Simulation of Circulating Fluidized Bed (CFB) Boiler Oxygen-Enriched Combustion

2012 ◽  
Vol 614-615 ◽  
pp. 139-142
Author(s):  
Yuan Ping Xu ◽  
Hua Zhou ◽  
Qing Yin Jiang
Keyword(s):  
Oxygen Content ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Configuration Software ◽  
Combustion Model ◽  
Cfb Boiler ◽  
Industrial Data ◽  
Real Process ◽  
The Relationship

In this paper, we focus on the relationship between oxygen-enriched combustion efficiency and oxygen content of primary air under N2 /O2 atmosphere combustion on CFB boiler. Firstly, an entirely possible of CFB boiler oxygen-enriched combustion model was proposed. Secondly, a platform was built for simulation of CFB combustion process on XD-APC configuration software. Finally, industrial simulation with industrial data was going on to prove the platform was reasonable. The simulation results were consistent of industrial data. It shows the simulation platform reliability, and the model accuracy. On this basis, coal combustion efficiency was simulated. It shows that the combustion efficiency increases following by oxygen content increasing. It’s economic for real process when oxygen content chooses from 25% to 30%.

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 Specific Features of Solid Fuels Combustion in Oxygen Atmosphere with Recirculation of CO2

2015 ◽  
Vol 17 (3) ◽  
pp. 213
Author(s):  
D.A. Melnikov ◽  
G.A. Ryabov
Keyword(s):  
Coal Combustion ◽  
Carbon Capture ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Carbon Capture And Storage ◽  
Combustion Model ◽  
Coal Pyrolysis ◽  
Char Particle ◽  
Isothermal Kinetic ◽  
Gasification Reaction

<p>Aspects of coal combustion have been experimentally studied under oxyfuel conditions, one of the promising technologies for carbon capture and storage (CCS). Here, the thermogravimetric analysis (TGA) method was chosen as an experimental technique. Coal pyrolysis tests performed under an O<sub>2</sub>/CO<sub>2</sub> atmosphere were compared with a conventional O<sub>2</sub>/N<sub>2</sub> environment in terms of reaction rate and total volatile yield. Combustion of the resulting chars in the corresponding atmospheres revealed somewhat different combustion rates with a less vigorous reaction in the O<sub>2</sub>/CO<sub>2</sub> medium. The two manipulated factors – namely, the inherently different char reactivities due to the different atmospheres they were obtained in and the different atmospheres of the actual combustion process – were distinguished by performing another series of tests with chars pyrolysed under identical conditions using a standard routine. These chars also showed a weaker reaction in O<sub>2</sub>/CO<sub>2</sub> atmosphere, which was attributed to the lower binary diffusion coefficient of the O<sub>2</sub>/CO<sub>2</sub> pair. The activity of the char – CO<sub>2 </sub>gasification reaction in an O<sub>2</sub>/CO<sub>2</sub> environment was also investigated and revealed some contribution of this reaction to the conversion process. This was particularly noticeable at temperatures above 750 °C and under an internal diffusional controlled regime (zone II), implying displacement of oxygen out of the char particle pore volume, which allowed free reaction of CO<sub>2</sub> on the developed pore surface. Non-isothermal kinetic analysis of the intrinsic kinetics of the oxidation reaction in O<sub>2</sub>/CO<sub>2</sub> revealed no particular difference compared to the O<sub>2</sub>/N<sub>2</sub> medium, at least when the char-CO<sub>2 </sub>reaction was inhibited. The obtained data were used to develop a coal combustion model under O<sub>2</sub>/CO<sub>2</sub> conditions, which was then incorporated as a combustion module into circulating fluidized bed (CFB) computation software.</p>

Investigation on Reaction Flow Field of Low Emission TAPS Combustors

2014 ◽  
Vol 694 ◽  
pp. 45-48
Author(s):  
Qun Zhang ◽  
Hua Sheng Xu ◽  
Tao Gui ◽  
Shun Li Sun ◽  
Yue Wu ◽  
...  
Keyword(s):  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Model ◽  
Outlet Temperature ◽  
Gas Temperature ◽  
Distribution Factor ◽  
Two Phase ◽  
Nox Formation ◽  
Low Emission ◽  
Thermal Nox

A twin annular premixing swirler (TAPS) combustor model of low emissions was developed in this study. And computational studies on combustion process in the combustor model were carried out. Standard k-ε Turbulence Model, PDF non-premixed combustion model, Zeldovich thermal NOx formation model and DPM two-phase model were employed. The distributions of some key performance parameters such as gas temperature, flow velocity, concentrations of NOx and CO emissions were obtained and analyzed. At the same time, combustion mechanics inside the TAPS combustor model were investigated. The computational results indicated that the TAPS combustor employed in this study does a better job of improving key combustion performances such as combustion efficiency, total pressure recovery and outlet temperature distribution factor, and reducing NOx and CO emissions at the same time.

