphalt binder modifier in the production of Hot Mix Asphalt (HMA), Warm Mix Asphalt (WMA), cold mix asphalt, and asphalt pavement maintenance products. Asphalt modification currently consumes about 2% of the scrap tire market, totaling about 68,000 tons per year, or about 420 ten thousand tires.
Recycled tire rubber is produced from whole scrap tires by mechanical shearing and grinding to obtain rubber or crumb tire rubber of reduced size. There are two general particle size classifications for this size reduced rubber: "ground" rubber (also known as ground tire rubber or GTR) of 2.0mm (10 mesh) or less, "coarse" rubber greater than 2.0 millimeters (10 mesh) and a maximum dimension of 12.75mm (0.5 inches). For modified asphalt binders used in road construction, the size range of the size-reduced rubber is typically from about 1.5mm (1500 μm) down to about 420 μm (i.e., 15 mesh to 40 mesh), with limited use at finer sizes down to 177 μm and 125 μm (80 mesh and 120 mesh).
Two main methods are commonly used to incorporate tire rubber into asphalt concrete. These processes are commonly referred to as "dry" and "wet" processes. Dry methods involve adding GTR to the asphalt concrete mix during production, usually before introducing the required asphalt binder. The wet process involves mixing tire rubber (usually GTR) with an asphalt binder and allowing a specified reaction time before mixing the tire rubber modified binder with the aggregate. Two types of wet processes are generally used: "asphalt rubber" (AR) is commonly referred to as "wet process" or "McDonald process", while "rubber modified asphalt" (RMA) is also referred to as "end blend".
Tire rubber can also be incorporated into solvents (e.g., petroleum distillates) to produce modified petroleum distillate products that can be used for a variety of purposes. The modified petroleum distillate may be mixed, for example, with asphalt and aggregate to make asphalt concrete, or may be used to manufacture various asphalt repair products, including cutback asphalt, asphalt emulsions, asphalt surface treatments, and other products familiar to those of ordinary skill in the art.
Patents or publications relating to bitumen modification using rubber products, waste rubber products or materials derived from rubber products include U.S. Pat. No. 3,891,585(McDonald '585), 3,919,148(Winters et al), 4,069,182 (McDonald' 182), 4,085,078(McDonald '078), 4,430,464 (oviner), 4,485,201(Davis), 4,588,634(Pagen et al), 5,070,109(Ulick et al), 5,230,777(Jarrell), 5,270,361 (eondul et al), 5,334,641(Rouse), 5,397,818 (flaniganan' 818), 5,492,561(Flanigan '561), 5,583,168 (Flanigan' 168), 6,221,329B 1(Faulkner et al), 1 (nichol 1B 1 (nichol et al '861), 1B 1(Burris et al' 659), bullan B72 (cath B1), 1B 36011 (3676B 1B 36521), and 3676B 1 (flanger et al), 1B 1 (1B 36521, 1B 1 (1B 1, 1B 1, 3676B 36521 and 1 (flanger et al); U.S. patent application publication No. 2004/0182001 a1 (masterore et al); international application publication No. WO 95/20623; and Investigating the influencing of a modifier for an aphalter (Road Materials and fashion Design,17:4,825-840(2016)) in Fini et al; the Characterization and evaluation of group and corner rubber polymers for asphal condrete (Ph. university of Mississippi State university, 2015); vacuum pyrolysis of used tissue End-uses for oil carbon black products (J, anal. Appl. pyrolysis 51,201-221(1999)) by Roy and outstanding tissue area used in asphal (Asphal, 25:3,7-14(2010)) by Walker. Some of the methods described in these documents require extended processing times, extensive heating (and consequent degradation) of the asphalt binder, or the production of by-products that must be handled separately and some of them add significant amounts of carbon black or rubber to the asphalt.
In light of the foregoing, it will be recognized that there is a need in the art for improved reclaimed rubber asphalt modifiers. Such reclaimed rubber asphalt modifiers and methods of making and using the same are disclosed and claimed herein.
