The combustion of pulverised low grade lignite

Bosoaga, A.; Panoiu, N.; Mihăescu, Lucian; Backreedy, R.I.; Ma, Lin; Pourkashanian, Mohamed; Williams, A.

doi:10.1016/j.fuel.2005.12.018

Cited by 51 publications

(16 citation statements)

References 3 publications

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“…Identified major issues such as low burning efficiency and corrosion are associated with the utilization of lignite because of its low calorific value and high proportions of mineral matter and moisture. For example, Bosoaga et al 2 investigated moisture effects on the combustion temperature and pollutant emissions in a 1 MW furnace when burning Romanian lignite. They found the moisture in coal can make the temperature at the furnace center obviously lower and concluded that drying the moist lignite before combustion was required to enhance power plant efficiency.…”

Section: Introductionmentioning

confidence: 99%

Effects of Microwave Irradiation on Combustion and Sodium Release Characteristics of Zhundong Lignite

Wang

Liu

et al. 2016

Energy Fuels

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Lignite can be upgraded by using microwave irradiation (MI), which may change physical and chemical properties of the coal, affecting its combustion characteristics. In this work, MI was used to upgrade coal samples, and the changes in combustion characteristics of the upgraded coal samples were analyzed by thermogravimetric analysis (TGA) and surface temperature measurement. The method of sequential extraction was employed to investigate the changes of various Na classes in different coal samples, and laser-induced breakdown spectroscopy was then used to measure the temporal sodium release during combustion of the different coal samples. Results show that the MI process significantly reduces the moisture concentration, thereby increasing the carbon content and calorific value of the coal. The decrease of the oxygen–carbon atomic ratio indicates an improvement of the coal rank. The TGA shows that the upgrading process will delay the combustion process toward higher temperatures. The comprehensive combustion parameter calculated from the TGA shows the combustion performance of upgraded coal samples became worse, which is also seconded by the measured surface temperatures. MI produces interconversion among different sodium classes, particularly between NH4Ac-soluble sodium and water-soluble sodium. The sodium release characteristics are similar to the surface temperature profiles, indicating that, despite the MI process, sodium release is predominantly controlled by the combustion process. However, the MI process is found to increase both the mass fraction of sodium in coal samples and the amount of sodium release during the combustion process.

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Section: Introductionmentioning

confidence: 99%

Effects of Microwave Irradiation on Combustion and Sodium Release Characteristics of Zhundong Lignite

Wang

Liu

et al. 2016

Energy Fuels

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“…The installation of dry lignite bumers in an existing Greek power plant by replacing the start up oil bumers with dedicated dual bumers firing oil and dry lignite dust could be a next step towards the application of the particular technology in Greek power plants [22,23]. The installation of dry lignite bumers in an existing Greek power plant by replacing the start up oil bumers with dedicated dual bumers firing oil and dry lignite dust could be a next step towards the application of the particular technology in Greek power plants [22,23].…”

Section: Discussionmentioning

confidence: 99%

Investigation of pre-drying lignite in an existing Greek power plant

et al. 2012

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The application of lignite pre-drying technologies in next generation of lignite power plants by utilizing low pressure steam as a drying medium instead of hot recirculated flue gas - combined with thermal utilization of the vaporized coal moisture - is expected to bring efficiency increase of 2-4 percentage points in future lignite power plants compared with today’s state of the art. The pre-drying concept is of particular importance in Greek boilers firing lignite with a high water and ash content. The combustion of Greek predried lignite has been investigated experimentally and via numerical simulations in our previous research. This study focuses on the potential integration of a lignite pre-drying system in an existing Greek power plant with dry lignite co-firing thermal share of up to 30%. The radiative and convective heat fluxes to the boiler and the overall boiler heat balance is calculated for reference and dry lignite co-firing conditions by an in-house calculation code. The overall plant’s thermal cycle is then simulated using commercial thermal cycle calculation software. The net plant efficiency is in this way determined for reference and dry coal co-firing conditions. According to the simulation results the integration of a pre-drying system and the implementation of dry lignite co-firing may bring an efficiency increase of about 1.5 percentage points in existing Greek boilers. It is therefore considered as an important measure towards improving plant efficiency and reducing specific CO2 emissions in existing plants

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“…Results are significantly affected by the choice of CFD model used for pulverized coal combustion simulation, and many researchers report more realistic predictions of flame temperatures using particular models (21)(22)(23)(24)(25). CFD simulations were performed using a pressure-based, steady-state, segregated implicit solver.…”

Section: Cfd Modeling and Experimental Studymentioning

confidence: 99%

The Effect of Temperature Distribution on Tube Rupture

Aydin

Durak

2012

JTST

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This paper reports the effect of temperature distribution on tube rupture at the pulverized coal fired thermal power plant. A computational model was applied to a 150 MWe boiler burning high-ash, medium-volatile coal. The radial and axial flame temperature distribution in the boiler was simulated using CFD code FLUENT. Flame temperatures were measured at points close to wall in some boiler levels and compared with computational fluid dynamics (CFD) solutions. CFD analysis showed that the flame shaped in the centre of the boiler and the temperature decreased gradually towards the boiler walls. The coal and ash composition was analyzed, and tube thickness was measured. Analysis showed that the ash and chlorine content of the coal, and SiO 2 content of the ash were very high. Deposits on tubes can occur overheating, fouling and slagging which lead to tube ruptures. The abrasive effect of the ash accelerated thinning of the tubes and caused them to rupture.

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The combustion of pulverised low grade lignite

Cited by 51 publications

References 3 publications

Effects of Microwave Irradiation on Combustion and Sodium Release Characteristics of Zhundong Lignite

Effects of Microwave Irradiation on Combustion and Sodium Release Characteristics of Zhundong Lignite

Investigation of pre-drying lignite in an existing Greek power plant

The Effect of Temperature Distribution on Tube Rupture

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