用生物滴滤塔净化苯乙烯废气

用内部填充有陶粒的生物滴滤塔净化苯乙烯废气,考察了气体流量、液体喷淋量及氮源对苯乙烯废气净化效果的影响。,进口苯乙烯质量浓度为300～4500mg／m^3时,气体流量和进FI苯乙烯质量浓度对苯乙烯的去除率影响显著,当气体流量为0．3m^3／h时,苯乙烯去除率达87％以上。实验结果表明：在气体流量为0．9m^3／h时,液体喷淋量对苯乙烯废气的净化效果影响不明显;降低进口苯乙烯质量浓度和增大生物滴滤塔的有效传质面积,有利于苯乙烯的净化;用浓度为0.0017mol／L的NaNO3作氮源时苯乙烯的去除效果优于用NH4Cl作氮源时苯乙烯的去除效果。     

介质阻挡放电低温等离子体协同催化降解苯乙烯

采用介质阻挡放电(DBD)低温等离子体协同催化降解苯乙烯,考察了输入功率、初始苯乙烯质量浓度、气体湿度、停留时间、脉冲频率等因素对苯乙烯降解率和能量效率的影响,建立了苯乙烯降解动力学模型,探讨了苯乙烯的降解机理。结果表明：在输入功率30 W、初始苯乙烯质量浓度464 mg/m³、气体相对湿度30%、停留时间0.18 s、脉冲频率200 Hz的最佳工艺条件下,苯乙烯降解率为62.20%,能量效率为36.10 g/(kW·h);DBD等离子体降解苯乙烯的动力学过程符合准一级动力学模型,相应的反应速率常数为0.109 4 m3^/(W·h)。DBD等离子体降解苯乙烯主要通过活性物种e^-、·O、·OH和NO₂·等对苯乙烯进行氧化。与单独DBD等离子体工艺相比,在相同输入功率下,DBD协同催化工艺能有效提高苯乙烯降解率和矿化率,降低反应器出口O₃浓度。     

金属有机骨架材料对苯乙烯废气的吸附

采用溶剂热法合成了金属有机骨架(MOF)材料MIL-101、UiO-66和HKUST-1，运用多种技术手段进行了表征，考察了3种MOF材料对苯乙烯的吸附性能。表征结果显示：3种MOF材料均具有较好的分散性、晶体颗粒均匀；MIL-101、HKUST-1和UiO-66的比表面积分别为2 510,1 147,742 m²/g。实验结果表明：在MOF材料用量3.0 g、温度25℃、压力101 kPa的条件下，MIL-101、UiO-66和HKUST-1对苯乙烯的平衡吸附量分别为795,197,126 mg/g;MIL-101对苯乙烯的吸附过程符合准二级动力学模型；MIL-101吸附苯乙烯的过程分为表面吸附、颗粒内扩散和微孔吸附3个阶段，3个阶段对苯乙烯吸附量的贡献率分别为32.5%、61.8%和5.7%;3次连续吸附-脱附实验后，MIL-101对苯乙烯的吸附量基本保持不变，脱附率为98%，远高于木质活性炭(68%)，表现出良好的吸附性能和可再生性。     

高吸油树脂处理苯乙烯废水

以4-叔丁基苯乙烯为单体,采用自由基悬浮聚合法合成了颗粒状高吸油树脂。探讨了高吸油树脂对苯乙烯废水的静态吸收性能和动态吸收性能。实验结果表明：苯乙烯去除率随苯乙烯初始质量浓度的增加和处理时间的延长而提高,最佳处理时间为6h;随吸收柱进水流量增大,苯乙烯去除率先提高后降低,进水流量为15mL／min、处理时间为6h时,苯乙烯去除率最大,为96．25％;苯乙烯去除率与处理时间的关系很好地遵循了Hill方程。高吸油树脂对苯乙烯的吸收过程遵循一级动力学规律,相关系数为0．998。     

苯乙烯、甲苯等有机蒸汽在DG-3催化剂上的催化燃烧

本文研究了甲苯、苯乙烯在金属氧化物上催化燃烧的活性规律;对甲苯在四种金属氧化物上的反应动力学进行了考察,测定了动力学参数;并以碱金属氧化物为活性组份,硅-铝蜂窝状炉瓦片为载体,由浸渍法制得DG-3催化剂。此催化剂用于苯乙烯、甲苯等有机蒸汽的催化燃烧时,具有与贵重金属催化剂相近的起燃温度。在空速sv>1×10~4时~(-1),苯乙烯和甲苯浓度分别为5×10~3毫克/米~3和2×10~3毫克/米~3左右时,床层温度在280℃和300℃左右即可使净化率达到99％以上。     

