SAR - Review
Executive Preface
An introduction to the content and overall objectives of the IFPRI research programme of work was presented in Stage I report where the available results were evaluated with the aim of writing a Design Guide. Recapitulating briefly, the IFPRI work was instigated in order to:
- Develop new, physically based correlations which describe rigorously the flow behaviour of non-colloidal settling slurries and which may be used to predict accurately the head loss in straight pipes and essential, standard pipe fittings.
2. Validate the use of existing, well accepted correlations describing the flow behaviour of colloidal slurries for industrial scale-up design calculations, obtain representative head loss data for standard pipe fittings and finally, establish the optimum rheological slurry properties required to minimise the power consumption with hydraulic transportation.
This report entitled “IFPRI Design Guide, (Stage II)” is a first step towards producing a concise document based on the findings of the IFPRI programme of work. The penultimate objective is to resolve the uncertainties associated with known design procedures and hence to provide a comprehensive and reliable source of reference for the design of hydraulic conveying systems needed in industrial applications.
Abstract
The need for and the principles of morphological analysis as applied to particulate matter are briefly discussed. Applications of morphological analysis to a number of problems are cited. Topics include:
- relating morphology to the mechanisms of powder production;
- wear debris analysis by morphological analysis;
- kinetic modeling of crystallization processes.
Relationships between the behavior of particulate materials and the morphology of the particles are discussed in connection with:
- abrasive wear of metals;
- sedimentation in low flow regimes;
- measuring of bulk properties including internal angle of friction and flow times;
- dry separation technology;
- scrap recovery techniques.
The adaptation of the particle image analyzing system to analyze color as a morphic feature is presented. A number of examples of mixture analysis - classification studies are detailed and finally future work in packed and fluidized beds and slurry transportation is outlined.
This document is a draft of the final report of the first stage of an IFPRI project, "Particle Characterisation". The document is intended to summarise the state of the subject, Particle Characterisation, for the benefit of the member companies of IFPRI. In particular, it is intended to form the basis for discussions at the annual meeting of IFPRI in June, 1980 and for recommendations on any further stages of this project. The document may well serve to act as a guide in the consideration of new proposals which may arise in the relatively near future on this topic.
The approach which has been adopted is to conduct a literature search covering a time span of five years. It may reasonably be assumed that anything which occurred previously is either developed and discussed within this period, is well known or was not worthy of note. That bibliography is listed as Part 5 of this report. The bibliography has been classified into sections which either appeared as identifiable and significant sections or, alternatively, correspond to a topic which was identified by member companies as having specific interest. In some of these sections the literature is sparse. The literature on which the specialised reports which were the subject of sub-contract is included separately with those reports at this stage although that can be compounded into the bibliography list in the final report. The survey has included some Japanese literature but the work in that country is presumably subject to much more intensive survey in the report which is submitted by Professor Inoya.
The member companies of IFPRI identified eleven topics as being of special interest to them at the time of the survey in 1979. Four of those topics were particularly specialised and were made the subject of a separate sub-contract for review by an appropriate university department. Those reports which have been received by 10th May are included as section 6. The reports which were not received at that time will either be tabled at the June meeting or will be included in the final report of the first stage of the project. The other seven topics were mainly concerned with particle size measurement, with the measurement of process variables such as velocity and concentration and with the measurement of particle density. Section 3 constitutes a review of the significance of the literature search on those topics highlighting significant papers and commenting upon the state of knowledge of the subject and the current activity in research and apparent application. The topic of pore size measurement has, for this purpose, been ignored and included with the sub-contract on surface area measurement.
In order to put these various reviews into context, an overall appraisal of the subject of particle characterisation has been written, discussing basically the philosophy of the subject and attempting to create an overview through which the other topics might be related. This is presented in Section 2.
Included in the IFPRI Proposal on Particle Characterisation were two other items. Firstly, a view on the current problems in particle characterisation and secondly a proposal as to how IFPRI might proceed in this topic. This survey has obviously not substantially changed the opinions of the authors in these two matters but it is, perhaps, necessary to reiterate and expand them for the purposes of discussion at the annual meeting. Section 4 expresses a view on the current problems in particle characterisation and the areas which are timely for development. It is a reiteration of the opinions in Section 3 of the original proposal. Section 4 is also a recommendation of the course of action which could be followed by IFPRI and is a reiteration of Section 5 of the original proposal.
The Phase I Preliminary and Annual reports include the State of the Art Review for the following four research fields in Japan:
- A. Slurry Handling and Rheology
- B. Flow and Cohesion of Powders
- C. Agglomeration in Particulate Systems
- D. Deliquoring of Filter Cakes
This Phase II Preliminary Report includes a State of the Art Review for the following two additional research fields in Japan:
- E. Particle Characterisation
- F. Solid-Solid Separation
The previous Phase I reports were mainly compiled by use of the suggestions and advice of 5 consultant professors, who are specialists in each field. The critical opinion of the Phase I Annual Report is based on a general review and my own personal views.
However, this Phase II report has been written based on the results of questionaires mailed to individual principal research personnel. Therefore, it may contain better information than the Phase I reports, but the results might be exaggerated. Each research field was studied in several of the same laboratories as the ones in other fields. That is, some laboratories are listed in more than one field, because the same subjects have been studied by two or three researchers, or the subjects have some correlation with other fields. Especially, the fifth field "E Particle Characterisation" has many connections with other fields, because it is a fundamental scientific subject in particle technology.
The highly selective state of the art review has been assigned for the following four R and D project areas which are shown in Appendix III in detail.
A. Slurry Handling and Rheology
B. Flow and Cohesion of Powders
C. Agglomeration in Particulate Systems
D. Dsliquoring of Filter Cakes
I have selected five active professors in the above areas as consultants, and discussed with them the general outline of the projects. I have prepared the survey guideline and the questionnaire format in Japanese.
The five consultant professors have written the survey reports by use of the questionnaires. On the other hand, a post graduate student has listed up Japanese literatures recently published in the above four areas. I have also passed or sent the questionnaires to selected scholars and have visited several university laboratories and three government research institutes in Japan last March. Direct interviews with key personnels and making laboratory tours by travelling around were the best way to get adequate informations. It is difficult to say which laboratories are most highly trained and well equipped in Japan. However, I have listed their research activities each on a'separate page, which we think to be important ones, as follows.
The term agglomerate is generally described as an assembly formed by various binding mechanism 1)2)3) existing between solid particles. A number of problems relating to agglomerate strength are divided into two groups. One is the breakage of spherical or irregular shaped agglomerates induced in particle handling processes such as solid-liquid mixing, moving bed, fluidized bed, rotary drum, hopper, and so on. Another is the evaluation of a strength of agglomerates or compacts handled in the field of various granulation techniques. In view of each agglomerate having various shapes, dimensions, and particular structure, it is extremely difficult to indiscriminately discuss the mechanical properties related to agglomerate strength. However, it is well known that typical tensile strength of agglomerate, in general, is influenced by particle diameter and porosity as shown in Fig. 1, and also the pioneered studies on other important factors influenced by forces existing between particles have been made by Rumpf and his coworkers 4)5). Other agglomerate strength, generally, of abrasion/attrition and impaction are important factors 6)7) to judge whether or not their shapes are maintained during handling and processing in various industries.