Micellar Enhanced Ultrafiltration for Arsenic(V) Removal:  Effect of Main Operating Conditions and Dynamic Modelling

2006 ◽  
Vol 40 (8) ◽  
pp. 2746-2752 ◽  
Author(s):  
F. Beolchini ◽  
F. Pagnanelli ◽  
I. De Michelis ◽  
F. Vegliò
Keyword(s):  
Dynamic Modelling ◽  
Operating Conditions ◽  
Micellar Enhanced Ultrafiltration ◽  
Main Operating

scholarly journals Simulation of a Downdraft Gasifier for Production of Syngas from Different Biomass Feedstocks

2021 ◽  
Vol 5 (2) ◽  
pp. 20
Author(s):  
Mateus Paiva ◽  
Admilson Vieira ◽  
Helder T. Gomes ◽  
Paulo Brito
Keyword(s):  
Modeling And Simulation ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Fuel Gas ◽  
Heating Value ◽  
Downdraft Gasifier ◽  
Process Operation ◽  
Independent Parameters ◽  
Gasification Temperature ◽  
Main Operating

In the evaluation of gasification processes, estimating the composition of the fuel gas for different conditions is fundamental to identify the best operating conditions. In this way, modeling and simulation of gasification provide an analysis of the process performance, allowing for resource and time savings in pilot-scale process operation, as it predicts the behavior and analyzes the effects of different variables on the process. Thus, the focus of this work was the modeling and simulation of biomass gasification processes using the UniSim Design chemical process software, in order to satisfactorily reproduce the operation behavior of a downdraft gasifier. The study was performed for two residual biomasses (forest and agricultural) in order to predict the produced syngas composition. The reactors simulated gasification by minimizing the free energy of Gibbs. The main operating parameters considered were the equivalence ratio (ER), steam to biomass ratio (SBR), and gasification temperature (independent variables). In the simulations, a sensitivity analysis was carried out, where the effects of these parameters on the composition of syngas, flow of syngas, and heating value (dependent variables) were studied, in order to maximize these three variables in the process with the choice of the best parameters of operation. The model is able to predict the performance of the gasifier and it is qualified to analyze the behavior of the independent parameters in the gasification results. With a temperature between 850 and 950 °C, SBR up to 0.2, and ER between 0.3 and 0.5, the best operating conditions are obtained for maximizing the composition of the syngas in CO and H2.

scholarly journals Multibody dynamic modelling of a direct wind turbine drive train

2019 ◽  
Vol 44 (5) ◽  
pp. 519-547
Author(s):  
Saeed Asadi ◽  
Håkan Johansson
Keyword(s):  
Wind Turbine ◽  
Measurement Data ◽  
Dynamic Modelling ◽  
Simulation Software ◽  
Operating Conditions ◽  
Drive Train ◽  
Operational Experience ◽  
Main Bearing ◽  
Wide Range ◽  
Turbine Drive

Wind turbines normally have a long operational lifetime and experience a wide range of operating conditions. A representative set of these conditions is considered as part of a design process, as codified in standards. However, operational experience shows that failures occur more frequently than expected, the costlier of these including failures in the main bearings and gearbox. As modern turbines are equipped with sophisticated online systems, an important task is to evaluate the drive train dynamics from online measurement data. In particular, internal forces leading to fatigue can only be determined indirectly from other locations’ sensors. In this contribution, a direct wind turbine drive train is modelled using the floating frame of reference formulation for a flexible multibody dynamics system. The purpose is to evaluate drive train response based on blade root forces and bedplate motions. The dynamic response is evaluated in terms of main shaft deformation and main bearing forces under different wind conditions. The model was found to correspond well to a commercial wind turbine system simulation software (ViDyn).

scholarly journals Hydrogenation of Nitrobenzene over a Pd/Al2O3Catalyst - Mechanism and Effect of the Main Operating Conditions

2015 ◽  
Vol 38 (9) ◽  
pp. 1625-1636 ◽  
Author(s):  
Clara Sá Couto ◽  
Luis M. Madeira ◽  
Clemente Pedro Nunes ◽  
Paulo Araújo
Keyword(s):  
Operating Conditions ◽  
Main Operating

Oxidation of cosmetic wastewaters with H2O2 using a Fe/γ-Al2O3 catalyst

2010 ◽  
Vol 61 (6) ◽  
pp. 1631-1636 ◽  
Author(s):  
P. Bautista ◽  
A. F. Mohedano ◽  
J. A. Casas ◽  
J. A. Zazo ◽  
J. J. Rodriguez
Keyword(s):  
Space Time ◽  
Operating Conditions ◽  
Peroxide Oxidation ◽  
Sewer System ◽  
Allowable Limit ◽  
Wet Peroxide Oxidation ◽  
Initial Load ◽  
Lower Temperature ◽  
Al2o3 Catalyst ◽  
Main Operating

