scholarly journals Reduction of Major Pollutants via Air-staged Commbustion on Burner System

2013 ◽  
Vol 64 (1) ◽  
Author(s):  
Mohammad Nazri Mohd. Jaafar ◽  
Mohd Nur Hanafi Zaini
Keyword(s):  
Combustion Process ◽  
Primary Concern ◽  
Nox Emissions ◽  
Percent Reduction ◽  
Secondary Air ◽  
Secondary Zone ◽  
Combustion Processes ◽  
Different Gases ◽  
Air Staging ◽  
Co Emission

Emission from the combustion processes can cause adverse effect to the environment.  The formation of pollutants such as NOx, CO, CO2 and SOx are hazardous and harmful to the ecosystem.  The awareness about the pollution due to the combustion activities, particularly in industrial field has set off an effort to find more comprehensive and enhanced technologies to reduce these pollutants.  There are several methods that can be used to reduce the emissions of these pollutants either by combustion modifications or post combustion treatment.  In this research, the method used is the post combustion treatment, i.e. the air staging method.  By air staging techniques, some of the combustion air will be directed into the primary combustion zone, while the remaining air is directed into the secondary zone.  The function of the secondary air is to reduce the peak flame temperatures, which theoretically reduce the emissions of NOx emissions.  The primary concern for this research is to study the effectiveness of the air staging in reducing NOx, CO, SO2, and UHC emissions from the combustion process.  The results obtained showed significant reduction in all major pollutants, i.e., a 31.8 percent reduction for CO emission, 16.8 percent for NOx, 12.7 percent for SO2 and 10.3 percent for UHC.  These reductions were obtained at different equivalence ratios for different gases.

scholarly journals Investigations of combustion process in combined cooker-boiler fired on solid fuels

2006 ◽  
Vol 10 (4) ◽  
pp. 121-130
Author(s):  
Dragoslava Stojiljkovic ◽  
Vladimir Jovanovic ◽  
Milan Radovanovic ◽  
Nebojsa Manic ◽  
Ivo Radulovic
Keyword(s):  
Flue Gas ◽  
Combustion Process ◽  
Solid Fuels ◽  
Gas Temperature ◽  
Weight Changes ◽  
Complete Combustion ◽  
Air Supply ◽  
Class 1 ◽  
Secondary Air ◽  
Co Emission

The aim of the investigation was to make some reconstructions on the existing stove used for cooking and baking and to obtain the combined cooker-boiler which will fulfill the demands of European standard EN 12815. Implementation of modern scientific achievements in the field of combustion on stoves and furnaces fired on solid fuels was used. During the investigations four various constructions were made with different fresh air inlet and secondary air supply with the intention to obtain more complete combustion with increased efficiency and reduced CO emission. Three different fuels were used: firewood, coal, and wood briquette. A numerous parameters were measured: fuel weight changes during the combustion process, temperature of inlet and outlet water, flue gas composition (O2, CO, SO2, CO2, NOx), flue gas temperature, ash quantity etc. The result of the investigations is the stove with the efficiency of more than 75% - boiler Class 1 (according EN 12815) and CO emission of about 1% v/v. The results obtained during the measurements were used as parameters for modeling of combustion process. .

A Study on Biodiesel NOx Emission Control With the Reduced Chemical Kinetics Model

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Juncheng Li ◽  
Zhiyu Han ◽  
Cai Shen ◽  
Chia-fon Lee
Keyword(s):  
Chemical Kinetics ◽  
Combustion Process ◽  
Operating Conditions ◽  
Nox Emission ◽  
Kinetics Model ◽  
Combustion Model ◽  
Nox Emissions ◽  
Soot Emission ◽  
Start Of Injection ◽  
Combustion Processes

