Reduction of Pollutants Emissions From Domestic Boilers: CFD Study

2008 ◽  
Author(s):  
Gasser Hassan ◽  
Mohamed Pourkashanian ◽  
Derek Ingham ◽  
Lin Ma ◽  
Stephen Taylor
Keyword(s):  
Combustion Chamber ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Cfd Model ◽  
Inlet Velocity ◽  
Average Temperature ◽  
Partially Premixed Combustion ◽  
Boiler Efficiency ◽  
Computational Fluid Dynamics Cfd

This study is concerned with building a computational fluid dynamics (CFD) model to simulate the combustion process occurring in the combustion chamber of some domestic boilers. The burner used in this boiler is a conventional cylindrical premix burner with small inlet holes on its surface. A two-dimensional (2D) CFD model is built to simulate the combustion chamber domain and the partially premixed combustion model with a postprocessor for NOx calculations is used to simulate the combustion process inside the combustion chamber. A complete description of the formation characteristics of NOx produced from the boiler is discussed in detail. A comparison between the CFD numerical results and the experimental measurements at different boiler loads is performed in order to validate the numerical model and investigate the accuracy of the CFD model. The validated CFD model is used to investigate the effect of different boundaries temperatures and the mixture inlet velocity on the flue gas average temperature, residence time and hence the CO and NOx concentrations produced from the combustion chamber. The concept of changing the mixture inlet velocity is found to be an effective method to improve the design of the burner in order to reduce the pollutant emissions produced from the boiler with no effect on the boiler efficiency.

Reduction in Pollutants Emissions From Domestic Boilers—Computational Fluid Dynamics Study

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Gasser Hassan ◽  
Mohamed Pourkashanian ◽  
Derek Ingham ◽  
Lin Ma ◽  
Stephen Taylor
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Combustion Chamber ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Cfd Model ◽  
Inlet Velocity ◽  
Average Temperature ◽  
Partially Premixed Combustion

This study is concerned with building a computational fluid dynamics (CFD) model to simulate the combustion process occurring in the combustion chamber of some domestic boilers. The burner used in this boiler is a conventional cylindrical premix burner with small inlet holes on its surface. A two-dimensional CFD model is built to simulate the combustion chamber domain, and the partially premixed combustion model with a postprocessor for NOx calculations is used to simulate the combustion process inside the combustion chamber. A complete description of the formation characteristics of NOx produced from the boiler is discussed in detail. A comparison between the CFD numerical results and the experimental measurements at different boiler loads is performed in order to validate the numerical model and investigate the accuracy of the CFD model. The validated CFD model is used to investigate the effect of different boundaries temperatures and the mixture inlet velocity on the flue gas average temperature, residence time, and hence the CO and NOx concentrations produced from the combustion chamber. The concept of changing the mixture inlet velocity is found to be an effective method to improve the design of the burner in order to reduce the pollutant emissions produced from the boiler with no effect on the boiler efficiency.

Study of Combustion Instabilities Imposed by Inlet Velocity Disturbance in Combustor Using LES

2009 ◽  
Author(s):  
Kenji Sato ◽  
Ed Knudsen ◽  
Heinz Pitsch
Keyword(s):  
Transfer Function ◽  
Flow Field ◽  
Heat Release ◽  
Combustion Chamber ◽  
Combustion Process ◽  
Variable Density ◽  
Combustion Model ◽  
Combustion Instabilities ◽  
Inlet Velocity ◽  
Good Agreement

Stable combustion is one of the most important requirements for the development of heavy duty gas turbine engines that comply with stringent environmental regulations at high firing temperatures. In this research, one of the typical combustion instabilities which is caused by an acoustically forced velocity disturbance is investigated using variable density LES simulations. The G-equation approach for LES is used as the combustion model [1], and an experiment by Balachandran et al. [2, 3] is selected for case study. The velocity profiles in the experimental combustion chamber are compared with experimentally measured data at non-reacting conditions and it is confirmed that these are in good agreement. At the reacting conditions, predicted flame shapes are compared with OH PLIF measurements. The transfer function of the heat release due to inlet velocity forcing at 40 Hz and 160 Hz frequencies is also compared with the experimental data. These are in good agreement, including the nonlinear response of heat release. The transfer function is highly related to the flow field. The non-linearity of the transfer function can be traced to the interaction of the flow field in the combustion chamber with the combustion process itself.

