Process for removing arsine from a hydrocarbon mixture

Abstract

The present invention relates to a process for removing arsine from a hydrocarbon mixture having 2 to 4 carbon atoms. The process comprises contacting the hydrocarbon mixture having 2 to 4 carbon atoms with a sorbent, wherein the sorbent is a metal organic framework (MOF) comprising: a) at least 1 transition metal selected from the group consisting of a Group 1B metal, a Group 2B metal and a Group 4B metal, and b) an organic ligand selected from a di-carboxylic acid compound or a tri-carboxylic acid compound, and wherein the sorbent is subjected to an alcohol treatment.

Description

Technical Field

[0001] This invention relates to the field of chemistry, and more particularly to a method for separating compounds using porous adsorbents. Background Technology

[0002] Removing arsenic compounds from olefins (specifically ethylene and propylene) in production processes is essential to avoid catalyst toxicity. The separation and removal of arsenic compounds from hydrocarbon streams in production processes is carried out using adsorption methods, depending on the type of source, the type of arsenic compound to be removed, and the conditions used for removal. Based on this information, suitable adsorbents can be designed for such arsenic compounds. The most common arsenic compound is arsine because it is volatile and stable, and its boiling point is close to that of propylene.

[0003] Metal oxide adsorbents for removing arsine compounds have been substantially described. Patent document US6960700B1 discloses the synthesis and use of copper metal oxides on an alumina support containing 7 to 10 wt% copper to adsorb arsine compounds from hydrocarbon streams. Although copper oxide adsorbents on supports have been widely used, their application is limited because they can only be used to remove arsine compounds from hydrocarbon streams that do not contain reactive compounds such as acetylene, methylacetylene-propadiene (MAPD), and dienes. This is because copper metal reacts with acetylene compounds under thermal conditions to produce acetylide salts; furthermore, acetylene compounds can react with each other using copper metal oxides as catalysts, causing polymerization and producing undesirable products such as green oil or cuprene.

[0004] Patent document US4962272A discloses the synthesis and use of lead metal oxide on an alumina support, wherein the lead metal oxide has 18% to 24% by weight on the support to adsorb arsine compounds from hydrocarbon streams, including a reuse process of the adsorbent by passing through a heated inert gas containing 1% to 15% water and free of oxygen. However, the use of lead metal oxide can be harmful to human health and the environment. Therefore, there is a need for efficient waste adsorbent treatment systems. Furthermore, compared with adsorbents containing copper components with the same adsorption capacity, lead metal oxide has a lower adsorption capacity for arsine compounds.

[0005] Patent document US4933159A discloses the synthesis and use of metallic silver, silver nitrate compounds, and / or silver metal oxides on a support, wherein the support is alumina, alumina fluoride, silica, silica fluoride, titanium dioxide, and / or magnesium aluminate, to remove arsine compounds, especially trialkylarsine compounds with alkyl groups having 1-6 carbon atoms. The adsorbent contains 2% to 15% by weight of metallic silver. However, the hydrocarbon stream flows through a mixed metal oxide adsorbent of copper and zinc before contacting the aforementioned adsorbent bed containing the silver component.

[0006] Patent documents US20180236434A and WO2019090071A disclose the synthesis and use of bismuth metal oxides on supports, such as alumina, titanium oxide, silicon oxide, cerium oxide, zirconium oxide, magnesium oxide, zeolite, and / or activated carbon, to remove arsine compounds from hydrocarbon streams. The adsorbent contains 2% to 50% wt% bismuth and 5% wt% lead as efficiency enhancers.

[0007] Reports indicate that loading active components onto porous supports not only increases their dispersion but also enhances the contact surface area during reaction or adsorption, thereby increasing adsorption capacity. Commonly used adsorbents include alumina, silica, zeolite, and activated carbon. However, the contact surface area limits the ability to adjust the porosity and properties of the support.

[0008] Metal-organic frameworks (MOFs) are porous materials that have attracted attention for their application in adsorption processes due to their excellent adsorption / desorption properties. Many MOFs possess functional groups that induce specific adsorption and enhance bonding. Furthermore, some MOFs exhibit high contact surface areas and porosity, including more ordered porosity compared to other porous materials. This makes MOFs particularly valuable for their ability to be designed and synthesized for industrial applications.

