Pneumatic conveying operating conditions

Plate exchangers, 189,195 Plates, fractionating. See Trays Pneumatic conveying, 71-76 dense phase transfer, 74 equipment, 72,73,75 flow rates, 72 operating conditions, 73 pilot plant, 74... 

Pneumatic Conveying Dryers A gas-solids contacting operation in which the sohds phase exists in a dilute condition is termed a dispersion system. It is often called a pneumatic system because, in most cases, the quantity and velocity of the gas are sufficient to hft and convey the solids against the forces of gravity and friction. (These systems are sometimes incorrectly called flash dryers when in fact the moisture is not actually flashed off. True flash dryers are sometimes used for soap drying to describe moisture removal when pressure is... 

Dilute-phase pneumatic conveying is not an energy-efficient way of conveying, since generally considerable horsepower is needed to provide the motive air or gas. Dilute-phase pneumatic conveying, however, is easy and convenient to put into operation, even if often it does not work at optimum conditions, mostly owing to poor understanding of the overall concept of the process. 

The layout of the piping systems has many important factors in pneumatic conveying. One should keep the flow path as the most direct between two points. Bends should be eliminated as much as possible. Care should be taken in the design that the distance after a feed point before the first bend is inserted in a minimum of 3 meters (10 feet) when two-phase conditions are present. If the flow is dilute or dense, this distance is not crucial. The two-phase condition tends to cause a sloshing of the solids in the bend in an unsteady condition. This sloshing behavior causes plugging and other upsets in the operation of the pneumatic conveying systems. As noted before, one should at all costs avoid more than two bends in quick succession. 

The motive power is provided by the primary driver, which generates the gas (typically air) velocity required to transport material within a pneumatic-conveyor system. Therefore, the efficiency of the conveying system depends on the primary driver s operating condition. 

The accurate determination of minimum transit conditions for a particular product and application is an equally essential requirement for many areas of dilute-phase pneumatic conveying (e.g. system ign optimisation of operating conditions minimisation of product damage, pipe nd wear and power consumption). Consequently, a considerable amount of research work also has been undertaken for many years resulting in a wide selection of correlations. Also, based on various comparadve- pe studies, e.g. [7-9], several models have been labelled as best bi s . 

This reconstruction was done in operational conditions of the power plant within a short stop of only 10 days. Now since operation has started for more than 18 months, the pneumatic conveying system is working with a capacity higher than 2 x 50 t/h and a conveying distance of max. 875 m without any problems. 

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