In this paper, the effects of the start of injection (SOI) timing and exhaust gas recirculation (EGR) rate on the nitrogen oxides (NOx) emissions of a biodiesel-powered diesel engine are studied with computational fluid dynamics (CFD) coupling with a chemical kinetics model. The KIVA code coupling with a CHEMKIN-II chemistry solver is applied to the simulation of the in-cylinder combustion process. A surrogate biodiesel mechanism consisting of two fuel components is employed as the combustion model of soybean biodiesel. The in-cylinder combustion processes of the cases with four injection timings and three EGR rates are simulated. The simulation results show that the calculated NOx emissions of the cases with default EGR rate are reduced by 20.3% and 32.9% when the injection timings are delayed by 2- and 4-deg crank angle, respectively. The calculated NOx emissions of the cases with 24.0% and 28.0% EGR are reduced by 38.4% and 62.8%, respectively, compared to that of the case with default SOI and 19.2% EGR. But higher EGR rate deteriorates the soot emission. When EGR rate is 28.0% and SOI is advanced by 2 deg, the NOx emission is reduced by 55.1% and soot emission is controlled as that of the case with 24% EGR and default SOI. The NOx emissions of biodiesel combustion can be effectively improved by SOI retardation or increasing EGR rate. Under the studied engine operating conditions, introducing more 4.8% EGR into the intake air with unchanged SOI is more effective for NOx emission controlling than that of 4-deg SOI retardation with default EGR rate.

scholarly journals The Optimization And Diagnostics Of Combustion Process With Numerical Modelling Application

2015 ◽  
Vol 60 (2) ◽  
pp. 687-695
Author(s):  
M. Zajemska ◽  
H. Radomiak ◽  
A. Poskart
Keyword(s):  
Numerical Modelling ◽  
Gas Flow ◽  
Research Work ◽  
Combustion Process ◽  
Experimental Chamber ◽  
Hot Air ◽  
Real Objects ◽  
Fluent Software ◽  
Secondary Air ◽  
Combustion Processes

Abstract The progressing development of industry and the associated rising environmental pollution create the need for the intensification of combustion processes and the implementation of increasingly stringent environmental protection standards. Therefore, an intensive progress in scientific and research work that is lately observed and studies with the use of numerical methods, are becoming an indispensable element of experimental research. This allows for: optimization of combustion processes, development of new designs of burners and technologies of low-emission combustion, as well as prediction of ecological effects. This article presents the possibilities of numerical modelling in combustion processes in heat furnaces. The chemistry of the combustion process was modelled in CHEMKIN software, while the dynamics of flue gas flow in the combustion chamber was modelled with the use of FLUENT software. Numerical computations were performed for both, the experimental chamber and the real objects, i.e. a pusher furnace and a sheet hardening furnace. The results of obtained measurements and numerical calculations clearly show that the use of hot air affects the growth of emissions, in particular NOx. Furthermore, it has also been proved that the design and the appropriate location of the lance supplying the secondary air result in the reduction of emissions of nitrogen oxides.

Comparison of NOx Emissions Decreasing Methods for Biofuel Boilers

2017 ◽  
Author(s):  
Titas Sereika ◽  
Kęstutis Buinevičius ◽  
Adolfas Jančauskas
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Main Idea ◽  
Nox Emissions ◽  
Reduction Methods ◽  
Reduction Of Nox ◽  
Secondary Air ◽  
Nitrogen Oxides Reduction ◽  
Gas Recirculation ◽  
Co Emission

The main idea of research is to figure out the emissions of nitrogen oxides reduction using various type of reduction methods. In experiments were used NOx reduction methods: high CO emissions generation, flue gas recirculation, water and water vapor supply, selective non-catalytic reduction (SNCR), and SNCR with flammable additive. This study presents emission and combustion results obtained burning furniture production waste which generates higher rate of NOx emissions. The result of research shows, that CO emission has the biggest impact factor -on reducing NOx emission. Burning fuel in combustion zone with first and secondary air ratio (40/60) and using methods for higher generation CO emissions reached 3.000 mg/m3 which reduces NOx emissions up to 83%. Using selective non-catalytic reduction with traditional and flammable additives reduction of NOx emissions reached up to 55%.