Disclosure of Invention
The present invention provides a method for modifying asphalt binders using fractionated oil products obtained from pyrolysis of scrap tires. In a first aspect, the method comprises the steps of: i) pyrolyzing, at least partially, the entire rubber article or rubber particles of reduced size separately from such asphalt binder to provide one or more pyrolysis rubber fractions comprising a pyrolysis oil fraction having a selected minimum initial boiling point or flash point; and ii) removing at least some Polycyclic Aromatic Hydrocarbon (PAH) compounds from such pyrolysis oil fraction to provide a PAH-reduced and preferably translucent pyrolysis oil fraction that can be combined with an asphalt binder to provide a modified asphalt composition.
In a second aspect, the removal of at least some of the PAH compounds disclosed is performed by one or more of the following steps:
I) fractionating the pyrolysis oil fraction in a temperature range that removes a desired initial boiling point or a desired minimum flash point pyrolysis oil fraction and leaves at least some PAH compounds;
ii) solvent extracting the pyrolysis oil fraction by using one or more solvents that remove the desired initial boiling point or the desired minimum flash point pyrolysis oil fraction and leave at least some PAH compounds;
iii) centrifuging the pyrolysis oil fraction to separate a desired initial boiling point or a desired minimum flash point pyrolysis oil fraction from a fraction containing concentrated PAH compounds; or
iv) subjecting the pyrolysis oil fraction of the desired initial boiling point or the desired minimum flash point to wiped film evaporation and leaving at least some PAH compounds.
In some embodiments, the removed pyrolysis oil fraction comprises primarily components having an initial boiling point or flash point in the temperature range of 150 ℃, 200 ℃, or 250 ℃.
In another aspect, the disclosed pyrolysis oil fraction is combined with (e.g., injected into) a lower temperature molten asphalt binder such that the asphalt binder acts as a quencher for the pyrolysis oil fraction.
In another aspect, the disclosed pyrolysis oil fraction and one or more synthetic polymers are combined with an asphalt binder to provide a polymer modified asphalt composition.
The present invention also provides a modified asphalt binder composition comprising such a PAH-reducing oil fraction. In addition, the present invention provides an asphalt paving mixture comprising such a modified asphalt binder composition and aggregate. The disclosed modified asphalt binder compositions and asphalt paving mixtures can be used in asphalt construction products for a variety of purposes including paving, roofing, waterproofing, and protective coatings.
The disclosed methods and compositions may use materials obtained by pyrolysis of scrap tires or other post-consumer rubber products to modify asphalt materials. The pyrolysis step is carried out separately from the modification of the bituminous material. Benefits of doing so may include one or more of reducing processing time, reducing temperature, and increasing plant safety due to reduced risk of fire. The disclosed methods and compositions also enable improved control of ingredients (e.g., coke content, low flash point components, or PAH compounds) in the modified asphalt material, thereby providing benefits such as improved product stability due to reduced particle separation and precipitation, reduced product flammability due to removal of low flash point ingredients, and improved product safety due to reduced PAH content.
Definition of
In this specification, unless explicitly stated otherwise, the following terms have the following meanings:
the use of endpoints to indicate a range of numbers includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). All percentages are by weight unless otherwise indicated.
The term "about" refers to a range of numbers that can be considered equivalent to the recited value (e.g., having the same function or result), and includes values that are rounded to the nearest significant figure.
The term "char" refers to a combustible solid organic residue remaining after thermal conversion of a rubber product (e.g., whole tires, ground tire rubber, or other whole or comminuted rubber products) using pyrolysis or other at least partially destructive, incomplete oxidation thermal conversion techniques.
The terms "tar" and "pyrolysis oil" are used interchangeably and refer to a combustible liquid organic residue remaining after thermal conversion of a rubber product (e.g., whole tire, ground tire rubber, or other whole or shredded rubber product) using pyrolysis or other at least partially destructive, incomplete oxidation thermal conversion techniques.
The term "polymer" independently includes homopolymers, copolymers, terpolymers, block copolymers, segmented copolymers, graft copolymers, and any mixtures or combinations thereof.
The terms "polycyclic aromatic hydrocarbon", "PAH", "polycyclic aromatic", and "PCA" are used interchangeably and refer to compounds that can be classified as carcinogenic, mutagenic, or geminalA toxic polycyclic compound. These compounds that can be found in waste tires include benzo (a) pyrene (BaP, CAS number 50-32-8), benzo (e) pyrene (BeP, CAS number 192-97-2), benzo (a) anthracene (BaA, CAS number 56-55-3),(CHR, CAS number 218-01-9), benzo (b) fluoranthene (BbFA, CAS number 205-99-2), benzo (j) fluoranthene (BjFA, CAS number 205-82-3), benzo (k) fluoranthene (BkFA, CAS number 207-08-9), and dibenzo (a, h) anthracene (DBAhA, CAS number 53-70-3). The presence and amounts of these compounds can be assessed using gas chromatography/mass spectrometry (GC/MS) procedures familiar to those of ordinary skill in the art of analytical chemistry.
