废旧聚苯乙烯塑料裂解制备苯乙烯的方法研究

对聚苯乙烯塑料(PS)催化裂解制备苯乙烯的方法进行研究, 对聚苯乙烯热裂解的机理进行了分析, 考察了不同催化条件对聚苯乙烯裂解产物的影响.     

高抗冲聚苯乙烯热裂解的研究

高抗冲聚苯乙烯大量使用,废弃物容易造成白色污染。采用热裂解的方式回收单体具有良好的社会价值和经济效益。研究了HI825、HI1662D、HI1662G、HI2757和2717等5种高抗冲聚苯乙烯的热裂解,对上述几种聚苯乙烯热裂解产物进行了色谱分析,并与废聚苯乙烯回收料热裂解产物作了比较。在热裂解温度375～450℃下,考察了温度对各种型号聚苯乙烯热裂解液体产率以及液相产物组成的影响,得出在450℃下液体产率较高,但苯乙烯选择性在425℃邻近较高。废聚苯乙烯热裂解液相产物主要为苯乙烯(占70%～80%)。高冲聚苯乙烯热裂解液相产物中苯乙烯较少(占40%～70%),相应甲苯和乙苯含量较高,分别占10%～20%和10%～25%。     

废聚苯乙烯裂解制备低聚苯乙烯及苯乙烯单体

以废聚苯乙烯为原料，利用裂解法制备低聚苯乙烯及苯乙烯。实验表明，较低裂解温度，一次加料方式有利于低聚苯乙烯的制备；较高裂解温度，连续加料方式有利于苯乙烯的制备；控制反应时间可以控制低聚苯乙烯的分子量。     

热重-红外-气相色谱/质谱联用研究聚苯乙烯的裂解特征

采用热重-红外-气相色谱/质谱(TGA-FTIR-GC/MS)联用技术,研究了重均分子量为2.400×103~1.724×105g/mol的不同分布范围内的3种聚苯乙烯的热裂解特征。以氮气为载气,在50~500℃范围内,比较了3种聚苯乙烯的失重曲线、裂解产物的红外光谱和总离子流色谱。结果表明,不同分子量的聚苯乙烯之间的热裂解、红外光谱、气相色谱/质谱检测结果均存在一定的差异性,相同分布宽度、不同分子量的聚苯乙烯之间的TGA、FTIR、GC/MS检测结果相近。该方法为不同分子量及分布的聚苯乙烯性能的深入研究及聚苯乙烯用于仪器性能验证、比较等提供了基础数据。     

高抗冲击聚苯乙烯的热裂解气相色谱／质谱分析

利用热裂解气相色谱/质谱法对高抗冲击聚苯乙烯(HIPS)树脂样品进行了分析。通过总离子图分析，给出了其热裂解产物，并结合化学萃取分离方法确定了HIPS的组成为聚苯乙烯和聚丁二烯的共混物，其质量分数分别为0．943和0．057。     

从废旧聚苯乙烯泡沫塑料中回收苯乙烯

本文采用有机溶剂甲苯作为消泡剂，用热裂解法从废旧聚苯乙烯泡沫塑料中回收苯乙烯，苯乙烯收率可达８０％以上。     

废聚苯乙烯催化热裂解制苯乙烯的研究

研究了碱土金属氧化物和过渡金属氧化物对废聚苯乙烯（PS）热裂解的催化效果;考察了催化剂碱性对裂解结果的影响。开发了一种以CaO为主体、MgO和NaOH为助剂的混合催化剂。结果表明：混合催化剂对废PS裂解具有良好的催化性能。实验同时考察了废PS催化裂解温度对混合催化剂活性以及催化裂解产物组成的影响。     

从废旧聚苯乙烯泡沫塑料中回收苯乙烯

本文采用有机溶剂甲苯作为消泡剂，用热裂解法从废旧聚苯乙烯泡沫塑料中回收苯乙烯，苯乙烯收率可达８０％以上。     

废弃聚苯乙烯泡沫塑料的回收及再利用

从聚苯乙烯泡沫塑料(EPS)的破碎填充、再生方法及利用、裂解和焚烧4个方面综述了近年来EPS的回收利用情况。     

城市废塑料裂解制汽油的研究(译文)

本文叙述了废塑料无催化剂作用下的高温裂解。在这项研究中，使用了三种类型的废塑料：聚苯乙烯（PS）、聚乙烯（PE）、聚丙烯（PP）。废塑料可以裂解为三种馏分：气体、液体以及固态残渣。液体产品通常由一些具有较高沸点的碳氢化合物组成。为了从裂解油中获得有用的汽油组分，可以对裂解油进行分馏。许多化工原材料包括苯、甲苯和其它芳香族碳氢化合物也可通过提纯裂解油来获得。结果表明，废PS可产生较多的液体，主要是苯乙烯，而废PE和PP则会产生较多的气体产品。     

