Nitrogen inerting, cost

Due to relatively low UV radiant power of these types of lamps, nitrogen inerting has to be used,i which increases the operating cost. 

Based on theoretical considerations, the formation of dross is five to seven times greater for lead-free alloys compared to 60Pb-40Sn or eutectic Sn-Pb alloys because of the increased tin content and soldering temperature [7]. In certain minimum cases, the dross doubles or triples. In addition to better yield and increased reliability, substantial reductions in dross formation to reduce cost are another reason for implementing nitrogen inerting. 

To produce the melted polymer, the polymer chips, rods, marbles, or sheets are heated forming a melted pool of material. In order to minimize oxidation, the melted polymer is blanketed by an inert gas such as nitrogen or argon. The fluidity (inverse of viscosity) of the melt increases with increased temperature as does the cost to provide the necessary energy and tendency for unwanted reactions to occur. Thus, the polymer melt is generally assisted to and through the spinneret by means of an extruder, which may also be used to supply some or all of the heating. 

Since molecular nitrogen is inert, its reaction with hydrogen requires very severe conditions and a catalyst. An iron catalyst is used. High pressure favors the formation of products, but an increase in temperature will shift the equilibrium in the opposite direction. Plants will thus operate under conditions that represent the most favorable balance between operating costs and capital investment. 

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