褐煤弱氧化改质脱水水质对比分析

Analysis of water quality after lignite weak oxidation and thermal upgrading at low temperature

为实现褐煤提质并解决褐煤主产地干旱缺水问题,采用自行设计的固定床反应器及电感耦合等离子体质谱（ICP-MS）对锡林郭勒褐煤进行不同干燥介质脱水并对冷凝水水质进行对比分析,同时对不同干燥温度下的煤样在干燥过程中产生的气体产率也进行了研究。结果表明：两种不同粒径煤样随着干燥时间延长,煤样含水率逐渐降低,且脱水温度越高,含水率越低。相同干燥条件下,0.5～0mm煤样冷凝水中COD、BOD、NH3-N和TON值略大于6～3mm煤样。四种重金属离子的析出量均随着脱水温度的升高而逐渐增大,但煤样干燥冷凝水中重金属离子含量远低于地表水环境质量V类标准基本项目标准限值。氧气作为干燥介质时,CO2和CO的产生除了煤样自身发生分解之外,另一部分CO2和CO的产生来自煤样在干燥过程中发生的弱氧化反应。

In order to achieve lignite upgrading and solve the problem of drought and water shortage in main producing area of lignite, the water quality of condensed water with different drying media were carried out with a fixed bed reactor and an inductively coupled plasma mass spectrometry. The gas production rate of coal samples under different drying temperature was also analyzed. The resttlts indicate that two different particle size of coal samples with extended drying time, moisture content of coal sample reduced gradually, and dehydration temperature is higher, the lower the moisture content. The values of COD, BOD, NH3-N and TON in condensate water produced from dry coal sample with particle size of 0. 5 to 0 mm are slightly larger than the 6~ 3mm samples under the same drying conditions. As the dehydration temperature rises, the four kinds of heavy metal ions precipitation amount in condensate water increase gradually. However, the content of heavy metal ions in the condensate water is much lower than that of the surface water environment quality standard V. When oxygen is used as a drying medium, the CO2 and CO are produced in addition to the decomposition of the coal sample itself, and the other part of CO2 and CO are produced from the weak oxidation reaction of coal samples during the drying process.