Papers by Keyword: Humidification

Abstract: In this paper, an experimental work studies the principal operating parameters of a proposed desalination process using air humidification-dehumidification method. The major objective of this work is to determine the humid air behavior through the desalination system. Different operating conditions including the effect of the water temperature at the entry to the humidifier, the ratio of the mass of water to the air, the air/water flow rate, and cooling water at entry the dehumidifier on the desalination performance were studied. The results show that the freshwater increases with increasing the water temperature at the inlet of the humidifier, the ratio of the mass of water to air, and cooling water flow rate in the dehumidifier. Cooling water outlet temperature at the condenser increases with increasing the water temperature at humidifier inlet. Also, it decreases as increasing cooling water flow rate while the ratio of the mass of water to air achieves the highest productivity and gained output ratio (GOR). The achieved mass ratio (MR) is 4.5 and the mass flow rate of air is 0.8 kg/min.

Abstract: In recent decades, Heat and Moisture Exchange (HME) devices have been employed increasingly for short-term use in anaesthesia and long-term use in intensive care units. These devices work as heat exchangers, accumulating the patient’s expired heat and moisture and returning them to the patient during the inhalation phase. Porous matrices obtained from freeze-drying of blends of natural polymers exhibit high open and interconnected porosity and water vapour intake characteristics which make them possible candidates for HME devices. Preliminary tests were conducted on specimens made of gelatine blended with chitosan and treated with a non-toxic cross-linking agent. The tests were carried out in cyclic flow conditions with saturated and dried air. Results show water vapour retention comparable with accepted standards for HME devices.

Abstract: In order to study the effect of dust removal in the electrostatic precipitator under the influence of change of temperature and air moisture of flue gas, the ultrasonic atomization and electrical heating has been adopted for simulated gas to change its air moisture and temperature. The specific resistance of fly ash of fluidized bed boiler, the V-j characteristics of the precipitator model and the efficiency of dust removal has been tested in gas working conditions. The measured results of dust specific resistance shows that: when the temperature of gas at range of 100°C to 150°C, the specific resistance of dust was lower when the air moisture is at 23.73% than at 5.21%, especially when the gas temperature is below 120°C, the specific resistance of dust reduce more,and it can reach the orders of magnitude at10¹⁰Ω·cm when the moisture of 23.73%; then keep the temperature at 150°C and make the moisture increased, the specific resistance of dust is decreased, however it is still more than 10¹¹Ω·cm when the moisture is increased to 23.73%. The measured results of V-j characteristics of the precipitator model shows that: when the moisture keeps at 23.73% and the temperature is below 120°C, the electric field does not occur the phenomenon of anti-corona. The test result of the efficiency of dust removal indicated that: when we make the moisture increased to 23.73% and the gas temperature below 120°C, the efficiency of dust removal shows a significant increase. The results confirmed that we can improve the purification efficiency of high resistivity dust through flue gas humidification and proper temperature maintain.

Abstract: Based on soil structural view, the mechanism of loess structure is analyzed in humidification process. The concept of the loess structure loss is proposed.And quantitatively parameter described the loess structure loss is set up, that is structure loss parameter. And then the influence laws of humidification and loading on loess structure loss are discussed. The results show that structure loss parameters is increasing with the increase of the humidification water content. The moistening collapsibility has a good linear relationship with loess structure loss parameters.

Abstract: The performance of Proton Exchange Membrane Fuel Cell (PEMFC) is known to be influenced by different operating conditions such as temperature, pressure, and humidification of the reactant gases. Especially, the humidification is essential for the electrolysis and performance enhancement of PEMFC, because the proton conductivity depends on the hydration of proton exchange membrane. In this study, the humidification experiment has been done concerning ON/OFF control of the humidification for PEMFC, by using of the bubble humidifiers which are usually difficult to approximation control the humidity. Also, in order to verify the dew condensation, the visualization experiment has been done at a flow channel of PEMFC stack. As the results, it is possible to approximation control the humidity by using of the solenoid on/off valve in the bubble humidifier. The dew condensation is also verified through such experiment. The problems, such as the approximation control of humidity and dew condensation, were then resolved in such a useful manner.

Abstract: The matric suction has very important influence on the characteristics of unsaturated sand; and it is closely relevant to density. In order to discuss the relationship among the matric suction, water content and dry density, the matric suction of the eolian sand were measured in laboratory. The soil-water characteristics curves for unsaturated eolian sand with different dry densities are obtained. The test results show that the variation tendency of soil-water characteristics curves has been corresponding to the different densities.

Abstract: A humidification approach was employed by using spraying mist on the roving before the back rollers of the spinning frame to improve the quality of the hemp/cotton blended yarn. The yarn performance after was investigated. The investigation showed that the evenness, hairiness, tenacity of the yarn was improved by using the humidification technique. When the humidification reached 250mL/h, the spinning process was adversely affected and quality of yarn decreased.

Abstract: An experimental and numerical study of polymer electrolyte membrane fuel cell (PEMFC) is presented and compared with the experimental data to investigate the effects of pressure gradient, flow rate, humidification and supplied oxidant type for the practical application. The membrane and electrolyte assembly (MEA) materials are implemented by double-tied catalyst layers. A single-phase two-dimensional steady-state model is is implemented for the numerical analysis. Testing condition is fixed at 60sccm and 70°C in anode and cathode, respectively. It is found that the performance of PEMFC depend highly on the conditions as gas pressure, temperature, thickness, supplied oxidant type (Oxygen/Air) as well as humidification. The results show that the humidification effect enhances the performance more than 20% and the pure oxygen gas as fuel improves current density more than 25% compared to ambient air suppliance as oxidant.