Combustion Tests on a Blend of Liquid Refinery Residues and Coal: CFBC Operation Behaviour and Emissions Characteristics With Special Emphasis on the Intermediate Species CxHy, HCN and NH3

2005 ◽  
Author(s):  
M. Kretschmann ◽  
Chr. Barczus ◽  
V. Scherer
Keyword(s):  
Combustion Chamber ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Thermal Capacity ◽  
Gas Analysis ◽  
Current Paper ◽  
Hard Coal ◽  
Nox Formation ◽  
Secondary Air ◽  
Combustion Tests

Investigations on the combustion of a blend of liquid refinery residues and a hard coal are presented in the current paper. The experiments were done in an atmospheric circulating fluidized bed combustor (CFBC) with a thermal capacity of 100 kW. The operation behaviour and pollutant formation characteristics are determined using axial profile measurements at 19 different ports along the combustion chamber. The measurement campaign included the variation of the primary to secondary air ratio, the global air to fuel ratio, the residence time in the primary zone, the overall temperature of the combustion chamber and the Ca/S ratio. The current paper concentrates on results obtained at primary air ratio of 0.65, an overall air ratio of 1.1, a mean combustion temperature of 850°C and a Ca/S-ratio of 0. Measurement of the flue gas components O2, CxHy, CO, CO2, H2, NOx, N2O, NH3 and SO2 are made by standard gas analysing techniques. In order to detect the specific hydrocarbon species produced and oxidized during the combustion process a Fourier Transformation Infrared Spectrometer (FTIR) extends the existing gas analysis system. The gas species measured by FTIR-Spectroscopy are CH4, C2H2, C2H4, C2H6, C3H6 and C3H8. Also the important precursors for the NOx-Formation HCN and NH3 are examined with the FTIR-Spectrometer in the primary and secondary zone. The current experiments are compared with results obtained by burning liquid refinery residues only, with special regard to the consumption of the nitrogenous intermediates HCN and NH3.

Combustion of Refinery Residues in a CFB-Combustor: Measurement of Intermediate Species Using FTIR

2003 ◽  
Author(s):  
Christian Barczus ◽  
Bjo¨rn Henning ◽  
Viktor Scherer
Keyword(s):  
Combustion Chamber ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Thermal Capacity ◽  
Liquid Fuels ◽  
Gaseous Species ◽  
Nox Formation ◽  
Secondary Air ◽  
Fluidized Bed Combustor

Investigations have been performed to show the feasibility of burning refinery residues (calcined petroleum coke and liquid residues) in a circulating fluidized bed combustor. These experiments were done in a CFBC system with a thermal capacity of 100 kW. The unit has been equipped with an additional dosing system for liquid fuels including a newly developed fuel lance. The pollutant formation characteristics are determined using axial profile measurements at 19 different ports along the combustion chamber. To optimize the combustion process and to minimize gaseous pollutants, several operating parameters of the system are varied independently. These parameters are the primary to secondary air ratio, the global air to fuel ratio, the residence time in the primary zone, the overall temperature of the combustion chamber and the Ca/S ratio. Measurements of the flue gas components O2, CxHy, CO, CO2, H2, NOx, N2O, NH3 and SO2 are performed by standard gas analysing techniques. It is important to note that the system is equipped with a Fourier Transform Infrared Spectrometer (FTIR) to qualitatively and quantitatively determine selected gaseous species which are essential for the formation and consumption of N2O and other pollutants. The gas species measured by FTIR-Spectroscopy are CH4, C2H2, C2H4, C2H6, C3H6 and C3H8. Also the important precursors for the NOx-formation HCN and NH3 are examined with the FTIR-Spectrometer. The investigations demonstrate that (liquid) refinery residues can be burned successfully as a monofuel within the circulating fluidized bed combustor. The emissions of all pollutants detected are at a low level.

