Process For The Conversion Of A Paraffinic Feedstock (Shell)

CATEGORY: PARAFFINS
Process For The Conversion Of A Paraffinic Feedstock (Shell)
United States Patent Application 20160251583
JANSSEN; Andries Hendrik ;   et al.   September 1, 2016
Applicant: SHELL OIL COMPANY
Abstract
The invention relates to a process for the conversion of a paraffinic feedstock that comprises at least 50 wt % of compounds boiling above 370.degree. C. and which has a paraffin content of at least 60 wt %, an aromatics content of below 1 wt %, a naphthenic content below 2 wt %, a nitrogen content of below 0.1 wt %, and a sulphur content of below 0.1 wt %, the process comprising: a) subjecting the paraffinic feedstock to a hydroprocessing step to obtain an at least partially isomerised feedstock; b) separating the at least partially isomerised feedstock into one or more middle distillate fractions and a first residual fraction, wherein step a) is carried out by contacting the paraffinic feedstock with a first catalyst having hydrocracking and hydroisomerising activity and then with a second catalyst having hydrocracking and hydroisomerising activity, wherein the second catalyst is more active in hydroisomerisation and less active in hydrocracking than the first catalyst.
FIELD OF THE INVENTION
[0001] The invention relates to a process for the conversion of a paraffinic feedstock, in particular for the conversion of a paraffinic feedstock derived from a Fischer-Tropsch synthesis process.
BACKGROUND TO THE INVENTION
[0002] It is known to prepare one or more middle distillate fractions such as for example kerosene or gasoil and a base oil precursor or a base oil from a Fischer-Tropsch derived feedstock.
[0003] In WO02/076027 for example, is disclosed a process wherein two or more lubricating base oil grades and a gas oil are obtained by hydrocracking/hydroisomerising a C5+ Fisher-Tropsch product over a catalyst comprising platinum supported on a silica-alumina carrier prepared from amorphous silica-alumina and separating the product thus obtained in one or more gasoil fractions and a base oil precursor fraction. After performing a pour point reducing step, for example catalytic dewaxing, to the base oil precursor fraction, the base oil precursor fraction is separated into two or more base oil grades.
[0004] In WO2009/080681 is disclosed a process to prepare a gas oil and a base oil from a Fischer-Tropsch derived feedstock, wherein the feedstock is subjected to a hydroprocessing step to obtain an isomerised feedstock, separating the isomerised feedstock by means of distillation into at least a gas oil fraction, a heavy distillate fraction and a residual fraction, recycling at least part of the heavy distillate fraction to the hydroprocessing step and reducing the pour point of the residual fraction by means of catalytic dewaxing to obtain the base oil.
[0005] There is, however, still a need for improvement of middle distillate products and base oils from paraffinic feedstocks, such as Fischer-Tropsch derived feedstocks, in particular with respect to the cold flow properties of the base oil and/or middle distillate products.
SUMMARY OF THE INVENTION
[0006] It has now been found that by using two different catalysts in series in the hydrocracking/hydroisomerising of a paraffinic feedstock, in particular a Fischer-Tropsch derived feedstock, wherein both catalysts have hydrocracking and hydroisomerising activity and the second catalyst is more active in hydroisomerisation and less active in hydrocracking compared to the first catalyst, a product is obtained from which lubricating base oils with improved cold flow properties can be prepared. Moreover, one or more middle distillate fractions with improved yield and/or cold flow properties can be obtained.
[0007] Accordingly, the present invention relates to a process for the conversion of a paraffinic feedstock that comprises at least 50 wt % of compounds boiling above 370.degree. C. and which has a paraffin content of at least 60 wt %, an aromatics content of below 1 wt %, a naphthenic content below 2 wt %, a nitrogen content of below 0.1 wt %, and a sulphur content of below 0.1 wt %, the process comprising: [0008] a) subjecting the paraffinic feedstock to a hydroprocessing step to obtain an at least partially isomerised feedstock; [0009] b) separating the at least partially isomerised feedstock into one or more middle distillate fractions and a first residual fraction, wherein step a) is carried out by contacting the paraffinic feedstock with a first catalyst having hydrocracking and hydroisomerising activity and then with a second catalyst having hydrocracking and hydroisomerising activity, wherein the second catalyst is more active in hydroisomerisation and less active in hydrocracking than the first catalyst.
Free Full Text Source:  http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=10&f=G&l=50&co1=OR&d=PG01&s1=shell.AS.&s2=shell.AANM.&OS=AN/shell+OR+AANM/shell&RS=AN/shell+OR+AANM/shell

