Bimetallic Mercaptan Conversion Catalyst for Sweetening Liquefied Petroleum Gas at Low Temperature

Patent metadata

Field	Value
Publication number	US-2016199819-A1
Application number	US-201615077431-A
Country	US
Kind code	A1
Filing date	Mar 22, 2016
Priority date	Aug 27, 2014
Publication date	Jul 14, 2016
Grant date	—

Abstract

The present invention relates to a bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature, which is prepared by using an Al 2 O 3 —SiO 2 composite oxide as a carrier to support bimetallic active components vanadium and nickel. The bimetallic mercaptan conversion catalyst has a proper specific surface area and more metal active center sites, and has advantages of simple preparation, an efficient mercaptan conversion ability even at a low temperature, and causing no saturation and polymerization of olefins. The bimetallic mercaptan conversion catalyst exhibits superior mercaptan conversion performance in LPG sweetening, has strong adaptability to starting materials, and can also nearly completely remove trace carbonyl sulfide contained in LPG.

First claim

What is claimed is:

1 . A method for preparing a bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature, comprising the following steps:
(1) mixing 60-80 parts by mass of aluminum hydroxide xerogel and 20-40 parts by mass of silica xerogel uniformly, adding a pore-forming agent and an aqueous nitric acid solution thereto, followed by mixing and kneading, and then extruding the resultant to produce a formed article; (2) air-drying the formed article by placing it at room temperature for 8-15 hours, drying it at 90-120° C. for 3-5 hours, then calcinating it for 3-8 hours by elevating the temperature to 450-620° C. at a heating rate of 2-4° C./min, and subsequently crushing and screening the resultant to produce short-rod-like particles having a size of 4-6 mm, thereby producing an Al 2 O 3 —SiO 2 composite oxide carrier; and (3) loading bimetallic active components, vanadium and nickel, separately onto the Al 2 O 3 —SiO 2 composite oxide carrier by using an isometric impregnation method, and then drying and calcinating it to obtain the bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature.

2 . The method according to claim 1 , wherein the pore-forming agent is used in an amount of 3-5 wt % with respect to the total mass of the mixture of the aluminum hydroxide xerogel and the silica xerogel, the aqueous nitric acid solution is used in an amount of 70-80 wt % with respect to the total mass of the mixture of the aluminum hydroxide xerogel and the silica xerogel, and the aqueous nitric acid solution has a concentration of 5-10 wt %, on a mass percentage basis.

3 . The method according to claim 1 , wherein the Al 2 O 3 —SiO 2 composite oxide carrier has a specific surface area of 150-330 m 2 /g and a pore size of 4-12 nm.

4 . The method according to claim 1 , wherein step (3) comprises:
i) adding a solution containing a soluble salt of vanadium dropwise onto the Al 2 O 3 —SiO 2 composite oxide carrier, then placing it at room temperature for 6-12 hours, drying it at 90-120° C. for 3-5 hours, and calcinating it at 420-550° C. for 3-6 hours, to obtain a catalyst intermediate; and ii) adding a solution containing a soluble salt of nickel dropwise onto the catalyst intermediate, then placing it at room temperature for 6-12 hours, drying it at 90-120° C. for 3-5 hours, and calcinating it at 420-550° C. for 3-6 hours, to obtain the bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature.

5 . The method according to claim 4 , wherein the soluble salt of vanadium includes one or a combination of more of ammonium metavanadate, sodium metavanadate, potassium metavanadate, vanadium acetylacetonate and sodium orthovanadate.

6 . The method according to claim 4 , wherein the soluble salt of nickel includes one or a combination of more of nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, nickel oxalate and nickel acetylacetonate.

7 . The method according to claim 1 , wherein the total content of the bimetallic active components, measured on the basis of the weight of oxides, is 10-40 wt % of the bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature.

8 . The method according to claim 7 , wherein the total content of the bimetallic active components, measured on the basis of the weight of oxides, is 12-30 wt % of the bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature.

9 . The method according to claim 1 , wherein the molar ratio of vanadium to nickel is (0.1-0.8):1.

10 . The method according to claim 1 , wherein, in step (1), the extruded formed article is a clover-shaped long-rod-like formed article having a diameter of 1-3 mm, or a cylindrical long-rod-like formed article having a diameter of 1-3 mm.

11 . The method according to claim 1 , wherein the pore forming agent is sesbania powder.

12 . A bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature, which is prepared by the method according to claim 1 .

13 . Use of the bimetallic mercaptan conversion catalyst for sweetening liquefied petroleum gas at a low temperature according to claim 12 in low-temperature sweetening treatment of liquefied petroleum gas.

14 . The use according to claim 13 , wherein the low-temperature sweetening treatment of liquefied petroleum gas is carried out at a reaction temperature of 55-150° C., a reaction pressure of 1.0-4.0 MPa, a liquid volume hourly space velocity of 2-6 h −1 , and a volume ratio of hydrogen gas to liquefied petroleum gas of 2-8:1.

15 . The use according to claim 13 , wherein, prior to use, the bimetallic mercaptan conversion catalyst is subjected to pre-sulfidation in which sulfur-containing hydrocarbons are used to convert active metal oxides into their metal sulfide form, and the sulfur-containing hydrocarbons are mixed gas of hydrogen gas and hydrogen sulfide containing 6-10 wt % of hydrogen sulfide, or a naphtha fraction containing 1-4 wt % of carbon disulfide or dimethyl disulfide.

16 . The use according to claim 15 , wherein the temperature for the pre-sulfidation is 270-450° C.

Assignees

• China Nat Petroleum Corp
• Univ China Petroleum
• Beijing Cup Green Catalytic Technology Co Ltd

Inventors

• Bao Xiaojun
• Huang Deqi
• Ke Ming
• Wang Lei
• Yuan Pei
• Shi Gang

Classifications

• B01J23/8472 Primary

  Vanadium · CPC title

• C10G29/04

  Metals, or metals deposited on a carrier · CPC title

• C10G2300/202

  Heteroatoms content, i.e. S, N, O, P · CPC title

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/088

  Decomposition of a metal salt · CPC title