A 3D Model of Combustion in Large-Scale Circulating Fluidized Bed Boilers

2004 ◽  
Vol 2 (1) ◽  
Author(s):  
Karsten Luecke ◽  
Ernst-Ulrich Hartge ◽  
Joachim Werther
Keyword(s):  
Combustion Chamber ◽  
Fluidized Bed ◽  
Large Scale ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Cross Sectional ◽  
Secondary Air

In a circulating fluidized bed (CFB) combustor the reacting solids are locally fed into the combustion chamber. These reactants have to be dispersed across the reactor's cross-sectional area. Since the rate of mixing is limited this leads to a mal-distribution of the reactants and to locally varying reaction conditions. In order to describe the influence of mixing a three-dimensional model of the combustion chamber is suggested. The model is divided into three sub-topics. First, the flow structure in terms of local gas and solids velocities and solids volume concentrations is described. Second, mixing of the solids and the gas phase is quantified by defining dispersion coefficients, and finally the combustion process itself, i.e. the reaction kinetics, is modelled. The model was validated against data from measurements in the large-scale combustor of Chalmers University of Technology in Göteborg/Sweden. Insufficient fuel mixing generated mal-distributions of locally released volatiles, which were the basis for the uneven reactants distribution at steady-state. In the case of two-stage operation, the injected secondary air did not reach immediately the reactor's center but was slowly mixed with the main gas flow. The concentration gradients hardly vanish before the exit of the combustion chamber.

scholarly journals Experimental determination of a mass loss of biomass pellets at different temperatures of the combustion chamber combusted in a stream of inert material

2019 ◽  
Vol 82 ◽  
pp. 01007
Author(s):  
Katarzyna Kaczyńska ◽  
Konrad Kaczyński ◽  
Piotr Pełka
Keyword(s):  
Mass Loss ◽  
Combustion Chamber ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Circulating Fluidized Bed ◽  
Combustion Process ◽  
Inert Material ◽  
Mass Rate ◽  
Different Temperatures

In the herein paper, research on the mass loss of biomass pellets is presented. The research was carried out on a specially constructed test stand. In the research three types of pellet fuels were used, which were made of oak sawdust, sunflower husk and straw. The research was carried out at three different temperatures of the combustion chamber: 850°C, 750°C and 650°C. The research was carried out without inert material and mass rate flow Gs=2,5kg/m2s and Gs=5kg/m2s. Quartz sand was the inert material. It was expected that an increase in the temperature prevailing in the combustion chamber would accelerate the process of mass loss of the biomass pellet combustion. However, the results of the experiment indicated that this is not the case in every analyzed case. The mass flow rate of inert material intensifies the combustion process and accelerates the biomass pellets made of oak sawdust mass loss, but increasing the temperature in the combustion chamber accelerates the process of biomass pellets mass loss more than the mass flow rate of inert material. Based on the experimental tests carried out, it was found that biomass can be combusted in circulating fluidized bed boilers, albeit due to the diversified chemical composition of the biomass (alkali content), the boiler should be operated in such a way as to prevent the softening and melting temperature of the ash being exceeded.

NOx Emission of Diesel Fuel Blended with Different Saturation Degrees of Biofuel and with Oxygenator

2014 ◽  
Vol 660 ◽  
pp. 397-401 ◽  
Author(s):  
Mohd Fareez Edzuan bin Abdullah ◽  
Mohd Hisyamuddin bin Sulaiman ◽  
Noor Aliah Binti Abdul Majid
Keyword(s):  
Diesel Fuel ◽  
Flue Gas ◽  
Combustion Process ◽  
Nox Emission ◽  
Dominant Factor ◽  
Compression Ignition ◽  
Nox Formation ◽  
Fuel Blends ◽  
Combustion Tests ◽  
Co Emission

This paper discusses the nitrogen oxides (NOx) emission characteristics of compression ignition diesel engine operating on diesel fuel blends with different saturation degrees of biofuel and with methanol. In order to investigate the dominant factor of increased NOx in biofuels, diesel combustion tests were conducted under idling condition and the tailpipe exhaust emissions were measured by a flue gas analyzer. The general trend where NOx emission increased and reduced carbon monoxide (CO) emission in the biofuel and methanol blend cases were observed. The NOx emission levels increased as the biofuel saturation degree decreased, where it may be suggested that the prompt NOx mechanism is significant in total NOx formation of biofuel combustion process.

Evolution of the Structure and Mechanical Strength of a Coal Particle During Combustion in the Atmosphere of Air and the Mixture of Oxygen and Carbon Dioxide / Ewolucja Struktury Oraz Wytrzymałości Mechanicznej Ziarna Węgla Podczas Spalania W Atmosferze Powietrza Oraz Mieszaninie Tlenu I Dwutlenku Węgla

2013 ◽  
Vol 58 (3) ◽  
pp. 673-690
Author(s):  
Piotr Pełka ◽  
Grzegorz Golański ◽  
Paweł Wieczorek
Keyword(s):  
Carbon Dioxide ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Sudden Change ◽  
Combustion Process ◽  
Ambient Air ◽  
Hard Coal ◽  
Atomic Force ◽  
Coal Particles ◽  
The Moment

