Evaluating the Techno-Economic Feasibility of Forward Osmosis Process Utilizing Low Grade Heat: Applications in Power Plant Water, Wastewater, and Reclaimed Water Treatment
- Carnegie Mellon Univ., Pittsburgh, PA (United States)
Recovering and using uncoverted heat produced during electric power generation holds potential to significantly improve the efficiency of the electric power industry. One potential use of this low-temperature waste heat is on-site water treatment using waste heat driven processes to comply with the 2015 Effluent Limitation Guidelines for the Steam Electric Generating Sector. Ammonia-carbon dioxide forward osmosis (NH4HCO3 FO) is a two-step waste heat driven process that involves a membrane separation process in which an osmotic pressure gradient created by an NH4HCO3 draw solution is used to pull water across the membrane and a distillation column to regenerate the NH4HCO3 draw solution. In this work we estimate the quantity, quality, and spatio-temporal availability of waste heat produced at U.S. coal, nuclear, and natural gas plants. We combine these estimates of waste heat availability with a techno-economic optimization model of NH4HCO3 FO in order to assess the potential of NH4HCO3 FO to treat flue gas desulfurization (FGD) wastewater, gasification wastewater, and boiler feedwater. We find that in 2012, 18.9 billion GJ of waste heat was discharged from the U.S. coal, natural gas, and nuclear fleet, although only 900 million GJ of waste heat was discharged at temperatures suitable for NH4HCO3 FO. A maximum of 1.9 billion m3/yr of water could be produced using this waste heat to drive a NH4HCO3 FO. The costs of waste heat driven NH4HCO3 FO for FGD and gasification wastewater treatment to zero liquid discharge (ZLD) and boiler feedwater treatment are 2.20-2.40/m3 and 0.35-0.65/m3, respectively. With mechanical vapor compression and crystallization for ZLD wastewater treatment and reverse osmosis for boiler feedwater treatment as the cost benchmark technologies, waste heat driven NH4HCO3 FO is cost competitive for ZLD wastewater treatment, but not boiler feedwater treatment.
- Research Organization:
- Carnegie Mellon Univ., Pittsburgh, PA (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- DOE Contract Number:
- FE0024008
- OSTI ID:
- 1415992
- Report Number(s):
- DOE-CMU-24008-FINAL
- Country of Publication:
- United States
- Language:
- English
Similar Records
Energy Efficient Waste Heat Coupled Forward Osmosis for Effluent Water Management at Coal-Fired Power Plants
Water treatment capacity of forward osmosis systems utilizing power plant waste heat