WO2021211789A1

WO2021211789A1 - Isotropic pitch and methods of making same

Info

Publication number: WO2021211789A1
Application number: PCT/US2021/027401
Authority: WO
Inventors: Stephen H. Brown; David C. Boyer; Donald P. Malone; George Alan Vaughan; Teng Xu; Jihad Dakka
Original assignee: Exxonmobil Research And Engineering Company; Advanced Carbon Products Llc
Priority date: 2020-04-17
Filing date: 2021-04-15
Publication date: 2021-10-21

Abstract

An isotropic pitch having (a) a coking value of 55 wt% to 65 wt% and a softening point of 50°C to 125°C; (b) the coking value of 65 wt% to 75 wt% and the softening point of 125°C to 175°C; or (c) the coking value of 70 wt% to 80 wt% and the softening point of 175°C to 200°C may be produced by a method comprising: distilling or thermally processing a feedstock having a T10 of 900°F (482°C) or greater and a T50 of 1000°F (538°C) or greater. In an embodiment a vacuum resid of hydrotreated steam cracker tar was used as feedstock. The hydrotreated steam cracker tar vacuum resid had the following properties: a carbon content of 92.3 wt%, hydrogen content of 7.55 wt%, a sulfur content of 0.5 wt%, a nitrogen content of 0.1 wt%, a T10 of 995°F (535°C), a T50 of 1157°F (625°C), a T90 of 1350°F (732°C), an MCRT of 39 wt%, and a softening point of 165°C.

Description

ISOTROPIC PITCH AND METHODS OF MAKING SAME

BACKGROUND

[0001] The present disclosure relates isotropic pitch and methods of producing isotropic pitch.

[0002] As used herein, the term “isotropic pitch” refers to pitch suitable for use as a feedstock for producing mesophase pitch.

[0003] As used herein, the term “mesophase pitch” refers to pitch that is a structurally ordered optically anisotropic liquid crystal.

[0004] Major markets for isotropic pitch include, but are not limited to, binder pitch for aluminum production anodes, aluminum production cathodes, impregnation pitch for steel electric arc furnace (EAF) electrodes, isotropic pitch carbon fiber, refractories, carbon/carbon, graphite, and graphite parts. When parts are manufactured from isotropic pitch, the coking value fraction of the pitch refers to the carbon content that will stay with the part while the rest is typically vaporized in the pyrolysis process. High coking value pitch enables parts producers to use less isotropic pitch to make the finished part and also to produce parts with higher density from a given fraction of isotropic pitch.

[0005] Softening point is another important characteristic of a pitch as it relates to the processability of the pitch. Pitches with lower softening points are more easily processed in manufacturing parts. However, as coking value increases, so does softening point.

[0006] A method for increasing coking value while maintaining a processible softening point is a wiped film evaporator (WFE), which is an energy-intensive and expensive technique, to achieve a high coking value followed by dilution with expensive solvents to achieve a suitable softening point. Implementation of this approach is expensive and uneconomic. Accordingly, economical methods for increasing coking value while maintaining a processible softening point would be of value to manufacturers.

SUMMARY OF THE INVENTION

[0007] The present disclosure relates to pitches with higher coking values and processible softening points and methods of producing such pitches.

[0008] The present disclosure includes a method comprising: distilling (or thermally processing) a feedstock having a T10 of 900°F (482°C) or greater and aT50 of 1000°F (538°C) or greater to produce an isotropic pitch. The present disclosure also includes the composition of the isotropic pitch produced by the foregoing method. The present disclosure also includes an electrode produced from the foregoing isotropic pitch. [0009] The present disclosure also includes an isotropic pitch having (a) a coking value of 55 wt% to 65 wt% and a softening point of 50°C to 125°C; (b) the coking value of 65 wt% to 75 wt% and the softening point of 125°C to 175°C; or (c) the coking value of 70 wt% to 80 wt% and the softening point of 175°C to 200°C. The pitch may have a mesophase content of less than 5 wt%, or less than 1 wt%, or less than 0.1 wt%. The present disclosure also includes an electrode produced from the foregoing isotropic pitch.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following figures are included to illustrate certain aspects of the embodiments, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure.