Integrated Process For Normal Paraffin Alkylation (UOP)

CATEGORY: PARAFFIN ALKYLATION
Integrated Process For Normal Paraffin Alkylation (UOP)
United States Patent Application 20160168053
Kalnes; Tom N. ;   et al.   June 16, 2016
Applicant: UOP
Abstract
An integrated alkylation and disproportionation process and apparatus are described. n-C.sub.4 and n-C.sub.5 are routed to a disproportionation reaction zone for conversion to iso-C.sub.4 and C.sub.6+ isoparaffin-rich product. The iso-C.sub.4 is routed to an alkylation reaction zone and reacted with refinery propylene and butenes to produce alkylate product. The C.sub.6+ isoparaffin-rich product and alkylate product are recovered. Unconverted iso-C.sub.4 and/or olefins are recycled to the alkylation reaction zone, and unconverted n-C.sub.4 and n-C.sub.5 are recycled to the disproportionation reaction zone.
BACKGROUND OF THE INVENTION
[0001] The use of catalytic alkylation processes to produce branched hydrocarbons having properties that are suitable for use as gasoline blending components is well known in the art. Generally, the alkylation of olefins, such as butenes, by isoparaffins, such as isobutane, is accomplished by contacting the reactants with an acid catalyst to form a reaction mixture, settling said mixture to separate the catalyst from the hydrocarbons, and further separating the hydrocarbons, for example, by fractionation, to recover the alkylation reaction product. Normally, the alkylation reaction product is referred to as "alkylate", and preferably contains hydrocarbons having to 7-9 carbon atoms. In order to have the highest quality gasoline blending stock, it is preferred that hydrocarbons formed in the alkylation process be highly branched.
[0002] Due to the increased use of shale crude and tar sands, refiners must now accommodate a growing amount of normal paraffins, such as n-butanes and n-pentanes in the feedstock. Finally, some refineries are trying to manage an increasing amount of light olefin byproducts, such as propylene, produced in existing fluid catalytic cracking (FCC) units.
[0003] There is a need for a more flexible process that can accept these feeds without requiring additional isobutane from an external source.
SUMMARY OF THE INVENTION
[0004] One aspect of the invention is a process for normal paraffin alkylation. In one embodiment, the process includes introducing a feed comprising n-C.sub.4 and n-C.sub.5 paraffins to a disproportionation reaction zone in the presence of a disproportionation catalyst under disproportionation conditions to form a disproportionation mixture comprising iso-C.sub.4 and C.sub.6+ disproportionation products and unreacted n-C.sub.4 and n-C.sub.5 paraffins. The disproportionation mixture is separated in the disproportionation separation zone into at least an iso-C.sub.4-rich stream, a C.sub.6+ isoparaffin-rich stream, and a stream rich in unreacted n-C.sub.4 and n-C.sub.5 paraffins. The iso-C.sub.4-rich stream and an olefin feed stream comprising at least one of ethylene, propylene, and butenes are introduced into an alkylation reaction zone in the presence of an alkylation catalyst under alkylation conditions to produce an alkylation mixture comprising alkylate and unreacted iso-C.sub.4 paraffins. The alkylation mixture is separated in an alkylation separation zone into at least an alkylate-rich stream, and a stream rich in unreacted iso-C.sub.4 paraffins. The stream rich in unreacted n-C.sub.4 and n-C.sub.5 paraffins from the disproportionation separation zone is recycled to the disproportionation reaction zone. The stream rich in unreacted iso-C.sub.4 paraffins from the alkylation separation zone is recycled to the alkylation reaction zone, and at least one of the C.sub.6+ isoparaffin-rich stream from the disproportionation separation zone and the alkylate-rich stream from the alkylation separation zone is recovered.
[0005] Another aspect of the invention is an apparatus for normal paraffin alkylation. In one embodiment, the apparatus includes a disproportionation reaction zone having an inlet and an outlet; a disproportionation separation zone having an inlet and at least one outlet, the inlet of the disproportionation separation zone being in fluid communication with the outlet of the disproportionation reaction zone, an outlet of the disproportionation separation zone being in fluid communication with the inlet of the disproportionation reaction zone; an alkylation reaction zone having at least one inlet and at least one outlet, an inlet of the alkylation reaction zone being in fluid communication with an outlet of the disproportionation separation zone; and an alkylation separation zone having an inlet and at least one outlet, the inlet of the alkylation separation zone being in fluid communication with the outlet of the alkylation reaction zone, an outlet of the alkylation separation zone being in fluid communication with the inlet of the alkylation reaction zone.
Free Full Text Source:  http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=11&f=G&l=50&co1=OR&d=PG01&s1=refinery.TTL.&s2=refinery.AB.&OS=TTL/refinery+OR+ABST/refinery&RS=TTL/refinery+OR+ABST/refinery

