Preparation,Characterization Of Supported Ni₂P Catalysts And Their Catalytic Study On Hydrodesulfurization And Hydrodenitrogenation

In the petrochemical process,the existence of sulfur and nitrogen can corrode its equipment,cause catalyst poisoning and result in generating colloid and precipitation at the process of oil storage,which influence the quality and storage stability of product.In addition,during combustion process of sulfur and nitrogen in the oil,they produces sulfur oxides and nitrogen oxides which cause environmental pollution and threate human health.Therefore,study on desulfurization and denitrification research receives increasing interest.Phosphide catalyst is considered as a new generation of hydrogenation catalyst,following the traditional bimetallic catalyst,sulfide,nitride and carbide catalyst,phosphorus compounds catalyst.What's more,Ni2P catalyst,not only has a higher activity of hydrodesulfurization and hydrodenitrogenation,but also has better resistance to carbon deposition and anti-poisoning ability.not only has high activity and good stability.At present,the carriers of Ni2P catalyst have Al2O3,ZrO2,TiO2,SiO2 and other single oxides.However,because there are many problems,such as low activity,small specific surface area,bad thermal stability,poor mechanical strength which makes Ni2P catalyst difficult to meet the requirements of deep desulfurization.Compared to single oxides,composite oxide carriers of TiO2-Al2O3 and ZrO2-Al2O3 have a unique physical and chemical nature,which is a new generation of hydrotreating catalysts.In recent years,they show that special features in many fields and also receive on extensive attention on their preparation methods and nature.In this thesis,the catalytic behaviors of thiophene hydodesulfurization and pyridine hydrogeitrification over the supported Ni2P catalysts were systematically studied.A series of supported Ni2P catalysts on TiO2-Al2O3 and ZrO2-Al2O3 were firstly prepared via temperature-programmed reduction(H2-TPR).The structure characteristics of samples have been characterized by means of X-ray powder(XRD)etal.Thiophene hydodesulfurization and pyridine hydrogeitrification were chosen as a model reaction to investigate the influences of preparation conditions of carriers,conditions of catalysts and readuction on catalytic activity.Results showed that Ni2P is the main phase on the TiO2-Al2O3 supported catalysts,thiophene hydodesulfurization and pyridine hydrogeitrification conversion reache a maximum with TiO2 content of 80wt%,carrier calcination temperature of 550?,catalyst calcination temperature of 500?,Ni2P loading of 30wt%.Ni2P is also the main phase on the ZrO2-Al2O3 supported catalysts.Thiophene hydodesulfurization and pyridine hydrogeitrification conversion reach a maximum with ZrO2 content of 20wt%,carrier calcination temperature of 500-550?,catalyst calcination temperature of 500?.