CN112675872A - Hydrogenation catalyst before deethanization before carbon dioxide fraction - Google Patents
Hydrogenation catalyst before deethanization before carbon dioxide fraction Download PDFInfo
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Abstract
The invention relates to a selective hydrogenation catalyst, in particular to a hydrogenation catalyst before deethanization before carbon dioxide fraction removal, wherein a carrier is alumina or mainly alumina, the carrier has a bimodal pore distribution structure, and the specific surface area of the catalyst is 4-12 m2(ii) in terms of/g. Wherein the aperture of the small hole is 55-72nm, and the aperture of the large hole is 300-640 nm. The catalyst at least contains Pd, Ni and Cu, wherein the Pd and the Ni are loaded in a microemulsion mode and a solution mode, and the Cu is loaded in a microemulsion mode. The catalyst comprises, by mass, 100%, 0.03-0.04% of solution-supported Pd, 2.5-3.5% of solution-supported Ni and 1.0-4.5% of microemulsion-supported Ni, 0.1-1.0% of microemulsion-supported Ni and 1/250-1/400% of microemulsion-supported Pd. By adopting the inventionThe catalyst has lower reduction temperature, low green oil generation amount and excellent catalytic performance and coking resistance.
Description
Technical Field
The invention relates to an alkyne selective hydrogenation catalyst, in particular to a high-coking-resistance selective hydrogenation catalyst for hydrogenation before deethanization before carbon dioxide fraction.
Background
Ethylene is one of the most important basic raw materials for the petrochemical industry, and is produced by steam cracking of petroleum hydrocarbons (e.g., ethane, propane, butane, naphtha, light diesel, etc.) as a monomer-ethylene for synthesizing various polymers. The C2 fraction mainly containing ethylene obtained by the method also contains 0.5 to 2.5 percent (mole fraction) of acetylene. The presence of acetylene complicates the polymerization process of ethylene and deteriorates the polymer properties. When polyethylene is produced by a high pressure process, there is a risk of explosion due to the accumulation of acetylene; in addition, the presence of acetylene also reduces the activity of the polymerization catalyst and increases the catalyst consumption when producing polyethylene. Therefore, acetylene in ethylene must be reduced to a certain value or less to be used as a monomer for synthesizing a high polymer.
Ethylene plants are divided into two processes according to the difference of the separation flow: a hydrogenation alkyne-removing process after carbon dioxide and a hydrogenation alkyne-removing process before carbon dioxide. In the hydrogenation process before carbon dioxide, a hydrogenation reactor is positioned in front of a demethanizer, then the hydrogenation adopts a sequential separation process, the hydrogenation reaction is carried out after methane and ethane are removed, and the hydrogenation reactor is positioned behind the demethanizer. The post-hydrogenation process is mainly represented by a sequential separation process technology of the LUMMUS company, and the process flow is common in ethylene devices introduced at early stage in China. The front hydrogenation process is divided into front deethanization front hydrogenation and front depropanization front hydrogenation, which are developed by LINDE company and S & W company respectively, acetylene is removed by selective hydrogenation before a demethanizer in the two processes, but in the front depropanization front hydrogenation process, the material entering a hydrogenation reactor not only has C2 fraction but also part of C3 fraction, and most of propyne and propadiene need to be removed while acetylene is removed.
The principle of selective hydrogenation and alkyne removal by carbon:
main reaction: c2H2+H2→C2H4+174.3kJ/mol (1)
CH3-C≡CH+H2→C3H6+165kJ/mol (2)
H2C＝C＝CH2+H2→C3H6+173kJ/mol (3)
Side reaction: c2H2+2H2→C2H6+311.0kJ/mol (4)
C2H4+H2→C2H6+136.7kJ/mol (5)
C3H6+H2→C3H8+136.7kJ/mol (6)
nC2H2→ oligomer (Green oil) (7)
Of these, reactions (1) and (2) are the desired primary reactions, removing both acetylene, propyne and propadiene, and increasing ethylene and propylene yields. (3) The compounds of formulae (4), (5), (6) and (7) are undesirable side reactions, resulting in loss of ethylene and propylene. A side reaction (7), wherein acetylene is subjected to a hydrodimerization reaction to generate a carbon four fraction; polymerizing the C-C fraction to generate oligomer with wider molecular weight, commonly called green oil; the green oil adsorbs on the catalyst surface, eventually forming coke. The coke blocks the catalyst pore channels, so that reactants cannot diffuse to the surface of the active center of the catalyst, thereby causing the activity of the catalyst to be reduced and influencing the operation period and the service life of the catalyst.
The patent US4404124 prepares a selective hydrogenation catalyst with a palladium shell layer distribution as an active component by a step impregnation method, and can be applied to selective hydrogenation of carbon dioxide and carbon three fractions to eliminate acetylene in ethylene and propyne and propadiene in propylene. US5587348 uses alumina as carrier, regulates the action of promoter silver and palladium, and adds alkali metal and chemically bonded fluorine to prepare excellent carbon dioxide hydrogenation catalyst. The catalyst has the characteristics of reducing the generation of green oil, improving the selectivity of ethylene and reducing the generation amount of oxygen-containing compounds. US5519566 discloses a process for preparing silver and palladium catalysts by wet reduction, by adding organic or inorganic reducing agents to the impregnation solution, silver and palladium bi-component selective hydrogenation catalysts are prepared.
