JP3253034B2 - How to improve hydrocarbon feedstock quality. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for upgrading hydrocarbonaceous feedstocks that substantially boil in the gasoline range.

[0002]

2. Description of the Related Art One of the main objects in today's oil refining.
One is to meet the increasing environmental demands on product quality and produce gasoline with high octane number. This means that octane standards for gasoline, now aromatics (especially benzene) without lead-containing additives
Means that low olefins and low gasoline vapor pressure must be established.

[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 requirements for product quality and the requirements for high octane number. It has now been found that a gasoline having a high octane number and a reduced aromatics (especially benzene) content can be produced using a quality improvement method comprising a specific sequence of processing steps.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention relates to a quality improvement method of hydrocarbonaceous feedstock substantially boiling in the gasoline range, the method (a) the feed of C ₆ and below hydrocarbon 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 C) subjecting at least a portion of the third hydrocarbon feed stream to a reforming step to produce a reformate stream; and (c) subjecting at least a portion of both the second hydrocarbon feed stream and the reformate stream to a separation treatment to form a normal oil stream. Separating paraffins and optionally mono-isoparaffins from di-isoparaffins; (d) therefrom normal paraffins and optionally mono-paraffins;
A hydrocarbon product stream composed of isoparaffin and a hydrocarbon product stream composed of di-isoparaffin are recovered.

[0005] In this way, a direct reduction of the octane of the resulting gasoline blend pool is established and a substantial reduction in the aromatics (especially benzene) content is realized. In refineries with limitations and / or capacity limitations on 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 obtained from a hydrocarbonaceous feed substantially boiling in the gasoline range may suitably be obtained by distillation. Preferably, the third hydrocarbon feed stream is an adjacent fraction obtained by distillation. Of course, depending on the strictness of fractionation at the cut point of each fraction selected by distillation, adjacent fractions may have some overlap. For example, the first hydrocarbon feed stream may also include a C ₇ hydrocarbons. Hydrocarbonaceous feeds boiling in the gasoline range are preferably obtained by distillation of crude oil or from catalytic cracking, but are obtained by other cracking processes such as, for example, thermal cracking, delayed coking, visbreaking and flexiking. You can also. Such gasoline feedstocks generally contain unacceptable amounts of sulfur and nitrogen and it is advantageous if they are hydrotreated before being subjected to the process according to the invention.

[0006] A small portion of the second hydrocarbon feed, for example 10% by weight, can suitably be co-treated with the third hydrocarbon feed 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 may be introduced into the isomerization unit. The isomerate obtained from this can then be transferred to a gasoline blending 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 can preferably be co-treated with the first hydrocarbon feed stream as described above, at least a portion of the resulting gasoline fraction is preferably 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
The part is separated, for example, by distillation into a light gasoline fraction consisting of hydrocarbons in the C ₆ -C ₁₀ range and a heavy gasoline fraction consisting of C ₈ and higher hydrocarbons. At least one of the obtained light gasoline fractions
The portion is then subjected to a separation treatment in step (c), while at least a portion of the resulting heavy gasoline fraction is transferred directly to a 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 process. In this manner, the first hydrocarbon product stream composed of normal paraffin can be recovered, and the second hydrocarbon product stream composed of di-isoparaffin can be recovered.

[0008] In step (c), a separation process can be established, preferably by transferring at least a portion of both the reformate and the second hydrocarbon stream to a separation zone, the separation zone comprising: 5
X 4.5 Angstroms or less pore size and shaped so that normal paraffins can be selectively adsorbed over mono-isoparaffins, di-isoparaffins, other multi-branched paraffins, cyclic paraffins and aromatic hydrocarbons Consists of shape selective segregating molecular sieves. In this way, normal paraffin can be selectively separated from mono-isoparaffin and di-isoparaffin. 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 can suitably be co-treated with the third hydrocarbon feed in step (b). Preferably, the complete first hydrocarbon product stream can be co-processed in step (b). At least a portion of the hydrocarbon product stream comprising normal paraffins can also be used, preferably as a suitable chemical feed. For example, it can be used as a feed for a highly selective cyclization process.

