Paraffin hydrogenation catalyst and synthesis method and application thereof
Technical Field
The invention relates to a paraffin hydrogenation catalyst, a synthesis method and application thereof.
Background
The paraffin wax is solid at normal temperature and has relatively large average molecular weight (300-500) and C20-C40 carbon atoms. The purpose of the paraffin hydrofining process is to keep the basic constitution of alkane and remove cancerogenic substances such as polycyclic aromatic hydrocarbon represented by 3, 4-benzopyrene, sulfur, nitrogen, oxygen, metal and the like in non-hydrocarbon.
At present, along with the increasing reduction and inferior quality of high-wax-content crude oil resources, the shortage and inferior quality of paraffin resources are caused, meanwhile, the continuous increase of Chinese paraffin yield and the increase of market demand varieties are caused, so that the demands for processing inferior paraffin and high-melting-point wax are increased, and the high-quality requirements of international markets on petroleum wax products cannot be met by the conventional petroleum wax hydrofining catalyst and process technology. Therefore, it is necessary to study a hydrofining catalyst with high pore diameter and high activity and develop a new advanced refining process technology suitable for treating inferior petroleum waxes.
CN200410050732.8 discloses a paraffin hydrofining catalyst and a preparation method thereof. The method comprises the steps of firstly preparing a macroporous Al 2O3 additive, uniformly mixing pseudo-thin alumina powder and macroporous Al 2O3 with a proper proportion, and then forming, drying and roasting to prepare an Al 2O3 carrier; and loading the VIII group and VIB group metal compounds and the auxiliary agent by an impregnation method, and then drying and roasting to obtain the final catalyst product.
CN01129503.1 discloses a paraffin hydrofining catalyst, its preparation method and application. The method comprises the steps of adding titanium dioxide into alumina, kneading, extruding strips for molding, drying and roasting to prepare the carrier; wherein the active component W-Mo-Ni-P is impregnated and loaded on the carrier by a one-step method, and the active component is prepared into water solution with required concentration by ammonium tungstate, ammonium molybdate, nickel nitrate and phosphoric acid at room temperature.
The technical proposal disclosed in the method adopts alumina to prepare the carrier, and in the paraffin hydrofining process, the cracking reaction of the paraffin is not allowed, and the paraffin hydrofining catalyst needs to have weaker surface acid property, so the development of the non-alumina carrier has important significance for preparing the paraffin hydrofining catalyst suitable for treating inferior petroleum waxes.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a paraffin hydrofining catalyst and a synthesis method and application thereof. The paraffin hydrofining catalyst prepared by the method has proper surface acid property and larger pore diameter, is used for petroleum wax hydrogenation, and shows excellent hydrofining performance.
The invention provides a synthesis method of a paraffin hydrofining catalyst, which comprises the following steps:
(1) Mixing a biomass raw material with a potassium-containing inorganic substance, and performing heat treatment on the mixture;
(2) Carbonizing the material obtained in the step (1), and then carrying out steam treatment;
(3) Repeating the step (2) for 1-5 times to obtain an intermediate, washing and drying to obtain carbon powder;
(4) Preparing microemulsion containing active metal;
(5) Kneading the carbon powder obtained in the step (3), the microemulsion obtained in the step (4), an extrusion aid and a binder, molding, drying and roasting to obtain the paraffin hydrofining catalyst.
Further, in the step (1), the biomass raw material is one or more of wood, straw, fruit shell, starch, bamboo and biological residues. The biomass raw material is firstly subjected to drying and crushing treatment, and the drying conditions are as follows: drying at 80-225 deg.c for 3-9 hr to obtain crushed wood chip of 100-400 mesh, preferably 200-400 mesh.
Further, in the step (1), the inorganic matter containing potassium is one or more of potassium carbonate, potassium hydroxide and potassium oxide.
Further, in the step (1), the addition amount of the potassium-containing inorganic matters satisfies the addition amount of potassium element accounting for 0.04% -5.00% of the mass of the mixture in the step (1).
Further, in the step (1), the heat treatment condition is a programmed heating heat treatment, the heating rate is 20-100 ℃/h, and the temperature is kept between 120 ℃ and 300 ℃ for 0.5-8.0 h.
