Optimum vapor line size

For vapor line, required horsepower for line pressure drop is calculated by following equation  

For vapor flow, line pressure drop, dpL, is calaculated by following equation  

Substitute Eq, (32b) and Eq. (34) into Eq. (31). Let differentiation of CT with respect to line inside diameter, d, to zero. After some algebra manipulation, follow equation for the optimum vapor line size is obtained. 

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Optimum single phase (liquid or vapor) line size is discussed in this section. It only applies to cases where Ime pressure drop has a cost to plant. For example, pump or compressor is used to overcome the line pressure drop. It is not applicable to eases where line pressure drop Is free, such as a pressure let down line. 

Optimum liquid and vapor line size equations are presented in following sections. Nomenclatures, assumptions, and equations of the symbols used in this section are explained as follows ... 

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