Co-Precipitated Cu/ZnO/Al_2O_3 Sorbent for Removal of Odorants t-Butylmercaptan (TBM) and Tetrahydrothiophene (THT) from Natural Gas

摘要

The removal of sulfur-containing odorants from natural gas has been investigated by using sorption. The CuO/ZnO/Al_2O_3 sorbents were prepared by a coprecipitation/aging method. A reduced sorbent, namely, Cu/ ZnO/Al_2O_3, has a sorption capacity of 0.5 mmol/g at 250℃ when the sodium content is kept below 0.027 wt %. The high sorption capacity of the sorbent is due to the better dispersion of nanocrystalline copper metal particles in a zinc oxide matrix as confirmed by X-ray diffraction analysis. The Brunauer—Emmett—Teller surface area of calcined material (Cu/ZnO/Al_2O_3) increased systematically from 18.38 to 104.26 m~2/g with the lowering of the residual "Na" concentration. The temperature-programmed reduction study revealed that high incorporation of "Na" made the reduction of the CuO phase difficult in unwashed sorbent. However, as the "Na" content is lowered below 0.027 wt %, the reduction of CuO particles occurred at much lower temperatures because of the strong interaction of nanosized CuO with ZnO particles.