The effect of the thermal pretreatment on the performance of ZnO/Cr 2 O 3 catalysts applied in high-temperature methanol synthesis

Cr2 O3 Promoted In2 O3 Catalysts for CO2 Hydrogenation to Methanol

Cr2 O3 was applied to study the modification of In2 O3 based catalysts for CO2 hydrogenation to methanol reaction. Combined with X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), etc., the structure of the catalysts was characterized. The reaction performances for CO2 hydrogenation to methanol were evaluated on a stainless-steel fix-bed reactor. The results showed that solid solutions were formed for the Cr2 O3 promoted In2 O3 catalysts. The important role of electronic interaction between Cr2 O3 and In2 O3 was revealed in the hydrogenation reaction. In1.25 Cr0.75 O3 sample exhibited the highest methanol yield, which was 2.8 times higher than that of pure In2 O3 . No deactivation was observed for In1.25 Cr0.75 O3 sample during the 50 hours of reaction. The improved catalytic performance may be due to the formation of the solid solutions and the highest amount of oxygen vacancies.

The influence of temperature on the physicochemical properties of products of pyrolysis of leather-tannery waste

The present paper examines the pyrolysis of waste from leather tanneries at 300-500 °C. These studies are important because of difficulties in the utilisation of this type of waste as well as its energy potential as fuel. The pyrolysis of tannery waste and data from the relevant literature showed that thermal degradation can be explained using tanned collagen as a reference. Moreover, the experimental results indicated that this process is highly non-linear, due to various mechanisms of heat transport which cause temperature differences in a laboratory pyrolysis reactor. Thermogravimetric analysis has shown that the greater part of mass loss is observed between 80 and 500 °C and that the most significant mass release occurs at 325 °C. Moreover, the proportions of CO₂ and CO decrease along with increasing temperatures. The paper presents characteristics of the composition of solid, liquid, and gaseous products of leather-waste pyrolysis at various temperatures. The maximum heating value of gaseous products at 500 °C was 9.54 MJ/Nm³. An increase from 300 to 500 °C results in the dominant position of condensation polymerisation; the maximum value of the liquid phase yield is reached at 400 °C (42%). HHV analysis of the resulting char showed a maximum value of 21.18 MJ/kg at 450 °C. The results of oxidised component analysis showed that the major oxidised component of char was chromium oxide (Cr₂O₃), with a content of approximately 8.5% at all pyrolysis temperatures.