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- Balance equations (3)
- Nonequilibrium thermodynamics (3)
- Thermodynamic analysis (3)
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- Column grand composite curves (2)
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- Exergy loss (2)
- Reaction-transport systems (2)
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- And biological systems (1)
- Biodiesel (1)
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- Chemical reaction; Heat and mass transfer; Thermodynamic coupling; Non-equilibrium thermodynamics (1)
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- Distillation; Thermodynamic analysis; Pinch analysis;Exergy analysis: Equipartition principle; Thermoeconomics. (1)
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- External resistances (1)
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- Glycerol carbonate (1)
- Heat of transport (1)
- Heterogeneous catalyst (1)
- Information theory; biological systems; fluctuation theorem; thermodynamic coupling (1)
- Linear nonequilibrium thermodynamics (1)
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Articles 1 - 20 of 20
Full-Text Articles in Engineering
A Novel Biodiesel And Glycerol Carbonate Production Plant, Nghi Nguyen, Yasar Demirel
A Novel Biodiesel And Glycerol Carbonate Production Plant, Nghi Nguyen, Yasar Demirel
YASAR DEMIREL
Crude glycerol is the byproduct of biodiesel production plant and the economic value of glycerol may affect the profitability of the biodiesel production plant. As the production rate of bioglycerol increases, its market values drop considerably. Therefore, conversion of bioglycerol into value-added products can reduce the overall cost, hence, leading to a more economical biodiesel production plant. In a direct carboxylation reaction, CO2 reacts with glycerol to produce glycerol carbonate and water. This study presents a direct comparison of the economic analysis of the conventional biodiesel production plant and the possible next generation biodiesel-glycerol carbonate production plant. At the …
Thermodynamically Coupled Heat And Mass Flows In A Reaction-Transport System With External Resistances, Yasar Demirel
Thermodynamically Coupled Heat And Mass Flows In A Reaction-Transport System With External Resistances, Yasar Demirel
YASAR DEMIREL
Considerable work has been published on mathematically coupled nonlinear differential equations by neglecting thermodynamic coupling between heat and mass flows in reaction-transport systems. The thermodynamic coupling refers that a flow occurs without or against its primary thermodynamic driving force, which may be a gradient of temperature, or chemical potential, or reaction affinity. This study presents the modeling of thermodynamically coupled heat and mass flows of two components in a reaction-transport system with external heat and mass transfer resistances. The modeling equations are based on the linear nonequilibrium thermodynamics approach by assuming that the system is in the vicinity of global …
Using Thermally Coupled Reactive Distillation Columns In Biodiesel Production, Nghi Nguyen, Yaşar Demirel
Using Thermally Coupled Reactive Distillation Columns In Biodiesel Production, Nghi Nguyen, Yaşar Demirel
YASAR DEMIREL
Production of ethyl dodecanoate (biodiesel) using lauric acid and methanol with a solid acid catalyst of sulfated zirconia is studied by using two distillation sequences. In the first sequence, the methanol recovery column follows the reactive distillation column. In the second sequence, the reactive distillation and methanol recovery columns are thermally coupled. Thermally coupled distillation sequences may consume less energy by allowing interconnecting vapor and liquid streams between the two columns to elminate reboiler or condenser or both. Here we study the thermally coupled side-stripper reactive distillation and eliminate the condenser of the reactive distillation column. Both the sequences are …
Teaching Coupled Transport And Rate Processes, Yasar Demirel
Teaching Coupled Transport And Rate Processes, Yasar Demirel
YASAR DEMIREL
oupling refers to a flux occurring without its primary thermodynamic driving force; for example, mass flux without a concentration gradient called the thermal diffusion is a well-known coupled process. Coupling also refers to a flux occurring in a direction opposite to the direction imposed by its driving force; for example, a mass flux can occur from a low to a high concentration region and is called the active transport or uphill transport, such as potassium and sodium pumps coupled to chemical energy released by the hydrolysis of adenosine triphosphate (ATP) in biological systems. Although the coupled processes seem to be …
