Identification and Screening of Potential Organic Solvents for the Liquid–Liquid Extraction of Aromatics

Abstract

There is increasing focus on the replacement of commonly used solvents in the liquid−liquid extraction of aromatics with solvents that result in improved process economics as well as reduced risk in terms of health, safety, and environment. In this work, a selection of organic chemicals are proposed for further study as replacement solvents that meet the technological requirements for the process of aromatics extraction from alkanes and have not been conventionally considered previously for this application. There were 52,654 organic chemicals screened with the use of a search algorithm based on the process requirements in terms of physical properties, capacity, selectivity, and performance index. Nine organic chemicals were identified (not being previously considered) that met all the criteria imposed by the search algorithm. A risk assessment further screened the identified chemicals, filtering out the potential solvents with adverse impacts on health, safety, and environment. Process designs were developed with the use of ASPEN plus in order to ascertain the effects of solvent choice on process economics via the use of total annual costs. The screening process in this work produced significant insights due to its holistic approach. The incorporation of factors such as solvent price, solvent loss, utilities, capital costs, health, and environmental impact showed that several of the solvents identified may be sustainable and cost-effective alternatives to conventionally used solvents. This highlights the need for a robust and broad perspective in considering the impact of solvent choice.

Ternary Liquid–Liquid Equilibrium Data for the n-Heptane + Toluene + (Butane-1,4-diol or Glycerol) Systems at 298.2, 313.2, and 333.2 K and 0.1 MPa

“… A replacement solvent that can fulfill the commercial requirements of an extraction process and is an improvement over conventional solvents requires a comparison over a large spectrum of factors. A consolidated screening methodology over a data set of more than 50 000 organic chemicals that considered solvent properties, extraction capabilities, price, and impact on health, safety, and environment, as well as process energy consumption and economics, identified propane-1,2,3-triol (glycerol) and 1,4-butanediol as potentially suitable commercial alternatives. This screening process utilized UNIFAC (LL) to determine the selectivity of the chemicals in the data set, assessing possible solvents that demonstrated selectivities greater than unity.…”

Liquid–Liquid Extraction of Toluene from n-Heptane Using Butane-1,4-diol + 2-Methyl-pentane-2,4-diol Liquid Mixtures

“…The consideration of numerous factors required to evaluate the suitability of alternative solvents requires a multifaceted approach. The authors here previously developed and applied a solvent screening methodology that evaluated the suitability of more than 50,000 chemicals based on physical properties, modeled extraction capability, price, process utilities, capital costs, as well as impact on health, safety, and the environment . The study identified propane-1,2,3-triol (glycerol), 1,4-butanediol, as well 2-methyl-2,4-pentanediol as potential commercial and sustainable alternatives.…”

“…The authors here previously developed and applied a solvent screening methodology that evaluated the suitability of more than 50,000 chemicals based on physical properties, modeled extraction capability, price, process utilities, capital costs, as well as impact on health, safety, and the environment. 19 The study identified propane-1,2,3-triol (glycerol), 1,4-butanediol, as well 2-methyl-2,4-pentanediol as potential commercial and sustainable alternatives. In the absence of experimental data, UNIFAC (LL) was used to evaluate if the selectivity of all the solvents considered in the database was greater than unity.…”

Ternary Liquid–Liquid Equilibrium Data for the n-Nonane + o-Xylene + (Butane-1,4-diol or Glycerol) Systems at (298.2, 313.2, 333.2) K and 0.1 MPa

“…The authors here have previously conducted a screening process that evaluated the potential use of more than 50 000 organic chemicals in this particular application . Various factors such as solvent price, process energy consumption, extractor design and capital costs, extraction capability of solvent, as well as impact on health and environment were considered.…”

“…18 The authors here have previously conducted a screening process that evaluated the potential use of more than 50 000 organic chemicals in this particular application. 19 Various factors such as solvent price, process energy consumption, extractor design and capital costs, extraction capability of solvent, as well as impact on health and environment were considered. The study identified propane-1,2,3-triol (glycerol) and butane-1,4diol as being able to potentially compete with commercial alternatives while offering benefits in terms of health and safety.…”