[0011] FIG. 1 is a nonlimiting example of a coil visbreaker system.

[0012] FIG. 2 is a coking value as a function of softening point plot of the various isotropic pitches produced from heavy feedstocks described herein.

PET All ED DESCRIPTION

[0013] The present disclosure relates isotropic pitches with higher coking values and processible softening points and methods of producing such isotropic pitches. More specifically, the isotropic pitches of the present disclosure are produced using unconventionally heavy feedstocks (i.e., high molecular weight feedstocks).

[0014] The molecular weight of a feedstock can be characterized by the distillation temperatures of the feedstock where Tn is the temperature at which n wt% of the pitch has distilled where n is 1-100. For example, with n=10, T10 is the temperature at which 10 wt% of the feedstock has distilled. Determination of Tn values can be performed according to ASTM D2887-18.

[0015] Traditional feedstocks for producing isotropic pitch include main column bottoms (MCB), ethylene cracker bottoms (ECB), other highly aromatic oils, coal tar, and derivatives of petroleum and coal tar. Traditional feedstocks have a T10 of 600°F (316°C) to 850°F (454°C) andaT50 of 700°F (371°C)to 850°F (454°C). In contrast, the feedstocks of the present disclosure have a T10 of 900°F (482°C) or greater (e.g., 900°F (482°C) to 1050°F (566°C)) and a T50 of 1000°F (538°C) or greater (e.g., 1000°F (538°C) to 1250°F (677°C)).

[0016] The molecular weight of a feedstock can be characterized by the average carbon number of the hydrocarbons in the feedstock. The heavy feedstocks of the present disclosure have higher concentrations of polynuclear aromatic hydrocarbons (PNAs) and polycyclic aromatic hydrocarbons (PAHs), which when hydrotreated become partially hydrogenated PNAs and partially hydrogenated PAHs. These species contribute to the heavy feedstocks of the present disclosure being composed of hydrocarbons having an average carbon number of about 35 to about 45. In comparison, traditional feedstocks like vacuum resid from MCB are composed of hydrocarbons having an average carbon number of about 25 to about 35 as determined by mass spectroscopy.

[0017] Further, traditional feedstocks have a low hydrogen content (e.g., 5 wt% to 7.5 wt% hydrogen). The resultant pitches produced typically have a hydrogen content of about 5.5 wt% or less. Generally, increasing boiling point of a feedstock trends with a decreasing hydrogen content. However, the heavy feedstocks used to produce pitches described herein have a higher hydrogen content (e.g., 7.5 wt% to 9 wt%) as compared to traditional feedstocks with a comparable boiling point. Accordingly, one skilled in the art would expect the pitch produced from the heavy feedstocks described herein to have a higher hydrogen content than pitch produced from traditional feedstock. However, unexpectedly, the pitches described herein have a hydrogen content comparable to that of pitches produced from traditional feedstock despite the higher hydrogen content of the heavy feedstock described herein.

[0018] Without being limited by theory, it is believed that the higher molecular weight of the hydrocarbons in the heavy feedstocks of the present disclosure and the ability to reduce the hydrogen content to typical pitch levels advantageously lead to a higher coking value at constant softening point in the resultant isotropic pitches.

[0019] The heavy feedstocks of the present disclosure can be used to produce isotropic pitches with significantly higher coking values as compared to isotropic pitches from traditional feedstocks at a comparable softening point. That is, the isotropic pitches described herein are high coking value pitches that are more easily processed as compared to isotropic pitches from traditional feedstocks.

Feedstock

[0020] The heavy feedstock of the present disclosure may be characterized by distillation temperature. The heavy feedstocks of the present disclosure have a T10 of 900°F (482°C) or greater (e.g., 900°F (482°C)to 1050°F (566°C), or950°F (510°C) to 1025°F (552°C), or975°F (524°C) to 1010°F (543°C)) and a T50 of 1000°F (538°C) or greater (e.g., 1000°F (538°C) to 1250°F (677°C), or 1100°F (593°C) to 1200°F (649°C), or 1125°F (607°C) to 1175°F (635°C)). The feedstocks of the present disclosure have a T90 of 1250°F (652°C) or greater (e.g., 1250°F (652°C) to 1450°F (788°C), or 1300°F (704°C) to 1400°F (760°C), or 1325°F (718°C) to 1375°F (746°C)). [0021] The heavy feedstock of the present disclosure may be characterized by an average carbon number. The heavy feedstocks of the present disclosure may be composed of hydrocarbons having an average carbon number of 35 to 45 (e.g., 35 to 40, or 37 to 42, or 40 to 45).