Preferably, the process according to the invention is carried out in such a way that both normal paraffins and mono-isoparaffins are separated from di-isoparaffins. This can preferably be established by transferring at least a portion of both the second hydrocarbon feed stream and the reformate stream to a separation zone, which is 5.5 × 5.5-4.5. It consists of shape selective segregating molecular sieves with an intermediate pore size of 5 x 4.5 angstroms (excluding 4.5 x 4.5 angstroms), the pore size allowing normal paraffin and mono-isoparaffin intrusion. Large enough to prevent the ingress of isoparaffins, other multibranched paraffins, cyclic paraffins and aromatic hydrocarbons. In this way, normal paraffin and mono-isoparaffin can be selectively separated from di-isoparaffin. Then, a first hydrocarbon product stream consisting of both normal paraffins and mono-isoparaffins and a second hydrocarbon product stream consisting of di-isoparaffins can 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. Preferably, the complete first hydrocarbon product stream can be co-processed in step (b). At least a portion of the first hydrocarbon product stream may also be used as a suitable chemical feed, preferably 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 multiselective adsorptive molecular sieve system with specific separation properties can be used. Preferably, the multiple separation 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 multibranched paraffins, cyclic paraffins and aromatics. A first molecular sieve shaped to be selectively adsorbed relative to the aromatic hydrocarbon;
Di-isoparaffin having an intermediate pore size of 5.5 x 5.5-4.5 x 4.5 angstroms (excluding 4.5 x 4.5 angstroms) and mono-isoparaffins (and any residual normal paraffins); It consists of a second molecular sieve formed to be adsorbed relative to other multibranched paraffins, cyclic paraffins and aromatic hydrocarbons, which can be directly transferred to a refined gasoline blending pool. In operation, a second hydrocarbon feed stream is
At least a portion of both the reformate and the first reformate are first transferred to a first separation zone, which comprises a first shape-selective separation molecular sieve as described above and comprises a first hydrocarbon product comprising normal paraffins. A stream and a second hydrocarbon product stream comprising mono- and di-isoparaffins are produced. Is then latter hydrocarbon product stream is transferred to a second separating molecular sieve or we second separation zone of shape selective as described above. Then, a third hydrocarbon product stream consisting of mono-isoparaffin can be recovered and a fourth hydrocarbon product stream consisting of di-isoparaffin can be recovered. At least a portion of the first and third hydrocarbon product streams may suitably be co-treated in step (b). Preferably, the complete first and third hydrocarbon product streams can be co-processed in step (b). However, at least a portion of these streams may also be used as a suitable chemical feed, preferably as described above.

[0011] The multiple selective adsorption molecular sieve system as described above is composed of at least two types of molecular sieves. These can be arranged in separate vessels or can be arranged in a single vessel in a laminar flow mode. This first molecular sieve can be a calcium 5 Å zeolite, or another sieve having a similar pore size, ie, 4.5 × 4.5 Å pore size. Preferably, the first sieve need not be dimensioned to adsorb all of the normal paraffins, but the second molecular sieve need not function as a normal paraffin adsorption sieve. The second sheave in this process sequence is an 8- and 10-membered ring and 5.5 × 5.5-4.5 × 4.5 Å (excluding 4.5 × 4.5 Å).
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 Angstroms zeolite and ferrierite having pore openings of similar dimensions as ZSM-5 and other similar shape selective materials. Other examples of crystalline sieves include aluminophosphates, silicoaluminophosphates and borosilicates. Aluminophosphate, silicoaluminophosphate and borosilicate molecular sieves that can be used as the second molecular sieve are 5.5 ×
5.5-4.5 × 4.5 angstroms (4.5 ×
(Excluding 4.5 angstroms). Molecular sieves can also be composed of open pore zeolites that have been ion exchanged with cations to reduce the effective pore size of the sieve to within the above size ranges.

When using a multi-selective adsorptive molecular sieve system, the order of the sieves is very important, whether in separate containers or in stacked form. If the sieve is replaced, the method loses its effect because the larger sieve is quickly filled with normal paraffin and prevents effective adsorption of mono-isoparaffin. Each sieve used in the multiselective adsorption molecular sieve system should be arranged in a process sequence that first allows full adsorption of normal paraffinic hydrocarbons and then adsorbs mono-isoparaffins. Each of these sieves can be supplied with a common desorption stream, or each sieve can have its own desorption stream. The desorbent is preferably a gaseous substance such as, for example, a stream of hydrogen gas. Preferably, at least a portion of the resulting reformate is transferred to a hydrogenation unit and then subjected to any of the above separation processes. In the process according to the invention as described above, the third hydrocarbon feed may preferably be subjected to a separation treatment before the reforming step, to separate normal paraffins and, if necessary, mono-isoparaffins from di-isoparaffins, Recovers the first separated effluent of normal paraffin and performs at least a part of the second separated effluent of di-isoparaffin on the reforming step.

In this way, the amount and low
It is established that can substantially reduced in reforming processes in the production of hydrocarbons having octane. The separation process upstream of the reforming step may preferably be established by transferring at least a portion of the third hydrocarbon feed to a separation zone, which may be 4.5 x 4.5 Angstroms or more. A shape-selective separation molecular sieve having the following pore size and formed so that normal paraffin can be selectively adsorbed as compared to mono-isoparaffin, di-isoparaffin, other multibranched paraffin, cyclic paraffin and aromatic hydrocarbon. Be composed. In this way, normal paraffin can be selectively separated from mono-isoparaffin and di-isoparaffin. The first separated effluent substantially consisting of normal paraffin can then be recovered and the second separated effluent consisting of di-isoparaffin can be at least partially subjected to a reforming step.

