Band 17, Heft 12 -

Tri- reforming is the main key for thermal intensification of hydrogen production based process. The arrangement of dry reforming, endothermic steam reforming, and exothermic partial oxidation make up a tri-reforming procedure. The benefit of the tri-reforming procedure is that it can be practical for energy supply for the dry and steam reforming reactions from the production of heat from the exothermic oxidation reaction. Some scientists have reviewed its usage with biogas feedstock to generate synthesis gas because the tri-reforming procedure employs CO 2 . Furthermore, the tri-reforming procedure is a technique to cut CO 2 emissions in flue stack gases. In yielding synthesis gas from biological gas, two chief functioning issues give the anticipated H 2 /CO ratio that consists of the extreme conversion of methane and also prevents coke deposition. The wanted H 2 / CO ratio differs with the wanted usage for the synthesis gas. In the present paper, the published studies from 2001 until now in three classifications have been chosen for further discussion. Finally, various suggestions have been proposed to escape catalyst deactivation due to the high-temperature nature of tri-reforming as a guideline for further investigations.

The mesoporous Ni 20 /Al-KIT-6 (denoted as N 20 A x K) catalysts with different Al content (1–9 wt%) were prepared, metal Ni and KIT-6 modified by Al were used as active component and support, respectively. The physicochemical properties of the prepared N 20 A x K catalysts were characterized by H 2 -TPR, XRD, BET, TEM, and H 2 -TPD. The catalytic hydrodeoxygenation(HDO) performance of N 20 A x K catalysts was evaluated by ethyl acetate catalytic HDO. The results show that the catalytic HDO performance of the prepared N 20 A x K catalysts is related to the adsorption and activation performance for H 2 molecules, as well as the dispersion of matal Ni active components. N 20 A 5 K catalyst shows the best H 2 adsorption property and Ni dispersion. N 20 A 5 K catalyst presents superior catalytic HDO performance. At 300 °C and atmospheric pressure, the conversion of ethyl acetate and ethane selectivity of N 20 A 5 K catalyst are 99.3 % and 97.4 %, respectively. Besides, the N 20 A 5 K catalyst exhibits good stability.

The dissolution of chalcopyrite under near ambient conditions represents one of the main challenges in the copper industry. Thus, various routes have been proposed for chalcopyrite treatment, such as the use of polar organic solvents, and this has shown promising results. In this paper, we present a study of copper leaching from a chalcopyrite concentrate in aqueous acidic medium with methanol and various H 2 O 2 concentrations at 15, 30, and 40 °C. The results show that nearly complete copper extraction was attained within 5 h at 40 °C. The extraction percentages were plotted as functions of time at each temperature. The experimental data were modeled using the shrinking core model considering the cylindrical particle shape (shrinking cylinder model) within acceptable confidence levels, yielding an estimated activation energy of 24.3 kJ/mol. Furthermore, the process was dependent on the H 2 O 2 concentration, and it acts as a reagent rather than an oxidant in the leaching reaction. It was found that sulfur is the only species present in the solid phase formed during the leaching of chalcopyrite, demonstrating the co-dissolution of both copper and iron.

This paper documents CFD simulations of the gas hold-up (ɛ g ) and volumetric mass transfer coefficient (K L a) for three kinds of airlift reactors (ALRs) namely, conventional ALR, ALR with net draft tube (ALR-ndt), and packed-bed ALR with net draft tube (PBALR-ndt). The 3D two-fluid Eulerian-Eulerian model was adopted to predict the influence of superficial gas velocity on ɛ g and K L a. The simulation results were consistent with the trends described previously in the experimental work regarding ɛ g and K L a values and a good agreement was obtained (absolute error less than 20 %). Based on the simulation results, axial flow is the dominant flow in the conventional ALR while in ALR-ndt and PBALR-ndt radial flow streamlines are appeared in the reactors due to the presence of concentric net draft tube which improves their performance. The effective role of the net draft tube is proven since consequence of generation of small bubbles by passing through net draft tube is the entrainment of a larger percentage of gas bubbles from the riser into the downcomer which results in improvement of gas holdup and the K L a values. An exponential correlation is used for relating gas hold-up and mass transfer coefficient. Higher power obtained for ALR-ndt and PBALR-ndt (n ≈ 1.22) compared to ALR (n = 0.95) was indicative of high sensitivity of K L a value to gas hold-up in these reactors due to presence of the concentric net draft tube. The CFD modeling is considered to be an invaluable tool allowing us to analyze and visualize the impact of fluidic forces on hydrodynamic properties and consequently, reactor performance.

VO x /CeO 2 catalysts with various nanostructure were synthesized by the hydrothermal method and used in catalytic combustion of chlorobenzene (CB) at a low temperature. XRD, BET, TEM, Raman, XPS, and H 2 -TPR were employed to reveal that catalysts VO x on CeO 2 support had considerable activity for CB combustion. VO x /CeO 2 catalysts prepared with ammonium to adjust pH value and added P123 as a surfactant, showed the highest CB conversion ratio of 60 % at 250 °C and 100 % at 400 °C. It showed that preparation method could infect the shape evolution and surface species during the synthesis. The new phase CeVO 4 formed in VO x /CeO 2 catalysts improved the catalysts efficiency by increasing oxygen vacancies.