Abstract The research was conducted on the basis of four different types of hard coal and one type of brown coal. There are typical coals commonly used as fuel in Polish CFB boilers. The combustion process was conducted at a temperature of 850°C and the atmosphere of ambient air as well as in the mixture of oxygen and carbon dioxide in different proportions. The research was carried out using specially prepared cubical coal particles with measurements of 15×15mm and also 10×10 mm. The change of the mechanical properties was analyzed based on three parameters, i.e. compression strength, Vickers hardness and fracture toughness. The analysis was supplemented by microscopic images of the surface of the particles using an atomic force microscope. The results obtained clearly indicated the mechanical changes of the coal during its combustion, particularly at the moment of ignition of the char. Moreover, the results correlate very well with the processes of coal comminution that have been described by other authors (Basu, 1999; Chirone et al., 1991) during combustion in the circulating fluidized bed and also explain the sudden change of susceptibility to erosion in the conditions with and without combustion. The measured values can be used as strength parameters in the modelling of the mass loss of coal particles in conditions of circulating fluidized bed combustor that are hard to describe.

scholarly journals Effect of Hard Coal Combustion in Water Steam Environment on Chemical Composition of Exhaust Gases

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6530
Author(s):  
Bartosz Ciupek ◽  
Karol Gołoś ◽  
Radosław Jankowski ◽  
Zbigniew Nadolny
Keyword(s):  
Chemical Composition ◽  
Combustion Chamber ◽  
Coal Combustion ◽  
Mass Concentration ◽  
Combustion Process ◽  
Hard Coal ◽  
Nitric Oxides ◽  
Water Steam ◽  
Exhaust Gases ◽  
Academic Paper

This academic paper revolves around the results of research on the change in emission parameters of the used heating boiler following the introduction of the overheated water stream, which had an impact on different emission parameters. The research results provide an insight into the hard coal combustion process, which had a significant impact on the change in the chemical composition of exhaust gases: it contributed to the lower mass concentration of the emitted dust and black carbon (PM) as well as nitric oxides (NOx) while, at the same time, playing a significant role in increasing the mass concentration of the emitted carbon oxide (CO). Two types of devices were used for the purposes of conducting the research at hand: a boiler with an automatic fuel feeding system with one combustion chamber and a boiler with a combustion chamber and an afterburning chamber fitted over it. Apart from the measurements of mass concentration of the emitted harmful substances, the research also focused on measurements of temperature inside the combustion and afterburning chambers, as well as the temperature of exhaust gases and their oxygen content. As part of the research, water steam was introduced to the combustion and afterburning chambers at the flow rate of 0.71 kg/h and 3.60 kg/h for boilers operating at a minimum power of 30% and a nominal power of 100%. An original steam generator with an overheated water steam production range from 0.71 kg/h to 3.60 kg/h was used to create and feed the water steam. The efficiency of the combustion process was calculated using the obtained results for each operating configuration of a given boiler.

scholarly journals Fluidized bed combustion with the use of Greek solid fuels

2003 ◽  
Vol 7 (2) ◽  
pp. 33-42
Author(s):  
Emmanuel Kakaras ◽  
Panagiotis Grammelis ◽  
George Skodras ◽  
Panagiotis Vourliotis
Keyword(s):  
Fluidized Bed ◽  
Brown Coal ◽  
Circulating Fluidized Bed ◽  
Pilot Scale ◽  
Thermal Capacity ◽  
Low Rank ◽  
Fluidized Bed Combustion ◽  
Bubbling Fluidized Bed ◽  
Combustion Technology ◽  
Combustion Tests

The paper is an overview of the results obtained up to date from the combustion and co-combustion activities with Greek brown coal in different installations, both in semi-industrial and laboratory scale. Combustion tests with Greek lignite were realized in three different Circulating Fluidized Bed Combustion (CFBC) facilities. Low rank lignite was burned in a pilot scale facility of approx. 100kW thermal capacity, located in Athens (NTUA) and a semi-industrial scale of 1.2 MW thermal capacity, located at RWE's power station Niederaussem in Germany. Co-combustion tests with Greek xylitic lignite and waste wood were carried out in the 1 MWth CFBC installation of AE&E, in Austria. Lab-scale co-combustion tests of Greek pre-dried lignite with biomass were accomplished in a bubbling fluidized bed in order to investigate ash melting problems. The obtained results of all aforementioned activities showed that fluidized bed is the appropriate combustion technology to efficiently exploit the low quality Greek brown coal either alone or in conjunction with biomass species.

