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Study On The Technology Of Thermal Cracking Of Liquid Wax To α-Olefin And Oligomerization Of The α-Olefin To Poly-α-olefin

Posted on:2017-05-12Degree:MasterType:Thesis
Country:ChinaCandidate:L B ShiFull Text:PDF
GTID:2271330482998835Subject:Oil and Gas Storage and Transportation Engineering
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With the development of automobile, machinery and aviation industry and the increase of energy conservation and environmental protection, the requirement of high quality synthetic lubricant base oil is increasing rapidly. Due to domestic backward technology and the foreign advanced technology blockade of a-olefin and PAO, China need quantity import PAO from abroad every year. There is plentiful paraffin resource in China, so the process to produce PAO from thermally cracked paraffin feed is suitable. In this study, liquid wax is cracked to produce a-olefin, kinetic of liquid wax cracking is studied by means of structure oriented lumping (SOL). The pseudo slurry bed oligomerization fed by 1-decene and catalyzed by AlCl3/TiCl4 is studied, then selecting the suitable technology conditions to polymerize the olefin produced by liquid wax cracking in pseudo slurry bed.A new created structure vector DB and 6 structure vectors are used for building liquid wax molecular composition matrix. Then reaction rules, net and differential equations are built. Product distribution is got by solving the differential equations. The reaction rate constants are calculated by Materials Studio software. In the end, the SOL model can accurately calculate product distribution in different condition. Analyzing the result calculated by the SOL model, reaction temperature 660℃, residence time 3.5s steam liquid wax ratio 0.1 are determined the optimum reaction condition. The calculated result of per-pass conversion, a-olefin yield and a-olefin selectivity are 31.21%,17.23%, and 12.01%. After experiment test, the relative error of conversion, a-olefin yield and a-olefin selectivity are 2.36% 1.29% and 6.47%. Compared with 54# semi-refined paraffin wax, C8-C12 a-olefin yield of liquid wax cracking is higher to 13.4%. The distribution of carbon number is narrow.The a-olefin produced by liquid wax cracking is polymerized in pseudo slurry bed at optimum reaction condition. The results are 90.5% of yield,101.32 mm2/s of kinematic viscosity in 40℃,14.43mm2/s of kinematic viscosity in 100℃,147 of viscosity and -49℃ of solidify point. The main properties of synthesized product meet the requirements of commercial PAO-15 lubricant base oil. The results of immobilizing TiCl4 on supporters which are y-A12O3, silica gel, HZSM-5 (Si/Al=50), HZSM-5 (Si/Al=360) show that y-A12O3 is the optimum supporter and Ti element content reach 25.75(wt)%. IR, GPC and’H NMR analyses show that PAO synthesized by the olefin produced by liquid wax cracking contain mainly saturated hydrocarbon and trace of isomerised olefins, and the dispersion index and branched degree of the PAO are 1.486 and 0.215. Compared with it branched degree of the PAO synthesized by 1-decene is lower.
Keywords/Search Tags:liquid wax, α-olefin, structure oriented lumping, lubricant base oil
PDF Full Text Request
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