scholarly journals Combustion Optimization for Coal Fired Power Plant Boilers Based on Improved Distributed ELM and Distributed PSO

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1036 ◽  
Author(s):  
Xinying Xu ◽  
Qi Chen ◽  
Mifeng Ren ◽  
Lan Cheng ◽  
Jun Xie
Keyword(s):  
Power Plant ◽  
Combustion Process ◽  
Optimization Method ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Nox Emissions ◽  
Coupling Characteristics ◽  
Learning Machine ◽  
Combustion Optimization

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.

Prediction of Pressure Rise in a Gas Turbine Exhaust Duct Under Flameout Scenarios While Operating On Hydrogen and Natural Gas Blends

2021 ◽  
Author(s):  
Orlando Ugarte ◽  
Suresh Menon ◽  
Wayne Rattigan ◽  
Paul Winstanley ◽  
Priyank Saxena ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Combustion Model ◽  
Computational Domain ◽  
Cfd Model ◽  
Exhaust Duct ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Abstract In recent years, there is a growing interest in blending hydrogen with natural gas fuels to produce low carbon electricity. It is important to evaluate the safety of gas turbine packages under these conditions, such as late-light off and flameout scenarios. However, the assessment of the safety risks by performing experiments in full-scale exhaust ducts is a very expensive and, potentially, risky endeavor. Computational simulations using a high fidelity CFD model provide a cost-effective way of assessing the safety risk. In this study, a computational model is implemented to perform three dimensional, compressible and unsteady simulations of reacting flows in a gas turbine exhaust duct. Computational results were validated against data obtained at the simulated conditions in a representative geometry. Due to the enormous size of the geometry, special attention was given to the discretization of the computational domain and the combustion model. Results show that CFD model predicts main features of the pressure rise driven by the combustion process. The peak pressures obtained computationally and experimentally differed in 20%. This difference increased up to 45% by reducing the preheated inflow conditions. The effects of rig geometry and flow conditions on the accuracy of the CFD model are discussed.

Phenomenological Modeling of Combustion in Pre-Chamber and the Pilot Flame for Natural Gas Engines

2019 ◽  
Author(s):  
Long Liu ◽  
Xia Wen ◽  
Qian Xiong ◽  
Xiuzhen Ma
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Alternative Fuels ◽  
Gas Flow ◽  
Combustion Process ◽  
Clean Energy ◽  
Combustion Model ◽  
Flame Surface ◽  
Flow Process ◽  
Natural Gas Engines

Abstract With energy shortages and increasing environmental problems, natural gas, as a clean energy, has the advantages of cheap price and large reserves and has become one of the main alternative fuels for marine diesel engines. For large bore natural gas engines, pre-chamber spark plug ignition can be used to increase engine efficiency. The engine mainly relies on the flame ejected from the pre-chamber to ignite the mixture of natural gas and air in the main combustion chamber. The ignition flame in the main combustion chamber is the main factor affecting the combustion process. Although the pre-chamber natural gas engines have been extensively studied, the characteristics of combustion in the pre-chamber and the development of ignition flame in the main combustion chamber have not been fully understood. In this study, a two-zone phenomenological combustion model of pre-chamber spark-ignition natural gas engines is established based on the exchange of mass and energy of the gas flow process in the pre-chamber and the main combustion chamber. The basic characteristics of the developed model are: a spherical flame surface is used to describe the combustion state in the pre-chamber, and according to the turbulent jet theory, the influence of turbulence on the state of the pilot flame is considered based on the Reynolds number. According to the phenomenological model, the time when the flame starts to be injected from the pre-chamber to the main combustion chamber, and the parameters such as the length of the pilot flame are analyzed. The model was verified by experimental data, and the results showed that the calculated values were in good agreement with the experimental values. It provides an effective tool for mastering the law of flame development and supporting the optimization of combustion efficiency.

