JPH05247473A - Process for upgrading hydrocarbonaceous feedstock - Google Patents

Abstract

PURPOSE: To obtain a gasoline having a high octane number and a decreased content of an aromatic substance (especially benzene), by treating a hydrocarbonaceous feedstock substantially boiling in the gasoline range in a specified order.

CONSTITUTION: A hydrocarbonaceous feedstock substantially boiling in the gasoline range is upgraded by the following treatment of (a) to (d): (a) separating a feedstock 1 through a distillation column 2 into a 6 or smaller C first hydrocarbon feed stream 3, a 6-10C second hydrocarbon feed stream 8, and a 8 or greater C third hydrocarbon feed stream 9; (b) subjecting at least part of the third hydrocarbon feed stream 9 to a reforming step 10 to produce a reformate stream 11; (c) subjecting at least part of both the second hydrocarbon feed stream 8 and the reformate stream 11 to a separation treatment 17 and 18, wherein a normal paraffin 19 and optionally a mono-isoparaffin 21 are separated from a di-isoparaffin 22; and (d) recovering the streams 19, 21 and 22 in a separation zone 16 (17 and 18).

COPYRIGHT: (C)1993,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for improving the quality of hydrocarbonaceous feedstocks which are substantially boiling in the gasoline range.

[0002]

BACKGROUND OF THE INVENTION One of the main objectives in today's oil refining.
One is to produce gasoline with a high octane number while meeting increasing environmental demands regarding product quality. This means that the octane standard for gasoline is now used for aromatics (especially benzene) without lead-containing additives.
It means that it must be established by reducing the gasoline content and the olefin content as well as the gasoline vapor pressure.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process for producing gasoline which meets both the increasing environmental and high octane number requirements regarding product quality. It has now been determined that a quality enhancement process consisting of a particular sequence of processing steps can be used to produce gasoline with high octane numbers and reduced aromatics (especially benzene) content.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a process for improving the quality of hydrocarbonaceous feedstocks that are substantially boiling in the gasoline range, which method comprises: (a) feeding the feedstock to C ₆ and lower hydrocarbons. separated into a first hydrocarbon feed stream and the C ₆ -C ₁₀ range of the second hydrocarbon feed stream comprising hydrocarbons and C ₈ and a third hydrocarbon feed stream comprising more hydrocarbons consisting of; (b ) At least a portion of the third hydrocarbon feed stream is subjected to a reforming step to produce a reformate stream; (c) At least a portion of both the second hydrocarbon feed stream and the reformate stream is subjected to a separation treatment to produce a normal stream. Paraffin and optionally mono-isoparaffin are separated from di-isoparaffin; (d) normal paraffin and optionally mono-paraffin from there.
It is characterized by recovering a hydrocarbon product stream composed of isoparaffin and a hydrocarbon product stream composed of di-isoparaffin.

In this way, a direct octane boost of the resulting gasoline blend pool is established, while a substantial reduction of aromatics (especially benzene) content is realized. In refineries with limitations and / or capacity limitations related to octane-based gasoline production, this octane enhancement allows for increased gasoline production. Preferably,
The second hydrocarbon feed stream consists C ₆ -C ₈ range hydrocarbons. A third hydrocarbon feed stream derived from a hydrocarbonaceous feedstock that is substantially boiling in the gasoline range may suitably be obtained by distillation. Suitably, the third hydrocarbon feed stream is the adjacent fraction obtained by distillation. Of course, some overlap may occur in adjacent fractions depending on the strictness of fractionation at the cut points of each fraction selected in the distillation. For example, the first hydrocarbon feed stream may include C ₇ hydrocarbons. Hydrocarbonaceous feedstocks boiling in the gasoline range are preferably obtained by distillation of crude oil or by catalytic cracking, but also by other cracking processes such as thermal cracking, delayed coking, visbreaking and flexicoking. You can also Gasoline feedstocks of this kind generally contain unacceptable amounts of sulfur and nitrogen, and it is advantageous if they are hydrotreated before they are subjected to the process according to the invention.

