The effect of bituminous additives on the carbonization of oxidized coals

Abstract

Two bituminous coals of different rank and coking characteristics were oxidized at low temperature for two months. Bituminous additives obtained in-situ in the coking plant were used to improve the thermoplastic properties of the oxidized coals. The Gieseler fluidity test was applied to evaluate their coking properties. A thermogravimetric analysis (TGA) of the fresh, oxidized coals and their blends with the bituminous additives was carried in order to evaluate the interaction between the blend components.In addition, carbonization tests of the fresh and oxidized coals and the blends with the additives were carried out in a movable wall oven of 17 kg capacity and the quality of the cokes tested by means of standardized methods generally used by the steel industry.The additives increased coal fluidity but the original fluidity values could not be recovered. From TGA it was concluded that the blend components behave independently of one another during co-carbonization. The oxidation of coal leads to an increase in the dangerousness of the low volatile coal which was related to the porous texture of the cokes. In addition, it was found that the decrease in the quality of the coke produced from low rank oxidized coal can be partially recovered by using bituminous additives.

Comparative Characterization of a Torrefied Wood Pellet under Steam and Nitrogen Atmospheres

“…Figure shows the van Krevelen diagram of the C, H, and O composition of various coals (anthracite, sub-bituminous, bituminous, and lignite), raw wood pellets, and TWP. − The origin (zero point) of the graph represents pure carbon. In the initial torrefaction at 230 °C, the −OH group that can relatively easily break down from the biomass structures is decomposed; hence, the carbon content slightly increases.…”

“…Van Krevelen diagram from C, H, and O of various coals and TWP (a, data taken form Jiang et al, 2016; b, data taken form Vega et al, 2017; c, data taken form Burmistrz et al, 2016).…”

The Influence of Coal Tar Pitches on Thermal Behaviour of a High-Volatile Bituminous Polish Coal

“…The research conducted by Nomura and Arima [3] proved that the addition of a coalderived binder can reduce the yield of volatile products from the blend during pyrolysis at the temperature below 450 • C. Coal tar and coal tar pitch (CTP) have been known for a long time as additives that improve the fluidity of coals [4][5][6][7][8] and their caking properties [3,4]. The authors of the works [9,10] suggest that pitch additives can be used as additives that bring back the lost thermoplastic abilities to low-oxidized coals. These additives can be used as binders for briquettes with coals having worse caking properties [11][12][13][14].…”

“…It is believed that the decomposition products of CTP interact with coal and increase its thermoplasticity this way [3,20]. As a result of such interaction, an Materials 2022, 15, 9027 2 of 20 increase in the coking pressure of coal blends with pitch can take place [10,[21][22][23]. Duffy et al [15] determined an increase in the coking pressure as a result of the addition of pitch to a coal of higher fluidity.…”

The effect of briquette composition on coking pressure generation

“…The effect of additives on coking pressure depends on their characteristics. Thus coke fines, sawdust and anthracite tend to reduce coking pressure whereas bituminous additives increase it [13][14][15]. In light of this, the study of the effect of briquettes prepared with coal tar as binder and sawdust is interesting considering the effects of these briquette components on the development of coking pressure.…”