典型焦化厂大气挥发性有机物排放表征分析

焦化行业是我国重要工业类别,但因其工艺过程复杂,所以VOCs（挥发性有机物）排放特征尚不明确.以典型机械焦化厂为研究对象,对焦炉烟囱、推焦、装煤和焦炉顶等不同排放环节进行采样,并利用GC/MS（气相色谱质谱联用仪）进行多物种分析,并对焦化厂排放VOCs的OFP（生成O₃的潜势）进行探索性研究.结果表明:①焦化厂排放的VOCs包括烷烃、烯烃、炔烃、芳香烃、卤代烃和含氧VOCs等六大类,共90多个物种.②不同环节排放的ρ（VOCs）差异显著,其中,焦炉烟囱ρ（VOCs）排放量（87.1 mg/m3）最大,其次为推焦（4.0 mg/m3）、装煤（3.3 mg/m3）和焦炉顶（1.1 mg/m3）.③不同环节排放的VOCs种类不同,但均以烷烃和烯烃为主,其中,焦炉烟囱排放的烯烃最多（占比达66%）,装煤和推焦排放的则以烷烃为主（占比分别为42%和36%）,焦炉顶排放的烷烃和烯烃相近（占比分别为31%和29%）.④基于排放特征和最大增量反应活性法研究发现,焦炉烟囱是焦化厂VOCs减排的重点环节,烯烃是重点减排的物种,特别是乙烯、丙烯、丁烯和1,3-丁二烯等,但乙醛、苯、甲苯等也不容忽视.研究显示,以乙烷/丙烷/乙烯（三者质量浓度之比）为指标,可明显区分焦炉烟囱、推焦、装煤和焦炉顶等不同环节的VOCs排放.      

吸附反应时间对除草剂阿特拉津吸附行为的影响

采用批量动态实验方法,对潮土中阿特拉津吸附特征随吸附反应时间变化进行了研究。结果表明,土壤吸附的阿特拉津量随反应时间的变化符合双曲线函数关系。在50μg·L-1～2000μg·L-1浓度系列下,在48h内,土壤颗粒对阿特拉津的吸附属于快反应,土壤吸附的阿特拉津量随吸附反应时间呈指数上升,为吸附实验结束(168h)时土壤吸附阿特拉津总量的58%到90%。当吸附反应时间超过48h后,随反应时间增加,土壤吸附阿特拉津量差异变化不显著。阿特拉津在潮土颗粒和土壤溶液中的相分配可用Freundlich方程描述。吸附容量因子Kf与吸附反应时间之间有极显著的线性正关系(r2=0.9063**,p<0.0001)。无量纲的非线性因子n与吸附反应时间之间也具有显著的线性负关系(r2=0.5666*,p=0.0192)。     

基于腐蚀与盐堵塞问题的超临界水氧化研究进展

超临界水氧化(简称SCWO)以其特有的优点成为了引人注目的有机废水处理方法.在操作过程中,有机物与氧化剂呈现为快速的均相反应,在数分钟内便可完全氧化生成CO2和H20.尽管已建造了工业规模的SCWO装置并用于处理化学废水,但该技术所存在的设备腐蚀以及设备因盐沉积而堵塞的问题制约着该技术的推广应用.为解决上述问题,科技工作者对SCWO工艺进行了改进,并提出了多种新颖的SCWO反应器设计思想.综述了基于解决设备腐蚀与盐堵塞问题的SCWO研究进展,并对相关问题进行了讨论.     

Sonolytic reactions of phenanthrene in organic extraction solutions

Ultrasonic extraction is a common method used to extract semi-volatile and nonvolatile organic compounds such as polycyclic aromatic hydrocarbons (PAHs) from solid matrices. However, ultrasonic energy has been suspected to lead to undesired reactions of the solute and thus affect qualitative and quantitative results. In this paper, sonolytic reactions of phenanthrene in common organic extraction solutions were examined using a 20 kHz ultrasonic probe under conditions commonly used for ultrasonic extraction. Extraction parameters including phenanthrene concentration, solvent type, pulse length, and sonication time were investigated. Hexane:acetone (1:1 V/V) resulted in less phenanthrene degradation than dichloromethane (DCM):acetone (1:1 V/V). Initial solute concentration, length of sonication time, and solvent type affected the degradation of phenanthrene. Reaction byproducts including methylphenanthrene and methylnaphthalene detected after sonication indicate that phenanthrene reacts by both direct pyrolysis and reaction with methyl or ethyl radicals formed from solvent pyrolysis.     

环境水体中肠道病原细菌定量PCR检测与膜过滤分析方法的比较

采用通用引物,通过实时荧光定量PCR方法(QPCR),对西安市5个地表水体中肠道病原细菌的细胞密度进行了分析.检测水样体积为100mL,分别于2006年3～6月取自水源水(黑河)、景观娱乐用水(大唐芙蓉园北湖和兴庆湖)、纳污河(浐河)和未消毒的二级出水(北石桥污水处理厂),并将QPCR检测结果与滤膜法(MF)测得的细菌总数、大肠菌群和粪大肠杆菌CFU结果进行了比较分析.5个水体(n=60)检测结果显示,QPCR检测结果是大肠菌群CFU的2.2～5倍,是粪大肠杆菌CFU的7～14倍.病原细菌检测的几何平均值范围,QPCR法在25～67000 CCE·100mL-1之间,MF法大肠菌群在3～45000 CFU·100mL-1之间,粪大肠菌群在0～3000 CFU·100mL-1之间(n=60).两种方法的检测结果使用Spearman秩相关法来计算,结果显示,QPCR检测结果与大肠菌群、细菌总数以及粪大肠杆菌CFU均呈现显著正相关,秩相关系数分别为r=0.983、r=0.908和r=0.948.     

