Research And Development On Presulfurizing Agent For Catalytic Hydrogenation

This presulfurizing agent was synthesized using halogenated alkanes, sodium sulfide and elemental sulfur as raw materials under phase transfer catalyst, the whole synthesis process includes two steps. The effects of reaction temperature, reaction time, the amount of catalyst and the amount of elemental sulfur on the sulfur content(quality Score)of the product were investigated, and the best synthesis conditions were determined by orthogonal experiment The properties such as the decomposition temperature, viscosity sulfur content of the synthesized prevu丨canizing agent were analyzed; And gas chromatography- mass spectrometry was used for the analysis of the possible reaction mechanism; A 30 m L fixed bed high-pressure hydrogenation miniature continuous experimental apparatus was used to investigate the presulfurization effects of hydrogenation catalyst through the wet prevulcanized methods, and the effects of the amount of curing agent, the curing heating-up process and hydrogen to oil ratio on the activity of the presulfided catalyst were investigated, and the best prevulcanization process conditions was determine; Compared the application of the presulfurizing agent and conventional sulfurizing agent, while the sulfided hydrogenation catalysts were characterized by XRD, SEM, BET and so on.The results show: the presulfurizing agent synthesized above has high flash point, high sulfur content and wide range of decomposition temperature, and as compared with conventional synthetic methods, this method has milder synthesis conditions and higher reaction conversion rate. The optimum synthesis process were: the molar ratio of sodium sulfide and sulfur is 4.5: 1,the first step reaction temperature is 50 °C, the first step reaction time is 30 min, the second step reaction time is 1.25 h, the second step reaction temperature is room temperature, the amount of phase transfer catalyst is 0.03 times of sodium sulfide(molar ratio), the amount of bromoethane is 2 times of sodium sul Fide(molar ratio), the composition and the content of each component of the sulfurizing synthesized above were analyzed by GC-MS, and a possible reaction mechanism is inferred. The presulfurizing agent was used for sulfurizing a hydrogenation, and the optimum activating conditions were: the reaction pressure is 2.0 MPa, the LHSV(liquid hourly space velocity) is 1.0 h"1, the V(H2)/V(oil) is about 100,the sulfur content of sulfurized oil is 2.0%(Quality Score), the heating-up prosess, first, heating though room temperature to 200 ℃, and keep for 4 h, then heating the temperature from 200 ℃to 290 ℃ at a rate of 15 ℃·h-1, then keep for 6 h, and then heating to 340 ℃ at the same rate, then keep the temperature for 2 h. The whole presulfurization prosess needs about 21.3 h, and the surfurized hydrogenation catalyst has high sulfidity and activity.