The term "post-consumer waste" refers to waste produced by the end-use consumer of a stream of matter. Post-consumer waste includes trash or material produced from trash that is routinely discarded by individuals. Post-consumer waste can be distinguished from "pre-consumer waste," which is manufacturing waste that can be reintroduced into the manufacturing process. The pre-consumer waste polymers are typically of natural or synthetic origin, while the post-consumer polymers may typically be of natural, synthetic or both natural and synthetic origin, and may contain other compounds or materials. Waste tire rubber can be considered post-consumer waste comprising post-consumer polymers.
The term "pyrolysis" refers to actual pyrolysis or any other thermal conversion technique that does not completely oxidize, which at least partially destroys organic material and enables the separation or recovery of one or more organic components present in or useful for making such organic material.
In the case of oil or other liquid products, the term "translucent" means that when a standard 150mm high 3514 mm inside diameter glass test tube is filled with liquid and placed on white paper (on which the phrase "Can you read this" printed in black 22 letters is written), the letter Can be viewed through the tube under normal overhead room lighting conditions.
Drawings
FIG. 1 is a flow diagram illustrating steps or components that may be used in the disclosed method.
Like reference symbols in the various drawings indicate like elements. Elements in the figures are not drawn to scale.
Detailed Description
Referring to fig. 1, scrap tires 101 may be processed 103 to convert tires 101 into reduced size rubber or GTR, which may then be pyrolyzed 105. Alternatively, the tyre 101 may be pyrolysed 105 in its entirety, without a prior size reduction step. Pyrolysis 105 produces components including off-gas 107, pyrolysis oil 108, carbon solids 109, and ash (not shown in fig. 1). The exhaust gases 107 may be incinerated, combusted, or compressed, for example, to provide a fuel that may be used in the pyrolysis 105 or any other process that uses thermal energy. The carbon solids 109 may be collected as carbon black and used, for example, as a component in the manufacture of tires or other rubber products.
The pyrolysis oil 109 is preferably fractionated 113 to remove a light oil fraction 115, which may have an initial boiling point of less than 350 ℃ (662 ℃), for example. The light oil fraction 115 may be used as a burner fuel or sold for use as a solvent. Heavy oil fraction 117, for example, may have an initial boiling point greater than 350 ℃ (662 ° f), which is further treated to remove at least some weight proportion and preferably most weight proportion of PAH compounds in oil 117. A variety of PAH removal techniques can be employed, including further fractionation 119 to separate oil components falling within the desired boiling temperature range (e.g., oils with initial boiling points of 350 ℃ (662 ° f) to 600 ℃ (1112 ° f)), solvent extraction 121, centrifugation 123, or wiped film evaporation 125. As understood by one of ordinary skill in the art, PAH removal is not limited to techniques 119 through 125, and may include any suitable technique whereby PAH compounds in the heavy oil fraction 117 may be at least partially, and preferably mostly or completely, removed from the end-use product 127. Additionally, two or more PAH removal techniques (including any two or more of the techniques 119 to 125) may be combined to provide more complete or economical PAH removal. For example, the heavy oil fraction 117 may be subjected to further fractionation 119 followed by solvent extraction 121 to remove a greater proportion of PAH compounds than is achieved using further fractionation or solvent extraction alone.
In the process of removing PAH, dissolved or suspended rubber materials and suspended carbon particles in the heavy oil fraction 117 will also typically be removed or otherwise separated. Such rubber materials and carbon particles may, for example, be concentrated in black oil residual by-product 129. Typically, the rubber and carbon materials are present in concentrations such that heavy oil fraction 117 and residual black oil by-product 129 are opaque black liquids. Filtration may also be used to remove suspended rubber material and suspended carbon particles. In a preferred embodiment, the one or more PAH removal techniques selected remove sufficient dissolved or suspended rubber material and sufficient suspended carbon particles from the heavy oil fraction 117 so that the oil 117 will transition from an opaque black liquid to a light colored (e.g., amber and optionally translucent) end-use product 127.
