No abstract

The K/Cu-Zn catalyst has been synthesized by the co-precipitation method coupling with impregnation method and the catalytic performances for the reverse water gas shift (RWGS) reaction and mixed alcohols synthesis from CO2 hydrogenation have been investigated. The catalytic activity and product distribution depend strongly on reaction temperature, pressure, space velocity and the molar ratio of H2/CO2. These results indicated that the optimal conditions for CO2 hydrogenation over K/Cu-Zn catalyst were as follows: 350 K, 6.0 MPa, 5000 h-1 and H2/CO2 = 3.0, under which the selectivity of CO and mixed alcohols reach 84.27 wt% and 7.56 wt%, respectively. The outstanding performances for RWGS reaction and mixed alcohols synthesis of K/Cu-Zn catalyst can be due to the well dispersion of Cu active component.

Pyrolysis of high density polyethylene (HDPE) to polyethylene wax (PEW) in a 1 L continues stirred-tank reactor (CSTR) was studied at 360-420 °C with 5-240 min, yield of PEW was discussed and the properties such as the drop melting point and average molecular weight of wax were determined. The PEW had a melting point of 104-120 °C, and an average molecular weight of around 3000 with a good dispersity at 673 K. Moreover, the composition of wax determined by fourier transform infrared spectroscopy (FT-IR) indicated that it was less branched than commercial waxes.

Bifunctional Pt/HZSM-5, Pt/HBeta, Pt/HMCM-41 and Pt/HSAPO-11 catalysts were prepared using pseudoboehmite as a binder. The H2-TPR profiles, scanning electron microscope (SEM) and brunauer-emmett-teller (BET) pointed out that reducibility of catalysts and textural properties. These bifunctional catalysts have been tested in long-chain olefins hydroisomerization. The experiments were carried out at 320oC under 2.0 MPa of hydrogen and at 3.0 h-1WHSV. Complete hydrogenation of long-chain olefins was observed over Pt/HMCM-41 and Pt/HSAPO-11. Hydroisomerization reactions also occured in the case of Pt supported strong acidic molecular sieves (HZSM-5 and HBeta). The result suggests product distribution of long-chain olefins hydroisomerization is dependent on the balance between the acid and metallic functions in catalysts.

Waste plastics can be converted to diesel oil and lube base oil by thermal pyrolysis and dewaxing. ZEM-5, H-ZEM-5, Fe/H-ZEM-5 and Co/H-ZEM-5 catalyst were prepared. The influences of additive metals and type of molecular sieves on catalyst were discussed. The results showed that the additon of metallic components enhances the activity of catalyst, produces the low pour point diesel oil, and greatly reduces the pour point of lube base oil. The catalyst impregnated with Fe was more effective than one impregnated with Co. The qualities of oil production were also improved more with H-ZEM-5 than ZEM-5.