How do you estimate equipment costs in early-stage design?

Equipment cost estimation methods: Vendor quotes - most accurate but time-consuming. Capacity factoring - scale from known cost using exponent: Cost_2 = Cost_1 x (Capacity_2/Capacity_1)^n where n is typically 0.6 for many equipment types. Cost curves - published correlations (Peters & Timmerhaus, Towler & Sinnott). Software - ICARUS, Aspen Economic Analyzer. Historical data - company cost databases adjusted for time and location. Adjustment factors: material factor (SS vs. CS), pressure factor, location factor (Gulf Coast index), and inflation (CEPCI or similar). Equipment cost is typically 40-60% of total installed cost. Factor methods (Lang factor, Hand factors) estimate total plant cost from equipment cost. Accuracy: early estimate +/- 30-50%, detailed +/- 10-15%.