A small portion of the second hydrocarbon feed stream, for example 10% by weight, can preferably be co-treated with the third hydrocarbon feed stream in step (b). Preferably, it is possible to third simultaneous processing and a hydrocarbon feed stream in step (b) at least a portion of C ₆ -C ₇ hydrocarbon fraction in the second hydrocarbon feed stream. Suitably, at least a portion of the first hydrocarbon feed stream may be introduced into the isomerization unit. The isomerate obtained from this can then be transferred to the gasoline blend pool. Suitably, be separated prior to the separation treatment in step (c) into a light fraction and a gasoline fraction consisting of the gaseous fraction and C ₅ -C ₆ hydrocarbons by at least a portion, for example, distillation of the reformate flow it can. While the light fraction may preferably be co-treated with the first hydrocarbon feed stream as described above, at least a portion of the resulting gasoline fraction may preferably be subjected to a separation treatment in step (c). it can.

In another suitable embodiment of the process according to the invention, at least one of the gasoline fractions obtained is
Parts are separated, for example by distillation, into a light gasoline fraction consisting of hydrocarbons in the C _{6 to} C ₁₀ range and a heavy gasoline fraction consisting of C ₈ and higher hydrocarbons. At least one of the light gasoline fractions obtained
Parts are then subjected to the separation treatment in step (c), while at least one part of the heavy gasoline fraction obtained is transferred directly to the gasoline blending pool. Preferably, in step (c), at least a portion of both the second hydrocarbon stream and the reformate are subjected to the same separation treatment. In this way, it is possible to recover a first hydrocarbon product stream consisting of normal paraffins and a second hydrocarbon product stream consisting of di-isoparaffins.

In step (c), the separation process can be preferably established by transferring at least part of both the reformate and the second hydrocarbon stream to the separation zone, which separation zone is 4. 5
Normal paraffins having a pore size of 4.5 angstroms or less and formed so as to be selectively adsorbed against mono-isoparaffins, di-isoparaffins, other multi-branched paraffins, cyclic paraffins and aromatic hydrocarbons. It is composed of shape-selective molecular sieves. In this way, normal paraffins can be selectively separated from mono-isoparaffins and di-isoparaffins. Then, a first hydrocarbon product stream consisting essentially of normal paraffins and a second hydrocarbon product stream consisting of di-isoparaffins can be recovered. At least a portion of the first hydrocarbon product stream may suitably be co-treated with the third hydrocarbon feed stream in step (b). Suitably, the complete first hydrocarbon product stream may be co-treated in step (b). At least a portion of the hydrocarbon product stream consisting of normal paraffins may also be used, preferably as a suitable chemical feedstock. For example, it can be used as a feedstock for highly selective cyclization processes.

The process according to the invention is preferably carried out to separate both normal paraffins and mono-isoparaffins from di-isoparaffins. This is preferably established by transferring at least a portion of both the second hydrocarbon feed stream and the reformate stream to the separation zone, which is 5.5 x 5.5-4.5. It is composed of shape-selective separation molecular sieves with an intermediate pore size of 5 x 4.5 angstroms (excluding 4.5 x 4.5 angstroms), which allows the entry of normal paraffins and mono-isoparaffins Large enough to prevent the ingress of isoparaffins, other multi-branched paraffins, cyclic paraffins and aromatic hydrocarbons. In this way, normal paraffins and mono-isoparaffins can be selectively separated from di-isoparaffins. A first hydrocarbon product stream consisting of both normal paraffins and mono-isoparaffins and a second hydrocarbon product stream consisting of di-isoparaffins can then be recovered. Suitably in step (b) at least a portion of this first hydrocarbon product stream may be co-treated with a third hydrocarbon feed stream. Suitably the complete first hydrocarbon product stream may be co-treated in step (b). At least a portion of the first hydrocarbon product stream may also suitably be used as a suitable chemical feedstock as described above.

