Assessment of the Impact of Modification of Calcium Sorbents and the Possibility of Their Use in Desulfurization for Oxy-Fuel Combustion Process

Abstract

The paper describes the possibilities of simple and effective modification of calcium sorbents used for flue gas desulfurization with a size between of 125–250 µm. The additives to the sorbents in the amount of 0.5% and 1.0% were inorganic sodium and lithium compounds. The research on the reactivity of sorbents was analyzed in the process of simultaneous calcination and sulfation at the temperature of 850 °C. The type of Na+ or Li+ cations and the inorganic salt anions have an influence on the modification of calcium sorbents in order to improve the efficiency of the calcination and sulfation process. Modification of calcium sorbents by adding inorganic sodium and lithium compounds, regardless of the amount, changes the reactivity coefficient RI [mol/mol] and the absolute sorption coefficient CI [g S/kg sorbent]. In the case of inorganic sodium salt (Additive 1), regardless of the amount of modifier added, there was a visible improvement in the reactivity of the sorbent: 1.0% of the additive caused an increase in the RI coefficient in relation to the raw sorbent by over 14%, and in the case of the CI coefficient by over 24%. Additional research was the analysis of the limestone behavior mechanism during the simultaneous calcination and sulfation (SCS) process under conditions of elevated temperature and with variable CO2 and O2 contents in the flue gas. The behavior of sorbents with a size distribution of 125–250 µm was assessed on the basis of the change in mass of the samples by determining the reactivity coefficient RI, [mol/mol] and the absolute sorption coefficient CI, [g S/kg sorbent]. Using the mercury porosimetry technique, the change in sorbent porosity in the subsequent stages of the simultaneous calcination and sulfation process was investigated. The process was carried out in the temperature range corresponding to the oxy-combustion (i.e., from 850 °C to 1000 °C).

Towards Data-Driven NARX ANN Simulation For Optimal Control Of The Flue Gas Desulphurization For Coal Power Plants

“…The reactivity of the calcium-based sorbent is variable. The process, as an exothermic reaction, depends on changes in temperature, humidity, and the contact time of the sorbent with SO X [9]. Modeling the desulfurization process can be useful in predicting and assessing the impact of parameter changes on its efficiency, diagnosing problems, and, of course, predicting emissions under changing conditions.…”

Influence of Compound Additives on Sulfur Fixing Performance of Sorbent Based on Steel Slag at High Temperatures

“…Commonly used sulfur fixing agents [4,5] are CaCO 3 [6,7], Ca(OH) 2 and CaO [8], and non-calcium-based sulfur fixing agents have limited application in coal combustion sulfur fixing due to high prices. Calcium-containing solid waste, such as calcium carbide slag, red mud [9], white mud, fly ash, steel slag, etc.…”