The Experts below are selected from a list of 474 Experts worldwide ranked by ideXlab platform
S. Zitney - One of the best experts on this subject based on the ideXlab platform.
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Development of a Dynamic Model and Control System for Load-Following Studies of Supercritical Pulverized Coal Power Plants
Processes, 2018Co-Authors: Parikshit Sarda, D. Bhattacharyya, S. Zitney, Elijah Hedrick, Katherine Reynolds, Benjamin OmellAbstract:Traditional energy production plants are increasingly forced to cycle their load and operate under low-load conditions in response to growth in intermittent renewable generation. A plant-wide dynamic model of a supercritical pulverized coal (SCPC) power plant has been developed in the Aspen Plus Dynamics® (APD) software environment and the impact of advanced control strategies on the transient responses of the key variables to load-following operation and disturbances can be studied. Models of various key unit operations, such as the steam turbine, are developed in Aspen Custom Modeler® (ACM) and integrated in the APD environment. A coordinated control system (CCS) is developed above the regulatory control layer. Three control configurations are evaluated for the control of the main steam; the reheat steam temperature is also controlled. For studying servo control performance of the CCS, the load is decreased from 100% to 40% at a ramp rate of 3% load per min. The impact of a disturbance due to a change in the coal feed composition is also studied. The CCS is found to yield satisfactory performance for both servo control and disturbance rejection.
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One-Dimensional Dynamic Modeling of a Single-Stage Downward-Firing Entrained-Flow Coal Gasifier
Energy & Fuels, 2014Co-Authors: J. Kasule, R. Turton, D. Bhattacharyya, S. ZitneyAbstract:In the current paper, a one-dimensional partial differential equation (PDE)-based dynamic model and its simulation results are presented for a single-stage down-fired entrained-flow gasifier. The gasifier model comprises mass, momentum, and energy balances for the gas and solid phases. The initial gasification processes of water evaporation and coal devolatilization and the key heterogeneous and homogeneous chemical reactions have also been modeled. The resulting coupled system of PDEs and algebraic equations is solved using the well-known method of lines in Aspen Custom Modeler. In addition to the dynamic gasifier model, efficient control strategies that can satisfactorily perform both servo and disturbance rejection functions have been developed for the entrained-flow gasifier. The dynamic variations of key gasifier output variables in response to the disturbances commonly encountered in industrial operation are presented. Output variables of interest include gas and solid phase temperatures, synthesis ...
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dynamic modeling and control studies of a two stage bubbling fluidized bed adsorber reactor for solid sorbent co2 capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Srinivasarao Modekurti, D. Bhattacharyya, S. ZitneyAbstract:A one-dimensional, nonisothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid–sorbent carbon dioxide (CO2) capture using Aspen Custom Modeler (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributors have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO2 capture rate and flue gas outlet temperatures have been studied by simulating typical disturbanc...
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Dynamic Modeling and Control Studies of a Two-Stage Bubbling Fluidized Bed Adsorber-Reactor for Solid–Sorbent CO2 Capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Srinivasarao Modekurti, D. Bhattacharyya, S. ZitneyAbstract:A one-dimensional, nonisothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid–sorbent carbon dioxide (CO2) capture using Aspen Custom Modeler (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributors have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO2 capture rate and flue gas outlet temperatures have been studied by simulating typical disturbanc...
