The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Karlheinz Schaber - One of the best experts on this subject based on the ideXlab platform.
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formation of hydrobromic and hydrochloric acid aerosols in wet flue Gas Cleaning processes
Chemical Engineering Communications, 2013Co-Authors: S Sinanis, A Wix, Karlheinz SchaberAbstract:The formation and behavior of hydrobromic and hydrochloric acid aerosols in a wet flue Gas Cleaning pilot plant were investigated. The optical three-wavelength extinction (3-WE) method was used to determine mean aerosol droplet diameters and droplet number concentrations. The experimental data are compared with theoretical results of the simulation tool AerCoDe (aerosol formation in contact devices). Results are presented for a raw Gas temperature of 200°C and raw Gas concentrations up to 260 mg/m3(STP) for HBr, and 2500 mg/m3 (STP) for HCl. Under these conditions aerosol formation for both species is initiated by heterogeneous nucleation. It is shown that during absorption processes HBr is forming essentially higher supersaturated Gas phases in comparison to HCl, resulting in higher droplet number concentrations and smaller droplet sizes. For both species the number concentration is a strong function of the maximum degree of saturation, which corresponds to the classical theory of heterogeneous nucleatio...
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a simulation tool for aerosol formation during sulphuric acid absorption in a Gas Cleaning process
Journal of Aerosol Science, 2010Co-Authors: L Brachert, S Sinanis, Karlheinz SchaberAbstract:Abstract A simulation tool has been developed to predict sulphuric acid aerosol formation in typical industrial absorption processes for Gas Cleaning. The underlying model comprises homogeneous nucleation and the growth of a polydisperse droplet collective under the special circumstances of a Gas–liquid contact device where heat and mass transfer processes between the bulk phases take place simultaneously. The model is applied to a hot flue Gas (200 °C) with sulphuric acid concentrations between 5 and 100 mg m −3 (STP) (STP: standard temperature and pressure ) . The simulation yields high droplet number concentrations up to 10 16 m −3 especially for low Gas inlet concentrations of sulphuric acid (5 mg m −3 (STP)), and very small droplet sizes in the range 20–100 nm. The droplet number concentrations decrease and the droplet sizes increase with increasing sulphuric acid inlet concentrations. It is shown that small droplets (
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characterization of sulphuric acid and ammonium sulphate aerosols in wet flue Gas Cleaning processes
Chemical Engineering and Processing, 2008Co-Authors: S Sinanis, Karlheinz SchaberAbstract:Abstract Sulphuric acid aerosols can be formed in wet flue Gas Cleaning processes by spontaneous condensation initiated mainly by homogeneous nucleation. Even at low Gas inlet concentrations of SO 3 (2 mg/m 3 (STP)) aerosol formation can be observed. For the design of absorption processes and sulphuric acid mist precipitators the aerosol characteristic data like mean diameter and number concentration are required for different process conditions and raw Gas concentrations. In the present contribution, a combination of an experimental method with the simulation tool AerCode is described, which permits the determination of the diameter and the number concentration of sulphuric acid aerosols formed in wet flue Gas Cleaning processes. As a result of the extreme azeotropic phase behaviour of the H 2 SO 4 –H 2 O system the mechanism of homogeneous nucleation is predominant for aerosol formation in absorption processes. Furthermore, the influence of soluble and insoluble particles on homogeneous nucleation in the system H 2 SO 4 –H 2 O is shown. The investigation of the influence of insoluble foreign nuclei shows that at high SO 3 raw Gas concentrations >30 mg/m 3 (STP), the mechanism of homogeneous nucleation is predominant. At lower raw Gas concentrations between 2 and 10 mg/m 3 (STP) SO 3 heterogeneous nucleation is the major reason for aerosol formation. Solid (NH 4 ) 2 SO 4 particles that are formed by the reaction between H 2 SO 4 and NH 3 in the Gas phase are used as soluble foreign nuclei. The studies show that aerosol formation is determined by the reaction component whose concentration is below the stoichiometric ratio. It was observed that in the case of an excess of sulphuric acid a decrease of the amount of ammonia leads to an increase of the particle size combined with a decrease in the number concentration. If ammonia is in excess, the decrease in the concentration of ammonia changes neither the particle size nor the number concentration of the aerosol significantly.
