Fabric sourcing capacity

The fabrication cost of a drying unit besides its size depends also on the material of construction it is the lowest for carbon steel. If the process requires a more chemical-resistant material, a cladding may be applied in some cases. In certain drying operations, optimum design of the equipment as well as product-quality requirements calls for the use of not only more durable but also more expensive materials. In general, drying equipment built of 304-stainless steel typically costs from 1.5 to 1.7 times more than that made of carbon steel and 2-3 times more if built of titanium. The cost depends also on the auxiliary equipment, and this is a reason for some uncertainty in cost prediction from literature sources without vendors data. Figure 65.3 presents, as an example, the purchase cost for several dryers in relation to their capacity that is updated to the year 2000 with the M S Index equal to 1089. 

This is a method introduced fairly recently that suits continuous operation particularly well, such as is common in paper, metal coil and fabric coating. Ideally it should be part of the original equipment since it needs to exclude air (as a source of oxygen) from the evaporation zone and this is a function not easily retrofitted to existing plant. It is very compact so that space near the evaporation zone, often very limited, is kept to a minimum. A measure of the problem is that a skid-mounted module with a plot area of 3 m by 2 m and an overall height of 3.75 m has a solvent capacity of 4501/h (Fig. 2.10). 

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