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David Mills - One of the best experts on this subject based on the ideXlab platform.
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Case Study 2: A Coarse Material
Pneumatic Conveying Design Guide, 2016Co-Authors: David MillsAbstract:In this case study a material is selected that has no low-velocity dense phase Conveying capability and so all the scaling is in terms of relatively high-velocity dilute phase suspension flow Conveying. The operating pressure has been limited to 1 bar gauge and so it is applicable to one of the most common pneumatic Conveying systems in industry, being the low-pressure rotary valve as a feeding device and a Roots-type blower for the air supply. Other combinations, of course, are equally applicable, as well as vacuum or higher pressure operation. Once again the scaling is from data obtained for the given material in a test facility and so involves scaling in terms of differences in pipeline bore, Conveying Distance, pipeline orientation, and number of bends. The specification is in terms of the air supply pressure, pipeline bore, and airflow rate required in order to achieve the given duty. The power required for the Conveying system and the solids loading ratio at which the material will be conveyed are evaluated, as well as the specific cost of operating the system.
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Pipeline Scaling Parameters
Pneumatic Conveying Design Guide, 2016Co-Authors: David MillsAbstract:For the reliable design of a pneumatic Conveying system, actual Conveying data for the material to be conveyed is required. If this is not available, it would be recommended that the material should be tested in order to obtain the data. A test facility should be used, or possibly data that has been obtained from another installation, but the actual pipeline configuration does not have to be the same or replicated. Scaling parameters are presented in this chapter that will allow such data from one pipeline to be scaled to that of the required facility. Differences in pipeline bore, Conveying Distance, number and geometry of bends, and pipeline orientation can all be taken into account. For a given plant pipeline, a number of different combinations of pipeline bore and air supply pressures will generally be capable of meeting the required duty. Such an analysis is included and it is shown how the choice of Conveying parameters can influence both the cost of operating the plant, in terms of power requirements, and the potential capital cost of the plant.
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Chapter 17 – Design Procedures
Pneumatic Conveying Design Guide, 2016Co-Authors: David MillsAbstract:Logic diagrams are presented for the design of pneumatic Conveying systems based on the use of both mathematical models and Conveying data. Logic diagrams are also presented for checking the performance of an existing system, or for a potential change of duty, again based on the use of both models and data. There is rarely a single solution to the specification of a pneumatic Conveying system for a given duty. As a consequence the logic diagrams include numerous checks so that optimum solutions are achieved in terms of either obtaining the minimum power requirement for a given duty, or achieving a maximum material flow rate for the given Conveying parameters. To help in this process several series of design curves are included to illustrate the potential influence of the major system variables such as Conveying Distance, pipeline bore, and air supply pressure, as well as the problematical issue of material type.
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First approximation design methods
Pneumatic Conveying Design Guide, 2016Co-Authors: David MillsAbstract:For feasibility studies an approximate solution to a problem will often suffice in the first instance so that a reasonable order of magnitude of the variables involved can be obtained, particularly if a comparison is to be made with alternative mechanical means of Conveying a material. This will give sufficient details of the pneumatic Conveying system in terms of pipeline bores, air supply pressures, and airflow rates for a given duty, in terms of material flow rate and Conveying Distance required, so that capital cost estimates for plant items such as pipelines, compressors, feeding devices, and filtration plant can be made. Operating costs for the plant are also likely to be required and so with data on airflow rate and air supply pressure required, this is a straightforward procedure. As was shown in previous chapters, a given duty can generally be achieved with a range of air supply pressure and pipeline bore combinations, and so this method of analysis will enable the best combination of Conveying parameters to be achieved for the given duty.
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Multiple Use Systems
Pneumatic Conveying Design Guide, 2016Co-Authors: David MillsAbstract:All pneumatic Conveying systems are not dedicated to the Conveying of a single material over just one Distance. In many cases, several materials have to be conveyed to a number of different reception points. In a manufacturing process, a single pipeline is used to convey a diverse range of materials from a number of supply hoppers to a single delivery point for blending. In many industries, such as glass and food, a wide variety of materials have to be conveyed by a common system, since there is a requirement to deliver a given menu for a particular process. In ship off-loading, a single line may be used to unload several different materials and to convey them to separate locations. In all of these cases, it is essential that each material should be conveyed successfully. However, each material may have different Conveying characteristics and as a consequence, the air requirements for the Conveying of different materials and the material flow rates achieved can vary significantly. Conveying Distance can also have a significant influence on Conveying performance. Some of the materials to be transported may be capable of being conveyed in dense phase, and hence at low velocity, while others may have no dense phase capability and will have to be conveyed in dilute phase with a high Conveying air velocity. The Conveying performance of different grades of the same material can also widely differ.
K C Williams - One of the best experts on this subject based on the ideXlab platform.
