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.

Experience on Combustion and Co-Combustion of Greek Brown Coal in Fluidized Bed Facilities

2003 ◽  
Author(s):  
Emmanuel Kakaras ◽  
Panagiotis Grammelis ◽  
George Skodras ◽  
Panagiotis Vourliotis
Keyword(s):  
Fluidized Bed ◽  
Brown Coal ◽  
Thermal Capacity ◽  
Operating Conditions ◽  
Low Rank ◽  
Biomass Combustion ◽  
Low Grade ◽  
Fluidised Bed ◽  
Research Activities ◽  
Combustion Tests

The paper aims to present the experience gained from the combustion trials of Greek brown coal in different installations, both in semi-industrial and laboratory scale. Specifically, these research activities are separated in two parts, i.e. combustion tests using only brown coal and co-combustion tests with brown coal and biomass. Combustion tests with Greek lignite were realised 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. The results include the determination of operating conditions to achieve proper fuel burnout, the examination of the influence of air staging on the temperature distribution inside the reactor and the investigation of the combustion behaviour of the particular fuel type and emitted pollutants. Several conclusions are drawn concerning the necessary modifications and requirements of the plant layout when a large scale CFBC installation is designed to utilize low grade brown coal. Co-combustion tests with Greek xylitic lignite and waste wood were carried out in the 1 MWth CFBC installation of AE&E, in Austria. During the tests, oxygen concentration and CO, SO2, N2O and NOX emissions were continuously monitored. Ash samples were collected and analysed for heavy metals content in ICP-AES spectrophotometer. The improved combustion behaviour of this lignite type was more than evident, since it has lower moisture content and increased calorific value. In all co-combustion tests, low emissions of gaseous pollutants were obtained and metal element emissions were lower than the corresponding values anticipated by the guidelines. In addition, lab-scale co-combustion tests of Greek pre-dried lignite with biomass were accomplished in a bubbling fluidised bed. The main purpose of these experiments was to examine ash melting problems and differentiation to the emitted pollutants due to biomass addition. The obtained results of all aforementioned activities showed that fluidised bed is the appropriate combustion technology to efficiently exploit the low quality Greek brown coal either alone or in conjunction with other biomass materials.

Retrofitting 25T/h Pulverized Coal-Fired Boiler Into 35T/h Circulating Fluidized Bed Boiler for Burning Mixture of Coal and Bagasse

2005 ◽  
Author(s):  
Han-Ping Chen ◽  
Xian-Hua Wang ◽  
Shi-Hong Zhang ◽  
De-Chang Liu ◽  
Yu-Hua Lai ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Combustion Efficiency ◽  
Economic Benefits ◽  
Pulverized Coal ◽  
Industrial Wastes ◽  
Pollutant Emission ◽  
Fluidized Bed Combustion ◽  
Circulating Fluidized Bed Boiler ◽  
Combustion Technology

In China, there are a large number of pulverized coal-fired industrial boilers, whose steam capacities are usually relatively small. These boilers can burn only high-grade coal and have low combustion efficiency. Furthermore, the combustion emissions, such as SO2 and NOx, pollute the environment severely. Therefore it is very important and urgent to adopt economically efficient and environmentally friendly technologies to retrofit these boilers. At the same time, there are many industrial wastes, such as bagasse, wood waste, rubbish, petroleum coke and so on, need burning disposal in China. Fluidized bed combustion technology is a kind of clear combustion technology, which has many advantages, such as excellence fuel flexibility, high combustion efficiency, low pollutant emission and good turndown capability etc. So, adopting fluidized bed combustion technology, retrofitting pulverized coal-fired boiler into fluidized bed boiler can realize pure burning various wastes or co-firing with coal, which should have great economic benefits and social benefits. And the application prospect of the method is also extensive. The State Key Laboratory of Coal Combustion has successfully retrofitted a 25t/h pulverized coal-fired boiler into circulating fluidized bed boiler with in-bed tubes and downward exhaust cyclone. The retrofitted boiler can burn mixture of coal and bagasse and the steam capacity reaches 35t/h. This paper presents the retrofitting measures and the operation status of the boiler after retrofitting.

Fluidized bed combustion systems for power generation and other industrial applications

2003 ◽  
Vol 217 (1) ◽  
pp. 9-18 ◽  
Author(s):  
A. J. Minchener
Keyword(s):  
Power Generation ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Industrial Applications ◽  
Coal Waste ◽  
Fluidized Bed Combustion ◽  
Bubbling Fluidized Bed ◽  
The Status ◽  
Market Opportunities ◽  
Derivatives Of

Fluidized bed combustion (FBC) in various forms has been used to burn all types of coal, coal waste and a wide variety of other fuels, either singly or cofired with coal. FBC boilers are currently available commercially in the capacity range from 1 MWth to over 250 MWe and continue to be adopted for a variety of commercial, industrial and power generation applications. There are two main derivatives of FBC, namely bubbling fluidized bed combustion (BFBC) and circulating fluidized bed combustion (CFBC). There are also several hybrid systems and pressurized versions of both BFBC and CFBC. The status of these different systems, with some now fully commercial and some still under development, is described, with projections made for future development requirements and market opportunities.

