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José Corella - One of the best experts on this subject based on the ideXlab platform.
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A Review on Dual Fluidized-Bed Biomass Gasifiers
Industrial & Engineering Chemistry Research, 2007Co-Authors: José Corella, José M. Toledo, Gregorio MolinaAbstract:Biomass gasification with pure steam in a fluidized bed is a highly endothermal process that has been connected in several ways to a fluidized-bed combustor to burn the char that is generated in the gasifier. This resulted in what currently is called dual fluidized-bed (DFB) biomass Gasifiers. This review starts by describing the pioneering DFB biomass Gasifiers that were operated during the period of 1975−1990 by Kunii's group in Japan, Battelle−Columbus and FERCO in the United States, TNEE in France, AVSA in Belgium, etc., ... and Corella and Herguido's gasifier, which was operated during the period of 1989−1991. A description of the Gasifiers operated today in Europe (TU Wien and Gussing in Austria and ECN in The Netherlands), Japan (IHI Co., EBARA, AIST-Tsukuba), and the People's Republic of China (Dalian, Hangzhou, and Beijing) then is given. Their most-relevant operation data, and the results from these Gasifiers (mainly, the gaseous hydrogen (H2) and tar contents in the raw produced gas), are final...
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calculation of the conditions to get less than 2 g tar mn3 in a fluidized bed biomass gasifier
Fuel Processing Technology, 2006Co-Authors: José Corella, José M. Toledo, Gregorio MolinaAbstract:Abstract The experimental conditions under which a fluidized bed biomass gasifier can generate a gas with a tar content below 2 g/m n 3 are analyzed by using and developing the model recently published for those Gasifiers by Corella and Sanz [Fuel Process. Techn. 2005, 86, 1021–1053]. The analyzed experimental conditions were: the equivalence ratio, the partitioning of the air, between the primary and secondary flows, the location (height) of the inlet of the secondary air flow, the biomass moisture and the biomass flow rate. Results from the modelling work are presented for a given CFB biomass gasifier of commercial size. Some of these results are also being checked in a CFB biomass gasifier at small pilot plant scale. To obtain a gasification gas with a very low tar content the two most important experimental conditions are a high value for the equivalence ratio and a good in-gasifier material which determines the values of the kinetic constants of the reactions involved in the network at the gasifier.
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modeling circulating fluidized bed biomass Gasifiers results from a pseudo rigorous 1 dimensional model for stationary state
Fuel Processing Technology, 2006Co-Authors: Alvaro Sanz, José CorellaAbstract:Results from a 1-dimensional and semirigorous model for atmospheric and circulating fluidized bed biomass Gasifiers (CFBBGs), presented in the (previous) paper by Corella and Sanz [J. Corella, A. Sanz, Modeling circulating fluidized bed biomass Gasifiers. A pseudo-rigorous model for stationary state. Fuel Process. Technol. 86 (2005) 1021–1053], are shown here. Process variables predicted by the model are gas composition (H2, CO, CO2, CH4, C2Hn, H2O and O2 contents), gas yield, tar content in the flue gas and char concentration in the solids. Both axial profiles in the riser and values at the gasifier exit are calculated from the model and are shown here for some selected sets of process variables. Variables analyzed in depth are: total air flow (used as equivalence ratio, ER), percentage of secondary air flow, height (location) of the secondary air flow, biomass moisture and biomass flow rate, expressed as the biomass weight hourly space velocity in the gasifier. All the results from the model agree both with known published data and with some tests made to check the model.
Ahmed F Ghoniem - One of the best experts on this subject based on the ideXlab platform.
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reduced order modeling of the shell prenflo entrained flow gasifier
Fuel, 2013Co-Authors: Matteo Gazzani, Giampaolo Manzolini, Ennio Macchi, Ahmed F GhoniemAbstract:Abstract Pre-combustion capture applied to an integrated gasification combined cycle is a promising solution for greenhouse gas emission’s mitigation. For optimal design and operation of this cycle, detailed simulation of entrained flow Gasifiers and their integration in the flowsheet analysis is required. This paper describes the development of a reduced order model (ROM) for the Shell–Prenflo gasifier family, used for chemicals and power production because of its high efficiency and compatibility with a wide range of coal quality. Different from CFD analysis, ROM is computationally very efficient, taking around 1 min in a typical desktop or laptop computer, hence enabling the integration of the gasifier model and the overall power plant flowsheet simulation. Because of the gasifier complexity, which includes several gas recirculation loops and a membrane wall, particular attention is paid to: (i) the two-phase heat exchange process in the gasifier wall; and, (ii) the syngas quench process. Computed temperature, composition, velocity and reaction rate profiles inside the gasifier show good agreement with available data. The calculated cold gas efficiency is 82.5%, close to the given value of 82.8%. Results and several sensitivity analyses describe the implementation of the model to explore the potential for operating Gasifiers beyond the design point.