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modeling and analysis for fluidized dense phase Conveying including particle size distribution
Powder Technology, 2013Co-Authors: Niranjana Behera, Vijay K Agarwal, Mark Jones, K C WilliamsAbstract:Abstract Pressure drop in fluidized dense phase pneumatic Conveying involves frictional interactions among gas, particle and pipe wall. There have been numerous correlations proposed by different researchers for predicting the pressure drop in fluidized dense phase Conveying. In this paper steady state flow equations have been written for different phases and these equations are solved by assuming certain factors for different Conveying materials. For writing the flow equations, a single gas phase and certain number of solids phases (which are chosen based on the particle size distribution of the Conveying material) have been considered. Experimental data have been used as initial conditions at the exit of the pipeline in order to solve for the value of the flow parameters at the inlet of the pipeline. Experimental data have also been used to find the maximum possible Conveying Distance or maximum possible Conveying pipeline diameter by imposing certain limiting conditions of Conveying. Scaling equations for the solids mass flow rate and the air mass flow rate have been used to predict the pressure drop for different pipeline diameters and pipeline lengths.
Yide Geng - One of the best experts on this subject based on the ideXlab platform.
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Transportation characteristics of gas-solid two-phase flow in a long-Distance pipeline
Particuology, 2015Co-Authors: Xiaoqiang Zhang, Dongfeng Zhang, An Wang, Yide GengAbstract:Abstract In this study, experiments on fly ash Conveying were carried out with a home-made long-Distance positive-pressure pneumatic Conveying system equipped with a high performance electrical capacitance tomography system to observe the transient characteristics of gas–solid two-phase flow. The experimental results indicated that solids throughput increased with increasing solids–gas ratio when the Conveying pipeline was not plugged. Moreover, the optimum operating state was determined for the 1000 m long Conveying pipeline with a throttle plate of 26 orifices. At this state the solids throughput was about 12.97 t/h. Additionally, the transportation pattern of fly ash gradually changed from sparse–dense flow to partial and plug flows with increasing Conveying Distance because of the Conveying pressure loss. These experimental results provide important reference data for the development of pneumatic Conveying technology.
Peter W Wypych - One of the best experts on this subject based on the ideXlab platform.
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an investigation into pressure fluctuations for fluidized dense phase pneumatic transport of fine powders
Powder Technology, 2015Co-Authors: Anu Mittal, Soumya Suddha Mallick, Peter W WypychAbstract:Abstract This paper presents results of an ongoing investigation into the flow mechanism for the pneumatic Conveying of fine powders conveyed from fluidized dense phase mode to dilute-phase. Three different techniques of signal analysis (i.e. rescaled range analysis, phase space method and technique of Shannon entropy) have been applied to the pressure fluctuations obtained during the solids–gas flow of fly ash (median particle diameter 30 μm; particle density 2300 kg m − 3 ; loose-poured bulk density 700 kg m − 3 ) through a 69 mm I.D. × 168 m long pipeline and also white powder (median particle diameter 55 μm; particle density 1600 kg m − 3 ; loose-poured bulk density 620 kg m − 3 ) through a 69 mm I.D. × 148 m long test rig. Results show that with increasing Conveying Distance (and Conveying velocity in the direction of flow), there is an overall decrease in the values of Hurst exponent, an increase in the area covered by the phase-space diagram and an increase in the Shannon entropy values, indicating an increase in the degree of complexity of flow mechanism (or turbulence) along the length of the Conveying pipeline. All the three methods have revealed that the closely coupled bends reverse the trend of change of Hurst exponent, phase-space diagram area and Shannon entropy values. This is due to the slowing down of particles caused by the friction of particles along the bend wall resulting in dampened particle turbulence.
Niranjana Behera - One of the best experts on this subject based on the ideXlab platform.
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modeling and analysis for fluidized dense phase Conveying including particle size distribution
Powder Technology, 2013Co-Authors: Niranjana Behera, Vijay K Agarwal, Mark Jones, K C WilliamsAbstract:Abstract Pressure drop in fluidized dense phase pneumatic Conveying involves frictional interactions among gas, particle and pipe wall. There have been numerous correlations proposed by different researchers for predicting the pressure drop in fluidized dense phase Conveying. In this paper steady state flow equations have been written for different phases and these equations are solved by assuming certain factors for different Conveying materials. For writing the flow equations, a single gas phase and certain number of solids phases (which are chosen based on the particle size distribution of the Conveying material) have been considered. Experimental data have been used as initial conditions at the exit of the pipeline in order to solve for the value of the flow parameters at the inlet of the pipeline. Experimental data have also been used to find the maximum possible Conveying Distance or maximum possible Conveying pipeline diameter by imposing certain limiting conditions of Conveying. Scaling equations for the solids mass flow rate and the air mass flow rate have been used to predict the pressure drop for different pipeline diameters and pipeline lengths.