Improved Switchgrass Gasification Using Molten Carbonate Salts

2011 ◽  
Author(s):  
Brandon J. Hathaway ◽  
Masanori Honda ◽  
Jane H. Davidson
Keyword(s):  
Heat Transfer ◽  
Reaction Rates ◽  
Gas Production ◽  
Molten Carbonate ◽  
Syngas Production ◽  
Concentrated Solar Energy ◽  
Product Composition ◽  
Reactivity Indexes ◽  
Production Of Hydrogen ◽  
Carbonate Salts

The use of concentrated solar energy for gasification of biomass is an efficient means for production of hydrogen rich synthesis gas. Utilizing molten alkali-carbonate salts as a reaction and heat transfer medium offers enhanced heat transfer, faster kinetics, and stability for solar transients. The effect of the molten salts on gasification of switchgrass is examined in terms of the reaction rates and product composition. Experiments were carried out in an electrically heated molten salt reactor. Switchgrass was gasified with steam at 1200 K in an inert gas and with salt. Reactivity indexes were calculated from measured gas production rates. Product composition was established via mass spectrometry. In salt, the total useful syngas production increased by 30% while reducing net carbon dioxide production. Reactivity increased 81%. Secondary products, in the form of condensable tar and unreacted char, were reduced by 77%.

Solar Gasification of Biomass: Kinetics of Pyrolysis and Steam Gasification in Molten Salt

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Brandon J. Hathaway ◽  
Jane H. Davidson ◽  
David B. Kittelson
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Ternary Eutectic ◽  
Reaction Rates ◽  
Steam Gasification ◽  
Molten Carbonate ◽  
Concentrated Solar Energy ◽  
Production Of Hydrogen ◽  
Carbonate Salts ◽  
Kinetics Of

The use of concentrated solar energy as a heat source for pyrolysis and gasification of biomass is an efficient means for production of hydrogen rich synthesis gas. Utilizing molten alkali carbonate salts as a reaction and heat transfer media promises enhanced stability to solar transients and faster reaction rates. The present study establishes and compares the reaction kinetics of pyrolysis and gasification of cellulose from 1124 K to 1235 K in an electric furnace. Data are presented in an inert environment and in a bath of a ternary eutectic blend of lithium, potassium, and sodium carbonate salts. Arrhenius rate expressions are derived from the data supported by a numerical model of heat and mass transfer. The molten salt increases the rate of pyrolysis by 74% and increases gasification rates by more than an order of magnitude while promoting a product gas composition nearer to thermodynamic equilibrium predictions. These results justify using molten carbonate salts as a combined catalyst and heat transfer media for solar gasification.

Solar Gasification of Biomass: Kinetics of Pyrolysis and Steam Gasification in Molten Salt

2010 ◽  
Author(s):  
Brandon J. Hathaway ◽  
Jane H. Davidson ◽  
David B. Kittelson
Keyword(s):  
Molten Salt ◽  
Average Rate ◽  
Reaction Rates ◽  
Steam Gasification ◽  
Reactivity Index ◽  
Concentrated Solar Energy ◽  
Production Of Hydrogen ◽  
Order Of Magnitude ◽  
Carbonate Salts ◽  
Kinetics Of

The use of concentrated solar energy for pyrolysis and gasification of biomass is an efficient means for production of hydrogen rich synthesis gas. Utilizing molten alkali-carbonate salts as a reaction and heat transfer media offers enhanced stability and higher reaction rates to these solar processes. To establish the reaction kinetics, experiments were carried out in an electrically heated molten salt reactor. Cellulose or activated charcoal were pyrolyzed or gasified with steam from 1124 K to 1235 K with and without salt. Arrhenius rate expressions are derived from the data supported by a numerical model of heat and mass transfer. The average rate of the reactions in molten salt, as measured by their reactivity index, is increased by 70% for pyrolysis and by an order of magnitude for steam gasification.

scholarly journals Sonochemical and Sonoelectrochemical Production of Energy Materials

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 284
Author(s):  
Faranak Foroughi ◽  
Jacob J. Lamb ◽  
Odne S. Burheim ◽  
Bruno G. Pollet
Keyword(s):  
Reaction Rates ◽  
Surface Cleaning ◽  
Energy Materials ◽  
Fast Reaction ◽  
Ultrasound Frequency ◽  
Production Of Hydrogen ◽  
Scientists And Engineers ◽  
Electrocatalyst Materials ◽  
Made In ◽  
Semiconductor Photocatalyst

