Liquid–Liquid Extraction of Formic Acid with 2-Methyltetrahydrofuran: Experiments, Process Modeling, and Economics

Abstract

Formic acid (FA) is an interesting hydrogen (H 2 ) and carbon monoxide (CO) carrier that can be produced by the electrochemical reduction of carbon dioxide (CO 2 ) using renewable energy. The separation of FA from water is challenging due to the strong (cross)association of the components and the presence of a high boiling azeotrope. For the separation of dilute FA solutions, liquid–liquid extraction is preferred over conventional distillation because distilling large amounts of water is very energy-intensive. In this study, we use 2-methyltetrahydrofuran (2-MTHF) to extract FA from the CO 2 electrolysis process, which typically contains <20 wt % of FA. Vapor–liquid equilibrium (VLE) data of the binary system 2-MTHF–FA and liquid–liquid equilibrium (LLE) data of the ternary system 2-MTHF–FA–water are obtained. Continuous extraction and distillation experiments are performed to test the extraction power and recovery of 2-MTHF from the extract. The VLE and LLE data are used to design a hybrid extraction and distillation process to produce a commercial grade product (85 wt % of FA). A detailed economic analysis of this hybrid extraction–distillation process is presented and compared with the existing FA separation methods. It is shown that 2-MTHF is a cost-effective solvent for FA extraction from dilute streams (<20 wt % FA).

Electrochemical Reduction of CO2 to Oxalic Acid: Experiments, Process Modeling, and Economics

“…Liquid−liquid extraction (LLE) is a well-established separation technique that is used on an industrial scale, e.g., for formic acid and acetic acid extraction. 27 In LLE, the solute (OA) is transferred from one liquid phase (feed) to a second liquid phase (extraction solvent), which has a higher affinity for binding the solute. Typically, a water-immiscible solvent is used to extract the solute from an aqueous solution.…”

Electron Localization and Lattice Strain Induced by Surface Lithium Doping Enable Ampere‐Level Electrosynthesis of Formate from CO2

“…To assess the potential value of the obtained high formate concentrations, a simplified techno-economic analysis (TEA) was conducted based on the previously reported methodology. [2,28,29] Combining the purification and concentration costs to the commercial grade formic acid (85 wt %), the total production cost of our system was calculated as % $169 per ton, which was substantially lower than other electrochemical CO 2 RR systems for producing formate (Table S7), and also comparable to the reported chemical route as $115--$190 per ton, [30] thus suggesting the attractive perspective of our catalytic system.…”

Efficient pretreatment using dimethyl isosorbide as a biobased solvent for potential complete biomass valorization

“…However, to demonstrate its scaling-up potential overcoming the relatively high cost of DMI currently, future investigations will focus on optimization of recycling options, followed up by economic and environmental assessment. 66 In addition, applications on different feedstocks and screening for more selective catalysts to improve the lignin yield and quality will be also performed in the future work.…”