615
Hydrocracking
designed to maintain a mixed three-phase slurry of feedstock, fine powder catalyst, and hydrogen, and to promote effective contact.
In the process, a slurry consisting of heavy oil feedstock and fine powder catalyst is preheated
in a furnace and fed into the reactor vessel. Hydrogen is introduced from the bottom of the reactor
and flows upward through the reaction mixture, maintaining the catalyst suspension in the reaction mixture. Cracking, desulfurization, and demetallization reactions are taken place via thermal
and catalytic reactions. In the upper section of the reactor, vapor is disengaged from the slurry,
and hydrogen and other gases are removed in a high-pressure separator. The liquid condensed
from the overhead vapor is distilled and then flows out to the secondary treatment facilities.
From the lower section of the reactor, bottom slurry oil (SLO) that contains catalyst,
uncracked residuum and a small amount of vacuum gas oil fraction are withdrawn. Vacuum gas
oil is recovered in the slurry separation section, and the remaining catalyst and coke are fed to
the regenerator.
Product distribution focuses on middle distillates with the process focused as a residuum processing unit and inserted into a refinery just downstream from the vacuum distillation unit.
22.3.15 rCd unIBon ProCess
The RCD Unibon process (BOC process) is a process to upgrade vacuum residua (RAROP, 1991,
p. 67; Thompson, 1997). There are several possible flow scheme variations involving for the process. It can operate as an independent unit or be used in conjunction with a thermal conversion
unit. In this configuration, hydrogen and a vacuum residuum are introduced separately to the
heater, and mixed at the entrance to the reactor. To avoid thermal reactions and premature coking
of the catalyst, temperatures are carefully controlled and conversion is limited to approximately
70% of the total projected conversion. The removal of sulfur, heptane-insoluble materials, and
metals is accomplished in the reactor. The effluent from the reactor is directed to the hot separator. The overhead vapor phase is cooled, condensed, and the separated hydrogen is recycled to
the reactor.
Liquid product goes to the thermal conversion heater where the remaining conversion of nonvolatile materials occurs. The heater effluent is flashed, and the overhead vapors are cooled, condensed, and routed to the cold flash drum. The bottoms liquid stream then goes to the vacuum
column where the gas oils are recovered for further processing, and the residuals are blended into
the heavy fuel oil pool.
22.3.16 resIdFInIng ProCess
Residfining is a catalytic fixed-bed process for the desulfurization and demetallization of atmospheric and vacuum residua (RAROP, 1991, p. 69). The process can also be used to pretreat residua
to suitably low contaminant levels prior to catalytic cracking.
In the process, liquid feedstock to the unit is filtered, pumped to pressure, preheated, and combined with treat gas prior to entering the reactors. A small guard reactor would typically be employed
to prevent plugging/fouling of the main reactors. Provisions are employed to periodically remove
the guard while keeping the main reactors online. The temperature rise associated with the exothermic reactions is controlled utilizing either a gas- or liquid-quench. A train of separators is employed
to separate the gas and liquid products. The recycle gas is scrubbed to remove ammonia and hydrogen sulfide. It is then combined with fresh makeup hydrogen before being reheated and recombined
with fresh feed. The liquid product is sent to a fractionator where the product is fractionated.
Residfining is an option that can be used to reduce the sulfur, to reduce metals and coke-forming
precursors, and/or to accomplish some conversion to low-boiling products as a feed pre-treat step
ahead of a fluid catalytic cracking unit. There is also a hydrocracking option where substantial conversion of the resid occurs.
Hydrocracking
designed to maintain a mixed three-phase slurry of feedstock, fine powder catalyst, and hydrogen, and to promote effective contact.
In the process, a slurry consisting of heavy oil feedstock and fine powder catalyst is preheated
in a furnace and fed into the reactor vessel. Hydrogen is introduced from the bottom of the reactor
and flows upward through the reaction mixture, maintaining the catalyst suspension in the reaction mixture. Cracking, desulfurization, and demetallization reactions are taken place via thermal
and catalytic reactions. In the upper section of the reactor, vapor is disengaged from the slurry,
and hydrogen and other gases are removed in a high-pressure separator. The liquid condensed
from the overhead vapor is distilled and then flows out to the secondary treatment facilities.
From the lower section of the reactor, bottom slurry oil (SLO) that contains catalyst,
uncracked residuum and a small amount of vacuum gas oil fraction are withdrawn. Vacuum gas
oil is recovered in the slurry separation section, and the remaining catalyst and coke are fed to
the regenerator.
Product distribution focuses on middle distillates with the process focused as a residuum processing unit and inserted into a refinery just downstream from the vacuum distillation unit.
22.3.15 rCd unIBon ProCess
The RCD Unibon process (BOC process) is a process to upgrade vacuum residua (RAROP, 1991,
p. 67; Thompson, 1997). There are several possible flow scheme variations involving for the process. It can operate as an independent unit or be used in conjunction with a thermal conversion
unit. In this configuration, hydrogen and a vacuum residuum are introduced separately to the
heater, and mixed at the entrance to the reactor. To avoid thermal reactions and premature coking
of the catalyst, temperatures are carefully controlled and conversion is limited to approximately
70% of the total projected conversion. The removal of sulfur, heptane-insoluble materials, and
metals is accomplished in the reactor. The effluent from the reactor is directed to the hot separator. The overhead vapor phase is cooled, condensed, and the separated hydrogen is recycled to
the reactor.
Liquid product goes to the thermal conversion heater where the remaining conversion of nonvolatile materials occurs. The heater effluent is flashed, and the overhead vapors are cooled, condensed, and routed to the cold flash drum. The bottoms liquid stream then goes to the vacuum
column where the gas oils are recovered for further processing, and the residuals are blended into
the heavy fuel oil pool.
22.3.16 resIdFInIng ProCess
Residfining is a catalytic fixed-bed process for the desulfurization and demetallization of atmospheric and vacuum residua (RAROP, 1991, p. 69). The process can also be used to pretreat residua
to suitably low contaminant levels prior to catalytic cracking.
In the process, liquid feedstock to the unit is filtered, pumped to pressure, preheated, and combined with treat gas prior to entering the reactors. A small guard reactor would typically be employed
to prevent plugging/fouling of the main reactors. Provisions are employed to periodically remove
the guard while keeping the main reactors online. The temperature rise associated with the exothermic reactions is controlled utilizing either a gas- or liquid-quench. A train of separators is employed
to separate the gas and liquid products. The recycle gas is scrubbed to remove ammonia and hydrogen sulfide. It is then combined with fresh makeup hydrogen before being reheated and recombined
with fresh feed. The liquid product is sent to a fractionator where the product is fractionated.
Residfining is an option that can be used to reduce the sulfur, to reduce metals and coke-forming
precursors, and/or to accomplish some conversion to low-boiling products as a feed pre-treat step
ahead of a fluid catalytic cracking unit. There is also a hydrocracking option where substantial conversion of the resid occurs.