[0015] Preferably, the separation treatment upstream of the reforming step can be performed so as to separate both normal paraffin and mono-isoparaffin from di-isoparaffin. This is preferably established by transferring at least a portion of the third hydrocarbon feed stream to a separation zone, which has an intermediate pore size (4. 5 x 5.5-4.5 x 4.5 Angstroms). (Excluding 0.5 x 4.5 Angstroms) with a shape-selective separation molecular sieve having a pore size sufficient to allow normal paraffin and mono-isoparaffin to enter, but preventing di-isoparaffin entry. To be restricted. In this way, normal paraffins and mono-isoparaparaffins can be selectively separated from di-isoparaffins, other multibranched paraffins, cyclic paraffins and aromatic hydrocarbons. The first separated effluent containing both normal paraffins and mono-isoparaffins can then be recovered and the second separated effluent containing di-isoparaffins can be at least partially subjected to a reforming step. Preferably, the separation treatment upstream of the reforming step comprises separating normal paraffins first from mono-isoparaffins and di-isoparaffins and then mono-paraffins.
It is done to separate isoparaffin from di-isoparaffin. For this purpose, the above-described multiselective adsorption molecular sieve system can be used.

Preferably, normal and / or mono-
At least a portion of the separated effluent comprising isoparaffins can be used as a suitable chemical feed as described above. When using a multiselective adsorptive molecular sieve system both upstream and downstream of the reforming step, the normal paraffin and mono-isoparaffin present first are separated from di-isoparaffin and then still present in the second separated effluent. Alternatively, normal paraffin and mono-isoparaffin produced in the reforming step
Separated from isoparaffin. The use of a multiselective adsorptive molecular sieve system both upstream and downstream of the reforming step is extremely attractive because it gives product flexibility along with product quality. Separation processes upstream and downstream of the reforming step can preferably be performed in the same separation zone. Preferably, butane is added to the resulting gasoline in a gasoline blending pool to provide the maximum allowable RVP (Reid Vapor Pressure).
All gasoline with specifications can be obtained.

In the reforming step, any conventional reforming catalyst can be used. Preferably, in the reforming step, a catalyst having considerable (dehydro) cyclization activity is used. Examples of conventional reforming catalysts include platinum, for example, from 0.005% to 10.0% by weight.
Is a platinum-containing catalyst present in the range of The catalytic metal having a reforming function is preferably a metal of Periodic Table VIII of the element.
Noble metals from the group III, such as platinum and palladium. The reforming catalyst can be present alone, but can also be mixed with a binder. It will be appreciated that the use of precious metal containing reforming catalysts generally requires pretreatment as a catalytic hydrogenation of the feedstock to be upgraded. In this way, nitrogen and sulfur compounds can be removed from the feedstock, or these compounds will significantly reduce the performance of the reforming catalyst. Preferably, the reforming step can be performed under conventional reforming conditions. Typically, this step involves 450
It is carried out at a temperature of ５550 ° C. and a pressure of 3 to 20 bar. The reaction section in which the reforming step is performed can be suitably separated into several stages or several reactors.

[0018]

The present invention will be further described with reference to the following examples. The method according to the invention was carried out according to the flow chart shown in FIG. Hydrocarbon feedstock substantially boiling in the gasoline range and having the properties set forth in Table 1
Through the distillation column 2 where the feed was separated into three hydrocarbon feed streams. A first hydrocarbon feed stream comprising hydrocarbons in the C ₅ -C ₆ range was withdrawn via line 3 and introduced into the isomerizer 4. The isomerized effluent obtained therefrom was withdrawn via line 5 and introduced into gasoline blending pool 6, while the gas fraction was withdrawn via line 7. A second hydrocarbon feed stream comprising hydrocarbons in the C ₆ -C ₁₀ range was withdrawn via path 8. C ₈ and path 9 more third hydrocarbon feed stream comprising hydrocarbons
And introduced into the reforming reactor 10. Reforming at a temperature of 510 ° C., a pressure of 10.6 bar,
1.8kg / kg / hr weight space-time velocity and 510N
Performed at a hydrogen / feed ratio of 1 / kg. Commercially available reforming catalysts are composed of platinum and tin on alumina.
The resulting reformate was then withdrawn via line 11 and introduced into distillation column 12. The reformate is separated into a light fraction and a gasoline fraction consisting of the gaseous fraction and C ₅ -C ₆ hydrocarbons in the distillation column 12. The gas fraction was withdrawn via line 13, the light fraction was co-processed with the first hydrocarbon feed via line 14, and the gasoline fraction was withdrawn via line 15. Second
The hydrocarbon feed stream was introduced into path 15 via path 8 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 5.5-4.5 x 4.5 Angstroms (excluding 4.5 x 4.5 Angstroms).

