JPH02202991A - Isomerization of hydrocarbon into paraffin isomer - Google Patents

Abstract

PURPOSE: To perform the isomerization of a paraffin hydrocarbon material highly selectively without being affected by N impurities by bringing the material into contact with a specific catalyst under specified conditions.

CONSTITUTION: A hydrocarbon material (e.g. n-hexadecane) in the range of a distillate having a b.p. range of 165-343°C and contg. a 20C or lower paraffin component is isomerized by bringing it into contact, at 199-454°C under a pressure of 790-7,000 kPa, with a catalyst contg. a group VIII metal (e.g. Pt) and crystalline zeolite (e.g. ZSM-22) having specified hydrocarbon adsorptivity and micropores and having an SiO₂/Al₂DO₃ ratio of at least 20/1.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a process for paraffin isomerization of hydrocarbon feedstocks in the distillate range.

[Prior art] In order to lower the pour point of hydrocarbon feedstock in the distillate range, n-
Various contact methods have been proposed to isomerize paraffins. However, many of the available feedstocks contain nitrogen impurities (usually at least 20 ppm) that tend to contaminate conventional paraffin isomerization catalysts.

[Problem M to be Solved by the Invention] The present invention attempts to provide a method for solving this problem.

[Means for Solving the Problems] The present invention provides hydrocarbon raw materials in the distillate range having a boiling point range of 165 to 343°C and a paraffin component which is a molecule having 20 or less carbon atoms, preferably 16 or less, to paraffin. A method of isomerizing a paraffin-containing raw material: (1) P/PG is 0.1 and 5 for i-hexane.
(2) the sorption ratio of n-hexane to 0-xylene in volume percentages greater than 3 based on the adsorption amount determined at 80°C for 0-xylene at 540°C (100°F); n-hexane/3-methylpentane (3MP)/2 at 1 atm)
゜The weight ratio of 3-dimethylbutane (DMB) is l/1/i
from a mixture where the rate constant ratio '3MP/kDlilB is greater than 2 measured at 540°C (1000°F)
contacting a crystalline aluminosilicate zeolite catalyst with pores defined by its ability to selectively crack 3-methylpentane over doubly branched 2,3-dimethylbutane; Zeolite S 10 containing Group I metals and at least 20:l
*/ A lt O3 ratio and the above contact is 19
a temperature of 9 to 454 degrees Celsius (390 to 850 degrees Fahrenheit) and 7
90~7000kPa (100~l O00psig)
It consists in a method carried out at a pressure of

The above contact is performed at t 825-4240 kPa (250-6
00 psig).

The rP/POJ used here is based on the literature, e.g.
The Dynamical Character of Atsorption
ter orA, dsorpt 1on) J. H. DeBoer (J,) [deBoer), 2nd edition,
Oxford University Press
d U n1versity Press), (
196B);
Relative pressure defined as the ratio of the partial pressure of turbait to its vapor pressure at the sorption temperature. The rate constant ratio "317P" DMB is determined by the usual method from -order kinetics with the following formula: to = (1/Tc) in (1/ l -a) where k
is the rate constant of each component, Tc is a constant time, and ε is
This is the partial conversion rate of each component.

The crystalline aluminosilicate zeolite used in the present invention has: (1) P/Po of 0.1 and 5 for n-hexane;
0°C, sorption ratio of n-hexane to 0-xylene greater than 3 by volume based on the adsorption amount determined at 80°C for 0-xylene and (2) 540°C (1000°F), t O1 ,kPa(
n-hexane/3-methylpentane (3MP
)/23-dimethylbutane (DMB) weight ratio is l/1
/1 to a rate constant ratio greater than 2 measured at 540°C (1000°F) to 3 MP/kDl.
llB than doubly branched 2,3-dimethylbutane.
It has a pore defined by its ability to selectively crack methylpentane.

The zeolite catalysts described above are effective in the isomerization of n-paraffins, are resistant to nitrogen contamination, and contain special fine particles that are effective in eliminating most of the nitrogen-containing organic molecules that enter the catalyst. It has been found that this is particularly the case for distillate feedstocks as a result of the pore size. To this end, while intermediate pore zeolites have previously been described as being somewhat limited to isomerization due to their pore size, the present invention is a To provide an unexpectedly effective method for the isomerization of hydrocarbon feedstocks in the oil range.

The intermediate pore zeolite group that can be used in the method of the invention is Z
Including SM-22, ZSM-23 and ZSM-35.

ZSM-22 is described in U.S. Patent No. 4,556,477,
M-23 is described in the same No. 4076842, and ZSM-35 is described in the same No. 4016245.

The Group 1 metal used in the catalyst in the process of the invention is preferably selected from platinum, palladium, iridium, osmium, rhodium and ruthenium. The metal preferably accounts for 0.01% to l based on the weight of the zeolite.
It is incorporated into the zeolite by ionic conversion in a content of θ%, preferably 01-3%. Zeolite is silica,
It may be supported by a binder selected from alumina, silica-alumina and titania.