A catalyst based on Fe supported on γ-Al2O3 has been prepared and tested for catalytic wet peroxide oxidation (CWPO) of cosmetic wastewaters. The influence of the main operating conditions (space-time, temperature, and H2O2 dose) have been investigated. Working with this self-made Fe/γ-Al2O3 catalyst at 85°C, with a space-time of 9.4 kgcat h/kgCOD and a dose of H2O2, corresponding to 0.5 times the theoretical stoichiometric H2O2/COD ratio, a substantial COD reduction (around 80%) has been reached with a complete consumption of H2O2. The locally allowable limit of COD for industrial wastewaters discharge to the municipal sewer system can be achieved at lower temperature and space-time. The catalyst showed a high stability in 100 h time on stream tests, where COD and TOC reductions around 82 and 60%, respectively, were maintained working at 85°C and 9.4 kgcat h/kgCOD space-time. Fe leaching from the catalyst upon that time on stream was lower than 3% of the initial load.

scholarly journals Considerations and complications with "first principles" dynamic modelling of industrial compressors

2021 ◽  
pp. 24-32
Author(s):  
James Jacoby ◽  
Thomas Bailey ◽  
Vitalii Zharikov
Keyword(s):  
First Principles ◽  
Dynamic Modelling ◽  
Simulation Software ◽  
Operating Conditions ◽  
High Fidelity ◽  
Hot Gas ◽  
Front End ◽  
Valve Size ◽  
Vent Valve ◽  
Compressor Performance

Readily available processing hardware and "off-the-shelf" (OTS) simulation software has made "high fidelity" first principles models of both steady and transient states, for both axial and centrifugal industrial compressors, relatively easy to construct. These high-fidelity models are finding their way into "real-time. digital twin" performance monitors, front-end engineering design, and post-design – pre-construction compressor performance evaluation. The compressor models are useful for reliably demonstrating the compressor and – to some degree, based on the complexity of the model – process response to various operating conditions. Once the model is constructed, it is trivial to run a "what-if" analysis of compressor performance to answer questions related to (a) recommendations or validation of the recycle/vent valve size and actuation speed, (b) general piping layout and sizing around the compressor, (c) and hot gas bypass requirements, to name a few. This paper takes a practical approach in discussing the compressor and process parameters necessary for building these dynamic "high-fidelity" industrial-compressor models. We identify compressor inputs and compressor responses that are faithfully modeled by first-principle equations available in the simulation software and those that typically require a compromise between an "ab initio" and data-fitting approximation. We discuss the simulation's tendency to overstate pressure excursions during surge events and understate the compressor operation in the "stonewall" region. We also discuss using the simulator software's compressor-stage enthalpy calculations to predict and quantify the compressor train reverse rotation. We use our broad experience and understanding of the compressor operation and simulation and our experience with the AVEVA™ Dynamic-Simulation "OTS" simulation software as the basis for this discussion.

scholarly journals Model development of integrated CPOx reformer and SOFC stack system

2016 ◽  
Vol 18 (4) ◽  
pp. 41-46 ◽  
Author(s):  
Paulina Pianko-Oprych ◽  
Seyed Mehdi Hosseini ◽  
Zdzislaw Jaworski
Keyword(s):  
Steady State ◽  
Model Development ◽  
Dynamic Modelling ◽  
Integrated System ◽  
Operating Conditions ◽  
System Response ◽  
Dynamic Mode ◽  
Valuable Insight ◽  
Steady State Mode ◽  
Load Variations

Abstract The main purpose of this study was to develop a mathematical model, in a steady state and dynamic mode, of a Catalytic Partial Oxidation (CPOx) reformer – Solid Oxide Fuel Cell (SOFC) stack integrated system in order to assess the system performance. Mass balance equations were written for each component in the system together with energy equation and implemented into the MATLAB Simulink simulation tool. Temperature, gas concentrations, pressure and current density were computed in the steady-state mode and validated against experimental data. The calculated I–V curve matched well the experimental one. In the dynamic modelling, several different conditions including step changes in fuel flow rates, stack voltage as well as temperature values were applied to estimate the system response against the load variations. Results provide valuable insight into the operating conditions that have to be achieved to ensure efficient CPOx performance for fuel processing for the SOFC stack applications.

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