Extrusion molding method of high-strength nickel catalyst

Abstract

The invention relates to the technical field of catalyst production, and discloses an extrusion molding method of a high-strength nickel-based catalyst, which comprises the following steps: mixing a nickel-based catalyst precursor, an extrusion aid, a binder and a pore forming agent to obtain a mixture, and carrying out extrusion molding on the mixture in a banded extruder to obtain a molded blank; and drying the formed blank in two steps, and roasting to obtain a catalyst finished product. The extrusion molding method of the catalyst is simple, adopts a mode of uniformly mixing the binder and the pore-forming agent and then adding the binder and the pore-forming agent, effectively improves the mechanical strength of the product through two-step drying, maintains the performance of the catalyst, has the advantages of high production efficiency, low production cost and the like, and is more stable and reliable than an existing extrusion molding method.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst production, in particular to an extrusion molding method for a high-strength nickel-based catalyst. Background Art

[0002] Nickel-based catalysts are widely used in hydrogenation reactions in petrochemical and organic chemicals, such as hydrodecolorization, oil hydrogenation, benzene hydrogenation, aniline hydrogenation, 1,4-butynediol hydrogenation, hydrorefining, etc.

[0003] In industrial use, in order to meet the requirements of the reaction device, give full play to the performance of the catalyst, extend the service life of the catalyst, and ensure the effective transfer of fluid and heat, the nickel-based catalyst needs to be molded into a suitable shape, size and strength. Common molding methods are spray molding, tablet molding and extrusion molding. For catalysts with a molding diameter of 1 to 3 mm, extrusion molding has the advantages of simple process, large production capacity and low cost compared to tablet molding. However, the existing nickel-based catalyst extrusion method has problems such as poor mechanical strength of the catalyst after molding, easy breakage, low production efficiency and high production cost.

[0004] Therefore, a high-strength nickel-based catalyst extrusion molding method is urgently needed to solve the above technical problems. Summary of the invention

[0005] The object of the present invention is to provide a method for extruding a high-strength nickel-based catalyst in view of the deficiencies in the prior art.

[0006] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0007] A method for extruding a high-strength nickel catalyst comprises the following steps: mixing nickel catalyst precursor powder, an extrusion aid, a binder and a pore-forming agent to obtain a mixture, extruding the mixture in an extruder to obtain a formed body; drying the formed body in two steps and then calcining the formed body to obtain a finished catalyst product.

[0008] Preferably, the composition of the nickel-based catalyst precursor powder is as follows: nickel and nickel oxide account for 10-50wt%, auxiliary metals and their oxides account for 1-10wt%, and the rest is aluminum oxide.

[0009] Preferably, the preparation process of the mixture is as follows:

[0010] The nickel catalyst precursor powder is dried and crushed, and then an extrusion aid is added and mixed evenly to obtain a first mixture; a binder and a pore-forming agent are mixed evenly to obtain a second mixture; and the second mixture is added to the first mixture and kneaded to obtain a mixture.

[0011] Preferably, the extrusion aid is at least one of sesbania powder, starch and talcum powder; the added amount of the extrusion aid is 1 to 5 wt % of the nickel-based catalyst precursor powder.

[0012] More preferably, the extrusion aid is sesbania powder, and the added amount is 1.5-2.5 wt % of the nickel-based catalyst precursor powder.

[0013] Preferably, the binder is aluminum sol, and the amount of the binder added is 50-100 wt % of the nickel-based catalyst precursor powder.

[0014] More preferably, the amount of the binder added is 70 to 90 wt % of the nickel-based catalyst precursor powder.

[0015] More preferably, the aluminum sol can be selected from the nitric acid method acidic aluminum sol purchased on the market, or the homemade aluminum sol can be selected.

[0016] Specifically, a preparation process of the aluminum sol is as follows: add SB powder to pure water, stir evenly and then heat to 60-90° C., slowly add concentrated nitric acid to adjust the pH value to less than 2, and keep warm for 1-5 hours to obtain an aluminum sol with an SB powder content of 9-12wt%.

[0017] Furthermore, the preparation process of aluminum sol can also be other methods, as long as the method involves nitric acid in the preparation process of aluminum sol, it can be selected and applied to the present invention.