Preferably, normal paraffins are first separated from mono-isoparaffins and di-isoparaffins, while mono-isoparaffins are then separated from di-isoparaffins. For this purpose, a multi-selective adsorption molecular sieve system with specific separation properties can be used. Preferably, the multi-separating sieve system to be used has a pore size of 4.5 x 4.5 Angstroms or less and normal paraffins are mono-isoparaffins, di-isoparaffins, other multi-branched paraffins, cyclic paraffins and aromas. A first molecular sieve formed so as to be selectively adsorbed in contrast to a group hydrocarbon,
Mono-isoparaffins (and any residual normal paraffins) with di-isoparaffins, having an intermediate pore size of 5.5 x 5.5-4.5 x 4.5 angstroms (excluding 4.5 x 4.5 angstroms). It can consist of other multi-branched paraffins, cyclic paraffins and a second molecular sieve formed to adsorb in contrast to aromatic hydrocarbons, which can be transferred directly to the gasoline blending pool. In operation, the second hydrocarbon feed stream and at least a portion of both the reformate and the reformate are first transferred to the first separation zone, which is separated from the first shape-selective separation molecular sieve as described above. To produce a first hydrocarbon product stream containing normal paraffins and a second hydrocarbon product stream containing mono- and di-isoparaffins. The latter hydrocarbon product stream is then transferred to a second separation zone from a shape-selective second separation molecular sieve as described above. Then, a third hydrocarbon product stream consisting of mono-isoparaffins can be recovered and a fourth hydrocarbon product stream consisting of di-isoparaffins can be recovered. At least a portion of the first and third hydrocarbon product streams may suitably be co-treated in step (b). Suitably, the complete first and third hydrocarbon product streams may be co-treated in step (b). However, at least a portion of these streams may also preferably be used as the preferred chemical feedstock as described above.

The multi-selective adsorption molecular sieve property as described above is composed of at least two kinds of molecular sieves. They can be placed in separate containers, or they can be placed in a single container in a layered flow manner. This first molecular sieve can be a calcium 5 angstrom zeolite or another sieve with similar pore size, i.e. a pore size of 4.5 x 4.5 angstroms. Although it is not necessary to dimension the first sieve to adsorb all of the normal paraffins, it is preferred that the second molecular sieve does not have to function as a normal paraffin adsorption sieve. The second sheave in this process sequence is an 8- and 10-membered ring and 5.5 x 5.5 to 4.5 x 4.5 angstroms (excluding 4.5 x 4.5 angstroms).
And a molecular sieve having an intermediate pore size of

The preferred second molecular sieve of the present invention is exemplified by ferrierite molecular sieve. The ferrierite sieve is preferably present in the hydrogen form, but can alternatively be exchanged with alkali metal or alkaline earth metal cations or transition metal cations.
The molecular sieves of the present invention include calcium 5-Angstrom zeolite and ferrierite and other similar shape-selective materials with pore openings of similar dimensions as ZSM-5. Other examples of crystalline sieves include aluminophosphates, silicoaluminophosphates and borosilicates. The aluminophosphate, silicoaluminophosphate and borosilicate molecular sieve that can be used as the second molecular sieve is 5.5 ×.
5.5-4.5 x 4.5 Angstrom (4.5 x
(Excluding 4.5 Å) with an intermediate pore size. The molecular sieves can also be composed of air-pore zeolites that have been ion-exchanged with cations to reduce the effective pore size of the sieve to within the above size range.

When using a multi-selective adsorptive molecular sieve system, the order of the sieves is very important, either in separate vessels or in a stacked type. If the sieve is replaced, the process loses effectiveness as the larger sieve fills more rapidly with normal paraffin and prevents effective adsorption of mono-isoparaffins. Each of the sieves used in the multi-selective adsorption molecular sieve system should be arranged in a process sequence that first allows for sufficient adsorption of normal paraffin hydrocarbons and then adsorbs mono-isoparaffins. Each of these sheaves can be supplied with a common desorption flow, or each sheave can have its own desorption flow. The desorbent is preferably a gaseous substance such as a stream of hydrogen gas. Suitably, at least a portion of the resulting reformate is transferred to a hydrogenator and then subjected to any of the above separation processes. In the process according to the invention described above, it is also possible to subject the third hydrocarbon feed stream to a separation treatment, preferably before the reforming step, to separate the normal paraffins and optionally the mono-isoparaffins from the di-isoparaffins. Recover the first separated effluent stream of normal paraffins and subject at least a portion of the second separated effluent stream of di-isoparaffins to the reforming step.

