Prediction of Optimal Operating Conditions for Dense-Phase Pneumatic Conveying Systems

Publication Reference: 
43-03
Author Last Name: 
Wypych
Authors: 
Professor Peter W Wypych, Mr David B Hastie, Dr Jianglin Yi
Report Type: 
ARR
Research Area: 
Powder Flow
Publication Year: 
2001
Publication Month: 
12
Country: 
Australia

The fluidised dense-phase (FDP) conveying of powders and low-velocity slug-flow (LVSF) of granular bulk solids are the most common and popular modes of dense-phase used in industry. However, the accurate prediction of conveying performance still is not possible from first principles and relies heavily on empiricism.

The main aim of this project is to develop the necessary understanding, databases, guidelines and models for the purpose of predicting accurate optimal operating conditions for the two modes of dense-phase. However, as was mentioned in the original research grant application, it was unlikely that both the FDP and LVSF sections could be completed thoroughly in a single 3-year period (ie due to the amount of work involved). Hence, top priority was given initially to the LVSF section of the project, although some progress was made also with the FDP section of work. However, with the 3-year extension to the research grant, a substantial amount of work now can be completed in the FDP section, as well as completing particular outstanding issues in the LVSF section.

Several difficulties were encountered during the course of the first 3 years of the project (eg unexpected results and phenomena) and delayed progress in certain areas. In some cases, it was not possible to complete particular scheduled tasks (eg testing aluminium and mild steel pipes with a wide range of granular solids). In other cases, it was necessary to pursue new research issues (eg rotary valve air leakage, new pipe friction and stress transmission testers). However, in terms of achieving the main goals, there is no doubt that the project has been successful in terms of improved understanding and the development of new databases and models for the prediction of LVSF performance. For example, the new transport boundary and pressure drop models have been found quite accurate for the poly pellet type materials tested to date and also have been able to explain some of the interesting and unexpected phenomena encountered during the experimental stages of the project.

Unfortunately, due to the various problems and delays to date, as well as the new discoveries and developments, the numerous pipe wall materials and bulk solids planned originally for the LVSF section were not able not been tested, preventing further confirmation of model accuracy and validity. Additional work is planned over the next 12 months for this purpose (eg testing at least one other granular material with properties different to the poly pellets).

A significant amount of additional time will be needed for the expected relatively more complex FDP section of work. For example, only one product and a few different pipelines were able to be tested by the end of the initial 3-year period. The 3-year extension will allow this to be pursued in greater detail (eg with other powders and pipeline configurations), as well as the commencement of investigations into modelling techniques.

This Annual Report summarises the research progress and major achievements to date, as well the forward plan for the next 12 months.