Geological Society of America

T133 Use of Oil and Gas Production Wastes Outside the Oil Field: Lab, Field, and Modeling Studies of Potential Impacts

Monday, 23 September 2024
1:30 PM - 5:30 PM
211B

ION EXCHANGE PROCESSES FOR CO2 MINERALIZATION USING INDUSTRIAL WASTE STREAMS

Paper number: T133-10
Program: Technical Sessions
Time: 3:40 PM – 4:00 PM

Authors

Dante Simonetti Presenting Author
University of California Los Angeles, Los Angeles, CA
Steven Bustillos
University of California Los Angeles, Los Angeles, CA
Marios Christofides
University of California Los Angeles, Los Angeles, CA
Gaurav Sant
University of California Los Angeles, Los Angeles, CA
Bonnie McDevitt
Geology, Energy & Minerals Science Center, Reston, VA
Madalyn Blondes
U.S. Geological Survey, Reston, VA
Ryan McAleer
US Geological Survey, Reston, VA
Aaron Jubb
U.S. Geological Survey, Reston, VA

Abstract

The sequestration of CO₂ within stable mineral carbonates (e.g., CaCO₃) represents an attractive emissions reduction strategy because it offers an energy efficient, environmentally benign, and leakage-free alternative to geological storage. However, continuous addition of alkalinity is required to achieve favorable conditions for carbonate precipitation (pH>8) from aqueous streams containing dissolved CO₂ (pH<4.5) and Ca²⁺ ions (such as produced water). Herein, a pH-swing process using re-generable ion exchange media is described as a means to capture CO₂ from industrial process streams (5-50% v/v CO₂) using produced water streams rich in Ca²⁺ ions. In this process, the ion exchange media induces alkalinity in CO₂-containing aqueous streams to achieve the pH required for mineralization of CO₂ with Ca²⁺ ions (to form CaCO₃), thereby avoiding the need for expensive stoichiometric reagents such as caustic soda (e.g., NaOH). Nanofiltration and reverse osmosis steps recover Mg²⁺ and Na⁺ rich streams; the latter of which is used to regenerate the ion exchange media to complete the pH-swing cycle.

A combination of experimental ion-exchange studies with geochemical and process-modeling was used to identify the thermodynamic conditions that maximize CO₂ removal potential while minimizing energy intensity. Energy consumption was minimized under conditions where CaCO₃ yields were maximized across a variety of produced water compositions and CO₂ concentrations. The energy intensity of the process (0.22−2.10 MW·h/t of CO₂ removed) was dependent on the concentration of CO₂ in the gas phase (i.e., 5−50 vol %) and the produced water composition, with the nanofiltration and reverse osmosis steps used to recover magnesium requiring the most energy (0.07−0.80 MW·h/t of CO₂ removed). Life cycle assessments were performed to analyze the net carbon emissions of the technology which indicated a net CO₂ reduction of 0.06 to 0.39 kg CO_2e per kg precipitated CaCO₃ utilizing calcium-rich brines and gaseous streams with pCO≥0 .12 atm. The results from this study indicate the ion exchange process can be used as a scalable method to provide alkalinity necessary for the capture and storage of CO2 in Ca-rich waste streams.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-401606

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