The traditional carbon dioxide hydrogenation catalyst is prepared by adopting an impregnation method, and the active phase of the catalyst is Pd and Ag bimetal. This method has the following disadvantages: (1) under the influence of the carrier pore structure, the dispersion of the active components can not be accurately controlled, and the randomness is strong. (2) Under the influence of the surface tension and solvation effect of the impregnation liquid, the precursor of the metal active component is deposited on the surface of the carrier in an aggregate form and cannot be uniformly distributed. (3) The carbon hydrogenation has higher requirement on the selectivity of the catalyst, and the traditional preparation method promotes the function of the auxiliary agent by increasing the amount of Ag, so that the transfer of hydrogen is hindered, the possibility of oligomerization is increased, the green oil generation amount is increased, and the service life of the catalyst is influenced. The three phenomena easily cause poor dispersibility of the metal active component, low reaction selectivity and high green oil generation amount, thereby influencing the overall performance of the catalyst.
CN201110086174.0 forms a polymer coating layer on the surface of the carrier in a certain thickness by adsorbing a specific polymer compound on the carrier, and the compound with a functional group reacts with the polymer to enable the polymer to have the functional group capable of complexing with the active component, and the active component is ensured to be orderly and highly dispersed by the complexing reaction of the active component on the functional group on the surface of the carrier. By adopting the method, the carrier adsorbs specific high molecular compounds, and chemical adsorption is carried out on the high molecular compounds and the hydroxyl groups of the alumina, so that the amount of the high molecular compounds adsorbed by the carrier is limited by the number of the hydroxyl groups of the alumina; the functional polymer and Pd have weak complexing effect, sometimes the loading capacity of the active component can not meet the requirement, and part of the active component remains in the impregnation liquid, so that the cost of the catalyst is increased.
In order to improve the anti-coking performance of the catalyst and reduce the surface coking degree of the catalyst, a carbon dioxide selective hydrogenation catalyst which adopts a bimodal pore carrier and a microemulsion preparation method to load active components and a preparation method thereof are disclosed in recent years. The selective hydrogenation catalyst disclosed in patent ZL201310114077.7 has a carrier which is mainly alumina and has a bimodal pore distribution structure, wherein the pore diameter of a small pore is 55-72nm, and the pore diameter of a large pore is 60-800 nm. The catalyst contains 0.01-0.5 wt% of Pd based on 100% of the mass of the catalyst, is distributed as a shell layer, and has a thickness of 1-500 um; 0.2-5 wt% of Ni, and the particle size of the anti-coking component Ni is controlled to be larger than that of the small holes of the carrier by a microemulsion method, so that Ni is mainly distributed in the large holes of the carrier. Patent ZL201310114079.6 discloses a method for preparing a hydrogenation catalyst, wherein the catalyst carrier is mainly alumina and has a bimodal pore distribution structure. The catalyst contains Pd and Ni double active components, wherein the anti-coking component Ni enters the macropores of the carrier in a form of microemulsion when the catalyst is prepared, and the active component Pd is mainly distributed on the surface of the carrier, particularly in the micropores. Patent ZL201310114371.8 discloses a selective hydrogenation process for carbon-containing fractions suitable for use in a pre-depropanization pre-hydrogenation process. The selective hydrogenation catalyst adopted by the method has a carrier of alumina or mainly alumina, and has a bimodal pore distribution structure, contains double active components Pd and Ni, and an anti-coking component Ni is mainly distributed in macropores. The method improves the coking resistance of the catalyst, but the reduction temperature of the single-component Ni in the macropores of the catalyst carrier reaches over 500 ℃, and the catalyst is reduced at the temperature, so that the active component Pd of the catalyst is gathered, and the activity of the catalyst is greatly reduced. In order to compensate for the loss of catalyst activity, the amount of active component is increased, which results in a decrease in catalyst selectivity and a decrease in the utilization of active component.
Disclosure of Invention
The invention relates to an alkyne selective hydrogenation catalyst, in particular to a high-coking-resistance selective hydrogenation catalyst for hydrogenation before deethanization before carbon dioxide fraction.
An alkyne selective hydrogenation catalyst is characterized in that a carrier is alumina or mainly alumina and has a bimodal pore distribution structure, wherein the pore diameter of a small pore is 55-72nm, and the pore diameter of a large pore is 300-640 nm. The specific surface area of the catalyst is 4-12 m2/g。
In the catalyst, the catalyst at least contains Pd, Ni and Cu, wherein the Pd and the Ni are loaded in a micro-emulsion mode and a solution mode, and the Cu is loaded in the micro-emulsion mode. The catalyst comprises, by mass, 100%, 0.03-0.04% of solution-supported Pd, preferably 0.032-0.035%, 2.5-3.5% of solution-supported Ni and 2.6-3.2% of solution-supported Pd by weight, 1.0-4.5% of microemulsion-supported Ni, preferably 1.5-3.0% of microemulsion-supported Ni by weight, 0.1-1.0% of Cu and 0.3-0.7% of microemulsion-supported Ni by weight, and 1/250-1/400% of microemulsion-supported Ni + Cu by weight, preferably 1/300-1/350% of microemulsion-supported Pd. Wherein the microemulsion-supported Ni, Cu and Pd are mainly distributed in macropores of 300-640 nm of the carrier.
