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31.
Yao CHEN Jinhui LI Huabo DUAN Zhishi WANG 《Frontiers of Environmental Science & Engineering》2011,5(2):167-174
Mechanical waste-processing methods, which combine crushing and separation processes for the recovery of valuable materials, have been widely applied in waste printed wiring board (PWB) treatment. However, both the high impact toughness and the tensile and flexural strengths of whole PWB with a laminated structure result in great energy consumption and severe abrasion of the cutters during multi-level crushing. In addition, the high temperatures occurring in continual crushing probably cause the decomposition of the polymer matrix. A thermal-crack method using residual steam as the heating medium has been developed to pre-treat waste PWBs. This treatment reduces the mechanical strength in order to improve the recovery rate of valuable materials in subsequent mechanical recycling. The changes of the PWBs’ macro-mechanical properties were studied to evaluate thermal expansion impacts associated with changes in temperature, and the dynamic dislocation micro-structures were observed to identify the fracture mechanism. The results showed that thermal cracking with steam at the temperature of 500 K can effectively attenuate the mechanical properties of waste PWBs, by reducing the impact, tensile and flexural strengths respectively, by 59.2%, 49.3% and 51.4%, compared to untreated PWB. Thermal expansion can also facilitate the separation of copper from glass fiber by reducing peel resistance by 95.4% at 500 K. It was revealed that the flexural fracture was a transverse cracking caused by concentrated stress when the heating temperature was less than 500 K, and shifted to a vertical cracking after exceeding 500 K. 相似文献
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René Rossi Eric Indelicato Walter Bolli 《International journal of occupational safety and ergonomics》2013,19(3):239-245
The aim of this study was to analyse the transfer of steam through different types of textile layers as a function of sample parameters such as thickness and permeability. In order to simulate the human body, a cylinder releasing defined amounts of moisture was also used. The influence of sweating on heat and mass transfer was assessed.The results show that in general impermeable materials offer better protection against hot steam than semi-permeable ones. The transfer of steam depended on the water vapour permeability of the samples, but also on their thermal insulation and their thickness. Increasing the thickness of the samples with a spacer gave a larger increase in protection with the impermeable samples compared to semi-permeable materials. Measurements with pre-wetted samples showed a reduction in steam protection in any case. On the other hand, the measurements with a sweating cylinder showed a beneficial effect of sweating. 相似文献
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啤酒厂麦汁煮沸耗热占全厂生产用热的50%,实现煮沸二次蒸汽的再利用是企业能否获得较高经济回报的重要环节。从技术原理、技术优势、经济成本等角度对储能与真空蒸发联合热能回收系统进行了分析和阐述,以期为啤酒企业在借鉴和引进节能新技术中起到促进作用。 相似文献
37.
汽爆麦草固态发酵木质素酶 总被引:1,自引:0,他引:1
木质素是地球上主要的可再生芳香族化合物 ,是地球上仅次于纤维素的第二丰富可再生天然资源 ,然而 ,对它的利用研究却很少 ,是天然高分子中未开发的领城[1] .80年代初发现了木质素过氧化物酶 (LiP) [2 ,3] 和锰过氧化物酶 (MnP) [4 ] 以后 ,木质素酶和木质素生物降解研究取得了一定进展 .但木质素微生物转化降解研究中仍存在许多问题 .( 1)由于木质素酶解是一种非专一性的、以自由基为基础的链反应过程[5] .因此 ,木质素酶在化学工业、煤化学和环境保护方面具有很大的开发前景 .而现在木质素酶的生产大多用合成培养基 ,必需添加昂贵的… 相似文献
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The effects of reactant composition and steam on propane combustion over Pd/LaFe0.8Co0.2O3 catalyst were investigated.Propane conversion and the oxidation state of palladium were strongly affected by the redox ration of reactants.Higher propane conversion could be obtained under rich conditions and explained as a complex balance between oxidation and steam reforming.Water produced in the oxidation could promote the propane conversion by steam reforming.However,the presence of excess steam would bring about inhibition. 相似文献
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中小型锅炉烟气汽流喷雾干燥法脱硫的研究 总被引:3,自引:0,他引:3
以4t 链 条炉为 对象,研究 了中小 型燃煤锅 炉的 汽流 喷雾 干燥 法脱 硫,着 重 研究 了汽 流 式雾化器、气体分布 器、脱硫 塔及其配 套设备, 确定了最 佳操作 条件。结 果表明:气 液比 为20 ~30 ,蒸汽压力为 06 ~07 M Pa ,吸 收剂 计量 比为 11 ~16 ,烟 气中 S O2 去 除率 可达 76 % ~97 % ,不 发生粘壁、粒子结块 现象 相似文献
40.
本文分析研究了油田注汽系统盐析现象及其成因和危害,并根据盐析成因探索了预防注汽盐析方法以减少甚至消除其危害。通过研究确定,采用高压旋流饱和蒸发与低压闪蒸和多效蒸集成技术是预防注汽系统盐析并减少甚至消除盐析及其造成的危害较为有效的方法。 相似文献