Influence of pyrolysis conditions on the mercury removal characteristics and physicochemical properties of biomass coke

Zhao, Shilin; Luo, Hui; Ma, Anjun; Xie, Wen; Sun, Kang; Sun, Zhiqiang

doi:10.1016/j.fuel.2021.122979

Cited by 19 publications

(8 citation statements)

References 37 publications

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“…It is noted that pyrolysis parameters are raised concern for the development of optimal pore structure for Hg 0 adsorption and better chemical loading for Hg 0 oxidation, such as atmosphere, final temperature, heating, and cooling rate, holding time, and even the mesh selection for controllable pyrolysis. Zhao et al [ 41 ] reported the largest specific surface area of pyrolyzed biomass coke by pyrolysis parameters of 7% O 2 , 800 °C, and the heating rate of 10 K/min. Moreover, the micropore structure was obtained with an average pore diameter of 1.93 nm.…”

Section: The Effect Of the Evolution Of Pore Structure On Hg ...mentioning

confidence: 99%

“…Combined with the aim of optimal pore structure, pyrolysis with adjusting parameters including temperature, heating rate, atmosphere, holding time, and so on, is a hopeful activation for adding the oxygen-containing surface functional groups. Zhao et al [ 41 ] set the pyrolysis of 7% O 2 and 15% CO 2 under the pyrolysis temperature of 500−800 °C with the heating rate of 5, 10, and 15 K/min for biomass. The result of FTIR showed that the functional groups on the surface of the samples mainly exist in the form of O–H, C–O, and C–O–O–.…”

Section: The Effect Of the Evolution Of Functional Groups On Hg ...mentioning

confidence: 99%

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The Effects of Physical-Chemical Evolution of High-Sulfur Petroleum Coke on Hg0 Removal from Coal-Fired Flue Gas and Exploration of Its Micro-Scale Mechanism

Jiang

Diao

2022

IJERPH

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As the solid waste by-product from the delayed coking process, high-sulfur petroleum coke (HSPC), which is hardly used for green utilization, becomes a promising raw material for Hg0 removal from coal-fired flue gas. The effects of the physical–chemical evolution of HSPC on Hg0 removal are discussed. The improved micropores created by pyrolysis and KOH activation could lead to over 50% of Hg0 removal efficiency with the loss of inherent sulfur. Additional S-containing and Br-containing additives are usually introduced to enhance active surface functional groups for Hg0 oxidation, where the main product are HgS, HgBr, and HgBr2. The chemical–mechanical activation method can make additives well loaded on the surface for Hg0 removal. The DFT method is used to sufficiently explain the micro-scale reaction mechanism of Hg0 oxidation on the surface of revised-HSPC. ReaxFF is usually employed for the simulation of the pyrolysis of HSPC. However, the developed mesoporous structure would be a better choice for Hg0 removal in that the coupled influence of pore structure and functional groups plays a comprehensive role in both adsorption and oxidation of Hg0. Thus, the optimal porous structure should be further explored. On the other hand, both internal and surface sulfur in HSPC should be enhanced to be exposed to saving sulfur additives or obtaining higher Hg0 removal capacity. For it, controllable pyrolysis with different pyrolysis parameters and the chemical–mechanical activation method is recommended to both improve pore structure and increase functional groups for Hg0 removal. For simulation methods, ReaxFF and DFT theory are expected to explain the micro-scale mechanisms of controllable pyrolysis, the chemical–mechanical activation of HSPC, and further Hg0 removal. This review work aims to provide both experimental and simulational guidance to promote the development of industrial application of Hg0 adsorbent based on HSPC.

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Section: The Effect Of the Evolution Of Pore Structure On Hg ...mentioning

confidence: 99%

Section: The Effect Of the Evolution Of Functional Groups On Hg ...mentioning

confidence: 99%

The Effects of Physical-Chemical Evolution of High-Sulfur Petroleum Coke on Hg0 Removal from Coal-Fired Flue Gas and Exploration of Its Micro-Scale Mechanism

Jiang

Diao

2022

IJERPH

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“…Coal-fired power plants are one of the main sources of mercury emissions. − As a highly toxic heavy-metal element, mercury has the characteristics of persistence, bioaccumulation, and long-distance migration, which poses a huge threat to human health and the ecological environment. , As of 2016, 128 countries and regions have signed the Minamata Convention aimed at protecting human health and the environment from mercury and its mercury compounds . Mercury in coal combustion flue gas is mainly composed of elemental mercury (Hg 0 ), divalent mercury (Hg 2+ ), and particulate mercury (Hg P ). − Since elemental mercury is insoluble in water, the capture of elemental mercury is a key link in the removal of mercury from flue gas. , …”

Section: Introductionmentioning

confidence: 99%

Elemental Mercury Removal from Coal-Fired Flue Gas on Sulfur-Modified Activated Biomass Coke: Experiment and Simulation

Zeng

Wang

Kang

et al. 2023

Ind. Eng. Chem. Res.