In the catalyst, the selective hydrogenation reaction of acetylene takes place in the main active center composed of Pd and Ni, Ni and Cu are immersed in the macropores of the carrier in the form of microemulsion, and the green oil generated in the reaction is subjected to saturated hydrogenation on the active center composed of Cu and Ni.
For hydrogenation reaction, generally, before the catalyst is applied, the hydrogenation catalyst needs to be reduced first to ensure that the active component exists in a metallic state, so that the catalyst can have hydrogenation activity. Because activation is a high temperature calcination process during catalyst preparation, the metal salt decomposes to metal oxides, which form clusters, which are typically nano-sized. Different oxides need to be reduced at different temperatures due to different chemical properties. However, for nano-sized metals, a critical temperature is around 200 ℃, and above this temperature, the aggregation of metal particles is very significant. Therefore, the reduction temperature of the active component is very important for the hydrogenation catalyst.
The idea of the invention for solving the problem of catalyst coking is as follows:
the alkyne selective hydrogenation reaction occurs in the main active center of the composition, such as Pd and Ni, and macromolecules such as green oil produced in the reaction easily enter the macropores of the catalyst. In the macropores of the catalyst, a Ni/Cu component is loaded, wherein Ni has a saturation hydrogenation function, and the green oil component can perform a saturation hydrogenation reaction at an active center consisting of Ni/Cu. Because the double bonds are saturated by hydrogenation, the green oil component can not generate polymerization reaction any more or the polymerization reaction rate is greatly reduced, the chain growth reaction is terminated or delayed, a fused ring compound with huge molecular weight can not be formed, and the fused ring compound is easily carried out of the reactor by materials, so the coking degree on the surface of the catalyst is greatly reduced, and the service life of the catalyst is greatly prolonged.
The method for controlling the Ni/Cu alloy to be positioned in the catalyst macropores is that Ni/Cu is loaded in the form of microemulsion, and the grain diameter of the microemulsion is larger than the pore diameter of carrier micropores and smaller than the maximum pore diameter of macropores. The nickel and copper metal salts are contained in the microemulsion and, due to steric resistance, are difficult to access to the smaller size pores of the support and therefore mainly to the macropores of the support.
In the invention, Cu and Ni are loaded together, so that the reduction temperature of Ni can be reduced, because NiO is required to be completely reduced independently, the reduction temperature is generally 450-500 ℃, Pd agglomeration can be caused at the temperature, and after the Cu/Ni alloy is formed, the reduction temperature can be reduced by more than 100 ℃ and reaches 350 ℃ compared with the reduction temperature of pure Ni, so that the Pd agglomeration in the reduction process is relieved.
In the invention, a small amount of Pd supported by the microemulsion is on the surface of the Ni/Cu alloy, so that the reduction temperature of Ni can be further reduced to below 200 ℃ and as low as 150 ℃.
In the invention, in the process of loading palladium by the solution method, the solution containing palladium enters the pores more quickly due to the siphonage action of the pores, the palladium exists in the form of chloropalladate ions, and the ions can form chemical bonds with hydroxyl on the surface of the carrier to target the palladium quickly, so that the faster the solution enters the pore channels, the faster the loading speed. Therefore, the catalyst is more easily supported in the pores during the impregnation of Pd by the solution method.
In the invention, the Pd is loaded by adopting a solution method and a microemulsion method, namely, most of the Pd is loaded by adopting a solution, and the Pd solution is recommended to adopt a supersaturated impregnation method; a small part of Pd is loaded in a microemulsion mode, the particle size of the microemulsion is controlled to be larger than 72nm and smaller than 640nm when the Pd is loaded in the microemulsion mode, so that the part of Pd is distributed in macropores of the carrier, and the step of loading Pd by the microemulsion is after the step of loading Ni and Cu by the microemulsion.
In the invention, the carrier is required to have a bimodal pore distribution structure, the pore diameter of a large pore is 300-640 nm, and the pore diameter of a small pore is 55-72 nm. The carrier is alumina or mainly alumina, Al2O3The crystal form is preferably alpha, theta or a mixed crystal form thereof. The alumina content in the catalyst carrier is preferably above 80%, and the carrier may also contain other metal oxides such as magnesia, titania, etc.
In the present invention, the supporting of Ni by the solution method may be performed by a solution supersaturated impregnation method, and the supporting thereof is performed after Pd is supported by the solution.
