共查询到16条相似文献,搜索用时 359 毫秒
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李向辉 《再生资源与循环经济》2011,4(6):37-41
相对于填埋、焚烧等传统的处理方法,废塑料热解技术不仅可以降低塑料处理过程中对环境的污染,而且可以将废塑料还原成燃料和化学品,从而有效地回收废物资源。但是废塑料热解反应通常需要很高的温度,使得热解法回收废塑料过程变得复杂。分析比较了热解回收废塑料相对于其他方法的优势,并系统地阐述了塑料热降解的机理。在综合国内外研究的基础上提出两种低温热解废塑料的方法:加催化热解和共热解。并利用塑料降解的自由基理论,分析了催化热解和共热解法降低塑料降解温度的机理。 相似文献
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废印制线路板真空热解产物分析 总被引:1,自引:0,他引:1
在自行设计的间歇式固定床真空热解装置中热解废印制线路板(PCB),对热解产物进行了分析.在热解温度为550 ℃、热解压力为20 kPa、恒温时间为60 min的条件下,得到的热解产物质量分数为:热解渣70%;热解油3%~4%;不可冷凝热解气26%~27%.经气相色谱-质谱联用(GC-MS)分析,热解油经常压蒸馏后得到的低沸点液态油中含有29种化合物,主要有苯酚、对异丙基酚、3-乙基酚、4-甲酚及2-溴苯酚,还含有少量含溴化合物和含氯化合物.热解油经简单的蒸馏就可达到回收酚类化合物的目的.热解渣经风选可实现铜与黏附有碳黑的玻璃纤维的分离,其中铜质量分数约30%,黏附有碳黑的玻璃纤维质量分数约70%. 相似文献
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污水污泥的处理已成为令人关注的问题,传统的处理方法有许多不尽人意的地方.热解处理污泥是近年新发展的技术,其优点和可操作性受到许多研究者的关注.介绍了热解法的发展和需要解决的问题,特别介绍了国内研究较少的污泥热解的高温阶段. 相似文献
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废轮胎热解回收的产业现状与创新技术 总被引:1,自引:0,他引:1
废轮胎热解回收处理的方法以其较高的资源回收率和较低的二次污染引起广泛关注.但是废轮胎热解回收循环利用是个比较复杂的过程,尤其是热解炭黑品质和市场应用决定着整个热解过程的经济性,如果延用落后的生产工艺和简陋的热解加工设备,热解炭黑品质较差,达不到使用要求,而且还会对环境造成二次污染.主要从废轮胎热解过程和热解产物上进行了一些探索,通过在实践中改进工艺和设备,使热解炭黑的品质显著提高,旨在从技术上对日益剧增的废轮胎土法炼油有所引导,使之尽快走上工艺技术化、设备规范化的轨道,实现真正意义上的废旧轮胎循环利用. 相似文献
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介绍了燃煤电站SCR尿素热解工艺,结合当前燃料价格,通过工程案例计算,对比了各种尿素热解热源的运行费用。计算结果表明,高温蒸汽加热方案的运行费用最省,但在实际应用中受到相关条件的限制;在一定条件下,燃气加热与电加热方案是工程的优选技术方案。 相似文献
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采用热解重量分析法研究了废轮胎粉、炼焦煤粉(简称煤粉)及混合样的热解特性。实验结果表明,废轮胎粉的热解出现三个显著的失重峰,煤粉热解仅出现一个显著失重峰。与煤粉热解相比,废轮胎粉热解开始失重温度和失重基本结束的温度相对较低,失重速率较大,且失重量较大。煤粉与废轮胎粉的显著失重存在重叠的温度区间(360~450℃),说明废轮胎粉与煤粉可以进行共热解。随废轮胎粉质量分数增加,共热解物料总失重率增加。废轮胎粉与煤粉共热解存在协同效应,在280~540℃时协同效应抑制共热解挥发分的逸出,导致失重量降低,最大失重速率峰温升高;高于540℃后,协同效应促进共热解反应,使共热解总失重率增大。 相似文献
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Effect of Metal Compounds and Experimental Conditions on Distribution of Products from PVC Pyrolysis
Jatuphorn Wootthikanokkhan Adisak Jaturapiree Vissanu Meeyoo 《Journal of Polymers and the Environment》2003,11(1):1-6
Effects of heating rate, gas flow rate, and type of metal compounds on the amount of hydrogen chloride, liquid, gas, and solid pyrolyzate obtained from the pyrolysis of poly(vinyl chloride) (PVC) were investigated. The pyrolysis experiments were carried out in both a thermogravimetric analysis (TGA) instrument and a fixed-bed reactor. Products from the fixed-bed reactor were collected and analyzed by using Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectroscopy (GC-MS), titration technique, and gravimetry. It was found that heating rate in the TGA experiments did not affect the amount of released hydrogen chloride. However, the TGA profiles significantly changed with the rate. The onset of dehydrochlorination increased with the rate. In addition, as the heating rate was increased from 10 to 20°C/min, there