It is thus confirmed that the amount of make gas and the production of hydrocarbons having a low ontan number can be substantially reduced in the reforming process. The separation process upstream of the reforming step can preferably be established by transferring at least a portion of the third hydrocarbon feed stream to the separation zone, which separation zone is 4.5 x 4.5 Angstroms or less. A shape-selective separation molecular sieve in which normal paraffins have the following pore sizes and are shaped to selectively adsorb mono-isoparaffins, di-isoparaffins, other multi-branched paraffins, cyclic paraffins and aromatic hydrocarbons. Composed. In this way, normal paraffins can be selectively separated from mono-isoparaffins and di-isoparaffins. A first separated effluent stream consisting essentially of normal paraffins may then be recovered and a second separated effluent stream consisting of di-isoparaffins may be at least partially subjected to a reforming step.

Preferably, the separation treatment upstream of the reforming step can be carried out so as to separate both normal paraffins and mono-isoparaffins from di-isoparaffins. This is preferably established by transferring at least a portion of the third hydrocarbon feed stream to the separation zone, which has an intermediate pore size (4 x 5.5-4.5 x 4.5 angstroms). Composed of shape-selective separated molecular sieves (excluding .5 × 4.5 angstroms), the pore size is sufficient to allow entry of normal paraffins and mono-isoparaffins, but prevent entry of di-isoparaffins Restricted to do so. In this way, normal paraffins and mono-isoparaparaffins can be selectively separated from di-isoparaffins, other multi-branched paraffins, cyclic paraffins and aromatic hydrocarbons. A first separated effluent stream containing both normal paraffins and mono-isoparaffins may then be recovered and a second separated effluent stream containing di-isoparaffins may be at least partially subjected to a reforming step. Preferably, the separation process upstream of the reforming step involves separating normal paraffins first from mono-isoparaffins and di-isoparaffins and then mono-paraffins.
Isoparaffins are separated from di-isoparaffins. For this purpose, the multi-selective adsorption molecular sieve system described above can be used.

Preferably, normal and / or mono-
At least a portion of the separated effluent stream comprising isoparaffin can be used as the preferred chemical feedstock as described above. When using a multi-selective adsorption molecular sieve system both upstream and downstream of the reforming step, the normal paraffins and mono-isoparaffins present first are separated from the di-isoparaffins and then still present in the second separation effluent. Alternatively, normal paraffin and mono-isoparaffin produced in the reforming process are
Separate from isoparaffin. The use of a multi-selective adsorptive molecular sieve system both upstream and downstream of the reforming process is extremely attractive as it provides product flexibility as well as product quality. Separation treatments upstream and downstream of the reforming step can preferably be carried out in the same separation zone. Preferably, butane is added to the gasoline obtained in a gasoline blending pool to obtain a maximum allowable RVP (Reid Vapor Pressure).
It is possible to obtain all gasoline with specifications.

Any conventional reforming catalyst can be used in the reforming step. Preferably, in the reforming step, a catalyst with considerable (dehydro) cyclization activity is used. An example of a conventional reforming catalyst is, for example, 0.005 wt% to 10.0 wt% platinum.
It is a platinum-containing catalyst present in the range of. The catalytic metal with reforming function is preferably element VIII of the Periodic Table of the Elements.
Noble metals from the group, such as platinum and palladium. The reforming catalyst can be present alone, but can also be mixed with the binder. It will be appreciated that the use of noble metal-containing reforming catalysts generally requires pretreatment as a catalytic hydrotreatment of the feedstock to be upgraded. In this way, nitrogen compounds and sulfur compounds can be removed from the feed, otherwise they will significantly reduce the performance of the reforming catalyst. Suitably, the reforming step may be carried out under conventional reforming conditions. Typically this step is 450
It is carried out at a temperature of ˜550 ° C. and a pressure of 3 to 20 bar. The reaction section in which the reforming process is carried out can preferably be divided into several stages or several reactors.