scholarly journals Interactive graph dynamics for fuzzy autocatalytic set of fuzzy graph of type-3 for combustion process in a circulating fluidized bed boiler

2015 ◽  
Vol 11 (1) ◽  
Author(s):  
Hazwani Hashim ◽  
Sumarni Abu Bakar
Keyword(s):  
Fluidized Bed ◽  
Chemical Reactions ◽  
Transition Matrix ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Fuzzy Graph ◽  
The Real ◽  
Real Process ◽  
Graph Dynamics ◽  
Type 3

Dynamical changes of chemical reactions which occurred during combustion process in Circulating Fluidized Bed boiler (CFB) has been modelled using adjacency matrix of Fuzzy Autocatalytic Set (FACS) of fuzzy graph type-3. Analysis of sequence of changes in the reactions at time t through Perron-Frobenious eigenvector (PFE) of the matrix in the Graph Dynamic Algorithm (GDA) shows that end-product of the combustion process in the CFB namely Water and Hydrogen is not really potrayed the real process.  Therefore, in this study, transition matrix of FACS is utilized to analyse the dynamical changes of the reactions and the GDA is modified and improvised and known as Interactive Graph Dynamics (IGD) is subsequently use to facilitate the analysis. The result shows that by using the transition matrix of FACS, the end-product of the combustion process in CFB is in accordance to the real process. Whilst the IGD is able to reduced computer running time as compared to the existing GDA. This paper describes the development of IGD and the analysis of sequence of changes of chemical reactions during combustion process in CFB by using transition matrix with the helped of MATLAB. 

Optimize Selected of Anti-Attrition Ridge Parameters through Numerical Simulation in CFB Boiler Blended with Waste Sludge

2014 ◽  
Vol 525 ◽  
pp. 222-226 ◽  
Author(s):  
Bo Lou ◽  
Hai Liang Diao ◽  
Si Ke Wu
Keyword(s):  
Particle Trajectory ◽  
Circulating Fluidized Bed ◽  
Three Dimensional ◽  
Guangdong Province ◽  
Furnace Wall ◽  
Combustion Model ◽  
Cfb Boiler ◽  
Waste Sludge ◽  
Ring Core ◽  
Stochastic Particle

Combustion in boiler blended with waste sludge can cause serious abrasion in the furnace. In this paper, Fluent6.3 was applied to establish three-dimensional numerical combustion model based on k-ε turbulence equations and Lagrangian stochastic particle trajectory to analyze a CFB (Circulating Fluidized Bed) boiler of a power plant in Guangdong province. The results show that anti-attritions will break the ring-core adherent regurgitation of the particles thus reducing erosion of particles made to the furnace wall. Furthermore, a setting of three anti-attrition ridges can prolongate the life of the wall by 2.49 times. Increasing numbers and the length of ridges are beneficial to wall, which should be limited shorter than 150mm duo to heat tube slagging, and implementing a shape of trapezoid instead of rectangle all are derived as enhancements to the feature of anti-attrition of CFB.

Three-Dimensional Modeling and Model Validation of Circulating Fluidized Bed Combustion

2003 ◽  
Author(s):  
Kari Myo¨ha¨nen ◽  
Timo Hyppa¨nen ◽  
Jouni Miettinen ◽  
Riku Parkkonen
Keyword(s):  
Heat Flux ◽  
Fluidized Bed ◽  
Large Scale ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Three Dimensional ◽  
Hot Water ◽  
Combustion Model ◽  
Process Conditions ◽  
Model Parameters

This paper presents a three-dimensional, steady state combustion model for a circulating fluidized bed (CFB) furnace and several calculation cases which have been used for the validation of the model. The model includes essential submodels to describe the complex combustion process in a circulating fluidized bed boiler. These include the hydrodynamics of the bed, devolatilization of fuel, combustion of char, combustion of hydrocarbons, carbon monoxide and hydrogen, calcination and sulfation, fragmentation and attrition of solids, heat transfer, overall mass balance of the furnace, and three-dimensional balance equations based on the finite volume method. The code was initially developed in 1989, and it has been updated and improved over the years as new methods and new information have become available. The model is used for increasing process knowledge and for studying such phenomena inside the furnace which are often difficult or impossible to study by direct measurements. The knowledge obtained is then applied to optimize boiler design and process performance in terms of efficiency, economy and environmental issues. Reliable experiments and measurements in commercial boilers are used for the validation of the model and for tuning the model parameters. For the validation of a three-dimensional model, extensive profile measurements of the various parts of the furnace are required. This paper presents validation studies for an 80 MWth hot water boiler burning bituminous coal and for a 235 MWe subcritical boiler burning lignite. The measurements with these units included profile measurements of heat flux, pressure, temperature and gas composition under different process conditions. The model was tuned according to the measurements and used for the prediction of the heat flux profile of a large scale supercritical CFB boiler.

