Preparation And Properties Of Pt-based Sulfur-tolerant Hydrogenation Catalyst

Nowadays the air quality is getting worse and worse,which seriously affects people’s health.Excessive aromatic hydrocarbons in oil products will not only reduce the hexadecane value of diesel fuel,increase the smoke point of jet fuel,but also increase the emission of contaminated gases and particulate matter during the combustion of oil products,which will seriously affect air quality.Due to the importance of environmental protection and the restrictions on the quality standards of oil products,it is urgent to reduce the content of aromatic hydrocarbons in oil.The core of the technology is the catalyst,so the researchers are working on a new type of hydrogenation catalyst.Due to the excellent hydrogenation performance of precious metal catalysts,it is widely used in the oil refining industry.However,in the process of oil refining,precious metals are sensitive to sulfur compounds contained in crude oil and are poisoned and inactivated,thus limiting their application in the oil refining industry.Therefore,improving the sulfur resistance of the precious metal catalyst has become a research hotspot,and it is also a key issue that this topic wants to solve.A series of load-type catalysts with different precursor,different carrier,different roasting and different load were prepared in this paper.In the hydrothermal synthesis,the metal precursor Pt（NH₃）₄Cl₂ was introduced into the aluminosilicate gel to synthesize the mesoporous natriuretic stone that encapsulates Pt.The effects of different crystallization temperature,different crystallization time,different adding amount of molds on Pt@mesoporous SOD hydrogenation and sulfur resistance were studied,and compared with the performance of load type catalysthydrogenationandsulfurresistance.Thesynthetic Pt@mesoporous SOD was subjected to ion exchange experiments with alkali metals and alkaline earth metal ions to prepare different monovalent and divalent cationic Pt@mesoporous SOD to study the hydrogenation and sulfur resistance of different ion radii and different valence States.The experiment finally concluded that:（1）Through the study of the effects of different Pt precursors,different Silicon aluminum ratios,different calcination temperatures and different load quantities on the performance of the Pt type Catalyst,It was found that the benzene hydrogenation conversion rate of the H₂PtCl₆·6H₂O catalyst was higher than that of the Pt（NH₃）₄Cl₂ Catalyst,but the sulfur resistance of the H₂PtCl₆·6H₂O catalyst was not loaded.Pt（NH₃）₄Cl₂ catalyst has good sulfur resistance;For catalysts with different Silicon aluminum ratios,with the increase of Silicon aluminum ratio,the conversion rate of benzene hydrogenation appears to decrease.The effect of baking temperature on the Pt type hydrogenation catalyst was significant.With the decrease of baking temperature,the surface area of BET decreased gradually.With the decrease of roasting temperature,the conversion rate of the samples before and after poisoning also showed a decreasing trend,so as the Sulfur resistance.With the increase of the load Pt,the benzene hydrogenation conversion rate of the sample gradually increased,and the sulfur resistance of the sample gradually increased.（2）The sample poisoned by Al₂O₃ at 200℃did not have sulfur resistance.When the element analysis was performed,the S element was measured,and the Pt element content in the sample was the same as the S element content.（3）When ZSM-5 is used as the carrier,there will be bright silver-gray material during the roasting process.Combined with the Pt element content analysis,it will be known that Pt will be lost.（4）The performance of the encapsulated Pt@mesoporous natriuretic can be characterized by means of characterization tests such as XRD,N₂sorption and desorption,ICP,and benzene hydrogenation.The optimum crystallization temperature is 90℃,the optimal crystallization time is 12h,and the optimal template addition amount can be obtained.For 5ml and the best Pt addition is M（Pt）:M（Si-Al gel）（g/g）=0.03.（5）There are mixed peaks on the XRD spectrum of samples synthesized under different crystallization temperatures,different crystallization times,different modulus addition quantities,and different Pt addition conditions.The relative crystallinity of the synthetic mesoporous natriuretic stone is not high,and the BET is smaller than the surface area;The addition of inorganic salts under the conditions of optimal crystallization temperature,optimal crystallization time,optimal modulus addition,and optimal Pt addition,we can see from the characterization that adding chlorine salts can increase the relative crystallinity of the sample and BET specific surface area.There are no miscellaneous peaks on the XRD spectrum of the sample,and the addition of chlorine salt can increase the degree of crystallization of calcite.（6）In this experiment,Pt@mesoporous SOD was successfully synthesized,which provided a new idea for the preparation of hydrogenation and sulfur-resistant catalyst.（7）After Pt@MSOD is exchanged by a monovalent cation,the characteristic peak strength of the sodium stone behind H⁺exchange Na⁺is weakened,and the effect on the packaging of Pt is not significant;After Li⁺exchanges Na⁺,the characteristic peak strength of the other sodium stone is not as large as after H⁺exchange,and the characteristic peak strength of Pt is slightly enhanced,indicating that after Li⁺exchange,It may be that the Pt packed into the albite cage is exposed because of ion exchange;After K⁺swapped Na⁺,the skeleton of the albite stone was also damaged to a certain extent,and the characteristic peak strength of Pt was slightly weakened;After the K⁺ion exchange process,the Pt element analysis of the sample was performed and it was found that the loss of the Pt element of the sample was not caused by the K⁺ion exchange.（8）After Pt@MSOD is exchanged by divalent cations,the skeleton structure of the other sodium stone is destroyed to a greater extent.In particular,the characteristic diffraction peak strength of the sample Pt@MSOD-Ba is very weak,indicating that after Ba²⁺ion exchange,its skeleton structure collapsed;The characteristic peak strength of the metal center Pt is weakened,and the Ba²⁺ion exchange process will cause the loss of Pt elements.（9）Ion exchange will affect the benzene hydrogenation activity of the sample,but it will have little effect on the antitoxicity performance of the sample.