[0009] In summary, the present invention aims to improve the method for separating arsenic from hydrocarbon mixtures having 2 to 4 carbon atoms by using metal-organic frameworks (MOFs) with high adsorption capacity. Summary of the Invention

[0010] This invention relates to a method for removing arsenic from a hydrocarbon mixture having 2 to 4 carbon atoms. The method includes contacting the hydrocarbon mixture having 2 to 4 carbon atoms with an adsorbent, wherein the adsorbent is a metal-organic framework (MOF) comprising:

[0011] a) at least one transition metal selected from Group 1B, Group 2B, and Group 4B metals, and

[0012] b) Organic ligands selected from dicarboxylic acid or tricarboxylic acid compounds,

[0013] Furthermore, the adsorbent is treated with alcohol. Attached Figure Description

[0014] Figure 1 Arsine separation performance of metal-organic frameworks prepared using different transition metal ions and organic ligands is shown when the molar ratio of transition metal to organic ligand is 2:1.

[0015] Figure 2 Arsine separation performance of metal-organic frameworks containing copper metal and 1,3,5-benzenetricarboxylic acid organic ligands, treated with methanol solvent under different conditions, is shown. Detailed Implementation

[0016] The present invention relates to a method for removing arsenic from a mixture of hydrocarbons having 2 to 4 carbon atoms, which will be described in the following aspects of the invention.

[0017] Unless otherwise stated, any aspect described herein is also intended to include application to other aspects of the invention.

[0018] Unless otherwise stated, the technical or scientific terms used herein have their definitions as understood by one of ordinary skill in the art.

[0019] Any tool, apparatus, method, or chemical named herein means a tool, apparatus, method, or chemical that is commonly operated or used by a person skilled in the art, unless otherwise stated to be a tool, apparatus, method, or chemical specific to this invention only.

[0020] In the claims or description, a singular noun or singular pronoun used with “comprising” means “a”, and also includes “a or more”, “at least one” and “a or more than one”.

[0021] All compositions and / or methods disclosed in this application, as well as the claims, are intended to cover any unexperimented implementations of any element that differs significantly from the present invention and serve the same purpose as those of ordinary skill in the art, although not specifically stated in the claims. Therefore, alternative or similar purposes to the present embodiments, including any minor modifications or adjustments obvious to those skilled in the art, should be interpreted as remaining within the spirit, scope, and inventive concept set forth in the appended claims.

[0022] Throughout this application, the term “about” means any number that appears or is expressed herein and that may be altered or deviated from due to any error by the device, method, or person using the device or method described.

[0023] The following description illustrates embodiments of the invention, but is not intended to limit the scope of the invention in any way.

[0024] This invention relates to a method for removing arsenic from a hydrocarbon mixture having 2 to 4 carbon atoms. The method includes contacting the hydrocarbon mixture having 2 to 4 carbon atoms with an adsorbent, wherein the adsorbent is a metal-organic framework (MOF) comprising:

[0025] a) at least one transition metal selected from Group 1B, Group 2B, and Group 4B metals, and

[0026] b) Organic ligands selected from dicarboxylic acid or tricarboxylic acid compounds,

[0027] Furthermore, the adsorbent is treated with alcohol.

[0028] In one aspect of the invention, the Group 1B metal is selected from copper and silver.

[0029] In one aspect of the invention, the Group 2B metal is selected from zinc.

[0030] In one aspect of the invention, the Group 4B metal is selected from titanium and zirconium.

[0031] Preferably, the metal-organic framework comprises a transition metal, wherein the transition metal is copper, zinc, or zirconium, with copper being the most preferred.

[0032] In one aspect of the invention, the organic ligand is selected from 1,4-benzenediacarboxylic acid, 1,3,5-benzenediacarboxylic acid, 2,6-naphthodicarboxylic acid and 1,2,4,5-benzenediacarboxylic acid, preferably 1,3,5-benzenediacarboxylic acid.

[0033] In one aspect of the invention, the molar ratio of the transition metal to the organic ligand ranges from about 1:1 to 3:1, more preferably about 2:1.

[0034] In one aspect of the invention, the alcohol is selected from methanol, ethanol, propanol and butanol, with methanol being preferred.

[0035] In one aspect of the invention, the adsorbent is treated with alcohol by contacting it with an amount of alcohol of 2 to 5 moles per gram of adsorbent weight.

[0036] In one aspect of the invention, the hydrocarbon having 2 to 4 carbon atoms is selected from ethane, propane, propylene, n-butane and isobutane, preferably propane and propylene.

[0037] In one aspect of the invention, the contact between the hydrocarbon mixture having 2 to 4 carbon atoms and the adsorbent of the invention is carried out in a temperature range of 25°C to 40°C and a pressure range of atmospheric pressure to about 3,000 kPa, preferably in a temperature range of 30°C to 40°C and a pressure range of about 100 kPa to 500 kPa, and most preferably at atmospheric pressure.

