Formaldehyde degradation by UV/TiO_2/O_3 process using continuous flow mode

The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g,, it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84--24 mg/m^3 by O3/TiO2flJV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m^3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/（m^3.min） and Langmuir adsorption coefficient K of 0.0268 m^3/mg were obtained.

Construction of a 3D meso-structure and analysis of mechanical properties for deposit body medium

For deposit body medium, the internal structural properties may be the controlling factors for the strength of the material and the mechanical response. Based on the results of soil-rock meso-statistics using digital imaging, a simulated annealing algorithm is adopted to expand the meso-structural features of deposit bodies in 3D. The construction of the 3D meso-structure of a deposit body is achieved, and then the particle flow analysis program PFC3 D is used to simulate the mechanical properties of the deposit body. It is shown that with a combination of the simulated annealing algorithm and the statistical feature functions, the randomness and heterogeneity of the rock distribution in the 3D inner structure of deposit body medium can be realized, and the reconstructed structural features of the deposit medium can match the features of the digital images well. The spatial utilizations and the compacting effects of the body-centered cubic, hexagonal close and face-centered packing models are high, so these structures can be applied in the simulations of the deposit structures. However, the shear features of the deposit medium vary depending on the different model constructive modes. Rocks, which are the backbone of the deposit, are the factors that determine the shear strength and deformation modulus of the deposit body. The modeling method proposed is useful for the construction of 3D meso-scope models from 2D meso-scope statistics and can be used for studying the mechanical properties of mixed media, such as deposit bodies.

Controlling the reaction network of Ni/silica derived conversion of bio-oil surrogate guaiacol

Replacing fossil carbon sources with green bio-oils is a promising route to switch to a sustainable chemical industry,although their high oxygen contents are challenging.Catalytic hydrodeoxygenation is a favored route to upgrade bio-oils to renewable fuels and basic chemicals.In this work,we investigated Ni/SiO2 catalysts with differing metal dispersity in continuous mode conversion of guaiacol with a statistical experimental design for 250℃to 400℃,2 h up to 5 h time on stream(ToS)and subsequently different residence time besides other parameters.While low temperature(250℃)promotes cyclohexanol formation from guaiacol,high temperature(400℃)inhibits hydrogenation,leading to phenol and methane.For medium temperature(340℃),the selectivity for cyclohexanone increases.Cyclohexanol and cyclohexanone(KA-oil)are the industrial basis for polyamide 6.Furthermore,we clarified the role of 2-methoxycyclohexanol(2MC)in the reaction network towards KA-oil for continuous-mode operation.Statistical analysis was used to predict and optimize product selectivity and yield,leading to the best yield of cyclohexanone/-ol at 327.5℃,low ToS,medium residence time,high particle dispersity,and medium hydrogen pressure(15 bar(g)).