Various reduced mass or size rubber articles or rubber particles may be used in the disclosed invention. Whole (and preferably ground) scrap or scrap tires are a particularly desirable source of rubber. Other sources include waste from tire retreading facilities, used gaskets and seals, and used membranes for waterproofing, roofing membranes, and other rubber-containing products. For size reduced rubbers, various particle sizes (including GTR and coarse rubber particle sizes) may be used. Coarse rubber or large size GTR particles may be preferred since additional grinding is required to obtain uniform small particles, smaller sizes generally being more costly. Larger particle sizes are also preferred when it is desired to only partially pyrolyze the rubber, with solid, non-pyrolyzed or incompletely pyrolyzed rubber particles remaining in the solid product stream, which is also added to or combined with the asphalt binder. Such non-pyrolyzed or incompletely pyrolyzed rubber particles may impart beneficial flexibility, impact resistance, or crack bluntness to the modified asphalt composition.
The pyrolysis oil fraction 109 may also contain sufficient rubber particles, the pyrolysis oil fraction may be referred to as "liquefied rubber" or "L R". carbon solids fraction 111 may be referred to as "coke", "carbon char" (carbon char), "tire derived coke" or "tire derived carbon char", and generally contains a significant amount of rubber charge.
In a preferred embodiment, the pyrolysis process time, temperature, and vacuum or pressure are adjusted to produce a thermal reactor output suitable for injecting the PAH reduced pyrolysis oil fraction directly into asphalt as an asphalt modifier. In such embodiments, the scrap tire rubber may or may not be fully pyrolyzed, but may also be combined with the asphalt binder. Modified asphalt made using partially pyrolyzed rubber may have elasticity and other properties that are not achievable in modified asphalt made using other tire rubber asphalt modification processes in which the rubber is completely degraded to low molecular weight species.
As noted above, the reduction or removal of PAH compounds may be performed using methods including fractional distillation, solvent extraction, centrifugation, and wiped film evaporation. Fractionation of the thermal cracked oil 113 and further fractionation of the heavy oil fraction 117 uses a selected temperature range to optimize the yield of the end use product 127, which represents a particularly preferred process. For example, fractionation may be performed to capture the portion of heavy oil fraction 117 having the following initial boiling points: at least about 300 ℃, at least about 310 ℃, at least about 320 ℃, at least about 330 ℃, at least about 340 ℃, at least about 350 ℃, at least about 360 ℃, at least about 370 ℃, at least about 380 ℃, at least about 390 ℃, or at least about 400 ℃. The upper limit of the fractionation range may, for example, correspond to an initial boiling point of about 550 ℃, about 560 ℃, about 570 ℃, about 580 ℃, about 590 ℃, about 600 ℃, about 610 ℃, about 620 ℃, about 630 ℃, about 640 ℃, or about 650 ℃.
When solvent extraction is used for the reduction or removal of PAH compounds, the solvent or solvents used and the temperature and pressure at which the solvent extraction is performed may be selected based on a variety of factors as will be understood by one of ordinary skill in the art. For example, the solvents may be selected based on solubility or lack of solubility of the polycyclic aromatic compound in these solvents or based on solubility or lack of solubility of the desired asphalt-modifying component present in the heavy oil fraction 117 in these solvents. Also, the selected temperature can be at, above, or below room temperature (25 ℃), and if desired, can be at supercritical fluid temperature. Exemplary solvents