毛细柱气相色谱法测定水和废水中的甲醇

讨论了用毛细柱气相色谱法测定水和废水中甲醇的方法 ,该方法用蒸馏前处理样品 ,方法的相对标准偏差为2 .9% ,回收率为 90 .6%～ 97.8% ,最低检出限为 0 .13 ng     

Designing a supercritical steam cycle to integrate the energy requirements of CO2 amine scrubbing

Absorption by chemical solvents combined with CO₂ long-term storage appears to offer interesting and commercial applicable CO₂ capture technology. However one of the main disadvantages is related to the large quantities of heat required to regenerate the amine solvent that means an important power plant efficiency penalty. Different studies have analyzed alternatives to reduce the heat duty on the reboiler and the thermal integration requirements on existing power cycles. In these studies integration principles have been well set up, but there is a lack of information about how to achieve an integrated design and the thermal balances of the modified cycle flowsheet. This paper proposes and provides details about a set of modifications of a supercritical steam cycle to overcome the energy requirements through energetic integration with the aim of reducing the efficiency and power output penalty associated with CO₂ capture process. Modifications include a new designed low-pressure heater flowsheet to take advantage of the CO₂ compression cooling for postcombustion systems and integration of amine reboiler into a steam cycle. It has been carried out several simulations in order to obtain power plant performance depending on sorbent regeneration requirements.     

减压蒸馏耦合微电解处理六硝基二段洗水

通过对六硝基茋(HNS)生产过程中第二段工艺的产品洗涤废水进行水质分析,针对该段废水含有大量吡啶和多种溴代和硝基芳香类化合物的特点,探究了减压蒸馏耦合锌碳微电解法处理二段洗水的效果并优化工艺参数。结果显示,70℃条件下,二段洗水蒸馏至原体积的86.9%时,蒸馏剩余废水TOC去除率为44%,并且此前收集的馏分中吡啶浓度为10%～31.9%(V/V)。减压蒸馏工艺起到收集吡啶同时降低废水TOC的双重作用。减压蒸馏后,残留在废水中的有机物以溴代和硝基芳香化合物为主,采用微电解工艺,其条件优化实验的结果显示,在废水初始pH=1.0,锌投加量为25 g/L,锌碳投加比为1∶1,反应60 min后,废水TOC去除率为33%,采用多级微电解工艺可提高去除效果。     

利用自动蒸馏仪前处理测定地表水中的挥发酚研究

采用瑞士Buchi K-355型自动蒸馏仪对地表水中的挥发酚进行蒸馏预处理,按照(HJ 503-2009)方法分析样品中的挥发酚含量.考察了蒸汽度和蒸馏时间对蒸馏效率的影响.并将该自动蒸馏仪与传统的玻璃蒸馏装置蒸馏检测后的结果进行对比,两者测定结果一致,无显著性差异.利用自动蒸馏仪预处理地表水样品后进行检测,得到的相对标准偏差为4.33%~8.75%,加标回收率为92%~104%,适用于日常环境地表水的监测工作.     

环氧树脂的清洁生产

环氧树脂的生产中,环氧氯丙烷作为一种过量的原料,加以回收时与水一起被蒸馏出来,造成废水中的CODCr达1.0×105mgL,同时酚醛环氧树脂的生产也产生较多的含酚废水。本文介绍了一种环氧树脂清洁生产的新工艺,通过精馏环氧氯丙烷废水和含酚废水,能降低CODCr,回收环氧氯丙烷和苯酚。     

膜蒸馏淡化西部苦咸水应用技术研究

膜蒸馏是将膜与蒸馏过程相结合的分离方法,是一种节能高效的分离技术。本文从其过程机理出发,展望了该技术在苦咸水淡化技术中应用的前景。     

Fluoride removal from brackish groundwater by direct contact membrane distillation

The direct contact membrane distillation applied for fluoride removal from brackish groundwater was investigated.The self-prepared polyvinylidene fluoride membrane exhibited high rejection of inorganic salt solutes.The maximum permeate flux 35.6 kg/(m2 ·hr) was obtained with the feed solution at 80°C and the cold distillate water at 20°C.The feed concentration had no significant impact on the permeate flux and the rejection in fluoride.The precipitation of CaCO3 would clog the hollow fiber inlets and foul the membrane surface with increasing concentration factor when natural groundwater was used directly as the feed,which resulted in a rapid decline in the module efficiency.This phenomenon was diminished by acidification of the feed.The experimental results showed that the permeate flux and the quality of obtained distillate kept stable before concentration factor reached 5.0 with the acidified groundwater as feed.The membrane module efficiency began to decline gradually when the feed continued to be concentrated,which can be mainly attributed to the formation of CaF2 deposits on the membrane surface.In addition,a 300 hr continuous fluoride removal experiment of acidified groundwater was carried out with concentration factor at 4.0,the permeate flux kept stable and the permeate fluoride was not detected.     

膜蒸馏技术在环保领域中的应用

膜蒸馏是一种以蒸汽压差为推动力的新型分离技术,本文综述了膜蒸馏技术的原理、优点及其分类。分析了该技术在环保领域的应用,指出了膜蒸馏技术的应用前景。     

海水中挥发酚的在线蒸馏-流动注射分析

采用流动注射分析仪测定渔业养殖海水中的挥发酚.方法的检出限为0.89μg/L;线性范围为0.002～0.1 mg/L,线性相关系数r≥0.999;其相对标准偏差为1%～5%,样品测定频率为18样/h.本方法操作简便、灵敏度较高,线性范围、精密度和准确度均符合国家标准.对海水水样加标回收率的测定为90%～110%,结果令...     

Combining steam injection with hydraulic fracturing for the in situ remediation of the unsaturated zone of a fractured soil polluted by jet fuel

A steam injection pilot-scale experiment was performed on the unsaturated zone of a strongly heterogeneous fractured soil contaminated by jet fuel. Before the treatment, the soil was stimulated by creating sub-horizontal sand-filled hydraulic fractures at three depths. The steam was injected through one hydraulic fracture and gas/water/non-aqueous phase liquid (NAPL) was extracted from the remaining fractures by applying a vacuum to extraction wells. The injection strategy was designed to maximize the heat delivery over the entire cell (10 m × 10 m × 5 m). The soil temperature profile, the recovered NAPL, the extracted water, and the concentrations of volatile organic compounds (VOCs) in the gas phase were monitored during the field test. GC-MS chemical analyses of pre- and post-treatment soil samples allowed for the quantitative assessment of the remediation efficiency. The growth of the heat front followed the configuration of hydraulic fractures. The average concentration of total hydrocarbons (g/kg of soil) was reduced by ～ 43% in the upper target zone (depth = 1.5-3.9 m) and by ～ 72% over the entire zone (depth = 1.5-5.5 m). The total NAPL mass removal based on gas and liquid stream measurements and the free-NAPL product were almost 30% and 2%, respectively, of those estimated from chemical analyses of pre- and post-treatment soil samples. The dominant mechanisms of soil remediation was the vaporization of jet fuel compounds at temperatures lower than their normal boiling points (steam distillation) enhanced by the ventilation of porous matrix due to the forced convective flow of air. In addition, the significant reduction of the NAPL mass in the less-heated deeper zone may be attributed to the counter-current imbibition of condensed water from natural fractures into the porous matrix and the gravity drainage associated with seasonal fluctuations of the water table.