利用废弃泡沫塑料制苯乙烯技术研究成功

随着发泡聚苯乙烯塑料制品在工农业，尤其在食品、轻工、机械包装工业等方面的大量应用，其废弃物由于不能生物降解而成为影响环境的“白色污染”，这是近年来公众最为关注的环境问题之一。目前，世界各国都在积极寻找回收、利用这些废弃泡沫塑料的有效途径。武汉现代工业技术研究院近几年来致力于该项目的研究，研究成功治理“白色污染”的行之有效的方法，即利用废弃泡沫塑料制苯乙烯。苯乙烯是一种单体原料，可以用于制ＡＢＳ塑料、聚苯乙烯、聚酯树脂、丙烯酸树脂等，在化工行业有着广泛的用途。近年来，苯乙烯的价格不断上涨，且供不应…     

混凝法处理丙烯腈-丁二烯-苯乙烯树脂废水

以聚合氯化铝铁为混凝剂、阴离子型聚丙烯酰胺为助凝剂,采用混凝法处理丙烯腈-丁二烯-苯乙烯树脂（ABS）废水（简称废水）,考察了聚合氯化铝铁加入量、沉降时间、搅拌转速、搅拌时间、废水pH和混凝温度对废水处理效果的影响。实验结果表明,在聚合氯化铝铁加入量50mg／L、阴离子型聚丙烯酰胺加入量2mg／L、废水pH6．0～8．0、快速搅拌1min、慢速搅拌6min、沉降时间25min、混凝温度20～25℃的条件下,废水的SS去除率达97％以上,COD去除率达77％以上。     

WSH-2型催化剂在环氧丙烷/苯乙烯装置废气处理中的工业应用

介绍了WSH-2型催化剂在环氧丙烷（PO）/苯乙烯（SM）装置废气处理中的应用。工业化装置的运行结果表明,在废气处理量86 000 Nm³/h、设定反应器进口温度250~300 ℃、设定进口非甲烷总烃（NMHC）质量浓度1 000~2 200 mg/m³的条件下,无论单系列还是双系列运转,采用WSH-2型催化剂均可对废气进行有效处理。处理后气体中的NMHC、苯、甲苯、乙醛、SM等的含量均符合GB 16297—1996《大气污染物综合排放标准》和GB 14554—1993《恶臭污染物排放标准》中的相关规定。NMHC去除率达到92.9%以上,装置运行稳定。按照目前的废气排放工况推算,预计催化剂的使用寿命可达5 a。     

1,4-丁二醇精馏残液制备四氢呋喃

针对目前国内Reppe法生产1,4-丁二醇(BDO)精制过程中产生大量难处理的精馏残液的现状,采用减压精馏,在真空度-75 k Pa的条件下处理BDO精馏残液,脱除其中的低级醇、水和高级醇等,得到粗BDO。再采用磺酸树脂催化剂,在103~105℃条件下将质量分数为80%~85%的粗BDO催化环化,得到粗四氢呋喃(THF),粗THF经精馏、固体氢氧化钠脱水、4A分子筛脱水后得到纯度为99.95%、水含量小于70 mg/kg的THF成品。     

氧化苯乙烯生产中副产物的回收利用

汉中市日用化工厂氧化苯乙烯生产车间的三个主要工序,在生产过程中均有部分副产物产生。对于这些副产物,将其外排势必会污染环境,但至今又未找到合适的处理方法,只是给附近的农户作为燃油用,这样,仍会造成一定的环境污染。我们对这些副产物进行了回收利用的初步探索,并获得了一定的效果。试验结果表     

Enhanced styrene recovery from waste polystyrene pyrolysis using response surface methodology coupled with Box–Behnken design

A work applied response surface methodology coupled with Box–Behnken design (RSM-BBD) has been developed to enhance styrene recovery from waste polystyrene (WPS) through pyrolysis. The relationship between styrene yield and three selected operating parameters (i.e., temperature, heating rate, and carrier gas flow rate) was investigated. A second order polynomial equation was successfully built to describe the process and predict styrene yield under the study conditions. The factors identified as statistically significant to styrene production were: temperature, with a quadratic effect; heating rate, with a linear effect; carrier gas flow rate, with a quadratic effect; interaction between temperature and carrier gas flow rate; and interaction between heating rate and carrier gas flow rate. The optimum conditions for the current system were determined to be at a temperature range of 470–505 °C, a heating rate of 40 °C/min, and a carrier gas flow rate range of 115–140 mL/min. Under such conditions, 64.52% WPS was recovered as styrene, which was 12% more than the highest reported yield for reactors of similar size. It is concluded that RSM-BBD is an effective approach for yield optimization of styrene recovery from WPS pyrolysis.     

