Release behavior of mercury during mild pyrolysis of coals and nitric acid-treated coals

Ohki, Akira; Sagayama, Kota; Tanamachi, Shomei; Iwashita, Akira; Nakajima, Tsunenori; Takanashi, Hirokazu

doi:10.1016/j.powtec.2007.03.004

Cited by 24 publications

(16 citation statements)

References 7 publications

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“…It indicates that the carbonate-bound mercury releases at the temperature range of 250−300 °C, which is analogous to the results of carbonate-bound mercury release temperature range of coal reported in literature. 28 This verifyies that carbonatebound mercury can be removed through mild pyrolysis below 300 °C.…”

Section: Energy and Fuelsmentioning

confidence: 65%

Evaluation of Mercury Removal Efficiency of Coal through Solvent Extraction Procedures

et al. 2019

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Mild pyrolysis is one of the precombustion mercury control techniques. Mercury removal efficiency through mild pyrolysis has close relation with the weak thermal stability of mercury in coal. The thermal stability mercury in coal has been identified by solvent extraction procedures combined with temperature-programmed decomposition techniques. The result shows that the carbonate-bound mercury, iron−manganese oxide-bound mercury, organic-bound mercury, and sulfidebound mercury should be classified into the weak thermal stability mercury and can be removed by mild pyrolysis. Therefore, a method can be established to evaluate the mercury removal ability by determining the carbonate-bound mercury, iron− manganese oxide-bound mercury, organic-bound mercury, and sulfide-bound mercury through solvent extraction procedures. This result of this method is in good agreement with the result of heat treatment experiment, indicating that this method is an effective approach to evaluate the mercury removal efficiency through mild pyrolysis.

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Section: Energy and Fuelsmentioning

confidence: 65%

Evaluation of Mercury Removal Efficiency of Coal through Solvent Extraction Procedures

et al. 2019

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“… 24 , 25 Depending on the extraction process, it is difficult to reach an agreement on the classification results, and even the original Hg species might be changed due to the use of some leachates, such as strong oxidant acids. 26 , 27 The TPD method distinguishes the Hg types based on the unique thermal stability characteristics of different Hg species. This method has advantages of no chemical treatment, easy operation, and intuitive visualization.…”

Section: Methodsmentioning

confidence: 99%

Study on Mercury Species in Coal and Pyrolysis-Based Mercury Removal before Utilization

et al. 2020

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Coal-fired mercury (Hg) pollution control is an important global environmental context. Eight coal samples from different coal fields in China were used to investigate Hg species and the Hg removal effects under different pyrolysis conditions in the presence of nitrogen. These conditions included temperature, particle size, and residence time. The study concludes that the temperature is the most important factor affecting Hg removal from coal, and the mercury release activity at specific temperatures depends on the species and content of Hg present. Large particle size limits the removal rate of Hg, and coal particles smaller than 40 mesh are more favorable for the rapid removal of Hg. For most coal types, pyrolysis of 10–15 min can achieve the ultimate Hg removal effect. Rapid pyrolysis at 600 °C in nitrogen is feasible to remove Hg from coal. Consequently, the Hg removal rate reaches 88–100%, the loss rate of coal calorific value is 2–12%, and approximately 17–58% of S is removed synergistically. HgS, HgSe, HgSO 4 , organic matter Hg, and HgO are the main types of Hg species detected in coal, whose thermal decomposition characteristics are the essential criteria for determining the type of Hg removal process. This research will facilitate the improvement of pollution control methods for coal-source Hg pollution.

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“…This process involves heating the coal to a temperature of 200–400 °C. In this process, both organic-bound mercury as well as mercury occurring in mineral matter (in chlorides, oxides, carbonates, and aluminosilicates) can be removed. − However, it is worth mentioning that it is difficult to remove mercury occurring in pyrite as well as in other sulfides in this process . It should be noted that the thermal pretreatment of hard coal leads to changes in its structure. − These result in an insignificant loss of energy contained in coal .…”

Section: Introductionmentioning

confidence: 99%

Valorization Method for Hard Coal as Fuel for Nonindustrial Combustion Installations with Special Regard to Reduction of Mercury Content

et al. 2020

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Mercury and its compounds are classified as very toxic and they pose a real threat to human health. Coal combustion processes constitute one of the main sources of mercury emission to the environment. The use of hard coal by the nonindustrial combustion installations sector (among others households) is a special issue. In contrast to large coal-fired power plants, such users are not equipped with systems for reducing emissions. For this group of users, it is necessary to use hard coal with the lowest possible mercury content. In the paper, a method for the production of hard coal with low mercury content based on combined processes of dry deshaling and thermal pretreatment is proposed. The proposed method allowed for a reduction of mercury content in the analyzed coals from 43 to even 92% (in relation to its lower heating value). The produced coals were characterized by relatively low mercury contents from 1.5 to 4.8 μg/MJ with an average of 2.4 μg/MJ. The application of this method may potentially reduce the annual mercury emission from the Polish sector of nonindustrial combustion installations by 0.365 Mg.

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Release behavior of mercury during mild pyrolysis of coals and nitric acid-treated coals

Cited by 24 publications

References 7 publications

Evaluation of Mercury Removal Efficiency of Coal through Solvent Extraction Procedures

Evaluation of Mercury Removal Efficiency of Coal through Solvent Extraction Procedures

Study on Mercury Species in Coal and Pyrolysis-Based Mercury Removal before Utilization

Valorization Method for Hard Coal as Fuel for Nonindustrial Combustion Installations with Special Regard to Reduction of Mercury Content

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