Abstract: In order to respond the policy decision of non-nuclear homes, Tai Power Company (TPC) will provide the decommissioning project of Kuosheng Nuclear power plant (KSNPP) to meet the regulatory requirement in near future. In this study, the computational fluid dynamics (CFD) methodology has been employed to develop a flow prediction model for boiling water reactor (BWR) with upper pool under decommissioning stage. The model can be utilized to investigate the flow behavior as the vessel combined with upper pool and continuity cooling system. At normal operating condition, different parameters are obtained for the full fluid area, including velocity, mass flow, and mixing phenomenon in the reactor pressure vessel (RPV) and upper pool. Through the efforts of the study, an integrated simulation model will be developed for flow field analysis of decommissioning KSNPP under normal operating condition. It can be expected that a basis result for future analysis application of TPC can be provide from this study.
Abstract: Steam injection is the most suitable of Enhanced Oil Recovery (EOR) methods to recover high viscosity oil. This is due to the capabilities of steam to reduce oil viscosity and increase the sweep capability of oil from the injection well toward the production well. Oil operating conditions in production should be match well with the operating condition target at the bottom of the production well. It is influenced by oil properties and reservoir rock properties. Hence, the operating condition should be optimized. Optimization requires three components i.e., objective function, model, and optimization technique. In this paper, the objective function is to obtain the optimum operating condition at the production well. The model was built using Darcy equation and mass-energy balance. The optimization technique utilizes Duelist Algorithm due to the effectiveness of its algorithm to obtain the desirable optimization results at the optimum operating condition.
Abstract: Alumina supported platinum and tin catalysts with different loadings of Pt and Sn were prepared and characterized by low temperature N2 adsorption/desorption, H2-temperature programed reduction and CO pulse chemisorption. Pt and Sn below 1% loading were suitable for acetic acid hydrogenation. The best performance over 0.75Pt1Sn/Al2O3 can reach 87.55% conversion of acetic acid and 47.39% selectivity of ethanol. The operating conditions of acetic acid hydrogenation over 1Pt1Sn/Al2O3 were investigated. High reaction temperature can enhance the conversion of acetic acid, but it decreased total selectivity of ethanol and acetyl acetate. High pressure and low weight hourly space velocity were beneficial to both conversion of acetic acid and selectivity to ethanol.
Abstract: Radial profiles of particle velocities were investigated
in a 6.1m high methanol-to-olefins cold model experimental device
using a TSI laser Doppler velocimeter. The effect of axial height on
flow development was not obvious in fully developed region under the
same operating condition. Superficial gas velocity and solid
circulating rate had significant influence on particle velocity in the
center region of the riser. Besides, comparisons among rising,
descending and average particle velocity were conducted. The particle
average velocity was similar to the rising particle velocity and higher
than the descending particle velocity in radial locations except the wall
region of riser.
Abstract: PH, temperature and time of extraction of each stage,
agitation speed and delay time between stages effect on efficiency of
zinc extraction from concentrate. In this research, efficiency of zinc
extraction was predicted as a function of mentioned variable by
artificial neural networks (ANN). ANN with different layer was
employed and the result show that the networks with 8 neurons in
hidden layer has good agreement with experimental data.
Abstract: Gold coated silica core nanoparticles have an optical
response dictated by the plasmon resonance. The wavelength at
which the resonance occurs depends on the core and shell sizes,
allowing nanoshells to be tailored for particular applications. The
purposes of this study was to synthesize and use different
concentration of gold nanoshells as exogenous material for skin
tissue soldering and also to examine the effect of laser soldering
parameters on the properties of repaired skin. Two mixtures of
albumin solder and different concentration of gold nanoshells were
prepared. A full thickness incision of 2×20 mm2 was made on the
surface and after addition of mixtures it was irradiated by an 810nm
diode laser at different power densities. The changes of tensile
strength σt due to temperature rise, number of scan (Ns), and scan
velocity (Vs) were investigated. The results showed at constant laser
power density (I), σt of repaired incisions increases by increasing the
concentration of gold nanoshells, Ns and decreasing Vs. It is therefore
important to consider the trade off between the scan velocity and the
surface temperature for achieving an optimum operating condition. In
our case this corresponds to σt =1610 gr/cm2 at I~ 60 Wcm-2, T ~
65ºC, Ns =10 and Vs=0.2mms-1.