[0038] The gas hourly space velocity (GHSV) of the hydrocarbon feed line in the adsorption process is approximately 3,400 to 37,000 mL h⁻¹. -1 Adsorbent weight -1 Preferably 15,000 to 30,000 mL h -1 Adsorbent weight -1 .

[0039] Typically, those skilled in the art can adjust adsorption conditions to suit the type and composition of the hydrocarbon mixture, adsorbent, and column system.

[0040] On the one hand, the method for removing arsenic, wherein the contact between a hydrocarbon mixture having 2 to 4 carbon atoms and the adsorbent of the present invention can be carried out in a continuous fixed-bed adsorption column or a batch adsorption system.

[0041] In another aspect of the invention, the metal-organic framework according to the invention can be prepared by the following steps:

[0042] a) Prepare a solution comprising a mixture containing at least one transition metal selected from Group 1B, Group 2B, and Group 4B metals, and an organic ligand selected from dicarboxylic acid compounds or tricarboxylic acid compounds.

[0043] b) subject the mixture obtained from step a) to a solvothermal process at a defined temperature and time to produce a metal-organic framework, and

[0044] c) subject the material obtained from step b) to alcohol treatment at a defined temperature and time.

[0045] In one aspect of the invention, steps b) and c) may further include drying that can be performed using conventional drying methods such as oven drying, vacuum drying, stirred evaporation, and rotary evaporator drying.

[0046] The following examples are only used to illustrate one aspect of the present invention and do not limit the scope of the present invention in any way.

[0047] Preparation of adsorbent

[0048] Copper-benzenetricarboxylic acid adsorbent

[0049] A solution of 1,3,5-benzenetricarboxylic acid and a solution of copper nitrate trihydrate (Cu(NO3)2·3H2O) in a dimethylformamide solvent were prepared in a defined molar ratio. The copper nitrate trihydrate solution was then added to the 1,3,5-benzenetricarboxylic acid solution and the mixture was stirred. The mixture was then transferred to an autoclave and subjected to a solvothermal reaction at approximately 100°C for approximately 24 hours. When the solvothermal reaction was complete, the solution was cooled to room temperature. The mixture was then filtered and washed with dimethylformamide. The resulting solid was dried in an oven under reduced pressure at approximately 160°C for 24 hours to obtain a metal-organic framework.

[0050] Copper-benzenedicarboxylic acid adsorbent

[0051] The sample was prepared by using the method described for copper-benzenetricarboxylic acid adsorbents, but instead of 1,4-benzenediacarboxylic acid, instead of 1,3,5-benzenetricarboxylic acid.

[0052] Zinc-tricarboxylic acid adsorbent

[0053] A solution of 1,3,5-benzenetricarboxylic acid in dimethylformamide solvent and a solution of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) in dimethylformamide solvent were prepared. The zinc nitrate hexahydrate solution was then added to the 1,3,5-benzenetricarboxylic acid solution, and the mixture was stirred. The mixture was then transferred to an autoclave for solvothermal treatment at approximately 100°C for approximately 24 hours. When the solvothermal treatment was complete, the solution was cooled to room temperature. The mixture was then filtered and washed with dimethylformamide. The resulting solid was dried in an oven under reduced pressure at approximately 160°C for 24 hours to obtain a metal-organic framework.

[0054] Zinc-benzenedicarboxylic acid adsorbent

[0055] The sample was prepared by using the method described for zinc-benzenetricarboxylic acid adsorbents, replacing 1,4-benzenediacarboxylic acid with 1,4-benzenediacarboxylic acid.

[0056] Zirconium-benzenetricarboxylic acid adsorbent

[0057] A solution of 1,3,5-benzenetricarboxylic acid in dimethylformamide and a solution of zirconium oxide octahydrate (ZrOCl2·8H2O) in dimethylformamide were prepared. The zirconium oxide octahydrate solution was then added to the 1,3,5-benzenetricarboxylic acid solution, and the mixture was stirred. The mixture was then transferred to an autoclave and subjected to a solvothermal process at approximately 120°C for approximately 48 hours. When the solvothermal process was complete, the solution was cooled to room temperature. The mixture was then filtered and washed with dimethylformamide. The resulting solid was dried in an oven under reduced pressure at approximately 160°C for 24 hours to obtain a metal-organic framework.

[0058] Zirconium-benzenediacarboxylic acid adsorbent

[0059] The sample was prepared by using the method described for zirconium-benzenetricarboxylic acid adsorbents, but with 1,4-benzenediacarboxylic acid instead of 1,3,5-benzenetricarboxylic acid.

