Zur Verfestigung von Schüttgütern – Mikroprozesse und Kinetikmodelle

Storage tanks are important elements of a self-operating closed processing system. The reliability and availability of storage equipment essentially depends on the flow behaviour of particulate solids in storage containers. A wide residence time distribution (i.e. too long a storage time at rest) in silos, bunkers or transportation containers, respectively, can lead to the hazardous problem of so-called “time consolidation” of particulate solids. During this hardening process, solid bridges are forming with resulting solidification and solid properties of bulk material. In principle, there are four main physico-chemical effects in bulk materials storing and handling which can produce solid briding between the particle contacts due to crystallisation, chemical reactions, solidification of high-viscous bonding agents and sintering. Generally, new adhesion force based models are presented to describe the consolidation kinetics of particulate solids. Preliminary solutions of kinetic model equations are discussed and compared with new test results and practical conclusions are drawn concerning the reliable processing, storage and transportation of bulk materials.     

Homogenisieren von Schüttgütern in Mischsilos

Homogenization of bulk solids in blending silos . Blending silos are used for blending and homogenization of large quantities of bulk solids. Depending on how the energy is introduced, we distinguish between pneumatic, mechanical, and gravity flow blenders. The different blending principles are described and the suitability of the blending systems for certain types of bulk solids is explained. Fluidized bed blenders are suitable for homogenization of free flowing fine powders. Gravity flow blenders are used for blending of granular bulk solids. Homogenization of cohesive powders is accomplished in mechanical blending silos. It is necessary for selection of a suitable homogenization system to know the fluidization behaviour and the flow properties of the respective bulk solids. These properties can be determined in laboratory tests.     

Lagern und Umschlagen von Schüttgütern in der Chemischen Industrie

Storage and trans-shipment of bulk solids in the chemical industry. Theoretical fundamentals of the motion of bulk solids in bunkers were considered in detail at the Annual Meeting of Chemical Engineers held at Karlsruhe in 1975 [1]. The present account will deal exclusively with practical aspects playing a role in the building and operation of storage and trans-shipment facilities for bulk solids. Various problems encountered are illustrated for some typical bin storage units in the chemical industry. Moreover criteria are mentioned which can assist the design engineer in the correct choice of silo type and suitable materials of construction, and the ascertainment of the right size of silo. Filling and emptying devices are also proposed for differing spatial circumstances and various tasks. Important ancillary equipment such as ladders, platforms, and devices for monitoring filling levels are also treated. A consideration of the principal regulations governing the operation of silo systems is followed by some hints on the transport, erection, and assembly of silos.     

Zur Fließfähigkeit von Schüttgütern – Definition und Meßverfahren

Flowability of Bulk Solids – Definition and Measuring Principles . The flowability of bulk solids has to be known for many practical applications. The present paper describes how the flowability is defined and on which physical properties it depends. Experimental determination of the flowability using a shear test is demonstrated. Conditions influencing measuremed results are described. Finally an overview of various methods used for characterization of the flowability of bulk solids is given.     

Der Sicherheitsaspekt beim Eintrag von Schüttgütern in Behälter

Safety aspects of charging bulk material into vessels or containers . The safe charging of bulk material requires a careful analysis of the potential sources of danger which can result from the physical properties of the materials and the design and construction material of plant and equipment. The method adopted in this analysis is illustrated and explained for selected examples. Criteria for safe charging methods are compiled and explained. A selection of proven charging equipment is listed and technically evaluated with respect to safety and operating criteria. Steps that must be taken to avoid charging errors are discussed. Special problems encountered on connecting pressureless charging devices to pressure vessels are outlined explained. The utilization of inert gas as a preferred method of explosion protection is discussed. Various methods are compared, and their application to special problems in charging bulk material is illustrated.