Demineralization of a UK bituminous coal using HF and ferric ions

A UK bituminous coal has been used to study demineralization by two-stage chemical leaching. The first-stage uses hydrofluoric acid (HF) at 65 °C and reduces the ash content from 5.30 wt% to 1.37 wt% by mainly removing Al and Si containing minerals. Subsequent leaching by ferric ions decreases the ash content further to 990 ppm by removing most of the pyrite and fluorides formed during the HF leaching. Calorific value of the coal shows no change following leaching, which suggests no oxidation is occurring to the coal carbonaceous matrix. The mercury and sulfur contents after the two-stage leaching sequence decrease by 40% and 26%, respectively.     

废弃焦粉提纯新工艺研究

针对高灰分焦粉大量废弃堆存的状况, 采用不同浸出剂对高灰分焦粉进行脱灰实验, 确定了碱-酸联合浸出的脱灰工艺, 研究了碱-酸联合浸出脱灰过程温度与脱灰率的关系.使用光谱分析、XRF和化学分析方法, 分析了原料焦粉、碱浸焦粉、碱浸后酸浸焦粉灰分中主要杂质元素铁、铝、钙、硅的存在形态和含量, 探讨了提纯过程的反应机理.焦粉经碱-酸联合浸出后, 灰分由28.6%降至3.85%, 脱灰率达到86.5%.     

脱盐水装置之反渗透系统污堵原因解析

介绍了脱盐水装置反渗透系统生产运行中产生的污堵现象和相关数据;简述了垢样分析和模拟分析的试验结果;分析了反渗透系统污堵的原因;提出了及时对设备反冲洗、控制药剂用量、调整过滤器等技改方案.结果表明,技改后的反渗透系统运行稳定,不仅解决了污堵问题,而且可节省药剂费和耗材费约260万元/a.     

超高压机组供热后的化学水汽品质监督浅析

超高压、汽包炉自然循环机组经设备改造后向外供热,供热后机组的水汽品质与供热前有一定的差异。通过比较机组水汽品质监督数据的差异,分析原因并采取有针对性的措施。通过化学监督管理手段,切实有效地提高了机组的水汽品质。     

煤化学净化的新发展—温和化净化

煤的深度净化需利用化学净化方法，但传统的化学净化方法反应条件苛刻，操作成本十分昂贵，过程的经济性抑制了这些方法的工业化。本文介绍几种该领域最新开发的煤的温和化净化方法，这些新方法的独特性是温和化、高效率、高选择性。有趣的是这些新方法大部分采用有机溶剂抽提煤，溶剂均可通过简单的物理方法加以回收、重新利用。这使得这些新方法在经济上更具吸引力。     

锅炉水质安全与节能

锅炉作为能源消耗大户,其节能、节水十分重要。通过对锅炉水质的软化以及提高蒸汽凝结水的回收率,可收到较好的节能降耗效果,冷凝水回收率在80%时,每年可节约燃料油470t,每年再生剂用量从200t降到140t左右。     

Estimation Method for Exchange Capacity of Mixed Bed Using Monitoring Minicolumns

The methods of estimation of the exchange capacity of mixed bed demineralizer used in nuclear power plants were studied for the purpose of protection against contamination of condensed water with leaked sea water flowing as a coolant in the heat exchanger. It was identified by numerical calculations and experimental works that the performance of mixed bed could be represented by the model for a system of single sort of ion exchange resin and single solute.

The intraparticle diffusivities and ion exchange equilibrium constants for the monitoring minicolumns can be obtained experimentally with the breakthrough curves for different packed height and the equilibrium constant for lm packed height can be known by extrapolation. The constants for 1 m packed height are substituted to the theoretical approximate formula which has been already recognized as a solution for the transient behavior of the adsorption system of a single solute, then the breakthrough time for actually working column of 1 m packed height can be calculated. For the rough estimation of degree of degradation for the deteriorated resin, a simple prediction method was presented in which the relations between the initial concentrations of the effluent from the minicolumns and the packed heights were applied.     

Microwave exposure increases bone demineralization rate independent of temperature

There is a long‐standing controversy regarding an effect of microwaves, independent of increasing temperature, on the rate of bone demineralization. In this study, we exposed standardized samples of gerbil femur to constant microwave exposure while maintaining the demineralizing solution (ethylenediamine tetraacetic acid, EDTA) at 20 °C. Random samples were selected at 3 h intervals, embedded in plastic and sectioned for histological evaluation to determine the extent of demineralization. The time to complete demineralization was significantly faster with microwave exposure (33 h) compared to non‐exposure on a tissue rotator (45 h) in a limited amount (5 mL/24 h) of EDTA. The presence of bone marrow was a significant barrier to the rate of demineralization and resulted in an asymmetrical pattern of mineral extraction. Samples without bone marrow were completely demineralized after 21 h of exposure to microwaves and EDTA. Additional comparisons were made between samples exposed to an effectively infinite supply of demineralizing agent (bone marrow intact). There was a significant increase in rate with unlimited demineralizing agent with (24 h) or without (30 h) microwaves when compared to tissue demineralized on the rotator. Our results establish a positive effect of microwaves on the rate of bone demineralization which is independent of temperature.