Transportation of bulk solids

The pneumatic transportation of bulk solids through pipelines has been in existence for over one hundred years. Some of the earlier applications included the vacuum unloading of grain from ships and the extraction of sawdust from timber mills. 

Wypych, P. W., Latest Developments in the Pneumatic Pipeline Transport of Bulk Solids, 5th Int. Conf. on Bulk Materials Storage, Handling and Transportation, Newcastle, IEAust, Proc, 1 47-56 (1995a)... 

P. Marjanovic, Theoretical and practical silo design, Seminar on Storage and Transportation of Bulk Solids, Moreton-in-Marsh, UK, March 1996. 

Originally confined to the shipment of crude raw materials and fuels, the term transportation of bulk solids now applies also to manufactured products, which often become raw materials for other industries. In recent years, increasing tonnages of highly processed, finished chemical products have moved to customers in large bulk units. A useful definition of a bulk shipment is any unit greater than 2000 kg (4000 lb) or 2 m (70 ft ). The containers available range from small portable hoppers of 2-m (70-ft ) capacity to railroad cars of 255-m (9000-ft ) capacity. 

Feeding devices in drying systems for granular feedstocks are identical to those used for the transport of bulk solids but careful selection must be made because not all transport equipment is suitable for handling wet solids, which may have poor flowability. 

Wypych, P.W. (1995) Latest developments in the pneumatic pipeline transport of bulk solids, in Proceedings of the 5th International Conference on Bulk IMterials Storage, Handling and Transportation, lEAust, Newcastle, Vol. 1, pp. 47-56. 

A.W. Roberts, A. Harrison, and J.W. Hayes, Economic Factors Relating to the Design of Belt Conveyors for Long Distance Transportation of Bulk Solids, Bulk Solids Handling. Vol. 5, No. 6, pp.l 143-1149,1985... 

P.W. Wypych and A.R. Reed, The advantages of stepping pipelines for the pneumatic transport of bulk solids. Powder Handling Processing, 2 (19W) 217-221. 

Figure 3.14 Covered hopper car, used for rail transport of bulk solids. ButskykhRoman/Shutterstock.com.

A.J. Stepanoff, Gravity Flow of Bulk Solids and Transport of Solids in Suspension, Wiley, New York, 1969. 

Pneumatic conveying belongs to the well established processes for transporting a vast variety of bulk solids. Especially in the handling of granular polymers it is used extensively. Nevertheless, the problem of product degradation due to attrition is unresolved to date. This is partly due to the fact that research was focused on different topics like bend erosion or pipe wear [1,2]. But with the increas-... 

Stairmand, C. j. (1951) Trans. Inst. Chem. Eng. 29, 356. Design and performance of cyclone separators. Stepanoff, a. j. (1969) Gravity Flow of Bulk Solids and Transport of Solids in Suspension (Wiley). Sterbacek, Z. and Tausk, P. (1965) Mixing in the Chemical Industry (Pergamon). 

Chemical manufacture Fluid transport Handling of bulk solids Size reduction and enlargement Heat generation and transport Distillation Gas absorption Bioreactions... 

Different conveyors such as the belt, chain, and screw types, as well as pneumatic equipment, are used to transport bulk powdered foods. Conveyor belts are used for movement of different types of bulk solids at long distances. The belt and its load are supported on idlers on both conveying and return sections. The material can be discharged over the end of the belt either by using a diagonal scraper, by tilting one or more of the idler pulleys, or by using a tripper. 

Fig. 4 Role of xylulose-borate complexation in the co-iimnobilized enzyme system. When sodium tetraborate (borax) is added to solution, it dissociates into tetrahydroxyborate (borate, B) ion and boric acid. In the pellet interior, higher pH favors tighter xylulose-borate binding, which effectively reduces the xylulose concentration in the interior and forces the isomerization forward. In the bulk, the lower pH has an uncoupling effect on the Xu-B complex, making the dissociated xylulose readily available to the yeast. Removal of xylulose via fermentation further forces dissociation of the xylulose-borate complex. Dashed lines represent transport of species solid lines represent reactions... 

Stepanoff, A.J. (1964). Phunping solid-liquid mixture. Mechanical Engineering 86(9) 29-35. Stepanoff, A.J. (1965). Pumps and blowers Two-phase flow, ed. 2. Wiley New York. Stepanoff, A.J. (1970). Gravity flow of bulk solids and transportation of solids in suspension. Wiley New York. 

The issues listed above are some of the important considerations when laying out a plant incorporating belt conveyors, or in deciding whether a belt conveyor or system of conveyors is the best solution for a given application of bulk solids transport. The following alternative devices are often worthy of consideration. 

Theoretical and experimental work on the transport of bulk material started in earnest around 1960. A collection of experimental and theoretical work was presented at a joint ASME-CSME Conference on Mechanics Applied to the Transport of Bulk Materials [1] and the U.S.-Japan seminars on Continuum Mechanical and Statistical Approaches in the Mechanics of Granular Materials [2]. Books on particulate solids have been written by Orr [3] and Brown and Richards [4]. Review articles have been published by Richards [5], Wieghardt [6], and Savage [7]. Some of the pioneering work on flow of bulk solids was done by Jenike [8, 9]. 

Mainwaring, N. J. and Reed, A. R. (1987) An appraisal of Dixon s slugging diagram for assessing the dense phase transport potential of bulk solid materials, in Proceedings of Pneumatech 3, pp. 221-234. 

Stepanoff, A. J. 1969. Gravity flow of bulk solids and transportation of solids in suspension. New York Wiley. 

Bulk handling of solids is usually accomplished by use of bins and conveyors. But solids may also be transported by suspension in a liquid or a gas. The latter method of transport is the subject of this book. Often, the suspension of solids in a liquid is not desirable from a process standpoint. The solids may dissolve or change character in the liquid, or the presence of the liquid may not be desirable in some high-temperature process. In these cases, one must resort to gas-solid transport or pneumatic transport of the solids for movement. 

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