In the scope of blow-tank (batch), pneumatic conveying systems, it is common practice to rate solids flowrate based on a time-averaged value of batch size and cycle time. But depending on the system design and operation, the realtime or transient flowrate can vary significantly from these averaged values. These differences can lead the unwary to make poor choices in system design or blowtank operation, which will result in either pipeline blockages (if gas flowrate is inadequate) or excessive pipeline wear (if the gas velocity is too high). Several alternatives are considered to be good engineering practice for the design or optimization of a pneumatic conveying system. One makes use of specific conveying characteristics of the transported material, which relate gas flowrate, solids flowrate and line pressure drop in the form of a performance map. Another method uses load-cell data, usually from the receiving hopper. The solids flowrate is calculated from the derivative of the mass collected with respect to time. Pressure measurements are commonly recorded. As described in this article, the approximate realtime solids flowrate of a single blow-tank, pneumatic-conveying system can be conveniently determined from batch-size and line-pressure history (for a positive-pressure system). The method of determining approximate solids flowrates described in this paper is based on the assumption that the pressure drop in the conveying line at any instant is related to the mass flowrate of solids, and that this relationship is constant for all flowrates.
Using pressure to determine realtime solids flowrates
Anwendung von Druck zur Bestimmung des Strömungsverhältnisses von Festkörpern im Echtzeitbetrieb
Chemical Engineering, New York ; 109 , 12 ; 43-46
2002
4 Seiten, 4 Bilder, 1 Tabelle, 3 Quellen
Article (Journal)
English
Material flowrates in pneumatic conveying
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