苯乙烯废水活性炭吸附装置的评价及改进研究

对抚顺石化公司化工塑料厂苯乙烯废水活性炭吸附装置的预处理设施、活性炭吸附及再生性能进行了评价，分析了出水水质超标的主要原因，用混凝沉淀－砂滤流程改进了原处理工艺，使出水水质得到了显著改善。     

Reduction of tar using cheap catalysts during sewage sludge gasification

Solid-fuel conversion or gasification study of sewage sludge and energy recovery has become increasingly important because energy recovery and climate change are emerging issues. Various types of catalysts, such as dolomite, steel slag and calcium oxide, were tested for tar reduction during the sewage sludge gasification process. For the experiments on sewage sludge gasification reactions and tar reduction using the catalysts, a fixed bed of laboratory-scale experimental apparatus was set up. The reactor was made of quartz glass using an electric muffle furnace. The sewage sludge samples used had moisture contents less than 6%. The experimental conditions were as follows: sample weight was 20 g and reaction time was 10 min, gasification reaction temperature was from 600 to 800°C, and the equivalence ratio was 0.2. The quantity of catalysts was 2–6 g, and temperatures of catalyst layers were 500–700°C. As the reaction temperature increased up to 800°C, the yields of gaseous products and liquid products increased, whereas char and tar products decreased, showing effects on gas product compositions. These results were considered to be due to the increase of the water-gas reaction and Boudouard reaction. In the case of experiments with catalysts, dolomite (4 g), steel slag (6 g) and calcium oxide (6 g) were used. When the temperature of catalysts increased, the weight of the tar produced decreased with different cracking performances by different catalysts. Reforming reactions were considered to occur on the surface of dolomite, steel slag and calcium oxide, causing cracking of the hydrocarbon structure, which eventually showed reduced tar generation.     

废聚苯乙烯泡沫塑料的催化裂解

为了对废聚苯乙烯泡沫塑料（WPS）资源化利用,通过对WPS进行催化裂解的方法,研究了催化剂种类和裂解温度对裂解时间、裂解油产率、苯乙烯回收率以及裂解油纯度的影响。研究结果表明,催化剂种类和裂解温度对裂解反应有着重要影响。裂解温度升高,裂解油产率提高,裂解时间缩短,但苯乙烯选择性下降;低于380 ℃时,氧化钙的裂解油产率和裂解时间优于氧化铝和氯化铝,但苯乙烯的选择性劣于氧化铝和氯化铝;高于400 ℃时,氯化铝、氧化铝和氧化钙的催化活性接近。在实验条件下,WPS催化裂解的最佳催化剂为氯化铝,380 ℃下的裂解时间为25 min,裂解油产率为85.48%,裂解油中苯乙烯含量为80.66%（w）,且副产物较少。     

Styrene/Lignin-Based Polymeric Composites Obtained Through a Sequential Mass-Suspension Polymerization Process

A modified sequential mass-suspension polymerization was employed to ensure adequate dispersion of lignin into the monomeric phase. Due to its complex macromolecular structure and low compatibility with styrene, eucalyptus wood-extracted lignin, via a modified Kraft method, was esterified with methacrylic anhydride to ensure organic phase homogeneity into the reaction medium. Infrared spectroscopy showed a decrease in the hydroxyl band, a characteristic of natural lignin (3200–3400 cm^?1) and an increase in the characteristic ester band (1720–1740 cm^?1) whereas nuclear magnetic resonance measurements exhibited intense peaks in the range from 1.7 to 2.05 ppm (–CH₃) and 5.4 to 6.2 ppm (=CH₂), related to methacrylic anhydride. Comparatively, the esterified lignin also displayed an increase of its glass transition temperature for 98?°C, related to natural lignin, whose T _g was determined to be equal to 91?°C. Styrene/lignin-based polymers exhibited higher average molar masses in comparison to the values observed for polystyrene synthesized with similar amounts of benzoyl peroxide, due to the ability of lignin to act as a free-radical scavenger. Composites obtained with styrene and natural or esterified lignin were successfully synthesized, presenting regular morphology and proper lignin dispersion. Based on a very simple polymerization system, it is possible to enhance the final properties of polystyrene through the incorporation of lignin, which represents an important platform for developing attractive polymeric materials from renewable resources.     