include: alkanes, such as heptane (B.P, 98 ℃), octane (B.P.126 ℃), mineral spirits (B.P.140-300 ℃) and mixtures thereof; aromatic hydrocarbons, including toluene (B.P.110 deg.C), bisToluene (B.P.140 ℃ C.) and paraffin (B.P.60-90 ℃ C.), cyclic compounds such as N-methyl-2-pyrrolidone (B.P.202 ℃ C.) and furfural (B.P.162 ℃ C.), dimethyl sulfoxide (B.P.189 ℃ C.), commercially available materials such as the "AROMATIC" series of fluids from Exxon Mobil (e.g., AROMATIC 150 and AROMATIC 200) and SHE LL SO L from Shell chemical companyTMSeries of fluids (e.g. SHE LL SO L A100 and SHE LL SO L A150) and mixtures thereof, petroleum solvents including petroleum naphtha, VM&P naphtha, Stoddard solvent, kerosene (B.P.150 deg.C), and mixtures thereof, solvents of vegetable origin including turpentine (B.P.150-180 deg.C), ketones including methyl ethyl ketone (B.P.80 deg.C), methyl isobutyl ketone (B.P.117 deg.C), methyl isoamyl ketone (B.P, 144 deg.C), methyl amyl ketone (B.P.150 deg.C), cyclohexanone (B.P.156 deg.C), isobutyl ketone (B.P.168 deg.C), methyl hexyl ketone (B.P.173 deg.C), methyl heptyl ketone (B.P.192 deg.C), and mixtures thereof, aromatic alcohols such as benzyl alcohol (B.P.203-205 deg.C), toluene alcohol, and the like, alcohol ethers, esters, and mixed ethers and esters such as ethylene glycol (B.P.195 deg.C), propylene glycol (B.P.C), 1, 3-butylene glycol (B.P, 204 deg.C), diethylene glycol (B.P.P.P.P.245 deg.C), hexylene glycol (B.C), and mixtures thereof, commercially available from Nostoddard company B.C, 2 deg.CTMAnd CARBITO LTMSolvent series and glyme (glyme) and diglyme (diglyme) solvent series available from clariant corporation; and other fluids such as supercritical carbon dioxide.
When centrifugation is used for the reduction or removal of PAH compounds, the treatment conditions may be selected, for example, to remove solids, particularly carbon black particles, from the heavy oil fraction 117, since a large amount of PAH compounds may also be separated with these solids.
When wiped film evaporation is used for the reduction or removal of PAH compounds, the process temperatures as described above for further fractionation may be employed.
In certain embodiments, the total PAH content in the disclosed PAH-reduced pyrolysis oil fraction is less than about 100ppm, less than about 50ppm, less than about 30ppm, less than about 20ppm, or less than about 10ppm by weight. In this pyrolysis oil fraction, the total PAH content is not specified, a simple matterThe method is to specify the total amount of a particular group of PAH compounds. For example, the disclosed PAH-reducing pyrolysis oil fraction may contain less than about 100ppm, less than about 50ppm, less than about 30ppm, less than about 20ppm, or less than about 10ppm by weight of benzo (a) pyrene, benzo (e) pyrene, benzo (a) anthracene, poly (A-co-p-phenylene vinylene),Total concentration of benzo (b) fluoranthene, benzo (j) fluoranthene, benzo (k) fluoranthene, and dibenzo (a, h) anthracene. Another approach is to specify the total amount of a particular PAH compound. For example, the disclosed PAH-reduced pyrolysis oil fraction may comprise less than about 10ppm, less than about 5ppm, less than about 3ppm, less than about 2ppm, or less than about 1ppm benzo (a) pyrene, by weight.
The end-use product 127 is desirably a translucent, low color (e.g., amber) liquid having a low solids content and especially a low carbon black content when evaluated at room temperature. In certain embodiments, the carbon black content in such end use products is less than about 5 wt.%, less than about 2 wt.%, less than about 1 wt.%, less than about 0.5 wt.%, or less than about 0.1 wt.%. The end use product 127 may, for example, have an open cup flash point, expressed as a flash point value, of at least 50 ℃, at least 60 ℃, at least 70 ℃, at least 80 ℃, at least 90 ℃ or at least 100 ℃.