[0022] The heavy feedstock of the present disclosure may be characterized by a micro carbon residue (MCR). MCR is determined by ASTM D4530-15. The heavy feedstocks of the present disclosure may have an MCR of 30 wt% or greater (e.g., 30 wt% to 45 wt%, or 35 wt% to 45 wt%, or 37 wt% to 42 wt%.

[0023] The heavy feedstock of the present disclosure may be characterized by a hydrogen content. The feedstocks of the present disclosure may have a hydrogen content of 7 wt% to 9 wt% (e.g., 7 wt% to 8 wt%, or 7.5 wt% to 9 wt%, or 8 wt% to 9 wt%).

[0024] The heavy feedstock of the present disclosure may be characterized by a cumulative concentration of PNAs and PAHs. The feedstocks of the present disclosure may have a cumulative concentration of partially hydrogenated PNAs and partially hydrogenated PAHs of 50 wt% or greater (e.g., 50 wt% to 90 wt%, 50 wt% to 59 wt%, or 50 wt% to 75 wt%, or 60 wt% to 90 wt%).

[0025] The feedstock may consist of a heavy feedstock described herein.

[0026] An example of heavy feedstock is a hydrotreated steam cracker tar vacuum resid, which is the vacuum resid from hydrotreating steam cracker tar. That is, methods of producing a heavy feedstock described herein may include hydrotreating a steam cracker tar vacuum distilling the hydrotreated steam cracker tar; and collecting the vacuum resid of the distillation as the heavy feedstock. Steam cracker tar and subsequent hydrotreating can be produced/performed by any suitable method including for example, as disclosed in US Pat. Nos. 8,105,479, which is incorporated herein by reference.

Isotropic Pitch and Methods of Production

[0027] Isotropic pitch of the present disclosure can be produced by distilling or thermally processing a feedstock comprising a heavy feedstock described herein. The distillation or thermal processes can be carried out in various process units such as a visbreaker units.

[0028] Visbreaker units are generally of two types, soaker or coil. The soaker type unit uses a heater ahead of a heat soak drum, which is a tank-like vessel fitted with internals to reduce back mixing and improve plug flow, in which the heated feed is held for a time sufficient to enable the desired degree of thermally -induced cracking to proceed. The coil visbreaker normally has a two-zone fired heater with the reaction zone formed by furnace coils through which the feed passes in plug flow. The soaker visbreaker operates at lower temperatures with longer residence times than the coil type visbreaker and, as a result, tends to have a lower energy requirement. The coil visbreaker, however, enables better control of the reaction conditions with varying feeds and can, moreover, be more easily decoked by steam-air decoking. In both cases, however, the cracking reactions are terminated by quenching and no resort is made to recycle. A coil unit typically operates at an outlet temperature of 700°F to 1100°F (371°C to 593°C), outlet pressure of 150 psig to 750psig, and a residence time in the coil of 1 minute to 20 minutes. A soaker unit typically operates at less harsh conditions with a furnace outlet temperature of 700°F to 900°F (371°C to 482°C), an outlet pressure or 45 psig to 150 psig, and a residence time 5 minutes to 10 minutes.