A Control-Oriented Jet Ignition Combustion Model for an SI Engine

2015 ◽  
Author(s):  
Ruitao Song ◽  
Gerald Gentz ◽  
Guoming Zhu ◽  
Elisa Toulson ◽  
Harold Schock
Keyword(s):  
Combustion Chamber ◽  
Combustion Process ◽  
Turbulent Jets ◽  
Combustion Stability ◽  
Combustion Model ◽  
Combustion Chambers ◽  
Si Engine ◽  
Lean Operations ◽  
Combustion Processes ◽  
Hil Simulation

A turbulent jet ignition system of a spark ignited (SI) engine consists of pre-combustion and main-combustion chambers, where the combustion in the main-combustion chamber is initiated by turbulent jets of reacting products from the pre-combustion chamber. If the gas exchange and combustion processes are accurately controlled, the highly distributed ignition will enable very fast combustion and improve combustion stability under lean operations, which leads to high thermal efficiency, knock limit extension, and near zero NOx emissions. For model-based control, a precise combustion model is a necessity. This paper presents a control-oriented jet ignition combustion model, which is developed based on simplified fluid dynamics and thermodynamics, and implemented into a dSPACE based real-time hardware-in-the-loop (HIL) simulation environment. The two-zone combustion model is developed to simulate the combustion process in two combustion chambers. Correspondingly, the gas flowing through the orifices between two combustion chambers is divided into burned and unburned gases during the combustion process. The pressure traces measured from a rapid compression machine (RCM), equipped with a jet igniter, are used for initial model validation. The HIL simulation results show a good agreement with the experimental data.

Prediction of Pressure Rise in a Gas Turbine Exhaust Duct Under Flameout Scenarios While Operating on Hydrogen and Natural Gas Blends

2021 ◽  
Author(s):  
Orlando Ugarte ◽  
Suresh Menon ◽  
Wayne Rattigan ◽  
Paul Winstanley ◽  
Priyank Saxena ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Combustion Model ◽  
Computational Domain ◽  
Cfd Model ◽  
Exhaust Duct ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Abstract In recent years, there is a growing interest in blending hydrogen with natural gas fuels to produce low carbon electricity. It is important to evaluate the safety of gas turbine packages under these conditions, such as late-light off and flameout scenarios. However, the assessment of the safety risks by performing experiments in full-scale exhaust ducts is a very expensive and, potentially, risky endeavor. Computational simulations using a high fidelity CFD model provide a cost-effective way of assessing the safety risk. In this study, a computational model is implemented to perform three dimensional, compressible and unsteady simulations of reacting flows in a gas turbine exhaust duct. Computational results were validated against data obtained at the simulated conditions in a representative geometry. Due to the enormous size of the geometry, special attention was given to the discretization of the computational domain and the combustion model. Results show that CFD model predicts main features of the pressure rise driven by the combustion process. The peak pressures obtained computationally and experimentally differed in 20%. This difference increased up to 45% by reducing the preheated inflow conditions. The effects of rig geometry and flow conditions on the accuracy of the CFD model are discussed.

Analysis of a HSDI Diesel Engine Intake System by Means of Multi-Dimensional Numerical Simulations: Influence of Non Uniform EGR Distribution

2006 ◽  
Author(s):  
Giuseppe Cantore ◽  
Carlo Arturo De Marco ◽  
Luca Montorsi ◽  
Fabrizio Paltrinieri ◽  
Carlo Alberto Rinaldini
Keyword(s):  
Diesel Engine ◽  
Numerical Simulations ◽  
Mutual Influence ◽  
Combustion Process ◽  
Engine Performance ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
3D Analysis ◽  
Intake System ◽  
Hsdi Diesel Engine

