Ash melting behavior by Fourier transform infrared spectroscopy

A Fourier Transform Infrared Spectroscopic(FTIR)method involving a Fe2O3 flux was used to learn how China's coal ash melts.The relationship between ash fusion temperature and chemical composition,as well as the effects of Fe2O3 flux on the ash fusion temperature were studied.The relationship between ash fusion temperature and chemical composition,mineralogical phases and functional groups was analyzed with the FTIR method.The results show that the ash fusion temperature is related to the location and transmittance of certain absorption peaks,which is of great significance for the study of ash behavior.

Influence of Ca(OH)_(2) on ash melting behaviour of woody biomass

Woody biomass is a renewable source offering high potential for production of bio-fuels,-chemicals and-energy.During the outdoor storage of biomass biodegradation processes take place,which leads to mass reduction up to 30 wt%.To avoid these mass losses,the biomass was mixed with Ca(OH)_(2) in different ratios.To ensure,that this additive does not negatively influence further thermo-chemical conversion of biomass(e.g.by fluidized bed combustion),the spruce and poplar ash with and without additive was tested using ash melting microscopy.It was demonstrated that all the characteristic temperatures(DT,HT,FT)were significantly higher than the thermo-chemical conversion process temperatures in a fluidized bed.Thus it could be pointed out that the addition of Ca(OH)_(2) does not negatively influence ash melting behaviour,ash melting temperature respectively.

The Mineral Transformation of Huainan Coal Ashes in Reducing Atmospheres

By using the advanced instrumentation of a Computer Controlled Scanning Electron Microscope （CCSEM）, X-ray diffraction （XRD） and X-ray fluorescence （XRF）, the ash composition and the mineral components of six typical Huainan coals of different origins were studied. The transformation of mineral matter at high temperatures was tracked by XRD in reducing conditions. The quartz phase decreased sharply and the anorthite content tended to increase at first and then decreased with increasing temperatures. The formed mullite phase reached a maximum at 1250 ℃ but showed a tendency of slow decline when the temperature was over 1250 ℃. The mullite formed in the heating process was the main reason of the high ash melting temperature of Huainan coals. Differences in peak intensity of mullite and anorthite reflected differences in phase concentration of the quenched slag fractions, which contributed to the differences in ash melting temperatures. The differences in the location of an mnorphous hump maximum indicated differences of glass types which may affect ash melting temperatures. For Huainan coal samples with relatively high ash melting tempera- tures, the intensity of the diffraction lines for mullite under reducing condition is high while for the samples with relatively low ash melting temperature the intensity for anorthite is high.

Effect of refractory agent on ash fusibility temperatures of briquettet

To solve the problem of the low ash fusion point of briquette, this paper reported that the ash fusibility temperatures can be elevated by changing ash ingredients through blending refractory agents in briquette ash, which will create favorable conditions for moving bed continuous gasification of briquette with oxygen-rich air. The effects of A1203, SiO2, kaolin, dry powder and bentonite on ash fusibility temperatures were studied, based upon the relationship between briquette ash components and ash fusibility. The results show that the increasing of ash fusibility temperatures by adding the same amount （11%, w） of refractory agents follows the sequence of SiO2, bentonite, dry powder, kaolin, A1203, with the softening temperatures being elevated by 37.2, 57.6, 60.4, 82.6 and 104.4℃. With the same ratio of SIO2/A1203 in briquette, adding the A1203 component is more effective than SiO2 for raising ash fusibility temperatures. In this paper, inexpensive kaolin and bentonite rich in A1203 are found to be better refractory agents, and the suitable adding quantities are 9% and 11%, respectively.

Study on the characteristics of mineral matter in Huainan coals by computer controlled scanning electron microscope (CCSEM)

The mineral features, ash composition, ash fusion temperature of Huainan coals were investigated by CCSEM, X-ray fluorescence (XRF) and JIS (Japan Industrial Standard) ash cone melting method respectively. The mineral matter is characterized by higher aluminosilicate clay minerals contents (more than 60% of the total mineral matter in coal) with quartz, which accounts for the higher ash flow temperatures, frequently higher than1 500℃. The contents of calcite and dolomite in Huainan coals range from 0.16% to about 11.57%. Another important non-silicate mineral matter, pyrite, ranges from 0.73% to 12.25%. Low amount of kaolinite-type clays and high amount of calcite and pyrite in the HN115 and XM coals are beneficial to ash melting. It is suggested that the high content of kaolinite in Huainan coals shows the high ash fusion temperature. CCSEM results also provide the size distribution of the minerals in Huainan coals. Generally, the mineral has bimodal size distribution in 6 Huainan coals.