[0029] FIG. 1 is a nonlimiting example of a coil visbreaker system 100. The feedstock is introduced to a coil furnace 104 via line 102. The coil furnace 104 operates at a temperature and pressure sufficient to crack the feedstock. The cracked product is conveyed to a distillation column 108 via line 106 where the cracked product is distilled into desired cuts. In the illustrated example, the cuts include an overheads cut at line 110, a distillate cut at line 122, and a bottoms cut at line 124. The bottoms cut can be used as a quench by recycling it back to the cracked product line 106 via line 126. The quench assists with stopping the cracking reaction. The bottoms cut can be the isotropic pitch described herein or may be further processed (e.g., in another distillation column) to produce the isotropic pitch described herein. The overheads cut is conveyed via line 110 to a heat exchanger 112 and flash tank 114 to separate the overheads cut into a gas cut at line 116 and a naphtha cut at line 118. A portion of the product from the flash tank 114 may be recycled to the distillation column 108 via line 120. [0030] The coil visbreaker system 100 can include additional components line valves, compressors, pumps, sensors (e.g., temperature sensors and pressure sensors), and the like as needed for proper and safe operation of the coil visbreaker system 100.

[0031] FIG. 1 is a nonlimiting example of a coil visbreaker system 100. One skilled in the art will recognize other systems suitable for producing isotropic pitches described herein. [0032] The resultant isotropic pitch can be characterized by its coking value and softening point. As illustrated in the examples, the isotropic pitches of the present disclosure have a higher coking value for a similar softening point as compared to isotropic pitches produces with a traditional feedstock.

[0033] Softening point is determined by a ring and ball methods described in ASTM D36/D36M-14el.

[0034] Coking value can be determined by ASTM D4715 - 98(2017). [0035] The extent of distillation or thermal treatment of the feedstock comprising the heavy feedstock described herein is used to achieve a desired softening point. The corresponding coking value is a result of using the heavy feedstock. A first example of a resultant isotropic pitch can be characterized as having a coking value of 55 wt% to 65 wt% and a softening point of 50°C to 125°C. A second example of a resultant isotropic pitch can be characterized as having a coking value of 65 wt% to 75 wt% and a softening point of 125°C to 175°C. A third example of a resultant isotropic pitch can be characterized as having a coking value of 70 wt% to 80 wt% and a softening point of 175°C to 200°C.

[0036] The isotropic pitch of the present disclosure may have a mesophase content of less than 5 wt%, or less than 1 wt%, or less than 0.1 wt%.

[0037] When the isotropic pitch is used to produce anodes, cathodes, and other electrodes, there is a mesophase pitch content specification of less than 5 wt%. The mesophase pitch content is measured using polarized light microscopy. The pitches of the invention are able to meet this specification. Mesophase pitch is usually detectable in the products of the invention but at levels well below the 5 wt% specification. When the isotropic pitch is used as a feedstock for mesophase production or for other applications where mesophase content is unimportant, then it is not necessary to meet the 5 wt% specification.

Articles and Methods of Manufacturing

[0038] The isotropic pitch described herein produced from feedstocks comprising heavy feedstock described herein can be used to produce carbon fibers by known methods.

[0039] The isotropic pitch described herein produced from feedstocks comprising heavy feedstock described herein can also be used in the production of electrodes (e.g., EAF anodes, aluminum production anodes, aluminum production cathodes, graphite electrodes, and the like). Examples of electrode production methods are described in US Patent Nos. 4,086,156, 4,379,814, 4,729,689, 5,413,738, and 5,792,577, each of which is incorporated herein by reference. By way of nonlimiting example, to make electrodes, especially for aluminum production, the isotropic pitch binder can be mixed with coke, usually in a proportion 14 wt% to 17 wt% based on the weight of coke for a prebaked electrode and 26 wt% to 32 wt% based on the weight of coke for the Soderberg type electrode. The mixing usually occurs at a temperature of 150°C to 170°C. The prebaked electrodes formed after extrusion or pressing are baked at high temperature using special ovens.

[0040] The isotropic pitch described herein produced from feedstocks comprising heavy feedstock described herein can be used as a precursor to a mesophase pitch. Any known methods can be used to convert the isotropic pitch to mesophase pitch. For example, the isotropic pitch may be heated in a non-oxidizing environment under sufficient temperature and pressure to produce the mesophase pitch. Optionally, the method may further include foaming the mesophase pitch to produce a foamed mesophase pitch. Such methods generally include rapidly reducing the pressure while the mesophase pitch is at an elevated temperature (e.g., when cooling the mesophase pitch during production).

[0041] The mesophase pitch and/or the foamed mesophase pitch can be stabilized and graphitized by known methods to form graphite parts.

