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Shadle, Lawrence J

Publications and source records attributed to Shadle, Lawrence J.

9 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

chapter 40 - Gasification Technologies, "Handbook of Climate Change Mitigation and Adaptation"

Gasification is an enabling technology for the clean-up of fossil and biomass fuels for energy production. A history of gasifier development is told from the perspective of a technology evolving to meet the ever changing market needs. The chemistry and physics of coal conversion includes pyrolysis, combustion, gasification, mineral transformations as well as a discussion of the materials developed to meet the most challenging gasifier applications. Integrated gasification and combined cycle processes are discussed with respect to electrical power production. The distinguishing features for different types of gasifiers are described including fixed bed, fluidized bed, entrained flow, transport gasifiers. The twelve major gasifiers being marketed today are described. The hydrodynamics and kinetics of each are reviewed along with salient differences in performance, such as gas composition, when using a variety of fuels under different conditions. Critical operational features that are discussed include oxidizing media, air or oxygen blown; the system pressure; fuel feed stock; and downstream clean-up. Thermal integration is discussed with respect to its impact on the gasifier performance. Gas clean-up is also considered with respect to the removal of potential pollutants and the shifting to environmentally benign transportation and process fuels.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2013

Image analysis measurements of particle coefficient of restitution for coal gasification applications

New robust Lagrangian computational fluid dynamic (CFD) models are powerful tools that can be used to study the behavior of a diverse population of coal particle sizes, densities, and mineral compositions in entrained gasifiers. By using this approach, the responses of the particles impacting the wall were characterized over a range of velocities (1 to 8 m/s) and incident angles (90 to 20°). Within CFD models, the kinematic coefficient of restitution is the boundary condition defining the particle wall behavior. Four surfaces were studied to simulate the physical conditions of different entrained-flow gasification particle–surface collision scenarios: 1) a flat metal plate 2) a low viscosity silicon adhesive, 3) a high viscosity silicon adhesive, and 4) adhered particles on a flat metal plate with Young's modulus of elasticity ranging from 0.9 to 190 GPa. Entrained flow and drop experiments were conducted with granular coke particles, polyethylene beads and polystyrene pellets. The particle normal and tangential coefficients of restitution were measured using high speed imaging and particle tracking. The measured coefficients of restitution were observed to have a strong dependence on the rebound angles for most of the data. Suitable algebraic expressions for the normal and the tangential component of the coefficient of restitution were developed based upon ANOVA analysis. These expressions quantify the effect of normalized Young's modulus, particle equancy, and relative velocity on the coefficient of restitution. The coefficient of restitution did not have a strong dependence on the particle velocity over the range considered as long as the velocity was above the critical velocity. However, strong correlations were found between the degree of equancy of the particles and the mean coefficient of restitution such that the coefficient of restitution decreased for smaller particle equancies. It was concluded that the degree of equancy and the normalized Young's modulus should be considered in applications such as gasification and other cases involving the impact of non-spherical particles and complex surfaces. Sliding was observed when particles impacted on oblique surfaces; however, the resulting effects were within the range of measurement uncertainties.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2013

CO{sub 2} adsorption: Experimental investigation with kinetics verification and CFD reactor model validation

The National Energy Technology Laboratory is investigating a new process for CO{sub 2} capture from large sources such as utility power generation facilities as an alternative to liquid amine based absorption processes. Many, but not all of these advanced dry processes are based upon sorbents composed of supported polyamines. In this analysis, experiments have been conducted in a small facility at different temperatures and compared to CFD reactor predictions using kinetics obtained from TGA tests. This particular investigation compares the predicted performance and the experimental performance of one of these new class of sorbents in a fluidized bed reactor. In the experiment, the sorbent absorbs CO{sub 2} from simulated flue gas in a riser reactor, separates the carbonated particles from the de-carbonated flue gas in a cyclone and then regenerates the sorbent, creating a concentrated stream of pure CO{sub 2} for sequestration. In this work, experimental measurements of adsorption are compared to predictions from a 3-dimensional non-isothermal reacting multiphase flow model. The effects of the gas flow rate and reactor temperature are explored. It is shown that the time duration for CO{sub 2} adsorption decreased for an increase in the gas flow. The details of the experimental facility and the model as well as the comparative analysis between the data and the simulation results are discussed.

01 COAL, LIGNITE, AND PEAT↗