聚丙烯在超临界水中的降解反应初探

超临界水由于具有许多独特的性质,用超临界水作为化学反应的介质已受到人们广泛的重视,尤其是它可以使废塑料发生降解或分解。本文以聚丙烯在超临界水中的降解作为模型反应．研究了温度、压力、时间及水／聚丙烯等条件对该反应的影响,为今后聚丙烯及其它塑料废弃物在超临界水中的降解提供实验指导。     

核电站废弃离子交换树脂减容化处置技术研究现状

近年来,核电站废弃离子交换树脂的减容化处置成为国内外研究的热点。综述了核级废弃离子交换树脂减容化处理技术,包括酸消化法、芬顿湿式氧化法、等离子氧化技术和超临界水氧化技术的反应原理、方法特点、减容性、降解率、影响因素以及安全环保等方面。同时对这4种技术进行列表对比,通过各个方法的减容性、安全性以及高效性结合它们的优缺点,认为超临界水氧化法处理离子交换树脂是当前较为可行的方案之一,并对超临界水氧化技术实现工程化应用待解决的关键问题进行展望。以期为核级废弃离子交换树脂的减容化处置提供借鉴和参考。     

混杂废塑料的化学回收

混杂废塑料的化学回收１．化学回收将成为废塑料公害综合治理的重要手段欧洲废包装材料处理法就要求回收的数量而论是世界同类立法中最严格的。但是，这样严格的立法由于规定回收数量庞大，也暴露了机械回收法不足以按立法要求的水平回收使用后的混杂废塑料的弱点。化学回...     

废弃塑料的回收再利用技术

废弃塑料的回收再利用技术从保护地球环境出发，人们正致力于研究废弃塑料的回收再利用技术。通常废弃塑料分为一般性混杂废塑料和工业性废塑料两类，其比例大体相同。现今所研究的回收技术多半是针对工业性废塑料的，而对于来自家庭日杂用品的混杂废塑料，主要是研究改善...     

上海交大研发出超临界水氧化设备 破解水污染治理难题

正工业生产领域容易产生大量难降解高浓度废水,特别是有机毒物废水处理更是其中难啃的一块硬骨头。上海交大近日宣布,经过10年艰苦技术攻关,研发出新型难降解高浓度高毒有机废水处理技术与装备,攻克了超临界水氧化技术处理高浓度高毒难降解有机废水在产业化应用时面临的高压、堵塞、腐蚀、大型化和稳定性等一系列技术难题。一物降一物,废水中的有毒有机物也有"天敌",它就是"超临界水氧化"。利用超临界水作为特殊溶剂,水     

火电厂水平衡测算及节水回收建议

主要是对超临界空冷燃煤机组的水平衡情况进行了月度的测算和说明,并进一步提出节水回收措施建议。     

废塑料回收装备列入《指导目录》

浙江丰利粉碎设备有限公司开发了废塑料复合材料回收处理成套装备（回收率95％以上）,该设备突破了粉体化回收废塑料、高压静电分选、智能化自动控制和贵金属提取等关键技术,从而有效破解铝塑复合膜、铝塑板、塑料复合膜、     

废旧高分子材料回收利用的进展

概述了目前高分子材料的回收利用情况,在列举原有废旧聚合物回收途径的同时,详细说明了废旧聚合物回收利用的新进展,如生物侵蚀法回收废橡胶．回收橡胶与热塑性塑料的共混体,废胶粉粒子添加到水泥中,热解废塑料,塑料“再生木材”,废塑料和玻璃复合商用砖等等。     

南印度最大塑料回收工厂投产

正印度环保初创公司Ramky Enviro Engineers Limited(REEL)近日为其位于南印度的塑料回收工厂举行揭牌仪式。REEL首席执行官Satish Cheeti在揭牌仪式上表示,每年印度大约产生946万吨废塑料,其中40%的废塑料未经过回收处理。随着这家位于南印度制药城(Pharma City)的塑料回收工厂投产,REEL将能对工业废塑料和家庭消费后塑料进行预处理和升级循环,使其成为高质量的可回收塑料颗粒,     

环境保护和降解塑料

一、前言塑料的优良性能使其应用十分广泛,因此用后的废塑料也越多,这些难以处理和回收利用的“特殊垃圾”对环境的污染和危害也日趋严重,业已成为一个社会问题,引起世界各国的关注。一些国家为此提出了种种对策。例如,美国政府及一些自治州制定了各种限制使用塑料的法规;意大利政府早在1987年10月就制定了废塑料收集法,1989年各地又制定了废塑料回收、利用及处理的种种规定,乃至课税。限制塑料的使用,以减少对环境的污染,毕竟是一种消极的办法,因此人们对能在一定时     

Reactions of polymers in supercritical fluids for chemical recycling of waste plastics

Sub- or supercritical fluids have been focused as reaction media for environmental applications from a view point of green chemistry. Chemical recycling of waste plastics is important issue. We have applied reaction in water or organic solvent in sub- or supercritical condition to convert polymers into its monomers. Condensed polymers such as polyethylene terephthalate or nylon 6 were depolymerized to its monomers by hydrolysis of alcoholysis in supercritical water or alcohol. The other polymers such as phenol resin and fiber reinforced plastics (FRP) were also decomposed to small molecules by solvolysis. In this paper, the degradation of polymers studied in our group was reviewed.     

