Study on drying characteristics with low temperature of different particle size semi-coke

In order to reduce the transportation cost of the semi-coke and improve the combustion efficiency,scanning electron microscopy(SEM),N2 adsorption-desorption and X-ray photoelectron spectroscopy(XPS)analysis were used to study the surface structure of Shenmu semi-coke,and the drying and dehydration on different sizes of semi-coke was studied by air-blast drying.The results show that the pores of semi-coke are developed,but the oxygen functional groups of the semi-coke are obviously reduced compared with the raw coal,and the moisture of the semi-coke is mostly physically adsorbed in the pores,and the moisture can be evaporated fully by air-blast drying.What’s more,the higher the drying temperature,the faster the water loss rate of the same particle size semi-coke,and the shorter the drying time.When the drying temperature is less than 200 ℃,the dehydration rate is fine grain > small-sized grain > medium grain;when drying temperature is 250 ℃,the moisture loss is in the order of fine grain>middle grain>small grain,and when the drying temperature is more than 300 ℃,the three-grained semi-coke water loss rate is close to each other,and the total drying time is 50 min.Therefore,the drying temperature should be 200～250 ℃.After drying,the dried semi-coke will have 1.0%～1.6% moisture absorption,the whole moisture content will be controlled at about 2.0%.