[0018] Commonly used inorganic acids in the preparation of aluminum sol include hydrochloric acid, nitric acid and sulfuric acid; hydrochloric acid contains chloride ions, which are toxic to the catalyst of the present invention and are generally not used; sulfuric acid is not easy to volatilize, so the present invention uses aluminum sol prepared with the participation of nitric acid.

[0019] Preferably, the pore-forming agent is at least one of polyethylene glycol, methyl cellulose, polyvinyl alcohol and activated carbon, and the added amount of the pore-forming agent is 0.5-3wt% of the nickel-based catalyst precursor powder.

[0020] Specifically, when the binder and the pore former are mixed, the pore former needs to be evenly dispersed in water to form a pore former sol with a pore former content of 6 to 8 wt % and then evenly mixed with the binder.

[0021] More preferably, the pore-forming agent is polyvinyl alcohol, and the added amount is 1-2 wt % of the nickel-based catalyst precursor powder.

[0022] Preferably, the cross-sectional shape of the finished catalyst product is cylindrical or clover-shaped.

[0023] More preferably, the diameter of the finished catalyst product is 1 to 3 mm.

[0024] Preferably, the two-step drying process is: first drying at below 40° C. for 1 to 24 hours, and then drying at 100 to 130° C. for 1 to 12 hours.

[0025] Preferably, the calcination process is: calcination at 400-550° C. for 1-12 hours.

[0026] The purpose of using secondary drying in the present invention is to ensure the strength of the small-sized catalyst obtained in the present invention. The principle of the first low-temperature drying is to make the nitric acid in the finished product volatilize slowly and evenly, promote the uniform reaction of nitric acid and binder on the surface of the grains, expose more hydroxyl groups, and thus improve the strength of the catalyst.

[0027] The present invention provides a high-strength nickel catalyst extrusion molding method, firstly, the nickel catalyst precursor powder is crushed, and then an extrusion aid is added and mixed evenly, and then a binder and a pore-forming agent are mixed evenly and added to the above materials for kneading, and then extrusion molding is performed in an extruder, and a finished product is obtained through two steps of drying and roasting. The extrusion molding method of the present invention is simple, low-cost, effectively improves the mechanical strength of the product, and maintains the performance of the catalyst.

[0028] Beneficial effects:

[0029] The catalyst extrusion molding method of the present invention is simple, adopts the method of adding the binder and the pore-forming agent after they are evenly mixed, and through two-step drying, the mechanical strength of the product is effectively improved, and the performance of the catalyst is maintained. It has the advantages of high production efficiency and low production cost, and is more stable and reliable than the existing extrusion molding method. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0031] All raw materials of the present invention are not particularly limited in their sources and can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

[0032] There is no particular limitation on the purity of all raw materials in the present invention, and the present invention preferably adopts the conventional purity used in the art.

[0033] The devices used in the present invention are not particularly limited and can be any of the commonly used devices in the art.

[0034] In the following examples and comparative examples, the composition of the nickel catalyst precursor powder used is: nickel and nickel oxide account for 26wt%, and the auxiliary metal and its oxide account for 5wt%. The SB powder used contains 72wt% of aluminum oxide.

[0035] Comparative Example 1

[0036] Weigh 30 g of nickel-based catalyst precursor powder, add 3 g of SB powder (high-purity pseudo-boehmite powder) and 0.75 g of sesbania powder and mix thoroughly, then mix 1.5 g of concentrated nitric acid and 28 g of water evenly and add to the above materials, knead thoroughly, and extrude into a cylindrical shape with a diameter of 2.0 mm in an extruder, dry at 105°C for 3 h, and calcine at 480°C for 4 h. The strength is measured by a KQ-2 particle strength tester to be 98 N / cm.

[0037] Comparative Example 2

[0038] Preparation of aluminum sol: Add 22g of pure water and 3g of SB powder into the reactor, stir evenly and heat to 80°C, slowly add 1.5g of concentrated nitric acid, keep warm for 2h, and obtain 26.5g of aluminum sol containing 11.3wt% of SB powder.

[0039] Weigh 30 g of nickel-based catalyst precursor powder and 0.75 g of sesbania powder and mix them thoroughly. Mix 26.5 g of the prepared aluminum sol and 6 g of pure water evenly and add them to the above materials. Knead them thoroughly and extrude them into cylinders with a diameter of 2.0 mm in an extruder. Dry them at 105°C for 3 h and calcine them at 480°C for 4 h. The measured strength is 112 N / cm.

