US-20260125333-A1 - POLYCYCLIC AROMATIC MOLECULES, PITCH AND GRAPHITE, HAVING LOW IMPURITIES AND LARGE CRYSTALLINE STRUCTURE, AND PRODUCTS MADE THEREFROM

Abstract

High-purity polycyclic aromatic hydrocarbons (PAHs) and the byproducts thereof, and methods for producing such products are disclosed. The PAHs may comprise an aromaticity index of about 0.65 to about 0.80. The PAHs may have quinoline insolubles and sulfur impurities of less than about 0.1 wt. % each. A tar or pitch comprising the high-purity PAHs and a method of producing such tar or pitch are disclosed. A synthetic graphite comprising high-purity PAHs is also disclosed. A method of making carbon pellets from high-purity PAHs is also disclosed.

Inventors

• George L. Skoptsov
• Aayush Mantri
• Vignesh Viswanathan

Assignees

• H Quest Vanguard, Inc.

Dates

Publication Date

20260507

Application Date

20251219

Claims (1)

1. 1 . High-purity polycyclic aromatic hydrocarbons comprising: an aromaticity index of about 0.65 to about 0.80; less than about 0.1 wt. % quinoline insolubles; and less than about 0.1 wt. % sulfur.

Description

RELATED APPLICATIONS AND CLAIM OF PRIORITY This patent document is a continuation of U.S. patent application Ser. No. 18/468,423, filed Sep. 15, 2023, which claims priority to U.S. provisional patent application No. 63/375,981, filed Sep. 16, 2022, the disclosures of which are both fully incorporated into this document by reference. TECHNICAL FIELD This disclosure is related to processing of a feed stream and the production of high-purity and high-aromatic polycyclic aromatic hydrocarbons, tar or pitch, and graphite made therefrom. BACKGROUND Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals that occur naturally in coal, crude oil, and gasoline. They result from burning coal, oil, gas, wood, garbage, and tobacco. PAHs encompass many compounds composed primarily of carbon and hydrogen (CXHY), where carbon is mostly arranged in aromatic ring configuration with sp2 hybridization. Examples of PAHs are naphthalene, anthracene, phenanthrene, acenaphthylene, acenaphthene, fluorene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene. PAH consist of fused rings connected to each other, ranging from the monocyclic molecule of benzene (molecular weight=78) up to nine-ringed structures (MW up to 478). PAHs can also contain small fractions of oxygen or nitrogen or other atoms. They are mostly used as intermediaries in pharmaceuticals, agricultural products, photographic products, thermosetting plastics, lubricating materials, and other chemical industries. Coal tar and pitch are known to have high concentrations of PAHs, and PAHs can thus be used as an element to create tar and pitch. Tar and pitch have a large number of solid carbon particles. When the tar or pitch is dissolved in quinoline, the solid carbon particles typically do not dissolve. Thus, such particles are sometimes referred to as “quinoline insolubles.” The type and amount of quinoline insolubles in tar or pitch can affect the product's quality or suitability for specific purposes. For instance, in the context of making carbon electrodes, some contents of these quinoline insoluble (QI) particles may be desired. Large amounts of quinoline insolubles, or particles of relatively large size, can cause issues such as increased abrasion and clogging of equipment. However, if the amount of quinoline insoluble is too small, the electrical properties and binding capabilities of the product may be too low. Thus, it is desirable to be able to control the amount of quinoline insoluble that coal tar and pitch contain. However, when pitch is used specifically as a feedstock for needle coke, carbon fiber, or synthetic graphite, QI particles interfere with the graphitization process and their presence significantly degrades the product quality. QI particles are often formed during formation of the tar or pitch, as portions of it carbonize into particles, such as in the coking process. Removal or separation of the naturally present QI particles from tar or pitch is difficult and costly due to high viscosity of the latter. SUMMARY High-purity polycyclic aromatic hydrocarbons are disclosed herein comprising less than about 0.1 wt. % quinoline insolubles and less than about 0.1 wt. % sulfur. The PAHs may exhibit an aromaticity index of about 0.65 to about 0.80, or about 0.10 to about 0.30, depending on the final product and the feedstock used. In some embodiments, the high-purity polycyclic aromatic hydrocarbons comprise about 0.05 wt. % to about 0.00 wt. % quinoline insolubles, or about 0.05 wt. % to about 0.00 wt. % sulfur. In various embodiments, such as embodiments in which the PAHs are used to produce methane tar or methane pitch, the high-purity polycyclic aromatic hydrocarbons may have an aromaticity index of about 0.65 to about 0.80, about 0.65 to about 0.75, about 0.70 to about 0.74, or about 0.70 to about 0.77. In other embodiments, the high-purity polycyclic aromatic hydrocarbons may have an aromaticity index of about 0.10 to about 0.30, or about 0.20 to about 0.25. The high-purity polycyclic aromatic hydrocarbons may contain less than about 5% by volume of single-ring phenols such as resorcinol, 2-methylphenol, 3-methylphenol, or 4-methylphenol, and/or over about 80% by volume of a mixture of 2-ring, 3-ring and 4 or more-ring aromatic hydrocarbons. The high-purity polycyclic aromatic hydrocarbons may be derived from decomposition of methane, natural gas, or other hydrocarbon feedstock, and/or co-generated with solid carbon in which the solid carbon optionally has a surface area from about 7 m2/g to about 520 m2/g. Tars and pitches are disclosed herein comprising the high-purity polycyclic aromatic hydrocarbons of any of the embodiments described above. A synthetic graphite is disclosed herein comprising high-purity polycyclic aromatic hydrocarbons of any of the embodiments described above. The graphite may contain crystals of carbonized and graphitized high-purity polycyclic aromatic hydrocarbons having a lateral dimension (La)