scholarly journals Numerical optimization of a waste-to-energy plant's operating parameters using CFD

2011 ◽  
Vol 15 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Miran Kapitler ◽  
Niko Samec ◽  
Filip Kokalj
Keyword(s):  
Combustion Process ◽  
Operating Conditions ◽  
Environmental Engineering ◽  
Waste To Energy ◽  
Pollutant Emissions ◽  
Operating Parameters ◽  
Plant Design ◽  
Energy Plant ◽  
Computational Work ◽  
Mass Flow Rates

Institute for power, process and environmental engineering, Laboratory for combustion and Environmental engineering, Faculty of Mechanical Engineering, University of Maribor, Republic of Slovenia The combustion process for using municipal solid waste as a fuel within a waste to energy plant calls for a detailed understanding of the following phenomena. Firstly, this process depends on many input parameters such as proximate and ultimate analyses, the season of the year, primary and secondary inlet air velocities and, secondly, on output parameters such as the temperatures or mass-flow rates of the combustible products. The variability and mutual dependence of these parameters can be difficult to manage in practice. Another problem is how these parameters can be tuned to achieving optimal combustible conditions with minimal pollutant emissions, during the plant-design phase. in order to meet these goals, a waste-to-energy plant with bed combustion was investigated by using computational fluid-dynamics approach. The adequate variable input boundary conditions based on the real measurement are used and the whole computational work is updated using real plant geometry and the appropriate turbulence, combustion, or heat transfer models. The operating parameters were optimized on output parameters through a trade-off study. The different operating conditions were varied and the combustible products were predicted and visualized. Finally, the response charts and matrix among the input and output parameters during the optimization process are presented, which monitored the dependence among these parameters.

Numerical Optimization of a Waste-to-Energy Plant Under Different Operating Conditions

2011 ◽  
Author(s):  
Niko Samec ◽  
Miran Kapitler ◽  
Filip Kokalj
Keyword(s):  
Numerical Optimization ◽  
Flow Direction ◽  
Input Parameter ◽  
Combustion Process ◽  
Operating Conditions ◽  
Waste To Energy ◽  
Pollutant Emissions ◽  
Plant Design ◽  
Energy Plant ◽  
Input Parameters

The combustion process for using municipal solid waste (MSW) as a fuel within a waste-to-energy plant calls for a detailed understanding of the following phenomena. Firstly, this process depends on many input parameters such as MSW proximate and ultimate analysis, the season of the year, primary and secondary air-inlet velocity and, secondly, on output parameters such as the temperatures or mass-flow rates (MFR) of the combustible products. The variability and mutual dependence of these parameters can be difficult to manage in practice. Moreover, another problem is how these parameters can be tuned to achieving optimal combustion with minimal pollutant emissions during the initial plant-design phase. In order to meet these goals, a waste-to-energy plant with bed-combustion was investigated by using a computational fluid dynamics (CFD) approach with ANSYS CFX 12.0 code within a WORKBENCH 2 environment. In this paper, the adequate variable input boundary conditions based on the real measurement and practical calculations of known MSW composition compared with other authors are used and the whole computational work is updated using real plant geometry and the appropriate turbulence, combustion and heat transfer models. Furthermore, the operating parameters were optimized on output parameters through a trade-off study. The different operating conditions were varied and the fluid flow direction, residence time, temperature field, velocity-field, nitric oxide formation and combustion products through the plant’s combustion chamber and preheat intersection in 3D were predicted and visualized. Optimization in real-time has showed the amounts for each input parameter when meeting the optimal operating conditions. Finally, the response charts between the input and output parameters are presented in order to monitor the dependence among these parameters. Further simulations have to be done to include the geometry dimensions as input parameters when applying the CDF simulation and numerical optimization within the project phase.

The Study of Waste-to-Energy Plant Combustion Characteristics Based on Computational Fluid Dynamics

2013 ◽  
Vol 871 ◽  
pp. 259-262
Author(s):  
Gui Chuan Hu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mass Fraction ◽  
Combustion Process ◽  
Waste To Energy ◽  
Pollutant Emissions ◽  
Plant Design ◽  
Detailed Understanding ◽  
Energy Plant ◽  
Proximate And Ultimate Analyses

The combustion process for using municipal solid waste as a fuel within a waste to energy plant calls for a detailed understanding of the following phenomena. Firstly, this process depends on many input parameters such as proximate and ultimate analyses, the season of the year, primary and secondary inlet air velocities and, secondly, on output parameters such as the temperatures or mass fraction of the combustible products. The variability and mutual dependence of these parameters can be difficult to manage in practice. Another problem is how these parameters can be tuned to achieving optimal combustible conditions with minimal pollutant emissions, during the plant-design phase. In order to meet these goals, a waste-to-energy plant with bed combustion was investigated by using computational fluid-dynamics approach.