[0042] The isotropic pitch described herein produced from feedstocks comprising heavy feedstock described herein can also be used in construction products like binder used to produce carbon-carbon composites. For example, the isotropic pitch described herein can be applied to layers of carbon fiber fabric and then stamped into parts using a high temperature and high pressure isostatic press.

Example Embodiments

[0043] A first nonlimiting example embodiment of the present disclosure is a method comprising: distilling (or thermally processing) a feedstock having a T10 of 900°F (482°C) or greater and a T50 of 1000°F (538°C) or greater to produce an isotropic pitch.

[0044] The first nonlimiting example embodiment may include one or more of the following: Element 1 : wherein the isotropic pitch has a coking value of 55 wt% to 65 wt% and a softening point of 50°C to 125°C; Element 2: wherein the isotropic pitch has a coking value of 65 wt% to 75 wt% and a softening point of 125°C to 175°C; Element 3: wherein the isotropic pitch has a coking value of 70 wt% to 80 wt% and a softening point of 175°C to 200°C; Element 4: wherein the isotropic pitch has a mesophase content of less than 5 wt%, or less than 1 wt%, or less than 0.1 wt%; Element 5: wherein the feedstock is composed of hydrocarbons having an average carbon number of 35 to 45; Element 6: wherein the feedstock has a micro carbon residue (MCR) of 30 wt% or greater; Element 7 : wherein the feedstock has a hydrogen content of 7.5 wt% to 8 wt%; Element 8: wherein the feedstock comprises 50 wt% or greater cumulatively of partially hydrogenated polynuclear aromatic hydrocarbons and partially hydrogenated polycyclic aromatic hydrocarbons; Element 9: wherein the feedstock comprises a hydrotreated steam cracker tar vacuum resid; Element 10: wherein the distilling (or thermally processing) is performed in a coil visbreaker; Element 11: wherein the distilling (or thermally processing) is performed in a soaker-type visbreaker; Element 12: the method further comprising heat treating the isotropic pitch in a non-oxidizing environment to convert at least a portion of the isotropic pitch to mesophase pitch; Element 13: the method further comprising heat treating the isotropic pitch in a non-oxidizing environment to convert at least a portion of the isotropic pitch to mesophase pitch; and reducing the pressure while the mesophase pitch is at an elevated temperature to foam the mesophase pitch and produce a foamed mesophase pitch; Element 14: Element 13 and the method further comprising stabilizing and graphitizing the foamed mesophase pitch into a graphite foam part. Examples of combinations include, but are not limited to, one of Elements 1-3 in combination with Element 4; two or more of Elements 5-9 in combination; one or more of Elements 1-4 in combination with one or more of Elements 5-9; Element 10 or 1 lin combination with one or more of Elements 1-9; Element 12 or Element 13 (optionally with Element 14) in combination with Element 10 or 11 and optionally in further combination with one or more of Elements 1-9; and Element 12 or Element 13 (optionally with Element 14) in combination with one or more of Elements 1-9,

[0045] A second nonlimiting example embodiment is the isotropic pitch produced by a method according to the first nonlimiting example embodiment, which may include one or more of Elements 1-14.

[0046] A third nonlimiting example embodiment is an electrode produced from the isotropic pitch of the second nonlimiting example embodiment.

[0047] A fourth nonlimiting example embodiment is an isotropic pitch having (a) a coking value of 55 wt% to 65 wt% and a softening point of 50°C to 125°C; (b) the coking value of 65 wt% to 75 wt% and the softening point of 125°C to 175°C; or (c) the coking value of 70 wt% to 80 wt% and the softening point of 175°C to 200°C. The pitch may have a mesophase content of less than 5 wt%, or less than 1 wt%, or less than 0.1 wt%.

[0048] A fifth nonlimiting example is an electrode produced from the isotropic pitch of the fourth nonlimiting example embodiment.

[0049] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. [0050] One or more illustrative embodiments incorporating the invention embodiments disclosed herein are presented herein. Not all features of a physical implementation are described or shown in this application for the sake of clarity. It is understood that in the development of a physical embodiment incorporating the embodiments of the present invention, numerous implementation-specific decisions must be made to achieve the developer’s goals, such as compliance with system-related, business-related, government- related and other constraints, which vary by implementation and from time to time. While a developer’s efforts might be time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in the art and having benefit of this disclosure.

