Distributor distribution quality

The type of distribution to select depends on the sensitivity of the tower performance to the liquid distribution as discussed earlier. Norton s [83] data indicate that the sensitivity of tower performance to liquid distribution quality depends only on the number of theoretical stages in each bed of packing achierable at its System Base HETP [83]. Tower beds of high efficiency packing are more sensitive to liquid distribution quality than shorter beds of medium efficiency packing [83]. It is important to extend the uniformity of the distributor all the way to within one packing particle diameter of the tower wall [85]. 

To quantify the quality of liquid irrigation, the correlation uses the distribution quality rating index. Typical indexes are 10 to 70 percent for most standard commercial distributors, 75 to 90 percent for intermediate-quality distributors, and over 90 percent for high-performance distributors. Moore and Rukovena present a method for calculating a distribution-quality rating index from distributor geometry. Their method is described in detail in their paper as well as in Kister s book (.Distillation Operation, McGraw-Hill, New York, 1990). 

A vapor-distributing support (Fig. 3.10) is a flat perforated plate containing perforated vapor risers. Liquid descends through the floor perforations, while vapor rises through the riser perforations. The bottom portion of the vapor risers is unperforated, so that vapor is injected above the liquid pool on the plate. Sumps are optional and recommended (289) where liquid inventory is to be reduced. The vapor-distributing support combines two internals (a vapor distributor and a support plate) into one. Compared to a vapor distributor, this saves both vertical space and internals costs. On the other hand, obstruction of perforations by pieces of packing and possible liquid overflow into risers may make its vapor distribution quality somewhat lower. 

Lantis Eyewear Corporation is a leading designer, marketer, and distributor of quality eyewear products, primarily sunglasses and optical frames. Its licensed and proprietary brand name products are known throughout the United States and internationally. Lantis distributes through mass merchants, department stores, dmg stores, and eyewear specialty stores. The firm ships about 30 million units each year. 

This case addresses the situation of a manufacturer and distributor of quality footwear and apparel. The company had 112 million in annual sales and experienced rapid sales growth. The company manufactured 25% of its products in Southern California, and the other 75% was manufactured in Mexico, Costa Rica, Australia, New Zealand, and China. The company relied heavily on contract manufacturers. With its growth, it had concerns regarding managing freight costs and distribution related performance. 

Liquid distribution in a packed bed is a function of the internal vapoi/liquid traffic, the type of packing employed, and the quality of the liquid distributors mounted above the packed bed. Vapor distribution is controlled by the internal vapor/liquid traffic, by the type of packing employed, and by the quality of the vapor distributors located below the packed beds. 

The use of V-notches in a trough wall for overflow is more sensitive to leveling problems than the other designs, and for the same %- to Me-in. level tolerance produces a more severe non-uniform flow distribution. The quality of distribution from a V-notch is poor compared to the other types of trough distributor, but does have advantages in slurry systems [131]. It should not be used for critical distillation applications, but is good for heat transfer and where solids are in the system. 

The quality grading system relates to uniformity of distribution across the tower cross-section, where 100% quality indicates ideal uniform distribution. Distributors are designed to suit the system, particularly the packing type and size. 

Good distribution of gas over the whole cross-section of the bed may often be difficult to achieve, although this is enhanced by ensuring that the pressure drop across the distributor is large compared with that across the bed of particles. In general, the quality of gas distribution improves with increased flowrate because the pressure drop across the... 

General Generally, from a macroscopic point of view, maldistribution can be divided into two different phenomena (Stanek, 1994). The first one is small-scale maldistibution, which is connected mainly to the so-called preferred paths. It is the case where the liquid follows specific paths through bed and travels with velocities considerably higher than the mean. The same phenomenon is characterized as chaneling. The second case is large-scale maldistribution, which is connected to the nonhomogeneous (nonunifonn) initial distribution of the liquid and is referred to as wall effects. The concepts of distributor quality and liquid maldistribution in fixed beds are frequently found in the related technical literature, and these concepts are connected to each other—the better die distributor quality, the better the liquid distribution and flow into bed (Klemas and Bonilla, 1995). 

Three interrelated trends of globalization among chemical producers and customers, increasing QHSE (quality, health, safety, and environment) standards, and outsourcing by the producers and customers are currently shaping the chemical distribution industry, offering distributors considerable opportunities for competitive differentiation. 

Packed-tower efficiency and turndown are strongly dependent on the quality of initial liquid distribution. Uneven distribution may cause local variations in the liquid/gas ratio, localized pinch conditions, and reduced vapor-liquid contact. Figure 14 shows two common liquid distributor types, the ladder type (shown as the top distributor) and the orifice type (shown as the redistributor). The ladder type is a horizontal header of pipes, which are perforated on the underside. The orifice type is a flat perforated plate equipped with round or rectangular risers for gas passage. Other common types of distributors are a header equipped with spray nozzles (spray distributor) and a header of horizontal channels, with V notches cut in the vertical walls of the channels (notched-trough distributor). 

Barrington Chemical Corp BASF Corp Brenntag Inc Charkit Chemical Corp Charles Bowman 8c Co Delta Distributors Inc EM Industries Inc Fisher Scientific George Uhe Co Inc Hawkins Chemical Inc Helm New York Inc JT Baker Inc Kraft Chemical Co Mutchler Inc Particle Dynamics Inc Penta Manufacturing Co Seltzer Chemicals Inc Spectrum Quality Products Inc Takeda Pharmaceuticals North America Inc Triple Crown America Voigt Global Distribution LLC Vopak USA Inc... 

Brenntag Inc Delta Distributors Inc DSM Fine Chemicals Inc Penta Manufacturing Co Spectrum Quality Products Inc Triple Crown America Voigt Global Distribution LLC Vopak USA Inc... 

The particles of the bed of an analytical column are held by the column wall and by the porous frits at the column top and column end. Specific frit systems have been developed by column manufacturers to enable a homogeneous distribution of the flow across the column. Wide bore preparative columns contain distributors at both ends for optimum sample distribution. Both the quality of the frits and the distributors significantly affect the performance of a chromatographic column. While for analytical columns the bed is supported by friction between the column wall and the packed particles, the particles of wide bore preparative columns are subjected to a much higher mechanical stress. 

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