The Experimental Study On Lignite Drying And Moisture Absorption

Lignite reserve is abundant in our country, as the moisture content reserve isbigger, immediate using lignite ratio is lower. So it’s necessary to mention quality forlignite, and moisture was removed is particularly important. The advantages offluidized bed drying is obvious in many dry manner. This paper studies the impact ofthree fluidized medias: superheated steam, air, carbon dioxide in fluidized bed dryeron drying and adsorption characteristics of lignite. The results show that particle size,drying temperature, drying rate and drying medium have an influence on drying andadsorption characteristics of lignite. The conclusions are as follows:(1)Study the internal structure and lignite drying mechanism of lignite bytheoretical analysis, master design points of the fluidized bed dryer, and preliminaryunderstand the characteristics of superheated steam, air and carbon dioxide;(2)The lignite is dried by superheated steam, air and carbon dioxide with aself-designed fluidized bed drying device. The results show that: the smaller theparticle size, the higher the drying temperature, the greater the flow rate of the dryingmedium, the faster the drying speed, reversal temperature of steam drying was160℃,When the drying temperature is above160℃，Steam drying temperature is higherthan the other two types of media the air drying speed is higher than the drying speedof carbon dioxide at the same condition;(3) Measured the isothermal moisture at the different drying conditions with aself-designed moisture absorption dynamics experiment device. The results show that:internal pore structure of lignite happened different degree of contraction or collapseafter drying, and it had an influence on adsorption, the higher the drying temperature,the more serious of internal pore structure contraction or collapse, and the more poorof the absorbent capacity after drying. The absorbent capacity have little to do withthe particle size, the smaller of the particle size, the poorer of the absorbent ability. Soelevated temperatures and reduced particle size are good for improve the quality oflignite.