阅读说明：本技术 一种高分散钯-掺硫活性炭催化剂及其制备与应用 (High-dispersion palladium-sulfur-doped active carbon catalyst and preparation and application thereof ) 是由 张群峰 周媛 张超杰 马磊 卢春山 丰枫 吕井辉 李小年 于 2019-08-30 设计创作，主要内容包括：本发明提供了一种高分散钯-掺硫活性炭催化剂及其制备方法与应用,本发明制备方法采用先水热后焙烧的方法进行硫的掺杂,该方法可使得掺杂的硫更稳定地存在于碳材料的表面；浸渍法负载贵金属的方法简便,成本低；所述高分散钯-掺硫活性炭催化剂中,载体表面的掺入的硫起到了锚定作用,可以实现钯纳米颗粒的高度分散和尺寸调控,有效提升了贵金属的原子利用率；硫与金属之间的强烈的相互作用保证了催化剂的高度稳定性,使得金属纳米颗粒在乙炔加氢反应过程中不易团聚和流失,有利于延长催化剂寿命；本发明所述催化剂在乙炔加氢反应中对乙烯的选择性高,乙炔可达到完全转化,并且使用条件温和、稳定性好,催化剂用量少,催化剂使用寿命长。(The invention provides a high-dispersion palladium-sulfur-doped activated carbon catalyst, a preparation method and application thereof, the preparation method adopts a method of firstly carrying out hydrothermal and then roasting to carry out sulfur doping, and the method can ensure that the doped sulfur exists on the surface of a carbon material more stably; the method for loading noble metal by the dipping method is simple and convenient and has low cost; in the high-dispersion palladium-sulfur-doped activated carbon catalyst, the doped sulfur on the surface of the carrier plays a role in anchoring, so that the high dispersion and size regulation of palladium nanoparticles can be realized, and the atom utilization rate of noble metal is effectively improved; the strong interaction between sulfur and metal ensures the high stability of the catalyst, so that the metal nano particles are not easy to agglomerate and run off in the acetylene hydrogenation reaction process, and the service life of the catalyst is prolonged; the catalyst has high selectivity to ethylene in the acetylene hydrogenation reaction, can completely convert acetylene, and has the advantages of mild use condition, good stability, small catalyst consumption and long service life.)

1. A high-dispersion palladium-sulfur-doped active carbon catalyst is characterized by being prepared by the following method:

(1) Preparing sulfur-doped activated carbon: dissolving a sulfur-containing precursor in deionized water, adding activated carbon, stirring and mixing uniformly at 40-80 ℃ at the speed of 300-1000 r/min, heating to 180-300 ℃ for hydrothermal for 10-40 h, cooling to room temperature, filtering, drying a filter cake at 40-80 ℃ for 8-15 h in vacuum, heating the dried solid to 400-800 ℃ in an inert gas atmosphere, and roasting for 2-8 h to obtain sulfur-doped activated carbon;

The mass ratio of the sulfur-containing precursor to the activated carbon in terms of sulfur element is 0.01-0.1: 1;

The sulfur-containing precursor is Na₂S、K₂One or a mixture of more than two of S, NaHS and KHS in any proportion;

(2) Loading of noble metal: uniformly mixing the obtained sulfur-doped active carbon and a noble metal compound solution by adopting an isometric impregnation method, standing for 6-12H, drying in vacuum at 40-80 ℃ for 12-20H, and then carrying out H₂Reducing for 1-3 h at 50-200 ℃ in the atmosphere to obtain the high-dispersion palladium-sulfur-doped active carbon catalyst;

The noble metal compound solution is prepared by dissolving a noble metal compound in a solvent; the noble metal compound is chloropalladate, sodium chloropalladate or palladium acetate.

2. The highly dispersed palladium-sulfur-doped activated carbon catalyst according to claim 1, wherein in the step (1), the mass ratio of the sulfur-containing precursor to the activated carbon is 0.03-0.08 in terms of elemental sulfur: 1.

3. The highly dispersed palladium-sulfur doped activated carbon catalyst of claim 1 wherein the resulting catalyst has a noble metal Pd loading of 0.01 to 0.15 wt% based on the mass of the support.

4. Use of the highly dispersed palladium-sulfur-doped activated carbon catalyst of claim 1 in the selective hydrogenation of acetylene.

5. The application of claim 4, wherein the method of applying is:

before reaction, the catalyst is firstly added in H₂Reducing for 1-4 h at 50-200 ℃ in the atmosphere; the reaction conditions are as follows: the temperature is 60-180 ℃, the pressure is 0.1-1 MPa, and the airspeed is 1000-15000 h^-1the initial gas composition of the reaction is (volume fraction): 0.33% C₂H₂、0.66％H₂、33.3％C₂H₄The balance N₂。

(I) technical field

The invention relates to a high-dispersion palladium-sulfur-doped active carbon catalyst, a preparation method thereof and application thereof in reaction for preparing ethylene by selective hydrogenation of acetylene.