The disclosed PAH-reducing pyrolysis oil fraction may be added to the asphalt binder in various amounts. The desired level of addition will typically be selected based in part on the effect such oil addition may have on the properties and intended end use of the asphalt binder so modified. For example, for asphalt compositions used in paving applications, the addition of a pyrolysis oil fraction that reduces PAH increases the penetration value of the asphalt binder, decreases the softening point of the binder, and alters pavement aging characteristics including pavement grade (e.g., Superpave PG value), aging sensitivity, and other performance indicators. Similar considerations will apply to other end uses, such as roofing materials and waterproofing membranes. For example, the disclosed PAH-reduced pyrolysis oil fractions may be used as viscosity modifiers in the production of a specification grade asphalt paving binder; used as asphalt regenerant for repairing or restoring existing pavement; aromatic compatibilizers for use as binders in polymer-modified asphalt paving and roofing materials; used as softening oil in the preparation of asphalt emulsion-based binders; as viscosity modifiers in the production of shingles, roll-up roofing materials, and other roofing materials; and as a plasticizer in the production of waterproofing membranes. For each of these applications, the amount of pyrolysis oil desired may vary based on a variety of considerations. However, as a general guideline, the level of the PAH-reducing pyrolysis oil fraction added to the asphalt binder may be at least about 0.5 wt%, at least about 1 wt%, at least about 2 wt%, at least about 3 wt%, at least about 4 wt%, or at least about 5 wt%, and up to about 30 wt%, up to about 25 wt%, up to about 20 wt%, up to about 15 wt%, up to about 13 wt%, or up to about 10 wt%, based on the total weight of the oil and binder.
A variety of asphalt binders can be modified using the disclosed methods. Exemplary bitumens include oxidized or air blown bitumens, non-oxidized bitumens, and mixtures thereof. Bitumen blowing (also known as oxidation or air rectification) can be used, for example, to produce oxidized or air blown bitumen of a desired consistency from a softer bitumen than the final bitumen product produced by the blowing process. The ideal result of the blowing process is an increase in softening point and a decrease in penetration value compared to the starting base bitumen. Typically, the blowing process involves heating the base asphalt to a temperature of about 232 ℃ (450 ° f) to 260 ℃ (500 ° f) and then blowing air into the hot asphalt for a period of time necessary to achieve the desired properties. The blowing process is a temperature-time dependent process in which the temperature and time are inversely proportional. Thus, at higher temperatures, the blowing time is generally less than the time required to achieve the same performance at lower temperatures. Generally, the exchange surface or contact surface between the hot bitumen and the air forced into it is also a factor in determining the length of the blowing process and the amount of air required.
Exemplary bitumens also include, but are not limited to, bitumens produced from atmospheric distillation, vacuum distillation, solvent extraction, or a combination of these methods. Other exemplary bitumens include naturally occurring bitumens, such as rock bitumens, asphaltenes, and the like.
In one embodiment, the disclosed pyrolysis oil fraction is combined with (e.g., injected into) a lower temperature molten asphalt binder such that the asphalt binder acts as a quencher for the pyrolysis oil fraction. The pyrolysis oil fraction may be, for example, within or near the distillation temperature range used for fractionation, and the asphalt binder may be at or slightly above its melting temperature. In some embodiments, the reduced PAH pyrolysis oil fraction is at least 25 ℃, at least 50 ℃, or at least 75 ℃ hotter than the molten asphalt binder prior to combining the reduced PAH pyrolysis oil fraction and the binder.
In one embodiment, the disclosed pyrolysis oil fraction is combined with a suitable solvent (e.g., petroleum distillate) prior to combination with the asphalt binder. Depending in part on the type and amount of solvent used, the resulting mixture may be used, for example, to prepare asphalt reducing, asphalt repair compounds, asphalt surface treatments, and other asphalt-containing compositions.
Preferred polymers are familiar to those of ordinary skill in the art and include elastomers (rubber or elastomer) such as styrene-butadiene rubber (SBR) and styrene-butadiene-styrene (SBS) and plastomers (plastics) such as polyethylene (e.g., low density polyethylene or "L DPE"), polypropylene (e.g., atactic polypropylene), and Ethylene Vinyl Acetate (EVA). depending on the desired properties, the polymer may, for example, comprise from about 0.5 to 30% by weight of the asphalt binder.
In another embodiment, the disclosed modified asphalt composition is used to prepare an asphalt emulsion. Those of ordinary skill in the art will be familiar with Emulsion manufacturing techniques, which are described, for example, in transport Research circulation E-C102(Asphal Emulsion Technology (2006)).
The disclosed invention is further illustrated in the following non-limiting examples. Performance grading via AASHTO M320 by using dynamic shear rheology and bending beam rheology can be used to demonstrate the effectiveness of the modifier in asphalt binder modification. The specific grade of asphalt and the type and amount of modifier used in the asphalt will affect the reported values. The reported values are intended to show the effect of the modifier, rather than the ability to reach a particular grade. For simplicity, the compositions were first prepared without reducing or removing PAH compounds from the pyrolysis oil samples.