was no solid residue left. The amount of liquid pyrolyzate obtained from the fixed-bed reactor can be either increased or decreased with the heating rate, depending on the gas flow rate and the actual residence time in the reactor. FTIR and GC-MS analysis indicated that the liquid pyrolyzates were mainly benzene, toluene, and styrene. By comparing the efficiency of various metal compounds in trapping the HCl, it was found that Ca(OH)2 was more efficient than Mg(OH)2, and that CaO was more efficient than MgO. These results are discussed in light of the reaction mechanism between HCl and the metal compounds. 相似文献
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利用热解及钙盐沉淀法对农药含钾废渣进行处理,制得高纯度的KCl.通过管式炉反应器对农药含钾废渣中有机物的去除进行了研究,探讨了升温速率、热解终温、终温保持时间及空气流量对热解过程的影响,并对钙盐沉淀法除氟过程的溶液pH及m(Ca2+)∶m(F-)进行了确定.实验结果表明:当升温速率为20℃/min、热解终温为600℃、终温保持时间为90 min、空气流量为3.0m3/min时,废渣中的有机物完全分解;钙盐沉淀法除氟的最佳条件为溶液pH 8,m(Ca2+)∶m(F-)=3.0,氟离子的去除率达到98%;最终得到KCl的产率为70.6%,产品纯度为98.2%,符合国家Ⅰ级优等品标准. 相似文献
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采用高温模拟蒸馏、红外光谱和热重分析等方法对聚乙烯副产物聚乙烯蜡进行了表征。在间歇高压反应釜中对聚乙烯副产物聚乙烯蜡进行了热解,并通过正交实验考察了热解温度、停留时间和初始压力对液相产物收率的影响。利用GC-MS技术对液相产物轻质馏分(低于200℃)进行了分析。结果表明:聚乙烯副产物聚乙烯蜡主要由长链脂肪烃(C_(14)~C_(70))组成;热解发生的温度范围为175~490℃;热解温度和停留时间是影响液相产物收率的主要因素;液相产物轻质馏分的碳数分布在C_9~C_(20),主要为α-烯烃(占比32.79%)和正构烷烃,其中单体烃含量最高的是1-癸烯(占比8.46%),它是制备高级合成润滑油聚α-烯烃的优质原料。 相似文献
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Tyre recycling has become a necessity because of the huge piles of tyres that represent a threat to the environment. The used
tyres represent a source of energy and valuable chemical products. Waste tyres were pyrolysed catalytically in a batch reactor
under atmospheric pressure. Calcium carbide was used as a catalyst to explore its effect on pyrolysis product distribution.
The effect of temperature, amount of catalyst and time on the yields of the pyrolysed products was investigated. Char yield
decreased with increase of pyrolysis temperature while total gas and liquid yields increased. The liquid fraction was obtained
with boiling point up to 320 °C. The physical and chemical properties of the pyrolysed products obtained were characterized.
The catalytic pyrolysis produced 45 wt.% aromatic, 35 wt.% aliphatic and 20 wt.% of polar hydrocarbons.
The distillation data showed that ∼80% of oil has boiling point below 270 °C which is the boiling point for 50% of distilled
product in commercial diesel oil. The oil fraction was found to have high gross calorific value; GCV (42.8 MJ kg−1). Its Specific gravity, viscosity, Kinematic viscosity, freezing point and diesel index were also within the limits of diesel
fuel.
The char residues were studied to investigate their characteristics for use as a possible adsorbent. Surface area of char
before and after acid demineralization was determined to determine the adsorptive features for waste water treatment. 相似文献