[0051] While compositions and methods are described herein in terms of “comprising” various components or steps, the compositions and methods can also “consist essentially of’ or “consist of’ the various components and steps.

[0052] To facilitate a better understanding of the embodiments of the present invention, the following examples of preferred or representative embodiments are given. In no way should the following examples be read to limit, or to define, the scope of the invention.

EXAMPLES

[0053] Comparative Example 1

[0054] A conventional petroleum pitch was produced using a starting material of a hydrotreated main column bottoms (MCB) feedstock having a density of 1.16 g/mL, a sulfur content of 0.15 wt%, a hydrogen content of 7.5 wt%, a T10 of 680°F (360°C), a T50 of 784°F (417°C), a T90 of 1007°F (542°C), 5 wt% boiling over 1050+°F (566+°C), a MCRT of 12 wt%, a viscosity at 80°C of 75 cP, and a viscosity at 105°C of 22 cP.

[0055] 300 g of hydrotreated MCB feedstock was charged to a 500 mL autoclave. The autoclave was heated to 425 °C and 1000 psig and held there for 4 hours before rapidly cooling to 300°C. The autoclave was emptied and the liquid contents were vacuum distilled until the remaining bottoms (first isotropic pitch product) had a softening point of 115°C and a coking value of 50 wt%. The yield of the first isotropic pitch product was 114 g, or 38 wt% of the hydrotreated MCB feedstock. The first isotropic pitch product was further vacuum distilled to the practical limit of the laboratory distillation equipment, which removes most of the material boiling below 850°C (454°C). The yield of second isotropic pitch product was 107 g, or 36% of the hydrotreated MCB feedstock, with a softening point of 130°C and a coking value of 54 wt%. The second isotropic pitch product was further distilled in a wiped film evaporator to produce 75 g of a third isotropic pitch product, or 25% of the hydrotreated MCB feedstock, with a softening point of 260°C, a coking value of 80 wt%, and a mesophase content of less than 0.1 wt%.

[0056] Inventive Example 1 [0057] An inventive petroleum pitch was produced using a starting material of a vacuum resid of hydrotreated steam cracker tar. The hydrotreated steam cracker tar vacuum resid had the following properties: a carbon content of 92.3 wt%, hydrogen content of 7.55 wt%, a sulfur content of 0.5 wt%, a nitrogen content of 0.1 wt%, a T10 of 995°F (535°C), a T50 of 1157°F (625°C), a T90 of 1350°F (732°C), an MCRT of 39 wt%, and a softening point of 165°C. It should be noted that the elemental contents described add up to more than 100%, which is due to detection limits, rounding, and other measurement-error from the elemental analysis.

[0058] 350 g of hydrotreated steam cracker tar vacuum resid was charged to a 500 mL autoclave. The autoclave was heated to 425°C and 1000 psig and held there for 8 hours before rapidly cooling to 300°C. The autoclave was emptied and the liquid contents were vacuum distilled to pull off all material boiling below 650°F (343 °C) to produce a first isotropic pitch product of 280 g, or 80% of the starting material. The first isotropic pitch product had a softening point of 61°C, a coking value of 55 wt%, and a mesophase content of less than 0.1 wt%.

[0059] Distillation of the first isotropic pitch product was then continued to pull off light hydrocarbons to the maximum practical limit by vacuum distillation equipment, which removes most of the material boiling below 850°F (454°C), to produce a second isotropic pitch product of 245 g, or 70% of the starting material. The second isotropic pitch product had a softening point of 175°C, a coking value of 72 wt%, and a mesophase content of less than 0.1 wt%.