废旧塑料再利用生产新材料的研究进展

废旧塑料的回收利用作为一项节约能源、保护环境的措施,普遍受到重视.本文概述了废旧塑料的再生利用途径,着重介绍了利用废旧塑料生产建筑、涂料等新材料的方法和工艺流程,并对废旧塑料的回收利用进行了展望.     

电站锅炉烟气余热利用技术方案研究

超临界电站锅炉排烟热损失量很大,对锅炉尾部烟气余热进行回收利用可以有效提高电厂的热经济性,减少煤耗,降低环境污染。目前火电厂最广泛提高烟气余热利用效率的方式是加装低温省煤器装置。对某超临界机组锅炉余热利用技术进行研究,分析不同低温省煤器布置方案,提出采用双级低温省煤器回收电站锅炉余热利用技术方案,即采用低温烟气与低加凝结水换热技术、前置式空气预热器与低温省煤器组合的能源梯级利用方式,实现最优节能及最佳投资收益。     

Chemical recycling of plastic wastes made from polyethylene (LDPE and HDPE) and polypropylene (PP)

The recycling of either model polymers or waste products based on low-density polyethylene (LDPE), high-density polyethylene (HDPE) or polypropylene (PP) is examined using the dissolution/reprecipitation method, as well as pyrolysis. In the first technique, different solvents/non-solvents were examined at different weight percent amounts and temperatures using as raw material both model polymers and commercial products (packaging film, bags, pipes, food-retail outlets). The recovery of polymer in every case was greater than 90%. FT-IR spectra and tensile mechanical properties of the samples before and after recycling were measured. Furthermore, catalytic pyrolysis was carried out in a laboratory fixed bed reactor with an FCC catalyst using again model polymers and waste products as raw materials. Analysis of the derived gases and oils showed that pyrolysis gave a mainly aliphatic composition consisting of a series of hydrocarbons (alkanes and alkenes), with a great potential to be recycled back into the petrochemical industry as a feedstock for the production of new plastics or refined fuels.     

聚氨酯泡沫在环境领域的应用及其回收处理

总结了聚氨酯泡沫在环境领域的应用开发,包括利用聚氨酯泡沫作为水处理金属离子吸附剂、气固废吸附材料基材、废水处理用微生物载体。综述了废旧聚氨酯泡沫回收处理及利用方法,重点阐述了物理回收法、化学回收法中的醇解、水解、氨解、热解法等。最后对各类回收方法进行了总结比较。     

Study on pyrolysis of typical medical waste materials by using TG-FTIR analysis

Pyrolysis of certain medical waste materials was studied using thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TG-FTIR). Pyrolysis characteristics of three common materials were discussed. The pyrolysis of absorbent cotton turned out to be the most concentrative, followed by medical respirator and bamboo stick. From TG and DTG curves, pyrolysis of these three materials occurred in single, two and three stages respectively. Evolved volatile products from all these three materials included 2-butanone, benzaldehyde, formic acid, acetic acid, hydrocarbon, carbon dioxide, carbon monoxide, and water; whereas no sulphur dioxide, ammonia and hydrogen cyanide was detected. There are several differences in yield among them. However, the study in this paper is essential for medical waste pyrolysis model, the TG-FTIR approach is potential to provide valuable inputs for predictive modeling of medical waste pyrolysis. More studied are needed to get the kinetic parameters and pyrolysis models that can predict yields and evolution patterns of selected volatile products for CFD applications.     

Decomposition of isoquinoline and quinoline by supercritical water

The ability of supercritical water (SCW) to decompose heterocyclic compounds (quinoline and isoquinoline) has been explored in this study. The results obtained suggest that water acts as a chemical reagent above its critical point (374 degrees C and 22.1 MPa). Significant proportions of isoquinoline and quinoline were removed during the reaction with SCW. The response of these compounds to pyrolysis was also compared with their reaction with SCW. Both compounds were relatively more reactive in the presence of SCW than during pyrolysis. Because of the different positions of N atom in the two compounds, they reacted with SCW differently. Breaking of C-N bonds during SCW reaction was by hydrogenation and hydrocracking, while pyrolysis was due to thermocracking mainly.     

Comparison between supercritical carbon dioxide extraction and aqueous surfactant washing of an oily machining waste.

Mathematical models are developed to compare aqueous surfactant washing to supercritical carbon dioxide (SCCO2) extraction. These two cleaning processes are potentially competitive technologies which can be used to remove oily contaminants from a solid waste. In both processes, the cleaning efficiency for a batch of waste is evaluated by quantifying the residual oil content in the treated sample. A mass transfer model is used to simulate a semi-continuous washing process, and the experimental data, obtained in a batch operation, are used to estimate the equilibrium parameters in the model. For SCCO2 extraction, a linear desorption model is used to describe the supercritical desorption of oil from the solid phase into the CO2 phase and the simulated results agreed very well with the experimental data. The oil removal in aqueous surfactant washing is viewed to be controlled primarily by the diffusional transport of oil from the interiors of the waste elements to the surface, thus, it can be significantly affected by the size of the particles. A pre-cleaning pulverization is then recommended to improve the cleaning efficiency without increasing any other operation costs. In SCCO2 extraction, the desorption of oil from the solid waste is the controlling step and consequently, the solvent flow rate has no influence on oil removal. Our theoretical studies show that the difference between the cleaning efficiencies of these two technologies is not significant, with the oil concentration in the washing products approximately 5% lower than that in the extraction products.