Experimental Studies on Combustion of Cattle Manure in a Fluidized Bed Combustor

1987 ◽  
Vol 109 (2) ◽  
pp. 49-57 ◽  
Author(s):  
K. Annamalai ◽  
M. Y. Ibrahim ◽  
J. M. Sweeten
Keyword(s):  
Fluidized Bed ◽  
Fossil Fuels ◽  
Experimental Studies ◽  
Heat Content ◽  
Fluidized Bed Combustion ◽  
Volatile Solids ◽  
Combustion Technology ◽  
Solids Content ◽  
Combustion Tests ◽  
Fluidized Bed Combustor

Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels. But the heat content of manure is rather low. Since, the fluidized bed combustion technology has been used for the energy conversion of marginal fuels, such a technology is being explored for the combustion of feedlot manure. A fluidized bed combustor of 0.15 m (6 in.) diameter was used for the combustion tests on manure. Experiments were conducted with −20 to +20 percent excess air and at bed temperatures ranging from 600°C (1112°F) to 800°C (1472°F). Experimental data revealed that the gasification efficiencies ranged from 90 to 98 percent, while the combustion efficiencies varied from 45 to 85 percent. Higher combustion efficiencies were obtained with decreased volatile solids content of manure. The low combustion efficiencies are attributed to the limited residence time available for the volatiles to burn within the reactor.

scholarly journals Development of Methane and Nitrous Oxide Emission Factors for the Biomass Fired Circulating Fluidized Bed Combustion Power Plant

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Chang-Sang Cho ◽  
Jae-Hwan Sa ◽  
Ki-Kyo Lim ◽  
Tae-Mi Youk ◽  
Seung-Jin Kim ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Fluidized Bed ◽  
Emission Factor ◽  
Circulating Fluidized Bed ◽  
Wood Chip ◽  
Emission Factors ◽  
Fluidized Bed Combustion ◽  
Cfb Boiler ◽  
Combustion Technology ◽  
The Subject

This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB) boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH4), Nitrous oxide (N2O). The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF), RDF and Refused Plastic Fuel (RPF) of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH4and N2O were measured to be 2.78 ppm and 7.68 ppm, respectively. The analyzed values and data collected from the field survey were used to calculate the emission factor of CH4and N2O exhausted from the CFB boiler. As a result, the emission factors of CH4and N2O are 1.4 kg/TJ (0.9–1.9 kg/TJ) and 4.0 kg/TJ (2.9–5.3 kg/TJ) within a 95% confidence interval. Biomass combined with the combustion technology for the CFB boiler proved to be more effective in reducing the N2O emission, compared to the emission factor of the CFB boiler using fossil fuel.

scholarly journals N2O and NO Emissions from CFBC Cofiring Dried Sewage Sludge, Wet Sewage Sludge with Coal and PE

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Zhiwei Li ◽  
Hongzhou He
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Pilot Scale ◽  
Conversion Ratio ◽  
Fluidized Bed Combustion ◽  
Mixed Fuel ◽  
Higher Temperature ◽  
Circulating Fluidized Bed Combustion ◽  
No Emissions

Experiments on cofiring dried sewage sludge, wet sewage sludge with coal and polyethylene (PE) were carried out on a pilot scale 0.15MWt circulating fluidized bed combustion (CFBC) plant, and the influence of furnace temperatures, cofiring rates on N2O and NO emissions was investigated. Temperature is an effective parameter influencing N2O emission, and higher temperature leads to significant N2O reduction and decrease of conversion ratio of fuel-N to N2O. Increasing in cofiring rates leads to higher nitrogen content in the mixed fuel, which could result in higher NO and N2O emissions from combustion. With more sewage sludge addition, higher NO but lower N2O emissions are observed. N2O emission from cofiring wet sewage sludge with coal is higher than that from cofiring dried sewage sludge with coal and PE, and fuel-N conversion ratio to N2O and NO is much higher in cofiring wet sewage sludge with coal than that in cofiring dried sewage sludge with coal and PE.

scholarly journals Combustion of low grade fractions of Lubnica coal in fluidized bed

2012 ◽  
Vol 16 (1) ◽  
pp. 297-311
Author(s):  
Milica Mladenovic ◽  
Dragoljub Dakic ◽  
Stevan Nemoda ◽  
Rastko Mladenovic ◽  
Aleksandar Eric ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Environmental Protection ◽  
Fluidized Bed ◽  
Brown Coal ◽  
Circulating Fluidized Bed ◽  
Combustion Characteristics ◽  
Low Grade ◽  
Fluidized Bed Combustion ◽  
Furnace Temperature ◽  
Industrial Apparatus

In this paper a method of examination of fuel suitability for fluidized bed combustion is presented. The research of combustion characteristics of low grade fractions of Lubnica brown coal in the fluidized bed by the aforementioned methodology has been carried out on a laboratory semi-industrial apparatus of 200 kWt. Description of the experimental fluidized bed combustion facility is given, as well as experimental results, with the focus on furnace temperature distribution, in order to determine the location of the zone of intensive combustion. Based on investigation results, which are focused on combustion quality (combustion completion) as well as on satisfying the environmental protection criteria, it can be stated that the investigated coal is suitable for burning in bubbling, as well as in circulating fluidized bed.

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