CA2199373A1

CA2199373A1 - A method for the demercaptanization of petroleum distillates

Info

Publication number: CA2199373A1
Application number: CA002199373A
Authority: CA
Inventors: Akhmet Mazgarovich Mazgarov; Nailya Gilmutdinovna Bazhirova; Azat Faridovich Vildanov
Original assignee: Individual
Current assignee: Chevron USA Inc
Priority date: 1994-09-27
Filing date: 1995-09-26
Publication date: 1996-04-04
Also published as: EP0783369A4; AU3686195A; CN1071136C; WO1996009891A1; MX9702145A; NO971379D0; EP0783369A1; NO971379L; CN1155853A

Abstract

The demercaptanization of petroleum distillates may be carried out by means of the oxidation of the mercaptans contained therein using the oxygen in the air, at a temperature of about 80 to about 220 ~C, in the presence of about 0.01 to about 10.0 mass % of a water-soluble salt of copper, iron, nickel, or cobalt, on a fibrous carbonaceous material in the form of a woven fabric, felt, rope, or twisted strand, used as a heterogeneous catalyst. The fibrous carbonaceous material used in the process contains oxides of calcium, magnesium, copper, manganese, iron, zinc, and aluminum in an amount of up to about 0.03 mass %.

Description

WO96/09891 PCT~S9~/12339 02 OF PETRO~EUM DISTILLATES

~~ BACKGROUND OF THE T~VENTION

06 The invention relates to the field of the removal of 07 mercaptan sulfur from petroleum distillates by means of 08 oxidation, and may be used in the oil refining industry for 09 the demercaptanization of gasoline, kerosene, and diesel fractions.

12 Methods for the demercaptanization of petroleum distillates 13 are known which involve the oxidation of mercaptans using 14 the oxygen in the air in the presence of a base and lS heterogeneous catalysts containing phthalocyanines of cobalt lC or vanadium deposited onto hard substances, such as 17 activated coal, graphite, alumina, mordenite, silica gel, 18 and others (see USSR Patents Nos. 355805 and 654180; U.S.
l9 Patent Nos. 4,033,860 and 4,48l,106).
21 The principal disadvantages of the indicated methods consist 22 in the insufficiently high degree of mercaptan oxidation in 23 petroleum distillates and the significant alkali consumption 2~ required by the process.
26 From the point of view of its t~hn;cal essence and the 27 result obtained, the method which most closely resembles the 28 method described herein is the method for the 29 demercaptanization of high-boiling-point petroleum distillates by means of mercaptan oxidation using the oxygen 3l of the air, in the presence of a 5% to 20% solution 32 containing an alkali and a heterogeneous phthalocyanine 33 catalyst, comprising cobalt phthalocyanine in an amount 3~ ranging from 0.005 to 0.9 mass %, deposited on a ~ 2 ~
WO96/09891 PCT~S9~112339 01 carbonaceous fibrous material in the form of a carbonaceous 02 or graphite fiber.

0~ The principal disadvantages of this method lie in the 05 insufficiently high level of mercaptan oxidation in 06 petroleum distillates, the low stability of catalytic 07 activity of the catalyst, and the necessity of consuming 08 significant quantities of the alkali substance.

5~MARY OF THE INVENTION

12 The objective of the present invention consists in achieving 13 an increase in the degree of demercaptanization of petroleum 1~ distillates, an increase in the stability of the catalytic activity of the catalyst, and the elimination of the 16 necessity of using significant quantities of the base.

18 Thus, in accordance with the present invention there is 19 provided a method for the demercaptanization of mercaptan-containing petroleum distillates by means of the oxidation 21 of said mercaptans with the oxygen of the air in the 22 presence of a heterogeneous catalyst, said method comprising 23 contacting said mercaptans with oxygen in the presence of a 2~ catalyst comprising a water-soluble salt of copper, iron, nickel, or cobalt, in an amount ranging from about 0.01 to 26 about 10.0 mass %, which is deposited onto a fibrous 27 carbonaceous material, said material containing oxides of 28 metals of variable valence; said method being carried out at 29 a temperature falling within the range of about 80~ to about 200~C.