[0060] Copper-benzenetricarboxylic acid adsorbent treated with alcohol

[0061] The copper-benzenetricarboxylic acid adsorbent obtained by the above method was treated with methanol. The metal-organic framework was immersed in methanol for about 18 hours. Then, the mixture was filtered and washed with methanol. The resulting solid was dried under reduced pressure at about 120°C for 12 hours. The adsorbent treated with alcohol was obtained. The treatment was carried out using different amounts of alcohol, namely 2.5 and 5 mol of alcohol per gram of adsorbent.

[0062] Zirconium-phenylenedicarboxylic acid adsorbent treated with alcohol

[0063] The samples were prepared using the above method, employing a zirconium-benzenediacarboxylic acid adsorbent instead of a copper-benzenediacarboxylic acid adsorbent. The treatment was performed using varying amounts of alcohol, with the amount being 2.5 moles of alcohol per gram of adsorbent.

[0064] Arsene adsorption performance test

[0065] The following conditions can be used to test the adsorption performance of arsine.

[0066] Arsene was adsorbed from a hydrocarbon mixture under gaseous conditions using approximately 0.2 g of adsorbent in a continuous adsorption column. The adsorption method was carried out at a temperature of 30 °C, atmospheric pressure, and approximately 30,000 mL / h. -1 Adsorbent weight -1The analysis was conducted at a gas hourly space velocity (GHSV). The hydrocarbon mixture contained propane, propylene, ethyl mercaptan, and arsine compounds. Adsorption was then monitored by measuring the remaining arsine compounds. Ultraviolet spectrophotometry was used, with silver diethyl thiocarbamate compound as an indicator, and gas samples were randomly collected at the desired analysis time.

[0067] To investigate the effects of transition metal type and organic ligand type in a metal-organic framework on the arsine adsorption performance of hydrocarbon mixtures with propane and propylene as main components, adsorbents prepared with different transition metal ions and organic ligands were studied using a 2:1 molar ratio of transition metal to organic ligand. The results are as follows: Figure 1 As shown.

[0068] To investigate the effects of the ratio of transition metals to organic ligands and the effect of alcohol treatment on adsorbents, the adsorption performance of adsorbents containing different types and amounts of transition metals and organic ligands was tested. The results are shown in Table 1 and... Figure 2 As shown.

[0069] Table 1 Performance of different adsorbents in separating arsine from a hydrocarbon mixture at an arsine concentration of 2 mol ppm

[0070]

[0071] As can be seen from the above results, the adsorbent of the present invention has high arsine adsorption and separation performance as described in the present invention.

[0072] The best mode or preferred embodiment of the present invention

[0073] The best mode or preferred embodiment of the present invention is as provided in the specification of the present invention.

Claims

1. A method for removing arsenic from a hydrocarbon mixture having 2 to 4 carbon atoms, the method comprising contacting the hydrocarbon mixture having 2 to 4 carbon atoms with an adsorbent, wherein the adsorbent is a metal-organic framework (MOF), the metal-organic framework (MOF) comprising: a) at least one transition metal selected from Group 1B metals, and b) Organic ligands selected from dicarboxylic acid or tricarboxylic acid compounds, The adsorbent is subjected to alcohol treatment, and the treatment is carried out by contacting the adsorbent with an amount of alcohol of 2 to 5 moles per gram of adsorbent weight.

2. The method of claim 1, wherein the Group 1B metal is selected from copper and silver.

3. The method according to claim 1, wherein the transition metal is copper.

4. The method according to claim 1, wherein the organic ligand is selected from 1,4-benzenediacarboxylic acid, 1,3,5-benzenetricarboxylic acid, 2,6-naphthodicarboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid.

5. The method according to claim 4, wherein the organic ligand is 1,3,5-benzenetricarboxylic acid.

6. The method according to any one of the preceding claims, wherein the molar ratio of the transition metal to the organic ligand is 1:1 to 3:

1.

7. The method according to claim 6, wherein the molar ratio of the transition metal to the organic ligand is 2:

1.

8. The method according to claim 1, wherein the alcohol is selected from methanol, ethanol, propanol and butanol.

9. The method of claim 8, wherein the alcohol is methanol.

10. The method according to claim 1, wherein the hydrocarbon having 2 to 4 carbon atoms is selected from ethane, propane, propylene, n-butane and isobutane.

11. The method according to claim 1, wherein the hydrocarbon having 2 to 4 carbon atoms is propane and propylene.

12. The method of claim 1, wherein the contact is performed in a temperature range of 30°C to 40°C and a pressure range of 100 kPa to 500 kPa.

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