PET瓶回收应用进展

介绍了国内外废旧PET瓶通过物理或化学回收方法制取再生薄片、粒料、纤维、片材、泡沫塑料、复合材料、涂料等的应用进展；另外，对于闭环循环的PET“瓶-瓶”回收工艺技术进行了专门介绍。     

废旧PET瓶盖及标签材料的分析与鉴别

文章采用DSC和FTIR方法对废旧PET瓶盖及标签进行了测试分析和鉴别,结果表明,PET瓶盖材料均为高密度聚乙烯(HDPE),测得其MI在3 g/10 min左右,表明其分子量较高,可以作为高性能HDPE材料回收使用;PET瓶标签大部分为聚丙烯(PP)材料,但仍有少部分为聚氯乙烯(PVC)改性材料。上述结果为废旧PET瓶的分类回收和高值化利用提供了基础数据。     

东丽推出聚酯瓶衍生纤维

<正>2019年9月24日,东丽株式会社在东京宣布,推出名为+的新商业纤维品牌,并表示将支持使用以回收废旧聚酯(PET)瓶为原料来源生产的纤维。东丽希望利用该品牌促进PET瓶回收,并通过提供PET瓶衍生的高附加值纤维来实现闭环经济。     

三井化学工程公司开发用回收的废旧PET制新瓶的技术

三井化学工程公司与细川微粉公司(Hosokawa Micron)合作开发了一种用回收的废旧PET瓶制新PET瓶(瓶对瓶)的新技术。这项技术已获得美国食品药物管理局(FDA)的无异议证书(即属条件B)。由于获得认可，用这种技术将回收瓶制成各种饮料的容器已成为可能，制成的容器不仅可用于装矿泉水，而且可装可乐类和其他饮料、咖啡和酱油等。该公司想利用这一技术优势，     

日本废旧PET瓶化学再生现状与课题

日本2004年PET瓶回收率达62.3%,达19.1万吨,其中企业回收率15.9%,地方自治团体(市、街、村)46.4%。2005年为17万吨,首次出现下滑。目前虽然企业回收率增加,但自治团体回收率下降,这是因为中国及中国香港等对废旧PET瓶的需求增加,带动日本废旧PET瓶出口,推测2004年日本废旧PET瓶     

废旧PET固相增黏回收工艺探索

PET材料在透明塑料领域中价格低廉,且综合性能较好,我国每年废旧PET的产生量非常大,由于PET在自然环境中很难降解,为了减少其对环境的影响,迫切需加大废旧PET的循环利用。目前废旧PET回收工艺主要有物理回收和化学回收2种。制约废旧PET循环使用的主要瓶颈是特性黏度太低,因此研究PET回收增黏工艺对提升废旧PET的回收利用,减少其对环境的影响,具有重要意义。     

废旧PET的化学回收方法研究进展

PET综合性能良好,应用广泛,但难以生物降解,随着排入自然界的废旧PET日益增多,对其进行回收利用已迫在眉睫。回收方法包括物理方法、化学方法、物理化学方法等,其中,化学回收方法将PET解聚成单体或低聚体,是实现废旧PET循环利用最有前途的途径之一,包括醇解法、水解法等。本文重点对废旧PET的化学回收方法研究现状及新进展进行了综述,旨在为PET的工业回收利用提供参考。     

近期PET系列产品循环利用新技术

介绍了PET循环利用的发展。详细叙述了近几年PET产品循环利用的新技术,包括可提高回收PET性能的新型增链剂、PET瓶-瓶回收技术,PET回收在塑料合金领域的应用,用微波炉分解PET塑料瓶,PET再生率达95%的新技术,PET废料生产PBT和聚苯乙烯新工艺,可反复使用的PET啤酒瓶等。并对PET循环利用的发展前景进行了展望。     

废旧聚酯化学回收法及其再生产物的应用研究进展

化学回收法作为一种能最大程度回收废旧聚酯(PET)以及实现其闭环回收的方法而受到广泛关注。对废旧PET的化学回收方法及其回收再生的PET在不同领域的应用进行了综述，总结了现有的化学回收工艺及其特点。最后提出未来可以从机制层面深入，将较为成熟的降解技术与新兴的技术、助剂结合，进一步提高再生产物的品质，将废旧PET变废为宝，希望为废旧PET回收技术的研究探讨提供一定的参考。     

欧洲废旧PET瓶价格有所下降

11月份，回收系统中的废旧PET瓶价格再次下降。大部分供应商和回收商称，相比10月份，德国市场每吨已下跌约20欧元。虽然工业废料“产量”也已经减少，供应方面却没有实质问题。     

天然气制油循环气脱碳活化剂和烃类损失研究

针对天然气制油（GTL）循环尾气组成在脱碳过程中对活化剂的降解损失以及烃类的损失进行了试验研究,报道了有机胺类活化剂与含氧有机气体以及烃类气体接触的降解试验数据。在模试装置上测定了原料气中烃类在GTL循环气脱碳溶剂中的损失,最高为0．69％,最低为0．08％。在溶液循环量不变的情况下,改变循环气的流量,在单位体积溶液溶解的烃类有随气量增高的趋势,但变化比较平缓,在5～8L／m3内缓慢上升。     

Supercritical fluid recycle for surge control of CO2 centrifugal compressors

This paper presents computer-based design and analysis of control systems for centrifugal compressors when the operating fluid is supercritical CO₂.It reports a non-linear dynamic model including a main forward compression line and two different configurations for the recycle antisurge line. Disturbance scenarios are proposed for testing the configurations and performance indicators are suggested to evaluate control performance and power consumption of the compression system.The paper demonstrates that compared to the hot recycle, the process configuration including a cold gas recycle has better overall stability, but higher power consumption and lower values for the control performance indicators. Based on the previous considerations, the paper gives suggestions regarding the choice of the recycle configuration. Moreover it compares subcritical and supercritical compression during surge prevention and highlights the importance of the selection of the gas recycle configuration when full recycle is needed.     

