Sustainable Use of Natural Geological Materials and Marble Wastes as Promising Calcium Looping Sorbents for CO2 Capture in the Cement Industry: Comparative Study
8 Pages Posted: 12 Feb 2019 Last revised: 13 Apr 2021
Date Written: September 11, 2018
The present work focuses on the comparative study of the Calcium looping CO2 capture capacity and stability along 10 or 20 calcination-carbonation cycles, of three different marble powder wastes (MW) and two calcite samples (one from West Bank and another provided by CIMPOR) using a gas mixture with a /sub>CO2 concentration of 25% to mimic the real flue gases CO2 concentration in the cement industry.
Very high initial carbonation (first cycle) conversions were obtained using the MW sorbents tested, which is a very interesting and promising result when compared with the initial carbonation conversions of the natural calcite sorbent currently used in industry as raw material for the cement production. For the Calcium-looping conditions used, the MW sorbent tested on the fixed bed reactor unit exhibits better cyclic stability with a lower sorbent deactivation with the number of cycles than the natural calcite resource used for the cement production.
The presence of 5% of steam in the feed gas mixture with air atmosphere leads to significant differences on the sorbents cyclic performance when comparing with the results obtained for the standard calcination conditions. For both MW and calcite sorbent samples selected and tested on the fixed bed rector unit in the presence of steam, a lower CaO carbonation conversion is observed along the first 7 cycles, but a higher cyclic stability reaching a CaO conversion plateau, with a lower deactivation after 20 cycles, when comparing with the results for the standard calcination conditions.
An improved sorbent stability for Ca-looping CO2 capture was observed during the carbonation-calcination cycles in the presence of steam which could allow reducing the make-up of CaO frequency along the time and the costs associated.
The selection of suitable marble wastes as CaO-based sorbents, the improvement of their performance and the incorporation of exhausted sorbents in the clinker, can contribute to reducing the CO2 footprint of cement production and avoid the production of wastes associated to the marble producers.
Keywords: Capture, Sustainable, CO2, Cement, Study, GHGT-14
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