32 Also provided in accordance with this invention is a 33 catalyst comprising a fibrous carbonaceous material 3~ containing oxides of metals of variable valence, and having - 2 ~ 7 ~
~ WO96/09891 PCT~S9~/12339 0l deposited on said material, in an amount from about 0.0l to 02 about l0.0 mass %, a water-soluble salt of copper, iron, 03 nickel or cobalt.
0~
05 DETATT~n DESCRIPTION OF PREFERRED EMBODIMENTS

07 According to the method of the invention, the stated 08 objective is achieved by providing a method for the 09 demercaptanization of petroleum distillates by means of the oxidation of mercaptans using the oxygen of the air, in the ll presence of a heterogeneous catalyst. For the latter, 12 according to this method, a water-soluble salt of copper, 13 iron, nickel, or cobalt may be used, in an amount ranging l4 from 0.0l to l0.0 mass %, deposited on a fibrous carbon material in the form of a fabric-type material, felt, or 16 rope, containing oxides of metals of variable valence, the 17 process being carried out at a temperature ranging from 18 about 80~ to about 220~C.

For this purpose, a carbonaceous fibrous material is used, 21 containing oxides of calcium, magnesium, copper, manganese, 22 iron, zinc and aluminum, in quantities which provide 23 sufficient basicity for the oxidation of the mercaptans to 24 occur. Typically, this amount will be up to about 0.03 mass %.

27 The distinguishing features of the proposed method consist 28 in the use of a heterogeneous catalyst, containing from 29 about 0.0l to about l0.0 mass % of a water-soluble salt of copper, iron, nickel, or cobalt, on a material which 31 consists of carbonaceous fibers; the use of a carbonaceous 32 fibrous material in the form of a woven fabric (cloth), 33 felt, or rope (twisted strand), containing the oxides of the 34 above mentioned metals of variable valence in an amount of 2 ~ ~ Q 3 ~ 3 WO96/09891 PCT~S95112339 01 up to about 0.03 mass %; and the performance of the process 02 at a temperature ranging from about 80~ to about 220~C.

0~ The cited disting-l;shing features of the proposed method 05 define its novelty and significant departure from the 06 methods known in the art at its present technical level, 07 since the application of a water-soluble salt of copper, 08 iron, nickel or cobalt as a catalyst, with a carbonaceous 09 fibrous material in the form of a woven fabric, felt, or rope (twisted strand) containing oxides of metals of 11 variable valence being used as the bearer of the catalyst, 12 is not described in the literature and allows the process of 13 demercaptanization of petroleum distillates to be performed 1~ with a higher degree of mercaptan oxidation under prolonged use of the catalyst and without the use of a base.

17 Examples of the water-soluble salts of copper, iron, nickel, 18 and cobalt include, but are not limited to, salts of 19 inorganic acids such as the sulfates, chlorides and nitroxides (nitrates) of these metals. Phenylates (i.e., 21 Ph-O-Me-O-Ph where Me is the metal and Ph is phenyl) may 22 also be used. For instance, copper sulfate, copper 23 chloride, copper phenylate, iron sulfate, nickel nitroxide 2~ and cobalt nitroxide are useful in the practice of this invention, with copper phenylate being particularly 26 preferred because it does not carry over into the 27 demercaptanized product.

29 The proposed content of the water-soluble salt of Cu, Fe, Ni, or Co on the carbonaceous fibrous material in an amount 31 ranging from 0.01 to 10.0 mass % is both necessary and 32 sufficient, since with a content of the water-soluble salt 33 of copper, iron, nickel, or cobalt which is less than 0.01 34 mass %, the reguired degree of mercaptan oxidation is not - 2 ~ ~ 9 3 7 3 Wos6/Ogs9l PCT~S95112339 01 achieved. At the same time, the higher limit for the 02 content o~ a water-soluble salt of copper, iron, nickel, or 03 cobalt (10.0 mass ~) is determined by the adsorptive 0~ properties of the carbonaceous fibrous material with respect 05 to the water-soluble salt of copper, iron, nickel, or 06 cobalt.