The first molecular sieve 17 selectively adsorbs normal paraffin preferentially over mono-isoparaffin, di-isoparaffin, cyclic paraffin and aromatic hydrocarbon. A fraction consisting of normal paraffin was withdrawn via path 19. The separated effluent, from which normal paraffin had been substantially removed, was withdrawn via line 20 and contacted with Molecular Sieve No. 2 (18). Mono-isoparaffin was adsorbed on this particular sieve, while di-isoparaffin and other multi-branched paraffins, cyclic paraffins and aromatic hydrocarbons passed through the sieve without adsorption. A fraction consisting of mono-isoparaffin is withdrawn via line 21, where the remaining separated effluent (di-isoparaffin fraction) substantially free of normal paraffin and mono-isoparaffin is withdrawn via line 22, Introduced into pool 6. Fractions withdrawn via pathways 19 and 21 were co-processed in a reforming step.

The 100 pbw feed in path 1 produced various product fractions in the following amounts: 16.8 pbw first hydrocarbon feed (path 3) 51.0 pbw second hydrocarbon feed ( Path 8) 32.2 pbw third hydrocarbon feed stream (Path 9) 59.8 pbw reformate fraction (Path 11) 11.7 pbw gas fraction (Path 13) 7.0 pbw light fraction (Path 14) 41 0.1 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 (path 21) 5 pbw di-isoparaffin fraction (path 22).

In the gasoline blend pool 6, 3.7 pbw of butane was added to the resulting gasoline via route 23. In this way, 9 with the maximum allowed RVP standard
0.0 pbw total gasoline was obtained. All gasolines obtained in blended gasoline pool 6 have the properties shown in Table 2. As is evident from Table 2, a very attractive gasoline in terms of octane number and aromatics (especially benzene) content can be obtained by the practice of the invention. In conventional upgrading processes, gasolines with very high aromatics content (especially benzene) are obtained.

[0022]

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

[0023]

TABLE 2 Gasoline properties: RON 95.0 total aromatics (volume%) 34.0 benzene (volume%) 0.9 naphthenes (volume%) 23.4 RVP (kPa) 62

[Brief description of the drawings]

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

[Explanation of symbols]

 2 Distillation tower 4 Isomerizer 6 Gasoline blending pool 10 Reforming reactor 12 Distillation tower 16 Separation zone 17, 18 Molecular sieve

Continued on the front page (72) Inventor Marius Geraldas Frederikas Peutz 2596 H.R., The Hague, Karel Wan-Bilantlan 30 (56) References JP-A-2-273628 (JP, A) 40-26193 (JP, B1) European Patent 462673 (EP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10G 35/00-35/24 C10G 61/00-61/08 EPAT (QUESTEL)

Claims (9)

(57) [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 separating the third hydrocarbon feed stream comprising a second hydrocarbon feed stream and the C ₈ and higher hydrocarbons consisting -C ₁₀ range hydrocarbons; (b) at least a portion of the third hydrocarbon feed stream Undergoing a reforming step to produce a reformate stream; (c) subjecting at least a portion of both the second hydrocarbon feed stream and the reformate stream to a separation treatment to form a mixture of normal paraffins and, optionally, mono-isoparaffins. -Separated from isoparaffin; (d) normal paraffin and optionally mono- therefrom-
A method for improving the quality of a hydrocarbonaceous feedstock, comprising recovering a hydrocarbon product stream comprising isoparaffin and a hydrocarbon product stream comprising di-isoparaffin. 2. The method according to claim 1, wherein the second hydrocarbon feed stream comprises a hydrocarbon in the C ₆ -C ₈ range. 3. The process according to claim 1, wherein in step (c) both normal paraffins and mono-isoparaffins are separated from di-isoparaffins. 4. The process according to claim 3, wherein the normal paraffin is first separated from mono-isoparaffin and di-isoparaffin, and then the mono-isoparaffin is separated from di-isoparaffin. 5. In step (c), at least a portion of both the second hydrocarbon feed stream and the reformate are subjected to the same separation treatment to recover a first hydrocarbon product stream comprising normal paraffins and di-isoparaffins. The method according to any one of claims 1 to 3, wherein a second hydrocarbon product is recovered. 6. The process 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 and consist of normal paraffins. A process according to any one of the preceding claims, wherein the first separated effluent is recovered and at least a portion of the second separated effluent 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 method according to claim 8, wherein the normal paraffin is first separated from mono-isoparaffin and di-isoparaffin, and then the mono-isoparaffin is separated from di-isoparaffin.