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On the modeling of a single-stage, entrained-flow gasifier using Aspen Custom Modeler (ACM)
2010Co-Authors: J. Kasule, R. Turton, D. Bhattacharyya, S. ZitneyAbstract:Coal-fired gasifiers are the centerpiece of integrated gasification combined cycle (IGCC) power plants. The gasifier produces synthesis gas that is subsequently converted into electricity through combustion in a gas turbine. Several mathematical models have been developed to study the physical and chemical processes taking place inside the gasifier. Such models range from simple one-dimensional (1D) steady-state models to sophisticated dynamic 3D computational fluid dynamics (CFD) models that incorporate turbulence effects in the reactor. The practical operation of the gasifier is dynamic in nature but most 1D and some higher-dimensional models are often steady state. On the other hand, many higher order CFD-based models are dynamic in nature, but are too computationally expensive to be used directly in operability and controllability dynamic studies. They are also difficult to incorporate in the framework of process simulation software such as Aspen Plus Dynamics. Thus lower-dimensional dynamic models are still useful in these types of studies. In the current study, a 1D dynamic model for a single-stage, downward-firing, entrained-flow GE-type gasifier is developed using Aspen Custom Modeler{reg_sign} (ACM), which is a commercial equation-based simulator for creating, editing, and re-using models of process units. The gasifier model is based on mass, momentum, and energy balancesmore » for the solid and gas phases. The physical and chemical reactions considered in the model are drying, devolatilization/pyrolysis, gasification, combustion, and the homogeneous gas phase reactions. The dynamic gasifier model is being developed for use in a plant-wide dynamic model of an IGCC power plant. For dynamic simulation, the resulting highly nonlinear system of partial differential algebraic equations (PDAE) is solved in ACM using the well-known Method of Lines (MoL) approach. The MoL discretizes the space domain and leaves the time domain continuous, thereby converting the PDAE to a differential algebraic equation (DAE) system with respect to time. The DAE system is solved using a variable-step implicit Euler integrator. For steady-state simulations, the set of nonlinear algebraic equations are solved using a Newton-type method. In this presentation, preliminary results from the steady-state non-isothermal gasifier model will be reported. Comparisons of the results from the gasifier model to available pilot plant data, industrial gasifier data, and other published models will be made. Sensitivity studies will be presented for different types of coal and operating conditions.« less
Srinivasarao Modekurti - One of the best experts on this subject based on the ideXlab platform.
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dynamic modeling and control studies of a two stage bubbling fluidized bed adsorber reactor for solid sorbent co2 capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Srinivasarao Modekurti, D. Bhattacharyya, S. ZitneyAbstract:A one-dimensional, nonisothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid–sorbent carbon dioxide (CO2) capture using Aspen Custom Modeler (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributors have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO2 capture rate and flue gas outlet temperatures have been studied by simulating typical disturbanc...
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Dynamic Modeling and Control Studies of a Two-Stage Bubbling Fluidized Bed Adsorber-Reactor for Solid–Sorbent CO2 Capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Srinivasarao Modekurti, D. Bhattacharyya, S. ZitneyAbstract:A one-dimensional, nonisothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid–sorbent carbon dioxide (CO2) capture using Aspen Custom Modeler (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributors have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO2 capture rate and flue gas outlet temperatures have been studied by simulating typical disturbanc...
D. Bhattacharyya - One of the best experts on this subject based on the ideXlab platform.
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Development of a Dynamic Model and Control System for Load-Following Studies of Supercritical Pulverized Coal Power Plants
Processes, 2018Co-Authors: Parikshit Sarda, D. Bhattacharyya, S. Zitney, Elijah Hedrick, Katherine Reynolds, Benjamin OmellAbstract:Traditional energy production plants are increasingly forced to cycle their load and operate under low-load conditions in response to growth in intermittent renewable generation. A plant-wide dynamic model of a supercritical pulverized coal (SCPC) power plant has been developed in the Aspen Plus Dynamics® (APD) software environment and the impact of advanced control strategies on the transient responses of the key variables to load-following operation and disturbances can be studied. Models of various key unit operations, such as the steam turbine, are developed in Aspen Custom Modeler® (ACM) and integrated in the APD environment. A coordinated control system (CCS) is developed above the regulatory control layer. Three control configurations are evaluated for the control of the main steam; the reheat steam temperature is also controlled. For studying servo control performance of the CCS, the load is decreased from 100% to 40% at a ramp rate of 3% load per min. The impact of a disturbance due to a change in the coal feed composition is also studied. The CCS is found to yield satisfactory performance for both servo control and disturbance rejection.
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One-Dimensional Dynamic Modeling of a Single-Stage Downward-Firing Entrained-Flow Coal Gasifier
Energy & Fuels, 2014Co-Authors: J. Kasule, R. Turton, D. Bhattacharyya, S. ZitneyAbstract:In the current paper, a one-dimensional partial differential equation (PDE)-based dynamic model and its simulation results are presented for a single-stage down-fired entrained-flow gasifier. The gasifier model comprises mass, momentum, and energy balances for the gas and solid phases. The initial gasification processes of water evaporation and coal devolatilization and the key heterogeneous and homogeneous chemical reactions have also been modeled. The resulting coupled system of PDEs and algebraic equations is solved using the well-known method of lines in Aspen Custom Modeler. In addition to the dynamic gasifier model, efficient control strategies that can satisfactorily perform both servo and disturbance rejection functions have been developed for the entrained-flow gasifier. The dynamic variations of key gasifier output variables in response to the disturbances commonly encountered in industrial operation are presented. Output variables of interest include gas and solid phase temperatures, synthesis ...