The invention is not particularly limited in the process of loading Ni, Cu and Pd in a microemulsion manner, and Ni, Cu and Pd can be distributed in macropores of the carrier as long as the particle size of the microemulsion with the particle size of more than 72nm and less than 640nm can be formed.
In the invention, the weight ratio of the water phase to the oil phase is 4.0-5.0, the weight ratio of the surfactant to the oil phase is 0.10-0.40, and the weight ratio of the surfactant to the cosurfactant is 1-1.2.
The invention also provides a more specific catalyst, and a preparation method of the catalyst comprises the following steps:
(1) dissolving precursor salts of Ni and Cu in water, adding an oil phase, a surfactant and a cosurfactant, fully stirring to form a microemulsion, and controlling the particle size of the microemulsion to be more than 72nm and less than 640 nm; adding the carrier into the prepared microemulsion, dipping for 0.5-4 hours, filtering out residual liquid, drying for 1-6 hours at 80-120 ℃, and roasting for 2-8 hours at 300-600 ℃. Obtaining a semi-finished product catalyst A;
(2) dissolving a precursor salt of Pd in water, adjusting the pH value to 1.5-2.5, adding the semi-finished catalyst A into a Pd salt solution, soaking and adsorbing for 0.5-4 h, drying at 80-120 ℃ for 1-4 h, and roasting at 400-550 ℃ for 2-6 h to obtain a semi-finished catalyst B;
(3) the Ni loading by the solution method is carried out by a supersaturated impregnation method, namely, the prepared Ni salt solution is 80-110% of the saturated water absorption of the carrier, the pH value is adjusted to be 1-5, and the semi-finished catalyst B is roasted at 500-550 ℃ for 4-6 hours after being loaded with Ni to obtain a semi-finished catalyst C;
(4) dissolving Pd precursor salt in water, adding an oil phase, a surfactant and a cosurfactant, fully stirring to form a microemulsion, and controlling the particle size of the microemulsion to be larger than 72nm and smaller than 640 nm; adding the semi-finished catalyst C into the prepared microemulsion, dipping for 0.5-4 hours, and filtering out residual liquid; drying at 80-120 ℃ for 1-6 hours, and roasting at 300-600 ℃ for 2-8 hours to obtain the catalyst.
In the above preparation steps, step (1) and step (2) may be interchanged, step (3) following step (2), and step (4) following step (1).
The carrier in the step (1) can be spherical, cylindrical, clover-shaped, dentate spherical, clover-shaped and the like.
The precursor salts of Ni, Cu and Pd in the above steps are soluble salts, and can be nitrates, chlorides or other soluble salts thereof.
The reduction temperature of the catalyst of the invention is preferably 150 to 200 ℃.
The catalyst had the following characteristics: at the beginning of the hydrogenation reaction, the hydrogenation activity of palladium is high and is mainly distributed in the pores, so that the selective hydrogenation reaction of acetylene mainly occurs in the pores. With the prolonging of the operation time of the catalyst, a part of by-products with larger molecular weight are generated on the surface of the catalyst, and due to the larger molecular size, the substances enter the macropores more frequently and the retention time is longer, the hydrogenation reaction of double bonds can be generated under the action of the nickel catalyst, so that saturated hydrocarbon or aromatic hydrocarbon without isolated double bonds is generated, and substances with larger molecular weight are not generated any more.
The catalyst can greatly reduce the reduction temperature of the catalyst to 150-200 ℃ at the lowest, and reduce the agglomeration of active components in the reduction process.
The catalyst of the invention has greatly increased green oil generation amount even if the raw material contains more heavy fractions, and the activity and the selectivity of the catalyst still have no trend of reduction.
Drawings
FIG. 1 is a graph showing the distribution of the reduction temperature peaks of Ni/Cu in example 1.
FIG. 2 is a flow diagram of a hydrogenation acetylene removal process prior to deethanization before carbon two.
Wherein, the reference numbers:
1-oil washing tower
2-water washing tower
3-alkaline washing tower
4-drying tower
5-front deethanizer
6-carbon two hydrogenation reactor
7-demethanizer
Detailed Description
The following examples illustrate the invention in detail: the present example is carried out on the premise of the technical scheme of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following examples, and the experimental methods without specific conditions noted in the following examples are generally performed according to conventional conditions.
The analysis and test method comprises the following steps:
comparison table: GB/T-5816;
pore volume: GB/T-5816;
the content of active components in the catalyst is as follows: atomic absorption method;
microemulsion particle size distribution of Ni/Cu alloy: a dynamic light scattering particle size analyzer, which is used for analyzing on an M286572 dynamic light scattering analyzer;
the conversion and selectivity in the examples were calculated according to the following formulas:
acetylene conversion (%). 100. times. delta. acetylene/inlet acetylene content
Ethylene selectivity (%). 100 x. DELTA. ethylene/. DELTA.acetylene
Example 1
Carrier: a commercially available spherical alumina carrier with bimodal pore distribution and a diameter of 4mm is adopted, and 100g of the spherical alumina carrier is weighed after being calcined at high temperature for 4 hours. The calcination temperature and the physical index of the carrier are shown in Table 1.
