A Novel Dual-Membranes WGS Reactor with Palladium Alloy and Polyvinyl Alcohol Membranes for Enhanced Hydrogen Recovery

A novel membrane reactor concept including palladium alloy membrane (selective to H2) and polyvinyl alcohol membrane (selective to CO2) is proposed for water gas shift reaction. The mathematical model of the reactor is developed for two reactor schemes, namely plug dual-membrane reactor (PDMR) and CSTR dual-membrane reactor (CDMR) with uni-dimensional and non-isothermal conditions. A comparison between PDMR and palladium alloy membrane reactor (PAMR) showed that PDMR volume becomes 30 % less than PAMR with 20 bar increase in feed pressure. Then the effect of Damkholer number, feed composition, and feed pressure on hydrogen recovery and CO conversion for PDMR and CDMR has been studied. Under the same operating conditions, CO conversion in PDMR is 10 % more than CDMR while its temperature decreases. The new proposed reactor configuration could pave the way for simultaneous production of hydrogen, increased CO conversion, and CO2 separation on an industrial scale

Application of functionalized nanofluid in thermosyphon

A water-based functionalized nanofluid was made by surface functionalizing the ordinary silica nanoparticles. The functionalized nanofluid can keep long-term stability. and no sedimentation was observed. The functionalized nanofluid as the working fluid is applied in a thermosyphon to understand the effect of this special nanofluid on the thermal performance of the thermosyphon. The experiment was carried out under steady operating pressures. The same work was also explored for traditional nanofluid (consisting of water and the same silica nanoparticles without functionalization) for comparison. Results indicate that a porous deposition layer exists on the heated surface of the evaporator during the operating process using traditional nanofluid; however, no coating layer exists for functionalized nanofluid. Functionalized nanofluid can enhance the evaporating heat transfer coefficient, while it has generally no effect on the maximum heat flux. Traditional nanofluid deteriorates the evaporating heat transfer coefficient but enhances the maximum heat flux. The existence of the deposition layer affects mainly the thermal performance, and no meaningful nanofluid effect is found in the present study

Preliminary experimental investigation of a natural gas-fired ORC-based micro-CHP system for residential buildings

The continual increases in energy demand and greenhouse gas emissions, call for efficient use of energy resources. Decentralized combined heat and power (CHP) technology provides an alternative for the world to meet and solve energy-related problems including energy shortages, energy supply security, emission control and conservation of energy. This paper presents the preliminary results of an experimental investigation of a natural gas-fired micro-CHP system for residential buildings based on an organic Rankine cycle (ORC). Isopentane was used as the ORC working fluid in consideration of several criteria including its environmentally-friendly characteristics. Experiments were conducted to evaluate the performance of the developed system at different heat source temperatures of nominally 85, 80, 75, 70, and 65 C. The maximum electrical power output of 77.4 W was generated at heating water entry temperature of 84.1 C, corresponding to net cycle electrical efficiency of 1.66%. Further work will be done with a view to increasing the cycle electrical efficiency by using more efficient components, in particular the expander and generator

containing Non-electrolytes

Abstract: In this study, the antisolvent crystallization system containing sodium chloride as solute, water as primary solvent and ethanol as the antisolvent was considered. At first there was a saturated solution of water-NaCl, by gradual addition of ethanol in a specific rate, the solubility of NaCl decreases. A thermodynamic model which can predict the behavior of the aqueous salt systems containing non-electrolytes was applied in this study. This model consists of a Gibbs energy function, which combines a Debye-Hückel term with the standard UNIQUAC model. Using the Extended UNIQUAC model for the purpose of thermodynamic modeling, the solubility of NaCl in the water-ethanol mixture in different compositions with an acceptable error was calculated. The model parameters including volume, surface area and binary interaction parameters were modified by comparing the experimental and theoretical data of NaCl solubility in water-ethanol mixture. Afterwards, this thermodynamic solubility model was introduced to the kinetic modeling of antisolvent crystallization process using Population Balance Equation. Using supersaturation for the calculation of the nucleation and the crystal growth rates, crystal size distribution and the volume mean of crystals were determined by the numerical solution to the PBE implementing Discretization technique. In order to evaluate the model accuracy, antisolvent addition rates were changed and the results were compared with the experimental data, the results appeared justifiable