A process for producing mesophase pitch includes charging a mixture of a carrier gas and a hydrocarbon feed including isotropic pitch to a reactor operating at thermal operating conditions sufficient to induce conversion of at least one chosen from the hydrocarbon feed and the isotropic pitch to mesophase pitch such that the mixture of the hydrocarbon feed and the carrier gas establishes a stratified flow regime having a vapor phase and a liquid phase in the reactor. The process also includes maintaining thermal operating conditions in the reactor while the mixture of the hydrocarbon feed and the carrier gas is flowing in the stratified flow regime in the reactor such that conversion of the at least one chosen from the hydrocarbon feed and the isotropic pitch to mesophase pitch is induced in the liquid phase. The process further includes discharging an effluent including mesophase pitch from the reactor.
A process for producing mesophase pitch includes charging a mixture of a carrier gas and a hydrocarbon feed including isotropic pitch to a reactor operating at thermal operating conditions sufficient to induce conversion of at least one chosen from the hydrocarbon feed and the isotropic pitch to mesophase pitch such that the mixture of the hydrocarbon feed and the carrier gas establishes a stratified flow regime having a vapor phase and a liquid phase in the reactor. The process also includes maintaining thermal operating conditions in the reactor while the mixture of the hydrocarbon feed and the carrier gas is flowing in the stratified flow regime in the reactor such that conversion of the at least one chosen from the hydrocarbon feed and the isotropic pitch to mesophase pitch is induced in the liquid phase. The process further includes discharging an effluent including mesophase pitch from the reactor.
A process for increasing a softening point of isotropic pitch includes providing a hydrocarbon feed including isotropic pitch having a first softening point and mixing the hydrocarbon feed with a carrier gas such that a mixture of the hydrocarbon feed and the carrier gas establishes at least one chosen from an annular-mist flow regime and a mist flow regime. The annular-mist flow regime includes a liquid film layer and a dispersion of entrained droplets, and the mist flow regime includes a dispersion of entrained droplets. The mixture of the hydrocarbon feed and the carrier gas approaches a vapor-liquid equilibrium. The process also includes discharging an effluent of the mixture into a separation vessel and separating a vapor phase and a liquid phase in the separation vessel. The liquid phase includes isotropic pitch having a second softening point greater than the first softening point.
A process for increasing a softening point of isotropic pitch includes providing a hydrocarbon feed including isotropic pitch having a first softening point and mixing the hydrocarbon feed with a carrier gas such that a mixture of the hydrocarbon feed and the carrier gas establishes at least one chosen from an annular-mist flow regime and a mist flow regime. The annular-mist flow regime includes a liquid film layer and a dispersion of entrained droplets, and the mist flow regime includes a dispersion of entrained droplets. The mixture of the hydrocarbon feed and the carrier gas approaches a vapor-liquid equilibrium. The process also includes discharging an effluent of the mixture into a separation vessel and separating a vapor phase and a liquid phase in the separation vessel. The liquid phase includes isotropic pitch having a second softening point greater than the first softening point.
A process for producing isotropic and mesophase pitch with reduced solids contamination from aromatic liquids contaminated with solids, such as catalyst fines or semi-coke. Contaminated feed is charged through one or more pitch forming reactors which discharge a pitch rich liquid and a vapor phase with reduced solids contamination. The vapor phase is cooled, condensed and may be charged continuously to another pitch forming reactor in parallel or used intermittently as a total or partial replacement for solids contaminated feed.
A process for making mesophase and/or isotropic pitch. An aromatic rich liquid is charged at high temperature and pressure to a first thermal polymerization reactor to produce an effluent stream which is flashed to remove unconverted or partially converted feed as a vapor yielding a liquid phase enriched in isotropic pitch. The enriched isotropic pitch liquid is charged to a second thermal reactor and reactor effluent flashed to produce mesophase pitch and a vapor phase. The vapor phases from both flashing steps are condensed and combined for recycle of a liquid aromatic rich stream to the first reactor. Flashing from the first reactor cools the liquid phase which is enriched in isotropic pitch. This enriched stream is mixed with a superheated fluid, preferably steam, upstream of the second reactor.
Producing mesophase pitch from liquid hydrocarbon feed comprising multi-ring aromatic compounds. In a first stage reactor feed is converted to isotropic pitch product contaminated with mesophase pitch. Contaminated isotropic pitch is charged to a second stage reactor where mesophase formation by self-assembly into spherical crystal clusters produces a mesophase pitch product. Water or steam added to the first stage reactor increases conversion of aromatic liquid feed, increases mesophase contamination of isotropic pitch product and reduces coke formation in the isotropic pitch reactor.
A process for making mesophase and/or isotropic pitch. An aromatic rich liquid is charged at high temperature and pressure to a first thermal polymerization reactor to produce an isotropic pitch rich liquid which is flashed. Residual liquid is charged to a second thermal reactor to produce mesophase pitch. The reactors can be either tubular reactors or CSTRs.
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.
brevets
