Coal Ash Fusion Temperatures — New Characterisation Techniques, and Associations with Phase Equilibria

Wall, Terry; Creelman, Robert A.; Gupta, Rajender; Gupta, Sushil K.; Coin, C.; Lowe, A.

doi:10.1007/978-1-4757-9223-2_36

Cited by 12 publications

(5 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further, strict control and observance of the test conditions is necessary to obtain reproducible results. Both repeatability and reproducibility have recently been shown to be poor in other ash fusion standards. , In one investigation, the reproducibility has been demonstrated to be as poor as 140 °C. However, in the used method (ISO-540) the height and the width are continuously measured online and a reproducibility of ±5 °C has been reported in the standard…”

Section: Discussionmentioning

confidence: 99%

Predicting Slagging Tendencies for Biomass Pellets Fired in Residential Appliances: A Comparison of Different Prediction Methods

et al. 2008

View full text Add to dashboard Cite

In this paper, a comparison between four different types (both empirical and theoretical) of techniques to predict the slagging tendencies in residential pellet combustion appliances was performed. The four techniques used were the standard ash fusion test (SS ISO-540) used in the Swedish pellet standard (SS 18 71 20), thermal analysis (TGA/DTA), thermochemical model calculations, and a laboratory-scale sintering test. The tests were performed with 12 pelletized biomass raw materials, and the results were compared with measured slagging tendencies in controlled combustion experiments in a commercial under-fed pellet burner (20 kW) installed in a reference boiler. The results showed significant differences in the prediction of slagging tendencies between different predicting techniques and fuels. The method based on thermal analysis (TGA/DTA) of produced slags must be further developed before useful information could be provided of the slagging behavior of different fuels. The used sintering method must also be further improved before the slagging tendency of fuels forming slags extremely rich in silicon (e.g., some grasses) can be predicted. Relatively good agreement was obtained between results from chemical equilibrium calculations and the actual slagging tendencies from the combustion tests. However, the model calculations must be further improved before quantitative results can be used. The results from the standard ash fusion test (SS ISO 540) showed, in general, relatively high deformation temperatures, therefore predicting a less problematic behavior of the fuels in comparison to the actual slagging tendencies obtained from controlled combustion experiments in commercial pellet burner equipment. Nevertheless, the method predicted, in most cases, the same fuel-specific slagging (qualitatively) trends as the corresponding combustion behavior.

show abstract

Section: Discussionmentioning

confidence: 99%

Predicting Slagging Tendencies for Biomass Pellets Fired in Residential Appliances: A Comparison of Different Prediction Methods

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Ash fusion tests based on the norm ISO 540 (2008) or equivalent norms have been widely utilized for coal ashes . Their performance for the prediction of slagging risk in the combustion of biomass fuels, nevertheless, has been widely criticized in the literature in terms of lack of representativity of the small ash sample utilized, the low representativity of the ashing temperature utilized to generate the ash sample test and the temperature ramp and atmosphere conditions of the test, and the risk of boiler slag formation not being detected because of the changes in the shape of the small ash sample utilized in the test. − Reports of low correlation of the ash fusion test results with the biomass slagging observed under the boiler combustion conditions are frequent, with many reported cases of underestimation by the test of the slagging observed in the boiler, resulting in a need for the development of more reliable new ash slagging methods. − …”

Section: Introductionmentioning

confidence: 99%

Measuring and Predicting the Slagging of Woody and Herbaceous Mediterranean Biomass Fuels on a Domestic Pellet Boiler

Vega-Nieva¹,

Ortiz²,

Tabarés³

et al. 2016

Energy Fuels

View full text Add to dashboard Cite

One of the main barriers for the successful utilization of new biomass feedstocks in commercial pellet boilers is the lack of knowledge about the combustion behavior of such fuels, particularly in terms of ash slagging, which can potentially damage the boiler and limit combustion efficiency. The VI Framework European project Domoheat studied the combustion of 15 Mediterranean woody and herbaceous biomass fuels in commercial 60 kW domestic pellet boilers. The performance of several methods for the prediction of measured boiler slagging was tested, including ash composition-based slagging indices, standard ash initial deformation temperature (IDT), and a new slagging laboratory method, the BioSlag test, based on the sieving of the ash and slag obtained in the combustion of 250 g of fuel in a furnace at controlled temperature conditions. IDT values allowed us to identify slagging in fuels with high silica (e.g., rye straw pellet) or alkali contents (e.g., almond shell) but failed to discriminate medium slagging of fuels such as contaminated poplar chip. Slagging indices based on silica and alkali content of the ashes showed success for predicting boiler-observed slagging. The BioSlag test predicted observed slagging percentage in the boiler with R 2 = 0.87. This test could discriminate both high slagging of fuels with high Si content (e.g., rye straw pellet, pinecone seed shell) and the medium slagging tendency caused by alkali elements (e.g., almond shell, olive stone) and by moderate Si contents (e.g., contaminated poplar chip).

show abstract

“…Several methods have been reported for the prediction of ash behavior during combustion. Agglomeration tendency of ash has been studied by use of ash fusion, − compression strength sintering, , and lab-scale FB combustion tests …”

Section: Introductionmentioning

confidence: 99%

The Role of Amorphous Material in Ash on the Agglomeration Problems in FB Boilers. A Powder XRD and SEM-EDS Study

2002

View full text Add to dashboard Cite

Bed agglomeration is one of the most common problems in FB boilers. In this work the dependence of agglomeration tendency of peat and biomass ash on the content of amorphous material in ash has been investigated. The factors affecting the interactions between quartz bed particles and ash-forming elements have been modeled by involving mixtures of oxides that are commonly found in ash by utilizing X-ray powder diffraction for a semiquantitative determination of amorphous phases and SEM-EDS for compositional distributions. It is well-known that high iron or alkali metal contents increase the agglomeration tendency of ash. It can indeed be seen that the amount of amorphous material in ash increases with increasing iron or alkali metal contents. The results have been compared with those of two standard peat ashes, one of which is known to be unproblematic, while severe agglomeration has been observed in the case of the other.

show abstract

Coal Ash Fusion Temperatures — New Characterisation Techniques, and Associations with Phase Equilibria

Cited by 12 publications

References 2 publications

Predicting Slagging Tendencies for Biomass Pellets Fired in Residential Appliances: A Comparison of Different Prediction Methods

Predicting Slagging Tendencies for Biomass Pellets Fired in Residential Appliances: A Comparison of Different Prediction Methods

Measuring and Predicting the Slagging of Woody and Herbaceous Mediterranean Biomass Fuels on a Domestic Pellet Boiler

The Role of Amorphous Material in Ash on the Agglomeration Problems in FB Boilers. A Powder XRD and SEM-EDS Study

Contact Info

Product

Resources

About