EXPERIMENTAL STUDY ON THE SEPARATION OF CATALYTIC PYROLYSIS DRY GAS VIA HYDRATE FORMATION IN TBAB SOLUTION

摘要

In order to purify the ethylene in catalytic pyrolysis dry gas, the separation of catalytic pyrolysis dry gas (CH4+C2H4+C2H6+CO2+H2) via hydrate formation in tetra-n-butyl ammonium bromide (TBAB, 0.617mol%) solution was studied. After the determination of catalytic pyrolysis dry gas hydrate formation conditions in TBAB solution, the separation experiments were carried out in (catalytic pyrolysis dry gas+TBAB+H2O) system. The experimental results show that catalytic pyrolysis dry gas will form hydrate much more easily after adding TBAB in water under a certain temperature range. On this basis, in TBAB solution (0.617mol%), the vapor-to-water ratio of 100:1 and the reaction pressure of 3.0 MPa was selected; the separation experiments were conducted orderly at 278.15~280.15 K, and the C2H4 in catalytic pyrolysis dry gas was meant to be condensed in hydrate phase. The results show that, at 279.15 K, through one equilibrium separation the concentration of C2H4 can increase from 53.13 mol% to 73.56 mol% and the recovery ratio of C2H4 is 62.07%, which reflects a satisfactory separation effect. Since the hydrate separation technology can substantially simplify the separation process of catalytic pyrolysis dry gas, and the hydrates are not easy to agglomerate in TBAB solution, it is quite suitable for the separation of catalytic pyrolysis dry gas and has a broad prospect in actual industrial application.