Solution of population balance equations using the direct quadrature method of moments

Application of the direct quadrature method of moments to polydisperse gas–solid fluidized beds

Implementation of the Quadrature Method of Moments in CFD codes for aggregation-breakage problems

Hybrid Method of Moments for modeling soot formation and growth

Modelling of hydrate formation kinetics: State-of-the-art and future directions

Although use of computational fluid dynamics (CFD) for simulating precipitation (and particulate systems in general) is becoming a standard approach, a number of issues still need to be addressed. One major problem is the computational expense of coupling a standard discretized population balance (DPB) with a CFD code, as this approach requires the solution of an intractably large number of transport equations. In this work the quadrature method of moments (QMOM) is tested for size-dependent growth and aggregation. The QMOM is validated by comparison with both Monte Carlo simulations and analytical solutions using several functional forms for the aggregation kernel. Moreover, model predictions are compared with a DPB to compare accuracy, computational time, and the number of scalars involved. Analysis of the relative performance of various methods for treating aggregation provides readers with useful information about the range of application and possible limitations.

Quadrature method of moments for population‐balance equations

Quadrature method of moments for population balances in CFD applications: comparison with experimental data

iv CHAPTER 1: GENERAL INTRODUCTION 1 CHAPTER 2: BASIC CONCEPTS 7 CHAPTER 3: SCALE-UP OF AQUEOUS REDUCTIVE 32 PRECIPITATION OF PALLADIUM METAL CHAPTER 4: VALIDATION OF THE QUADRATURE 82 METHOD OF MOMENTS FOR AGGREGATION PROCESSES CHAPTER 5: INVESTIGATION OF THE PRECIPITATION 92 OF ANILINE HYDROCHLORIDE IN CHLOROBENZENE: DETERMINATION OF PRECIPITATION KINETICS AND INVESTIGATION OF THE REACTION IN TAYLOR-COUETTE FLOW CHAPTER 6: GENERAL CONCLUSIONS 132 APPENDIX 135 REFERENCES 144 ACKNOWLEDGEMENTS 150

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2191&context=rtd

Particle size prediction in reactive precipitation processes

Palladium used at Savannah River (SR) for process tritium storage is currently obtained from a commercial source In order to understand the processes involved in preparing this material, SR is supporting investigations into the chemical reactions used to synthesize this material The material specifications are shown in Table 1 An improved understanding of the chemical processes should help to guarantee a continued reliable source of Pd in the future As part of this evaluation, a work-for-others contract between Westinghouse Savannah River Company and Ames Laboratory (AL) was initiated During FY98, the process for producing Pd powder developed in 1986 by Dan Grove of Mound Applied Technologies, USDOE (the Mound muddy water process) was studied to understand the processing conditions that lead to changes in morphology in the final product During FY99 and FY00, the process for producing Pd powder that has been used previously at Sandia and Los Alamos National Laboratories (the Sandia/LANL process) was studied to understand the processing conditions that lead to changes in the morphology of the final Pd product During FY01, scale-up of the process to batch sizes greater than 600 grams of Pd using a 20-gallon Pfaudler reactor was conducted by the Iowa State University (ISU) Chemical Engineering Department This report summarizes the results of FY99-FY01 Pd processing work done at AL and ISU using the Sandia/LANL process In the Sandia/LANL process, Pd is dissolved in a mixture of nitric and hydrochloric acids A number of chemical processing steps are performed to yield an intermediate species, diamminedichloropalladium (Pd(NH{sub 3}){sub 2}Cl{sub 2}, or DADC-Pd), which is isolated In the final step of the process, the Pd(NH{sub 3}){sub 2}Cl{sub 2} intermediate is subsequently redissolved, and Pd is precipitated by the addition of a reducing agent (RA) mixture of formic acid and sodium formate It is at this point that the morphology of the Pd product is determined During FY99 and FY00, a study of how the characteristics of the Pd are affected by changes in processing conditions including the RA/Pd molar ratio, Pd concentration, mole fraction of formic acid (mf-FA) in the RA solution, reaction temperature, and mixing was performed These parameters all had significant effects on the resulting values of the tap density (TD), BET surface area (SA), and Microtrac particle size (PS) distribution for the Pd samples These effects were statistically modeled and fit in order to determine ranges of predicted experimental conditions that resulted in material that meets the requirements for the Pd powder to be used at SR Although not statistically modeled, the method and rate of addition of the RA and the method and duration of stirring were shown to be significant factors affecting the product morphology Instead of producing an additional statistical fit and due to the likely changes anticipated during scale-up of this processing procedure, these latter conditions were incorporated into a reproducible practical method of synthesis Palladium powder that met the SR specifications for TD, BET SA, and Microtrac PS was reliably produced at batch sizes ranging from 25-100 grams In FY01, scale-up of the Sandia/LANL process was investigated by the ISU Chemical Engineering Department for the production of 600-gram batches of Pd Palladium that meets the SR specifications for TD, BET SA, and Microtrac PS has been produced using the Pfaudler reactor, and additional processing batches will be done during the remainder of FY01 to investigate the range of conditions that can be used to produce Pd powder within specifications Palladium product samples were analyzed at AL and SR to determine TD and at SR to determine BET SA, Microtrac PS distribution, and Pd nodule size and morphology by scanning electron microscopy (SEM)

/pdf/scale-up-of-palladium-powder-production-process-for-use-in-2kosgqtjm4.pdf

Scale-Up of Palladium Powder Production Process for Use in the Tritium Facility at Westinghouse, Savannah River, SC/Summary of FY99-FY01 Results for the Preparation of Palladium Using the Sandia/LANL Process

Jesse T. Pikturna

Papers

Quadrature method of moments for population‐balance equations

Quadrature method of moments for population balances in CFD applications: comparison with experimental data

Particle size prediction in reactive precipitation processes

Scale-Up of Palladium Powder Production Process for Use in the Tritium Facility at Westinghouse, Savannah River, SC/Summary of FY99-FY01 Results for the Preparation of Palladium Using the Sandia/LANL Process