Prediction of gaseous pollutant emissions from a spark-ignition direct-injection engine with gas-exchange simulation

2021 ◽  
pp. 146808742110050
Author(s):  
Stefania Esposito ◽  
Lutz Diekhoff ◽  
Stefan Pischinger
Keyword(s):  
Gas Exchange ◽  
Combustion Chamber ◽  
Direct Injection ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Operating Parameters ◽  
Gaseous Pollutant ◽  
Fuel Ratio ◽  
No Emissions

With the further tightening of emission regulations and the introduction of real driving emission tests (RDE), the simulative prediction of emissions is becoming increasingly important for the development of future low-emission internal combustion engines. In this context, gas-exchange simulation can be used as a powerful tool for the evaluation of new design concepts. However, the simplified description of the combustion chamber can make the prediction of complex in-cylinder phenomena like emission formation quite challenging. The present work focuses on the prediction of gaseous pollutants from a spark-ignition (SI) direct injection (DI) engine with 1D–0D gas-exchange simulations. The accuracy of the simulative prediction regarding gaseous pollutant emissions is assessed based on the comparison with measurement data obtained with a research single cylinder engine (SCE). Multiple variations of engine operating parameters – for example, load, speed, air-to-fuel ratio, valve timing – are taken into account to verify the predictivity of the simulation toward changing engine operating conditions. Regarding the unburned hydrocarbon (HC) emissions, phenomenological models are used to estimate the contribution of the piston top-land crevice as well as flame wall-quenching and oil-film fuel adsorption-desorption mechanisms. Regarding CO and NO emissions, multiple approaches to describe the burned zone kinetics in combination with a two-zone 0D combustion chamber model are evaluated. In particular, calculations with reduced reaction kinetics are compared with simplified kinetic descriptions. At engine warm operation, the HC models show an accuracy mainly within 20%. The predictions for the NO emissions follow the trend of the measurements with changing engine operating parameters and all modeled results are mainly within ±20%. Regarding CO emissions, the simplified kinetic models are not capable to predict CO at stoichiometric conditions with errors below 30%. With the usage of a reduced kinetic mechanism, a better prediction capability of CO at stoichiometric air-to-fuel ratio could be achieved.

scholarly journals Effect of Fuel and Air Dilution on Syngas Combustion in an Optical SI Engine

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1566 ◽  
Author(s):  
S.D. Martinez-Boggio ◽  
S.S. Merola ◽  
P. Teixeira Lacava ◽  
A. Irimescu ◽  
P.L. Curto-Risso
Keyword(s):  
Internal Combustion Engines ◽  
Combustion Process ◽  
Visible Spectrum ◽  
Propagation Speed ◽  
Fuel Mixture ◽  
Operating Conditions ◽  
Inert Gases ◽  
Pollutant Emissions ◽  
Si Engine ◽  
Lean Burn

To mitigate the increasing concentration of carbon dioxide in the atmosphere, energy production processes must change from fossil to renewable resources. Bioenergy utilization from agricultural residues can be a step towards achieving this goal. Syngas (fuel obtained from biomass gasification) has been proved to have the potential of replacing fossil fuels in stationary internal combustion engines (ICEs). The processes associated with switching from traditional fuels to alternatives have always led to intense research efforts in order to have a broad understanding of the behavior of the engine in all operating conditions. In particular, attention needs to be focused on fuels containing relatively high concentrations of hydrogen, due to its faster propagation speed with respect to traditional fossil energy sources. Therefore, a combustion study was performed in a research optical SI engine, for a comparison between a well-established fuel such as methane (the main component of natural gas) and syngas. The main goal of this work is to study the effect of inert gases in the fuel mixture and that of air dilution during lean fuelling. Thus, two pure syngas blends (mixtures of CO and H2) and their respective diluted mixtures (CO and H2 with 50vol% of inert gases, CO2 and N2) were tested in several air-fuel ratios (stoichiometric to lean burn conditions). Initially, the combustion process was studied in detail by traditional thermodynamic analysis and then optical diagnostics were applied thanks to the optical access through the piston crown. Specifically, images were taken in the UV-visible spectrum of the entire cycle to follow the propagation of the flame front. The results show that hydrogen promotes flame propagation and reduces its distortion, as well as resulting in flames evolving closer to the spark plug. All syngas blends show a stable combustion process, even in conditions of high air and fuel dilution. In the leanest case, real syngas mixtures present a decrease in terms of performance due to significant reduction in volumetric efficiency. However, this condition strongly decreases pollutant emissions, with nitrogen oxide (NOx) concentrations almost negligible.

