Energy consumption during dewatering process affected by carboxyl on coal surface

ABSTRACT

The energy consumption during dewatering and carboxyl concentrations on the surfaces of six different coals were examined. Three stages of dewatering were investigated based on the energy consumption. The water in the spaces between coal particles and large pores, water in progressively smaller capillaries and pores, water clusters around the functional groups, and water directly absorbed by oxygen functional groups were subsequently removed with increasing energy consumption. The moisture present in three forms was significantly affected by carboxyl concentrations. In the first and second stages, the energy consumption at the same residual moisture content was closely related to the carboxyl concentrations. Even at the same ratio of moisture content to carboxyl concentration, energy consumption increased with an increase in carboxyl concentration on coal surface in the second stage.

KEYWORDS:

• Carbonyl
• dewatering
• differential scanning calorimetry (DSC)
• energy consumption
• thermogravimetry (TG) analysis