NOx Emissions From Combustion of High Sulfur Lignite in an ABFBC Test Rig

2003 ◽  
Author(s):  
Nevin Selc¸uk ◽  
Aykan Batu ◽  
Olcay Oymak
Keyword(s):  
Fluidized Bed ◽  
Nox Reduction ◽  
Volatile Matter ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Fluidized Bed Combustion ◽  
Test Rig ◽  
Bubbling Fluidized Bed ◽  
Combustion Technology ◽  
Fluidized Bed Boilers

NOx emissions from fluidized bed combustion of various coals have extensively been investigated and well documented. However, NOx emissions from combustion of Turkish lignites with high ash, volatile matter and sulfur contents have not drawn much attention to date. Recent trend in utilization of indigenous lignites in fluidized bed boilers necessitated investigation of pollutant emissions and adaptation of fluidized bed combustion technology to these lignites. In this study, experimental results of various runs pertaining to the formation and emission of NOx from METU 0.3 MWt Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) test rig burning typical indigenous lignites; Aydin without limestone addition and Beypazari with and without limestone addition are presented. NOx profiles along the combustor show that concentrations are higher in bed compared to those in freeboard and that conditions leading to higher unburned volatiles in freeboard enhances NOx reduction in that region. Limestone addition results in higher concentrations of NOx in bed but lower concentrations in freeboard, albeit insignificantly.

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.

Gas-Mixing in Bubbling Fluidized Bed Combustors: Hydrodynamics and Macromixing Associated With Bubble Bursting at the Bed Surface

2003 ◽  
Author(s):  
R. Solimene ◽  
A. Marzocchella ◽  
P. Salatino ◽  
R. Ragucci
Keyword(s):  
Fluidized Bed ◽  
Fluid Dynamic ◽  
Volatile Matter ◽  
Solid Fuels ◽  
Flow Structures ◽  
Specific Reference ◽  
Gas Mixing ◽  
Fluidized Bed Combustion ◽  
Bubble Bursting ◽  
Bubbling Fluidized Bed

Gas-mixing phenomena may play a significant role in fluidized bed combustion of solid fuels. Issues associated with gas mixing include: a) effectiveness of mass transfer between the bubble and the emulsion phases in the bed; b) degree of mixing between segregated gaseous streams in plume-like or bubbly flow in the bottom bed; c) extent of mixing between segregated gaseous pockets/streams in the splashing zone or in the upper freeboard. Among the others, issues b) and c) turn out to be relevant to fluidized bed combustion of high-volatile solid fuels (biomass, RDF, etc.). In this case, the rate of gas mixing often overcomes intrinsic kinetics as the rate-controlling step in volatile matter burn-out, especially under “stratified” combustion conditions. Despite several and significant contributions to the subject, understanding of gas-mixing in bubbling fluidized beds is still poor and calls for additional investigation. The present work aims at investigating gas-mixing in bubbling fluidized bed with specific reference to the above issue c). A laser assisted imaging technique has been used to characterize the hydrodynamic patterns associated with the bursting of either isolated bubbles or couples of closely time-delayed bubbles at the surface of a fluidized bed. Quantitative image analysis procedures were exploited in order to assess parameters defining the general fluid-dynamic behaviour and macromixing of the bubble-generated gas pockets with the mainstream gas. The formation of toroidal flow structures upon bubble bursting is highlighted in the case of isolated bubbles. The toroidal pockets entrain mainstream gas and grow accordingly while rising along the splash zone. Toroidal flow structures are observed also in the case of couples of closely time-delayed bubbles, but interference between leading and trailing pockets leads to more complex structures characterized by multiple incoherent eddies. The relevance of macromixing to volatile matter burning under conditions of stratified fluidized bed combustion is assessed and discussed.

scholarly journals Bubbling fluidized bed combustion of Syncrude coke

1987 ◽  
Author(s):  
E J Anthony ◽  
H A Becker ◽  
R K Code ◽  
R W McCleave ◽  
J R Stephenson
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Combustion ◽  
Bubbling Fluidized Bed

Fate of bromine and chlorine in bubbling fluidized bed combustion – Formation of alkali halide aerosols

Fuel ◽  
2014 ◽  
Vol 128 ◽  
pp. 390-395 ◽  
Author(s):  
Hao Wu ◽  
Tor Laurén ◽  
Patrik Yrjas ◽  
Pasi Vainikka ◽  
Mikko Hupa
Keyword(s):  
Fluidized Bed ◽  
Alkali Halide ◽  
Fluidized Bed Combustion ◽  
Bubbling Fluidized Bed

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.

Rice husk bubbling fluidized bed combustion for amorphous silica synthesis

2016 ◽  
Vol 4 (2) ◽  
pp. 2278-2290 ◽  
Author(s):  
Gabriel M. Faé Gomes ◽  
Caterina Philipssen ◽  
Eduardo K. Bard ◽  
Leandro Dalla Zen ◽  
Guilherme de Souza
Keyword(s):  
Fluidized Bed ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Fluidized Bed Combustion ◽  
Bubbling Fluidized Bed ◽  
Silica Synthesis
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