Ultra-Tuning of the Rare-Earth fcu-MOF Aperture Size for Selective Molecular Exclusion of Branched Paraffins

CATEGORY: PARAFFINS
Ultra-Tuning of the Rare-Earth fcu-MOF Aperture Size for Selective Molecular Exclusion of Branched Paraffins

Type	Journal Article
Author	Ayalew H. Assen
Author	Youssef Belmabkhout
URL	http://onlinelibrary.wiley.com/doi/10.1002/anie.201506345/abstract
Volume	54
Issue	48
Pages	14353-14358
Publication	Angewandte Chemie International Edition
Date	November 23, 2015
Abstract	Using isoreticular chemistry enables the design and construction of a new rare-earth metal (RE) fcu-MOF with a suitable aperture size for practical steric adsorptive separations. The judicious choice of a relatively short organic building block, namely fumarate, to bridge the 12-connected RE hexanuclear clusters has made possible the contraction of the well-defined RE-fcu-MOF triangular window aperture, the sole access to the two interconnected octahedral and tetrahedral cages. The newly constructed RE (Y3+ and Tb3+) fcu-MOF analogues display unprecedented total exclusion of branched paraffins from normal paraffins. The resultant window aperture size of about 4.7 Å, regarded as a sorbate-size cut-off, enabled a complete sieving of branched paraffins from normal paraffins. The results are supported by collective single gas and mixed gas/vapor adsorption and calorimetric studies.

Methods And Systems For Isomerizing Paraffins (United States Patent Application 20150175505 – UOP)

