Investigating Compatible Drying Technique for Safe Utilization of Thar Coal, Pakistan

ABSTRACT

To enhance the combustion efficiency of high moist coal, it is important to reduce its moisture contents. For reduction of moisture contents, the selection of efficient and low-cost drying technique based on the coal characteristics is helpful to convert the high moist coal to good quality fuel. A total of 18 Thar coal (Pakistan) samples were crushed and sieved at following size fractions (355, 500, 710 µm). These samples were dried using different techniques, namely, solar-drying, hot air-drying, oven-drying, microwave oven-drying, and flue gases drying. The morphological, physical, and chemical changes were investigated for the effectiveness of different techniques to make the Thar coal as a value-added fuel. The applied drying techniques showed a significant reduction in moisture contents from the Thar coal samples (38.11 to 7.78%). However, the flue gases drying and air-drying techniques showed highest reduction in moisture content (29–31%). Similarly, 35% increase in heating value (HV) J/kg was observed in case of flue gases drying technique. These results indicated that the flue gases and air-drying techniques may be used to reduce the moisture contents and enhance the HV of high moist Thar coal that can be used as value-added fuel in the country.

KEYWORDS:

• Thar coal
• moisture contents
• drying techniques
• combustion efficiency