[0040] Comparative Example 3

[0041] The preparation of aluminum sol is the same as that of Comparative Example 2.

[0042] Weigh 30 g of nickel-based catalyst precursor powder and 0.75 g of sesbania powder and mix them thoroughly to obtain material A. Dissolve 0.45 g of polyvinyl alcohol in 6 g of pure water and add it to 26.5 g of the prepared aluminum sol and mix evenly to obtain material B. Add material B to material A, knead them thoroughly, and extrude them into cylinders with a diameter of 2 mm in an extruder. Dry them at 105°C for 3 h, and calcine them at 480°C for 4 h. The measured strength is 125 N / cm.

[0043] Example 1

[0044] Preparation of aluminum sol: Add 22g of pure water and 3g of SB powder into the reactor, stir evenly and heat to 80°C, slowly add 1.5g of concentrated nitric acid, keep warm for 2h, and obtain 26.5g of aluminum sol containing 11.3wt% of SB powder.

[0045] Weigh 30 g of nickel-based catalyst precursor powder and 0.75 g of sesbania powder and mix them thoroughly to obtain material A. Dissolve 0.45 g of polyvinyl alcohol in 6 g of pure water and add it to 26.5 g of the prepared aluminum sol and mix evenly to obtain material B. Add material B to material A, knead it thoroughly, and extrude it into a cylinder with a diameter of 2 mm in an extruder. First, dry it naturally at room temperature 26-30°C for 12 h, then dry it at 105°C for 3 h, and then calcine it at 480°C for 4 h.

[0046] The strength of the finished catalyst product was measured and found to be 150 N / cm.

[0047] Example 2

[0048] The molding method of Example 1 was followed, except that the extrusion aid was replaced by starch. The strength of the obtained catalyst product was measured, and the strength was found to be 145 N / cm.

[0049] Example 3

[0050] The molding method of Example 1 was followed, except that the homemade aluminum sol was replaced with a commercial nitric acidic aluminum sol having the same weight and the same aluminum oxide content. The strength of the obtained catalyst product was measured, and the strength was found to be 146 N / cm.

[0051] Example 4

[0052] The molding method of Example 1 was followed, except that the extruded strips were formed into a clover-leaf shape with a diameter of 2.0 mm. The strength of the obtained catalyst product was measured, and the strength was found to be 148 N / cm.

[0053] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for extruding a high-strength nickel-based catalyst, characterized in that: The method comprises the following steps: mixing nickel catalyst precursor powder, extrusion aid, binder and pore-forming agent to obtain a mixture, extruding the mixture in an extruder to obtain a formed body; drying the formed body in two steps and then calcining the formed body to obtain a finished catalyst product.

2. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The nickel-based catalyst precursor powder comprises the following components: nickel and nickel oxide account for 10-50wt%, auxiliary metal and its oxide account for 1-10wt%, and the rest is aluminum oxide.

3. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The preparation process of the mixture is as follows: The nickel catalyst precursor powder is dried and crushed, and then an extrusion aid is added and mixed evenly to obtain a first mixture; a binder and a pore-forming agent are mixed evenly to obtain a second mixture; and the second mixture is added to the first mixture and kneaded to obtain a mixture.

4. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The extrusion aid is at least one of sesbania powder, starch and talcum powder; the added amount of the extrusion aid is 1-5wt% of the nickel-based catalyst precursor powder.

5. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The binder is aluminum sol, and the amount of the binder added is 50-100wt% of the nickel-based catalyst precursor powder.

6. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The pore-forming agent is at least one of polyethylene glycol, methyl cellulose, polyvinyl alcohol and activated carbon, and the added amount of the pore-forming agent is 0.5-3% of the nickel-based catalyst precursor powder.

7. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The cross-sectional shape of the finished catalyst product is cylindrical or clover-shaped.

8. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The two-step drying process is: first drying at below 40° C. for 1 to 24 hours, and then drying at 100 to 130° C. for 1 to 12 hours.

9. The method for extruding a high-strength nickel-based catalyst according to claim 1, characterized in that: The calcination process is as follows: calcination at 400-550° C. for 1-12 hours.