Abstract
Lime based causticization of green liquor (GL, rich in Na2CO3) to white liquor (rich in NaOH) followed by lime recycling in pulp and paper mills is an energy intensive and environmentally hazardous technique. Recently membrane electrolysis is proposed to be an alternative to this, where use of single cation exchange membrane (CEM) between two electrodes limits the processing volume of the feed stream. This can be overcome through BMED (bipolar membrane electrodialysis) technique, where multiple cell pairs can be applied to process larger feed volume. Current report investigates optimization of NaOH production from synthetic-GL using a BMED stack with variation of current density (25, 50, 75 and 100 mA·cm−2), GL concentration (100%, 75%, and 50% v/v), and feed temperature (27, 40 and 50 ℃) along with multiple cell pair arrangement (1, 2 and 3). With 50 mA·cm−2, ~1.6 mol·L−1 of NaOH could be produced from 500 mL of synthetic-GL in 5 h using a three-cell pair BMED setup (effective area of 32 cm2 per cell pair), where current efficiency and energy consumption estimates were ~88.0% and ~4.7 kWh·kg−1, respectively. Under identical conditions, NaOH production performance from industrial-GL was quite comparable (deviation < 5%) to that of synthetic-GL.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