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.

scholarly journals Comprehensive Thermodynamic Analysis of the Humphrey Cycle for Gas Turbines with Pressure Gain Combustion

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3521 ◽  
Author(s):  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Ideal Gas ◽  
Point Of View ◽  
Pressure Gain Combustion ◽  
Combustion Technology ◽  
Secondary Air ◽  
And Performance ◽  
The Impact

Conventional gas turbines are approaching their efficiency limits and performance gains are becoming increasingly difficult to achieve. Pressure Gain Combustion (PGC) has emerged as a very promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine thermodynamic cycles. Up to date, only very simplified models of open cycle gas turbines with pressure gain combustion have been considered. However, the integration of a fundamentally different combustion technology will be inherently connected with additional losses. Entropy generation in the combustion process, combustor inlet pressure loss (a central issue for pressure gain combustors), and the impact of PGC on the secondary air system (especially blade cooling) are all very important parameters that have been neglected. The current work uses the Humphrey cycle in an attempt to address all these issues in order to provide gas turbine component designers with benchmark efficiency values for individual components of gas turbines with PGC. The analysis concludes with some recommendations for the best strategy to integrate turbine expanders with PGC combustors. This is done from a purely thermodynamic point of view, again with the goal to deliver design benchmark values for a more realistic interpretation of the cycle.

scholarly journals Effects of Catalysts on Emissions of Pollutants from Combustion Processes of Liquid Fuels

2014 ◽  
Vol 13 (2) ◽  
pp. 5-17
Author(s):  
Agnieszka Bok ◽  
Joanna Guziałowska-Tic ◽  
Wilhelm Jan Tic
Keyword(s):  
Combustion Process ◽  
Combustion Products ◽  
Organometallic Complexes ◽  
Liquid Fuels ◽  
Motor Fuels ◽  
Harmful Emissions ◽  
Fuel Oils ◽  
Sulphur Oxides ◽  
Dynamic Growth ◽  
Combustion Processes

Abstract The dynamic growth of the use of non-renewable fuels for energy purposes results in demand for catalysts to improve their combustion process. The paper describes catalysts used mainly in the processes of combustion of motor fuels and fuel oils. These catalysts make it possible to raise the efficiency of oxidation processes simultanously reducing the emission of pollutants. The key to success is the selection of catalyst compounds that will reduce harmful emissions of combustion products into the atmosphere. Catalysts are introduced into the combustion zone in form of solutions miscible with fuel or with air supplied to the combustion process. The following compounds soluble in fuel are inclused in the composition of the described catalysts: organometallic complexes, manganese compounds, salts originated from organic acids, ferrocen and its derivatives and sodium chloride and magnesium chloride responsible for burning the soot (chlorides). The priority is to minimize emissions of volatile organic compounds, nitrogen oxides, sulphur oxides, and carbon monoxide, as well as particulate matter.

Comparison of Numerical Combustion Models for Hydrogen and Hydrogen-Rich Syngas Applied for Dry-Low-NOx-Micromix-Combustion

2016 ◽  
Author(s):  
H. H.-W. Funke ◽  
N. Beckmann ◽  
J. Keinz ◽  
S. Abanteriba
Keyword(s):  
Reaction Mechanism ◽  
Gas Turbines ◽  
Combustion Process ◽  
Computational Effort ◽  
Hydrogen Combustion ◽  
Combustion Stability ◽  
Research Approach ◽  
Pure Hydrogen ◽  
Nox Emissions ◽  
Combustion Models

