Atilla Murathan

The relation between wetting efficiency and liquid holdup in packed columns

Liquid holdup and wetting efficiency in packed columns were determined using a tracer method. A new model was developed considering axial dispersion, and analysis was made using the moment technique. The saturated solution of KG was used as an inert tracer and total liquid holdups were determined in the first part of experiments. As an adsorbable tracer, dioxane was utilized in the second part of the work and wetting efficiencies were obtained. Adsorption equilibrium constant was determined by the experiments conducted in a liquid full bed. A model proposed between liquid holdup and wetting efficiency gave good agreement with the experimental results. Axial dispersion effects were also taken into account during the work. It was also shown that axial dispersion of liquid phase should be considered especially in the small scale trickle bed reactors. @KEYWORDS:Packed beds,Wetting efficiency,Liquid holdup,Tracer method,Moment technique,Trickle bed reactors.

Electricity Production from Geothermal Sources by Using Double-Stage Flash System

Abstract Geothermal energy has a big importance among the renewable energy sources. In flash systems, steam quality is increased by flashing geothermal fluid. When suitable conditions exist, second flash can be used, which increases the energy production to a great extent. In double-stage flash system, selection of the first- and second-flash temperatures is very important for effective production. For the resources in Canakkale Tuzla geothermal regions, with an average temperature of 438 K and vapor content about 13%, optimum first- and second-flash temperatures were found to be 393 K and 346 K, respectively. In this study, a computer program was prepared to determine flash temperatures. It was used to find out the optimum flash temperatures which correspond to maximum work. In these calculations, the properties of Canakkale Tuzla geothermal sources in Turkey were taken as a basis.

ESR of Gamma Irradiation Damage Centers in Single Crystals of Some Glutamic Acid Derivatives

Abstract We have observed four radicals in the ESR spectra of y-irradiated single crystals of some glutamic acid derivatives. These radicals, produced by gamma-irradiation, in single crystals of N-Acetyl-L-Glutamic acid, L-Glutamic acid and DL-Glutamic acid hydrochloride were identified as CH3CONH, -C3H5 , -CH, and -NH2 radicals respectively.

Air Oxidation of Aqueous Cyanides in a Countercurrent Fixed Bed Reactor

This study was conducted to discuss the removal of cyanides from water by air oxidation. Experiments were carried out in a countercurrent fixed bed reactor for three different values of temperature, concentration, gas and liquid flow rates. It was operated at pH 12 by using delrin (formaldehyde polymer) as packing material. Effects of some operating parameters on the conversion were studied, and it was observed that the conversion percent increased by increasing temperature and decreasing gas and liquid flow rates. Effect of concentration was not steady. A conversion of 89% was achieved under optimum conditions while it ranges from 44 to 79% at room temperature.

Removal of Cyanides from Water by Air Oxidation in a Cocurrent Downflow Fixed Bed Reactor

A method for removal of cyanides from water is described. The method involves the air oxidation of cyanides in a fixed bed reactor with cocurrent downflow. Effects of parameters such as temperature, concentration, gas and liquid flow rates on the oxidation yield are studied. It was observed that the yield increases by increasing temperature and decreasing gas and liquid flow rates. Altering the concentration had no clear effect on the yield. A yield of 86 % was achieved at high temperature (60°C) while the maximum yield was 68 % at room temperature.

Effects of various parameters on removal of NO2 gases in fixed beds by adsorption on sepiolite

Removal of NO2 gases in fixed beds was investigatedby using brownish, whitish and regenerated whitish sepioliteand perlite as adsorbents. For this purpose, NO2 wasproduced by reaction of copper with nitric acid. The producedgas was mixed with air and the mixture was sent through a fixedbed. Studies were conducted using various gas flow rates,NO2 concentrations, packing sizes and heights of bed.Remaining NO2 within the gas mixture leaving the column,unadsorbed on packing, was further absorbed by passing itthrough a series of washing bottles, filled by a solution ofNaOH. At the end of the study, it was observed that theadsorption capacity of sepiolites, especially whitishsepiolite, was much higher than that of perlite. Additionally,it was seen that its adsorption capacity increased withincreasing bed height, particle size, NO2 concentrationand decreasing gas flow rate.