Thermodynamically Coupled Transport In Simple Catalytic Reactions, Yasar Demirel
Thermodynamically Coupled Transport In Simple Catalytic Reactions, Yasar Demirel
YASAR DEMIREL
Considerable work published on chemical reaction-diffusion systems investigates mainly mathematically coupled nonlinear differential equations. This study presents the modeling of a simple elementary chemical reaction with thermodynamically and mathematically coupled heat and mass transport with external mass and heat transfer resistances. The thermodynamic coupling refers that a flow occurs without or against its primary thermodynamic driving force, which may be a gradient of temperature or chemical potential. The modeling is based on the linear nonequilibrium thermodynamics approach and phenomenological equations by assuming that the system is in the vicinity of global equilibrium. This approach does not need detailed coupling mechanisms. …
Modeling Of Thermodynamically Coupled Reaction-Transport Systems, Yasar Demirel
Modeling Of Thermodynamically Coupled Reaction-Transport Systems, Yasar Demirel
YASAR DEMIREL
Nonisothermal reaction-diffusion systems control the behavior of many transport and rate processes in physical, chemical and biological systems, such as pattern formation and chemical pumps. Considerable work has been published on mathematically coupled nonlinear differential equations by neglecting thermodynamic coupling between a chemical reaction and transport processes of mass and heat. This study presents the modeling of thermodynamically coupled system of a simple elementary chemical reaction with molecular heat and mass transport. The thermodynamic coupling refers that a flow occurs without or against its primary thermodynamic driving force, which may be a gradient of temperature or chemical potential or reaction …
Linear-Nonequilibrium Thermodynamics Theory For Coupled Heat And Mass Transport, Yasar Demirel, Stanley I. Sandler
Linear-Nonequilibrium Thermodynamics Theory For Coupled Heat And Mass Transport, Yasar Demirel, Stanley I. Sandler
YASAR DEMIREL
Linear-nonequilibrium thermodynamics (LNET) has been used to express the entropy generation and dissipation functions representing the true forces and flows for heat and mass transport in a multicomponent fluid. These forces and flows are introduced into the phenomenological equations to formulate the coupling phenomenon between heat and mass flows. The degree of the coupling is also discussed. In the literature such coupling has been formulated incompletely and sometimes in a confusing manner. The reason for this is the lack of a proper combination of LNET theory with the phenomenological theory. The LNET theory involves identifying the conjugated flows and forces …
Nonequilibrium Thermodynamics Modeling Of Coupled Biochemical Cycles In Living Cells, Yaşar Demirel
Nonequilibrium Thermodynamics Modeling Of Coupled Biochemical Cycles In Living Cells, Yaşar Demirel
YASAR DEMIREL
Living cells represent open, nonequilibrium, self organizing, and dissipative systems maintained with the continuous supply of outside and inside material, energy, and information flows. The energy in the form of adenosine triphosphate is utilized in biochemical cycles, transport processes, protein synthesis, reproduction, and performing other biological work. The processes in molecular and cellular biological systems are stochastic in nature with varying spatial and time scales, and bounded with conservation laws, kinetic laws, and thermodynamic constraints, which should be taken into account by any approach for modeling biological systems. In component biology, this review focuses on the modeling of enzyme kinetics …
Nonequilibrium Thermodynamics In Engineering And Science, Y. Demirel
Nonequilibrium Thermodynamics In Engineering And Science, Y. Demirel
YASAR DEMIREL
The field of nonequilibrium thermodynamics has been a popular one outside the United States, especially in Europe, and scientists there from various disciplines have published extensively on the use of nonequilibrium thermodynamics in a large variety of biological, chemical, and mechanical engineering applications. In contrast, the number of publications from North America has been relatively modest. Here, we review the field of nonequilibrium thermodynamics to assess its utility and impact in engineering and science. We find that developments in the fields thermodynamic optimality of processes, dissipative structures, coupled transport and rate processes, and biological systems suggest that in some circumstances …
Excess Heat Capacity Surfaces For Water-Alkanol Mixtures By The Uniquac Model, Dr Y. Demirel