Preparing a catalyst:
(1) weighing a certain amount of nickel nitrate, dissolving copper chloride in deionized water, adding a certain amount of cyclohexane, Triton X-100 and n-butanol, fully stirring to form a microemulsion, soaking 100g of the weighed carrier into the prepared microemulsion for 1 hour, washing the carrier to be neutral by using the deionized water, drying the carrier for 2 hours at 120 ℃, and roasting the carrier for 5 hours at 550 ℃. Obtaining a semi-finished product catalyst A.
(2) Weighing a certain amount of palladium nitrate, dissolving in deionized water, adjusting the pH value to 1, adding the semi-finished catalyst A into the solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain a semi-finished catalyst B.
(3) Weighing nickel nitrate, preparing into a solution by using deionized water, soaking the semi-finished catalyst B into the solution, drying the semi-finished catalyst B for 3 hours at 110 ℃ after the solution is completely absorbed, and roasting the semi-finished catalyst B for 4 hours at 500 ℃ to obtain the required catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at 350 ℃ for 12 h.
Example 2
Carrier: a commercially available spherical carrier with bimodal pore distribution and a diameter of 4mm is adopted, and the composition of the carrier is 90% of alumina and 10% of titanium oxide. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes of the carrier are shown in Table 1.
Preparing a catalyst:
(1) weighing a certain mass of nickel nitrate, dissolving copper chloride in deionized water, adding a certain amount of cyclohexane, TritonX-100 and n-hexanol, and fully stirring to form microemulsion. The carrier is added into the prepared microemulsion for dipping for 1 hour, washed to be neutral by deionized water, dried for 2 hours at 120 ℃ and roasted for 5 hours at 550 ℃. Obtaining a semi-finished product catalyst A.
(2) Weighing a certain amount of palladium nitrate, dissolving the palladium nitrate in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. And adding the semi-finished catalyst A into the prepared microemulsion, soaking for 4 hours, washing to be neutral by using deionized water, drying for 4 hours at 90 ℃, and roasting for 2 hours at 600 ℃ to obtain a semi-finished catalyst B.
(3) Weighing a certain amount of palladium nitrate salt, dissolving in water, adjusting the pH value to 2, adding the semi-finished product B into a Pd salt solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain a semi-finished product catalyst C.
(4) Weighing a certain amount of nickel nitrate, dissolving the nickel nitrate in deionized water, soaking the semi-finished catalyst C in the prepared solution, drying the semi-finished catalyst C for 3 hours at 110 ℃, and roasting the semi-finished catalyst C for 4 hours at 500 ℃ to obtain the finished catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at 300 ℃ for 12h under the condition of 1: 1.
Example 3
Carrier: a commercially available spherical alumina carrier with bimodal pore distribution and a diameter of 4mm was used. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes are shown in table 1.
Preparing a catalyst:
(1) weighing a certain amount of palladium nitrate salt, dissolving in water, adjusting the pH value to 2, adding the carrier into a Pd salt solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain a semi-finished catalyst A.
(2) Weighing a certain amount of nickel nitrate, dissolving the nickel nitrate in deionized water, soaking the semi-finished catalyst A in the prepared solution, drying the semi-finished catalyst A for 3 hours at 110 ℃, and roasting the semi-finished catalyst A for 4 hours at 500 ℃ to obtain a semi-finished catalyst B.
(3) Weighing a certain amount of nickel nitrate and copper chloride, dissolving in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. Adding the semi-finished catalyst B into the prepared microemulsion, soaking for 4 hours, washing to be neutral by deionized water, drying for 4 hours at 90 ℃, and roasting for 2 hours at 600 ℃. Obtaining a semi-finished product catalyst C.
(4) Weighing a certain amount of palladium nitrate, dissolving the palladium nitrate in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. Adding the semi-finished catalyst C into the prepared microemulsion, soaking for 4 hours, washing to be neutral by deionized water, drying for 4 hours at 90 ℃, and roasting for 2 hours at 600 ℃. And obtaining the finished catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at the temperature of 160 ℃ for 12h under the condition of 1: 1.
Example 4
Carrier: a commercially available spherical alumina carrier with bimodal pore distribution and a diameter of 4mm was used. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes are shown in table 1.
Preparing a catalyst:
(1) weighing a certain amount of nickel nitrate and copper chloride, dissolving in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. The carrier is added into the prepared microemulsion for dipping for 4 hours, then is washed to be neutral by deionized water, is dried for 4 hours at the temperature of 90 ℃, and is roasted for 2 hours at the temperature of 600 ℃. Obtaining a semi-finished product catalyst A.
(2) Weighing a certain amount of palladium nitrate salt, dissolving in water, adjusting the pH value to 2, adding the semi-finished catalyst A into a Pd salt solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain a semi-finished catalyst B.
(3) Weighing a certain amount of nickel nitrate, dissolving the nickel nitrate in deionized water, soaking the semi-finished catalyst B in the prepared solution, drying the semi-finished catalyst B for 3 hours at 110 ℃, and roasting the semi-finished catalyst B for 4 hours at 500 ℃ to obtain a semi-finished catalyst C.