Further, in the step (2), the condition of the carbonization treatment is: treating under protective gas at 250-800 deg.c, preferably 450-700 deg.c for 1-8 hr; the protective gas is inert gas and/or nitrogen, wherein the inert gas is one or more of argon and helium.
Further, in the step (2), the conditions of the steam treatment are as follows: the temperature is 150-650 ℃, the time is 2-8 h, and the preferable temperature is 350-650 ℃.
Further, in the step (3), the washing is water washing, wherein the water washing is performed by adopting a conventional means in the art, and the drying condition is that: drying for 4-10 h under the atmosphere of inert gas and/or nitrogen at 120-200 ℃.
Further, in the step (4), the microemulsion containing the active metal is prepared by mixing an active metal solution with an emulsifier. Wherein the active metal solution is a molybdenum-nickel-phosphorus solution, the content of molybdenum oxide in the solution is 20-50 g/100mL, the content of nickel oxide is 1-10 g/100mL, and the content of phosphorus is 0.1-5 g/100mL.
Further, in the step (4), the emulsifier is a nonionic emulsifier, preferably one or more selected from polyoxyethylene ether, polyoxypropylene ether, ethylene oxide and propylene oxide block copolymer, polyoxyethylene ester, polyol fatty acid ester, polyvinyl alcohol and polysorbate. The addition amount of the emulsifier is 1-20% of the volume of the active metal solution in the step (4).
Further, in the step (5), the extrusion aid is one or more selected from sesbania powder, cellulose (such as at least one of methyl cellulose and hydroxypropyl cellulose), and resin (such as at least one of phenolic resin or ethylene-vinyl acetate resin). The adding amount of the extrusion assisting agent is 0.5-10% of the mass of the carbon powder obtained in the step (3). The binder is selected from inorganic acid and/or organic acid, wherein the inorganic acid solution is nitric acid, and the organic acid solution is at least one of acetic acid, citric acid and tartaric acid. The addition amount of the binder is 0.1-15% of the mass of the carbon powder obtained in the step (3).
Further, in the step (5), the drying is performed under an inert gas and/or nitrogen atmosphere at 80-150 ℃ for 2-16 hours. The roasting conditions are as follows: roasting for 2-5 h at 300-600 ℃ under inert gas and/or nitrogen atmosphere.
In a second aspect, the present invention provides a paraffin hydrofinishing catalyst obtainable by the above synthesis process.
Further, the paraffin hydrofining catalyst comprises molybdenum oxide, nickel oxide and a carrier; wherein the mass of the molybdenum oxide is 0.1 to 28.0 percent of the mass of the catalyst, and the mass of the nickel oxide is 0.1 to 6.0 percent of the mass of the catalyst.
Further, the paraffin hydrofining catalyst also comprises phosphorus element, and the mass content of the phosphorus element is 0.1% -3.0%.
Further, the total acid amount of the paraffin hydrofining catalyst is 0.300-0.500 mmol/g.
Further, the average pore diameter of the paraffin hydrofining catalyst is 9.5-12.0 nm, preferably 9.5-10.5 nm.
The third aspect of the invention provides the application of the paraffin hydrofining catalyst in petroleum wax hydrogenation reaction.
Further, the light stability of the raw material wax petroleum wax treated in the petroleum wax hydrogenation reaction is 4-9, and the Saighur color number is more than or equal to-15.
Further, the petroleum wax hydrogenation reaction process conditions are as follows: the pressure is 2.0-10.0 MPa, the temperature is 220-320 ℃, the liquid hourly space velocity is 0.2-1.5 h -1, and the hydrogen wax volume ratio is 200-800.
Compared with the prior art, the invention has the following advantages:
(1) The method adopts the biomass raw material and the potassium salt as the carbonization raw material, and simultaneously adopts the shielding gas and the water vapor to alternately treat the carbonization raw material, thereby being beneficial to reducing the addition amount of the potassium salt in the carbon powder and ensuring that the pore diameter of the prepared carrier is easy to control.
(2) The method adopts the microemulsion containing active metal and the carbon powder to directly knead and mold to prepare the catalyst, so that the catalyst has proper surface acid property and larger pore diameter, avoids cracking reaction in the petroleum wax hydrogenation process, is used in the fields of petroleum wax hydrofining and the like, and can have good hydrofining performance.
(3) The paraffin hydrofining catalyst prepared by the method has proper surface acid property and larger pore diameter.
