Your company has 1 MMM pounds per year of ethane, which is currently being produced at your Gulf Coast plant and sold for $0.07/lb in 2000. Your team has been asked to evaluate the economic viability of the Dow process for your plant, as a way of upgrading your product and increasing your sales revenue. Your job is to determine the economic optimum design, maximizing the net present value (NPV) of the project. You may consume all or part of the ethane, which is available. Based on past experience, you know that you will have to be able to defend any decisions you have made throughout the design, and the best defence is economic justification. Your plant design must be backed up with a rigorous simulation of the entire process, with all recycle loops closed. Your marketing organization believes they can sell ethylene for $0.25/lb in 2001 dollars. Pipeline oxygen in your area costs $0.02/lb. It would be a good idea to test the sensitivity of the optimum plant design and economics to uncertainty in the selling prices of the product and the raw material. The plant design should be as environmentally friendly as possible. Recover and recycle process materials to the maximum economic extent. Also, energy consumption should be minimized, to the extent economically justified. The plant design must also be controllable and safe to operate, an important consideration with oxygen and hydrocarbons. Remember that you will be there for the start-up and will have to live with whatever design decisions you have made.