Pyrolysis of scrap tire rubbers: Relationships of process variables with pyrolysis time

The functional relationships of industrially interesting variables such as pyrolysis temperature, heating rate, and sample size with pyrolysis time were explored to provide basic information on designing energy efficient processes. Pyrolysis kinetics of scrap tire rubbers tested in this study were investigated to formulate the functional relationships of pyrolysis temperature and heating rate. The pyrolysis time decreases exponentially with increasing pyrolysis temperature and heating rate, indicating high activation energies of pyrolysis reaction of the scrap tire rubbers tested in this study. The effect of heat transfer on the pyrolysis kinetics was evaluated by seeking the functional relationship between the sample size and pyrolysis time.The pyrolysis time increases linearly with increasing sample diameter. The slope of the straight line is proportional to the specific heat of the sample.     

Pyrolysis of wood at high temperature: The influence of experimental parameters on gaseous products

The pyrolysis of wood was carried out in an Entrained Flow Reactor at high temperature (650 to 950 °C) and under rapid heating conditions (> 10³ K s^− 1). The influence of the diameter and initial moisture of the particle, reactor temperature, residence time and the nature of the gaseous atmosphere on the composition of the gaseous products has been characterised. Particle size, between 80-125 and 160-200 μm, did not show any impact. Pyrolysis and tar cracking essentially happen in very short time period: less than 0.6 s; the products yields are only slightly modified after 0.6 s in the short residence times (several seconds) of our experiments. Higher temperatures improve hydrogen yield in the gaseous product while CO yield decreases. Under nitrogen atmosphere, after 2 s at 950 °C, 76% (daf) of the mass of wood is recovered as gases: CO, CO₂, H₂, CH₄, C₂H₂, C₂H₄ and H₂O. Tests performed under steam partial pressure showed that hydrogen production is slightly enhanced.     

Pyrolysis and reuse of tire casings

The addition of pyrolytic slag obtained from tire casings to coking batch is considered, along with methods of processing rubber goods and the products obtained. Analysis of the pyrolytic liquid indicates that its addition to coal batch will yield metallurgical coke of normal strength.     

The influence of processing variables on the wetting properties of a hydrophobic powder

The aqueous wetting properties of samples of a hydrophobic powder (griseofulvin) prepared by crystallisation, controlled precipitation, dry grinding and wet grinding have been assessed by two methods in terms of a contact angle, θ. The first employs drop formation on the surface of compacted powder, previously saturated with solution, while the second employs extrapolation of the quantity, cos θ, obtained for penetration of ethanol—water mixtures into powder beds, to zero mole fraction of ethanol concentration. Both methods establish that a difference exists in the surface properties of the different samples of powder and this appears to be a function of the process rather than the batch of powder. The two methods give significantly different values for the aqueous contact angle, which appears to be related to the actual nature of angle measured. The value derived from liquid penetration appears to provide a better reflection of the properties of the powder samples.     

浅谈成型设备的性能与操作对胎坯质量的影响

从胎坯成型所用设备的性能和操作对胎坯质量的影响进行了阐述。着重介绍了成型机的结构、分类及经常出现的质量缺陷、造成的原因和防治办法。对胎坯的生产具有一定的参考价值。     

浅谈硫化设备的性能与操作对外胎质量的影响

本文首先介绍了外胎硫化前胎坯、工艺条件、工装设备、硫化介质及动力等的准备工作及应注意的事项，然后对双模定型硫化机、硫化罐、四立柱硫化机等3种常见硫化设备的结构性能、硫化轮胎时的操作过程及各种注意事项、各种常见故障的处理等作了详细的分析。最后分析了几种硫化设备的优缺点，认为正确的操作能够在一定程度上弥补设备性能的不足。     

轿车胎胶芯工艺控制及其对成品均匀性的影响

针对轿车轮胎三角胶芯的压出、贴合与接头工艺对胶芯部件乃至整体轮胎均匀性的影响进行了分析。指出在符合工艺规范的前提下,压出工艺对均匀性影响最大的因素是停顿点的出现,将使对应的胶芯局部质量偏低;贴合工艺中现行采用的贴合与旋转拉伸同步进行的工艺方法是导致均匀性波动的主要原因,若采用先接头再整体同步贴合成型的工艺方法将使均匀性获得明显改善;而接头工艺采用双刀裁断对均匀性的影响则利弊并存,较之单刀裁断整体上并无优势。     

我国轮胎工业的发展及其对世界轮胎工业的影响

论述我国轮胎工业的发展及其对世界轮胎工业的影响。我国已形成了比较完整的轮胎工业体系,子午线轮胎产量和质量不断提高,轮胎生产进入世界前列,轮胎耗胶量居世界第1位。我国内外资企业共同发展、我国成为轮胎制造基地、我国轮胎出口不断增长以及我国推出十大名牌轮胎均对世界轮胎工业构成了影响。我国轮胎工业面临新一轮技术革命,需要加大科研投资、国际交流与合作、选用先进轮胎生产装备的力度。     

