基于本质安全的微反应器中苯乙烯聚合的数值模拟

重大化工事故往往是由多米诺效应引发的一连串故障而导致的。为实现苯乙烯聚合反应的本质安全,采用本质安全设计原则,设计了T型微反应器以替换传统釜式反应器。先通过计算流体力学(CFD)方法建立了三维稳态模型,再通过UDF(User Defined Functions)添加组分输运方程源项和能量方程源项,对苯乙烯自由基聚合反应进行了数值模拟,研究在微尺度条件下,反应温度、混合反应管道长度及形状对反应结果的影响。结果表明:由于微反应器可提高传热传质效率,在一定范围内反应温度可以控制在3 K以内;反应管道由0.15 m增长至1.5 m后,转化率可提高2倍左右;0.15 m直管形状改进为螺旋状后,转化率可至少提升4%。     

新型水滑石接枝污泥处理乳剂的合成与应用

以去除碳酸根后的镁铝水滑石正电胶团簇(LDHEPCL)作骨架,合成新型水滑石接枝污泥处理乳剂.用硫酸铈作引发剂,通过程序升温,实现了油包水多面液胞(W/O PHC)中丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)与去除碳酸根后的LDHEPcL接枝聚合,制得污泥处理乳剂--LDHEPCL-PAM-PDMDAAC共聚物乳剂.聚合升温速度为2.5℃/min,最高温度为(985±1)℃.各配料最佳摩尔比为LDHEPCL:AM:DMDAAC=0.15:0.57:0.28.与目前最好的污泥处理乳剂FLOPAMR EMZ35及STCPA EM6040相比,LDHEPCL-PAM-PDMDAAC共聚物乳剂具有絮团致密、絮层高度低、与聚合铝(PAC)及羧甲基壳聚糖(CMC)配伍较好等优点.     

化学破乳-Fenton氧化处理乳化液废水

采用化学破乳-Fenton试剂处理乳化液废水,考察了相关因素对处理效果的影响特点和规律.实验结果表明,酸化作用中,静电作用对破乳有着关键性影响,降低乳化液废水pH值,有利于乳化液废水的油水分离;混凝剂投加量和废水pH值直接决定着破乳效果,油滴分散体系脱稳的适宜pH值既能使油滴间静电斥力较小,又能使大分子量的、大比表面积的多核络合离子通过电中和、吸附架桥、卷扫的作用来强化油水分散体系脱稳.Fenton氧化中,对于特定的Fe2+浓度,随着n(H2O2)/n(Fe2+)增加,COD去除程度增加,但增加的幅度越来越小,同时COD去除率达到稳定所需要的时间相应增加,适宜的摩尔比为20;废水Fenton体系H2O2开始阶段急速降低然后趋于平缓,体系Fe2+反应开始很短时间内急剧降低并趋于某一稳定值,H2O2浓度、Fe2+浓度随时间变化遵循一级反应动力学模型.     

Influence of surfactant concentration on foliar retention of pesticides used in forestry

Abstract

Aqueous tank mixes of permethrin, fenitrothion, Bacillus thuringiensis (B.t.), diflubenzuron (DFB), and glyphosate containing different amounts of Triton® X‐114, a nonionic surfactant, were prepared. Glyphosate formed clear solutions, permethrin and fenitrothion formed emulsions, DFB and B.t provided suspensions. Emulsion stability of permethrin and fenitrothion increased with increasing surfactant level, while the emulsion drop size decreased.

Foliage of white oak, trembling aspen, white spruce and balsam fir were dipped in tank mixes of pesticides (except B.t.) labelled with ¹⁴carbon. The amount of pesticide retained on foliage was determined by liquid scintillation counting. Foliage was also dipped in non‐radioactive B.t. tank mixes, and the protein retained was determined colorimetrically. With all tank mixes, a direct relationship was observed between the mass of liquids retained on foliage and liquid viscosity. In contrast, the amount of pesticide retained was unaffected by viscosity, but was influenced by emulsion drop size. Initially, the amount of pesticide retained on foliage increased with increasing surfactant concentration. Beyond an optimum surfactant level, the emulsion drop sizes were too small and the emulsions became too stable to allow maximum retention of pesticides on foliage. With the glyphosate solutions, however, no optimum surfactant level was indicated because foliar concentrations continued to increase with increasing surfactant levels.     