08 The use of a carbonaceous fibrous material containing oxides 09 of metals having a variable valence in an amount of up to about 0.03 mass % makes it possible to create a necessary 11 and sufficient basicity of the catalyst being used, and, as 12 a result, to eliminate the need to rely on the application 13 of an alkaline substance in the process.
1~
Typical oxides of metals of variable valence which are 16 useful in this invention include, but are not limited to, 17 oxides of calcium, magnesium, iron, manganese, copper, zinc 18 and aluminum. Generally, these oxides are considered to but 19 water-insoluble or only slightly soluble in water.
21 Carbonaceous fibrous materials in the form of a woven 22 fabric, felt, or rope (twisted strand), containing the 23 oxides of metals of variable valence in an amount of up to 24 about 0.03 mass % are industrially produced by a process involving the soaking of the material in solutions of salts 26 of the aforesaid metals, with their subsequent thermal 27 treatment.

29 By conducting the process at a temperature ranging from about 80~ to about 220~C, it becomes possible to carry out 31 the oxidation of mercaptans in petroleum distillates at the 32 temperatures of their liberation, without preliminary 33 cooling, and, as a result, to increase the degree of 3~ mercaptan oxidation and to reduce energy consumption, as WO96/09891 - PCT~S95tl2339 01 well as associated energy costs, for the demercaptanization 02 of petroleum distillates. t 04 The preparation of the proposed catalyst is carried out in 05 accordance with the known method of soaking a carbonaceous 06 fibrous material containing oxides of calcium, magnesium, 07 copper, manganese, iron, zinc, and aluminum in aqueous 08 solutions of the salts of copper, iron, nickel, or cobalt, 09 at the required concentration, with subsequent drying.
11 The proposed method has found approbation under laboratory 12 conditions in examples involving the demercaptanization of a 13 model mixture of dodecylmercaptan in dodecane, a gasoline 1~ fraction (boiling-off range 60~ to 180~C), a kerosene 15 fraction 120~ to 240~C), and a diesel fraction (180~ to 16 350OC).

18 The method is illustrated by the following examples.

20 Example 1 22 Five grams of a heterogeneous catalyst containing 10 mass %
23 copper sulfate on a carbonaceous fabric which further 2~ contains oxides of calcium, magnesium, copper, manganese, 25 iron, zinc, and aluminum in a quantity of 0.03 mass % are 26 loaded into a batch reactor. The copper sulfate is 27 deposited onto the carbonaceous fabric by the method of 28 soaking to saturation using an aqueous solution. Then, 29 35 ml of a model solution of n-dodecylmercaptan in dodecane 30 are loaded into the reactor.

32 The reactor constitutes a cylindrical vessel made of glass, 33 having a capacity of 100 ml, heated from the outside by a 34 metallic spiral. Air is supplied to the reactor from the ~ WO 96/09891 r ~ ~ 9 ~ 3 7 3 PCT~S95/12339 01 bottom; this air is evenly distributed within the reactor 02 space due to the Schott filter which has been installed in 03 the lower part of the reactor. The oxidation of the 0~ mercaptans is carried out with the oxygen of the air, at a oS temperature of 100~C and atmospheric pressure, with air 06 being supplied at a rate of 0.5 l/min. The time of 07 oxidation is 4 minutes.

09 The mercaptan sulfur content in the starting and refined raw material is determined by method of potentiometric 11 titration.

13 The results of the experiment are presented in Table 1.
1~
ExamPles 2-13 17 The demercaptanization of a model mixture of 18 dodecylmercaptan in dodecane is carried out by a method 19 similar to the one described for Example 1. The composition of the catalyst and the results of the experiment are given 21 in Table 1.