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It is necessary to find a better method to remove mercury from coal-fired flue gas. This work proposes the use of corn stalk coke to remove mercury from coal-fired flue gas and through elemental sulfur (CSC-S), water vapor activation (CSC-H 2 O), and sulfur modification combined with water vapor activation (CSC-H 2 O-S) to prepare three different adsorbents. The mercury removal performance of the adsorbents prepared by different methods was evaluated on a small fixed-bed mercury removal experimental platform. The experimental results showed that the order of mercury removal efficiency of the four adsorbents was: CSC-H 2 O-S > CSC-S > CSC-H 2 O > CSC. Brunauer−Emmett−Teller (BET), Fourier transform infrared (FTIR) spectroscopy, and Xray photoelectron spectroscopy (XPS) were adopted to study the physical and chemical properties of the adsorbent surface and the mechanism of mercury removal. The results showed that water vapor activation can improve the pore structure of the adsorbent, increase its specific surface area, and generate new oxygen-containing functional groups on the surface of the adsorbent. The adsorption kinetic model further demonstrated that the water vapor activation process can improve the physical adsorption performance of corn stalk char, and the sulfur modification process can improve the chemical adsorption performance of corn stalk char. Quantum chemical studies have shown that the surface structure doped with S and O atoms is conducive to enhancing the adsorption of Hg 0 .

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“…14,15 Hg 0 is particularly challenging to remove due to its volatility and insolubility in water. 16,17 Currently, activated carbon is widely used as an adsorbent for mercury removal. 18,19 Nevertheless, the high cost of activated carbon prompts the exploration of alternative materials such as biomass, which is inexpensive and exhibits similar properties.…”

Section: Introductionmentioning

confidence: 99%

Multiscale Understanding of the Mechanism of Mercury Removal by Acid–Chlorine-Modified Biomass Coke: Experiments and Simulations

Le,

Wang,

Zeng

et al. 2023

Energy Fuels

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Coal-fired power plants are a significant source of mercury pollution, necessitating the development of inexpensive and efficient adsorbents for mercury removal. This work proposes the preparation of an adsorbent using acid-chlorine-modified rice straw coke for this purpose. The characterization of the adsorbent shows that the modification increases the surface pore structure and makes the surface carry abundant oxygen-containing functional groups, which is conducive to improving the mercury removal capacity of the adsorbent. This work studies the effects of the acid–chlorine ratio, mass ratio, inlet mercury concentration, and reaction temperature on the desorption performance of modified rice straw coke and investigates the mechanism of mercury removal by combining the kinetic model and density functional theory. The results demonstrate that the optimal effect of the combined acid–chlorine modification is achieved at an acid–chlorine ratio and mass ratio of 1:2. The reaction temperature has a significant effect on the efficiency of mercury removal, and the increase of the inlet mercury concentration can promote mercury removal. The mercury adsorption process is primarily controlled by surface mass transfer and chemisorption, with chemisorption being the critical control step. The introduction of Cl and O atoms through modification creates doped structures that are highly conducive to mercury adsorption. The Cl atom exhibits greater reactivity toward the Hg atom, facilitating the removal of mercury. The presence of O atoms not only increases the abundance of oxygen-containing functional groups on the surface, but also enhances the activity of the Cl atoms. These findings provide valuable theoretical support for the application of biomass coke in the field of mercury removal, addressing mercury pollution associated with coal-fired power plants.

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Influence of pyrolysis conditions on the mercury removal characteristics and physicochemical properties of biomass coke

Cited by 19 publications

References 37 publications

The Effects of Physical-Chemical Evolution of High-Sulfur Petroleum Coke on Hg0 Removal from Coal-Fired Flue Gas and Exploration of Its Micro-Scale Mechanism

The Effects of Physical-Chemical Evolution of High-Sulfur Petroleum Coke on Hg0 Removal from Coal-Fired Flue Gas and Exploration of Its Micro-Scale Mechanism

Elemental Mercury Removal from Coal-Fired Flue Gas on Sulfur-Modified Activated Biomass Coke: Experiment and Simulation

Multiscale Understanding of the Mechanism of Mercury Removal by Acid–Chlorine-Modified Biomass Coke: Experiments and Simulations

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