Abstract: Laser soldering is based on applying some soldering material (albumin) onto the approximated edges of the cut and heating the solder (and the underlying tissues) by a laser beam. Endogenous and exogenous materials such as indocyanine green (ICG) are often added to solders to enhance light absorption. Gold nanoshells are new materials which have an optical response dictated by the plasmon resonance. The wavelength at which the resonance occurs depends on the core and shell sizes, allowing nanoshells to be tailored for particular applications. The purposes of this study was use combination of ICG and different concentration of gold nanoshells for skin tissue soldering and also to examine the effect of laser soldering parameters on the properties of repaired skin. Two mixtures of albumin solder and different combinations of ICG and gold nanoshells were prepared. A full thickness incision of 2×20 mm2 was made on the surface and after addition of mixtures it was irradiated by an 810nm diode laser at different power densities. The changes of tensile strength σt due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. The results showed at constant laser power density (I), σt of repaired incisions increases by increasing the concentration of gold nanoshells in solder, Ns and decreasing Vs. It is therefore important to consider the tradeoff between the scan velocity and the surface temperature for achieving an optimum operating condition. In our case this corresponds to σt =1800 gr/cm2 at I~ 47 Wcm-2, T ~ 85ºC, Ns =10 and Vs=0.3mms-1.
Abstract: With the growth of electricity generation from gas
energy gas pipeline reliability can substantially impact the electric
generation. A physical disruption to pipeline or to a compressor
station can interrupt the flow of gas or reduce the pressure and lead
to loss of multiple gas-fired electric generators, which could
dramatically reduce the supplied power and threaten the power
system security. Gas pressure drops during peak loading time on
pipeline system, is a common problem in network with no enough
transportation capacity which limits gas transportation and causes
many problem for thermal domain power systems in supplying their
demand. For a feasible generation scheduling planning in networks
with no sufficient gas transportation capacity, it is required to
consider gas pipeline constraints in solving the optimization problem
and evaluate the impacts of gas consumption in power plants on gas
pipelines operating condition. This paper studies about operating of
gas fired power plants in critical conditions when the demand of gas
and electricity peak together. An integrated model of gas and electric
model is used to consider the gas pipeline constraints in the economic
dispatch problem of gas-fueled thermal generator units.
Abstract: Capacity and efficiency of any refrigerating system
diminish rapidly as the difference between the evaporating and
condensing temperature is increased by reduction in the evaporator
temperature. The single stage vapour compression refrigeration
system is limited to an evaporator temperature of -40 0C. Below
temperature of -40 0C the either cascade refrigeration system or multi
stage vapour compression system is employed. Present work
describes thermal design of main three heat exchangers namely
condenser (HTS), cascade condenser and evaporator (LTS) of
R404A-R508B and R410A-R23 cascade refrigeration system. Heat
transfer area of condenser (HTS), cascade condenser and evaporator
(LTS) for both systems have been compared and the effect of
condensing and evaporating temperature on heat-transfer area for
both systems have been studied under same operating condition. The
results shows that the required heat-transfer area of condenser and
cascade condenser for R410A-R23 cascade system is lower than the
R404A-R508B cascade system but heat transfer area of evaporator is
similar for both the system. The heat transfer area of condenser and
cascade condenser decreases with increase in condensing temperature
(Tc), whereas the heat transfer area of cascade condenser and
evaporator increases with increase in evaporating temperature (Te).
Abstract: Capacity and efficiency of any refrigerating system
diminish rapidly as the difference between the evaporating and
condensing temperature is increased by a reduction in the evaporator
temperature. The single stage vapour compression refrigeration
system using various refrigerants are limited to an evaporator
temperature of -40 0C. Below temperature of -40 0C the either
cascade refrigeration system or multi stage vapour compression
system is employed. Present work describes thermal design of
condenser (HTS), cascade condenser and evaporator (LTS) of
R404A-R508B and R410A-R23 cascade refrigeration system. Heat
transfer area of condenser, cascade condenser and evaporator for
both systems are compared and the effect of condenser and
evaporator temperature on heat-transfer area for both systems is
studied under same operating condition. The results shows that the
required heat-transfer area of condenser and cascade condenser for
R410A-R23 cascade system is lower than the R404A-R508B cascade
system but heat transfer area of evaporator is similar for both the
system. The heat transfer area of condenser and cascade condenser
decreases with increase in condenser temperature (Tc), whereas the
heat transfer area of cascade condenser and evaporator increases with
increase in evaporator temperature (Te).