In order to comply with stringent pollutant emissions regulations a detailed analysis of the overall engine is required, assessing the mutual influence of its main operating parameters. The present study is focused on the investigation of the intake system under actual working conditions by means of 1D and 3D numerical simulations. Particularly, the effect of EGR distribution on engine performance and pollutants formation has been calculated for a production 6 cylinder HSDI Diesel engine in a EUDC operating point. Firstly a coupled 1D/3D simulation of the entire engine geometry has been carried out to estimate the EGR rate delivered to every cylinder; subsequently the in-cylinder flow field has been evaluated by simulating the intake and compression strokes. Finally the spray and combustion processes have been studied accounting for the real combustion chamber geometry and particularly the pollutants formation has been determined by using a detailed kinetic mechanism combustion model. The 1D/3D analysis highlighted a significant cylinder to cylinder EGR percentage variation affecting remarkably the pollutant emissions formation, as evaluated by the combustion process simulations. A combined use of commercial and in-house modified codes has been adopted.

scholarly journals Numerical Simulation of the Combustion Chamber for a New Reference Combustion Calorimeter

2019 ◽  
pp. 12-20
Author(s):  
Eli González-Durán ◽  
Marco Zamora-Antuñano ◽  
Leonel Lira-Cortes ◽  
Nestor Méndez-Lozano
Keyword(s):  
Combustion Chamber ◽  
Surrounding Medium ◽  
Combustion Process ◽  
Calorific Value ◽  
Transient State ◽  
Cylindrical Body ◽  
Combustion Gases ◽  
Dissipation Model ◽  
Computational Fluid Dynamics Cfd ◽  
Combustion Calorimeter

The Centro Nacional de Metrología is developing a reference calorimeter to measure the superior calorific value of natural gas in collaboration with the Instituto Tecnológico de Celaya. We present the study of the combustion chamber for two formulations a steady state (already published) against the transient state. The study of the combustion chamber is performed employing computational fluid dynamics (CFD) through FLUENT®. For this work, specific parameters were set to define and simulate the combustion process involving the exchange of energy, momentum and mass transfer. In this work, we present simulations performed in steady and transient state, for which was used the Eddy Dissipation Model (EDM). Is shown the simulation of two geometries for the combustion chamber; one cylindrical body a hemispherical lid and the other elliptical, which was proposed to increase the area to heat transfer to the surrounding medium, water in our case. The criterion for selection is the chamber that achieves the lowest temperature for waste combustion gases at the exit. Achieved by the cylindrical chamber with a hemispherical lid in the first 4 seconds with a difference of 0.4 °C lower than the elliptical chamber.

CFD Simulation of a Microturbine Annular Combustion Chamber Fuelled With Methane and Biomass Pyrolysis Syngas: Preliminary Results

2009 ◽  
Author(s):  
Francesco Fantozzi ◽  
Paolo Laranci ◽  
Michele Bianchi ◽  
Andrea De Pascale ◽  
Michele Pinelli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Calorific Value ◽  
Methane Combustion ◽  
Pollutant Emissions ◽  
Preliminary Results

Micro gas turbines could be profitably used, for distributed energy production, also exploiting low calorific value biomass-derived fuels, obtained by means of integrated pyrolysis and/or gasification processes. These synthesis gases show significant differences with respect to natural gas (in terms of composition, low calorific value, hydrogen content, tar and particulate matter content) that may turn into ignition problems, combustion instabilities, difficulties in emission control and fouling. CFD simulation of the combustion chamber is a key instrument to identify main criticalities arising when using these gases, in order to modify existing geometries and to develop new generation combustion chambers for use with low calorific value gases. This paper describes the numerical activity carried out to analyze the combustion process occurring inside an existing microturbine annular combustor. A CFD study of the combustion process performed with different computational codes is introduced and some preliminary results are reported in the paper. A comparison of results obtained with the different codes is provided, for the reference case of methane combustion. A first evaluation of the pollutant emissions and a comparison with the available experimental data is also provided in the paper, showing in particular a good matching of experimental data on NOx emissions at different load conditions. Moreover, the carried out investigation concerns the case of operation with a syngas fuel derived from pyrolysis of biomass and finally the case of syngas and natural gas co-firing. This combustion condition is simulated with a simple reduced chemical kinetic scheme, in order to assess only the key issues rising with this fuel in comparison with the case of methane combustion. The analysis shows that in case of syngas operation the combustor internal temperature hot spots are reduced and the primary zone flame tends to stabilize closer to the injector, with possible implications on the emission release.

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