The Dry-Low-NOx (DLN) Micromix combustion technology has been developed as low emission combustion principle for industrial gas turbines fueled with hydrogen or syngas. The combustion process is based on the phenomenon of jet-in-crossflow-mixing. Fuel is injected perpendicular into the air-cross-flow and burned in a multitude of miniaturized, diffusion-like flames. The miniaturization of the flames leads to a significant reduction of NOx emissions due to the very short residence time of reactants in the flame. In the Micromix research approach, CFD analyses are validated towards experimental results. The combination of numerical and experimental methods allows an efficient design and optimization of DLN Micromix combustors concerning combustion stability and low NOx emissions. The paper presents a comparison of several numerical combustion models for hydrogen and hydrogen-rich syngas. They differ in the complexity of the underlying reaction mechanism and the associated computational effort. For pure hydrogen combustion a one-step global reaction is applied using a hybrid Eddy-Break-up model that incorporates finite rate kinetics. The model is evaluated and compared to a detailed hydrogen combustion mechanism derived by Li et al. including 9 species and 19 reversible elementary reactions. Based on this mechanism, reduction of the computational effort is achieved by applying the Flamelet Generated Manifolds (FGM) method while the accuracy of the detailed reaction scheme is maintained. For hydrogen-rich syngas combustion (H2-CO) numerical analyses based on a skeletal H2/CO reaction mechanism derived by Hawkes et al. and a detailed reaction mechanism provided by Ranzi et al. are performed. The comparison between combustion models and the validation of numerical results is based on exhaust gas compositions available from experimental investigation on DLN Micromix combustors. The conducted evaluation confirms that the applied detailed combustion mechanisms are able to predict the general physics of the DLN-Micromix combustion process accurately. The Flamelet Generated Manifolds method proved to be generally suitable to reduce the computational effort while maintaining the accuracy of detailed chemistry. Especially for reaction mechanisms with a high number of species accuracy and computational effort can be balanced using the FGM model.

Mechanisms and kinetics of initial pyrolysis and combustion reactions of 1,1-diamino-2,2-dinitroethylene from density functional tight-binding molecular dynamics simulations

2019 ◽  
Vol 97 (11) ◽  
pp. 795-804 ◽  
Author(s):  
Dong Xiang ◽  
Weihua Zhu
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Density Functional ◽  
Tight Binding ◽  
Combustion Process ◽  
Exponential Factor ◽  
Three Stages ◽  
Dynamics Simulations ◽  
Combustion Processes ◽  
Kinetics Of

The density functional tight-binding molecular dynamics approach was used to study the mechanisms and kinetics of initial pyrolysis and combustion reactions of isolated and multi-molecular FOX-7. Based on the thermal cleavage of bridge bonds, the pyrolysis process of FOX-7 can be divided into three stages. However, the combustion process can be divided into five decomposition stages, which is much more complex than the pyrolysis reactions. The vibrations in the mean temperature contain nodes signifying the formation of new products and thereby the transitions between the various stages in the pyrolysis and combustion processes. Activation energy and pre-exponential factor for the pyrolysis and combustion reactions of FOX-7 were obtained from the kinetic analysis. It is found that the activation energy of its pyrolysis and combustion reactions are very low, making both take place fast. Our simulations provide the first atomic-level look at the full dynamics of the complicated pyrolysis and combustion process of FOX-7.

scholarly journals Reduction of Unburned Carbon Release and NOx Emission from a Pulverized Wood Pellet Boiler Retrofitted for Fuel Switching from Coal

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5077 ◽  
Author(s):  
Jiseok Lee ◽  
Seunghan Yu ◽  
Jinje Park ◽  
Hyunbin Jo ◽  
Jongkeun Park ◽  
...  
Keyword(s):  
Power Plant ◽  
Bottom Ash ◽  
Flow Characteristics ◽  
Electricity Production ◽  
Unburned Carbon ◽  
Nox Emissions ◽  
Wood Pellet ◽  
Operating Variables ◽  
Carbon Release ◽  
Air Staging

For renewable electricity production, biomass can fully displace coal in an existing power plant with some equipment modifications. Recently, a 125 MWe power plant burning mainly anthracite in Korea was retrofitted for dedicated wood pellet combustion with a change of boiler configuration from arch firing to wall firing. However, this boiler suffers from operational problems caused by high unburned carbon (UBC) contents in the bottom ash. This study comprises an investigation of some methods to reduce the UBC release while achieving lower NOx emissions. The computational fluid dynamics approach was established and validated for typical operating data. Subsequently, it was applied to elucidate the particle combustion and flow characteristics leading to the high UBC content and to evaluate the operating variables for improving the boiler performance. It was found that the high UBC content in the bottom ash was a combined effect of the poor fuel grindability and low gas velocity in the wide burner zone originating from the arch-firing boiler. This prevented the operation with deeper air staging for lower NOx emissions. Reducing the particle size to <1.5 mm by modifying mills or pretreating the fuel using torrefaction was the only effective way of lowering the UBC and NOx emissions with deeper air staging while increasing the boiler efficiency.

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