Selective sulfur removal from semi-dry flue gas desulfurization coal fly ash for concrete and carbon dioxide capture applications
| Autor: | Raghavendra Ragipani, Steven Bustillos, Eleanor Escobar, Dale P. Prentice, Gaurav Sant, Bu Wang, Dante A. Simonetti |
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| Rok vydání: | 2020 |
| Předmět: |
Flue gas
020209 energy chemistry.chemical_element 02 engineering and technology 010501 environmental sciences 01 natural sciences Coal Ash chemistry.chemical_compound 0202 electrical engineering electronic engineering information engineering Sulfur Dioxide Waste Management and Disposal Dissolution 0105 earth and related environmental sciences Carbonic acid Chemistry fungi Carbon Dioxide Pulp and paper industry Sulfur Flue-gas desulfurization Coal Calcium sulfite Fly ash Carbon dioxide Power Plants |
| Zdroj: | Waste management (New York, N.Y.). 121 |
| ISSN: | 1879-2456 |
| Popis: | High-sulfur mixed fly ash residues from semi-dry flue gas desulfurization units in coal-fired power plants are unsuitable for use as supplementary cementitious material (SCM) for concrete production or carbon dioxide utilization. In this work, we explore the potential for upcycling a representative spray dry absorber ash (10.44 wt% SO3) into concrete-SCM by selective sulfur removal via weak acid dissolution while simultaneously exploring the possibility for CO2 capture. Towards this effort, parametric studies varying liquid-to-solid ratio, acidity, and CO2 pressure were conducted in a batch reactor to establish the sulfur removal characteristics in de-ionized water, nitric acid, and carbonic acid, respectively. The dissolution studies show that the leaching of sulfur from calcium sulfite hemihydrate, which is the predominant S phase, is rapid and achieves a concentration plateau within 5 min, and subsequently, appears to be controlled by the primary mineral solubility. Preferential S removal was sufficient to meet SCM standards (e.g., 5.0 wt% as per ASTM C618) using all three washing solutions with 0.62–0.72 selectivity ( S ^ ), defined as the molar ratio of S to Ca in the leachate, for a raw fly ash with bulk S ^ = 0.3. Acid dissolution with 1.43 meq/g of ash or under 5 atm CO2 retained > 18 wt% CaO and other Si-, Al-rich phases in the fly ash. Based on the experimental findings, two sulfur removal schemes were suggested for either integration with CO2 capture and utilization processes using flue gas or to produce fly ash for use as a SCM. |
| Databáze: | OpenAIRE |
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