(406j) An Integrated Approach for the Recovery of Marine Chemicals: Technoeconomic and Sustainability Assessment

Natural brines: sea brine, inland brine and lake brine are a major source for several mineral commodities and chemicals including calcium, sodium, potassium and magnesium salts and bromine. These mineral salts of sodium, calcium, potassium, and magnesium of sea origin are called marine chemicals and have high economic and strategic importance. Land-based minerals are being exploited to recover magnesium and potassium salts. Natural brines and halite rocks have been a conventional source for NaCl production using solar evaporation which accounts for 47% of global common salt production, multi effect evaporation and wet or dry mining technologies. This mineral processing results in a significant amount of by products, which remain unutilized in most cases. The utilization of saline effluent for resource recovery have attracted interest in recent times [1]. Existing brine mining technologies have been listed in literature and these include evaporation with sequential crystallization, membrane-based separation, chemical precipitation, etc. [2].

Sea bittern is a concentrated brine generated from sea salt production using solar evaporation. Several research has been conducted in regards to developing processes to recover some salts from bittern notably sodium, magnesium and potassium salts [2], [3]. The extraction of these valuable compounds is an emerging area of interest with significant potential for resource recovery and environmental sustainability. The reported processes in literature for the recovery of these salts from brine are treated as separate problems and as such there is no generic framework for this resource recovery. This study presents a comprehensive analysis into the development of a framework for optimal separation pathways for the recovery of valuable marine chemicals from brine employing a combination of process optimization and superstructure optimization techniques [4], [5]. A mixed-integer nonlinear programming framework is utilized to explore a diverse set of separation technologies, including evaporation, Centrifugation, Cooling Crystallization etc. The superstructure optimization approach enables the evaluation of various process configurations and the identification of the most cost-effective and environmentally friendly solutions for the recovery of these target chemicals. Techno-economic analysis (TEA) is conducted to assess the economic feasibility of the proposed separation pathways, considering factors such as capital investment, operational costs, and potential revenue streams. Life cycle assessment (LCA) is integrated into the recovery framework to evaluate the environmental metrics of each separation technology, including global warming potentials, human health impacts, ecosystem quality, and resource utilization.

The result of this study highlights the potential of utilizing an integrated process techniques to develop efficient, cost effective and sustainable processes for the recovery of valuable compounds and chemicals from saline systems. The integration of TEA and LCA into the developed framework provides a holistic understanding of the economic and environmental implications of different separation technologies, guiding the selection of the most feasible pathway for the separation and recovery of these marine chemicals.

References

[1] A. Panagopoulos, “Water-energy nexus: desalination technologies and renewable energy sources,” Environ. Sci. Pollut. Res., vol. 28, no. 17, pp. 21009–21022, May 2021, doi: 10.1007/s11356-021-13332-8.

[2] P. Sahu, B. Gao, S. Bhatti, G. Capellades, and K. M. Yenkie, “Process Design Framework for Inorganic Salt Recovery Using Antisolvent Crystallization (ASC),” ACS Sustain. Chem. Eng., Dec. 2023, doi: 10.1021/acssuschemeng.3c05243.

[3] P. Sahu, “A comprehensive review of saline effluent disposal and treatment: conventional practices, emerging technologies, and future potential,” Water Reuse, vol. 11, no. 1, pp. 33–65, Oct. 2020, doi: 10.2166/wrd.2020.065.

[4] K. M. Yenkie, W. Wu, R. L. Clark, B. F. Pfleger, T. W. Root, and C. T. Maravelias, “A roadmap for the synthesis of separation networks for the recovery of bio-based chemicals: Matching biological and process feasibility,” Biotechnol. Adv., vol. 34, no. 8, pp. 1362–1383, Dec. 2016, doi: 10.1016/j.biotechadv.2016.10.003.

[5] J. D. Chea, A. L. Lehr, J. P. Stengel, M. J. Savelski, C. S. Slater, and K. M. Yenkie, “Evaluation of Solvent Recovery Options for Economic Feasibility through a Superstructure-Based Optimization Framework,” Ind. Eng. Chem. Res., vol. 59, no. 13, pp. 5931–5944, Apr. 2020, doi: 10.1021/acs.iecr.9b06725.