(II) background of the invention

Ethylene is an important industrial organic synthetic raw material, and is mainly used for producing polyethylene, polyvinyl chloride, ethylene oxide, ethanol, acetaldehyde and the like on a large scale. Because of its wide use, ethylene has a great production demand in industry. Ethylene is mainly derived from the cracking of naphtha, and a byproduct acetylene is inevitably generated in the process, and low polymers formed by the polymerization of the acetylene have serious poisoning effect on a downstream ethylene polymerization catalyst. Commercial ethylene feed gas often contains 1% acetylene. Thus, the selective removal of small amounts of residual acetylene from ethylene streams is one of the important processes in the chemical industry, which requires that the feed gas be removed to below 5 ppm. Pd is widely applied to acetylene hydrogenation selective hydrogenation reaction as a high-activity noble metal, but has the problems of low ethylene selectivity, easy excessive hydrogenation and the like. Therefore, finding an effective means for modifying the Pd catalyst and improving the selectivity of ethylene has great significance for industrial production.

disclosure of the invention

The invention relates to a high-dispersion palladium-sulfur-doped active carbon catalyst, a preparation method thereof and application thereof in reaction for preparing ethylene by selective hydrogenation of acetylene. The method disclosed by the invention is simple to operate, generates less pollution, effectively enables the Pd metal to be highly dispersed on the surface of the carrier, improves the atom utilization rate of the noble metal, and is beneficial to industrial application.

The catalyst prepared by the invention can efficiently selectively convert a small amount of acetylene in ethylene airflow into ethylene, and has the advantages of high catalyst activity, good selectivity and stability, repeated recycling and the like.

The technical scheme of the invention is as follows:

a high-dispersion palladium-sulfur-doped active carbon catalyst is prepared by the following method:

(1) Preparing sulfur-doped activated carbon: dissolving a sulfur-containing precursor in deionized water, adding activated carbon, stirring and mixing uniformly at 40-80 ℃ at the speed of 300-1000 r/min, heating to 180-300 ℃ for hydrothermal for 10-40 h, cooling to room temperature (20-30 ℃), filtering, vacuum drying a filter cake at 40-80 ℃ for 8-15 h, heating the dried solid to 400-800 ℃ in an inert gas atmosphere, and roasting for 2-8 h to obtain sulfur-doped activated carbon;

The mass ratio of the sulfur-containing precursor to the activated carbon in terms of sulfur element is 0.01-0.1: 1, preferably 0.03 to 0.08: 1;

the sulfur-containing precursor is Na₂S、K₂one or a mixture of more than two of S, NaHS and KHS in any proportion;

the particle size of the activated carbon is 100-1000 meshes, preferably 200-800 meshes, and the specific surface area is 600-2000 m²A concentration of 1000 to 1800m is preferred²The pore volume is 0.3-0.8 mL/g, preferably 0.4-0.7 mL/g;

The inert gas is N₂he or Ar;

(2) Loading of noble metal: uniformly mixing the obtained sulfur-doped active carbon and a noble metal compound solution by adopting an isometric impregnation method, standing for 6-12H, drying in vacuum at 40-80 ℃ for 12-20H, and then carrying out H₂Reducing for 1-3 h at 50-200 ℃ in the atmosphere to obtain the high-dispersion palladium-sulfur-doped active carbon catalyst;

The noble metal compound solution is prepared by dissolving a noble metal compound in a solvent; the invention has no special requirements on the concentration of the noble metal compound solution, and the technical personnel in the field can carry out conventional preparation according to the actual needs; the noble metal compound is chloropalladic acid, sodium chloropalladate or palladium acetate, preferably chloropalladic acid; the solvent can be deionized water, ethanol, 10-36 wt% HCl aqueous solution and the like, and the invention has no special requirement on the solvent; meanwhile, by adopting an isometric impregnation method, the noble metal can be considered to be fully loaded;

In the obtained catalyst, the noble metal (Pd) is supported in an amount of 0.01 to 0.15 wt%, preferably 0.05 to 0.1 wt%, based on the mass of the carrier.

The high-dispersion palladium-sulfur-doped active carbon catalyst prepared by the invention can be applied to the selective hydrogenation reaction of a small amount of acetylene in ethylene.

Before reaction evaluation, the catalyst is firstly put in H₂reducing for 1-4 h at 50-200 ℃ in the atmosphere; the reaction conditions are as follows: the temperature is 60-180 ℃ (preferably 80-120 ℃), the pressure is 0.1-1 MPa, and the airspeed is 1000-15000 h^-1(preferably 4000 to 8000 h)^-1) The initial gas composition of the reaction is (volume fraction): 0.33% C₂H₂、0.66％H₂、33.3％C₂H₄The balance N₂。

Compared with the prior art, the invention has the following advantages:

(1) According to the preparation method of the high-dispersion palladium-sulfur-doped active carbon catalyst, sulfur is doped by a method of firstly carrying out hydrothermal treatment and then carrying out roasting, and the method can enable the doped sulfur to exist on the surface of a carbon material more stably; the method for loading noble metal by the dipping method is simple and convenient and has low cost;

(2) In the high-dispersion palladium-sulfur-doped activated carbon catalyst, the doped sulfur on the surface of the carrier plays a role in anchoring, so that the high dispersion and size regulation of palladium nanoparticles can be realized, and the atom utilization rate of noble metal is effectively improved; the strong interaction between sulfur and metal ensures the high stability of the catalyst, so that the metal nano particles are not easy to agglomerate and run off in the acetylene hydrogenation reaction process, and the service life of the catalyst is prolonged;

(3) The catalyst has high selectivity to ethylene in the acetylene hydrogenation reaction, and the acetylene can be completely converted;

(4) The catalyst of the invention has mild use condition, good stability, less catalyst consumption and long service life.

(IV) detailed description of the preferred embodiments

The present invention is further illustrated by the following specific examples, but the scope of the invention is not limited thereto.