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characterization of sulphuric acid and ammonium sulphate aerosols in wet flue Gas Cleaning processes
Chemical Engineering and Processing, 2008Co-Authors: S Sinanis, Karlheinz SchaberAbstract:Abstract Sulphuric acid aerosols can be formed in wet flue Gas Cleaning processes by spontaneous condensation initiated mainly by homogeneous nucleation. Even at low Gas inlet concentrations of SO 3 (2 mg/m 3 (STP)) aerosol formation can be observed. For the design of absorption processes and sulphuric acid mist precipitators the aerosol characteristic data like mean diameter and number concentration are required for different process conditions and raw Gas concentrations. In the present contribution, a combination of an experimental method with the simulation tool AerCode is described, which permits the determination of the diameter and the number concentration of sulphuric acid aerosols formed in wet flue Gas Cleaning processes. As a result of the extreme azeotropic phase behaviour of the H 2 SO 4 –H 2 O system the mechanism of homogeneous nucleation is predominant for aerosol formation in absorption processes. Furthermore, the influence of soluble and insoluble particles on homogeneous nucleation in the system H 2 SO 4 –H 2 O is shown. The investigation of the influence of insoluble foreign nuclei shows that at high SO 3 raw Gas concentrations >30 mg/m 3 (STP), the mechanism of homogeneous nucleation is predominant. At lower raw Gas concentrations between 2 and 10 mg/m 3 (STP) SO 3 heterogeneous nucleation is the major reason for aerosol formation. Solid (NH 4 ) 2 SO 4 particles that are formed by the reaction between H 2 SO 4 and NH 3 in the Gas phase are used as soluble foreign nuclei. The studies show that aerosol formation is determined by the reaction component whose concentration is below the stoichiometric ratio. It was observed that in the case of an excess of sulphuric acid a decrease of the amount of ammonia leads to an increase of the particle size combined with a decrease in the number concentration. If ammonia is in excess, the decrease in the concentration of ammonia changes neither the particle size nor the number concentration of the aerosol significantly.
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simulations and experiments on the formation of ammonium chloride particles in wet scrubbers
Chemical Engineering and Processing, 2003Co-Authors: S I Shabunya, B Wende, S P Fisenko, Karlheinz SchaberAbstract:Abstract The formation of aqueous ammonium chloride aerosols has been investigated both experimentally and by simulation. The considered process is a flue Gas Cleaning plant in which hot Gases containing Gaseous ammonia and hydrogen chloride at 200 °C enter a quench cooler in which they are brought in intense contact with water and chilled down. The processes of absorption, cooling and nucleation occur simultaneously. The simulations are based on a description of the process according to the film model combined with homogeneous nucleation theory. The experiments were done at a semi-technical flue Gas Cleaning plant. It is found that the proposed model is able to predict the qualitative behaviour of the system, especially its sensitivity to a change of the concentrations of the two pollutants at its entry. However, to get quantitative coincidence an adjustment is necessary. In this, the governing parameter is the surface tension of ammonium chloride.
P V Aravind - One of the best experts on this subject based on the ideXlab platform.
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evaluation of high temperature Gas Cleaning options for biomass Gasification product Gas for solid oxide fuel cells
Progress in Energy and Combustion Science, 2012Co-Authors: P V Aravind, Wiebren De JongAbstract:Abstract An analysis of high temperature Gas Cleaning systems for Cleaning the product Gas of biomass Gasification for fueling solid oxide fuel cells (SOFCs) is presented. Influence of biomass derived contaminants on SOFCs is briefly presented and the removal of potential contaminants such as tar, particulates, H 2 S and HCl, alkali compounds from biosynGas is reviewed. It appears that the Gasification product Gas can be cleaned to meet the requirements of SOFCs based on Ni/GDC anodes at high temperatures (typically in the range of 1023–1223 K) by using currently known Gas Cleaning methods. Although information from literature, results from chemical equilibrium studies and preliminary experiments were sufficient to put forward a conceptual design for a high temperature Gas Cleaning system, detailed experimental investigations are still required. This is needed to obtain detailed information on contaminant tolerance of SOFCs, and to arrive at detailed designs of Gas Cleaning units that are economically viable for biomass Gasifier-SOFC systems.
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alternative system designs of biomass Gasification sofc gt hybrid systems
International Journal of Hydrogen Energy, 2011Co-Authors: Richard Toonssen, P V Aravind, Stefano Sollai, N Woudstra, Adrian H M VerkooijenAbstract:Abstract In this paper, four different systems based on integrated hybrid solid oxide fuel cell Gas turbine and biomass Gasification are modelled to study the influence of the Gasification technology, Gas Cleaning technology and system scale on the overall system performance. The different Gasification technologies evaluated are the atmospheric indirect steam Gasification and pressurized direct air Gasification. The evaluated Gas Cleaning technologies are low temperature Gas Cleaning and high temperature Gas Cleaning and the two scales are 100 kW e and 30 MW e . The system performances have been analysed by means of models developed with the thermodynamic flow-sheeting program Cycle-Tempo. The system alternatives are compared using the results from the different models and the exergy analysis made for each system design. The results show that the large scale system based on pressurized direct air Gasification and high temperature Gas Cleaning has the highest electrical exergy efficiency of 49.9%. It was also found that the Gasification technology has hardly any influence on the overall system performance. High temperature Gas Cleaning results in a slightly higher performance (0.5%) compared to low temperature Gas Cleaning. Large scale systems have a higher efficiency than small scale systems, due to larger exergy losses in mainly balance of plant components.
