James Spenik

One-Dimensional Modeling and Measurement of Pulsating Gas-Solid Flow in Tubes

Abstract Pulsating turbulent gas-particle flow in a circular tube is investigated by both experimental and numerical methods. In experiments, the ensemble averaged centerline gas and particle velocities ate measured by using laser Doppler anemometry. The amplitude and the frequency of pulsations are controlled via the diameter and the RPM of a rotating butterfly valve. It was found that significant variations could be obtained along the axial position in the amplitude and the phase of the fluid velocity deviation from its mean. Both the amplitude and the phase shift behavior was a function of the imposed pulsating frequency and amplitude. Particle velocity measurements showed that the slip velocities between the fluid and particles are dependent on frequency and position along the axial direction. The experiments are simulated using a one-dimensional transient model which consists of one-dimensional compressible flow equations in an Eulerian, and particle momentum equation in a Lagrangian frame of referen...

CO2 Adsorption: Experimental Investigation and CFD Reactor Model Validation

The National Energy Technology Laboratory is investigating a new process for CO2 capture from large sources such as utility power generation facilities as an alternative to liquid amine based adsorption processes. Many of these advanced dry processes are based upon sorbents composed of supported polyamines. In this analysis, experiments have been conducted in a laboratory-scale fluidized bed reactor and compared to CFD reactor predictions using kinetics obtained from TGA tests. Batch experiments were conducted by flowing a mixture of CO2, H2O, and N2 (simulated flue gas) through a fluidized bed of sorbent material. The exit gas composition time series data is compared to CFD simulations using a 3-dimensional nonisothermal reacting multiphase flow model. The effects of the gas flow rate, distributor design, and particle size are explored through the CFD simulations. It is shown that the time duration for CO2 adsorption decreased for an increase in the gas flow. Fluid bed hydrodynamics indicated that there were regions in the reactor where the inert FCC particles segregated and defluidized; without adversely affecting the capacity of the sorbent to adsorb CO2. The details of the experimental facility and the model as well as the comparative analysis between the data and the simulation results are discussed.