as i under stand it,1 purvap unit will produce 2500MTY the unit will cost about 20 million,it can scale to infinity,just by building more purvap units each at around 20 million,to get to 30,000mty you will need 12 purvap units total cost 240 million!
  Now that may appear has costing 40 million more to get the same 30,000mty.BUT ! you can customize your purvap unit/units to produce the purity you/your customers want,at 2500mty ,the legacy unit will only give you 40% of 30,000mty above 2N so about 12,000mty of 2N+ the other 60% is basically sand of lower value,
so we have 12,000mty per year of usable 2n SI,now you have to run it through a chemical purification process with dangerous chemicals ,which involves several steps to get to the higher purity levels.12000mty would be 5 purvap units cost 100 million and no chemicals,less input material and you can scale it to suit you needs.