Ca(OH)₂‐Based Calcium Looping Process Development at The Ohio State University

Abstract

The cyclic calcium oxide‐calcium carbonate (CaO‐CaCO3) process is a promising option for large‐scale CO2 control. Important advantages include high‐temperature operation, inexpensive sorbent feedstock, and high CO2 capture capacity of CaO. However, decreasing sorbent reactivity over multiple cycles, due to high‐temperature sintering, presents a major challenge for further progress. The Ohio State University (OSU) has led the development of a novel three‐step calcium looping (CaO‐Ca(OH)2‐CaCO3) process for post‐ and precombustion CO2 capture. An overview of OSU's work is provided, highlighting the differences in this approach when compared to competing efforts in this field.

Effects of Steam Addition during Calcination on Carbonation Behavior in a Calcination/Carbonation Loop

“…The carbonation conversion of CaO after 20 cycles increased from 16.0 to 23.4 % and then to 25.5 % for calcinations in N 2 streams of 30 and 80 % relative humidity, respectively. The current study assumed that steam does not react with CaO to form Ca(OH) 2 during calcination because of hydration thermodynamic properties of CaO at the calcination temperature of 850 °C .…”

High‐Temperature Capture of CO2 on Lithium‐Based Sorbents Prepared by a Water‐Based Sol‐Gel Technique

“…The increasing concentration of CO 2 in the atmosphere, mostly resulting from fossil fuel burning, has been identified as a major contributor to global warming 1, 2. Because of higher efficiency and economics in power plants 3, high‐temperature (above 450 °C) adsorbent materials for CO 2 capture such as hydrotalcites (HTL) 4, 5, calcium oxides 6–9, and lithium ceramics 5, 10, 11, have been tested for their utility in the CO 2 capture process. Among them, lithium ceramics, especially lithium zirconate (Li 2 ZrO 3 ) and lithium orthosilicate (Li 4 SiO 4 ), have been proposed as attractive adsorbents.…”

New insights into the mechanisms of carbon dioxide mineralization by portlandite

“…At one end, the carbonation of conventional portland cement concrete is a deleterious process that occurs over years as concrete interacts with atmospheric CO 2 43 . In other cases, the carbonation of lime/hydrated lime particulates has been examined in the context of cyclic carbon capture applications, for example, calcium looping 44‐48 . This study examines a processing regime that has received far less attention—that is, subboiling temperatures, super‐ambient CO 2 concentrations, and effectively, atmospheric pressure.…”