Improving the properties of high volatile coking coals by controlled mild oxidation

Abstract

Four bituminous coals of the same rank but with different thermoplastic properties were oxidized at 40 and 50 ºC for one month. The chemical changes due to oxidation were studied by applying Gieseler plastometry, the free-swelling index (FSI), thermogravimetric analysis and Fourier transform infrared spectroscopy (FTIR). In general, oxidation at 50 ºC produced a greater impairment of coking properties, the different responses to oxidation depending on the parent coal. The main effects caused by oxidation were a loss of thermoplastic properties, a decrease in aliphatic hydrogen and a slight increase in groups with oxygen functionalities.Both the fresh and oxidized coals were carbonized in a movable-wall oven of 17 kg capacity and the quality of the resulting cokes was tested by means of the ASTM standard method. The results showed that, in certain cases, mild oxidation produced an improvement in coke quality. Oxidation also affected the porosity of the cokes, which may be related to the coke quality. It was found that the higher quality cokes had less macroporosity, whereas the lower quality cokes had a higher pore volume.

The relation between CRI, CSR indexes, chemical composition and physical parameters of commercial metallurgical cokes

“…The pycnometer density is determined in a similar way to true density: however, the sample analysed is not pulverised. The values of pycnometer density varied from 1729.3 to 1903.1 kg m −3 and were comparable to those obtained by Vega et al [32] by applying a helium pycnometer.…”

Effective Utilization Technique for Coal Having High Maximum Fluidity and Long Maximum Permeation Distance by Weathering Processing

“…8) On the contrary, it was reported that coking property of coal having high caking properties can be improved by proper weathering and deterioration of caking property because the coal with excessive caking properties tends to becomes fragile coke with highly porous structure. [9][10][11][12] For example, Vega et al 12) investigated that the changes of properties of coal after weathering processing and coke derived from processed coal. In that paper, 4 high MF coals were processed in dryer machine at 40 or 50 degrees Celsius with the air atmosphere within 40 days.…”

Kualitas Batubara Formasi Tanjung Di Daerah Sekako, Kalimantan Tengah

“…Kandungan zat tebang yang sangat tinggi memiliki kandungan hidrogen dan rasio H/C yang relatif tinggi [1,3,25]. Hal tersebut akan menyebabkan batubara akan lebih bersifat reactive sehingga akan menyebabkan maksimum fluiditas yang tinggi [26,27]. Untuk itu harus diperlukan suatu proses agar syarat sebagai batubara coking dapat sepenuhnya terpenuhi, misalnya dengan proses blending.…”