The purpose of this study is to efficiently produce hydrogen gas from saccharide using 27.12 MHz radiofrequency (RF) in-liquid plasma with and without ultrasonic irradiation. The experiments were conducted adopting two different ultrasonic frequencies, one from a 29 kHz horn-type ultrasonic transducer and the other from a 1.6 MHz piezoelectric transducer. The glucose solution and cellulose suspension concentrations were varied from 0.5 wt% to 50 wt% and 0.5 wt% to 20 wt% respectively. Hydrogen gas was then produced by the decomposition of the glucose solution and cellulose suspension by RF in-liquid plasma with and without ultrasonic irradiation. The hydrogen production rate from glucose solution with ultrasonic irradiation applied was greater than that without ultrasonic irradiation. However, no hydrogen production rate enhancement was observed from decomposition of cellulose suspension with ultrasonic irradiation applied. Ultrasonic atomization and agitation enhanced the chemical reaction of nonvolatile glucose in in-liquid plasma. The increase of the gas production rate was caused by the direct decomposition of the glucose by the plasma due to the atomized glucose molecules being fed into the plasma in a bubble. In addition, by using a high-speed camera, it was clarified that acoustic streaming occurred when a 1.6 MHz piezoelectric transducer was used in the experiment.
Due to the high energy consumption and decreasing oil supply, the alternative energy sources such as biomass and agricultural waste can be considered as the main sources of energy in the future. Currently, one of the technologies to convert such biomass to more valuable products is biomass-to-liquid process. However, acid gases like CO2 and H2S are produced as intermediates causing the decrease in product heating values, operational problems, corrosion, and environmental concern. Therefore, the objective of this work is to simulate the absorption process of acid-gas cleaning by using various solutions at different operating conditions in order to meet the requirement. The results show that MDEA has higher performance to remove both gases compared to other chemicals. Furthermore, at 0.9 MPa and 25 °C, the treated gas provides 3.19 vol% CO2 and 27.7 ppb of H2S for MEA, 2.13 % CO2 and 0.02 ppb of H2S for MDEA and 7.45 % CO2 and 1.12*10-6 ppb of H2S for Selexol. Moreover, the liquid flow rate, solution concentration and effects of temperature and pressure are also investigated for the optimal design of the absorption column.
Technology of solar distillation technology is well established. However, application of locally available material in a manner techno-economically conducive to distillation has been always a point of investigation. In this paper, design, development and experimental results of four sloped pyramid shape top cover solar still is presented. The principal objective has been to use locally available foams to increase the distillate output. Experiments are carried out under the climatic conditions of Coimbatore, India (11° North, 77° East) under typical clear sky days. The system designed and developed is operated into two modes, (i) with thin water layer on the absorber and (ii) with black colored foam of varying dimensions are used in basin bed. The stainless steel basin of length 98.6 cm, breath 98.6 cm and 12.5 cm is used for water storage. An increase in condensate due to capillary rise is observed. System was further evaluated by recording variation in foam temperature, cover temperature, air temperature, ambient temperature and distillate output.