Polypropylene–waste ground rubber tire powder microcellular composites: Effect of processing variables on morphology and physico‐mechanical properties

Microcellular composites made from polypropylene and waste ground rubber tire powder using azodicarbonamide as chemical blowing agent have been investigated. A small quantity of SEBS‐g‐MA has been added as compatibilizer. The effect of variation in processing variables such as pressure, heating time, and operating variables such as blowing agent and crosslinker concentrations have been investigated to establish a relationship between the structure and morphology of the microcellular composite and ultimate performance characteristics such as tensile strength, tear strength, and elongation at break. The results indicate that both processing and operating variables have tremendous effect on the morphological features such as average, minimum, and maximum cell size as observed from scanning electron microscopy. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

废旧轮胎胶粉的加工及改性

采用常温法用自主开发的WTPS小型实验室胶粉加工系统可得到80目细度的胶粉，系统提供超声波和臭氧活化处理功能，经活化的胶粉粒子表面活性增加，可改善胶粉颗粒与基质材料的粘合。描述了胶粉制作约减震轨枕垫，已应用于韩国高速铁路，效果良好。     

Pyrolysis/gasification of agricultural residues by carbon dioxide in the presence of different additives: influence of variables

Pyrolysis/gasification of grape and olive bagasse by CO₂ under different experimental conditions has been studied. Variables investigated were particle size, temperature, type and concentration of additive and chemical washing with sulfuric and phosphoric acid solutions. Compounds like H₂, CH₄, CO and methanol, acetone, furfuryl alcohol, furfural, naphthalene, phenol and o-cresol were identified as components of gas and liquid fractions obtained from pyrolysis/gasification processes. Particle size had no influence, while temperature was a significant variable yielding increases of fixed carbon and gas content. In most of cases, a temperature between 600 to 700°C lead to a maximum liquid production. The principal additive used was ZnCl₂, concentration of this salt exerted a positive effect on hydrogen production, about 5 to 8 times higher than that obtained in the absence of additive. As far as structural characteristics of activated carbon are concerned, the increase of temperature, ZnCl₂ and acid solution concentrations (during chemical washing) lead to an increase of the specific surface area.     

The pyrolysis of scrap automotive tyres: The influence of temperature and heating rate on product composition

Shredded automotive tyre waste was pyrolysed in a 200 cm³ static batch reactor in a N₂ atmosphere. The compositions and properties of the derived gases, pyrolytic oils and solid char were determined in relation to pyrolysis temperatures up to 720 °C and at heating rates between 5 and 80 °C min⁻¹. As the pyrolysis temperature was increased the percentage mass of solid char decreased, while gas and oil products increased until 600 °C after which there was a minimal change to product yield, the scrap tyres producing approximately 55% oil, 10% gas and 35% char. There was a small effect of heating rate on the product yield. The gases were identified as H₂, CO, CO₂, C₄H₆, CH₄ and C₂H₆, with lower concentrations of other hydrocarbon gases. Chemical class composition analysis by liquid chromatography showed that an increase in temperature produced a decrease in the proportion of aliphatic fractions and an increase in aromatic fractions for each heating rate. The molecular mass range of the oils, as determined by size exclusion chromatography, was up to 1600 mass units with a peak in the 300–400 range. There was an increase in molecular mass range as the pyrolysis temperature was increased. FT-i.r. analysis of the oils indicated the presence of alkanes, alkenes, ketones or aldehydes, aromatic, polyaromatic and substituted aromatic groups. Surface area determination of the solid chars showed a significant increase with increasing pyrolysis temperature and heating rate.     

设备的性能与操作对轮胎质量的影响

从轮胎生产的各工序分析了设备的性能与操作对轮胎质量的影响。认为要保证轮胎质量,既要有性能稳定的生产设备和适宜的工艺条件,更要保证正确的操作;正确的操作可以弥补设备某些方面的不足,不合理的操作则会掩盖设备优良的性能。     

论活络模具对轮胎胶边的影响

在轮胎硫化过程中很容易产生轮胎胶边,它不仅影响轮胎的外观质量,而且严重的还会影响轮胎的动平衡。子午线轮胎尤其是高档乘用轮胎,对胶边的要求非常严格,甚至有的轮胎厂为了杜绝胶边产生,曾经发起过“胶边革命”。可见胶边对轮胎生产商来说是多么的重要。是什么原因导致轮胎在硫化过程中产生胶边的,又为什么屡禁不绝呢?经过我们多年的生产实践摸索,对轮胎硫化产生胶边的原因有了一定的认识。     

Influence of elemental composition on carbonization: Pyrolysis of kerosene shale and kuckersite