23 ExamPles 14-16 2~
The demercaptanization of a model mixture of 26 dodecylmercaptan in dodecane is carried out by a method 27 similar to the one described for Example 1, in the presence 28 of known catalysts. The results of the experiment are given 29 in Table 1.
3~ Example 17 33 Under the same conditions as those described in Example 1, 34 in the presence of a heterogeneous catalyst which contained ~2 ~37 ~
WO96/09891 PCT~S95112339 01 1 mass % copper sulfate on a carbonaceous fabric containing 02 0.03 mass % of the oxides of metals indicated in Example 1, 03 at a temperature of 220~C, over a period of 5 minutes, the 0~ demercaptanization of a diesel fraction having a mercaptan 05 sulfur content equal to 0.02 mass % is carried out.
06 Analysis of the demercaptanized diesel fraction showed the 07 residual content of mercaptan sulfur to be 0.0005 mass %.
08 At the same time, the degree of oxidation of mercaptans in 09 the diesel fraction constitutes 97.5%.

11 Example 18 13 Under the same conditions as those described in Example 1, 1~ in the presence of a known heterogeneous catalyst which contains 0.5 mass % of cobalt disulophthalocyanine on a 16 carbonaceous fabric (without oxides of metals) and a 20%
17 alkali solution, at a temperature of 220~c, over a period of 18 5 minutes, the demercaptanization of a diesel fraction with 19 a mercaptan sulfur content equal to 0.02 mass % is carried out. Analysis of the demercaptanized diesel fraction showed 21 the residual content of mercaptan sulfur to be 0.0075 22 mass %. At the same time, the degree of oxidation of 23 mercaptans in the diesel fraction constitutes 62.5%.
2~
ExamPle 19 27 Under the same conditions as those described in Example 1, 28 in the presence of a heterogeneous catalyst which contains 29 1 mass % of copper sulfate on a carbonaceous fabric containing 0.03 mass % of the oxides of metals described in 31 the example, over a period lasting 3 minutes, the 32 demercaptanization of a gasoline fraction having a mercaptan 33 sulfur content of 0.077 mass % is carried out. Analysis of 3~ the demercaptanized fraction indicated the residual content 01 of mercaptan sulfur to be 0.0001 mass %. At the same time, 02 the degree of oxidation of the mercaptans in the gasoline 03 fraction constitutes 99.87%.
0~
05 ExamPle 20 07 Under the same conditions as those described in Example 1, 08 in the presence of a known heterogeneous catalyst which 09 contains 0.5 mass % of cobalt disulophthalocyanine on a carbonaceous fabric (without oxides of metals) and a 20%
11 alkali solution, at a temperature of 80~C, over a period of 12 time lasting 3 minutes, the demercaptanization of a gasoline 13 fraction with a mercaptan sulfur content of 0.077 mass % is 1~ carried out.
16 Analysis of the demercaptanized fraction demonstrated the 17 residual sulfur content to be 0.028 mass ~.

19 At the same time, the degree of mercaptan oxidation in the gasoline fraction constitutes 63.6%.

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wO 96/09891 r 2 ~ ~ ~ 3 7 -~ PCT~S9S/12339 01 on the basis of the experimental data presented in Table 1 02 and in Examples 17 through 20, it can be seen that by 03 carrying out the treatment process according to the proposed 0~ method, as compared to the known method, it becomes possible 05 to increase significantly (by 15% to 3S%) the degree of 06 mercaptan oxidation in petroleum distillates, and to carry 07 out the process without the use of an alkali substance.

