13 research outputs found

    Analysis of melt blowing dies using computational fluid dynamics .

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    For a single annular jet and the blunt slot die, a previously developed rheological model was used to predict the fiber diameter, velocity, and temperature. Then, these were used to set boundary conditions in simulations to study the effect of the fiber on the air profiles. Close to the fiber edge, the interactions between the air and fiber are important.Computational Fluid Dynamics (CFD) was used to study the air flow from different types of melt blowing dies. Specifically, the types of dies studied include Exxon slot dies, Schwarz multihole dies, and swirl dies. For the slot dies, the Reynolds Stress Model with modifications matched the experimentally measured velocity profiles. After the experimental measurements were matched, the RSM was used to study the effect of changing the angle between the air jets and the die face. Simulations were completed for melt blowing dies that have not been tested experimentally. Decreasing this angle changed the centerline velocity profile. For sharp slot dies, the effect of the nose piece placement was also examined. The more inset above the die face the nose piece, the higher the maximum centerline air velocity. However, the centerline turbulence intensity also increased. Non-isothermal simulations were run for all slot die geometries to study the effect of the jet geometry on the temperature profiles. The Schwarz melt blowing die was also examined. The k-epsilon turbulence model was used to simulate the air flow from this die. The spacing between the annular jets was changed, and the effect of the jet spacing on the centerline velocity, temperature decay, and turbulence was studied. Finally, the isothermal air flow from a swirl melt blowing die was measured experimentally and simulated using CFD

    Evaluation of Solid Sorbents As A Retrofit Technology for CO{sub 2} Capture from Coal-Fired Power Plants

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    Final technical report documenting research to study the viability of solid-based sorbents for CO2 capture

    EVALUATION OF SOLID SORBENTS AS A RETROFIT TECHNOLOGY FOR CO2 CAPTURE FROM COAL-FIRED POWER PLANTS

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    Through a U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) funded cooperative agreement DE-NT0005649, ADA Environmental Solutions (ADA) has begun evaluating the use of solid sorbents for CO{sub 2} capture. The project objective was to address the viability and accelerate development of a solid-based CO{sub 2} capture technology. To meet this objective, initial evaluations of sorbents and the process/equipment were completed. First the sorbents were evaluated using a temperature swing adsorption process at the laboratory scale in a fixed-bed apparatus. A slipstream reactor designed to treat flue gas produced by coal-fired generation of nominally 1 kWe was designed and constructed, which was used to evaluate the most promising materials on a more meaningful scale using actual flue gas. In a concurrent effort, commercial-scale processes and equipment options were also evaluated for their applicability to sorbent-based CO{sub 2} capture. A cost analysis was completed that can be used to direct future technology development efforts. ADA completed an extensive sorbent screening program funded primarily through this project, DOE NETL cooperative agreement DE-NT0005649, with support from the Electric Power Research Institute (EPRI) and other industry participants. Laboratory screening tests were completed on simulated and actual flue gas using simulated flue gas and an automated fixed bed system. The following types and quantities of sorbents were evaluated: 87 supported amines; 31 carbon based materials; 6 zeolites; 7 supported carbonates (evaluated under separate funding); and 10 hydrotalcites. Sorbent evaluations were conducted to characterize materials and down-select promising candidates for further testing at the slipstream scale. More than half of the materials evaluated during this program were supported amines. Based on the laboratory screening four supported amine sorbents were selected for evaluation at the 1 kW scale at two different field sites. ADA designed and fabricated a slipstream pilot to allow an evaluation of the kinetic behavior of sorbents and provide some flexibility for the physical characteristics of the materials. The design incorporated a transport reactor for the adsorber (co-current reactor) and a fluidized-bed in the regenerator. This combination achieved the sorbent characterization goals and provided an opportunity to evaluate whether the potential cost savings associated with a relatively simple process design could overcome the sacrifices inherent in a co-current separation process. The system was installed at two field sites during the project, Luminant's Martin Lake Steam Electric Station and Xcel Energy's Sherburne County Generating Station (Sherco). Although the system could not maintain continuous 90% CO{sub 2} removal with the sorbents evaluated under this program, it was useful to compare the CO{sub 2} removal properties of several different sorbents on actual flue gas. One of the supported amine materials, sorbent R, was evaluated at both Martin Lake and Sherco. The 1 kWe pilot was operated in continuous mode as well as batch mode. In continuous mode, the sorbent performance could not overcome the limitations of the cocurrent adsorbent design. In batch mode, sorbent R was able to remove up to 90% CO{sub 2} for several cycles. Approximately 50% of the total removal occurred in the first three feet of the adsorption reactor, which was a transport reactor. During continuous testing at Sherco, CO{sub 2} removal decreased to approximately 20% at steady state. The lack of continuous removal was due primarily to the combination of a co-current adsorption system with a fluidized bed for regeneration, a combination which did not provide an adequate driving force to maintain an acceptable working CO{sub 2} capacity. In addition, because sorbent R consisted of a polymeric amine coated on a silica substrate, it was believed that the 50% amine loaded resulted in mass diffusion limitations related to the CO{sub 2} uptake rate. Three additional supported amine materials, sorbents AX, F, and BN, were selected for evaluation using the 1 kW pilot at Sherco. Sorbent AX was operated in batch mode and performed similarly to sorbent R (i.e. could achieve up to 90% removal when given adequate regeneration time). Sorbent BN was not expected to be subject to the same mass diffusion limitations as experienced with sorbent R. When sorbent BN was used in continuous mode the steady state CO{sub 2} removal was approximately double that of sorbent R, which highlighted the importance of sorbents without kinetic limitations

    Conference Program

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