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a dynamic reduced order model for simulating entrained flow Gasifiers part ii model validation and sensitivity analysis
Fuel, 2012Co-Authors: Rory F D Monaghan, Ahmed F GhoniemAbstract:Abstract Part I of this series describes a dynamic reduced order model (ROM) that has been developed in Aspen Custom Modeler (ACM) for a range of entrained flow Gasifiers (EFGs) [1] . The ROM incorporates submodels for multiple feedstocks, mixing and recirculation, particle properties, drying and devolatilization, chemical kinetics, fluid dynamics, heat transfer, pollutant formation, slag behavior and syngas cooling. This paper describes ROM validation for steady-state simulation of four entrained flow Gasifiers for which experimental data is available, and sensitivity analysis for the GE gasifier design. The throughputs of these Gasifiers range from 0.1 to 1000 metric tonnes per day (tpd) (3 kW th –240 MW th ). Gasifier designs vary widely and simulations encompass the following configurations: dry and slurry feed, oxygen and air blowing, up and down flow, one and two stages, membrane and refractory lining, and quench and radiant cooling. Available experimental data consists of axial profiles for temperature, gas composition and carbon conversion, as well as exit values for temperature, composition, carbon conversion, char flow rate, syngas heating value and cold gas efficiency. Results show satisfactory ROM accuracy for all four gasifier designs simulated, which increases with knowledge of design, operating conditions and experimental data. In cases, where more detailed models that incorporate computational fluid dynamics (CFD) have been used for gasifier simulation, the ROM exhibits comparable accuracy. In sensitivity analysis, important input parameters are identified and varied 10% around their base case (validation) values. The resulting changes in ROM-predicted gasifier performance revealed that the most important parameters are those that determine reactor network model (RNM) geometry (reactor sizes and mass flow rates), particle physical (porosity, surface area, density, etc.) and kinetic properties, and slagging. In addition, the ROM takes about 1 min to run on a desktop PC, while CFD-based models can take multiple days on multiple processors.
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Simulation of a Commercial-Scale Entrained Flow Gasifier Using a Dynamic Reduced Order Model
Energy & Fuels, 2012Co-Authors: Rory F D Monaghan, Ahmed F GhoniemAbstract:The development of accurate, flexible, and robust dynamic reduced order models (ROMs) of entrained flow Gasifiers (EFGs) is an important step toward greater commercialization of that technology. Previous work by the authors described the development, validation, and sensitivity analysis of such a ROM.(1, 2) This paper presents the results of dynamic simulation of a commercial-scale General Electric (GE or Texaco) gasifier and syngas cooling system. The base case for simulation is introduced, and the ROM is used to simulate six cases of dynamic gasifier operation. The objective of this work is to develop a computationally efficient simulator to assess steady-state and dynamic performance of entrained flow Gasifiers under a wide range of realistic operating conditions. The six cases simulated are (1) removal of fluxant, (2) load following, (3) feed switching, (4) coal–petroleum coke cofiring, (5) coal–biomass cofiring, and (6) gasifier cold start. The results of dynamic simulation show that slagging propert...
Gregorio Molina - One of the best experts on this subject based on the ideXlab platform.
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A Review on Dual Fluidized-Bed Biomass Gasifiers
Industrial & Engineering Chemistry Research, 2007Co-Authors: José Corella, José M. Toledo, Gregorio MolinaAbstract:Biomass gasification with pure steam in a fluidized bed is a highly endothermal process that has been connected in several ways to a fluidized-bed combustor to burn the char that is generated in the gasifier. This resulted in what currently is called dual fluidized-bed (DFB) biomass Gasifiers. This review starts by describing the pioneering DFB biomass Gasifiers that were operated during the period of 1975−1990 by Kunii's group in Japan, Battelle−Columbus and FERCO in the United States, TNEE in France, AVSA in Belgium, etc., ... and Corella and Herguido's gasifier, which was operated during the period of 1989−1991. A description of the Gasifiers operated today in Europe (TU Wien and Gussing in Austria and ECN in The Netherlands), Japan (IHI Co., EBARA, AIST-Tsukuba), and the People's Republic of China (Dalian, Hangzhou, and Beijing) then is given. Their most-relevant operation data, and the results from these Gasifiers (mainly, the gaseous hydrogen (H2) and tar contents in the raw produced gas), are final...
