A trimethylamine–carbon dioxide draw solution for osmotic engines. Issue 9 (19th April 2018) - Xia, Lingling
Abstract : This study evaluates the pressure retarded osmosis performance of TMA–CO2 for potential use in osmotic heat engines. Power densities up to 18.6 W m −2 were achievable at relatively low pressure (10 bar) using 5 M TMA–CO2 draw solutions. Compared to NaCl control tests, the TMA–CO2 exhibited 20% lower water flux due in large part to its larger molecular size and associated higher solution viscosity and lower diffusion coefficient. Compared to the ammonia‐carbon dioxide draw solution, water flux was comparable but reverse solute flux of TMA–CO2 was nearly one order of magnitude lower. Larger solute size was found to create a performance tradeoff as reduced reverse solute flux improved water flux while higher viscosity and lower diffusion coefficient worsened water flux. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3369–3375, 2018