[0018]

EXAMPLES The present invention will be further described below with reference to examples. The method according to the invention was carried out according to the flow chart shown in FIG. Route 1 is a hydrocarbonaceous feedstock that has substantial boiling in the gasoline range and has the properties shown in Table 1.
Was introduced into the distillation column 2 via where the feed was separated into three hydrocarbon feed streams. A first hydrocarbon feed stream consisting of hydrocarbons in the C _{5 to} C ₆ range was withdrawn via line 3 and introduced into the isomerization unit 4. The isomerized effluent obtained therefrom was withdrawn via line 5 and introduced into the gasoline blending pool 6, while the gaseous fraction was withdrawn via line 7. A second hydrocarbon feed stream consisting of hydrocarbons in the C _{6 to} C ₁₀ range was withdrawn via line 8. A third hydrocarbon feed stream consisting of C ₈ and higher hydrocarbons is passed through line 9
And was introduced into the reforming reactor 10. Reforming at a temperature of 510 ° C., a pressure of 10.6 bar,
Weight space-time velocity of 1.8 kg / kg / hr and 510 N
Performed at a hydrogen / feed ratio of 1 / kg. Commercially available reforming catalysts consist of platinum and tin on alumina.
The obtained modified oil was then withdrawn via the route 11 and introduced into the distillation column 12. In the distillation column 12, the reformed oil was separated into a gas fraction, a light fraction composed of C _{5 to} C ₆ hydrocarbons, and a gasoline fraction. The gas fraction was withdrawn via line 13, the light fraction was co-treated with the first hydrocarbon feed stream via line 14, and the gasoline fraction was withdrawn via line 15. Second
The hydrocarbon feed stream was introduced via line 8 into line 15 and was transferred along with the gasoline fraction to a separation zone 16 containing molecular sieves 17 and 18. Molecular sieve No. 1 (17) is a commercially available zeolite having a pore size of 4.5 × 4.5 Å or less. Molecular sieve 18 (referred to as molecular sieve No. 2) has an intermediate pore size of 5.5 x 5.5 to 4.5 x 4.5 angstroms (excluding 4.5 x 4.5 angstroms).

The first molecular sieve 17 selectively adsorbs normal paraffins preferentially over mono-isoparaffins, di-isoparaffins, cyclic paraffins and aromatic hydrocarbons. The fraction consisting of normal paraffin was withdrawn via route 19. The separated effluent stream from which normal paraffins were substantially removed was withdrawn via line 20 and contacted with Molecular Sieve No. 2 (18). Mono-isoparaffin was adsorbed on this specific sieve, while di-isoparaffin and other multi-branched paraffins, cyclic paraffins and aromatic hydrocarbons were not adsorbed and passed through the sieve. The fraction consisting of mono-isoparaffins is withdrawn via line 21, where the residual separated effluent substantially depleted of normal paraffins and mono-isoparaffin (di-isoparaffin fraction) is withdrawn via line 22 and blended gasoline It was introduced into pool 6. Fractions withdrawn via routes 19 and 21 were co-treated in a reforming step.

The 100 pbw feedstock in Route 1 produced various product fractions in the following amounts: 16.8 pbw first hydrocarbon feed stream (Route 3) 51.0 pbw second hydrocarbon feed stream ( Route 8) 32.2 pbw third hydrocarbon feed stream (Route 9) 59.8 pbw reformate fraction (Route 11) 11.7 pbw gas fraction (Route 13) 7.0 pbw light fraction (Route 14) 41 .1 pbw gasoline fraction (path 15) 21.8 pbw isomerate fraction (path 5) 2.0 pbw gas fraction (path 7) 12.9 pbw normal paraffin fraction (path 19) 79.2 pbw separated effluent (path) 20) 14.7 pbw mono-isoparaffin fraction (route 21) 64. 5 pbw di-isoparaffin fraction (route 22).

