Solid-handling properties

Moisture content in the gas is known to affect most solids handling properties to the extent that, if powders cannot be kept reasonably well sealed, air-conditioning is necessary if meaningful data are required from powder tests. 

In the pharmaceutical industry, surface area is becoming more important in the characterization of materials during development, formulation, and manufacturing. The surface area of a solid material provides information about the void spaces on the surfaces of individual particles or aggregates of particles [5], This becomes important because factors such as chemical activity, adsorption, dissolution, and bioavailability of the drug may depend on the surface on the solid [3,5]. Handling properties of materials, such as flowability of a powder, can also be related to particle size and surface area [4],... 

The classification system introduced by Carr [29,30] was used to evaluate the flow properties of the sorbitol powders. In Carr s system, a flowable powder is defined as free flowing and will tend to flow steadily and consistently. This is to be contrasted with a floodable powder, which will exhibit an unstable, discontinuous, and gushing type of flow. The parameters in Carr s system include the angle of repose, angle of spatula, compressibility, cohesion, and dispersibility. Based on these parameters, flowability and floodability indices are calculated to determine the handling properties of bulk solids. 

If a flow problem is encountered in solids-handling equipment, at any scale, the most likely reason is that the equipment was not based on the flow properties of the material handled. Often, when flow problems are encountered, the group responsible for selecting handling equipment had little or no knowledge of flow patterns or flow properties. 

Solids with high ionic conductivity have been prepared from KI and Agl e.g. KAg4I5. The rubidium salt was isostructural with this and had somewhat better handling properties, being less sensitive to the effects of moisture, which caused decomposition to Agl and M2AgI3. RbAg4I5 was found to have the highest temperature specific electrolytic conductivity, 0.27 ( 2 cm)-1 of any solid measured. This and other iodide-based solid electrolytes were recently reviewed.379... 

Johanson, J. R. (1981). How to Predict and Use the Properties of Bulk Solids. In Solids Handling. 

In summary, ASPEN has many features, discussed earlier in this paper, which qualify it as a third generation process simulator. A flexible executive system allows the user to have unlimited numbers of dimensions in streams, components, models and stages in equipment models. Solids may be handled in as many phases as desired. Arbitrary properties, called attributes, may be given to these phases and streams to allow handling properties such as particle size distributions. An engineer... 

Particle size. The material handling properties of solid wastes are dependent upon particle size. This appfies as well to feed preparation and air pollution control which are affected by solid-waste particle size and cohesiveness. For wastes such as bulk soils, the amount of fines (from clay and silt) is critical for system design. Cohesiveness, which varies with moisture content, is important for Din and conveyor design. 

Particle size control may also be desirable to facilitate solids handling during formulation. Solids produced by uncontrolled crystallization or precipitation processes can have a broad size distribution that can result in poor flow properties or tendency to segregate. The particle size of APIs can also impact efficiency of blending with excipients, compressibility, flow/ suspension behavior, and compaction performance in downstream equipment. Small particle sizes may be important for controlling dose uniformity in the final formulation, especially for low doses. ... 

The maltodextrin solids are amorphous, white, or off-white powders or granules, which are non-sweet and odorless. The materials are processed by spray drying, fluidized bed agglomeration, and roller compaction to improve their handling properties. Maltodextrins are hygroscopic above 50% RH and need to be stored below... 

At VTT, the following issues are addressed in the present study pyrolysis of solid biomass [3, 4], hot vapour filtration, pyrolysis oil quality [5] and fuel oil specifications [6], storage and handling properties of pyrolysis oil, boiler applications [7], and techno-economic assessment of pyrolysis systems [8]. A considerable amount of work... 

Many solids-handling operations have an effect on the particle size distribution (PSD) of the solid phase. The particle size distribution can also be an important product property. Aspen Plus allows the user to enter a particle size distribution as an attribute of a solid substream. In UniSim Design, the particle size distribution is entered on the PSD Property tab, which appears under worksheet on the stream editor window for any stream that contains a pure or hypothetical solid component. Unit operations such as yield-shift reactor, crusher, screen, cyclone, electrostatic precipitator, and crystallizer can then be set up to modify the particle size distribution, typically by using a conversion function or a particle capture efficiency in each size range. 

In addition, the flowability of a bulk solid is a function of the bulk solids flow properties and the design parameters of the handling equipment. For example, poor flowing bulk solids can be handled reliably in properly designed equipment, and good flowing bulk solids may develop flow problems in improperly designed equipment. As such, a more accurate definition of flowability is the ability of powder to flow in a desired manner in a specific piece of equipment. 

Prior to beginning the discussion of the measurement of flow properties, it is beneficial to review how bulk solids are different than liquids. Since one of our primary concerns with bulk solids handling is flow, a term that is commonly associated with liquids, it is often assumed that the principles of fluid mechanics may be used to describe the behavior of... 

Another point to be made here concerns the effects of gas properties. Generally, the effect of the interstitial and surrounding gas on the mechanics of dry solids handling is neglected. The effects of gas properties may be two-fold ... 

Solids Physical Property Guide, British Materials Handling Board, Ascot, 1983. 

Carr, R.L. 1976. Powder and granule properties and mechanics. In Gas-Solids Handling in the Processing Industries (J.M. Marchello and A. Gomezplata, eds). Marcel Dekker, New York. 

Microencapsulation of flavors is a technology of enclosing flavor compounds (core materials) in a carrier matrix. An amorphous or metastable solid is normally used as a carrier matrix. Microencapsulation is useful for improving the chemical stability of flavor compounds, providing controlled release of flavor compounds from microencapsulated flavor products, providing a free-flowing powder with improved handling properties and physical protection of volatile properties of flavor. 

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