Crystallization and Mechanical Properties of Recycled Poly(ethylene terephthalate) Toughened by Styrene–Ethylene/Butylenes–Styrene Elastomer

Recycled poly(ethylene terephthalate) (R-PET) was blended with 15–30 wt% of styrene–ethylene/butylenes–styrene (SEBS) block copolymer and maleic anhydride grafted SEBS (SEBS-g-MA). Effects of nucleation and toughening of the elastomers were evaluated systematically by study of morphology, crystallization, thermal and mechanical properties of the blend. The addition of 30 wt% SEBS promoted the formation of co-continuous structure of the blend and caused the fracture mechanism to change from strain softening to strain hardening. Addition of SEBS-g-MA resulted in significant modification of phase morphology and obviously improved the impact strength. The compatibilization reaction of PET with SEBS-g-MA accelerated the crystallization of PET and increased the crystallinity. The shifts in glass transition temperature of PET towards that of SEBS-g-MA and the higher modulus for R-PET/SEBS-g-MA (70/30) blend found by DMA are also indications of better interactions under the conditions of compatibilization and interpenetrating structure.     

Gasification characteristics of biomass for tar removal by secondary oxidant injection

Gasification experiments for sawdust were conducted using a fixed bed reactor at 900 °C by varying the secondary oxidant injection ratio to determine the optimal conditions for tar removal along with the enhancement of gasification efficiency. Secondary oxidant was injected as an oxidant at the top zone of the gasifier in varying ratios of 10–30% of the total amount of oxidant. This method was based on the primary method of tar removal and gasification efficiency improvement by thermal cracking of tar. Various gasification performance parameters were evaluated and tar content was estimated by measuring the fluctuation of weight of the activated carbon filter. The results showed that the concentration of tar in the producer gas decreased by injecting the secondary oxidant, even though syngas yield decreased. The recycling potential of the char produced in the gasification experiments was also assessed with the purpose of utilizing char as an adsorbent by determining its surface area and pore volume. The results demonstrated that the char produced from the gasification experiment had similar quality to that of the activated carbon used in this experiment.     

Application of dissolved air flotation on separation of waste plastics ABS and PS

The aim of this research was to separate waste plastics acrylonitrile butadiene styrene (ABS) and polystyrene (PS) by dissolved air flotation in a self-designed dissolved air flotation apparatus. The effects of wetting agents, frother, conditioning time and flotation time on flotation behavior of waste plastics ABS (w-ABS) and PS (w-PS) were investigated and the optimized separation conditions were obtained. The results showed that when using 25 mgL(-1) tannic acid, 5 mgL(-1) terpineol, 15 min conditioning time and 15 min flotation time, mixtures of w-ABS and w-PS were separated successfully by dissolved air flotation in two stages, the results revealed that the purity and recovery rate of w-PS in the floated products were 90.12% and 97.45%, respectively, and the purity and recovery rate of w-ABS in the depressed products were 97.24% and 89.38%, respectively. Based on the studies of wetting mechanism of plastic flotation, it is found that the electrostatic force and hydrophobic attraction cannot be the main factor of the interaction between wetting agent molecules and plastic particles, which can be completed through water molecules as a mesophase, and a hydrogen bonding adsorption model with hydration shell as a mesophase was proposed.     

生物质热解焦油脱除方法研究进展

生物质热解焦油的产生不仅降低了热解效率,影响设备运行,更危害着人类健康。通过介绍生物质热解焦油的特性及危害、对比分析目前各种不同除焦方法(文丘里法、旋风分离法、电捕焦法、高温裂解法和催化裂解法)的特点及应用前景,得出采用多种方法组合的形式进行联合除焦可显著提高焦油脱除效率。寻找用于湿法除焦的可再生利用的有机溶剂,开发经济、高效、长寿命的催化剂将成为生物质热解焦油脱除技术开发的重点。     

Tar Balls: The End State

Tar balls are frequently reported as an indicator of the extent of the impact of a spill incident. The determination of the density of tar balls is basic to the shoreline cleanup assessment team (SCAT) process, and is frequently used by the media as an indication of oil pollution. The processes involved in the evolution of tar balls are not well understood and there is a paucity of literature on the science of tar ball formation.