临安近地面臭氧变化特征分析

利用2003年11月─2004年11月浙江临安区域大气本底站近地面臭氧浓度的连续监测资料,研究了地面臭氧浓度全年总体分布、季节变化、日变化及浓度频率分布规律.结果表明,该地区φ(O₃)全年平均值为32.41×10-9,其日变化呈明显单峰型, 14:00左右达到最大值, 约04:00出现最小值.φ(O₃)月均值在春末夏初达到最大值,在12月─次年2月出现最小值.φ(O₃)各月的平均振幅在夏季达到最大,说明临安本底站夏季臭氧光化学反应比较强烈.除冬季外,其他季节该地区近地面φ(O₃)均有超过《环境空气质量标准》(GB30952-1996)二级标准的情况,全年超标率为0.96%.      

Self-ignition in stone wool insulation contaminated with fatty acid (fundamentals,case study,analysis methodology)

A combination of a residual film of flammable organic substance, air and porous structures like insulation material (e.g. stone wool) may result in a fire. The initiating self-heating process depends on the substance (reactivity, volatility), amount of accumulated liquid, volume and temperature. Specific information is given for application and extension of the Thomas criterion with a 2nd order reaction. The experimental part includes new experimental techniques to determine heat transfer and formal reaction kinetic data. The applied self-ignition temperature (SIT) simulation model relies on liquid film volume and not on liquid film surface reaction. As a further result of the studies detailed working procedure of three simplified methodologies for estimation of SITs in technical scale are presented. New techniques to determine parameters necessary for SIT prediction, especially in combination with Methodology III, have the power to reduce the costs for estimating the SIT up to 80%.     

Heterogeneous reaction of SO2 on CaCO3 particles: Different impacts of NO2 and acetic acid on the sulfite and sulfate formation

Despite the heterogeneous reaction of sulfur dioxide (SO₂) on mineral dust particles significantly affects the atmospheric environment, the effect of acidic gases on the formation of sulfite and sulfate from this reaction is not particularly clear. In this work, using the in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique, we employed a mineral dust particle model (CaCO₃) combined with NO₂ and acetic acid to investigate their effects on the heterogeneous reaction of SO₂ on CaCO₃ particles. It was found that water vapor can promote the formation of sulfite and simulated radiation can facilitate the oxidation of sulfite to sulfate. The addition of NO₂ or acetic acid to the reaction system altered the production of sulfate and sulfite accordingly. There was a synergistic effect between NO₂ and SO₂ that promoted the oxidation of sulfite to sulfate, and a competitive effect between acetic acid and SO₂ that inhibited the formation of sulfite. Moreover, light and water vapor can also affect the heterogeneous reaction of SO₂ with the coexistence of multiple gases. These findings improve our understanding of the effects of organic and inorganic gases and environmental factors on the formation of sulfite and sulfate in heterogeneous reactions.     

CL-20/HTPB热分解机理的ReaxFF/lg反应分子动力学模拟

目的 揭示CL-20和HTPB复合体系的热分解机理,同时为CL-20/HTPB复合推进剂配方设计与应用提供理论依据。方法 采用反应分子动力学方法(ReaxFF/lg),研究CL-20/HTPB混合体系在2 500~3 500 K中5个温度下的热分解机理。结果 混合体系中的CL-20分子间反应路径仍为脱硝基和开环等反应。HTPB为混合体系引入大量的H原子与OH基团,这些自由基会与CL-20及CL-20的分解产物发生反应,例如与HNO2的大量化学反应促进了CL-20的热分解。相比CL-20单质体系,混合体系下,HNO2生成反应数量均有不同程度的增加。通过与单组分产物数量的比较可以发现,H2O的含量大大增加,且曲线到达峰值的时间更短,体系分解反应速率更快,同时CO2的含量也大幅度地减少。除此之外,所计算的混合体系的活化能(Ea)与指前因子的自然对数lnA分别为114.684 kJ/mol与25.896。对比CL-20单质体系,混合体系的活化能较小。结论 HTPB会对CL-20的热分解起到促进的作用,降低了系统对热刺激的不敏感程度。     

Reuse of spent bleaching earth by polymerisation of residual organics

Spent bleaching earth (SBE) is a waste generated by the edible oil industry that currently has limited options for beneficial reuse. In excess of ～2 million tonnes per year of SBE is generated world-wide with major quantities available in the middle-east where significant volumes of edible oils are produced. Low pressure compaction followed by heat treatment at 150 °C causes polymerisation of the residual organic components in SBE and this produces monolithic samples with high unconfined compressive strengths (54 MPa). SBE can therefore be used to manufacture novel clay blocks for use in construction that are bonded by polymerised vegetable oil. This represents a new, innovative and resource efficient application for SBE. In this research, commercial SBE has been characterised and the effects of key processing variables (temperature and compaction pressure) on the compressive strength, porosity and density of the SBE clay blocks are reported and the mechanisms responsible for strength development are discussed.