Utilization of Low-rank Brown Coals with Pollution Control

本课题主要做了以下几个方面的研究工作：(1)含钙煤去除废水中的重金属研究了两种褐煤、氧化腐殖石和泥炭对废水中重金属的去除能力。结果表明，这些材料负载的钙可以通过与钙的离子交换有效地用于重金属的提取。所研究的材料对给定的金属具有类似的选择性。但从实用的角度来看，可推荐使用含钙煤：含钙煤与溶液接触时会部分解体，泥炭的利用在经济上不太有利。建议将建议的方法用于金属浓度小于10 mm的地方。(2)循环流化床锅炉的灰渣作为道路基层材料的利用由于废物管理法规的加强，处理沸腾床燃烧灰渣的难度越来越大，因此成本也越来越高。如果能将沸腾燃烧产生的灰分加工成道路基层材料，这将是非常有用的。因此，开发了一种简单、低成本的道路基层材料生产工艺，即将灰分与水混合，模压、蒸煮、陈化并粉碎成小块。讨论了获得最佳产品所需的条件和铺路试验结果。(3)低阶煤的超临界水液化利用半间歇微反装置对低阶煤的超临界水液化进行了研究。在不到7min的时间内，液体产率达到41wt%。残渣随后发生气化反应。^2D-n.m.r.超临界液体产物的光谱分析和质量平衡结果表明，煤的超临界水液化过程中，水解反应和缩合反应都有助于脱氧。

In this project, the following researches have been done.(1) Removal of Heavy Metals from Waste Waters by Calcium-loaded CoalTwo types of brown coal, oxyhumolite and peat were studied with respect to their ability to remove heavy metals from waste water. The results showed that the calcium loaded from these materials can be effectively used for heavy metal extraction by ion exchange with calcium. The studied materials have a similar selectivity for a given metal. From the practical point of view, however, the calcium-loaded coal can be recommended : oxyhumolite partially disintegrated in the contact with the solution and the utilization of peat is economically less favorable. The proposed method can be recommended for concentrations of metals less than 10 mM.(2) Utilization of Coal Ash from FBC Boilers as Road Base MaterialThe disposal of fluidized-bed combustion ash is increasingly difficult, and therefore costlier, because of tighter legislation on waste management. It would be useful if ash from fluidized-bed combustion could be processed into road base material. A simple and low-cost road base material production process has, therefore, been developed where the ash is mixed with water, molded, steamed, aged and crushed into small pieces. The conditions required to yield optimum products and the paving test results were discussed.(3) Liquefaction of Low-Rank Coal using Supercritical WaterThe liquefaction of low-rank coal with supercritical water has been studied using a semi-batch microreactor. Liquids yield to 41wt% is attained in less than 7 min. Subsequent gasification of residue takes place. ^2D-n.m.r. spectral analysis of liquids products in supercritical and the results of mass balance suggests that both hydrolysis and condensation reactions contribute to oxygen removal during supercritical water liquefaction of coal.