Growth and coalescence of mesophase in pitches with carbon black additives and in coal

The techniques of polatized light optical microscopy and of washing the surfaces of solid pyrolysis products with chloroform prior to SEM examination are used to monitor the growth and coalescence of growth units of mesophase in a petroleum pitch, a coal extract and a caking coal. Additions of 1 wt% of carbon black retard growth and coalescence and promote clustering of these units because of adhesion of carbon black particles. This has the effect ultimately of reducing the size of the optical texture in coke from the coal extract, but not with coke from the petroleum pitch which has lower viscosity. With the coal, mesophase growth units tend to form clusters and do not coalesce. Mesophase can form an anisotropic skin on the inside of developing pores (bubbles) in the fluid phase and this may limit their growth.     

Formation of mesophase in coal tar pitches. Influence of pyrolytic carbon particles

Hitherto it has been considered that the pyrolytic particles present in pitch as a result of high temperature cracking accelerate the formation of mesophase by the nucleation process. It has been demonstrated by optical and hot stage microscopy that the contrary is the case. The pyrolytic particles in pitch retard the development of mesophase so that mesophase starts to be detectable only at higher temperatures of pyrolysis and the coalescence is suppressed or even prevented by pyrolytic particles surrounding the mesophase spheres originally formed.     

宁武煤和废塑料的共处理液化研究

在 50mL的小型反应器内 ,进行了煤和废塑料共液化处理的研究 ;结果表明 ,废塑料在一定的条件下 ,可有效地促进煤的转化 ,提高转化率 ,降低氢耗量 ,缓和反应条件     

废塑料在炼焦配煤中的应用研究

介绍了宁钢应用塑料型煤技术,在满足焦炭质量要求的前提下,扩大了炼焦煤中添加废塑料的比例,而且在限定废塑料添加比例的条件下稳定了焦炭质量,为科学、合理、经济地治理白色污染提供了理论依据和工业经验。     

Catalytic coprocessing of coal and petroleum residues with waste plastics to produce transportation fuels

Coprocessing reactions with waste plastics, petroleum residues and coal were performed to determine the individual and blended behavior of these materials using lower pressure and cheaper catalysts. The plastic used in this study was polypropylene. The thermodegradative behavior of polypropylene (PP) and PP/petroleum residues/coal blends were investigated in the presence of solid hydrocracking (HC) catalysts. A comparison among various catalysts has been performed on the basis of observed temperatures. The higher temperatures of initial weight loss of PP shifted to lower values by the addition of petroleum residues and coal. The catalysts were also tested in a fixed-bed micro reactor for the pyrolysis of polypropylene, petroleum residues and coal, alone and blended together in nitrogen and hydrogen atmosphere. High yields of liquid fuels in the boiling range 100-480 °C and gases were obtained along with a small amount of heavy oils and insoluble material such as gums and coke. The results obtained on the coprocessing of polypropylene with coal and petroleum residues are very encouraging as this method appears to be quite feasible to convert plastic materials into liquefied coal products and to upgrade the petroleum residues and waste plastics.     

Basic study on separate charge of coal and waste plastics in coke oven chamber

Nippon Steel Corporation started to operate a waste plastic recycling process using coke ovens at Nagoya and Kimitsu Works in 2000 and at Yawata and Muroran Works in 2002. Now the total capacity is 120,000 tons per year and the recycling process is operating smoothly. In this process, coals and added plastics are carbonized and changed into coke, tar, oil and coke oven gas in a coke oven chamber. At present, upper limit of the addition rate of waste plastics to blended coals is 1% so that the plastic addition does not affect coke strength. However, the amount of waste plastics in Japan is as much as about 10 million tons per year and there is a real need for increasing the amount of waste plastics treated by the waste plastic recycling process using coke ovens. We investigated a method of increasing the addition rate of waste plastics without affecting coke strength by charging coal and plastic separately in a coke oven chamber. In the case of the same plastic addition rate, charging the plastic in the bottom or the top part of the coke oven chamber can decrease the deterioration of coke strength compared with charging a homogeneous mixture of coal and plastic. Charging the plastic in the bottom decreases the coke strength to a greater extent than charging the plastic in the top. This is because the decomposition of the plastic charged in the bottom decreases the bulk density of the upper coal layer. The results suggest that charging the coal and waste plastics separately increases the amount of waste plastics treated in the waste plastic recycling process using coke ovens. In order to commercialize this method, further studies are necessary concerning the charging method, device and the effect of this method on the coke oven operation.     

