Performance Evaluation of Functionalized Biocarbon for Mercury Capture

Abstract

In this study, functionalized biocarbon (FBC) as a sorbent to capture mercury (Hg) from flue gas was developed and tested. The sorbent before and after Hg capture was characterized. The developed sorbent was tested for elemental Hg (Hg0) capture efficiency in a (i) Hg pulse injection test, in an argon atmosphere, (ii) simulated flue gas of (a) 350 ppm of SO2, 5% O2, and balanced with N2 or (b) 300 ppm of NO2, 5% O2, and balanced with N2, and (iii) coupon test in a commercially operating coal-fired power plant. Hg0 capture by FBC in Hg pulse injection tests, simulated flue gas with NO2 and SO2, and flue gas from a coal-fired power plant were very promising and comparable to a commercial sorbent. An average Hg capture efficiency of >96% by FBC was noted in all of the experiments. The Hg concentration in the leachate solutions was negligible and below the regulated toxicity limits by a significant factor. Urea-activated biocarbon, used in this study, showed technical parameters comparable to commercial activated carbons (ACs) (high surface area of 500–800 m2/g and high nitrogen content of 4 wt %, on a dry basis) and captured the same amount of mercury with a lower cost, which proved the robustness of FBC. The developed FBCs can be employed to capture Hg, where ACs are currently in demand and would offer a cheap alternate replacement with similar capture efficiency.

Influence of Different Sulfur Forms on Gas-Phase Mercury Removal by SO2-Impregnated Porous Carbons

“…To date, activated carbon injection technology is considered as a promising mercury control technology for coal-fired power plants with the advantage of guaranteed high performance in vapor phase mercury removal and many attempts have been made to make it more commercial acceptable by lowering down the operating cost in recent years, including sorbent modification with halogen − and sulfur , to improve the mercury uptake capacity of sorbents or replacing costly commercial activated carbon with other low-cost sorbents prepared from waste materials, such as biomass and petroleum coke . Emphasis is also given to prepare the surface-modified adsorbents using different procedures, such as solution impregnation, , heat treatment, , plasma treatment, , and microwave treatment, to enhance the potential for mercury adsorption.…”

Interference Effect of Experimental Parameters on the Mercury Removal Mechanism of Biomass Char under an Oxy-Fuel Atmosphere

“… 29 , 30 Biomass char is an ideal adsorbent for mercury removal due to its low price, abundant surface functional groups, simple raw materials, and environmental protection. 31 , 32 …”

“…29,30 Biomass char is an ideal adsorbent for mercury removal due to its low price, abundant surface functional groups, simple raw materials, and environmental protection. 31,32 The parameters in the experiment will also have a great impact on the experimental results. Zhao et al 33 showed that the change of Hg 0 removal efficiency with the increase of reaction temperature is non-monotonical.…”

“…At present, activated carbon injection (ACI) is the most mature and feasible technology for mercury removal in coal-fired power plants. , Scholars have carried out a lot of experiments and theoretical studies on mercury removal by activated carbon from coal-fired flue gas. − However, activated carbon is expensive and not suitable for large-scale commercial use. Nowadays, researchers have turned their attention to biomass. , Biomass char is an ideal adsorbent for mercury removal due to its low price, abundant surface functional groups, simple raw materials, and environmental protection. , …”