(4) Weighing a certain amount of palladium nitrate, dissolving the palladium nitrate in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. Adding the semi-finished catalyst C into the prepared microemulsion, soaking for 4 hours, washing to be neutral by deionized water, drying for 4 hours at 90 ℃, and roasting for 2 hours at 600 ℃. And obtaining the finished catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at the temperature of 170 ℃ for 12h under the condition of 1: 1.
Example 5
Carrier: a commercially available spherical alumina carrier with bimodal pore distribution and a diameter of 4mm was used. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes are shown in table 1.
Preparing a catalyst:
(1) weighing a certain amount of nickel nitrate and copper chloride, dissolving in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. The carrier is added into the prepared microemulsion for dipping for 4 hours, then is washed to be neutral by deionized water, is dried for 4 hours at the temperature of 90 ℃, and is roasted for 2 hours at the temperature of 600 ℃. Obtaining a semi-finished product catalyst A.
(2) Weighing a certain amount of palladium nitrate, dissolving the palladium nitrate in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. Adding the semi-finished catalyst A into the prepared microemulsion, soaking for 4 hours, washing to be neutral by deionized water, drying for 4 hours at 90 ℃, and roasting for 2 hours at 600 ℃. Obtaining a semi-finished product catalyst B.
(3) Weighing a certain amount of palladium nitrate salt, dissolving in water, adjusting the pH value to 2, adding the semi-finished catalyst B into a Pd salt solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain a semi-finished catalyst C.
(4) Weighing a certain amount of nickel nitrate, dissolving the nickel nitrate in deionized water, soaking the semi-finished catalyst C in the prepared solution, drying the semi-finished catalyst C for 3 hours at 110 ℃, and roasting the semi-finished catalyst C for 4 hours at 500 ℃ to obtain the finished catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at 150 ℃ for 12h under the condition of 1: 1.
Comparative example 1
Carrier: a commercially available spherical alumina carrier with bimodal pore distribution and a diameter of 4mm was used. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes are shown in table 1.
Preparing a catalyst:
(1) weighing a certain amount of nickel nitrate, dissolving the nickel nitrate in 70ml of deionized water, adding a certain amount of cyclohexane, Triton X-100 and n-butanol, fully stirring to form a microemulsion, dipping the carrier into the prepared microemulsion, washing the carrier to be neutral by using the deionized water after dipping for 1 hour, drying the carrier for 2 hours at 120 ℃, and roasting the carrier for 5 hours at 550 ℃. A semi-finished catalyst A1 was obtained.
(2) Weighing a certain amount of palladium nitrate, dissolving in deionized water, adjusting the pH value to 1, then soaking the semi-finished catalyst A into the prepared Pd salt solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain a semi-finished catalyst B1.
(3) Weighing nickel nitrate, preparing a solution by using deionized water, soaking the semi-finished catalyst B1 in the solution, drying the solution for 3 hours at 110 ℃ after the solution is completely absorbed, and roasting the solution for 4 hours at 500 ℃ to obtain the required catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at 350 ℃ for 12 h.
Comparative example 2
Carrier: a commercially available spherical carrier with bimodal pore distribution and a diameter of 4mm is adopted, and the composition of the carrier is 90% of alumina and 10% of titanium oxide. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes are shown in table 1.
Preparing a catalyst:
(1) weighing a certain amount of nickel nitrate, dissolving copper nitrate in deionized water, adding a certain amount of cyclohexane, 14.3g of Triton X-100 and 13.60g of n-hexanol, and fully stirring to form microemulsion. The carrier is added into the prepared microemulsion for dipping for 1 hour, washed to be neutral by deionized water, dried for 2 hours at 120 ℃ and roasted for 5 hours at 550 ℃. A semi-finished catalyst A1 was obtained.
(2) Weighing a certain amount of palladium nitrate salt, dissolving in water, adjusting the pH value to 2, adding the semi-finished catalyst A1 into a Pd salt solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain the finished catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at 350 ℃ for 12 h.
Comparative example 3
Carrier: a commercially available spherical alumina support with monomodal pore distribution and a diameter of 4mm was used. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes are shown in table 1.
Preparing a catalyst:
(1) weighing a certain amount of palladium chloride salt, dissolving in water, adjusting the pH value to 3, adding the weighed carrier into a Pd salt solution, soaking and adsorbing for 2h, drying at 120 ℃ for 1h, and roasting at 450 ℃ for 4h to obtain a semi-finished catalyst A1.
(2) Weighing a certain amount of nickel nitrate, dissolving the nickel nitrate in deionized water, soaking the semi-finished catalyst A1 in the prepared solution, drying the solution for 4 hours at 100 ℃ after the solution is completely absorbed, and roasting the solution for 6 hours at 400 ℃ to obtain the required catalyst.
The contents of the components in the catalyst are shown in Table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at 350 ℃ for 12 h.
