Co-precipitated Cu/ZnO/Al2O3 sorbent for removal of odorants t-butylmercaptan (TBM) and tetrahydrothiophene (THT) from natural gas

The removal of sulfur-containing odorants from natural gas has been investigated by using sorption. The CuO/ZnO/Al2O3 sorbents were prepared by a coprecipitation/aging method. A reduced sorbent, namely, Cu/ZnO/Al2O3, has a sorption capacity of 0.5 mmol/g at 250 degrees C 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/Al2O3) 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.