Excess Heat Capacity Surfaces For Water-Alkanol Mixtures By The Uniquac Model, Dr Y. Demirel
YASAR DEMIREL
Hydroorganic mixtures are industrial solvents that can serve as media to solubilize either water in hydrocarbon or a hydrophobic substance in water. In many cases the solubilizing capability is obtained via a homogeneous complex aqueous mixtures containing an alcohol. Since excess heat capacity CPE, is very sensitive to structural changes in mixtures, concentration and temperature dependence of CPE have been calculated by using the UNIQUAC model for the mixtures methanol(l)-water(%, ethanol(l)-water(2), and l-propanol(l)-water(2). The temperature-dependent parameters of the model estimated directly from CPE data at more than one different isotherm are used in the calculations. The overall deviations between the …
Retrofit Of Distillation Columns In Biodiesel Production Plants, Nghi Nguyen, Yaşar Demirel
Retrofit Of Distillation Columns In Biodiesel Production Plants, Nghi Nguyen, Yaşar Demirel
YASAR DEMIREL
Column grand composite curves and the exergy loss profiles produced by the Column-Targeting Tool of the Aspen Plus simulator are used to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a biodiesel production plant. Effectiveness of the retrofits is assessed by means of thermodynamics and economic improvements. We have considered a biodiesel plant utilizing three distillation columns to purify biodiesel (fatty acid methyl ester) and byproduct glycerol as well as reduce the waste. The assessments of the base case simulation have indicated the need for modifications for the distillation columns. …
Phase Stability Analysis Using Interval Newton Method With Nrtl Model, Hatice Gecegormez, Y. Demirel
Phase Stability Analysis Using Interval Newton Method With Nrtl Model, Hatice Gecegormez, Y. Demirel
YASAR DEMIREL
The Gibbs energy minimization using activity coefficient models and nonlinear equation solution techniques are commonly applied for phase stability problems. However, dependence on the initial estimates and multiple solutions for these highly nonlinear equations are common drawbacks for some of the conventional approaches. We have used interval Newton method with the local composition model of NRTL for the phase stability analysis of 10 binary systems and 2 ternary systems at various feed compositions to locate all the stationary points. Results indicate that the interval Newton method is reliable and efficient.
Retrofit Of Distillation Columns Using Thermodynamic Analysis, Y. Demirel
Retrofit Of Distillation Columns Using Thermodynamic Analysis, Y. Demirel
YASAR DEMIREL
Thermodynamic analysis provides the column grand composite curves and exergy loss profiles, which are becoming readily available for a converged distillation column simulation. For example, the Aspen Plus simulator performs the thermodynamic analysis through its Column–Targeting tool for rigorous column calculations. This study uses the column grand composite curves and the exergy loss profiles obtained from Aspen Plus to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a methanol plant. Effectiveness of the retrofits is also assessed by means of thermodynamics and economics. The methanol plant utilizes two distillation columns …
Thermodynamic Analysis Of Separation Systems, Y. Demirel
Thermodynamic Analysis Of Separation Systems, Y. Demirel
YASAR DEMIREL
Separation systems mainly involve interfacial mass and heat transfer as well as mixing. Distillation is a major separation system by means of heat supplied from a higher temperature level at the reboiler and rejected in the condenser at a lower temperature level. Therefore, it resembles a heat engine producing a separation work with a rather low efficiency. Lost work (energy) in separation systems is due to irreversible processes of heat, mass transfer, and mixing, and is directly related to entropy production according to the Gouy-Stodola principle. In many separation systems of absorption, desorption, extraction, and membrane separation, the major irreversibility …
Heat Transfer In Rarefied Gas At A Gas-Solid Interface, Y. Demirel
Heat Transfer In Rarefied Gas At A Gas-Solid Interface, Y. Demirel
YASAR DEMIREL
Modified expressions for the heat-transfer fluxes at the interface of a solid surface and a gas are given for different Knudsen-number regimes. These expressions for diatomic gases contain both a gas-reflection and a thermal accommodation coefficient. Parallel-plate, coaxial-cylindrical and concentric spherical surfaces are considered. A general expression for the thermal accommodation coefficient is based on experimental data. Sample numerical calculations of heat flux in different heat-transfer regimes are presented in terms of the reciprocal Knudsen number.