3.7 pbw butane in gasoline blending pool 6 was added to the resulting gasoline via route 23. In this way, 9 with the maximum allowed RVP standard
Total gasoline of 0.0 pbw was obtained. The total gasoline obtained in the blended gasoline pool 6 has the properties shown in Table 2. As is apparent from Table 2, gasoline which is extremely attractive in terms of octane number and content of aromatic substances (particularly benzene) can be obtained by the practice of the present invention. In the conventional upgrading process, gasoline is obtained which has a very high content of aromatic substances, especially benzene.

[0022]

Table 1 Table 1 C (wt%): 84.9 H (wt%): 15.1 S (ppm): 15 d (15/4): 0.729 I.S. B. P. (° C, ASTM): 50 10 wt% rec: 82 30 wt% rec: 100 50 wt% rec: 110 70 wt% rec: 128 90 wt% rec: 149 F.I. B. P. : 183 RON: 55 naphthene weight%: 34 aromatic substance weight%: 6

[0023]

[Table 2] Table 2 Properties of gasoline : RON 95.0 wholly aromatic substance (volume%) 34.0 benzene (volume%) 0.9 naphthene (volume%) 23.4 RVP (kPa) 62

[Brief description of drawings]

1 is a flow chart of a method according to the present invention.

[Explanation of symbols]

 2 Distillation column 4 Isomerization device 6 Gasoline blending pool 10 Reforming reactor 12 Distillation column 16 Separation zone 17, 18 Molecular sieve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Marius Geraldas Fredericas Peutz The Netherlands 2596 H.A.R., Hague, Karl van Wilantran 30

Claims (9)

[Claims] 1. A quality improvement method of hydrocarbonaceous feedstock substantially boiling in the gasoline range, the first hydrocarbon feed stream and the C ₆ consisting of (a) a feedstock C ₆ and below hydrocarbon To a second hydrocarbon feed stream consisting of hydrocarbons in the range of to C ₁₀ and a third hydrocarbon feed stream consisting of C ₈ and higher hydrocarbons; (b) at least a portion of the third hydrocarbon feed stream. Is subjected to a reforming step to produce a reformate stream; (c) at least a portion of both the second hydrocarbon feed stream and the reformate stream is subjected to a separation process to dilute normal paraffins and optionally mono-isoparaffins. -Detached from isoparaffins; (d) from which normal paraffins and optionally mono-
A method for improving the quality of a hydrocarbonaceous feedstock, comprising recovering a hydrocarbon product stream composed of isoparaffin and a hydrocarbon product stream composed of di-isoparaffin. 2. The method of claim 1 wherein the second hydrocarbon feed stream comprises hydrocarbons in the C _{6 to} C ₈ range. 3. The method according to claim 1, wherein both normal paraffins and mono-isoparaffins are separated from di-isoparaffins in step (c). 4. The process according to claim 3, wherein the normal paraffin is first separated from the mono-isoparaffin and the di-isoparaffin and then the mono-isoparaffin is separated from the di-isoparaffin. 5. In step (c), at least a portion of both the second hydrocarbon feed stream and the reformate is subjected to the same separation treatment to recover a first hydrocarbon product stream consisting of normal paraffins and di-isoparaffins. The method according to any one of claims 1 to 3, wherein the second hydrocarbon product consisting of 6. The method of claim 5, wherein in step (b) at least a portion of the first hydrocarbon product stream comprising normal paraffins is co-treated with a third hydrocarbon feed stream. 7. At least a portion of the third hydrocarbon feed stream is first subjected to a separation treatment prior to the reforming step to separate normal paraffins and optionally mono-isoparaffins from di-isoparaffins, consisting of normal paraffins. A method according to any one of claims 1 to 5, wherein the first separated effluent stream is recovered and at least a portion of the second separated effluent stream comprising di-isoparaffin is subjected to a reforming step. 8. The method of claim 7 wherein both normal paraffins and mono-isoparaffins are separated from di-isoparaffins. 9. The process according to claim 8, wherein the normal paraffins are first separated from the mono-isoparaffins and the di-isoparaffins and then the mono-isoparaffins are separated from the di-isoparaffins.