乳化液膜法提取苯酚的动力学研究

研究了以双丁二烯亚胺－煤油作膜相,ＮａＯＨ溶液为内水相的乳化液膜提取苯的动力学特性,测定了膜相与内外水相组成,搅拌速度,温度对提取速率的影响,得出了提取速率规律。     

混凝剂循环使用及化学混凝处理乳化废液的研究

对乳化废液进行了不完全的化学混凝处理 ,优化出的混凝剂为PAC +PAM ,最佳条件为 :PAC ,1 0～ 2 0g/L ;PAM ,2 0mg/L ;pH ,6 5～ 8 5 ;混凝后的出水COD在 5 0 0～ 5 6 0 0mg/L之间 ,可以用来重新配制乳化液 ,性能指标达到国家规定要求 ;混凝产生的絮渣采用浓硫酸处理 ,每升乳化废液混凝产生的絮渣用 4 5mL浓硫酸 ,处理后回收油品 15mL/L ,混合液可循环使用处理乳化废液 ;将出水回用于配制新乳化液 ,实现了废水循环利用、清洁生产的目的     

用废聚对苯二甲酸乙二醇酯制备对苯型不饱和聚酯树脂

用废聚对苯二甲酸乙二醇酯(PET)制备对苯型不饱和聚酯树脂。考察了醇解时间对醇解产物、聚合温度对反应产物的影响。该方法的主要工艺参数为：废PET：PG(摩尔比)等于1：1．5,废PET：MA(摩尔比)等于1：1,醇解温度190～200℃,醇解时间3．5～4h,聚合温度190～210℃,聚合反应时间1．5～2h。试验所得对苯型不饱和聚酯树脂产品的性能符合企业通用型不饱和聚酯树脂的标准。     

Degradation of Cellulosic Materials Under the Alkaline Conditions of a Cementitious Repository for Low- and Intermediate-Level Radioactive Waste. II. Degradation Kinetics

The degradation of cellulosic materials, differing mainly in the degree of polymerization and the number of reducing end groups, was studied under the alkaline conditions similar to those existing in a cementitious repository for low- and intermediate-level radioactive waste (pH 13.3, T = 25°C). The kinetics of alkaline degradation (peeling-off reaction) were studied and the data analyzed by the model of Haas et al. [13]. The observed kinetic parameters for the propagation reaction and overall stopping reaction were compared with literature data. Although measured under different experimental conditions, literature data and data from this study show a consistent picture. Differences in the extent of degradation observed for the different cellulosic materials could be satisfactorily explained by differences in reducing end group content and, consequently, by differences in the degrees of polymerization. Besides the number of reducing end groups, the degree of amorphousness also plays an important role. The main degradation products formed under the experimental conditions used are - and -(gluco)isosaccharinic acid. This is in agreement with many other studies on alkaline degradation of cellulose. The two isomers are formed in roughly equal amounts.     

焦化废水脱酚的工艺研究

为脱除焦化废水中的酚，本文研究了新型化学破乳法液膜脱酚的工艺，确定了搅拌塔操作条件，并实际应用于焦化厂含酚废水的处理中，结果表明该工艺具有良好的脱酚效果。     

破乳-混凝-光催化氧化法处理废切削液

采用破乳—混凝—光催化氧化法处理废切削液。先用HNO3破乳;然后用聚硫酸铁(PFS)和阳离子聚丙烯酰胺(PAM)复合混凝废切削液,在废切削液pH=7.5、PFS加入量为1500mg/L、PAM加入量为8mg/L的条件下,混凝效果较好;在混凝后上层清液pH=3、H2O2加入量为60mg/L、FeSO4.7H2O加入量为700mg/L、H2O2分4次加入、紫外光照射6.5h的条件下,COD去除率达98.91%。