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Direct Reduction Iron Plant. Group Golf Selimos , Blake A. Arrington, Deisy C. Sink, Brandon Ciarlette , Dominic F. (Scribe) Advisor : Orest Romaniuk. Table of Contents. Page 3-4: Motivation Page 5-6: BFD / Design Basis Page 7-8: Process Flow Diagram Page 9 : Energy Recovery
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Direct Reduction Iron Plant Group Golf Selimos, Blake A. Arrington, Deisy C. Sink, Brandon Ciarlette, Dominic F. (Scribe) Advisor: OrestRomaniuk
Table of Contents Page 3-4: Motivation Page 5-6: BFD / Design Basis Page 7-8: Process Flow Diagram Page 9: Energy Recovery Page 10: Environmental Considerations Page 11-15: Economics Page 16: Recommendations Page 17: Summary
Motivation • Natural Gas cost is expected to decrease further
Motivation • With natural gas prices trending down and an abundance of it available in Wiliston ND, a Midrex plant makes sense economically. • The NPV for this plant is $1,030,000,000 • Midrex process is more cost efficient and environmentally friendly than conventional blast furnaces.
Design Basis • 2700 tons/day of natural gas feedstock will be supplied for process and fuel • Natural gas and steam are the main sources of H2 • Air is used as the main source of N2 • Supply the back-end ammonia plant with H2 and N2 in a 3:1 molar ratio to make 3600 TPD of NH3
Process Flow Diagram 1 5 10 3 8 2 4 7 9 6
Energy Sinks and Loads: Heat Exchangers • Excess energy from the flue gas is used to heat the feed of gas in 1076º F 75 psi 615º F 14.7 psi 724º F 14.7 psi 420º F 14.7 psi 1878º F 14.7 psi 724 ºF 14.7 psi 77º F 14.7 psi 180º F 75 psi Q=113 mmBtu/hr Q=27 mmBtu/hr
Environmental Considerations • Midrex plants are designed with the goal of minimizing water, air, and noise pollution. • In comparison to traditional blast furnaces, Midrex plants have much lower CO2 emissions due to using natural gas instead of coal, as well as having a reformer that can handle larger amounts of recycled CO2 than the average steam-methane reformer. • 153 ton/year of CO2 emissions
Recommendations • We recommend proceeding with the completion of the Midrex plant at the Wiliston ND location. • We recommend changing the process so that there is no recycled stream going into the combustion chamber of the reformer. Instead, burn the CO and CH4 with some O2, then dry the stream to remove the water and send the remainder of the stream over to team India as CO2. Natural gas is the cheapest commodity in this plant so it makes sense to use a little more of that for the combustion rather than implementing a pricy MDEA system to remove the CO2 and allow us to burn the little bit of recycled CO and CH4 that’s left.
Summary • The process starts with 2,700 tons/day of natural gas feedstock and will give enough H2 and N2 to the back-end ammonia plant to produce 3,600 tons/day of NH3 • Natural gas feedstock and convection section optimization will reduce expenses and payback period • Projected payback period is 6.8 years • Net present value is 809 million USD (20 years)