scholarly journals Descriptive Statistical Analysis of Vegetable Oil Combustion in a Commercial Burner to Establish Optimal Operating Conditions

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2372 ◽  
Author(s):  
Julio San José ◽  
Yolanda Arroyo ◽  
María Ascensión Sanz-Tejedor
Keyword(s):  
Vegetable Oil ◽  
Combustion Process ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Airflow Rate ◽  
Optimal Operating ◽  
Combustion Performance ◽  
Fuel Flow ◽  
Oil Fuel ◽  
Descriptive Statistical Analysis

This article studies the combustion of refined sunflower, virgin sunflower and virgin rapeseed oils in a low-pressure auxiliary air fluid pulverization burner in order to establish the optimal operating conditions. The influence of varying the type of vegetable oil, fuel flow rate and secondary airflow rate in the combustion process was analyzed. These three factors are independent in the combustion process, which means having to carry out numerous assays, combining the various factors with one another. Given the amount of variables to be optimized and the existence of three factors, a statistical approach is adopted to help interpret the results obtained and to evaluate how each factor influences the combustion results. Optimal combustion is determined based on three criteria, minimum pollutant emissions (CO, NOx and CxHy), maximum combustion performance, and minimum excess air. The result of this study showed that airflow was the principal factor affecting emissions, whereas for combustion performance, both factors (airflow and fuel flow) were determinant. In general, admissible combustion performances were obtained, with CO and NOx emissions below permitted levels. The best combustion performance was achieved under conditions of maximum fuel flow and minimum airflow rates.

Numerical and Experimental Investigation on an Effusion-Cooled Lean Burn Aeronautical Combustor: Aerothermal Field and Emissions

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
L. Mazzei ◽  
S. Puggelli ◽  
D. Bertini ◽  
A. Andreini ◽  
B. Facchini ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Combustion Process ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Flame Spray ◽  
Distribution Factor ◽  
Lean Burn ◽  
Radial Temperature ◽  
Flamelet Generated Manifold ◽  
The Impact

Lean burn combustion is increasing its popularity in the aeronautical framework due to its potential in reducing drastically pollutant emissions (NOx and soot in particular). Its implementation, however, involves significant issues related to the increased amount of air dedicated to the combustion process, demanding the redesign of injection and cooling systems. Also, the conditions at the combustor exit are a concern, as high turbulence, residual swirl, and the impossibility to adjust the temperature profile with dilution holes determine a harsher environment for nozzle guide vanes. This work describes the final stages of the design of an aeronautical effusion-cooled lean burn combustor. Full annular tests were carried out to measure temperature profiles and emissions (CO and NOx) at the combustor exit. Different operating conditions of the ICAO cycle were tested, considering Idle, Cruise, Approach, and Take-off. Scale-adaptive simulations with the flamelet generated manifold (FGM) combustion model were performed to extend the validation of the employed computational fluid dynamics (CFD) methodology and to reproduce the experimental data in terms of radial temperature distribution factor (RTDF)/overall temperature distribution factor (OTDF) profiles as well as emission indexes (EIs). The satisfactory agreement paved the way to an exploitation of the methodology to provide a deeper understanding of the flow physics within the combustion chamber, highlighting the impact of the different operating conditions on flame, spray evolution, and pollutant formation.

Analysis of the Flame Structure in a Trapped Vortex Combustor Using Low and High-Speed OH-PLIF

2014 ◽  
Author(s):  
Pradip Xavier ◽  
Alexis Vandel ◽  
Gilles Godard ◽  
Bruno Renou ◽  
Frederic Grisch ◽  
...  
Keyword(s):  
High Speed ◽  
Laser Diagnostics ◽  
Flame Structure ◽  
Combustion Process ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Time Resolved ◽  
Lean Combustion ◽  
Stage Combustion ◽  
Trapped Vortex

