Long-term Carbonate Looping Testing in a 1 MWth Pilot Plant with Hard Coal and Lignite

Simulation and Optimization of a Multistage Interconnected Fluidized Bed Reactor for Coal Chemical Looping Combustion

This work established a three-dimensional model of a chemical looping system with multistage reactors coupled with hydrodynamics and chemical reactions. The thermal characteristics in the chemical looping combustion (CLC) system were simulated using coal as fuel and hematite as an oxygen carrier (OC). Some significant aspects, including gas composition, particle residence time, backmixing rate, wall erosion, carbon capture rate, etc., were investigated in the simulation. Owing to the optimization by adding baffles in the fuel reactor (FR), the gas conversion capacity of the multistage FR was high, where the outlet CO₂ concentration was as high as 93.8% and the oxygen demand was as low as 3.8%. Through tracing and analyzing the path of char particles, we found that the residence time of most char particles was too short to be fully gasified. The residual char will be entrained into the air reactor (AR), reducing the CO₂ capture rate, which is only 80.3%. In the simulation, the wall erosion on the cyclone could be relieved by increasing the height of the horizontal pipe. In addition, improving the structure of the AR loop seal could control the residual char entrained by OC particles to the AR, and the CO₂ capture rate was increased up to 90% in the multistage CLC reactor.

CO2 Capture at Medium to High Temperature Using Solid Oxide-Based Sorbents: Fundamental Aspects, Mechanistic Insights, and Recent Advances

Carbon dioxide capture and mitigation form a key part of the technological response to combat climate change and reduce CO₂ emissions. Solid materials capable of reversibly absorbing CO₂ have been the focus of intense research for the past two decades, with promising stability and low energy costs to implement and operate compared to the more widely used liquid amines. In this review, we explore the fundamental aspects underpinning solid CO₂ sorbents based on alkali and alkaline earth metal oxides operating at medium to high temperature: how their structure, chemical composition, and morphology impact their performance and long-term use. Various optimization strategies are outlined to improve upon the most promising materials, and we combine recent advances across disparate scientific disciplines, including materials discovery, synthesis, and in situ characterization, to present a coherent understanding of the mechanisms of CO₂ absorption both at surfaces and within solid materials.