Volume 5: Innovative Solutions for Energy Transitions: Part IV

Development of Integrated High-Gravity-Electrodeionization (HiG-EDI) Technology for CO2 Capture, Waste Stabilization and Wastewater Reclamation Tse-Lun Chen, Po-Chih Tseng, Shu-Yuan Pen, Pen-Chi Chiang

Abstract

A two stages process integration of high-gravity (Higee) rotating packed bed (RPB) and resin wafer electrodeionization (RW-EDI) technology was developed for CO2 mineralization, waste utilization and water reclamation. To stabilize and upgrade the properties of the municipal solid waste incineration fly ash (MSWI FA), accelerated carbonation was performed to convert calcium-bearing species into calcium carbonates via a Higee RPB. The direct and indirect carbonation process were consecutively operated via a RPB while the leachate (water washing liquid) from MSWI FA carbonation with high content of chloride ions was reclaimed via a RW-EDI process. In this study, the carbonation conversion of MSWI FA in direct carbonation using Higee process was evaluated along with CO2 capture capacity, CaCO3 formation and energy consumption. Several key factors including rotating packed bed and liquid-to-solid ratio (LSR) were evaluated through experimental design. In addition, the energy consumption and productivity of MSWI FA leachate using RW-EDI was evaluated. Results indicate that the carbonation conversion was increased as raising the rotating speed and lower LSR. The maximal carbonation conversion of 89.81 % was found at rotating speed of 1000 rpm and LSR of 10. To remove the residual calcium ions in the leachate, the indirect carbonation was conducted in a RPB. The outlet CO2 concentration, pH value, calcium ions concentration and conductivity of leachate were decreased as over reaction time. The maximal CO2 capture efficiency was found at the reaction time of 5 minutes. Furthermore, the results show that the relationship between energy consumption and productivity of MSWI FA leachate treatment via RW-EDI was negative correlation. The energy consumption of RW-EDI for MSWI FA leachate treatment was found to be 1.49–3.61 kWh/m3 with productivity of 12.82–17.09 L/hr/m2 . It suggested that the integrated HiG-EDI system offers the potential for an abundant source of CO2 capture, MSWI FA stabilization and fresh water from FA leachate treatment, which should be viewed as a crucial component in the portfolio of CO2 capture, waste stabilization and water reclamation.

Keywords High-gravity rotating packed bed, Resin wafer electrodeionization, municipal solid waste incineration fly ash, CO2 mineralization, water reclamation