Study On C4Butene Adsorption Performance Of The Prepared Adsorbents

n-Butene is an important chemical raw material, which can be used to produce methylethyl ketone through the direct hydration and can also be used as comonomers for linearlow-density polyethylene. n-Butene is obtained from mixed C4by distillation or extraction,which remain to be energy-intensive process because of the close relative volatilities of C4olefin/alkanes. In order to save energy, improve efficiency and meet increasingly stringentenvironmental requirements, π complexation adsorption separation technology become animportant research direction, which exploit the fact that olefins and transition metal ions canform a reversible pi-complex bond. In this paper, the C4olefin/paraffin separationperformance of adsorbents prepared at different conditions was studied through fixed bedadsorption experiment. For ion exchange adsorbent, the effects of metal ions, carriers, ionexchange temperature, ion exchange times, roasting temperature on the separation of C4olefin/paraffin had been investigated. For monolayer dispersion adsorbent, the effects ofimpregnation method, carrier, load on the separation of C4olefin/paraffin had beenresearched. At the same time, the desorption performance of adsorbents was also bediscussed.Transition metal ions can and complex with adsorbate. Experiments proved the Cu2+cannot be formed pi-complex bond with butane. Ag+modified adsorbent is significantly betterthan the Zn2+modified adsorbent with the configuration of (n-1)d10ns0for the separation ofC4olefin/alkanes. NaY,13X are more suitable for adsorbent carrier between compared withZSM-5and732styrene cation exchange resin. The acidic sites of γ-Al2O3does not improvethe pi-complexation. The amount of butene complexed with Ag+of γ-Al2O3and SiO2were0.53C4H8/Ag+and0.76C4H8/Ag+, respectively. Due to the large specific surface area of SiO2,SiO2is suitable for the adsorbent carrier than γ-Al2O3. The preparation conditions of ion exchanged zeolites was studied. It’s showed that forNa13X zeolite, the ion exchange temperature of60℃, four exchanging times, roastingtemperature of600℃are the best condition. For NaY zeolite, adsorption effect was the bestin condition that the ion exchange temperature was30℃with one exchanging times, andadsorbents were roasted at500℃. By researching the amount of AgNO3loaded on SiO2andSBA-15, it was found that a monoplayer dispersion on SiO2and SBA-15is0.29g/g and0.45g/g, respectively.In addition, through the study of the conditions on the adsorption and desorptionconditions, for this experimental device, adsorption temperature of39℃and feed gas flow of40mL/min, good adsorption capacity and selectivity for butene were achieved. Experimentalresults of adsorbent regeneration showed that the adsorbent could be completely regeneratedafter being purged4hours by N2in constant temperature of200℃.