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calculation of the conditions to get less than 2 g tar mn3 in a fluidized bed biomass gasifier
Fuel Processing Technology, 2006Co-Authors: José Corella, José M. Toledo, Gregorio MolinaAbstract:Abstract The experimental conditions under which a fluidized bed biomass gasifier can generate a gas with a tar content below 2 g/m n 3 are analyzed by using and developing the model recently published for those Gasifiers by Corella and Sanz [Fuel Process. Techn. 2005, 86, 1021–1053]. The analyzed experimental conditions were: the equivalence ratio, the partitioning of the air, between the primary and secondary flows, the location (height) of the inlet of the secondary air flow, the biomass moisture and the biomass flow rate. Results from the modelling work are presented for a given CFB biomass gasifier of commercial size. Some of these results are also being checked in a CFB biomass gasifier at small pilot plant scale. To obtain a gasification gas with a very low tar content the two most important experimental conditions are a high value for the equivalence ratio and a good in-gasifier material which determines the values of the kinetic constants of the reactions involved in the network at the gasifier.
K D P Nigam - One of the best experts on this subject based on the ideXlab platform.
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clean syngas from small commercial biomass Gasifiers a review of gasifier development recent advances and performance evaluation
International Journal of Hydrogen Energy, 2020Co-Authors: Richard Thomson, Philip Kwong, Ejaz Ahmad, K D P NigamAbstract:Abstract Biomass gasification is a key opportunity to produce bio-renewable energy, replacing conventional fossil fuels. Nevertheless, its commercial development for hydrogen and syngas production has been hampered by a range of intractable issues. This review examines reported issues, comparing their impacts on the commerciality of large-scale and small-scale biomass gasification. The development of Gasifiers is explored, and key indicators of performance discussed. A framework is developed to identify preferred selections of commercial gasifier technologies, using the key indicators to rank performance. Current commercial small-scale (70 kWe–3 MWe) gasifier technologies are reviewed confirming the dominance of derivatives of downdraft fixed bed Gasifiers. The importance of this study is to highlight the success of commercial small-scale gasification systems, utilising their specific economic advantages over larger scale projects, and to encourage their further deployment while a framework is provided to rank gasifier designs to facilitate targeting of research and development efforts for maximum effectiveness.
Stephen E. Zitney - One of the best experts on this subject based on the ideXlab platform.
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mathematical modeling of a single stage downward firing entrained flow gasifier
Industrial & Engineering Chemistry Research, 2012Co-Authors: Job S Kasule, Richard Turton, Debangsu Bhattacharyya, Stephen E. ZitneyAbstract:Gasifiers are the centerpieces of coal-fired integrated gasification combined cycle (IGCC) plants. Mathematical models of Gasifiers have been developed in recent literature to describe the physical and chemical processes taking place inside the reactor vessels. These models range from simple one-dimensional (1D) steady-state equilibrium models to higher-order, sophisticated, dynamic 2D and 3D computational fluid dynamics (CFD) models that describe coupled gas–solid hydrodynamics, heat and mass transfer, and reaction kinetics over the complex gasifier geometry. In the current work, a 1D steady-state model of a single-stage, downward-firing, oxygen-blown, slurry-fed, entrained-flow gasifier has been developed for use in the context of IGCC process simulation. In this mathematical model, mass, momentum, and energy balance equations for solid and gas phases are considered. The model includes a number of heterogeneous and homogeneous chemical reactions along with devolatilization and drying of the slurry feed....
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cfd modeling of entrained flow coal Gasifiers with improved physical and chemical sub models
2012Co-Authors: Stephen E. ZitneyAbstract:Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. While the turbulent multiphase reacting flow inside entrained-flow Gasifiers has been modeled through computational fluid dynamic (CFD), the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented here include a moisture vaporization model with consideration of high mass transfer rate, a coal devolatilization model with more species to represent coal volatiles and heating rate effect on volatile yield, and careful selection of global gas phase reaction kinetics. The enhanced CFD model is applied to simulate two typical oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both Gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngasmore » compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for systemwide design and optimization.« less
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cfd modeling of commercial scale entrained flow coal Gasifiers
2012Co-Authors: Stephen E. ZitneyAbstract:Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. Computational fluid dynamics (CFD) has been used to model the turbulent multiphase reacting flow inside commercial-scale entrained-flow coal Gasifiers. Due to the complexity of the physical and chemical processes involved, the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented in this paper include a moisture vaporization model with consideration of high mass transfer rate and a coal devolatilization model with more species to represent coal volatiles and the heating rate effect on volatile yield. The global gas phase reaction kinetics is also carefully selected. To predict a reasonable peak temperature of the coal/O{sub 2} flame inside an entrained-flow gasifier, the reserve reaction of H{sub 2} oxidation is included in the gas phase reaction model. The enhanced CFD model is applied to simulate two typical commercial-scale oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions insidemore » the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both Gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for system-wide design and optimization.« less