Sonoelectrochemistry is the combination of ultrasound and electrochemistry which provides many advantages in electrochemistry, such as fast reaction rates, surface cleaning and activation, and increased mass transport at an electrode. Due to the advantages, some efforts have been made in order to benefit sonoelectrochemistry in the field of energy and environmental engineering. This review paper highlights the developed progress of the application of sonoelectrochemistry in the production of hydrogen, electrocatalyst materials and electrodes for fuel cells and semiconductor photocatalyst materials. This review also provides the experimental methods that are utilized in several sonoelectrochemical techniques, such as different set-ups generally used for the synthesis of energy-related materials. Different key parameters in the operation of sonoelectrochemical synthesis including ultrasonication time, ultrasound frequency and operation current have been also discussed. There are not many research articles on the sonoelectrochemical production of materials for supercapacitors and water electrolyzers which play crucial roles in the renewable energy industry. Therefore, at the end of this review, some articles which have reported the use of ultrasound for the production of electrocatalysts for supercapacitors and electrolyzers have been reviewed. The current review might be helpful for scientists and engineers who are interested in and working on sonoelectrochemistry and electrocatalyst synthesis for energy storage and energy conversion.

Experimental Parameter Study on Synthesis Gas Production by Steam-Oxygen Fluidized Bed Gasification of Sewage Sludge

2021 ◽  
Vol 11 (2) ◽  
pp. 579
Author(s):  
Max Schmid ◽  
Selina Hafner ◽  
Günter Scheffknecht
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Experimental Parameter ◽  
Space Velocity ◽  
Phosphate Fertilizer ◽  
Gas Production ◽  
Raw Material ◽  
Parameter Study ◽  
Syngas Production ◽  
Fuels And Chemicals

The conversion of biogenic residues to fuels and chemicals via gasification and synthesis processes is a promising pathway to replace fossil carbon. In this study, the focus is set on sewage sludge gasification for syngas production. Experiments were carried out in a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agent. In-situ produced sewage sludge ash was used as bed material. The sensitivity of the key operation parameters gasifier temperature, oxygen ratio, steam to carbon ratio, and the space velocity on the syngas composition (H2, CO, CO2, CH4, CxHy, H2S, COS, NH3, and tars) was determined. The results show that the produced syngas has high H2 and CO concentrations of up to 0.37 m3 m−3 and 0.18 m3 m−3, respectively, and is thus suitable for synthesis of fuels and chemicals. By adjusting the steam to carbon ratio, the syngas’ H2 to CO ratio can be purposely tailored by the water gas shift reaction for various synthesis products, e.g., synthetic natural gas (H2/CO = 3) or Fischer–Tropsch products (H2/CO = 2). Also, the composition and yields of fly ash and bed ash are presented. Through the gasification process, the cadmium and mercury contents of the bed ash were drastically reduced. The ash is suitable as secondary raw material for phosphorous or phosphate fertilizer production. Overall, a broad database was generated that can be used for process simulation and process design.

scholarly journals Mass and Heat Transfer Coefficients in Automotive Exhaust Catalytic Converter Channels

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 507
Author(s):  
Chrysovalantis C. Templis ◽  
Nikos G. Papayannakos
Keyword(s):  
Heat Transfer ◽  
Flow Reactor ◽  
Catalytic Converter ◽  
Reaction Rates ◽  
Cfd Model ◽  
Automotive Exhaust ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Wide Range ◽  
Mass And Heat Transfer

Mass and heat transfer coefficients (MTC and HTC) in automotive exhaust catalytic monolith channels are estimated and correlated for a wide range of gas velocities and prevailing conditions of small up to real size converters. The coefficient estimation is based on a two dimensional computational fluid dynamic (2-D CFD) model developed in Comsol Multiphysics, taking into account catalytic rates of a real catalytic converter. The effect of channel size and reaction rates on mass and heat transfer coefficients and the applicability of the proposed correlations at different conditions are discussed. The correlations proposed predict very satisfactorily the mass and heat transfer coefficients calculated from the 2-D CFD model along the channel length. The use of a one dimensional (1-D) simplified model that couples a plug flow reactor (PFR) with mass transport and heat transport effects using the mass and heat transfer correlations of this study is proved to be appropriate for the simulation of the monolith channel operation.

scholarly journals Photodeposition of Ag Nanocrystals onto TiO2 Nanotube Platform for Enhanced Water Splitting and Hydrogen Gas Production