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thermodynamic evaluation of small scale systems with biomass Gasifiers solid oxide fuel cells with ni gdc anodes and Gas turbines
Journal of Power Sources, 2009Co-Authors: P V Aravind, N Woudstra, T Woudstra, H SpliethoffAbstract:Abstract Thermodynamic calculations were carried out to evaluate the performance of small-scale Gasifier–SOFC–GT systems of the order of 100 kW. Solid Oxide Fuel Cells (SOFCs) with Nickel/Gadolinia Doped Ceria (Ni/GDC) anodes were considered. High system electrical efficiencies above 50% are achievable with these systems. The results obtained indicate that when Gas Cleaning is carried out at temperatures lower than Gasification temperature, additional steam may have to be added to biosynGas in order to avoid carbon deposition. To analyze the influence of Gas Cleaning at lower temperatures and steam addition on system efficiency, additional system calculations were carried out. It is observed that steam addition does not have significant impact on system electrical efficiency. However, generation of additional steam using heat from Gas turbine outlet decreases the thermal energy and exergy available at the system outlet thereby decreasing total system efficiency. With the Gas Cleaning at atmospheric temperature, there is a decrease in the electrical efficiency of the order of 4–5% when compared to the efficiency of the systems working with intermediate to high Gas-Cleaning temperatures.
H Spliethoff - One of the best experts on this subject based on the ideXlab platform.
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effect of internal hydrocarbon reforming during coupled operation of a biomass Gasifier with hot Gas Cleaning and sofc stacks
Energy Science & Engineering, 2019Co-Authors: F Fischer, Michael Hauser, Maximilian Hauck, Stephan Herrmann, S Fendt, Hyeondeok Jeong, Christian Lenser, Norbert H Menzler, H SpliethoffAbstract:In the context of energy transition and climate change, a combination of highly efficient modern solid oxide fuel cells (SOFC) and thermo-chemical conversion of biogenic residues could complement other intermittent renewable sources such as wind and solar. In order to reduce required Gas Cleaning efforts and to increase the process efficiency, the influence of hydrocarbons on SOFC performance is experimentally investigated in this study. For the first time, the operation of Ni/YSZ anode-supported cells in Julich F10 stacks is performed with pre-reformed and with bio-synGas containing full hydrocarbon content at realistic current densities. Sulfur and other impurities were removed in both cases. No degradation could be observed within normal operation on clean Gas. With the tar reformer bypassed, the pressure drop over the stack increased due to severe carbon deposition on the anode substrate and the nickel current collector mesh inside the SOFC stack, so that operation had to be terminated after five hours. This behavior is different from single-cell tests, where electrochemical degradation is the limiting factor. The results show that improvements are not only necessary for cell materials and that future research must also consider other stack components.
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thermodynamic evaluation of small scale systems with biomass Gasifiers solid oxide fuel cells with ni gdc anodes and Gas turbines
Journal of Power Sources, 2009Co-Authors: P V Aravind, N Woudstra, T Woudstra, H SpliethoffAbstract:Abstract Thermodynamic calculations were carried out to evaluate the performance of small-scale Gasifier–SOFC–GT systems of the order of 100 kW. Solid Oxide Fuel Cells (SOFCs) with Nickel/Gadolinia Doped Ceria (Ni/GDC) anodes were considered. High system electrical efficiencies above 50% are achievable with these systems. The results obtained indicate that when Gas Cleaning is carried out at temperatures lower than Gasification temperature, additional steam may have to be added to biosynGas in order to avoid carbon deposition. To analyze the influence of Gas Cleaning at lower temperatures and steam addition on system efficiency, additional system calculations were carried out. It is observed that steam addition does not have significant impact on system electrical efficiency. However, generation of additional steam using heat from Gas turbine outlet decreases the thermal energy and exergy available at the system outlet thereby decreasing total system efficiency. With the Gas Cleaning at atmospheric temperature, there is a decrease in the electrical efficiency of the order of 4–5% when compared to the efficiency of the systems working with intermediate to high Gas-Cleaning temperatures.
