Laboratory of Inorganic Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia.
J Hazard Mater. 2010 Feb 15;174(1-3):209-14. doi: 10.1016/j.jhazmat.2009.09.038. Epub 2009 Sep 16.
Solid waste and atmospheric emissions originating from power production are serious problems worldwide. In the Republic of Estonia, the energy sector is predominantly based on combustion of a low-grade carbonaceous fossil fuel: Estonian oil shale. Depending on the combustion technology, oil shale ash contains 10-25% free lime. To transport the ash to wet open-air deposits, a hydraulic system is used in which 10(7)-10(8) cubic meters of Ca(2+)-ion-saturated alkaline water (pH level 12-13) is recycled between the plant and sedimentation ponds. The goals of the current work were to design an ash-water suspension carbonation process in a continuous mode laboratory-scale plant and to search for potential means of intensifying the water neutralization process. The carbonation process was optimized by cascading reactor columns in which the pH progressed from alkaline to almost neutral. The amount of CO(2) captured from flue gases can reach 1-1.2 million ton at the 2007 production level of the SC Narva Power Plants. Laboratory-scale neutralization experiments were carried out to compare two reactor designs. Sedimentation of PCC particles of rhombohedral crystalline structure was demonstrated and their main characteristics were determined. A new method providing 50x greater specific intensity is also discussed.
固体废物和大气排放物源自发电是全世界的严重问题。在爱沙尼亚共和国，能源部门主要依赖于燃烧一种低品位的含碳化石燃料：爱沙尼亚油页岩。根据燃烧技术的不同，油页岩灰中含有 10-25%的游离石灰。为了将灰运送到湿式露天矿床，使用了一种水力系统，其中在工厂和沉淀池之间循环使用 10(7)-10(8)立方米 Ca(2+)-离子饱和碱性水（pH 值为 12-13）。目前工作的目标是在连续模式的实验室规模工厂中设计灰水碳酸化工艺，并寻找强化水中和过程的潜在方法。碳酸化过程通过级联反应器柱进行优化，其中 pH 值从碱性逐渐变为接近中性。以 2007 年 SC Narva 发电厂的产量计算，从烟道气中捕获的 CO(2)量可达 100 万至 120 万吨。进行了实验室规模的中和实验，以比较两种反应器设计。证明了菱面体结晶结构的 PCC 颗粒的沉淀，并确定了它们的主要特征。还讨论了一种提供 50 倍更高比强度的新方法。