09 The following example illustrates the preservation of high catalytic activity after prolonged use of the catalyst.

12 Example 21 1~ Under the same conditions as those described in Example 1, in the presence of 3 grams of a heterogeneous catalyst 16 containing 1 mass % of copper sulfate on a carbonaceous 17 fabric which contained 0.03 mass % of oxides of metals, a 18 kerosene fraction (120 + 240) originating from the petroleum 19 refinery of Ryazan, having a content of mercaptan sulfur of 0.0082% mass %, is subjected to demercaptanization over a 21 period of 10 minutes. The purified kerosene is drained off, 22 and a fresh portion of kerosene is poured into the reactor 23 and subjected to oxidation. The process is repeated for 2~ several tens of cycles. In a similar manner, the demercaptanization of a kerosene fraction is carried out in 26 the presence of a known catalyst. The results of the 27 experiment are given in Table 2.

29 on the basis of the experimental data presented in Table 2, it can be seen that the proposed method, as compared to the 31 known method, achieves a high stability of the catalytic 32 activity of the catalyst being used under conditions of its 33 repeated and frequent use, without regeneration.
3~

~ WO96/09891 ~~ 2 ~ 9 ~ 3 7 3 PCT~S9S/12339 01 The indicated advantages of the proposed method as compared 02 to the known method, allow significant improvements to be 03 made in the techn;cal and economic indicators of the process 0~ in question.

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Claims

WHAT IS CLAIMED IS:

1. A method for the demercaptanization of mercaptan-containing petroleum distillates by means of the oxidation of said mercaptans with the oxygen of the air in the presence of a heterogeneous catalyst, said method comprising contacting said mercaptans with oxygen in the presence of a catalyst comprising a water-soluble salt of copper, iron, nickel, or cobalt, in an amount ranging from about 0.01 to about 10.0 mass %, said water-soluble salt being deposited onto a fibrous carbonaceous material, said material containing oxides of metals of variable valence; said method being carried out at a temperature falling within the range of about 80° to about 200°C.

2. The method of Claim 1, wherein the fibrous carbonaceous material contains oxides of calcium, magnesium, iron, manganese, copper, zinc, and aluminum in an amount up to about 0.03 mass %.

3. The method of Claim 1 wherein the water-soluble salt is copper sulfate, copper chloride, copper phenylate, iron sulfate, nickel nitroxide, or cobalt nitroxide.

4. The method of Claim 3 wherein the water-soluble salt is copper phenylate.

5. The method of Claim 1 wherein the fibrous carbonaceous material is in the form of a woven fabric, felt or twisted strand.

6. In a method for the demercaptanization of mercaptan-containing petroleum distillates by contacting said mercaptans with oxygen in the presence of a catalyst, the improvement comprising employing a catalyst comprising a fibrous carbonaceous material containing oxides of metals of variable valence, and having deposited on said material, in an amount from about 0.01 to about 10.0 mass %, a water-soluble salt of copper, iron, nickel or cobalt.

7. The method of Claim 6, wherein the fibrous carbonaceous material contains oxides of calcium, magnesium, iron, manganese, copper, zinc, and aluminum in an amount up to about 0.03 mass %.

8. The method of Claim 6 wherein the water-soluble salt is copper sulfate, copper chloride, copper phenylate, iron sulfate, nickel nitroxide, or cobalt nitroxide.

9. The method of Claim 8 wherein the water-soluble salt is copper phenylate.

10. The method of Claim 6 wherein the fibrous carbonaceous material is in the form of a woven fabric, felt or twisted strand.

11. A catalyst comprising a fibrous carbonaceous material containing oxides of metals of variable valence, and having deposited on said material, in an amount from about 0.01 to about 10.0 mass %, a water-soluble salt of copper, iron, nickel or cobalt.

12. The catalyst of Claim 11, wherein the carbon fiber material contains oxides of calcium, magnesium, iron, manganese, copper, zinc, and aluminum in an amount up to about 0.03 mass %.

13. The catalyst of Claim 11 wherein the water-soluble salt is copper sulfate, copper chloride, copper phenylate, iron sulfate, nickel nitroxide, or cobalt nitroxide.

14. The catalyst of Claim 13 wherein the water-soluble salt is copper phenylate.

15. The catalyst of Claim 11 wherein the fibrous carbonaceous material is in the form of a woven fabric, felt or twisted strand.