Comparative example 4
Carrier: a commercially available spherical alumina carrier with bimodal pore distribution and a diameter of 4mm was used. After high-temperature roasting for 4 hours, 100g of the carrier is weighed, and the physical indexes are shown in table 1.
Preparing a catalyst:
(1) weighing a certain amount of palladium nitrate salt, dissolving in water, adjusting the pH value to 2, adding the carrier into a Pd salt solution, soaking and adsorbing for 1h, drying for 2h at 110 ℃, and roasting for 6h at 380 ℃ to obtain a semi-finished catalyst A.
(2) Weighing a certain amount of nickel nitrate, dissolving the nickel nitrate in deionized water, adding the semi-finished catalyst A into the prepared solution, drying the mixture for 3 hours at 110 ℃, and roasting the mixture for 4 hours at 500 ℃ to obtain a semi-finished catalyst B.
(3) Weighing a certain amount of nickel nitrate and ferric chloride, dissolving in water, adding a certain amount of cyclohexane and TritonX-100, and fully stirring 6.03g of n-hexanol to form microemulsion. Adding the semi-finished catalyst B into the prepared microemulsion, soaking for 4 hours, washing to be neutral by deionized water, drying for 4 hours at 90 ℃, and roasting for 2 hours at 600 ℃. And obtaining the finished catalyst.
The particle size of the microemulsion prepared in the catalyst preparation process and the content of each component in the catalyst are shown in table 2.
Before use, the mixture is placed in a fixed bed reaction device and is mixed with N2:H2Reducing the mixed gas at the temperature of 160 ℃ for 12h under the condition of 1: 1.
Table 1 physical properties of catalyst supports in examples and comparative examples
TABLE 2 content of active components of catalysts in examples and comparative examples
The performance of the catalyst is evaluated in a fixed bed single-stage reactor. Reaction conditions are as follows: space velocity of 13000h-1The pressure is 3.5 MPa. The reaction mass composition is shown in Table 3.
TABLE 3 reaction Material composition
| Hydrogenation raw material | H2 | C2H2 | C2H4 | C2H6 | CH4 | CO |
| Content (phi%) | 17.2 | 0.65 | 41.6 | 8.5 | 32.0 | 0.08 |
The catalyst evaluation results are shown in Table 4. Catalysts 1, 2, 3, 4, 5 were from examples 1, 2, 3, 4, 5, respectively; comparative examples 1, 2, 3, 4 were derived from comparative examples 1, 2, 3, 4, respectively.
TABLE 4 catalyst evaluation results
The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (12)
1. A hydrogenation catalyst before deethanization before carbon dioxide fraction separation, wherein a carrier is alumina or mainly alumina, the catalyst has a bimodal pore distribution structure, and the specific surface area of the catalyst is 4-12 m2The catalyst at least contains Pd, Ni and Cu, wherein the Pd and the Ni are loaded in a microemulsion mode and a solution mode, the Cu is loaded in a microemulsion mode, the weight ratio of the solution loaded Ni to the solution loaded Pd is 2.5-3.5, preferably 2.6-3.2, the weight ratio of the solution loaded Ni to the solution loaded Pd is 2.5-3.5, preferably 1.5-3.0, and the weight ratio of the Cu to the microemulsion loaded Ni is 0.1-1.0, preferably 0.3-0.7, and the weight ratio of the Pd to the microemulsion loaded Ni is 0.03-0.04%, preferably 0.032-0.035%, based on the mass of the catalyst as 100%; wherein the microemulsion-supported Ni, Cu and Pd are mainly distributed in macropores of 300-640 nm of the carrier.
2. The carbon dioxide cut front-end deethanization front-end hydrogenation catalyst according to claim 1, characterized in that the microemulsion supported Pd content is 1/250-1/400, preferably 1/300-1/350 of the microemulsion supported Ni + Cu content.
3. The carbon dioxide fraction front-end deethanization front-end hydrogenation catalyst according to claim 1, characterized in that during the preparation of the catalyst, supersaturated impregnation is adopted for both solution-method Pd loading and solution-method Ni loading.
4. The carbon dioxide cut front-end deethanization front-end hydrogenation catalyst according to claim 1, characterized in that the microemulsion mode loading process comprises: dissolving precursor salt in water, adding oil phase, surfactant and cosurfactant, and stirring to form microemulsion, wherein the oil phase is alkane or cycloalkane, the surfactant is ionic surfactant and/or nonionic surfactant, and the cosurfactant is organic alcohol.
5. The carbon dioxide fraction front-end deethanization front-end hydrogenation catalyst according to claim 4, characterized in that in the microemulsion loading process, the oil phase is C6-C8 saturated alkane or cycloalkane, preferably cyclohexane, n-hexane; the surfactant is an ionic surfactant and/or a nonionic surfactant, preferably the nonionic surfactant, and more preferably polyethylene glycol octyl phenyl ether or cetyl trimethyl ammonium bromide; the cosurfactant is C4-C6 alcohol, preferably n-butanol and/or n-pentanol.
