炭黑在气力输送系统中的破碎原因的分析

分析了炭黑在气力输送过程中的破碎机理．通过实验．介绍了气力输送系统中炭黑的种类和炭黑的物性对炭黑的破碎的影响．指出气力输送系统的输送管路长度和布置以及输送参数如输送压力和输送速度等的变化直接影响着炭黑的破碎率的大小．为更好地解决炭黑在气力输送中存在的问题,优化炭黑气力输送系统的设计提供了依据．     

橡胶厂炭黑气力输送系统设计

结合橡胶厂炭黑气力输送系统的使用情况,对输送管道、空气流量控制元件、供料装置、分离过滤设备等主要部件进行优选;对安全阀、减压阀、空气过滤器和Laval管喉径选择进行计算;对输送安全性控制要求和特殊品种炭黑如牌号为N772、N774的炭黑输送管道的选择进行阐述。结果表明,通过对气力输送系统主要设备的优选,可有效减小能耗,减少输送过程中出现的炭黑粒子破坏严重以及管道残余、阻塞、泄漏问题,确保输送系统可靠、平稳运行。     

气力输送闭式管路系统特性分析

提出了气力输送闭式管路系统这一新的思路，给出了气力输送闭式管路系统除法特性的计算方法，分析结果表明，气力输送闭式管路系统较 开式管线系统具有能循环利用气流功能、不需高效除尘器、总排尘量大幅度减少等优点。     

射流管在气力输送中的应用

对物料气力输送的各种供料方式的性能、特点和使用场合进行了比较 ,重点讨论了传统文丘里供料器实际应用中存在的问题 ,介绍了几种国内外新型的文丘里供料器结构及其特点和用途。指出采用组合式供料器 ,即将文丘里供料器与机械旋转式连续供料器进行组合使用 ,可以同时改善它们两者单独使用时存在的问题。文中介绍了LAVAL管密相输送气量控制方面的应用 ,指出LAVAL管在气力输送中主要起稳定空气流量和压力的作用 ,使输送过程稳定、均匀 ,并简要介绍了气力输送系统的设计方法和步骤     

石灰长距离气力输送系统的试验研究

基于气力输送理论,通过石灰的长距离输送试验系统的建立,研究输送过程中耗气量、管道压力损失、物料输送前后的状态等重要输送特性。结果表明,将气力输送应用在长距离的石灰输送上是完全可行的,可解决钢铁行业的高粉尘污染问题,极大地改善工作环境。     

气力输送系统的特性及周期成本的分析

概述了气力除灰系统的特点和分类,较详细的介绍了气力输送系统的周期成本的计算方法,并用一个工程实例加以比较说明.     

气力输送系统中弯管耐磨性的研究

在气力输送系统在多个领域得到广泛应用的同时,系统弯管磨损问题也引起了人们的关注。基于这种情况,本文对气力输送系统中弯管的磨损机理进行了分析,然后对系统弯管耐磨性的影响因素和增强方法展开了研究,以期为关注这一话题的人们提供参考。     

等离子体技术在炭黑制备中的应用

等离子体法制备炭黑的基本原理是碳氢化合物在高温等离子体中的热解。通过对比等离子体炭黑和传统炭黑的基本性能及生产工艺,表明等离子体炭黑具有如下优点:产率高,碳转化率接近100%;初级粒子粒径小,比表面积大,满足对特种炭黑的要求;清洁生产,副产品为氢气,无CO2、NOX等污染物产生;原料适应性广。通过介绍等离子体法制备炭黑的研究历史、发展现状及工业应用前景,结合我国炭黑产业中存在的基础理论研究薄弱、缺乏具有自主产权的高性能炭黑制备技术研发的现状,论证了开发等离子体炭黑制备技术的必要性。指出做好基础数据的采取工作,开发新的等离子体技术和炭黑制备工艺相结合的工艺是今后研究工作的方向。     

论正压浓相气力输送技术在CFB中的应用

CFB的除灰方式及除灰系统对全厂的安全经济运行及环境保护有着重大的影响,正压浓相气力输送系统具有明显的节约能源减少维修费用改善环境和利于综合利用等优点。     

导电炭黑及在橡胶中的应用

用于橡胶基质的导电填充剂主要是炭黑,此外还有碳纤维、金属粉、金属箔、不锈钢细丝等。本文主要对导电炭黑的种类特点以及在橡胶中的应用进行阐述。     

Investigating Straight-Pipe Pneumatic Conveying Characteristics for Fluidized Dense-Phase Pneumatic Conveying

This article presents results from an investigation into the pneumatic conveying characteristics (PCC) for horizontal straight-pipe sections for fluidized dense-phase pneumatic conveying of powders. Two fine powders (median particle diameter: 30 and 55 µm; particle density: 2300 and 1600 kg m^?3; loose-poured bulk density: 700 and 620 kg m^?3) were conveyed through 69 mm I.D. × 168 m, 69 mm I.D. × 148 m, 105 mm I.D. × 168 m and 69 mm I.D. × 554 m pipelines for a wide range of air and solids flow rates. Straight-pipe pneumatic conveying characteristics obtained from two sets of pressure tappings installed at two different locations in each pipeline have shown that the trends and relatively magnitudes of the pressure drops can be significantly different depending on product, pipeline diameter and length and location of tapping point in the pipeline (indicating a possible change in transport mechanism along the flow direction). The corresponding models for solids friction factor were also found to be different. There was no distinct pressure minimum curve (PMC) in any of the straight-pipe PCC, indicating a gradual change in flow transition (change in flow mechanism from dense to dilute phase). For total pipeline conveying characteristics, the shapes of the PCC curves and the location of the PMC were found to be significantly influenced by pipeline layout (e.g., location and number of bends) and not entirely by the dense-to-dilute-phase transition of flow mechanism. Seven existing models and a new empirically developed model for PMC for straight pipes have been evaluated against experimental data.     

