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Ethanol dehydration performance of three types of commercial-grade zeolite permselective membranes
Citation:
Vane, L., F. Alvarez, V. Namboodiri, AND M. Abar. Ethanol dehydration performance of three types of commercial-grade zeolite permselective membranes. Journal of Chemical Technology and Biotechnology. John Wiley and Sons, LTD, , Uk, 97(8):1966-1977, (2022). https://doi.org/10.1002/jctb.7141
Impact/Purpose:
In 2015, the U.S. Environmental Protection Agency (EPA) finalized a new Definition of Solid Waste Rule which highlighted the potential environmental benefits of reclaiming and reusing spent industrial solvents. Prompted by the financial and environmental benefits of reusing solvents, the recycling of many solvents has increased. One reason solvents are not reused is that reuse requires the application of separation technologies and energy to recover and purify the solvents from the spent material. Because many of the solvents targeted for increased recycling in the Definition of Solid Waste Rule form difficult-to-separate mixtures with water, this work focused on energy-efficient solvent drying technologies that are able to separate solvent-water mixtures, particularly the membrane processes of pervaporation (PV) and vapor permeation (VP). Several types of water-selective membrane materials are now commercially available, but performance data is limited, particularly under comparable conditions. This is particularly true of two recently commercialized membranes based on chabazite (CHA) and T-type zeolites. The objective of this work was to evaluate commercial-grade samples of CHA and T-type zeolite membranes for the removal of water from ethanol/water mixtures along with a commercial-grade NaA zeolite membrane, the benchmark inorganic PV membrane material. The CHA sample had the highest initial PV water permeance (6820 GPU) and water permselectivity (3430) with 5 wt% water in ethanol at 50°C. Initial NaA benchmark membrane performance was only slightly lower (6060 GPU and 3260) while the T-type membrane had the lowest initial permeance and selectivity (4260 GPU and 1090). However, performance of each membrane declined over time, most notably for the NaA membrane, for which water permeance after 39 days of PV testing had fallen to about a third of the initial value. The T-type membrane exhibited the steadiest PV water permeance, but the most variable ethanol permeance. The overall PV performance of the three membranes largely overlapped the predicted range for T-type membranes. That level of performance generally exceeds the anticipated ethanol drying performance of non-zeolitic PV membranes, but is less than that predicted for NaA and CHA membranes. The present results with the CHA membrane, along with other recent reports with CHA membranes, refine earlier predictions of the ethanol dehydration performance of that type of zeolite. The changing performance with time must be understood to properly design a solvent dehydration system.
Description:
This product will describe for the Regions and Program Office advanced separation technologies for waste solvent recovery and reclamation. This product supports the Remanufacturing Exclusion in the new Definition of Solid Waste Rule as well as the generator-controlled exclusion as it applies to in-house reclamation of industrial solvents. The Remanufacturing Exclusion was intended, in part, to encourage the reuse/re-processing of 18 higher-value hazardous spent industrial solvents in the pharmaceutical, paint and coating, plastic and resin, and basic organic chemicals sectors. The product will communicate the results from benchmarking studies of commercial membranes for drying industrial solvents to provide performance parameters for membrane selection and to improve reclamation process decision-making. The product will document the demonstration of advanced separation technologies for waste solvent recovery and reclamation in the form of a user-oriented tutorial and journal article. The research will incorporate Regional solvent reclamation efforts and priorities and form collaborations with recycling equipment manufacturers, solvent remanufacturers, and solvent users to improve likelihood of sustainable technology adoption and tangible increase in solvents being reused. The product will be used by the Regions to engage industries in solvent reclamation activities.
URLs/Downloads:
DOI: Ethanol dehydration performance of three types of commercial-grade zeolite permselective membranes
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