scholarly journals Potential for bed-material entrainment in selected streams of the Edwards Plateau - Edwards, Kimble, and Real Counties, Texas, and vicinity

2008 ◽  
Author(s):  
Franklin T. Heitmuller ◽  
William H. Asquith
Keyword(s):  
Edwards Plateau ◽  
Bed Material

scholarly journals Effect of biomass fuel ash and bed material on the product gas composition in DFB steam gasification

Energy ◽  
2021 ◽  
Vol 219 ◽  
pp. 119650
Author(s):  
K. Fürsatz ◽  
J. Fuchs ◽  
F. Benedikt ◽  
M. Kuba ◽  
H. Hofbauer
Keyword(s):  
Steam Gasification ◽  
Biomass Fuel ◽  
Gas Composition ◽  
Product Gas ◽  
Fuel Ash ◽  
Bed Material

scholarly journals Parametric Study on the Adjustability of the Syngas Composition by Sorption-Enhanced Gasification in a Dual-Fluidized Bed Pilot Plant

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 399
Author(s):  
Selina Hafner ◽  
Max Schmid ◽  
Günter Scheffknecht
Keyword(s):  
Fluidized Bed ◽  
Ghg Emissions ◽  
Space Velocity ◽  
Synthesis Process ◽  
Wood Pellets ◽  
High Hydrogen ◽  
Syngas Production ◽  
Dual Fluidized Bed ◽  
Bed Material ◽  
Gasification Temperature

Finding a way for mitigating climate change is one of the main challenges of our generation. Sorption-enhanced gasification (SEG) is a process by which syngas as an important intermediate for the synthesis of e.g., dimethyl ether (DME), bio-synthetic natural gas (SNG) and Fischer–Tropsch (FT) products or hydrogen can be produced by using biomass as feedstock. It can, therefore, contribute to a replacement for fossil fuels to reduce greenhouse gas (GHG) emissions. SEG is an indirect gasification process that is operated in a dual-fluidized bed (DFB) reactor. By the use of a CO2-active sorbent as bed material, CO2 that is produced during gasification is directly captured. The resulting enhancement of the water–gas shift reaction enables the production of a syngas with high hydrogen content and adjustable H2/CO/CO2-ratio. Tests were conducted in a 200 kW DFB pilot-scale facility under industrially relevant conditions to analyze the influence of gasification temperature, steam to carbon (S/C) ratio and weight hourly space velocity (WHSV) on the syngas production, using wood pellets as feedstock and limestone as bed material. Results revealed a strong dependency of the syngas composition on the gasification temperature in terms of permanent gases, light hydrocarbons and tars. Also, S/C ratio and WHSV are parameters that can contribute to adjusting the syngas properties in such a way that it is optimized for a specific downstream synthesis process.

scholarly journals Experimental Investigation of Oxygen Carrier Aided Combustion (OCAC) with Methane and PSA Off-Gas

2020 ◽  
Vol 11 (1) ◽  
pp. 210
Author(s):  
Viktor Stenberg ◽  
Magnus Rydén ◽  
Tobias Mattisson ◽  
Anders Lyngfelt
Keyword(s):  
Oxygen Carrier ◽  
Silica Sand ◽  
Fuel Conversion ◽  
Fuel Gas ◽  
Bed Temperature ◽  
Bed Materials ◽  
Distribution Plate ◽  
Bed Material ◽  
Gas Conversion ◽  
No Emissions

Oxygen carrier aided combustion (OCAC) is utilized to promote the combustion of relatively stable fuels already in the dense bed of bubbling fluidized beds by adding a new mechanism of fuel conversion, i.e., direct gas–solid reaction between the metal oxide and the fuel. Methane and a fuel gas mixture (PSA off-gas) consisting of H2, CH4 and CO were used as fuel. Two oxygen carrier bed materials—ilmenite and synthetic particles of calcium manganate—were investigated and compared to silica sand, an in this context inert bed material. The results with methane show that the fuel conversion is significantly higher inside the bed when using oxygen carrier particles, where the calcium manganate material displayed the highest conversion. In total, 99.3–99.7% of the methane was converted at 900 °C with ilmenite and calcium manganate as a bed material at the measurement point 9 cm above the distribution plate, whereas the bed with sand resulted in a gas conversion of 86.7%. Operation with PSA off-gas as fuel showed an overall high gas conversion at moderate temperatures (600–750 °C) and only minor differences were observed for the different bed materials. NO emissions were generally low, apart from the cases where a significant part of the fuel conversion took place above the bed, essentially causing flame combustion. The NO concentration was low in the bed with both fuels and especially low with PSA off-gas as fuel. No more than 11 ppm was detected at any height in the reactor, with any of the bed materials, in the bed temperature range of 700–750 °C.

Effects of Increasing Inlet Velocities and Side Port Air Injection on a Biomass Fluidizing Bed

2010 ◽  
Author(s):  
Mirka Deza ◽  
Francine Battaglia
Keyword(s):  
Complex Geometry ◽  
Air Flow ◽  
Three Dimensional ◽  
Air Injection ◽  
Single Side ◽  
X Ray Computed ◽  
Bed Material ◽  
Solid Distribution ◽  
Side Port ◽  
Three Dimensional Simulations

Fluidized beds are being used in practice to gasify biomass to create producer gas, a flammable gas that can be used for process heating. However, recent literature has identified the need to better understand and characterize biomass fluidization hydrodynamics, and computational fluid dynamics (CFD) is one approach in this effort. Previous work by the authors considered the validity of using two-dimensional versus three-dimensional simulations to model a cold-flow fluidizing biomass bed configured with a single side port air injection. The side port is introduced to inject air and promote mixing within the bed. Comparisons with experiments indicated that three-dimensional simulations were necessary to capture the fluidization behavior for the more complex geometry. This paper considers the effects of increasing fluidization air flow and side port air flow on the homogeneity of the bed material in a 10.2 cm diameter fluidized bed. Two air injection ports diametrically opposed to each other are also considered to determine their effects on fluidization hydrodynamics. Whenever possible, the simulations are compared to experimental data of time-averaged local gas holdup obtained using X-ray computed tomography. This study will show that increasing the fluidization and side port air flows contribute to a more homogeneous bed. Furthermore, the introduction of two side ports results in a more symmetric gas-solid distribution.

Predation of Rio Grande Wild Turkey Nests on the Edwards Plateau, Texas

2008 ◽  
Vol 120 (4) ◽  
pp. 906-910 ◽  
Author(s):  
Justin Z. Dreibelbis ◽  
Kyle B. Melton ◽  
Ray Aguirre ◽  
Bret A. Collier ◽  
Jason Hardin ◽  
...  
Keyword(s):  
Rio Grande ◽  
Wild Turkey ◽  
Edwards Plateau ◽  
Rio Grande Wild Turkey
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