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analysis of potential Gasification alkali getters using a new high temperature pressurized simultaneous thermal analyzer p sta
International Conference on Coal Science & Technology (ICCS&T) 2009, 2009Co-Authors: F Hauk, S Gleis, H SpliethoffAbstract:Hot Gas Cleaning, especially hot alkali Gas Cleaning, in integrated Gasification combined cycle (IGCC) power plants is a key technology for a better performance of this desirable power plant technology. In this study potential mineral getters were tested for their total temperature dependent chemisorption capacity for alkali compounds under conditions relevant to IGCC power generation systems. For these laboratory tests a benchmark setting pressurized simultaneous thermal analysis (PSTA) device was developed. It allows working pressures ranging from vacuum to 0.6 MPa absolute pressure at a maximum working temperature of 1750 textdegreeC and thus conditions far beyond any known pressurized STA systems.The alkali retention potential of a series of three potential getter minerals mostly aluminosilicates) was identified at temperatures up to 1750 textdegreeC in reducing atmospheres. Although silicon-rich aluminosilicates show higher alkali release at temperatures above 1250 textdegreeC they seem to offer better retention potential at lower temperatures. The points of maximum release speed are shifted to about 150 textdegreeC higher temperatures with pressure increasing from ambient pressure to 0.5 MPa overpressure. Thermochemical calculations showed acceptable agreement with experiments. The release fraction of sodium can theoretically be reduced by around 40
S Sinanis - One of the best experts on this subject based on the ideXlab platform.
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formation of hydrobromic and hydrochloric acid aerosols in wet flue Gas Cleaning processes
Chemical Engineering Communications, 2013Co-Authors: S Sinanis, A Wix, Karlheinz SchaberAbstract:The formation and behavior of hydrobromic and hydrochloric acid aerosols in a wet flue Gas Cleaning pilot plant were investigated. The optical three-wavelength extinction (3-WE) method was used to determine mean aerosol droplet diameters and droplet number concentrations. The experimental data are compared with theoretical results of the simulation tool AerCoDe (aerosol formation in contact devices). Results are presented for a raw Gas temperature of 200°C and raw Gas concentrations up to 260 mg/m3(STP) for HBr, and 2500 mg/m3 (STP) for HCl. Under these conditions aerosol formation for both species is initiated by heterogeneous nucleation. It is shown that during absorption processes HBr is forming essentially higher supersaturated Gas phases in comparison to HCl, resulting in higher droplet number concentrations and smaller droplet sizes. For both species the number concentration is a strong function of the maximum degree of saturation, which corresponds to the classical theory of heterogeneous nucleatio...
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a simulation tool for aerosol formation during sulphuric acid absorption in a Gas Cleaning process
Journal of Aerosol Science, 2010Co-Authors: L Brachert, S Sinanis, Karlheinz SchaberAbstract:Abstract A simulation tool has been developed to predict sulphuric acid aerosol formation in typical industrial absorption processes for Gas Cleaning. The underlying model comprises homogeneous nucleation and the growth of a polydisperse droplet collective under the special circumstances of a Gas–liquid contact device where heat and mass transfer processes between the bulk phases take place simultaneously. The model is applied to a hot flue Gas (200 °C) with sulphuric acid concentrations between 5 and 100 mg m −3 (STP) (STP: standard temperature and pressure ) . The simulation yields high droplet number concentrations up to 10 16 m −3 especially for low Gas inlet concentrations of sulphuric acid (5 mg m −3 (STP)), and very small droplet sizes in the range 20–100 nm. The droplet number concentrations decrease and the droplet sizes increase with increasing sulphuric acid inlet concentrations. It is shown that small droplets (
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characterization of sulphuric acid and ammonium sulphate aerosols in wet flue Gas Cleaning processes
Chemical Engineering and Processing, 2008Co-Authors: S Sinanis, Karlheinz SchaberAbstract:Abstract Sulphuric acid aerosols can be formed in wet flue Gas Cleaning processes by spontaneous condensation initiated mainly by homogeneous nucleation. Even at low Gas inlet concentrations of SO 3 (2 mg/m 3 (STP)) aerosol formation can be observed. For the design of absorption processes and sulphuric acid mist precipitators the aerosol characteristic data like mean diameter and number concentration are required for different process conditions and raw Gas concentrations. In the present contribution, a combination of an experimental method with the simulation tool AerCode is described, which permits the determination of the diameter and the number concentration of sulphuric acid aerosols formed in wet flue Gas Cleaning processes. As a result of the extreme azeotropic phase behaviour of the H 2 SO 4 –H 2 O system the mechanism of homogeneous nucleation is predominant for aerosol formation in absorption processes. Furthermore, the influence of soluble and insoluble particles on homogeneous nucleation in the system H 2 SO 4 –H 2 O is shown. The investigation of the influence of insoluble foreign nuclei shows that at high SO 3 raw Gas concentrations >30 mg/m 3 (STP), the mechanism of homogeneous nucleation is predominant. At lower raw Gas concentrations between 2 and 10 mg/m 3 (STP) SO 3 heterogeneous nucleation is the major reason for aerosol formation. Solid (NH 4 ) 2 SO 4 particles that are formed by the reaction between H 2 SO 4 and NH 3 in the Gas phase are used as soluble foreign nuclei. The studies show that aerosol formation is determined by the reaction component whose concentration is below the stoichiometric ratio. It was observed that in the case of an excess of sulphuric acid a decrease of the amount of ammonia leads to an increase of the particle size combined with a decrease in the number concentration. If ammonia is in excess, the decrease in the concentration of ammonia changes neither the particle size nor the number concentration of the aerosol significantly.
