Cost for Solvent Without Recycling
reagent cost of new solvent per year =
= (liters of solvent used per year) * (reagent cost of solvent per liter)
cost of shipping and handling for new solvent per year =
= (liters of solvent used per year) * (cost to ship and handle per liter)
total cost of purchasing new solvent per year =
= (reagent cost of new solvent per year) + (cost of shipping and handling per year)
solvent disposal cost per year =
= (liters of solvent disposed of per year) * (cost per liter to dispose of solvent)
where:
• The solvent volume disposed of per year is often less than the amount used due to evaporation and other factors.
total cost for solvent per year =
= (total cost to purchase new solvent per year) + (total cost to dispose of used solvent per year)
Cost for Operating Still
total cost for operating still per year =
= (labor cost to operate per year) + (maintenance cost per year) + (electricity costs per year) + (water costs per year)
Cost for Still Bottom Disposal
still bottom volume in liters =
= (liters of solvent used per year) * ((100 - (percent still recovery))/100)
cost of disposing of still bottom =
= (still bottom volume in liters) * (cost per liter to dispose of solvent)
cost of new solvent to be purchased =
= (total cost of purchasing new solvent per year) * ((100 - (percent still recovery))/100)
total cost of still bottom =
= (cost to dispose of still bottom contents) + (cost to purchase new solvent)
Capital Cost for Recycling
total capital cost for still =
= (cost for still) + (cost for installation materials) + (cost for installation labor)
Bottom Line for Recycling
total cost of recycling per year =
= (total cost to operate still per year) + (cost to dispose of still bottom per year) + (cost of any chemicals needed to reconstitute solvent per year)
annual operational savings from recycling =
= (total cost of solvent per year without recycling) - (total cost of recycling per year)
payback period in years to cover capital expense from operational savings =
= (total capital cost of still) / (annual operational savings from recycling)
