US 9,376,626 B1 · Turbulent mesophase pitch process and products

Abstract

A process for producing mesophase pitch using a long tube reactor is disclosed. An aromatic rich feed, preferably a petroleum pitch having a softening point above 100° C., is preheated to a temperature above its softening point and mixed with a vapor, preferably steam, in a long tubular reactor under intense mixing conditions, preferably fully developed turbulent flow such as mist annular flow, with a residence time at least an order of magnitude less than prior art processes and preferably less than 10 seconds. Preferably the reactor is heated by electric resistance or induction heating or by immersion in a heated fluid or in a fired heater. Mesophase pitch with a high coking value and a surprisingly low quinolone insoluble content is produced. The byproducts of thermal polymerization and thermal dealkylation have less than 50% as much olefin and diene content as compared to similar byproducts from prior art processes.

Claims17

Dependent claims

A process for producing mesophase pitch from an aromatic liquid feed comprising

a.) Charging an aromatic liquid feed and a vapor source to a reactor operating at thermal polymerization conditions,
b.) Maintaining thermal polymerization conditions in said reactor including turbulent flow and a temperature sufficient to induce thermal polymerization of said feed into mesophase pitch and high enough to produce coke,
c.) Discharging a mesophase pitch containing product stream from said reactor after a residence time of less than one minute and long enough to convert a majority by weight of said feed to mesophase pitch and short enough to prevent or reduce formation of coke and wherein at least an order of magnitude more mesophase pitch is produced than coke.

In a continuous process for converting isotropic pitch to mesophase pitch by charging a feed isotropic pitch, having a boiling range and wherein at least a majority of said feed is a nondistillable residue liquid, to an inlet of a tubular reactor having tube walls and operating at thermal polymerization conditions including a pressure and a temperature and for a time sufficiently high to thermally polymerize at least a portion of said isotropic pitch feed to mesophase pitch and to thermally crack and dealkylate at least a portion of said isotropic pitch feed to vaporizable hydrocarbons having a boiling point below that of said isotropic pitch feed and coke as an undesired byproduct which deposits within said tubular reactor, the improvement comprising adding water or steam to said tubular reactor at a weight ratio of water or steam to isotropic pitch feed of 0.5:1 to 2:1, maintaining said pressure low enough and said temperature high enough in said tubular reactor to maintain at least a majority, by volume, of material in said tubular reactor in vapor phase, maintaining residence time of less than 10 seconds and temperature in said tubular reactor sufficient to convert at least ⅓, by weight, of said isotropic pitch feed to mesophase pitch and vaporizable materials having a boiling range below said isotropic pitch feed, and wherein said isotropic pitch feed rate, said water or steam addition, and velocity in said tubular reactor are sufficient to reduce coke deposition within the walls of said tubular reactor to less than 0.001″/hr.

Dependencies are inferred from the claim text.

Turbulent mesophase pitch process and products

Life of this patent

Turbulent mesophase pitch process and products

Life of this patent

Abstract

Claims17