Following a previous paper devoted to medium and highly oxygenated products, pyrolysis under inert atmosphere of hydrogen rich and oxygen very poor materials has been studied. Techniques used were conventional transmission electron microscopy, differential thermal analysis, thermogravimetry and IR spectrometry. Materials studied (kerosene shale and kuckersite) were natural ones but they can be considered as models for other products, provided that their elemental composition are similar. During heat-treatment, oxygen poor materials at first soften (H/C < 0.9), a largely extended parallel molecular orientation appearing at the end of the tar's departure (H/C < 0.7). The data here obtained are compared to those for oxygen richer materials. As the oxygen content increases or as they are experimentally cross-linked by oxygen, softening tends to disappear and the extent of molecular orientation decreases from a few thousand angströms to less than 100 Å. On the contrary, if tar retention is favoured by increase in pressure, autohydrogenation occurs and molecular orientation develops. General behaviour of carbonaceous materials only depends on the antagonistic equilibrium between oxygen and hydrogen.     

有氧再生废轮胎橡胶粉的制备与表征

在管式炉中对废轮胎橡胶粉进行了有氧再生,并考察了气氛、再生温度和再生时间对废轮胎橡胶粉有氧再生过程的影响。结果表明,有氧条件下橡胶粉的质量损失和溶胶质量分数均随温度升高而增大,溶胶中合成胶分子链之间易发生二次重组再交联反应,天然橡胶分子链则主要发生断裂。240 ℃下橡胶粉在有氧条件下再生10 min时,溶胶质量分数达55.9%。橡胶主链和交联键断裂主要发生了氧化反应,生成含羰基和亚砜基的化合物,同时伴有水和二氧化碳等生成,说明橡胶粉中的橡胶分子链有效断链。     

引入多元变量对摩托车轮胎外直径公差的影响

讨论引入多元变量对摩托车轮胎外直径公差的影响.参照〈欧洲轮胎轮辋技术组织工程设计手册〉引入多元变量修订的新胎充气外直径公差,与GB/T 2983-1997比较有如下变化,代号表示系列：Dn（轮辋名义直径代号）≥13,大部分规格（特别是轮胎名义断面宽2.75及以上规格）加严;Dn≤12,全部规格均放宽;公制系列：Dn≥13的规格中,轮辋名义直径小、系列高、名义断面宽大的规格放宽,反之则加严;Dn≤12,除个别名义断面宽较小的规格加严外全部放宽;轻便型系列：除2-22规格外全部放宽.     

再生活化剂420与活化体系并用对废胶粉再生效果的影响

分别研究了氧化锌、硬脂酸和硬脂酸锌对用420作再生活化剂时废胶粉再生胶结构与性能的影响。结果表明,添加硬脂酸对废胶粉的再生效果有明显的促进作用;随着硬脂酸用量的增加,再生胶的溶胶含量先增加后降低,交联密度逐渐降低,门尼黏度明显下降,并且停放30 d后门尼黏度的增加值呈减小趋势;再生硫化胶的拉伸强度和扯断伸长率增大。综合考虑硬脂酸用量为0.9-1.2份（质量）时再生胶的综合性能较好。     

Fluidized bed pyrolysis of HDPE: A study of the influence of operating variables and the main fluidynamic parameters on the composition and production of gases

In the present work, a preliminary study of the pyrolysis process of high density polyethylene (HDPE) in a fluidized bed is investigated in order to determine the influence between the fluidynamic properties of the bed reactor and the amount and composition of the gases produced. As is known, fluidized bed technology is a very interesting option to apply in the pyrolysis field due to i) the lack of moving parts in the hot region that facilitates the maintenance of equipment, ii) the high surface area to volume ratio available in the bed, and iii) the high heat transfer coefficient reached which governs the reaction products. But, heat and mass transfer coefficients are strongly affected by the fluidynamic properties of the bed.During the pyrolysis of HDPE, a fluidynamic characterization of the bed particles that consist of char-coated sand of HDPE has been carried out. Parameters such as the minimum fluidizing velocity (u_mf), terminal velocity (u_t), bed height (h_f), bed voidage (ε_f), fraction of the bed occupied by bubbles (δ), bubble diameter (d_b), bubble velocity (u_b), the mass transfer coefficients between the bubble and the cloud (K_bc) and between the cloud and the emulsion (K_ce) were determined. Subsequently, the influence of major operating variables and the fluidynamic parameters on the composition and the gas yield of the pyrolysis of HDPE were studied.     

轮胎带束层结构变化对固有频率的影响研究

分别采用有限元方法和试验方法对9种不同的带束层结构进行了固有频率的仿真计算和试验测量,通过仿真结果和试验结果的对比,不但验证了有限元仿真方法的可靠性,而且基本理清了带束层帘线材质、帘线角度、宽度对轮胎固有频率的影响,为轮胎固有频率的研究提供了可靠的仿真计算方法。