A process for extracting isoprene from a pyrolysis gas mixture or a C5 fraction wherein isoprene is purified by plural extractive distillations in the presence of a polar solvent and cyclopentadiene is effectively removed and recycled as a feedstock without being converted into its dimer, dicyclopentadiene. The isoprene recovered from the process described is more than 99.5% pure.

Processes and systems for controlling operation of a commercial refinery distillation column and/or splitter operable to separate hydrocarbons. An automated process controller (APC) receives signal from at least one analyzer that provides information about the concentration of at least a first chemical in a first fraction and a second chemical in a second fraction obtained from the distillation column. The APC comprises programming in the form of an algorithm that calculates real-time monetary values for the first chemical and the second chemical and alters the operation of the distillation column to change either the percentage of the first chemical in the second fraction or the percentage of the second chemical in the first fraction, thereby maximizing overall operational profit for the distillation column.

A new catalyst hydroisomerizes C18 paraffins from fatty acids to a high degree to produce a composition with acceptable freeze point which retains 18 carbon atoms in the hydrocarbon molecule for jet fuel. We have discovered a fuel composition comprising at least 14 wt % hydrocarbon molecules having at least 18 carbon atoms and a freeze point not higher than −40° C. The composition also may exhibit a exhibiting a final boiling point of no more than 300° C. The hydroisomerization process can be once through or a portion of the product diesel stream may be selectively hydrocracked or recycled to hydroisomerization to obtain a fuel composition that meets jet fuel specifications.

A new catalyst hydroisomerizes C18 paraffins from fatty acids to a high degree to produce a composition with acceptable freeze point which retains 18 carbon atoms in the hydrocarbon molecule for jet fuel. We have discovered a fuel composition comprising at least 14 wt % hydrocarbon molecules having at least 18 carbon atoms and a freeze point not higher than −40° C. The composition also may exhibit a exhibiting a final boiling point of no more than 300° C. The hydroisomerization process can be once through or a portion of the product diesel stream may be selectively hydrocracked or recycled to hydroisomerization to obtain a fuel composition that meets jet fuel specifications.

The invention concerns a process and a facility for reducing the concentration of heavy polycyclic aromatic compounds (HPNA) in the recycle loop of hydrocracking units, which comprises a fractionation column.

In accordance with this process, a portion of the stream present at the level of at least one plate (I) which is the supply plate or a plate located between the supply plate and said residue evacuation point, or if stripping gas is injected, between the supply plate and said stripping gas injection point, is withdrawn from the fractionation column.

A portion, preferably all, of said withdrawn stream is recycled to the hydrocracking step directly or after optional separation of the gases. The residue is purged in its entirety.

In a preferred embodiment, a portion of the stream present at the level of at least one plate (II) located between the supply plate and the plate for withdrawing the heaviest distillate fraction is also withdrawn from the column. After stripping, all or a portion of the gas is recycled to the column and the liquid is sent for hydrocracking.

The invention concerns a process and a facility for reducing the concentration of heavy polycyclic aromatic compounds (HPNA) in the recycle loop of hydrocracking units, which comprises a fractionation column.

In accordance with this process, a portion of the stream present at the level of at least one plate located between the plate for supplying hydrocracked effluent and the plate for withdrawing the distillate fraction which is the heaviest is withdrawn from the fractionation column and at least a portion of said withdrawn stream is recycled to the column directly or after optional liquid separation, and optionally a portion of said withdrawn stream is recycled to the hydrocracking step directly or after optional gas separation.

The invention concerns a process and a facility for reducing the concentration of heavy polycyclic aromatic compounds (HPNA) in the recycle loop of hydrocracking units, which comprises a fractionation column.

In accordance with this process, a portion of the stream present at the level of at least one plate located between the plate for supplying hydrocracked effluent and the plate for withdrawing the distillate fraction which is the heaviest is withdrawn from the fractionation column and at least a portion of said withdrawn stream is recycled to the column directly or after optional liquid separation, and optionally a portion of said withdrawn stream is recycled to the hydrocracking step directly or after optional gas separation.

The invention concerns a process and a facility for reducing the concentration of heavy polycyclic aromatic compounds (HPNA) in the recycle loop of hydrocracking units, which comprises a fractionation column.

In accordance with this process, a stream is withdrawn from the fractionation column at the level of at least one plate located between the supply plate and the plate for withdrawing the heaviest distillate fraction; the stream is stripped in an external stripping step by a stripping gas, in the presence of a portion of the residue. The separated gaseous effluent is recycled to the column, advantageously as a stripping gas, and the liquid fraction is recycled to the hydrocracking step; a residue is purged in the stripping step.

The invention concerns a process and a facility for reducing the concentration of heavy polycyclic aromatic compounds (HPNA) in the recycle loop of hydrocracking units, which comprises a fractionation column.

In accordance with this process, a stream is withdrawn from the fractionation column at the level of at least one plate located between the supply plate and the plate for withdrawing the heaviest distillate fraction; the stream is stripped in an external stripping step by a stripping gas, in the presence of a portion of the residue. The separated gaseous effluent is recycled to the column, advantageously as a stripping gas, and the liquid fraction is recycled to the hydrocracking step; a residue is purged in the stripping step.

The process is for thermally treating a feed material. The process comprises at least one step performed in a rotating kiln operating under positive pressure with a pressure control system and wherein in the process a sweep gas, that is an inert gas or a substantially non-reactive gas, is injected into the rotating kiln or in the feed stream entering the rotating operating kiln; or at least one step performed in a rotating kiln operating under positive pressure managing system; or at least one step performed in a rotating kiln wherein a sweep gas is injected in the rotating kiln or in the feed stream entering the rotating operating kiln. In step a), or in b) or in step c), the conditions of the thermal treatment are managed in order that the exit stream, after cooling, result in at least one liquid phase that is preferably essentially an oily liquid phase.