When the feedstock is a distillate range feedstock with a boiling point range of 165-343°C (330-850'F), the catalyst in the process of the present invention will meet the conditions necessary for the isomerization of the paraffins in the feedstock. Below shows resistance to contamination by nitrogen compounds.

Moreover, in the presence of zeolite catalysts, the boiling point of hydrocarbon feedstocks with substantially paraffinic components can be increased from 5 to 11 °C (10 to 20'P ) can be lowered. As a result, the feedstock can be processed without significantly reducing the yield in the distillate range. The product obtained by the process of the invention contains a significantly higher amount of isoparaffinic compounds, ie branched hydrocarbons, than straight-chain hydrocarbons. Therefore, the yield of non-parefin distillate is significantly increased.

Therefore, while other methods are useful for reducing paraffin content by hydrocracking, the process of the present invention maintains high yields in the distillate range while n- It has been found to be unexpectedly effective in reducing paraffin content.

[Example] The method of the invention is illustrated by the following examples.

Example 1 (comparative example) 3550 kPa (500 psig), 277°C (531
0F), H,/HC= L 3 , L and ILH
P using n-hexadecane at 8V (liquid time-space velocity)
The isomerization selectivity of t/Z SM 5 /A lyos was measured.

At n-Cl3 conversion rate of 77%, selectivity (l C+6
The ratio of yield to n-C+e conversion) was only 0.30. Then, add benzoquinoline to nc+ so that the nitrogen content is 20 ppm. Added to raw materials. n-C, @reaction temperature 30°C (54°F) to maintain 77% conversion.
It needed to be elevated. The isomerization selectivity increased to 0.43.

Pt/ZSM-22/A as described in Example 1
The isomerization selectivity of l*Oz was measured. 302℃ (576
n-Cta conversion of 85 wt. As benzoquinoline 2
When 0 ppm nitrogen was added, the reaction temperature was increased by 29°C (52°F) to maintain conversion, but no change in isomerization selectivity was observed. Therefore, this catalyst showed better isomerization selectivity in the presence of nitrogen contaminants compared to ZSM-5 on pure feed.

Example 3 Pt/ZSM23/AI as described in Example 1
, tested the isomerization selectivity of O3. 320°C (608°
F) had an n-C+e conversion of 69% by weight and an isomerization selectivity of 0.
．． 60 was obtained. After adding benzoquinoline, n-C
, , required only a 20°C (38″F) increase in reaction temperature.
It showed higher isomerization selectivity and better nitrogen resistance compared to S.

Pt/29M-35/A under the conditions described in Example 1
l*Os was used for the isomerization of Rho C1. 30
An n-C+s conversion of 76% by weight and an isomerization selectivity of 0.50 at 7°C (585°F) were obtained. When adding 20 ppm of nitrogen as benzoquinoline, the reaction temperature was avoided to increase by 60°C (108°F) to maintain conversion, however, the isomerization selectivity increased to 0.70. PL/Z
SM-5/A1.031: In comparison, a larger temperature increase was required to maintain the conversion activity of nC,.
Higher isomerization selectivities were obtained for nitrogen-containing feeds and pure feeds using pi/zSM-35/A1103.

The results of the above examples are summarized in Table 1 below.

Table 1 *: Isomerization selectivity is n-C1, 1C1 relative to conversion rate
11 yield ratio.

Claims (1)

[Claims] 1, boiling point range of 165 to 343°C and number of carbon atoms is 2
1. A method for paraffin isomerizing a hydrocarbon feedstock in the distillate range having a paraffin component having a molecular weight of 0 or less, the method comprising:
The paraffin-containing feedstock is: (1) o-xylene with a P/P_0 of 0.1 and a volume percentage of o-xylene determined at 50°C for n-hexane and 80°C for o-xylene; (2) At 540°C and 101 kPa, the weight ratio of n-hexane/3-methylpentane/2,3-dimethylbutane is 1/
Pore defined by the ability to selectively crack 3-methylpentane over 2,3-dimethylbutane from a mixture that is 1/1 with a rate constant ratio k_3_M_P/k_D_M_B greater than 2 measured at 540 °C. contacting a catalyst comprising a crystalline zeolite having a Group VII metal and having at least 20:1 zeolite SiO
_2/Al_2O_3 ratio and the above contact is 199
An isomerization process carried out at a temperature of ~454<0>C and a pressure of 790-7000 kPa. 2. The crystalline aluminosilicate catalyst is ZSM-22, Z
The method of claim 1, wherein the catalyst is selected from SM-23 and ZSM-35. 3. The method according to claim 1 or 2, wherein the Group VIII metal is a metal selected from platinum, palladium, iridium, osmium, rhodium and ruthenium. 4. Process according to any one of claims 1 to 3, wherein the metal is incorporated into the zeolite by ion exchange with a metal content of 0.01 to 10.0% by weight. 5. Claim 4, wherein the metal content is 0.1 to 3.0% by weight.
Method described. 6. A method according to any of claims 1 to 5, wherein the zeolite is supported by a binder selected from silica, alumina, silica-alumina and titania. 7. A method according to any one of claims 1 to 6, wherein the paraffin component has molecules having up to 16 carbon atoms.