Milk processing industry produced in large amounts wastewater with high pH, temperature and toxic matters. These effluents can exhibit serious environmental problems and public health concerns if improperly disposed. In this present study, an attempt has been made to investigate the efficiency of combined treatment for milk processing industry wastewater. Advanced oxidation process used as primary treatment where as biological process is applied as post treatment to degrade the toxic matters. Parameters affecting the combined process on the percentage removal of turbidity and chemical oxygen (COD) demand were studied in detail. Under the optimum conditions, 93 % of turbidity and 97 % of COD were removed. These results indicated that the proposed technique could be used to degrade the maximum turbidity and chemical oxygen demand from milk processing industry wastewater.

The bulk and supported Ni 2 P catalysts (Ni 2 P/γ-Al 2 O 3 and Ni 2 P/MCM-41) were facile prepared by using nickel metal as nickel source via thermal treatment of hypophosphite in a separated reactor. The thermal decomposition behaviors of sodium hypophosphite were studied by online mass spectra. The effects of atmosphere, temperature, reaction time, and P/Ni atomic ratio on the as-prepared Ni 2 P catalysts were investigated. The Ni 2 P catalysts can also be obtained by using NiCl 2 as nickel source but not for NiO. Since the nickel source is nickel metal and Ni 2 P catalysts were prepared in a separated reactor, the as-prepared Ni 2 P catalysts from Ni 0 can be directly used without further purification, but the as-synthesized Ni 2 P catalyst from NiCl 2 source should be further treated to remove the residues (such as Cl – ) before use. As the active species for hydrodenitrogenation (HDN), Ni 2 P shows much higher activity than Ni 0 . For hydrodearomatization (HDA), Ni 2 P/MCM-41 shows much lower activity than Ni/MCM-41 but much better resistance to S-containing compounds in hydrogenation of naphthalene. The mechanism for synthesizing Ni 2 P catalysts with this facile method is proposed by online mass spectra.

This present study focuses on the evaluation of the effectiveness and the feasibility of a combined treatment between the electrocoagulation (EC) and the adsorption on an activated carbon in grains (GAC) in a continuous mode. The peculiarity of this work is that the experiments are conducted with real wastewater from an industrial dairy. This combined treatment first required an optimization of the EC followed by an adsorption. For each of these techniques, different influential operating parameters such as the current density, the reaction time, the GAC dose, the initial turbidity of water … etc., have been studied. The Turbidity and the COD have been continuously analyzed, while the phosphorus, the BOD 5 , TSS, nitrogen and the grease have been punctually analyzed, and this happened before and after the water treatment. The EC adsorption coupling results have shown that the addition of an appropriate dose of GAC (2 gL −1 ) in a separate column, increases the effectiveness of treatment; more than 98 % of reduction for the COD, the BOD 5 , the turbidity and the greases. A mechanism explaining the phenomena which are involved in this combined treatment is proposed. On the basis of these results of efficiency, speed, low operational cost (~ 3 $m −3 of the treated water), and in comparison with the EC used alone, the EC coupling/the adsorption GAC, could be recommended as a treatment of separation for waters at a high load in organic pollutants.

In the present study, the mass transfer performance of CO 2 absorption into 1-dimethylamino-2-propanol (1DMA2P) as a novel amino alcohol solvent has been theoretically investigated in a split-flow absorber-stripper unit. The mass transfer performance has been presented in terms of CO 2 absorption flux and overall mass transfer coefficient (K G a v ) by simultaneous considering of chemical reactions and mass transfer phenomenon. The developed comprehensive mathematical model has been validated based on related experimental data in literature. The impact of main operation parameters including liquid feed temperature, amine concentration, liquid velocity and CO 2 loading were evaluated. The presented results indicated that increasing the liquid feed temperature, amine concentration and liquid flow rate improves the overall mass transfer coefficient. Also, the CO 2 absorption performance of conventional and alternative amines such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), methyldiethanolamine (MDEA), piperazine (PZ), 4-(diethylamino)-2-butanol (DEAB) and 1DMA2P have been investigated and compared in order to provide guidelines about effective screening of solvents. The modeling results indicated that the K G a v for CO 2 absorption into different solution can be ranked as follows: PZ>MEA>DEA>DEAB>1DMA2P>MDEA>TEA.

A comprehensive study of gas-solids flow behaviors was conducted in a novel multi-stage circulating fluidized bed (MCFB). Experiments were carried out in a cold model apparatus (a jetting fluidized bed, JFB, of 0.3 m diameter and 1.95 m tall, a riser of 0.15 m diameter and 12 m tall) at different elevated pressure, solids circulation rates and gas velocities. Geldart group B polystyrene particles of 400 μm in diameter and 1020 kg/m 3 in density were used as bed materials. The characteristic of L-valve, axial and radial distributions of solids holdup were systematically tested at elevated pressures by pressure transducers with the frequency of 100 Hz and model PC6M of the optical fiber probes. Operating the L-valve at elevated pressure needs less cross-section average gas velocity compared to that at atmospheric pressure. Experimental results showed that under elevated pressure and high solids flow rate, the MCFB could more easily couple JFB with a riser, where the solids that entered could form three-level step-by-step supplement entrainment and multi-flow regimes formed. Besides, increasing operating pressure led to a higher the apparent solids holdup and local solids holdup. The local solids profiles behaved less uniform distribution at elevated pressure due to decreasing the gas velocity.