[0060] Inventive Example 2

[0061] An inventive petroleum pitch was produced using a starting material of a vacuum resid of hydrotreated steam cracker tar. The hydrotreated steam cracker tar vacuum resid had the following properties: a carbon content of 92.3 wt%, hydrogen content of 7.55 wt%, a sulfur content of 0.5 wt%, a nitrogen content of 0.1 wt%, a T10 of 995°F (535°C), a T50 of 1157°F (625°C), a T90 of 1350°F (732°C), an MCRT of 39 wt%, and a softening point of 165°C. [0062] Additional Examples

[0063] Experiments similar to the foregoing were performed using either hydrotreated MCBs (conventional feedstock) or hydrotreated steam cracker tar vacuum resid. FIG. 2 is a coking value as a function of softening point plot of the various isotropic pitch products therefrom. The plot illustrates that using hydrotreated steam cracker tar vacuum resid as a feedstock provide isotropic pitches with a higher coking value for a similar softening point as compared to the conventional feedstock and pitches with a lower softening point for a similar coking value as compared to conventional feedstock. [0064] Hypothetical Example 1

[0065] 100 g of the second isotropic pitch product of Inventive Example 1 is placed in an oven at 430°C under 3,000 psig of nitrogen for 15 minutes. During this time, the isotropic pitch is converted to mostly mesophase pitch. The oven is then cooled over the course of 15 minutes to 400°C, which is the softening point of the mesophase pitch. The oven is then depressured to 1 atm pressure causing the pitch to puff up into a foam. Cooling the foam to 200°C set the mesophase pitch foam. The foamed mesophase pitch is ready to be stabilized and graphitized for conversion into a graphite foam part.

[0066] Therefore, the present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the present invention. The invention illustratively disclosed herein suitably may be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of’ or “consist of’ the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces.

Claims

CLAIMS The invention claimed is:

1. A method comprising: distilling or thermally processing a feedstock having a T10 of 900°F (482°C) or greater and a T50 of 1000°F (538°C) or greater to produce an isotropic pitch.

2. The method of claim 1, wherein the isotropic pitch has a coking value of 55 wt% to 65 wt% and a softening point of 50°C to 125°C.

3. The method of claim 1, wherein the isotropic pitch has a coking value of 65 wt% to 75 wt% and a softening point of 125°C to 175°C.

4. The method of claim 1, wherein the isotropic pitch has a coking value of 70 wt% to 80 wt% and a softening point of 175°C to 200°C.

5. The method of any preceding claim, wherein the isotropic pitch has a mesophase content of less than 5 wt%.

6. The method of any preceding claim, wherein the feedstock is composed of hydrocarbons having an average carbon number of 35 to 45.

7. The method of any preceding claim, wherein the feedstock has a micro carbon residue (MCR) of 30 wt% or greater.

8. The method of any preceding claim, wherein the feedstock has a hydrogen content of 7.5 wt% to 8 wt%.

9. The method of any preceding claim, wherein the feedstock comprises 50 wt% or greater cumulatively of partially hydrogenated polynuclear aromatic hydrocarbons and partially hydrogenated polycyclic aromatic hydrocarbons.

10. The method of any preceding claim, wherein the feedstock comprises a hydrotreated steam cracker tar vacuum resid.

11. The method of any preceding claim, wherein the distilling or thermally processing is performed in a coil visbreaker.

12. The method of any preceding claim, wherein the distilling or thermally processing is performed in a soaker-type visbreaker.

13. The isotropic pitch produced according to any preceding claim.

14. An electrode produced from the isotropic pitch of claim 13.

15. The method of one of claims 1-12 further comprising: heat treating the isotropic pitch in a non-oxidizing environment to convert at least a portion of the isotropic pitch to mesophase pitch.

16. The method of one of claims 1-12 further comprising: heat treating the isotropic pitch in a non-oxidizing environment to convert at least a portion of the isotropic pitch to mesophase pitch; and reducing the pressure while the mesophase pitch is at an elevated temperature to foam the mesophase pitch and produce a foamed mesophase pitch.

17. The method of claim 16 further comprising: stabilizing and graphitizing the foamed mesophase pitch into a graphite foam part.

18. An isotropic pitch having (a) a coking value of 55 wt% to 65 wt% and a softening point of 50°C to 125°C; (b) the coking value of 65 wt% to 75 wt% and the softening point of 125°C to 175°C; or (c) the coking value of 70 wt% to 80 wt% and the softening point of 175°C to 200°C.

19. An electrode produced from the isotropic pitch of claim 18.