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dynamic modeling and control studies of a two stage bubbling fluidized bed adsorber reactor for solid sorbent co2 capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Srinivasarao Modekurti, D. Bhattacharyya, S. ZitneyAbstract:A one-dimensional, nonisothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid–sorbent carbon dioxide (CO2) capture using Aspen Custom Modeler (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributors have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO2 capture rate and flue gas outlet temperatures have been studied by simulating typical disturbanc...
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Dynamic Modeling and Control Studies of a Two-Stage Bubbling Fluidized Bed Adsorber-Reactor for Solid–Sorbent CO2 Capture
Industrial & Engineering Chemistry Research, 2013Co-Authors: Srinivasarao Modekurti, D. Bhattacharyya, S. ZitneyAbstract:A one-dimensional, nonisothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid–sorbent carbon dioxide (CO2) capture using Aspen Custom Modeler (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributors have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO2 capture rate and flue gas outlet temperatures have been studied by simulating typical disturbanc...
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On the modeling of a single-stage, entrained-flow gasifier using Aspen Custom Modeler (ACM)
2010Co-Authors: J. Kasule, R. Turton, D. Bhattacharyya, S. ZitneyAbstract:Coal-fired gasifiers are the centerpiece of integrated gasification combined cycle (IGCC) power plants. The gasifier produces synthesis gas that is subsequently converted into electricity through combustion in a gas turbine. Several mathematical models have been developed to study the physical and chemical processes taking place inside the gasifier. Such models range from simple one-dimensional (1D) steady-state models to sophisticated dynamic 3D computational fluid dynamics (CFD) models that incorporate turbulence effects in the reactor. The practical operation of the gasifier is dynamic in nature but most 1D and some higher-dimensional models are often steady state. On the other hand, many higher order CFD-based models are dynamic in nature, but are too computationally expensive to be used directly in operability and controllability dynamic studies. They are also difficult to incorporate in the framework of process simulation software such as Aspen Plus Dynamics. Thus lower-dimensional dynamic models are still useful in these types of studies. In the current study, a 1D dynamic model for a single-stage, downward-firing, entrained-flow GE-type gasifier is developed using Aspen Custom Modeler{reg_sign} (ACM), which is a commercial equation-based simulator for creating, editing, and re-using models of process units. The gasifier model is based on mass, momentum, and energy balancesmore » for the solid and gas phases. The physical and chemical reactions considered in the model are drying, devolatilization/pyrolysis, gasification, combustion, and the homogeneous gas phase reactions. The dynamic gasifier model is being developed for use in a plant-wide dynamic model of an IGCC power plant. For dynamic simulation, the resulting highly nonlinear system of partial differential algebraic equations (PDAE) is solved in ACM using the well-known Method of Lines (MoL) approach. The MoL discretizes the space domain and leaves the time domain continuous, thereby converting the PDAE to a differential algebraic equation (DAE) system with respect to time. The DAE system is solved using a variable-step implicit Euler integrator. For steady-state simulations, the set of nonlinear algebraic equations are solved using a Newton-type method. In this presentation, preliminary results from the steady-state non-isothermal gasifier model will be reported. Comparisons of the results from the gasifier model to available pilot plant data, industrial gasifier data, and other published models will be made. Sensitivity studies will be presented for different types of coal and operating conditions.« less
Chengliang Chang - One of the best experts on this subject based on the ideXlab platform.
