Numerical Study on Mechanism of Nanoparticle Formation in High Temperature Reactor

Properties of nanoparticles are size-dependent, therefore nucleation and growth of particle is often difficult. The population balance model has been developed to study the mechanism of nanoparticles formation in high temperature reactor. Processes responsible for particle formation and growth are considered by homogeneous nucleation, condensation and Brownian coagulation. Parameters such as temperature, residence time and reactant concentrations influencing particle size are investigated. The population balance model is the dynamic model that describes the evolution of the aerosol size distribution with time. The method of moments was used to solve the dynamic equation under the assumption of log-normal size distribution. The model was validated with existing model

Simulation and control of nanoparticle size distribution in a high temperature reactor

This work focuses on the modeling, simulation and control of particle size distribution (PSD) during nanoparticle growth with the simultaneous chemical reaction, nucleation, condensation, coagulation and convective transport in a high temperature reactor. Firstly, a model known as population balance model was derived. This model describes the formation of particles via nucleation and growth. Mass and energy balances in the reactor were presented in order to study the effect of particle size distribution for each reaction mechanisms on the reactor dynamics, as well as the evolution of the concentrations of species and temperature of the continuous phase. The models were simulated to see whether the reduced population balance can be used to control the particle size distribution in the high temperature reactor. The simulation results from the above model demonstrated that the reduced population balance can be effectively used to control the PSD. The proposed method “which is the application of reduced population balance model” shows that there is some dependence of the average particle diameter on the wall temperature and the model can thus be used as a basis to synthesize a feedback controller where the manipulated variable is the wall temperature of the reactor and the control variable is the average particle diameter at the outlet of the reactor. The infl uence of disturbances on the average particle diameter was investigated and controlled to its new desired set point which is 1400nm using the proportional-integral-derivative controllers (PID controllers). The proposed model was used to control nanoparticle size distribution at the outlet of the reactor

Rheological Properties of Polymers: Structure and Morphology of Molten Polymer Blends

The article reviews a brief literature on the rheological properties of polymer melts and blends. Experimental results on polymer blends are summarized. Technically, vital types of multi-phase polymers such as compounds and blends are discussed. The importance of the rheological properties of polymer mixtures in the development of the phase structure is discussed. And the importance of considering the stress and/or strain history of a material sample in a rheological investigation is discussed. Finally, the outlook on the past, present and future developments in the field of polymer rheology are given. The review concludes with a brief discussion on the opportunities and challenges in the field of polymer blends and blend rheology

The properties and the effect of operating parameters on nickel plating (review)

The energy required in an electroplating process and the material costs are important considerations in product manufacturing. The most important plating criteria, however, are quality and the uniformity of the deposited metals. The nickel plating process is used extensively for decorative, engineering, and electroforming purposes. Because of the appearance and other properties of the electrodeposited material, nickel deposition can be varied, over a wide range, by controlling the composition and the operating parameters of the plating solution. Decorative applications account for about 80% of the nickel consumed in plating; 20% is consumed for engineering and electroforming purposes. Autocatalytic (electroless) nickel plating processes are commercially important but are outside the scope of this review. In this review, the basic facts of nickel electroplating processes, thickness test and methods, are discussed. The properties of nickel and the different effects of the operating parameters on nickel plating, together with the simulation and design tools, are also reviewed. Simulation tools can help to obtain better plating results. Non-destructive techniques to evaluate the coatings on a microstructural and the technical evaluation with TEM, SEM, XRD and other techniques were also reviewed

Porous and fractal analysis on the permeability of nanofiltration membranes for the removal of metal ions

Porous and fractal analysis on the permeability of nanofiltration membranes was investigated for the removal of metal ions. The permeability of a porous membranes used in wastewater treatment is strongly depended on its local geometry and connectivity, the size distribution of the pores available for flow. Fouling studies with two different membranes at three different pHs were carried out with manganese and magnesium. It was shown that the tighter membrane was less rougher and less fouled compared with the rougher membrane. NF90-2450 showed the highest degree of fouling. The X-ray diffraction showed that NF90-2540 consist of a pronounced diamond at the angle of 45 �C which was responsible for porosity. The threshold images were obtained from the scanning electron microscopy images with the use of Image J software confirmed that NF90-2540 has higher percentage porosity when compared with the percentage porosity of NF1540-3. An evaluation of the relationships between porosity and permeability for the fractal analysis by a box counting was done. The evaluation also confirmed that the lower fractal dimension corresponds to a lower value of porosity. The higher the pH, the lower the fractal dimension of the used membranes due to the blockage of pores. A higher value of fractal dimension of the used membrane at a lower pH corresponds to a lower rejection of the metal ions

Sustaining the shelf life of fresh food in cold chain – A burden on the environment

AbstractEnergy consumption in cold chains has been predicted to rise significantly in view of the increasing world population. Of critical attention is the increasing number of road transport refrigeration which is highly gaining enormous ground globally. In view of the fact that 40% of all foods require refrigeration, 15% of world fossil fuel energy is used in food transport refrigeration. This concern necessitates this study to examine cold chain system with the emphasis on the impact of energy consumption in sustaining the shelf life of fresh food. As the world continues to battle with the global warming occasioned by emission of carbon dioxide from fossil fuel, this study identifies alternative means of saving energy in food transportation system through minimizing energy consumption in diesel engine driven vapour compression system. Preserving perishable fresh food (mainly vegetable) under sub-zero weather is another debacle the authors envisaged in the quest to reduce fossil fuel consumption. This process requires heating the mechanical refrigeration unit in a reverse-cycle to raise the temperature at 0°C which may further result in more energy demand. The conclusion drawn from this study could be useful in re-designing food transport system for optimal energy saving

Numerical Simulation for Nanoparticle Growth in Flame Reactor and Control of Nanoparticles

We review the models and numerical methods used in flame reactor for the modeling and simulation of nanoparticle. And we also review the control of nanoparticle size distribution, some nonlinear control strategies were looked into. A general model in which nanoparticles form in gas phase and grow through chemical reaction, nucleation, condensation and coagulation is discussed. Particles dispersed in a fluid move randomly, due to Brownian motion, and, along their trajectories, they collide with each other. The model is formulated in terms of a detailed population balance which describes how aerosol size distribution evolves with time. For this population balance models a number of different numerical approaches exist. We reviewed sectional, finite element and Monte Carlo methods, method of moment

Modeling and Simulation of Hydrogen Storage Device for Fuel Cell Plant

The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel cell are summarized. Mathematical modeling equations involved are also stated. The effect of various operating parameters such as temperature, concentration, viscosity, thermal conductivity and time on the gas is also verified. The importance of various simulation software with reference to their major functions is also identified. The review concludes on the opportunities and challenges with the use of hydrogen as an alternative renewable energ