No abstract

The production of syngas via carbon dioxide reforming or dry methane reforming (DMR) was studied in the present study. To reduce pressure drop and improve the performance, the reaction was carried out over a 10%Ni/Al2O3-MgO catalyst in a wall-coated monolith reactor at about 600°C, atmospheric pressure. The monolith reactor comprised of 37 circular flow channels of 3-mm-diameter. The reactant gases i.e. CH4and CO2at stoichiometric molar ratio of 1:2 was fed into the reactor at the volumetric flow rate of 450, 600 and 750 mL/min corresponding to various gas space velocities (GSV) i.e. 0.57, 0.76, and 0.96 s-1, respectively. Under 24-hr continuous operations, the stability of system could be sustained and the deactivation by carbon deposition was not observed. The experimental results did show that the conversion of methane depended upon the GSV i.e. the %CH4conversion were 50, 45 and 40% for the GSV of 0.57, 0.76, and 0.96 s-1, respectively. In addition, the %H2yield, %H2selectivity, %CO yield, %CO selectivity also depended on the feeding rate and so affected the performance of the wall-coated monolith reactor as a reformer.

Calciner was one of the cement production unit that used momentum, heat, mass distribution and chemical reaction to change calcium carbonate into calcium oxide. One of the important processes was fluid flow. Thus, the computational fluid dynamic was used to predict the flow behavior in the calciner. Regarding gas hydrodynamics, the Navier-Stokes equations were applied along with all practical operating conditions. The simulation results showed that both sides of calciner had the same velocity. High velocity was originated from decreasing of flow area. The velocity in the conjunction zone between TAD and Kiln had high unsteady velocity distribution but, in the higher level, the velocity approached a steady state. This simulation model could be used as a preliminary data in order to predict the temperature distribution.

Water pollution is a serious problem affecting the quality of life and environment. Wastewater treatment is necessary for solving this problem. A bubble column or bubble gas reactor is one of the most widely used in the chemical industries. Volatile organic compounds can be absorbed via gas bubbles in the column. Furthermore, the advantage of the bubble column is highly mass transfer and heat transfer rates. The performance of bubble column depends on bubble size, flow regime, gas hold-up and operating conditions i.e., pressure and temperature. This research focused on hot air bubbles to remove volatile solvents in the solution. CFD simulation was used to study the temperature distribution of gas bubbles within the bubble column. The experiments were carried out to reduce the volatile solvents in contaminated solution using hot air bubbles. The simulation results can be used to predict the performance of the bubble column and the optimal operating conditions for laboratory or industrial scale.

Cooling towers are necessary units used to cool down hot water from industrial processes. These units use high air volume metric flow rate and make up water. These are the disadvantages of using cooling towers. This research applied bubbling technique to cool down hot water. The bubble column was used in this study at different air flow rate. Hot water filled in the column was set at 40°C. Water loss and the reduction of temperature of water were observed. The results showed that the highest evaporation rate of water and the shortest of bubbling time were observed at the highest air flow rate. On the other hand, the lowest amount of air used was observed at the lowest of air flow rate which is the optimum condition of this study. In addition, the rate of heat transfer increases when the turbulent flow in the bubble column was formed.