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Nur Aimi Jani ◽  
Choonyian Haw ◽  
Weesiong Chiu ◽  
Saadah Abdul Rahman ◽  
Poisim Khiew ◽  
...  
Keyword(s):  
Water Splitting ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Current Work ◽  
Plasmonic Resonance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Production Of Hydrogen ◽  
Production Activity ◽  
Ag Ncs

Current work reports the study of Ag nanocrystals (NCs) decorated doubly anodized (DA) TiO2 nanotubes (NTs) thin film as an efficient photoelectrode material for water splitting and photocatalytic hydrogen gas production. DA process has been shown to be capable of producing less defective NTs and creating additional spacious gaps in between NT bundles to allow efficient and uniform integration of Ag NCs. By employing photoreduction method, Ag NCs can be deposited directly onto NTs, where the size and density of coverage can be maneuvered by merely varying the concentration of Ag precursors. Field emission scanning electron microscope (FESEM) images show that the Ag NCs with controllable size are homogeneously decorated onto the walls of NTs with random yet uniform distribution. X-ray diffraction (XRD) results confirm the formation of anatase TiO2 NTs and Ag NCs, which can be well indexed to standard patterns. The decoration of metallic Ag NCs onto the surface of NTs demonstrates a significant enhancement in the photoconversion efficiency as compared to that of pristine TiO2 NTs. Additionally, the as-prepared nanocomposite film also shows improved efficiency when used as a photocatalyst platform in the production of hydrogen gas. Such improvement in the performance of water splitting and photocatalytic hydrogen gas production activity can be credited to the surface plasmonic resonance of Ag NCs present on the surface of the NTs, which renders improved light absorption and better charge separation. The current work can serve as a model of study for designing more advanced nanoarchitecture photoelectrode for renewable energy application.

Experimental Investigation of a Packed-Bed Solar Reactor for the Steam-Gasification of Biomass Charcoal

2008 ◽  
Author(s):  
Nicolas Piatkowski ◽  
Christian Wieckert ◽  
Aldo Steinfeld
Keyword(s):  
Calorific Value ◽  
Packed Bed ◽  
Energy Conversion Efficiency ◽  
Steam Gasification ◽  
Solar Simulator ◽  
High Quality ◽  
Syngas Production ◽  
Solar Reactor ◽  
Graphite Plate ◽  
Concentrated Solar Energy

Gasification of coal, biomass, and other carbonaceous materials for high-quality syngas production is considered using concentrated solar energy as the source of high-temperature process heat. The solar reactor consists of two cavities separated by a SiC-coated graphite plate, with the upper one serving as the radiative absorber and the lower one containing the reacting packed bed that shrinks as the reaction progresses. A 5-kW prototype reactor with an 8 cm-depth, 14.3 cm-diameter cylindrical bed was fabricated and tested in the High-Flux Solar Simulator at PSI, subjected to solar flux concentrations up to 2300 suns. Beech charcoal was used as a model feedstock and converted into high-quality syngas (predominantly H2 and CO) with packed-bed temperatures up to 1500 K, an upgrade factor of the calorific value of 1.33, and an energy conversion efficiency of 29%. Pyrolysis was evident through the evolution of higher gaseous hydrocarbons during heating of the packed bed. The engineering design, fabrication, and testing of the solar reactor are described.

scholarly journals Application of Ozone and Oxygen to Reduce Chemical Oxygen Demand and Hydrogen Sulfide from a Recovered Paper Processing Plant

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Patricia A. Terry
Keyword(s):  
Hydrogen Sulfide ◽  
Chemical Oxygen Demand ◽  
Contact Time ◽  
Oxygen Demand ◽  
Gas Production ◽  
Injection System ◽  
Processing Plant ◽  
Short Contact Time ◽  
Production Of Hydrogen ◽  
Fox River

A pilot study was performed at the Fox River Fiber recovered paper processing company in DePere, Wisconsin, to determine the extent to which injection of oxygen and ozone could reduce the high chemical oxygen demand, COD, in the effluent and the effectiveness of the ozone/oxygen stream in suppressing production of hydrogen sulfide gas in downstream sewage lines. Adaptive Ozone Solutions, LLC, supplied the oxygen/ozone generation and injection system. Samples were analyzed both before and after oxygen/ozone injection. Hydrogen sulfide gas was continuously monitored at sewer stations downstream of Fox River Fiber. Results showed that with a very short contact time, effluent COD was reduced by over 15%. A simple kinetic model predicts that a contact time of fewer than 30 minutes could reduce COD by as much as 60%. In addition, downstream hydrogen sulfide gas production in the sewage mains was also better controlled, such that costly Bioxide applications could be reduced.

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