SCI

论文标题    Characterizing moisture occurrence state in coal gasification fine slag filter cake using low field nuclear magnetic resonance technology
作者    Yu, Wei; Wang, Xuebin; Liu, Lijun; Tan, Houzhang; Rahman, Zia Ur
发表/完成日期    2023-08-01
期刊名称    ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
期卷    45
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论文简介    Gasification fine slag, a carbon-rich solid waste produced during coal gasification, is currently disposed of through conventional landfilling methods. Its high-water content hampers resource utilization by reducing its calorific value. This study employs low field nuclear magnetic resonance (LF-NMR) analysis to investigate the water occurrence states in a filter cake with 70.7% moisture content derived from fine gasification slag of the Ningxia coal water slurry furnace. The analysis reveals that free water constitutes a major proportion (68.28%), while combined and capillary water accounts for 2.62% and 2.33%, respectively. The removal of moisture from the coal gasification fine slag filter cake is significantly affected by the drying temperature. The drying rate initially increases and then decreases with different temperatures. For drying temperatures of 60, 70, 80, 90, and 100 degrees C, the maximum drying rates are achieved at 1.09, 1.23, 2.18, 3.86, and 4.01%/min, respectively, with corresponding durations of 40, 40, 25, 30, and 35 min. The T-22 relaxation peak area continually decreases and shifts leftward on the coordinate axis. The behavior of the T-23 and T-22 peaks follows a similar pattern, indicating that water with higher mobility is easily eliminated during drying, while the T-21 peak exhibits a robust signal strength throughout the drying process. At a drying temperature of 100 degrees C, the proportion of free water (A(22)) decreases from 87.3% to 0, the A(23) fluctuates between 0 and 5.3%, and the bound water peak area (A(21)) increases from 10.4% to 94.7% as drying time prolongs. A relationship model is developed between the moisture content of the coal gasification fine slag filter cake and the total integral area of the LF-NMR test, enabling rapid detection and analysis of the total moisture content and distinct occurrence states in the filter cake.