The Application of SunyPCC800 in CFB Boilers

2012 ◽  
Vol 535-537 ◽  
pp. 779-782
Author(s):  
Yu Ping Yang ◽  
Yun Feng Xu
Keyword(s):  
Fluidized Bed ◽  
High Efficiency ◽  
Circulating Fluidized Bed ◽  
Air Flow ◽  
Combustion Process ◽  
Control Effect ◽  
Coal Quality ◽  
Loop Control ◽  
Combustion Technology ◽  
Secondary Air

The combustion technology of Circulating Fluidized Bed Boilers is a Cleaning and high efficent of Coal Powder Combustion technology. Traditional control methods can hardly get ideal control effect. To Realize datas reading and writing by self_control software throgh DCS, when coal quality, loading altered, realized automatic closed-loop control of combustion process of circulating fluidized bed, to implement primary air flow, secondary air flow and air-induced automatic cordinated control and reached cleaning of coal quality and combustion high efficiency.

Influence of Excess Air Factor on NOx Emissions From a 200 kW Swirl Burner

2015 ◽  
Author(s):  
Abdallah Ahmed ◽  
Essam E. Khalil ◽  
Hatem Kayed ◽  
Mohamed M. A. Hassan
Keyword(s):  
Combustion Chamber ◽  
Air Temperature ◽  
Gas Turbines ◽  
Flame Temperature ◽  
Combustion Process ◽  
Operating Conditions ◽  
Swirl Burner ◽  
Nox Formation ◽  
Excess Air ◽  
Thermal Nox

NOx formation during the combustion process occurs mainly through the oxidation of nitrogen in the combustion air (thermal NOx) and through oxidation of nitrogen with the fuel (prompt NOx). The present study aims to investigate numerically the problem of NOx pollution using a model of combustion chamber with 200 kW swirl burner utilizing propane as fuel. The importance of this problem is mainly due to its relation to the pollutants produced by boiler furnaces and gas turbines, which used widely in thermal industrial plants. Governing conservation equations of mass, momentum and energy, and equations representing the transport of species concentrations, turbulence, combustion and radiation modeling in addition to NOx modeling equations were solved together to present temperature and OH distribution inside the combustion chamber, and the NOx concentration at the combustion chamber exit, at various operating conditions of fuel to air ratio. In particular, the simulation provided more insight on the correlation between the peak flame temperature and the thermal NOx concentration. The results have shown that the peak flame temperature and NOx concentration decrease as the excess air factor λ increases. When considering a fixed value of mass flow rate of fuel, the results show that increasing λ results in a maximum value of thermal NOx concentration at the exit of the combustion chamber at λ = 1.05. As the combustion air temperature increases, and the thermal NOx concentration increases sharply. However, when λ exceeds this value NOx concentration starts to decrease due to the combustion air temperature decrease.

Reaction of Fuel NOx Formation for Gas Turbine Conditions

1998 ◽  
Vol 120 (3) ◽  
pp. 474-480 ◽  
Author(s):  
T. Nakata ◽  
M. Sato ◽  
T. Hasegawa
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Combustion Process ◽  
Combined Cycle ◽  
Inlet Section ◽  
Mixing Condition ◽  
Nox Formation ◽  
Air Inlet ◽  
Secondary Air ◽  
Fuel Nox

Ammonia contained in coal-gasified fuel is converted to nitrogen oxides (NOx) in the combustion process of a gas turbine in integrated coal gasification combined cycle (IGCC) system. Research data on fuel-NOx formation are insufficient, and there still remains a wide explored domain. The present research aims at obtaining fundamental knowledge of fuel-NOx formation characteristics by applying reaction kinetics to gas turbine conditions. An instantaneous mixing condition was assumed in the cross section of a gas turbine combustor and both gradual mixing condition and instantaneous mixing condition were assumed at secondary air inlet section. The results may be summarized as follows: (1) in the primary combustion zone under fuel rich condition, HCN and other intermediate products are formed as ammonia contained in the fuel decomposes; (2) formation characteristics of fuel-NOx are affected by the condition of secondary air mixing; and (3) the conversion ratio from ammonia to NOx declines as the pressure inside the combustor rises under the condition of gradual mixing at the secondary air inlet. These results obtained agreed approximately with the experimentation.

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