10Supercritical Water Oxidation (SCWO) reactors can process waste effluents achieving high 11 conversions, but the required extreme pressure and temperature operational conditions entail 12 high-energy operational expenditure. SCWO has the potential to be considered a clean energy 13 generation process, as the process effluent is a high temperature, high pressure stream with a high 14 enthalpy content that can be converted to heat and shaft work. This ensures the self-sustained 15 reaction and can generate excess shaft power to drive both the high-pressure pump and the air 16 compressor. On the contrary, an efficient heat and power recovery from SCWO reactors outlet 17 streams using conventional procedures presents several problems. First, Rankine cycles impose 18 indirect heat transfer to the working fluid and are unable to recover the pressure energy and 19 second, direct expansion of the effluents entails costly development of specific, efficient 20 expansion equipment. 21In this work, we investigate the options for energy recovery of SCWO reactors coupled with 22 commercial gas turbines (GT). SCWO outlet streams are mainly composed of water, nitrogen and 23 carbon dioxide. These operating values nearly resemble the well-known and already-implemented 24 GT steam injection procedures. The temperature of the flue gases (approx. 500 ºC) and the direct 25 shaft work usage offers adequate energy integration possibilities for both feed preheating and 26 compression. The wide range of commercially available GT sizes enables process scaling. 27
Biological municipal wastewater treatments lead to high sludge generation and long retention times, and the possibilities for recovery of the energy content of the input waste stream are very limited due to the low operating temperature. As an alternative, we propose a sequence of exclusively physicochemical, non-biological stages that avoid sludge production, while producing high-grade energy outflows favoring recovery, all in shorter times. Ultrafiltration and evaporation units provide a front-end concentration block, while a supercritical water oxidation reactor serves as the main treatment unit. A new approach for energy recovery from the effluent of the reactor is proposed, based on its injection in a gas turbine, which presents advantages over simpler direct utilization methods from operational and efficiency points of view. A process layout and a numerical simulation to assess this proposal have been developed. Results show that the model process, characterized with proven operating parameters, found a range of feasible solutions to the treatment problem with similar energy costs, at a fast speed, without sludge production, while co-generating the municipality’s average electricity consumption.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.