CATEGORY: PARAFFINS
Methods And Systems For Isomerizing Paraffins (United States Patent Application 20150175505 – UOP)
June 25, 2015
Abstract
Disclosed is a method and system for isomerizing paraffins to improve the isomerate yield, to minimize catalyst content, and to reduce the pressure drop observed in the isomerization reactor. In one embodiment, a method for isomerizing paraffins includes providing a hydrocarbon stream including linear paraffin compounds and passing the hydrocarbon stream to a first lead/lag isomerization reactor pair to isomerize a portion the linear paraffin compounds to branched paraffin compounds. A second portion of the linear paraffin compounds remain as linear paraffins compounds. The method further includes deisohexanizing the branched and linear paraffin compounds to form an overhead product stream, a bottom product stream, and a side-cut stream comprising the linear paraffin compounds and passing the side-cut stream to a second lead/lag isomerization reactor pair to isomerize the linear paraffin compounds to branched paraffin compounds.
TECHNICAL FIELD
[0001] The present disclosure generally relates to methods and systems for isomerizing paraffins. More particularly, the present disclosure relates to methods and systems for isomerizing linear and cyclo-paraffins employing a dual isomerization reactor zone configuration.
BACKGROUND
[0002] Processes for the isomerization of normal and cyclo-paraffins into more highly branched paraffins are widely practiced. Particularly important commercial isomerization processes are used to increase the branching, and thus the octane value of refinery streams containing paraffins of 4 to 8, and especially 5 and 6, carbon atoms. The isomerate is typically blended with a refinery reformer effluent to provide a blended gasoline mixture having a desired research octane number (RON).
[0003] The isomerization process proceeds toward a thermodynamic equilibrium. Hence, the isomerate will still contain normal paraffins and cyclo-paraffins that have low octane ratings and thus detract from the octane rating of the isomerate. Provided that adequate high octane blending streams such as alkylate and reformer effluent is available and that gasolines of lower octane ratings, such as 85 and 87 RON, are in demand, the presence of these normal and cyclo-paraffins in the isomerate has been tolerated.
[0004] Where circumstances demand higher RON isomerates, however, the isomerization processes have been modified by separating the normal and cyclo-paraffins from the isomerate and recycling them to the isomerization reactor. Thus, not only are un-branched paraffins that detract from the octane rating removed from the isomerate, but also their return to the isomerization reactor increases the portion of the feed converted to the more highly desired branched paraffins.
[0005] The most frequently practiced isomerization processes that recycle normal paraffins use a deisohexanizer. A deisohexanizer is one or more distillation columns where an overhead containing branched C.sub.6 paraffins such as dimethylbutanes (2,2-dimethylbuthane and 2,3-dimethylbutane) and lighter components is obtained as the isomerate product for, e.g., blending for gasolines, and a side-stream containing normal hexane and similarly boiling components such as methylpentanes (2-methylpentane and 3-methylpentane), methylcyclopentane, and cyclohexane are recycled back to the isomerization reactor.
[0006] However, it has been observed that when normal and cyclo-paraffins are recycled back to the isomerization reactor, there is an undesirably low product yield due to the requirement to process the recycle stream in addition to the incoming feed stream. Further, it has been observed that the catalyst quantity requirement in the isomerization is also undesirably high, again due to the requirement to process the recycle stream in addition to the incoming feed stream.
[0007] Accordingly, it is desirable to provide economically viable, and simple to operate processes and system to enhance the octane rating of isomerized paraffins. Additionally, it is desirable to provide such methods and systems that minimize the catalyst content required for the isomerization reactor and increase the isomerate product yield. Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.
BRIEF SUMMARY
[0008] The present disclosure generally provides methods and systems for isomerizing paraffins with increased isomerate yield and reduced catalyst content. In one exemplary embodiment, disclosed is a method for isomerizing paraffins that includes providing a hydrocarbon stream including linear paraffin compounds and passing the hydrocarbon stream to a first lead/lag isomerization reactor pair to isomerize a portion the linear paraffin compounds to branched paraffin compounds. A second portion of the linear paraffin compounds remain as linear paraffins compounds. The method further includes deisohexanizing the branched and linear paraffin compounds to form an overhead product stream, a bottom product stream, and a side-cut stream comprising the linear paraffin and cyclo-paraffin compounds and passing the side-cut stream to a second lead/lag isomerization reactor pair to isomerize the linear paraffin compounds to branched paraffin compounds and convert the cyclo-paraffin compounds to branched paraffin compounds.
[0009] In another exemplary embodiment, disclosed is a system for isomerizing paraffins that includes a first lead/lag reactor pair that receives a hydrocarbon stream including linear paraffin compounds and generates an effluent including linear paraffin compounds, branched paraffin compounds, and cyclo-paraffin compounds, a deisohexanizer that receives the effluent from the first lead/lag reactor pair and generates an overhead product stream, a bottoms product stream, and a side-cut stream including the linear paraffin compounds, and a second lead/lag reactor pair that receives the side-cut stream and generates branched paraffin compounds.
Free Full Text Source:  http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=16&f=G&l=50&co1=AND&d=PG01&s1=uop.AS.&OS=AN/uop&RS=AN/uop