6. The hydrogenation catalyst before deethanization before carbon dioxide fraction as set forth in claim 4, wherein in the microemulsion, the weight ratio of the water phase to the oil phase is 4.0-5.0, the weight ratio of the surfactant to the oil phase is 0.10-0.40, and the weight ratio of the surfactant to the co-surfactant is 1-1.2.
7. The carbon dioxide fraction front-end deethanization front-end hydrogenation catalyst according to claim 1, characterized in that the step of loading Pd on microemulsion is after the step of loading Ni and Cu on microemulsion during the preparation process of the catalyst.
8. The carbon dioxide fraction front-end deethanization front-end hydrogenation catalyst according to claim 1, characterized in that the solution-method loading of Pd is not limited in sequence with the Ni/Cu microemulsion loading during the preparation process of the catalyst.
9. The carbon dioxide fraction front-end deethanization front-end hydrogenation catalyst according to claim 1, characterized in that the step of solution-method Ni loading is after the step of solution-method Pd loading in the preparation process of the catalyst.
10. The carbon dioxide cut front-end deethanization front-hydrogenation catalyst of claim 1, characterized in that the support is alumina or primarily alumina; carrier Al2O3The crystal form is a mixed crystal form of theta and alpha; the mass fraction of alumina in the carrier is more than 80 percent.
11. The carbon dioxide cut front deethanization front hydrogenation catalyst according to claim 1, characterized in that the catalyst comprises the following steps in the preparation process:
(1) dissolving precursor salts of Ni and Cu in water, adding an oil phase, a surfactant and a cosurfactant, fully stirring to form a microemulsion, controlling the particle size of the microemulsion to be larger than 72nm and smaller than 640nm, adding a carrier into the prepared microemulsion, soaking for 0.5-4 hours, filtering out residual liquid, drying for 1-6 hours at the temperature of 60-120 ℃, and roasting for 2-8 hours at the temperature of 300-600 ℃ to obtain a semi-finished catalyst A;
(2) dissolving a precursor salt of Pd in water, adjusting the pH value to 1.5-2.5, adding the semi-finished catalyst A into a Pd salt solution, soaking and adsorbing for 0.5-4 h, drying at 100-120 ℃ for 1-4 h, and roasting at 400-550 ℃ for 2-6 h to obtain a semi-finished catalyst B;
(3) carrying out Ni loading on a small part of Ni by a solution method by a saturated dipping method, namely, preparing a Ni salt solution which is 80-110% of the saturated water absorption of a carrier, adjusting the pH value to be 1-5, and roasting a semi-finished product catalyst B at 500-550 ℃ for 4-6 hours after Ni loading on the semi-finished product catalyst B to obtain a semi-finished product catalyst C;
(4) dissolving Pd precursor salt in water, adding an oil phase, a surfactant and a cosurfactant, fully stirring to form a microemulsion, controlling the particle size of the microemulsion to be larger than 72nm and smaller than 640nm, adding a semi-finished catalyst C into the prepared microemulsion, soaking for 0.5-4 hours, filtering out residual liquid, drying for 1-6 hours at the temperature of 60-120 ℃, and roasting for 2-8 hours at the temperature of 300-600 ℃ to obtain the required catalyst.
12. The carbon dioxide cut front deethanization front hydrogenation catalyst according to claim 1, characterized in that before the hydrogenation reaction, reduction is performed at 150-200 ℃.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10309463A (en) * | 1997-05-13 | 1998-11-24 | Showa Denko Kk | Catalyst for hydrogenation reaction |
| DE102009018109A1 (en) * | 2009-04-20 | 2010-11-18 | Süd-Chemie AG | Preparation of a supported silver (Ag)/palladium (Pd) catalyst, useful for hydrogenation of acetylenic hydrocarbons (acetylene or propylene), comprises providing a Ag/Pd mixed oxide, and applying the mixed oxide on a catalyst support |
| CN104096573A (en) * | 2013-04-03 | 2014-10-15 | 中国石油天然气股份有限公司 | Preparation method of high-coking resistance selective-hydrogenation catalyst |
| CN104098425A (en) * | 2013-04-03 | 2014-10-15 | 中国石油天然气股份有限公司 | C2 fraction selective hydrogenation method |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10309463A (en) * | 1997-05-13 | 1998-11-24 | Showa Denko Kk | Catalyst for hydrogenation reaction |
| DE102009018109A1 (en) * | 2009-04-20 | 2010-11-18 | Süd-Chemie AG | Preparation of a supported silver (Ag)/palladium (Pd) catalyst, useful for hydrogenation of acetylenic hydrocarbons (acetylene or propylene), comprises providing a Ag/Pd mixed oxide, and applying the mixed oxide on a catalyst support |
| CN104096573A (en) * | 2013-04-03 | 2014-10-15 | 中国石油天然气股份有限公司 | Preparation method of high-coking resistance selective-hydrogenation catalyst |
| CN104098425A (en) * | 2013-04-03 | 2014-10-15 | 中国石油天然气股份有限公司 | C2 fraction selective hydrogenation method |
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