Co-pyrolytic behaviors of biomass and polystyrene: Kinetics,thermodynamics and evolved gas analysis

The pyrolytic degradation mechanism of chestnut shell (CNS) and its blend with waste polystyrene (PS) were investigated. Individual pyrolysis behavior of samples obtained separately was compared with those of the blends using a combined TGA/MS/FT-IR system. To elaborate kinetic analysis and to determine kinetic parameters, distributed activation energy model (DAEM) was used. The average activation energy of co-pyrolytic decomposition reaction was 191.6 kJ/mol, while the activation energy of the pyrolysis of CNS and PS was 175.2 and 208.9 kJ/mol, respectively. Friedman and Flynn-Wall-Ozawa iso-conversional methods were applied and the results were found to be consistent with the models. To express the presence of complex reaction mechanisms and the interactions of the radicals, thermodynamic parameters were also calculated. Finally, the pathways for main volatiles were established, and their relationship with the pyrolytic degradation was suggested.     

Pyrolysis of mixed plastics for the recovery of useful products

Thermal and catalytic pyrolysis of polystyrene (PS) with low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), poly-ethylene terephthalate (PET) plastics were carried out in a 25 cm³ stainless steel micro reactor at around 430–440 °C under 5.5–6.0 MPa of N₂ gas pressure for 1 h. Three reactions of each plastic with PS were conducted in the ratio of 1:1, 1:2 and 1:3. The amount of PS was varied to explore its role and reactivity. In all coprocessing reactions, ratio 1:1 afforded the best yields in the form pyrolytic oils. SIM distillation of hexane soluble portion showed that the low boiling fractions were not found and fractions were obtained only after 96 °C + boiling point. It could be due to the vaporization of high volatile components. In most of the binary pyrolysis, light cycle oil (LCO) fractions have low recovery than heavy cycle oil (HCO). GC identified some very important chemical compounds present in the liquid products obtained from the pyrolysis of mixed plastics. The results obtained from this study have shown usefulness and feasibility of the pyrolysis process of the mixed plastics as an alternative approach to feedstock recycling.     

Hydropolysilanes as precursors to silicon carbide

A systematic study of the roles of three different types of monomers and their compositions in hydropolysilane homo-, co-, and terpolymers on their pyrolytic yields to silicon carbides was performed. The diorganodichlorosilane monomer, serving to increase molecular weights of the polymers, is not a significant factor in pyrolytic yields. The organotrichlorosilane monomer, leading to branched structures of the polymers, is helpful in obtaining high pyrolytic yields. The monoorganodichlorosilane monomer, providing crosslinking sites for the polymers, is useful in retarding decomposition during pyrolysis. The precursor-to-ceramic conversion chemistry was studied using thermogravimetry, infrared spectroscopy, X-ray powder diffraction, and Rutherford backscattering spectrometry. The pyrolytic yields were not pyrolysis-time-dependent but decreased as the pyrolysis temperature increased. The apparent crystalline size increased as both the pyrolysis time and temperature increased. For a 30 min pyrolysis, the pyrolysis temperature must be over 1000–1200°C to provide a crystalline pyrolytic residue. © 1995 John Wiley & Sons, Inc.     

The influence of the waste ethylene vinyl acetate copolymer on the thermal degradation of the waste polypropylene

The pyrolysis of the waste polypropylene (PP), the waste ethylene vinyl acetate copolymer (EVA) and their blends has been carried out in a fixed bed reactor at 500 °C. The effect of different ratios of the waste EVA in the waste PP/EVA blends on the thermal degradation of the waste PP was investigated in terms of both product distributions and liquid fuel properties. The compositions of pyrolysis products were characterized in detail. The liquid products from the pyrolysis of the waste PP, the waste EVA and their blends were analyzed using different analytical techniques and fuel properties of pyrolytic liquids were investigated in comparison with commercial diesel. There were no synergistic effects between products from the waste PP and products from the waste EVA. While the ratio of the waste EVA increased in the waste PP/EVA blends, aromatic content of the pyrolytic liquids increased and subsequently paraffinic content of the pyrolytic liquids decreased. In addition, the boiling point distributions of pyrolytic liquids derived from the waste PP/EVA blends were found to be similar for all tested ratios of the waste PP/EVA blends.     

废轮胎热解炭黑的研究进展

热解发黑作为废轮胎热解的关键产物,其品质较差,达不到使用要求,而且会对环境造成二次污染.主要介绍了废轮胎热解炭黑常用的分析表征方法,对热解炭黑的活化改性及再利用途径进行综述,旨在提高其利用价值.     

