Hydrogen Sulfide Adsorption from Natural Gas Using Silver-Modified 13X Molecular Sieve.

The removal of hydrogen sulfide from natural gas and other gases such as biogas, refinery gases, and coal gas is required because it is toxic and corrosive, even in traces. Zeolites are widely used in the removal of H2S from the abovementioned gases. In this work, we prepared an Ag-exchanged 13X molecular sieve by using different concentrations of AgNO3 to increase its adsorption properties. XRD, SEM, and BET techniques were used to characterize samples. To determine the adsorption properties of each of the samples, a laboratory setup with a fixed-bed adsorber was utilized. The adsorption capacity of modified 13X increased when the molar concentration of AgNO3 increased from 0.02 M to 0.05 M. However, the breakthrough time was attained quicker at a high molar concentration of 0.1 M AgNO3, indicating a low adsorption capacity. When compared to unmodified 13X, the adsorption capacity of AgII-13X increased by about 50 times. The results of this study suggest that the silver-modified 13X molecular sieve is highly effective at extracting H2S from natural gas.

A Simple Densimetric Method to Determine Saturation Temperature of Aqueous Potassium Chloride Solution.

The precise control of crystallization is a key issue in providing a high quality crystalline product. It has to be achieved by, among other means, a proper choice of the solution processing temperature, which is determined on the basis of the metastable zone width and type of solubility curve. In this article experimental data for potassium chloride solution density, as a function of temperature and its correlation in the range from under- to supersaturation, are reported for solution concentrations between 24.62 % w/w and 31.84 % w/w. As could be expected in the case of undersaturated solutions and low supersaturation, the temperature dependence of density for solutions of different saturation may be described by a linear equation within the investigated range of concentrations. It was also proved that for the undersaturation range there exists a pole point, which allows calculation of the saturation temperature, based on the density measured at any temperature.