(4) The paraffin hydrofining catalyst prepared by the method has good paraffin hydrofining performance, the oil content of the obtained refined wax product is not obviously increased, and the Saighur color and the light stability are good.
Detailed Description
The technical scheme and effect of the present invention are further described below by examples. The embodiments and specific operation procedures are given on the premise of the technical scheme of the invention, but the protection scope of the invention is not limited to the following embodiments.
In the present invention, the total acid amount on the surface of the catalysts of the examples and comparative examples was measured by using a chemical adsorption apparatus of the American Michael type Micromeritics TriStar 2920; the pore sizes of the catalysts of the examples and comparative examples were measured using a America Michael instrument Micromeritics TriStar 2420 physical adsorption analyzer; the contents of the metal elements in the solutions and catalysts in the examples and comparative examples were analyzed by an inorganic method.
In the invention, the petroleum wax hydrogenation adopts the raw materials with light stability of 4-9 # and Saiki color number of more than or equal to-15, and adopts the national standard as the product standard, wherein the semi-refined wax product accords with the standard GB/T254-2010, and the whole refined wax product accords with the standard GB/T446-2010.
The experimental methods in the following examples, unless otherwise specified, are all conventional in the art. The experimental materials used in the examples described below, unless otherwise specified, were purchased from conventional biochemical reagent stores.
Example 1
(1) Drying oak chip raw material at 200 ℃ for 4 hours, and then crushing into 300-mesh oak chip powder; respectively weighing 1000g of oak dust powder and 5g of potassium hydroxide for mixing; then the mixture is heated to 250 ℃ at the heating rate of 50 ℃/h, and is subjected to heat treatment for 2h at 250 ℃; then carbonizing for 4 hours in inert atmosphere at 500 ℃, then carrying out steam treatment on the carbonized material for 1 hour at 500 ℃, and repeating the carbonization and steam treatment for 2 times, namely carrying out the carbonization and steam treatment steps for 3 times respectively, so as to obtain an intermediate; the obtained intermediate was subjected to water purification washing treatment and then dried at 100℃for 4 hours under an inert atmosphere to obtain 483g of carbon powder.
(2) Preparing a molybdenum-nickel-phosphorus solution, wherein the content of molybdenum oxide in the solution is 36.4g/100mL, the content of nickel oxide is 7.6g/100mL, and the content of phosphorus is 3.8g/100mL. A microemulsion containing active metal was prepared by adding 35g of polysorbate 80 to 483mL of the molybdenum nickel phosphorus solution. 483g of carbon powder is mixed with the microemulsion, 10g of sesbania powder, 20g of methyl cellulose and 10g of nitric acid are added, kneaded, dried for 5 hours at 110 ℃ in nitrogen atmosphere, and then baked for 3 hours at 450 ℃ in nitrogen atmosphere, so that the paraffin hydrofining catalyst A is prepared. The physicochemical properties of the catalyst of example 1 above are listed in table 1.
Example 2
The paraffin hydrorefining catalyst B of the present invention was prepared under the same conditions as in example 1 except that 1000g of coffee grounds powder was weighed instead of 1000g of oak dust powder. The physicochemical properties of the catalyst are shown in Table 1.
Example 3
The paraffin hydrorefining catalyst C of the present invention was prepared as in example 1, except that the carbonization temperature was 550℃and the other conditions were unchanged. The physicochemical properties of the catalyst are shown in Table 1.
Example 4
The paraffin hydrorefining catalyst D of the present invention was prepared as in example 1 except that carbon powder was mixed with the microemulsion, and kneading was performed by using 15g of hydroxypropyl cellulose instead of 20g of methylcellulose, and molding was performed under the same conditions. The physicochemical properties of the catalyst are shown in Table 1.
Example 5
The same procedure as in example 1 was followed except that 20g of polysorbate 80 was used to prepare a microemulsion of molybdenum nickel phosphorus solution, under otherwise unchanged conditions, to prepare the paraffin hydrofining catalyst E of the present invention. The physicochemical properties of the catalyst are shown in Table 1.
Comparative example 1
The industrial pseudo-boehmite, 2wt% nitric acid and 2wt% sesbania powder, the microemulsion containing active metal in example 1 were mixed, molded, dried at 120℃for 4 hours, and calcined at 450℃for 3 hours to prepare a paraffin hydrofining catalyst F. The physicochemical properties of the catalyst are shown in Table 1.