scholarly journals Optimization of Fluidization State of a Circulating Fluidized Bed Boiler for Economical Operation

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 376 ◽  
Author(s):  
Xuemin Liu ◽  
Hairui Yang ◽  
Junfu Lyu
Keyword(s):  
Energy Consumption ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Large Scale ◽  
Circulating Fluidized Bed ◽  
Combustion Efficiency ◽  
Calculation Model ◽  
Combustion Model ◽  
Control Cost ◽  
Coal Consumption

To reduce the auxiliary power consumption and improve the reliability of large-scale circulating fluidized bed (CFB) boilers, we developed energy-saving CFB combustion technology based on the fluidization state re-specification. A calculation model of coal comminution energy consumption was used to analyze the change in comminution energy consumption, and a 1D CFB combustion model was modified to predict the operation parameters under the fluidization state optimization conditions. With a CFB boiler of 480 t/h, the effect of fluidization state optimization on the economical operation was analyzed using the above two models. We found that combustion efficiency presents a nonmonotonic trend with the change in the bed pressure drop and feeding coal size. There are an optimal bed pressure drop and a corresponding feeding coal size distribution, under which the net coal consumption is the lowest. Low bed pressure drop operation achieved by reducing the coal particle size is not beneficial to SO2 and NOx emission control, and the pollutant control cost increases. The effect of fluidization state optimization on the gross cost of power supply can be calculated, and the optimal bed pressure drop can be obtained.

Data-driven modelling and fuzzy multiple-model predictive control of oxygen content in coal-fired power plant

2016 ◽  
Vol 39 (11) ◽  
pp. 1631-1642 ◽  
Author(s):  
Huang Xiaoying ◽  
Wang Jingcheng ◽  
Zhang Langwen ◽  
Wang Bohui
Keyword(s):  
Power Plant ◽  
Real Time ◽  
Oxygen Content ◽  
Predictive Control ◽  
Tracking Control ◽  
Process Model ◽  
Combustion Process ◽  
Data Driven ◽  
Multiple Model ◽  
Real Process

In the combustion system of a boiler, oxygen content in the flue gas is a significant economic parameter for combustion efficiency. As a combustion system is highly complex and there are many constraints in a real process, traditional control cannot achieve satisfying performance in the practical oxygen content tracking control problem. In this paper, we build a combustion process model with a data-driven method and present a multiple-model-based fuzzy predictive control algorithm for the oxygen content tracking control. The combustion process model is presented as a multiple-model form, which can represent the real process more accurately. A data-driven method with fuzzy c-means clustering and subspace identification is used to identify the model parameters. Then, model predictive control integrated with a fuzzy multiple-model is used to control the oxygen content tracking problem. As the coal manipulated variable is decided by the load demand in the real process, a real-time measured value is applied to the process. All data used to obtain the process model is historical real-time data generated from a 300-MW power plant in Gui Zhou Province, China. Real-time simulation results on the 300-MW power plant show the effectiveness of the modelling and control algorithms proposed in this paper.

Improvement on Dynamic Combustion Model of Dense-Phase Zone in Circulating Fluidized Bed Boiler Furnace

2005 ◽  
Author(s):  
Weiping Yan ◽  
Xining Yu ◽  
Libao Yin
Keyword(s):  
Circulating Fluidized Bed ◽  
Combustion Model ◽  
Heating Process ◽  
Dense Phase ◽  
Phase Zone ◽  
Boiler Furnace ◽  
Cfb Boiler ◽  
Bed Temperature ◽  
Proposed Model ◽  
Dynamic Combustion

A novel method for predicting the dynamic combustion performances of dense-phase zone in CFB furnace are proposed based on the improvements of the previous models. The coal particle heating process, the time delay and the subsequent heat release as raw coal with wide size distribution admitted into the furnace are adequately taken into account in the proposed model. The bed temperature responses to the variations of coal firing rates are predicted and compared to the measured data from a 220t/h CFB boiler.

Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler

TAPPI Journal ◽  
2010 ◽  
Vol 9 (6) ◽  
pp. 24-30 ◽  
Author(s):  
NIKLAS BERGLIN ◽  
PER TOMANI ◽  
HASSAN SALMAN ◽  
SOLVIE HERSTAD SVÄRD ◽  
LARS-ERIK ÅMAND
Keyword(s):  
Circulating Fluidized Bed ◽  
Black Liquor ◽  
Chloride Content ◽  
Pilot Scale ◽  
High Energy ◽  
Kraft Lignin ◽  
High Energy Density ◽  
Alkali Chloride ◽  
Cfb Boiler ◽  
Solid Biofuel

Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cofiring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.

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