Effects of NH<sub>4</sub>Br additive on mercury transformation and removal during CFB coal combustion

Zhao, Shilin; Duan, Yufeng; Zhou, Qiang; Zhu, Chun; Liu, Meng; Lu, Jincheng

doi:10.1002/jctb.5017

Cited by 18 publications

(15 citation statements)

References 44 publications

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“…For Br 3d, a peak at around 67.8 eV was attributed to surface-bound HBr compounds and another peak at around 70.1 eV belonged to covalent Br (C–Br). ,, In comparison to the data from raw RHCBr0.5, it could be inferred that Br – turned into HBr after being exposed to the simulated oxy-fuel atmosphere with HCl. Zhao et al and Yang et al also found a similar phenomenon.…”

Section: Results and Discussionmentioning

confidence: 55%

NH₄Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

et al. 2020

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Mercury from recycled oxy-fuel gas needs to be removed because it can damage the aluminum devices in the system. In this work, low-cost NH4Br-modified rice husk char (RHCBr) was prepared as the biosorbent for mercury removal in an oxy-fuel atmosphere. RHCBr was characterized by scanning electron microscopy, Brunauer–Emmett–Teller, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) technologies to study the physical and chemical properties of the prepared sorbents. Effects of O2, HCl, SO2, and HCl/SO2 synthesis on mercury removal in a simulated oxy-fuel atmosphere were investigated in a fixed-bed reactor. XPS technology was applied to explore the mercury adsorption species and deduce the potential mercury heterogeneous oxidation mechanism in an oxy-fuel atmosphere. It was found that enriched CO2 in an oxy-fuel atmosphere could facilitate the mercury removal process. Generally, O2 and HCl could promote the mercury removal efficiency in an oxy-fuel atmosphere, while SO2 could inhibit it. However, a low concentration of SO2 could promote it with the presence of HCl and O2. The mercury adsorption species on RHCBr were mainly HgSO4, HgCl2, and HgBr2 in the presence of acid gas components (HCl and SO2). HCl could actively facilitate the generation of C–Cl groups, which were also active sites for mercury removal, while SO2 could generate active site cover NH4HSO4, causing the deactivation of active sites. When HCl/SO2 synthesis was added, active site cover HSO4 – would be removed by HCl, facilitating the mercury removal process. Meantime, HgCl2 species could be further converted to the strong-bonded species HgSO4 in the presence of O2 and SO2, which was also beneficial for mercury removal.

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Section: Results and Discussionmentioning

confidence: 55%

NH₄Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

et al. 2020

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“…The proximate and ultimate analysis of the feeding coal was shown in Table . The mercury content in this type of coal is 62.84 ng/g, which is less than the mean value of coal in China (200 ng/g) . Besides, the chlorine content, which is regarded as the most important component influencing mercury oxidation, is 0.05% attributed to the low Cl content of coal .…”

Section: Experimental Methodologymentioning

confidence: 67%

“…The mercury content in this type of coal is 62.84 ng/g, which is less than the mean value of coal in China (200 ng/g). 25 Besides, the chlorine content, which is regarded as the most important component influencing mercury oxidation, is 0.05% attributed to the low Cl content of coal. 26 On the basis of the national coal classification standard of China (GB/T 5751-2009), the feeding coal is bituminous.…”

Section: Introductionmentioning

confidence: 99%

Influence of Flue Gas Conditions on Mercury Removal by Activated Carbon Injection in a Pilot-Scale Circulating Fluidized Bed Combustion System

Huang

Duan

Luo

et al. 2019

Ind. Eng. Chem. Res.

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The synergistic removal of mercury by injecting activated carbon between the selective catalytic reduction (SCR) and fabric filter (FF) as well as some influencing factors were investigated in a pilot-scale 0.3 MWth circulating fluidized bed (CFB) combustion system. The Ontario Hydro Method (OHM) was used to sample mercury in the coal-fired flue gas. The gaseous elemental mercury (Hg 0 ), gaseous oxidized mercury (Hg 2+ ), particle-bound mercury (Hg p ) in the flue gas after the boiler, SCR, activated carbon injection (ACI) device, FF, and wet flue gas desulfurization (WFGD) were sampled simultaneously, and the flue gas components were monitored online. The results showed that the mercury removal efficiency of the SCR+ACI+FF system (SAFs) and the proportion of Hg P after ACI increased with the increase of the flue gas temperature. The mercury removal efficiency decreased with incremental SO 2 concentration probably due to its suppressive effect on the combination of mercury and halogen and its competitive adsorption with mercury. The higher NO concentration can improve the mercury removal efficiency resulting from Hg 0 oxidation by NO 2 , which could counteract its adverse effect on mercury oxidation in SCR. The FF device not only could capture all Hg P but also had a considerable effect on gaseous mercury. The synergistic mercury removal efficiency of the ACI and air pollution control devices (APCDs) system was more than 97.4%. The presented work could provide useful information and guidance for the optimization of the operational parameters of the ACI+APCDs mercury removal technology.

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“…The thermodynamic studies also indicated that the process was spontaneous, feasible, and endothermic. Several other recent and relevant studies reported on mercury adsorption using different adsorbents are discussed …”

Section: Purification Of Mercury‐containing Wastewater Using Low‐costmentioning

confidence: 99%

Trapping Ionic Mercury Using Different Adsorbents

Ojedokun

Oluwole

Bello

2019

CLEAN Soil Air Water

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Of recent, adsorption process has gained a lot of attention as a cheap and effective means of removing trace metals from wastewater prior to discharge into water bodies. Being flexible in design and operation, the process has enabled an optimal recovery of trace metals such that the treated effluents meet the desired standards for waste disposal. Mercury is a toxicant released into the environment from natural and anthropogenic sources. It is notorious for having an unusual tendency to bio‐accumulate and persist in the food chain. Presence of mercury in food, especially those of aquatic sources has drastic implications on human health. Therefore, efforts have been made to develop and optimize low‐cost activated carbon (AC) as adsorbents for scavenging mercury from aqueous effluents. Herein, how mercury accumulates across the food chain, its health implications, and the recent advancement in the use of low‐cost ACs as adsorbent for trapping mercury from wastewater are highlighted. Relationship between the mercury removal efficiency and the surface morphology of the adsorbents as well as the influence of prevailing experimental condition on the sorption process were addressed. Challenges and future prospects of the use of low‐cost adsorbents in addressing mercury pollution in the environment are discussed.

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Effects of NH₄Br additive on mercury transformation and removal during CFB coal combustion

Cited by 18 publications

References 44 publications

NH₄Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

NH₄Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

Influence of Flue Gas Conditions on Mercury Removal by Activated Carbon Injection in a Pilot-Scale Circulating Fluidized Bed Combustion System

Trapping Ionic Mercury Using Different Adsorbents

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Effects of NH4Br additive on mercury transformation and removal during CFB coal combustion

Cited by 18 publications

References 44 publications

NH4Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

NH4Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

Influence of Flue Gas Conditions on Mercury Removal by Activated Carbon Injection in a Pilot-Scale Circulating Fluidized Bed Combustion System

Trapping Ionic Mercury Using Different Adsorbents

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Product

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Effects of NH₄Br additive on mercury transformation and removal during CFB coal combustion

NH₄Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

NH₄Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy