Emission Characteristics of Heavy Metals and Their Behavior During Coking Processes

Abstract

Besides organic pollutants, coke production generates emissions of toxic heavy metals. However, intensive studies on heavy metal emissions from the coking industry are still very scarce. The current work focuses on assessing the emission characteristics of heavy metals and their behavior during coking. Simultaneous sampling of coal, coke, residues from air pollution control devices (APCD), effluent from coke quenching, and fly ash from different processes before and after APCD has been performed. The total heavy metal concentration in the flue gas from coke pushing (CP) was significantly higher than that from coal charging (CC) and combustion of coke oven gases (CG). Emission factors of heavy metals for CP and CC were 378.692 and 42.783 μg/kg, respectively. During coking, the heavy metals that were contained in the feedstock coal showed different partitioning patterns. For example, Cu, Zn, As, Pb, and Cr were obviously concentrated in the inlet fly ash compared to the coke; among these metals Cu, As, and Cr were concentrated in the outlet fly ash, whereas Zn and Pb were distributed equally between the outlet fly ash and APCD residue. Ni, Co, Cd, Fe, and V were partitioned equally between the inlet fly ash and the coke. Understanding the behavior of heavy metals during coking processes is helpful for the effective control of these heavy metals and the assessment of the potential impact of their emissions on the environment.

The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers

“…Coke-oven workers are a typical population generally exposed to a mixture of contaminants, such as polycyclic aromatic hydrocarbons (PAHs), which are the major pollutants released from incomplete combustion of coal (Mu et al, 2012;Passant et al, 2002). Coal also contains trace amounts of metallic elements released during carbonization.…”

“…Coal also contains trace amounts of metallic elements released during carbonization. These elements often include toxic heavy metals, especially arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and lead (Pb) (Mu et al, 2012;Passant et al, 2002). The carcinogenic potential of these heavy metals has been widely Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/envres studied in humans and experimental animals ('t Mannetje et al, 2011;Boffetta et al, 2011;Huang et al, 2004;Joseph, 2009;O'Brien et al, 2003;Oller, 2002;Verougstraete et al, 2003).…”

Investigation on thermal and trace element characteristics during co-combustion biomass with coal gangue

“…This supply is mainly attributed to the traditional biomass using for heating and cooking in rural areas of developing countries (Demirbas, 2005). However, many studies have been reported that the traditional heating and cooking processes may result in low energy efficiency and high gaseous pollutant emissions during incomplete combustion (Freeman and Cattell, 1990;Mu et al, 2012;Vuthaluru, 2004;Williams et al, 2012). Therefore, the co-combustion of biomass with coal for electricity production has received fairly intensive studies, and suggested that the thermochemical reactivity and combustion properties could be promoted by addition of suitable proportion of biomass (Gil et al, 2010;Goldfarb and Liu, 2013;Haykiri-Acma et al, 2006;Idris et al, 2012;Masnadi et al, 2014;Vamvuka et al, 2003).…”

Characteristics of Organic Carbon and Elemental Carbon in the Ambient Air of Coking Plant

“…Coking is a dry distillation process in oxygen-free conditions at high temperatures (Mastral and Callén, 2000). The contaminants emitted during coking include inorganic compounds, heavy metals, OC, and EC (Tsai et al, 2007;Mu et al, 2012;Liu et al, 2013;Mu et al, 2013;Liu et al, 2014). Coke-plant workers are exposed to organic pollutants, leading to high lung cancer mortality (Redmond, 1983;Bertrand et al, 1987).…”