超临界流体萃取法

介绍了超临界流体的性质：超临界流体萃取法的原理，特点及应用。讨论了应用超临界流体萃取进行样品预处理的条件选择：超临界流体的选择，列举了数种常用的超临界流体，详尽介绍了ＣＯ２的特性及其在样品预处理中的应用范围；萃取条件选择的预测方法，试验方法，萃取压力的选择，， 同类别物质的以，不联机及联机的收集技术等。     

超临界流体色谱分析有机污染物

概述了超临界流体色谱的进展，特点、原理及影响超临界流体色谱测定的主要因素。介绍了超临界流体色谱与其他测定仪器的联用技术。列举了该技术在分析环境样品中有机污染物的应用。如分析有机氯、有机磷和氨基酸酯及农药的残留组分，多环芳烃，芳香烃等化合物。     

超临界CO2处理含氰废水初步研究

超临界ＣＯ２能萃取出含氰废水中的ＣＮ＾－，萃取物在压力降低时释放出来，释放物用饱和ＦｅＣｌ２溶液吸收稳定。萃取的最佳条件是：压力为１０ＭＰａ－１５ＭＰａ，温度为３０－５０℃，时间为２０ｍｉｎ－３０ｍｉｎ。     

超临界水氧化处理分散染料废水中含氮有机物的实验研究

采用H2O2为氧化剂,在连续蒸发壁式反应器中进行了超临界水氧化降解分散染料废水的实验.结果表明:超临界水氧化技术处理分散染料废水时,TOC的去除效果优于TN的去除效果.在25 MPa,380～460℃的条件下,短短30s的时间内,TOC去除率可达到90%以上,而TN去除率却只有45%～60%.随着温度和压力的升高以及氧化剂用量的增加,废水中TN浓度随之下降而NH3-N浓度却随之升高.     

超临界CO2和液态CO2及气态N2注入采空区防灭火性能实验

为对比研究超临界态CO_2、液态CO_2和气态N_2注入采空区的防灭火性能,自主研制了模拟采空区残煤自燃过程实验系统,开展了超临界态CO_2、液态CO_2和气态N_2注入采空区防灭火实验。实验结果表明:12 MPa、39℃超临界态CO_2对采空区自燃残煤的降氧降温能力优于6 MPa、30℃液态CO_2优于6 MPa、39℃气态N_2;12 MPa、39℃超临界态CO_2对残煤的降温能力是6 MPa、30℃液态CO_2的1.7倍,是6 MPa、39℃气态N_2的10倍,对采空区的降温能力是液态CO_2的2倍,为气态N_2的8倍;12 MPa、39℃超临界CO_2对采空区的降氧速率比6 MPa、30℃液态CO_2和6 MPa、39℃气态N_2高12.5%;12 MPa、39℃超临界CO_2的降温能力是8 MPa、39℃超临界CO_2的1.7倍,因此适当提高超临界态CO_2的注入压力,防灭火性能更佳。     

Lessons learned from a supercritical pressure BLEVE in Nihon Dempa Kogyo Crystal Inc.

On December 7, 2009, a 50-foot-tall high-pressure vessel ruptured in the Nihon Dempa Kogyo Crystal, Inc. facility in Belvidere, Illinois. Several projectiles rapidly traveled outward from the facility, killing a truck driver 650 feet away and injuring an employee in another building 435 feet away. This paper summarizes the lessons learned from this incident both on causal and consequential aspects. Stress corrosion cracking was identified as the failure mechanism by the U.S. Chemical Safety and Hazard Investigation Board. After analyzing the operating conditions and the aftermath, this incident has been identified as a Boiling Liquid Expanding Vapor Explosion (BLEVE) under a supercritical pressure. A consequence analysis of the incident is performed where overpressure and fragment distance are calculated, together with safety distance estimation. Additionally, other safety-related problems, such as safety culture, management inside the corporation, and communication between this facility and the government are discussed.     