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characterization of sulphuric acid and ammonium sulphate aerosols in wet flue Gas Cleaning processes
Chemical Engineering and Processing, 2008Co-Authors: S Sinanis, Karlheinz SchaberAbstract:Abstract Sulphuric acid aerosols can be formed in wet flue Gas Cleaning processes by spontaneous condensation initiated mainly by homogeneous nucleation. Even at low Gas inlet concentrations of SO 3 (2 mg/m 3 (STP)) aerosol formation can be observed. For the design of absorption processes and sulphuric acid mist precipitators the aerosol characteristic data like mean diameter and number concentration are required for different process conditions and raw Gas concentrations. In the present contribution, a combination of an experimental method with the simulation tool AerCode is described, which permits the determination of the diameter and the number concentration of sulphuric acid aerosols formed in wet flue Gas Cleaning processes. As a result of the extreme azeotropic phase behaviour of the H 2 SO 4 –H 2 O system the mechanism of homogeneous nucleation is predominant for aerosol formation in absorption processes. Furthermore, the influence of soluble and insoluble particles on homogeneous nucleation in the system H 2 SO 4 –H 2 O is shown. The investigation of the influence of insoluble foreign nuclei shows that at high SO 3 raw Gas concentrations >30 mg/m 3 (STP), the mechanism of homogeneous nucleation is predominant. At lower raw Gas concentrations between 2 and 10 mg/m 3 (STP) SO 3 heterogeneous nucleation is the major reason for aerosol formation. Solid (NH 4 ) 2 SO 4 particles that are formed by the reaction between H 2 SO 4 and NH 3 in the Gas phase are used as soluble foreign nuclei. The studies show that aerosol formation is determined by the reaction component whose concentration is below the stoichiometric ratio. It was observed that in the case of an excess of sulphuric acid a decrease of the amount of ammonia leads to an increase of the particle size combined with a decrease in the number concentration. If ammonia is in excess, the decrease in the concentration of ammonia changes neither the particle size nor the number concentration of the aerosol significantly.
Serge M A Biollaz - One of the best experts on this subject based on the ideXlab platform.
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production of synthetic natural Gas sng from coal and dry biomass a technology review from 1950 to 2009
Fuel, 2010Co-Authors: Jan Kopyscinski, Tilman J Schildhauer, Serge M A BiollazAbstract:SNG production from coal or biomass is considered again due to rising prices for natural Gas, the wish for less dependency from natural Gas imports and the opportunity of reducing green house Gases by CO2 capture and sequestration. Coal and solid dry biomass (e.g., wood and straw) have to be converted to SNG by thermo-chemical processes (Gasification followed by Gas Cleaning, conditioning, methanation of the producer Gas and subsequent Gas upgrading). During the 1970s, a number of methanation processes have been developed comprising both fixed bed and fluidised bed methanation. Meanwhile several new processes are under development, especially with a focus on the conversion of biomass. While coal based systems usually involve high pressure cold Gas Cleaning steps, biomass based systems require, due to the smaller unit size, different Gas Cleaning strategies. Moreover, the ethylene content of a few percent, typical for methane-rich producer Gas from biomass Gasifiers, is a challenge for the long-term catalyst stability in adiabatic fixed bed methanation due to the inherent high temperatures. This paper reviews the processes developed for the production of SNG from coal during the sixties and seventies and the recent developments for SNG production from coal and from dry biomass.
