Review of arsenic behavior during coal combustion: Volatilization, transformation, emission and removal technologies

Abstract

Growing public awareness of the environmental impact of coal combustion has raised serious concerns about the various hazardous trace elements produced by coal firing. Arsenic deserves special attention due to its toxicity, volatility, bioaccumulation in the environment, and potential carcinogenic properties. As the main anthropogenic source of arsenic is coal combustion, its behavior in power plants is of concern. Unlike mercury, arsenic behavior in coal combustion has not been subjected to systematic, in-depth research. Different researchers have reached opposing conclusions about the behavior of arsenic in combustion systems and as yet there is relatively little research on arsenic-removal technologies. In this paper, the volatilization, transformation, and emission behavior of arsenic and its removal technologies are discussed in depth. Factors affecting the volatilization characteristics of arsenic are summarized, including temperature, pressure, mode of occurrence of arsenic, coal rank, mineral matter, and the sulfur and chlorine content of the fuel. The behavior of arsenic during oxy-fuel combustion and the effect of combustion atmosphere (O2, CO2, SO2 and H2O(g)) are also reviewed in detail. In order to better understand the pathway of arsenic in a power plant environment, a particular focus in this work is the transformation mechanism of ultra-fine ash particles and the partitioning behavior of arsenic. Finally, the effects of air pollution control devices (APCDs) on arsenic emissions are examined, along with the

Mineralogy and geochemistry of feed coals and combustion residues of the Kangal power plant (Sivas, Turkey)

“…The abundance of Ca-bearing sulfate and lime in the studied FA samples could cause this difference. Furthermore, CaO and Ca-sulfates in the FA have a tendency to retain As, Mo, Cd, Tl, and U (Hower et al, 2009;López-Antón et al, 2013;Silva et al, 2014;Zhang et al, 2016;Wang et al, 2018). Therefore, the Group I elements were enriched in the studied FA samples.…”

Simultaneous removal of SO2 and NOx by a new combined spray-and-scattered-bubble technology based on preozonation: From lab scale to pilot scale

“…Coal-fired power generation accounts for more than 40% of global electricity supply and is expected to continue to play a key role in the energy sector [1]. However, due to the massive use of coal in power generation, coal-fired units are the main anthropogenic source of SO 2 and NOx [2].…”

Effect of H2O on the volatilization characteristics of arsenic during isothermal O2/CO2 combustion

“…The volatilization and partitioning behavior of As is influenced by several factors, including the combustion temperature and combustion atmosphere [7][8][9][10][11]. In O 2 /CO 2 combustion, the CO 2 concentration in the furnace can reach 60%~80% or more [12][13][14][15], which is significantly higher than that in air fired combustion.…”

“…Given its nature as a semi-volatile toxic metal, most of the arsenic (As) in coal will volatilize during combustion and be found in fly ash, bottom ash and the gas phase as the flue gas cools down, and some of it will finally be emitted into the atmosphere [4,5]. The release of As is attracting increasing attention because it not only affects several human organs, but also interferes with the immune system [6].The volatilization and partitioning behavior of As is influenced by several factors, including the combustion temperature and combustion atmosphere [7][8][9][10][11]. In O 2 /CO 2 combustion, the CO 2 concentration in the furnace can reach 60%~80% or more [12][13][14][15], which is significantly higher than that in air fired combustion.…”