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modeling and optimization of a solar driven membrane distillation desalination system
Renewable Energy, 2010Co-Authors: Hsua Chang, Gowbi Wang, Yihhang Che, Chengliang ChangAbstract:The desalination technology using membrane distillation driven by solar energy is a feasible solution for reducing the energy cost. A dynamic simulation model for a solar driven membrane distillation desalination system (SMDDS) is developed on the Aspen Custom Modeler® (ACM) platform for the system performance and optimization study. The rigorous model for the spiral-wound air gap membrane distillation (SP-AGMD) module takes into account the heat and mass transfer resistances associated with each composing layer. The effects of adopting different objective functions, solar radiation conditions, thermal storage tank configurations, as well as the flowrates of the membrane distillation module and the thermal storage tank on the optimized performance are reported. Simple thermal storage tank and lower flowrate of the membrane distillation module are advantageous to higher water production rate. A control system using conventional PI (Proportional/Integral) controllers is proposed and the water production rate can reach about 87% of the optimal result for clear sky operation.
Inmaculada Ortiz - One of the best experts on this subject based on the ideXlab platform.
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Optimal Production of Ethyl Tert-butyl Ether using Pervaporation-based Hybrid Processes through the Analysis of Process Flowsheet
Computer Aided Chemical Engineering, 2017Co-Authors: Daniel Gorri, Adham Norkobilov, Inmaculada OrtizAbstract:Abstract This work applied a process design methodology based on the combined use of process simulation and heat integration with pinch analysis to analyse a PV-integrated hybrid process for ETBE production. Mathematical modelling and simulation of the membrane module have been performed using Aspen Custom Modeler and linked with Aspen Plus software to describe the overall process. Simulation results showed that the hybrid process, in which the PV modules are located on a side-stream withdrawn from the distillation column, is more favourable in energy consumption and it shows lower content of ethanol in distillate stream than other membrane integrated hybrid processes. Heat integration with pinch analysis shows that it is possible to achieve savings of up to 18% in utilities consumption.
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Development and Validation of a Dynamic Model for Regeneration of Passivating Baths using Membrane Contactors
Computer Aided Chemical Engineering, 2010Co-Authors: Eugenio Bringas, Rosa Mediavilla, A.m. Urtiaga, Inmaculada OrtizAbstract:Abstract Selective liquid membranes have been traditionally employed for liquid/liquid and gas/liquid mass transfer in a wide range of applications. In particular, the Emulsion Pertraction Technology (EPT) using hollow fiber membrane contactors is a promising alternative to carry out the selective separation of metals from complex mixtures. However, the application of a new technology requires of reliable mathematical models and parameters that serve for design and optimization purposes allowing to accurate scale-up processes. This work reports the methodology for the development of a dynamic model to describe the kinetics of the EPT separation-concentration process applied to the regeneration of spent trivalent chromium-based passivating baths. The regeneration stage aims at the selective removal of Zn2+ dragged from previous steps in the plating line, not affecting the level of Cr3+ concentration in the passivating bath. In the case study the mathematical model was initially developed in a rigorous way and in a further analysis, a systematic method for its simplification was established. Then, the system of partial differential and algebraic equations obtained was integrated using the commercial software package Aspen Custom Modeler (from AspenTECH) making possible the analysis of the model sensibility under different values of the operation variables. Finally, the model was validated with kinetic data obtained at laboratory scale.
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selective membrane alternative to the recovery of zinc from hot dip galvanizing effluents
Journal of Membrane Science, 2009Co-Authors: J A Carrera, Eugenio Bringas, M San F Roman, Inmaculada OrtizAbstract:Abstract This work reports the study of the kinetics of zinc recovery from spent pickling solutions by means of emulsion pertraction technology (EPT) in order to reuse the metal in electrolytic processes. Tributyl phosphate (TBP) and service water were used as extraction (EX) and back-extraction (BEX) agents, respectively. Kinetic experiments were carried out in hollow fiber membrane contactors in order to analyse the influence of several operation variables on the rate of zinc recovery. A mathematical model that considers the mass transfer resistance shared between the organic liquid membrane and the organic phase boundary layer was developed; the mass transfer coefficients were estimated by means of the parameter estimation tool Aspen Custom Modeler (from AspenTECH) to obtain the values k m = 2.68 × 10 −7 m/s and A V k o = 0.0125 s −1 . Simulated results agreed satisfactorily well with experimental data. Consequently, the kinetic model and parameters were confirmed. Finally, a comparison between EPT and non-dispersive solvent extraction (NDSX) was carried out in order to evaluate the advantages and disadvantages of both membrane configurations.