Operating with lean combustion has led to more efficient “Low-NOx” burners but has also brought several technological issues. The burner design geometry is among the most important element as it controls, in a general way, the whole combustion process, the pollutant emissions and the flame stability. Investigation of new geometry concepts associating lean combustion is still under development, and new solutions have to meet the future pollutant regulations. This paper reports the experimental investigation of an innovative staged lean premixed burner. The retained annular geometry follows the Trapped Vortex Combustor concept (TVC) which operates with a two stage combustion chamber: a main lean flame (1) is stabilized by passing past a vortex shape rich-pilot flame (2) located within a cavity. This concept, presented in GT2012-68451 and GT2013-94704, seems to be promising but exhibits combustion instabilities in certain cases, then leading to undesirable level of pollutant emissions and could possibly conduct to serious material damages. No precise information have been reported in the literature about the chain of reasons leading to such an operation. The aim of this paper is to have insights about the main parameters controlling the combustion in this geometry. The flame structure dynamics is examined and compared for two specific operating conditions, producing an acoustically self-excited and a stable burner. Low and high-speed OH-PLIF laser diagnostics (up to 10 kHz) are used to have access to the flame curvature and to time-resolved events. Results show that the cavity jets location can lead to flow-field oscillations and a non-constant flame’s heat release. The associated flame structure, naturally influenced by turbulence is also affected by hot gases thermal expansion. Achieving a good and rapid mixing at the interface between the cavity and the main channel leads to a stable flame.

scholarly journals Tools for optimizing the operating conditions of waste-to-energy plant

2020 ◽  
Vol 61 (2) ◽  
pp. 97-103
Author(s):  
Vesna Alivojvodić ◽  
Marina Stamenović ◽  
Danijela Kovačević ◽  
Slaviša Putić
Keyword(s):  
Operating Conditions ◽  
Waste To Energy ◽  
Energy Plant

Numerical and Experimental Investigation on an Effusion-Cooled Lean Burn Aeronautical Combustor: Aerothermal Field and Emissions

2018 ◽  
Author(s):  
L. Mazzei ◽  
S. Puggelli ◽  
D. Bertini ◽  
A. Andreini ◽  
B. Facchini ◽  
...  
Keyword(s):  
Combustion Process ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Flame Spray ◽  
Lean Burn ◽  
Flamelet Generated Manifold ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes ◽  
The Impact

Lean burn combustion is increasing its popularity in the aeronautical framework due to its potential in reducing drastically pollutant emissions (NOx and soot in particular). Its implementation however involves significant issues related to the increased amount of air dedicated to the combustion process, demanding the redesign of injection and cooling systems. Also the conditions at the combustor exit are a concern, as high turbulence, residual swirl and the impossibility to adjust the temperature profile with dilution holes determine a harsher environment for nozzle guide vanes. This work describes the final stages of the design of an aeronautical effusion-cooled lean burn combustor. Full annular tests were carried out to measure temperature profiles and emissions (CO and NOx) at the combustor exit. Different operating conditions of the ICAO cycle were tested, considering Idle, Cruise, Approach and Take-Off. Scale-adaptive simulations with the Flamelet Generated Manifold combustion model were performed to extend the validation of the employed CFD methodology and to reproduce the experimental data in terms of RTDF/OTDF profiles as well as emission indexes. The satisfactory agreement paved the way to an exploitation of the methodology to provide a deeper understanding of the flow physics within the combustion chamber, highlighting the impact of the different operating conditions on flame, spray evolution and pollutant formation.

Variations in the Probe Beam Broadening with Operating Conditions in ESEM: Monte-Carlo Simulations and Edx Measurements

1997 ◽  
Vol 3 (S2) ◽  
pp. 1211-1212 ◽  
Author(s):  
I. C. Bache ◽  
S. Kitching ◽  
B. L. Thiel ◽  
A. M. Donald
Keyword(s):  
Probe Beam ◽  
Operating Conditions ◽  
Environmental Scanning ◽  
Operating Parameters ◽  
Critical Importance ◽  
X Ray ◽  
Computational Work ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Beam Broadening

An understanding of the scattering of an electron beam as it passes through a volume of low pressure gas is of critical importance for users of Low Vacuum and Environmental Scanning Electron Microscopes (LV-SEM & ESEM respectively) The ‘skirting’ of the primary beam as a result of scattering is of particular importance in X-ray microanalysis where scattered electrons, falling onto the sample away from the probe beam, can adversely affect the spatial resolution of the X-ray signal. A number of studies have attempted to quantify the width of the probe beam experimentally and hence determine optimum microscope operating parameters. Theoretical and computational work modelling the interactions of the beam with the gas have suggested that the shape of the probe beam can be modelled by some form of Gaussian. Experimental measurements, however, suggest that the probe has a skirted form rather than a Gaussian one.

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