Catalyst Study For Methane Assisted Hydrogenation And Reforming Of Heavy Oil

As the world’s crude oil resources are decreasing,the trend of heavy crude oil is becoming more and more obvious,and the environmental regulations are getting stricter and stricter under the background of"carbon peaking and carbon neutral",it is imperative to upgrade the traditional heavy oil processing technology.The current means of lightening heavy oil relies on hydrogenation technology,a process that uses a bifunctional catalyst with a hydrogenation center and a cracking center and requires a large amount of hydrogen to participate in the reaction.Most of the industrial hydrogen is converted from coal and natural gas,the process is complicated and the cost is high,therefore,it is crucial to reduce the hydrogen consumption and improve the selectivity of the added value products to improve the economic efficiency.It is found that methane can activate and participate in the heavy oil reforming reaction at 400-600°C,which can supply hydrogen,increase carbon and optimize product distribution,and can significantly reduce the production cost of hydro reforming in heavy oil lightening process.In this paper,the reaction process of thick-ring aromatic hydro reforming under methane-containing atmosphere was studied,and the catalytic reaction performance of thick-ring aromatic hydrocracking with carbonized Ni-Mo/Hβin methane-containing atmosphere and the effect of hydrothermal treatment of Hβmolecular sieve on the catalyst activity and stability were discussed,based on which the hydro reforming performance of FCC slurry under the action of carbonized Ni-Mo/Hβand methane-containing atmosphere was investigated.Firstly,this paper investigates the performance of the carbocation state catalysts involved in the hydrogenation of thick cyclic aromatic hydrocarbons under methane-containing atmosphere,and investigates the naphthalene hydrogenation reaction under different carbocation temperatures and different gas atmospheres,showing that Ni-Mo-C/Hβcatalysts with different carbocation temperatures can participate in the reaction and activate methane,and characterize the catalysts by using XRD,BET,NH₃-TPD,H₂-TPR,XPS and other technical means.The results showed that the conversion of naphthalene was 99.97%and the selectivity of benzene,toluene,and xylene was 17.76%,25.17%,and 20.47%for the methane-containing atmosphere at the carbonization temperature of 700°C and the loadings of Ni O and Mo O₃ were3.5 wt%and 10 wt%,respectively.Compared with the hydrogen atmosphere,the selectivity of benzene was significantly lower,while that of toluene and xylene was increased.Ni and Mo carbides are active sites for activation of CH₄ and H₂,and the activated methane can participate in the hydrocracking process of naphthalene,providing methyl groups thereby improving the selectivity of the methyl-containing side chain products in the liquid state.Secondly,the hydrothermal treatment was used to modify the pore structure of catalyst Hβand to determine the optimal hydrothermal treatment temperature and time to modify the catalytic performance of hydrogenation under methane-containing atmosphere.The characterization by XRD,BET,Py-IR,and NH₃-TPD revealed that the hydrothermal treatment conditions can dealuminate the carrier molecular sieve skeleton and stabilize the catalyst structure;the mesopores become more numerous and the pore size increases,increasing the time for the reactants to diffuse inside the catalyst,and also avoiding the deactivation of the catalyst during the long time continuous reaction and improving the catalyst reaction performance.The results showed that the conversion of naphthalene by hydrothermal treatment at 200°C and 60min was 98.75%,and the selectivity of benzene,toluene,and xylene was 26.32%,8.61%,and2.81%,respectively.After hydrothermal treatment,the amount of carbon accumulation in the catalyst decreased significantly and the activity of the catalyst became more stable,but the toluene and xylene selection performance was significantly reduced due to large changes in product distribution caused by changes in the structure and acidity of the catalyst.Finally,the Ni-Mo-C/Hβcatalyst can effectively lighten the FCC slurry,and the hydrogenation of FCC slurry under CH₄/H₂ mixed atmosphere increases the toluene and xylene-containing methyl side chain products,part of which originates from the cracking of thick ring aromatics in heavy oil and the other part is the methane activation involved in the reaction.