Non-Isothermal Reaction-Diffusion Systems With Thermodynamically Coupled Heat And Mass Transfer, Y. Demirel
Non-Isothermal Reaction-Diffusion Systems With Thermodynamically Coupled Heat And Mass Transfer, Y. Demirel
YASAR DEMIREL
Non-isothermal reaction-diffusion (RD) systems control the behavior of many transport and rate processes in physical, chemical, and biological systems. A considerable work has been published on mathematically coupled nonlinear differential equations of RD systems by neglecting the possible thermodynamic couplings among heat and mass fluxes, and reaction velocities. Here, the thermodynamic coupling refers that a flux occurs without its primary thermodynamic driving force, which may be gradient of temperature, or chemical potential, or reaction affinity. This study presents the modeling equations of non-isothermal RD systems with coupled heat and mass fluxes excluding the coupling of chemical reactions using the linear …
Nonequilibrium Thermodynamics, 3e Transport And Rate Processes In Physical, Chemical And Biological Systems, Yasar Demirel
Nonequilibrium Thermodynamics, 3e Transport And Rate Processes In Physical, Chemical And Biological Systems, Yasar Demirel
YASAR DEMIREL
Natural phenomena consist of simultaneously occurring transport processes and chemical reactions. These processes may interact with each other and may lead to self-organized structures, fluctuations, instabilities, and evolutionary systems. Nonequilibrium Thermodynamics, 3rd edition emphasizes the unifying role of thermodynamics in analyzing the natural phenomena. This third edition updates and expands on the first and second editions by focusing on the general balance equations for coupled processes of physical, chemical, and biological systems. The new edition contains a new chapter on stochastic approaches to include the statistical thermodynamics, mesoscopic nonequilibrium thermodynamics, fluctuation theory, information theory, and modeling the coupled biochemical systems …
Information In Biological Systems And The Fluctuation Theorem, Yasar Demirel
Information In Biological Systems And The Fluctuation Theorem, Yasar Demirel
YASAR DEMIREL
Some critical trends in information theory, its role in living systems and utilization in fluctuation theory are discussed. The mutual information of thermodynamic coupling is incorporated into the generalized fluctuation theorem by using information theory and nonequilibrium thermodynamics. Thermodynamically coupled dissipative structures in living systems are capable of degrading more energy, and processing complex information through developmental and environmental constraints. The generalized fluctuation theorem can quantify the hysteresis observed in the amount of the irreversible work in nonequilibrium regimes in the presence of information and thermodynamic coupling.
On The Measurement Of Entropy Production In Living Cells Under An Alternating Electric Field, Yasar Demirel
On The Measurement Of Entropy Production In Living Cells Under An Alternating Electric Field, Yasar Demirel
YASAR DEMIREL
This commentary is on the concept used by Ding and Luo (2013) to measure the rate of entropy production in normal cell and cancerous cell lines under an alternating electric field.
Influence Of Subenvironmental Conditions And Thermodynamic Coupling On A Simple Reaction-Transport Process In Biochemical Systems, Yasar Demirel, R Tevetia
Influence Of Subenvironmental Conditions And Thermodynamic Coupling On A Simple Reaction-Transport Process In Biochemical Systems, Yasar Demirel, R Tevetia
YASAR DEMIREL
Living systems must continuously receive substrates from subenvironment, and the population metabolic rate model is affected on this flow of substrates to be metabolized, its relevant variables, and the rate at which operates. This study focuses on the influences of resistances and bulk phase factors with in the subenvironment and by thermodynamic coupling on reaction-transport processes representing a simple enzymatic conversion of a substrate to a product. Thermodynamic coupling refers to mass flow, or a reaction velocity that occurs without or opposite to the direction imposed by its primary thermodynamic driving force. We considered the effects of (i) subenvironment resistances …