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Flare gas recovery is one of the most attractive methods to improve energy efficiency in oil refineries to decrease greenhouse gas emissions. The recovered gas is used to feed refinery processes, granting advantages in terms of fuel economy and flare stress. This paper presents the results obtained by a feasibility study of a flare gas recovery system in a real refinery; the work focused on: i) the...
This study examines the oil price risk exposure of U.S. financial and non-financial industries over the period of January 1983 to March 2015. We include the oil price risk factor into the Fama and French [17] five-factor asset pricing model and identify the structural breaks in the equity returns using the test created by Bai and Perron [4]. The oil price risk exposures of financial and non-financial...
Ionic liquid added PVA (poly (vinyl alcohol))-based ion conductors are investigated for EDLCs (Electric Double Layer Capacitors) using electrochemical measurements. Polymer electrolytes incorporated with ammonium acetate (CH3COONH4) as salt and 1-butyl-3-methylimidazolium iodide (BmImI) as the ionic liquid exhibit VTF (Vogel–Tamman–Fulcher) relationship, which is associated with free volume theory...
A novel wave energy extraction method, based on the PTO (Power Take-Off) mechanism, is developed by utilizing an array of buoys connected with a flexible runway. Hydrodynamic interactions among the buoys are analyzed using an exact algebraic method based on linear wave theory in the frequency domain. A parametric governing equation of compounded wave energy converter referred to as a wave farm is...
Fouling is a crucial problem in refinery HEN (heat exchanger network) that reduces heat transfer and affects regular production. The conventional way to mitigate fouling is cleaning heat exchanger regularly or improving operation conditions, but simultaneous consideration of the two methods is rare. This paper presents a combined approach for mitigating fouling in HEN by optimizing operation condition...
This reported work investigates the sensitivities of spray and soot developments to the change of thermo-physical properties for coconut and soybean methyl esters, using two-dimensional computational fluid dynamics fuel spray modelling. The choice of test fuels made was due to their contrasting saturation-unsaturation compositions. The sensitivity analyses for non-reacting and reacting sprays were...
The paper presents an investigation into the energy performance of a novel irregular heat and mass exchanger for dew point cooling which, compared to the existing flat-plate heat exchangers, removed the use of the channel supporting guides and implemented the corrugated heat transfer surface, thus expecting to achieve the reduced air flow resistance, increased heat transfer area, and improved energy...
The smart metering infrastructure in Sweden allows electricity providers to offer electricity RTP (real time pricing) to homeowners, together with other dynamic pricing contracts across the country. These contracts are supposed to encourage users to shift power consumption during peak hours to help balance the load in the power system. Of all the available contracts in Sweden, monthly-average price...
Miller cycle is applied to improve performance and emission characteristics of a gas engine. There are different types of Miller cycle concept utilization through variation of valve timing either by early intake valve closure or late intake valve closure. In this study finite-volume method is used to analyse the performance and emission characteristics of a four-stroke 12-cylinder turbocharged Miller...
One of attracting concepts has been the use of Turbosail principle to produce lift from aspirated cylinders with flap in various engineering applications. The Emerging of the Turbosail principle in wind turbine technology is promising to develop and to design innovative devices. The objective of this project paper is to develop an efficient numerical code, for the prediction of the aerodynamic characteristics...
Accurate models of PEM (proton exchange membrane) fuel cells are of great significance for the analysis and the control for power generation. We present a new semi-empirical model to predict the voltage outputs of PEM fuel cell stacks. We also introduce a new estimation method, called AC-POA (aging and challenging P systems based optimization algorithm) allowing deriving the parameters of the semi-empirical...
Using abandoned oil wells for geothermal power generation can relieve energy problem, save drilling cost, and govern the pollution caused by the residual oil of the abandoned oil wells. In this paper, a novel method for enhancing the geothermal utilization efficiency by developing thermal reservoirs is presented. A 2-D thermal reservoirs coupling with 1-D wellbore heat transfer model was set up to...
This study deals with the thermodynamic modeling of biomass Gasifier–SOFC (Solid Oxide Fuel Cell)–GT (Gas Turbine) systems on a small scale (100 kWe). Evaluation of an existing biomass Gasifier–SOFC–GT system shows highest exergy losses in the gasifier, gas turbine and as waste heat. In order to reduce the exergy losses and increase the system's efficiency, improvements are suggested and the effects...
In this paper, a differential evolution based multi-objective optimization algorithm is proposed to optimally size a photovoltaic water pumping system (PVPS). Non-dominated sorting and crowding distance concepts are used to increase the elitism and diversity of the proposed algorithm. The proposed objective function is composed of technical and economic objectives. Loss of load probability is used...
A critical characteristic of most WECs (wave energy converters) is the large peak-to-average power ratio. This poses many challenges to the design of high-efficient PTO (power take-off) systems and, even more importantly, to integrate this form of renewable energy into power grids. The OWC (oscillating water column) WECs are devices whose PTO uses an air turbine as the primary energy converter. Besides...
A thermal evaluation of a R-TW system (room with a Trombe wall) is presented. Hourly climatic data of the coldest and the warmest days of 2014 was used to assess the behavior of the R-TW in two cities of Mexico with cold climate (Huitzilac and Toluca). The simulations were done with an in-house code based on the Finite Volume Method. It was found that thermal energy losses through the semitransparent...
Approximately forty percent of total building energy consumption is attributed to HVAC (heating, ventilation, and air conditioning) systems that aim to maintain healthy and comfortable indoor environments. An HVAC system is a network with several subsystems, and there exist heat transfer and balance among the zones of a building, as well as heat gains and losses through a building's envelope. Diverse...
DME (Dimethyl ether) synthesis from syngas with CO2 utilization through two-step and single step processes is analyzed thermodynamically. The influences of reaction temperature, H2/CO molar ratio, and CO2/CO molar ratio on CO and CO2 conversions, DME selectivity and yield, and thermal behavior are evaluated. Particular attention is paid to the comparison of the performance of DME synthesis between...
For the fixed total raw material cost and based on constructal theory and finite time thermodynamics, a BFIM (blast furnace iron-making) process is optimized by taking a complex function as optimization objective. The complex function is integrated with HM (hot metal) yield and useful energy of the BF (blast furnace). The optimal cost distribution of raw materials (namely “generalized optimal construct”)...
This study empirically investigates the relationship between energy consumption and economic growth for five Asia-Pacific countries over the 1965–2010 period by controlling other relevant economic variables. We use annual data and employ a bi-variate exponential GARCH in mean model (Nelson, 1991) [47] in which we incorporate economic uncertainty, real oil price and real exchange rate in addition to...
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