face facilities. An oil/water separator efficiency will be lower if oil/water emulsion is present in the separator feed (inlet fluid). One alternative to break emulsions is the use of chemical demulsifiers. A demulsifier system (chemical pump injection), installed upstream of the separator, has a capacity to treat up to 40,000 barrels of fluid per day. However, the actual average daily demand is 90%. The following cost expenditure data are below. Determine the present worth, future worth and annual worth capital equivalent. Use 8% interest rate per year. Estimate the unitary cost per barrel ($/bbl) for the use of this chemical, assuming a project life of 10 years. Investment: Chemical injection system: $50,000 (the investment includes 3 positive displacement 0.25 hp pumps, each with electric motor, and storage tanks) Annual expenses Future Electricity: $600 Maintenance and repair: $10,000 Operation: $ 120,000 Chemical consumption and cost: 10 gallons of demulsifier per day at $60 per gallon. Pump overhaul cost $400 per pump at the fifth year. Salvage value at end of the useful life: negligible.