Experimental study of the bio-oil production from sewage sludge by supercritical conversion process

Environment-friendly treatment of sewage sludge has become tremendously important. Conversion of sewage sludge into energy products by environment-friendly conversion process, with its energy recovery and environmental benefits, is being paid significant attention. Direct liquefaction of sewage sludge into bio-oils with supercritical water (SCW) was therefore put forward in this study, as de-water usually requiring intensive energy input is not necessary in this direct liquefaction. Supercritical water may act as a strong solvent and also a reactant, as well as catalyst promoting reaction process. Experiments were carried out in a self designed high-pressure reaction system with varying operating conditions. Through orthogonal experiments, it was found that temperature and residence time dominated on bio-oil yield compared with other operating parameters. Temperature from 350 to 500 °C and reaction residence time of 0, 30, 60 min were accordingly investigated in details, respectively. Under supercritical conversion, the maximum bio-oil yield could achieve 39.73%, which was performed at 375 °C and 0 min reaction residence time. Meanwhile, function of supercritical water was concluded. Fuel property analysis showed the potential of bio-oil application as crude fuel.     

Evaluation of Eremurus spectabilis for production of bio-oils with supercritical solvents

Eremurus spectabilis samples were liquefied in organic solvents (methanol, ethanol and acetone) with (sodium hydroxide and ferric chloride) and without catalyst in a cylindrical reactor at temperatures of 270, 290 and 310 °C under supercritical conditions. The effects of liquefaction parameters such as temperature, catalyst and solvent on product yields were investigated. The liquid products were extracted with diethyl ether and benzene using an extraction procedure. The product yields in supercritical methanol, ethanol and acetone were found to as 41.6%, 53.8% and 64.3% in the non-catalytic runs at 310 °C, respectively. The highest conversion was obtained in supercritical acetone in the presence of ferric chloride (10%) at same temperature in the catalytic runs. The produced liquids in acetone were analyzed and characterized by elemental, Fourier transform infrared spectroscopy (FT-IR), gas chromatography–mass spectrometry (GC–MS). The liquid products (bio-oils) obtained with acetone contained various types of components including aromatics, nitrogenated and oxygenated compounds. As the bio-oils obtained exhibit high heat values, E. spectabilis is presented as a potential feedstock candidate for production of bio-fuels or valuable chemicals.     

Improved method for the formation of recycled resins from depolymerized products of waste fiber-reinforced plastics: simple and effective purification of recovered monomers by washing with water

The synthesis of recycled plastics from recovered monomeric materials obtained from the depolymerization reaction of fiber-reinforced plastics (FRP) was examined. The depolymerization reaction of FRP in the presence of N,N-dimethylaminopyridine (DMAP) smoothly yielded the corresponding monomers, which mainly consisted of dimethyl phthalates. The polymerization reaction with this monomer failed to form the corresponding unsaturated polyesters due to contamination by N-methyl-4-pyridone, a decomposition product of DMAP. An efficient purification of the recovered monomer was achieved by washing with water, and the purified monomer successfully yielded the corresponding polymers. A hardness test revealed that the polymers were as hard as the polyester made from virgin materials. The present modification provides a practical method for the preparation of recycled plastics from depolymerized plastics.     

Decomposition and oxidation of sodium 3,5,6-trichloropyridin-2-ol in sub- and supercritical water

Sodium 3,5,6-trichloropyridin-2-ol (STCP) is a necessary precursor compound for the production of chlorpyrifos and triclopyr, which are extensively used as pesticide and herbicide, respectively. In the process of STCP production, however, large amount of wastewater containing STCP is discharged, which causes increasingly environmental concerns. Therefore, it is of great significance to develop a rapid and effective method for the disposal of containing STCP contaminants. In this work, the thermal decomposition of STCP in sub- and supercritical water was investigated using a continuous tubular reactor. While STCP was stable below 280 °C, it could be effectively decomposed at elevated temperature. FT-IR spectra of the decomposition products indicated that the pyridine ring structure in the STCP molecule was stable even at temperatures up to 400 °C. The decomposition reaction was mainly caused by the substitution of Cl groups in the STCP molecule with OH groups, resulting in polyhydroxylated pyridines as the major decomposition product. Moreover, high pressure favored the substitution reaction. To completely decompose STCP into non-toxic or low toxic compounds, supercritical water oxidation (SCWO) was employed to evaluate the oxidation of STCP using H₂O₂ as an oxidant. It was found that STCP could be completely oxidized to H₂O, CO₂ and corresponding inorganic ammonium salts with an oxidation rate of 99%.