Rheological characteristics of coal tar and petroleum pitches with and without additives

An extensive study of rheological characteristics of coal tar and petroleum pitches with and without additives, namely, petroleum coke, natural graphite and carbon black has been made. It is found that all pitches, pure or mixed with a carbon additive are not Newtonian as reported in the literature, but behave Theologically as Bingham plastics with certain yield stress and plastic viscosity at all temperatures of measurement between 85–180°C. The yield stress and plastic viscosity both decrease with increase in temperature of the pitch. A pure petroleum pitch having the same softening point as that of a coal tar pitch is found to have a lower viscosity compared to that of the latter at all temperatures of measurement. This suggests that the criterion of softening point as a measure of suitability of a coal tar pitch binder in the manufacture of artificial carbon is not sufficient for petroleum pitches. Addition of ten parts of carbon black by weight of pitch results in a considerable decrease in viscosity change with temperature of the coal tar pitch compared to almost insignificant change in the case of the petroleum pitch of the same softening point. However, the addition of petroleum coke or natural graphite makes the pitch more viscous but does not change the temperature dependence of viscosity of either of the two types of pitches. The implications are discussed.     

Interaction of thermosetting plastics with clinkering coal

The influence of phenol-formaldehyde resin on the clinkering properties of coal batch is studied by means of the dilatometric method proposed by the Institute of Mining and Dnepropetrovsk Metallurgical Institute. For comparison, its influence on the clinkering ability is studied by the Roga method. The results show that this organic additive has a similar influence in both cases.     

废旧塑料的回收与利用

综述了利用区块链技术进行废旧塑料的回收.使用区块链技术建立的塑料银行可以激励人们自发地回收废旧塑料.废旧塑料的回收流程大多是线下的,监管困难,使用区块链技术可以使用户在区块链上查询全流程的回收数据,便于监管.在废旧塑料的分选和利用方面,介绍了聚乙烯和聚丙烯的分选,聚对苯二甲酸乙二酯与聚氯乙烯混合固体塑料的分选.废旧塑料...     

Re-use and separation of waste plastics

Commercial and pilot-scale methods for the re-use of clean, unmixed scrap plastic are described. Mixed scrap presents greater problems and efforts have been made to improve its properties with additives or by altering its composition. Separation methods are surveyed. Mixed wastes find limited re-use in low quality products. Re-use of waste plastics as fuel is now probably the most economical alternative. Economic rather than technical obstacles remain for this recycling.     

Pyrolysis-gasification of plastics, mixed plastics and real-world plastic waste with and without Ni-Mg-Al catalyst

Polypropylene, polystyrene, high density polyethylene and their mixtures and real-world plastic waste were investigated for the production of hydrogen in a two-stage pyrolysis-gasification reactor. The experiments were carried out at gasification temperatures of 800 or 850 °C with or without a Ni-Mg-Al catalyst. The influence of plastic type on the product distribution and hydrogen production in relation to process conditions were investigated. The reacted Ni-Mg-Al catalysts were analyzed by temperature-programmed oxidation and scanning electron microscopy. The results showed that lower gas yield (11.2 wt.% related to the mass of plastic) was obtained for the non-catalytic non-steam pyrolysis-gasification of polystyrene at the gasification temperature of 800 °C, compared with the polypropylene (59.6 wt.%) and high density polyethylene (53.5 wt.%) and waste plastic (45.5 wt.%). In addition, the largest oil product was observed for the non-catalytic pyrolysis-gasification of polystyrene. The presence of the Ni-Mg-Al catalyst greatly improved the steam pyrolysis-gasification of plastics for hydrogen production. The steam catalytic pyrolysis-gasification of polystyrene presented the lowest hydrogen production of 0.155 and 0.196 (g H₂/g polystyrene) at the gasification temperatures of 800 and 850 °C, respectively. More coke was deposited on the catalyst for the pyrolysis-gasification of polypropylene and waste plastic compared with steam catalytic pyrolysis-gasification of polystyrene and high density polyethylene. Filamentous carbons were observed for the used Ni-Mg-Al catalysts from the pyrolysis-gasification of polypropylene, high density polyethylene, waste plastic and mixed plastics. However, the formation of filamentous carbons on the coked catalyst from the pyrolysis-gasification of polystyrene was low.     