合成纤维的回收、再生、循环利用

对合成纤维废弃物要进行回收、再生,实现循环利用。发达国家已进行了大量的研究与实施工作,在技术上要解决单一材料产品的设计、材料循环、化学循环等方面的问题。我国应尽早开展合成纤维的回收、再生的系统研究工作。     

RESIDENCE TIME DISTRIBUTIONS IN A JETLOOP REACTOR

The effect of residence time, jet position, jet size, catalyst mass and temperature on the recycle ratio in a jetloop reactor using a residence time distribution model is reported. The recycle ratio goes through a maximum as residence time changes. The recycle ratio increases as jet size, catalyst mass and temperature are reduced. The optimum position of the jet is between 0 and 5 mm above the top of the central draft tube.     

废旧聚四氟乙烯的回收方法及应用

介绍了废旧聚四氟乙烯产生的原因及数量；探讨了回收利用的目的和意义。对目前国内外废旧聚四氟乙烯的回收利用的原理、方法做了比较详细的讨论；并对今后废旧PTFE的回收利用提供了一些建议和前景分析。     

Recycle effect on membrane extraction through cross-flow rectangular modules

The effects of recycle on membrane extraction through a cross-flow rectangular module have been studied both theoretically and experimentally. Theoretical analysis of mass transfer in cross-flow device with and without recycle is analogous to heat transfer in cross-flow heat exchangers. Experiments were carried out with the use of a membrane sheet made of microporous polypropylene as a permeable barrier to extract acetic acid from aqueous solution by methyl isobutyl ketone. Theoretical predictions are in agreement with the experimental results. In contrast to a device without recycle, improvement in mass transfer is achievable if cross-flow membrane extraction is operated in a device of same size with recycle which provides the increase of fluid velocity, resulting in reduction of mass-transfer resistance. It is shown that recycle can enhance mass transfer, especially for large feed-concentration solution with high distribution coefficient operated under high reflux ratio.     

A FUNDAMENTAL ANALYSIS OF CONTINUOUS FLOW BIOREACTOR AND MEMBRANE REACTOR MODELS WITH TESSIER KINETICS

In this research we analyze the steady-state operation of a continuous flow bioreactor, with or without recycle, and an idealized or nonidealized continuous flow membrane reactor. The model extends to include a fixed bed reactor where a fraction of the biomass is detached by the flow. The reaction is assumed to be governed by Tessier growth kinetics. We show that a flow reactor with idealized recycle has the same performance as an idealized membrane reactor and that the performance of a nonidealized membrane reactor is identical to that of an appropriately defined continuous flow bioreactor with nonidealized recycle. The performance of all three reactor types can therefore be obtained by analyzing a flow reactor with recycle. The steady states of the recycle model are found and their stability determined as a function of the residence time. The performance of the reactor at large residence times is obtained.     

On the limiting form of the residence-time distribution for a constant-volume recycle system

The residence-time density function for a recycle system usually tends to exponential form, with mean equal to the ratio of the volume to the volumetric flow-rate, when the recycle rate is increased at constant throughput. Two conditions each sufficient to guarantee this behaviour are: (i) that the normalized once-through residence-time density functions become independent of the recycle rate for recycle rates in excess of some finite value; or (ii) that the moments of all orders of the normalized density functions are bounded. In the former case the existence of only the zeroth and first moments for the once-through density functions is required which conditions are themselves consequences of the principle of conservation of mass. In the latter case the form of the once-through normalized density functions may change with the recycle rate. When the first n moments of the normalized once-through densities are bounded, the limits of the first n moments of system residence-time density exist and are the same as those of the exponential density function.     

MASS TRANSFER ENHANCEMENT OF CONJUGATED GRAETZ PROBLEMS IN MULTI-PASS PARALLEL-PLATE MASS EXCHANGERS WITH EXTERNAL RECYCLE

A new external recycle design at the ends of multi-pass parallel plate mass exchangers with uniform wall concentration is theoretically investigated in this study. The analytical solutions were obtained using the orthogonal expansion technique and the eigenfunction expanding in power series. The results are graphically represented. The influences of the recycle ratio, mass-transfer Graetz number, channel thickness ratio, and characteristic parameter of the permeable barrier on the mass transfer rate are presented in this study. Compared to the single-pass device, considerable mass transfer improvement is obtainable by employing the new external recycle design at both ends.     

硫酸装置尾气循环工艺

介绍Poseidon工程咨询公司开发的尾气循环工艺及相应的一转一吸和两转两吸硫酸装置流程。对影响硫酸装置设计的各种参数进行分析,给出了尾气循环工艺与传统流程在工艺条件及能源回收等方面的对比数据。结果表明,尾气循环工艺在提高总硫利用率、降低SO2及SO3排放量、降低能耗等方面具有一定的优势。