Comparative example 2
The technical grade pseudo-boehmite, 2wt% nitric acid and 2wt% sesbania powder are mixed, molded, dried at 130 ℃ for 3 hours and baked at 700 ℃ for 3 hours to prepare an alumina carrier (carrier liquid absorption rate is 0.84), the carrier is saturated and immersed into an impregnating solution containing molybdenum and nickel (wherein the content of the molybdenum oxide is 45.2G/100mL, the content of the nickel oxide is 9.5G/100mL, and the content of the phosphorus is 4.8G/100 mL), and the carrier is dried at 120 ℃ for 5 hours and then baked at 450 ℃ for 3 hours to prepare the paraffin hydrofining catalyst G.
Comparative example 3
(1) Drying oak chip raw material at 200 ℃ for 4 hours, and then crushing into 300-mesh oak chip powder; respectively weighing 1000g of oak dust powder and 5g of potassium hydroxide for mixing; then the mixture is heated to 250 ℃ at the heating rate of 50 ℃/h, and is subjected to heat treatment for 2h at 250 ℃; then carbonizing for 4 hours in inert atmosphere at the carbonization temperature of 500 ℃ to prepare an intermediate; the obtained intermediate was subjected to water purification washing treatment and then dried at 100℃for 4 hours under an inert atmosphere to obtain 483g of carbon powder.
(2) Preparing a molybdenum-nickel-phosphorus solution, wherein the content of molybdenum oxide in the solution is 38g/100mL, the content of nickel oxide is 8.0g/100mL, and the content of phosphorus is 4.0g/100mL. A microemulsion containing active metal was prepared by adding 35g of polysorbate 80 to 483mL of the molybdenum nickel phosphorus solution. 483g of carbon powder is mixed with the microemulsion, 10g of sesbania powder, 20g of methyl cellulose and 10g of nitric acid are added, kneaded, dried for 5 hours at 110 ℃ in nitrogen atmosphere, and then baked for 3 hours at 450 ℃ in nitrogen atmosphere, thus preparing the paraffin hydrofining catalyst H.
The physicochemical properties of the catalysts obtained in the above examples and comparative examples are listed in table 1.
Table 1 properties of the catalysts obtained in examples and comparative examples
Catalyst numbering |
A |
B |
C |
D |
E |
F |
G |
H |
Specific surface area, m 2/g |
235 |
239 |
228 |
236 |
234 |
182 |
167 |
174 |
Pore volume, mL/g |
0.51 |
0.52 |
0.55 |
0.52 |
0.51 |
0.28 |
0.39 |
0.24 |
Average pore diameter, nm |
9.75 |
9.83 |
10.31 |
9.84 |
9.71 |
7.18 |
8.48 |
6.64 |
Total acid, mmol/g |
0.369 |
0.376 |
0.332 |
0.373 |
0.347 |
0.678 |
0.568 |
0.358 |
MoO3,wt% |
24.51 |
23.78 |
24.49 |
24.53 |
24.52 |
24.38 |
24.48 |
24.48 |
NiO,wt% |
5.15 |
5.08 |
5.14 |
5.17 |
5.15 |
5.08 |
5.14 |
5.12 |
P,wt% |
2.50 |
2.46 |
2.47 |
2.48 |
2.45 |
2.44 |
2.56 |
2.46 |
Example 6
The paraffin wax hydrofining catalysts prepared in the above examples 1-5 and comparative examples 1,2 and 3 were used to hydrofining raw material wax under the same process conditions of 5.0MPa, 260 ℃ and 1.0h -1 of liquid hourly space velocity, 500 of hydrogen wax volume ratio, and the properties of the raw material wax and hydrofined wax products are listed in Table 2.
Table 2 raw wax and hydrofinishing product properties for each example and comparative example
As can be seen from Table 2, the paraffin hydrofining catalyst prepared by the method of the invention has no oil content rise in the paraffin product after hydrofining, and the Sai color number of the obtained paraffin product is more than or equal to +30, which indicates that the paraffin hydrofining catalyst prepared by the method of the invention has excellent hydrofining performance and good quality of the paraffin product after hydrofining.