废旧塑料的综合利用

综合利用废旧塑料,解决“白色污染”,已成为全球的研究热点。本文从废旧塑料的直接利用、改性利用、热分解、与煤共液化等几个方面综述了废旧塑料的综合利用途径,其中废旧塑料与煤共液化处理技术很有发展前途,将成为今后研究的新热点。     

Thermal decomposition of petroleum and coal tar pitches by thermogravimetry

Thermogravimetry was used to investigate petroleum and coal tar pitches undergoing pyrolysis in an atmosphere of air and nitrogen at three different heating rates. Pyrolysis of pitches in air is a three-stage process, whereas in nitrogen two stages were found. A kinetic analysis of the thermogravimetric data has been made. The orders and activation energies have been determined for each stage of decomposition using the methods of Kissinger, Freeman, and Hüttinger.     

用废聚苯乙烯泡沫塑料制备涂改液

将废聚苯乙烯泡沫塑料溶解在乙酸乙酯中,制成高分子胶粘液,向其中加入表面活性剂十二烷基硫酸钠、增塑剂邻苯二甲酸二丁酯和遮盖剂氧化锌、二氧化钛,经球磨机研磨制成涂改液。通过控制变量法,探讨了各组分对涂改液性能的影响,确定了制备涂改液的最佳配方。该法工艺简单,操作方便,不需要特殊设备,且变废物为原料,既降低了产品的成本,减少了涂改液对人体的毒害性,又对减轻白色污染的危害作了有益的探索。     

废旧塑料分选技术

废旧塑料的回收包括 3个阶段 :收集、分选、加工或再生等步骤。只有清洁的废旧塑料才能生产高质量的产品 ,这需要有效的塑料分选方法。评述了光选、电选、风力分选、密度分选、浮选等废旧塑料分选技术 ,指出浮选在废旧塑料分选方面具备独特优势     

Liquid-phase methanol synthesis in apolar (squalane) and polar (tetraethylene glycol dimethylether) solvents

The kinetics of the three-phase methanol synthesis over a commercial Cu–Zn–Al₂O₃ catalyst were studied in an apolar solvent, squalane and a polar solvent, tetraethylene glycol dimethylether (TEGDME). Experimental conditions were varied as follows: P=3.0–5.3 MPa, T=488–533 K and Φ_vG/w=7.5×10⁻³–8×10⁻³ Nm³ s⁻¹kg⁻¹_cat. The nature of the slurry–liquid influences the activation energy and the kinetic rate constant by interaction between adsorbed species and solvent and by competitive adsorption of the solvent on the catalyst surface. The rate of reaction to methanol observed in TEGDME appeared to be about 10 times lower than in squalane. TEGDME reduces the reaction rate, which is a disadvantage for its use as a solvent.     

用废旧橡胶改性塑料技术的研究进展

综述了废橡胶改性塑料的几种方法,介绍了废胶粉的改性与共混反应增容技术的发展状况和废橡胶改性塑料技术的应用有有关流变、形态、粒径、界面等方面的理论研究进展。     

利用废杂塑料制备燃料油

为使废杂塑料的产物回归石油产品，介绍了废杂塑料制备燃料油工艺中原料的分离、原料的预处理、催化剂的使用以及热分解、裂解工艺条件。     

CO2 reforming of waste plastics

Carbon dioxide reforming of polyethylene was carried out. Pyrolysis and catalytic carbon dioxide reforming were combined. Polyethylene was packed at the bottom of the reactor and the catalyst, Pd/Al₂O₃, was packed at the top of the reactor. The pyrolysis of the polyethylene occurred at the bottom of the reactor, and the pyrolysis products reacted with carbon dioxide on the catalyst bed. Carbon dioxide reforming occurred on the catalyst bed zone. Hydrogen, carbon monoxide, methane, ethane, ethene were produced at 910 and 720 K which were the catalyst and polyethylene temperature, respectively. Polyethylene was completely reformed to carbon monoxide and hydrogen when catalyst temperature was increased or polyethylene temperature was decreased.