不同热解方式下长焰煤的热解特性研究比较

为提高长焰煤热解转化率,研究其热解过程和机理,采用格金干馏设备、固定床和间歇蒸气流化床3种不同热解装置,分别进行长焰煤的低温热解实验。研究结果表明,格金干馏实验中液体产率较高;在固定床低温热解装置中,煤颗粒达到完全热解需要的时间长,热解气体产物中氢气的产率高;在间歇蒸气流化床中,煤颗粒的热解反应速度快,但受热解过程中流化气吹损的影响,半焦产率低;热解气体的组成和分布也随热解气氛而改变,在水蒸气气氛条件下,水蒸气可能参与大分子烃类物质的部分反应,热解气体中CH4和C2以上小分子烃类物质CmHn总含量降低,CO2和CO含量增高。     

稻壳热解油的特性

利用自行搭建的固定床热反应器对稻壳进行热解实验制备热解油, 采用两种不同极性的石英毛细柱对收油后的二氯甲烷溶液进行GC-MS检测。实验结果表明:热解终温对热解油品的组分种类几乎无影响, 但热解油产率随热解终温增大呈先升高后降低趋势;热解油二氯甲烷溶液的水相部分化合物种类相对较少, 主要物质为甲酸、乙酸和1-羟基-2-丙酮, 油相部分有机物种类极为复杂, 主要物质为糠醛、糠醇以及酚类和酮类物质;可凝结的热解有机气体主要在500～600℃发生二次裂解;对稻壳600℃热解油油相检测时发现:在RTX-5MS柱检测条件下, 组分中前5种化合物是糠醛、2-丁酮、乙酸、苯酚和2-甲氧基苯酚, 而在RTX-WAX 柱检测条件下, 前5种化合物是苯酚、2-甲氧基苯酚、4-乙基苯酚、乙酸和3-甲基苯酚。     

含硅芳炔树脂热裂解行为及动力学

用热失重法(TGA、DTG)分析了含硅芳炔树脂固化物的热裂解动力学,并用Kissinger和Ozawa法计算出含硅芳炔树脂固化物的热裂解的表观活化能分别为149kJ/mol和153kJ/mol,热裂解反应近似于一级反应,据此建立了热裂解的动力学模型。用热裂解-气相色谱-质谱联用(Py-GC-MS)方法对含硅芳炔树脂的热裂解气相产物进行了分析,在热裂解过程中,主要有甲烷、氢气、乙烷、乙烯、水等气体放出。用拉曼光谱、X-射线衍射等分析了含硅芳炔树脂固化物热裂解的残留物结构,残留物是以无定型碳、石墨、SiC为主要成分的陶瓷化结构。     

Evaluation of two different scrap tires as hydrocarbon source by pyrolysis

The main objective of the present study is to investigate the effect of the polymer types in scrap tires on the pyrolysis products. Two different types of scrap tires (passenger car tire, PCT and truck tire, TT) have been pyrolyzed in a fixed bed reactor at the temperatures of 550, 650 and 800 °C under N₂ atmosphere. Pyrolysis products (gas, oil and carbon black) obtained from PCT and TT were investigated comparatively. The gaseous products were analyzed by GC–TCD. The psychical and chemical properties of pyrolytic oils were characterized by means of GC–FID, GC–MS, ¹H NMR. In addition, boiling point distributions of hydrocarbons in pyrolytic oils were determined by using simulated distillation curves in comparison with commercial diesel fuel. The production of activated carbon from pyrolytic carbon blacks (CBp) was also carried out. The composition of gaseous products from pyrolysis of PCT and TT were similar and they contained mainly hydrocarbons (C₁–C₄). Pyrolytic oils were found lighter than diesel but heavier than naphtha. The physical properties of pyrolytic oils from PCT and TT were similar at the same temperature. However, the composition of aromatic and sulphur content from pyrolysis of PCT was higher than that of TT. Furthermore, TT derived pyrolytic carbon black was found more suitable for the production of activated carbon due to its low ash content.     

生物质玉米芯热解机理研究

利用热重分析方法对生物质玉米芯在不同条件下热解行为进行了详细研究 ,得出了影响热解过程的因素及热解动力学参数 (如表观活化能、反应级数及指前因子等 ) .结果表明 ,所选保护气的种类对热解过程基本上不产生影响 ;同在较低的气体流速下进行热解相比较 ,在较高的流速下进行热解 ,发生分解反应需要较高的起始分解温度、最大分解速率的温度及较高的反应活化能 ,反应级数也大 ;随着加热速率的增大 ,发生分解反应的最大分解速率的温度向高温处移动 ,但反应的活化能降低 ,反应级数减小 .在实际的热解过程中 ,采用快速加热、低流速的惰性保护气进行热解 ,有利于利用热解过程的各种产物 .