Investigation of drying characteristics of low rank coal of bubbling fluidization through experiment using lab scale

Abstract

Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utilize it in power plant. In the present work, experiments on lignite has been done using a lab scale fluidized-bed reactor. Drying lignite through fluidized-bed reactor has a higher drying rate because there is good contact between particles and gas in the fluidized-bed reactor. Fluidized-bed drying can use air of 1.5 times of the minimum fluidizing velocity performance at bubbling fluidized-bed. Experiments have been performed on coal particle sizes of 0.3-1 mm, 1-1.18 mm and 1.18-2.8 mm, with operating temperatures being 100°C, 125°C and 150°C, respectively. It is found that fluidization has a higher drying rate due to the heat transfer rate through air velocity. Hence, moisture content in lignite can be dried to a desired value with a time interval of 10 min. The experiment through fluidized-bed reactor is expected to be useful for saving money and time. low rank coal, moisture content, minimum fluidizing velocity, bubbling fluidized-bed Citation: Jeon D M, Kang T J, Kim H T, et al. Investigation of drying characteristics of low rank coal of bubbling fluidization through experiment using lab scale.

Effects of Bed Height and Particle Size on Drying of a Turkish Lignite

“…3 Turn on the system again and start the experiment. Every 10 minutes, take a lignite sample from the upper side of the bed and load them into crucibles.…”

“…Due to the different particle sizes and the nature of lignite, initial moisture content varied. For this reason, in the drying analyses, a moisture ratio value was used, and it was calculated using Equation 3:…”

“…This situation lets people find effective and cleaner ways to utilize fossil fuels. Lignite constitutes nearly half of the coal reserves of the world [3][4]. Lignite, which is a cheap energy source has high-moisture content (up to 65%, wet basis) that limits its usability [5][6].…”

Recent advances in beneficiation for low rank coals

“…Drying and cleaning prior to the use of lignite are urgently required. Drying low rank coals before burning is an effective method to save energy and improve energy efficiency [7,8]. Meanwhile, the transport of low rank coals will be saved after upgrading processes [9].…”

Drying kinetics of coarse lignite particles in a fixed bed

“…Lignite constitutes about 45% of the total coal reserves and are distributed throughout the world [3]. Low Rank Coals (LRCs) including brown and subbituminous coals, which are known as having high moisture content (up to 65%, wet basis), are very important for LRC fired power plants, gasification and liquefaction [4].…”