Radial gas mixing in a fluidized bed using response surface methodology

Radial gas mixing in a fluidized bed was studied using response surface methodology (RSM), which enables effect examinations of parameters with a moderate number of experiments. All experiments were conducted in a 0.29-m ID fluidized-bed cold model. The gas dispersion process within the bed is described using the dispersed plug flow model. Pure carbon dioxide was used as the tracer gas, continuously injected into the center of the bed by a point source. The downstream radial tracer concentration profile was measured using a gas chromatograph.The radial gas dispersion coefficient, D_r, was well correlated with operating parameters and the particle and gas properties: (U−U_mf)/U_mf, H_s/d_b, φ_d, and Ar, with a determination coefficient R² of 0.966. Effect test indicates that the dimensionless characteristic velocity, (U−U_mf)/U_mf, has the most significant influence on D_r, while the static bed height to bed diameter ratio, H_s/d_b, is less remarkable. The interactions of (U−U_mf)/U_mf with the distributor open-area ratio, φ_d, and with the Archimedes number, Ar, both play important roles. An evolutive response surface model was proposed to describe the radial gas mixing in the bubbling/slugging fluidization regimes.     

聚四氟乙烯的加工成型技术

综述聚四氟乙烯（PTFE）的性能特点，以及不同品种PTFE（悬浮聚合PTFE、乳液聚合PTFE和PTFE分散乳液）成型制品所适用的成型工艺。介绍PTFE的模压成型，等压成型，挤压成型，流延成型，热真空成型、热压成型、热吹塑成型及缠绕成型等技术。     

Particle size distribution,mixing behavior,and mechanical properties of carbon black (high‐abrasion furnace)–filled powdered styrene butadiene rubber

High‐abrasion furnace black (HAF, grade N330)–filled powdered styrene butadiene rubber [P(SBR/HAF)] was prepared and the particle size distribution, mixing behavior in a laboratory mixer, and mechanical properties of P(SBR/HAF) were studied. A carbon black–rubber latex coagulation method was developed for preparing carbon black–filled free‐flowing, noncontact staining SBR powders, with particle diameter less than 0.9 mm, under the following conditions: carbon black content > 40 phr, emulsifier/carbon black ratio > 0.02, and coating resin content > 2.5 phr. Over the experimental range, the mixing torque τ_α of P(SBR/HAF) was not as sensitive to carbon black content and mixing temperature as that of HAF‐filled bale SBR (SBR/HAF), whereas the temperature build‐up ΔT showed little dependency on carbon black content. Compared with SBR/HAF, P(SBR/HAF) showed a 20–30% mixing energy reduction with high carbon black content (>30 phr), which confers to powdered SBR good prospects for internal mixing. Carbon black and the rubber matrix formed a macroscopic homogenization in P(SBR/HAF), and the incorporation step is not obvious in the internal mixing processing results in these special mixing behaviors of P(SBR/HAF). A novel mixing model of carbon black–filled powdered rubber, during the mixing process in an internal mixer, was proposed based on the special mixing behaviors. P(SBR/HAF) vulcanizate showed better mechanical properties than those of SBR/HAF, dependent primarily on the absence of free carbon black and a fine dispersion of filler on the rubber matrix attributed to the proper preparation conditions of noncontact staining carbon black–filled powdered SBR. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2494–2508, 2004     

固定化微生物技术在废水处理中的应用

通过对固定化技术方法以及不同载体选择的介绍,分析评价了固定化微生物在废水处理中应用研究进展。认为固定化微生物是一种比一般生物处理法更为高效的方法,并讨论了它在含毒重金属离子废水、有机废水、难降解废水、含磷含氮废水中的应用。研究表明:固定化技术的应用前景十分广泛,但在从实验室阶段走向废水处理的实际应用阶段上还存在一些问题。     

浅谈汽车四轮定位检测与调整技术

四轮定位对汽车的正常行驶起着十分重要的作用。对汽车四轮定位参数进行检测和调整,不仅能确保汽车的正常行驶,还能延长轮胎的使用寿命,同时节省油耗。重点研究了汽车四轮定位的检测方法和调整技术。     

火电厂发电机组常见的电气故障与维修研究

发动机组是火电厂各生产环节中重要的组成部分,其运行效率不但决定了生产效率,还关系着各类生产资源应用的有效性,对实现节能降耗具有重要意义,所以,必须加强对其运行稳定性的管理。分析了火电厂发动机组常见电气故障,并提出了相应的解决措施。     

数控技术在机械制造中的发展应用

随着计算机技术的快速发展,数控加工技术凭借精确和高效的优势,已经成为机械制造中的主流技术。主要分析了数控技术的发展现状和特点,并分析了数控技术在机械制造中的应用优势,以促进机械制造业的快速发展。     

浅谈煤矿地质构造评价指标系统的建立与优选

煤炭资源是我国社会发展的重要能源之一,在煤炭资源开采过程中,必须对煤矿的地质结构进行认真分析。重点分析了煤矿地质结构与煤矿开采的关系,通过对煤矿地质结构的发展规律进行分析,建立了一套完善的煤矿地质构造评价指标系统,从而为煤矿资源的安全开采提供了保障。     

技术创新战略联盟支撑战略性新兴产业发展的机制研究

发展战略性新兴产业已经成为了世界主要国家抢占新一轮经济和科技发展制高点的重大战略。构建和发展产业技术创新战略联盟,是实现技术创新、支撑战略性新兴产业发展的有效途径。阐述了产业技术创新战略联盟的内涵,探讨了其体制机制,分析了它在发展过程中存在的问题,并提出了相关的应对策略。这为构建新型产业技术创新战略联盟,促进战略性新兴产业发展提供了理论基础,进而为政府制订相关政策提供了决策参考。     

试析钻孔灌注桩基础施工技术在桥梁工程中的应用

通过以某桥梁工程为例,探析了钻孔灌注桩基础施工技术在桥梁工程中的具体应用,并为类似桥梁工程的基础施工人员提供了一定的参考和依据。