粉体性能对浓相气力输送特性的影响

气力输送过程中物料性能是确定输送特性的重要因素,因此,粉料气力输送技术的实现要以对粉料的性能研究为基础。文中对影响气力输送的粉体基本性能及其相关参数做了较全面分析,其中粒子尺寸、粒径分布、形状是影响粉料是否可适用于浓相气力输送的关键参数,其它特性都与这3种特性相关联。介绍了几种应用广泛的粉料气力输送特性分组方法,并进行了简要评述,同时指出了今后的研究方向。     

Effect of Dune Formation on Pressure Drop in Horizontal Pneumatic Conveying System

Pneumatic conveying is widely used in industries handling large amount of granular materials to transport the solid particles; however, the process is energy intensive as an instability of flow sets in the transportation line even in the dilute regime, causing large fluctuations in the line pressure drop, the reason of which is not clearly understood. Here, we investigate, both by experiments and by using numerical simulations, the instability transition regimes and identify the reasons of the fluctuations observed in the line pressure drop in a horizontal pneumatic transport system operating at near-saltation conditions. It is observed that the increase in the pressure drop (immediately after the saltation) is accompanied by the formation of distinct dunes. It is also observed that the line pressure drop depends on the axial location of the dune and shows large fluctuations in the regime where the dunes are unstable. Results obtained from the numerical simulations suggest that the increase in the line pressure drop in the presence of dunes is essentially due to the shear stresses at the dune surface which are larger than that for the flows in clean pipe.     

密相气力输送系统中几种气量控制方式的比较

从调压范围、压力特性和流量特性方面介绍了减压阀的主要性能,讨论了气力输送交流中减压阀的选择和调节,分析了密相气力输送系统中各种气量控制方法,对其各自的优缺点进行了详细讨论,重点分析减压阀及减压阀与拉法尔联合气量控制系统的优、缺点,表明可调式拉法尔管是今后气力输送气量控制发展的方向。     

不规则宽粒径石灰石粉脱硫及气力输送技术

通过分析干法脱硫技术及其影响因素,如石灰石性能和石灰石颗粒直径等,提出脱硫剂的选择及气力输送的方式,同时分析了气力输送中的问题,如透气性差和保气性差引起的不易流化等,并相应提出解决办法和输送设计方案。针对不规则宽粒径石灰石粉粒具有的特殊颗粒学特性和复杂气固两相流场,提出了解决方案,为更好地设计石灰石粉气力输送系统提供参考。     

Particle Trajectories in Dilute Phase Pneumatic Conveying

A nonintrusive cross-correlation method to measure the particle velocities in dilute phase pneumatic conveying is described. The cross-correlation function generated gives information about the time it takes for a particle to travel between two optimally placed measurement planes. Experiments and CFD simulations are used to estimate an optimal inter-plane distance for various flow conditions.     

A Possible Scaling-up Technique for Dense Phase Pneumatic Conveying

In this article experimental findings have been presented to show that the pressure drop coefficient (K) for vertical and horizontal pneumatic conveying for a given bulk material follows a certain pattern. The pressure drop coefficient for vertical pneumatic conveying for a given material has been found to be independent of any variation of particle size distribution, within experimental limits. The pressure drop prediction technique proposed by the authors previously has been validated with the test results of alumina and bentonite.     

Modeling Dense-Phase Pneumatic Conveying of Powders Using Suspension Density

This article presents results of an investigation into the modeling of pressure drop in horizontal straight pipe section for fluidized dense-phase pneumatic conveying of powders. Suspension density and superficial air velocity have been used to model pressure drop for two-phase solids-gas flow. Two applicable models formats (developed by other researchers using two different definitions of suspension density) were used to represent the pressure drop due to solids-gas flow through straight pipe sections. Models were generated based on the test data of conveying power-station fly ash and electrostatic precipitator (ESP) dust (median particle diameter: 30 and 7 µm; particle density: 2300 and 3637 kg m^?3; loose-poured bulk density: 700 and 610 kg m^?3, respectively) through a relatively short length of a smaller diameter pipeline. The developed models were evaluated for their scale-up accuracy and stability by using them to predict the total pipeline pressure drop (with appropriate bend model) for 69 mm I.D. × 168 m; 105 mm I.D. × 168 m and 69 mm I.D. × 554 m pipes and comparing the predicted versus with experimental data. Results show that both the models with suspension density and air velocity generally provide relatively better prediction compared to the conventional use of solids loading ratio and Froude number. For fly ash, the two formats result in considerable different predictions, whereas they provide relatively similar results for ESP dust.