Date of Award
Master of Science (MS)
Formcoke was produced experimentally from a North Dakota lignite and a Wyoming subbituminous coal. The effect of initial charring tem perature (600°C or 900°C), of char grain size (less than 18 mesh, less than 35 mesh, or less than 60 mesh), of briquetting pressure (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or 10,000 psi) of binder percentage (5, 10, 15, 20 or 25 per cent), and of final carbonization heating rate (18°C/:min, 12°C/min or 6°C/min) on formcoke briquet com pressive strength was studied.
A final carbonization heating rate of 6°C/min produced uniform shape briquets. Rates of 12°C/min and 18°C/min resulted in cracked and swollen formcoke briquets produced otherwise under the same condition as the briquets carbonized at 6°C/min.
An increase in the briquetting pressure resulted in an increase in formcoke compressive strength.
Formcoke produced from blends of less than 18 mesh:-900°C-lignite char and 10, 15, or 20 per cent binder exhibited uniform briquet shape. Blends with 5 per cent binder did not hold together once removed from the mold. Blends with 25 per cent binder produced swollen and cracked formcoke after final carbonization.
The 600°C chars produced stronger formcoke than the 900°C chars. Formcoke compressive strength increased with a decrease in char grain size from less than 18 mesh to less than 35 mesh. Formcoke produced from less than 35 mesh char exhibited about the same strength as formcoke produced from less than 60 mesh char.
Petrographically, the 900°C char grains appear more porous than the 600°C char grains. Grain to grain contact of the formcoke was better developed in the formcoke made with 600°C chars than formcoke made with 900°C chars. Grain to grain contact was better developed in formcoke made from 60 mesh char than formcoke made from 35 to 18 mesh char.
Formcoke produced from North Dakota 600°C-lignite char exhibited compressive strengths equal to or greater than compressive strengths of formcoke produced from a Wyoming subbituminous coal. The FMC Corporation has been producing formcoke from Wyoming subbituminous coal, and because formcoke produced experimentally from low temperatures (600°C) lignite char was of equal quality to formcoke produced experimentally from Wyoming subbituminous char, large scale formcoke production from North Dakota lignite may be possible.
Ramsey, Bruce L., "The physical and petrographic characteristics of formcoke produced experimentally from lignite and subbituminous coal" (1974). Theses and Dissertations. 238.