Sulfur and Nitrogen Distributions during Coal Carbonization and the Influences of These Elements on Coal Fluidity and Coke Strength

Tsubouchi, Naoto; Mochizuki, Yuji; Ono, Yohei; Uebo, Kazuya; Takanohashi, Toshimasa; Sakimoto, Naoto

doi:10.2355/isijinternational.54.2439

Cited by 21 publications

(23 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, the N/C ratios for the 1200 and 1350 °C chars, normalized to that of the 1000 °C char, were lower at higher temperatures, irrespective of the coal type. These observations demonstrated that the N 2 increase was primarily due to char‐N after devolatilization …”

Section: Resultscontrasting

confidence: 57%

Formation of molecular nitrogen and hydrogen sulfide during high‐temperature pyrolysis of coals

Tsubouchi

2014

Asia-Pacific J Chem Eng

Self Cite

View full text Add to dashboard Cite

Nitrogen and sulfur release from eleven coals during pyrolysis at high temperatures (≥1000°C) was studied in both fixed-bed and free-fall quartz reactors. Yields of N 2 , char-N and H 2 S were found to depend strongly on the pyrolysis conditions, such that N 2 and H 2 S yields increased with increasing pyrolysis temperature and coal particle residence time, whereas char-N decreased. There was also a strong inverse correlation between N 2 and char-N yields, suggesting that the majority of N 2 is produced from char-N through solid-phase reactions. H 2 S formation had no clear relationship with the carbon and sulfur contents of the parent coal. Demineralization with HCl washing was observed to remove primarily Ca 2+ cations from four low rank coals examined and to increase the char-N and H 2 S yields but decrease N 2 generation. In contrast, the addition of 3 wt% Ca to the four coals drastically enhanced N 2 formation and suppressed the formation of char-N and H 2 S. The X-ray diffraction analysis of the chars derived from Ca-loaded coals revealed that the Ca was present primarily as CaO with an average crystallite size of 15-45 nm, and that the presence of the Ca promoted carbon crystallization. Small diffraction peaks due to CaS were also observed. Fine particles of CaO may not only promote N 2 formation through solid phase reactions of char-N but undergo sulfur capture reactions. A mechanism for the Ca-catalyzed N 2 formation was discussed in terms of solid-solid reactions between CaO particles and char-N.

show abstract

Section: Resultscontrasting

confidence: 57%

Formation of molecular nitrogen and hydrogen sulfide during high‐temperature pyrolysis of coals

Tsubouchi

2014

Asia-Pacific J Chem Eng

Self Cite

View full text Add to dashboard Cite

show abstract

“…Coal tar pitch contains numerous hydrocarbons, 20) those that effectively increased the MD, such as coronene, those that hardly contribute to increase in MD, such as PAHs with molecular weights in the range 152.19-178. 23, and those that decreased the MD, such as PAHs containing oxygen. Since coal tar pitch contains an effective component, an ineffective component and an inhibitory component in MD, it is considered that the increase in MD when coronene was added was higher than when coal tar pitch was added.…”

Section: Dilatation and Interactions Between Coal And Hydrocarbon Reamentioning

confidence: 99%

“…20) In the previous study, changes in the fluidity of coal were investigated when several hydrocarbon reagents were used. For example, polycyclic aromatic hydrocarbons, 21) aromatic hydrocarbons containing nitrogen, [21][22][23][24] and aromatic hydrocarbons containing oxygen. 21,25) These investigations revealed that the fluidity of coal increased when a PAH with a high boiling point or an aromatic hydrocarbon containing nitrogen was used, but decreased when an aromatic hydrocarbon containing oxygen was used.…”

Section: Introductionmentioning

confidence: 99%

Effects of Hydrocarbon Addition on Increase in Dilatation of Coal

et al. 2019

Self Cite

View full text Add to dashboard Cite

The addition of coal tar pitch mainly composed of polycyclic aromatic hydrocarbons (PAHs), increases the dilatation of coal. We investigated the effect of PAHs on the maximum dilatation (MD) of hard coking coals and semi-soft coking coals. Twenty-six kinds of PAHs and aliphatic hydrocarbon were used as additive agents. The use of a PAH with a molecular weight in the range 152.19-178.23 as an additive agent almost unchanged the MD. When a PAH with a molecular weight in the range 178.23-378.47 was added to the coal, the MD of the coal increased. The increase in MD achieved with the addition of 9,10-dihydrophenanthrene was larger than that obtained with the addition of phenanthrene. This is likely because the hydrogen atoms in the ninth and tenth positions in 9,10-dihydrophenanthrene inhibit the polymerization of the coal structure. The MD was hardly affected by the addition of a linear aliphatic hydrocarbon (C 28 H 58) but MD decreased due to the addition of anthraquinone with carbonyl carbon. When a PAH with nonplanar structure was added to the coal, the increase in MD was smaller than when a PAH with planar structure was added.

show abstract

“…the interactions between coal and chemical substances. [8][9][10] Koyano et al 9) investigated influences of polycyclic aromatics on coal fluidity. They reported that polycyclic aromatics with higher molecular weight and higher boiling point had superior effect on coal fluidity and coke strength.…”

Section: Addition Effect Of Aromatic Amines On Coal Fluidity and Cokementioning

confidence: 99%

“…They reported that polycyclic aromatics with higher molecular weight and higher boiling point had superior effect on coal fluidity and coke strength. Tsubouchi et al 10) investigated the effect of nitrogen-containing aromatic compounds on coal fluidity and coke strength. And they reported that only indole was effective in improving coal fluidity and coke strength among nitrogen-containing aromatic compounds.…”

Section: Addition Effect Of Aromatic Amines On Coal Fluidity and Cokementioning

confidence: 99%

Addition Effect of Aromatic Amines on Coal Fluidity and Coke Strength

Otsuka¹,

Dohi²,

Matsui³

et al. 2019

ISIJ Int.

View full text Add to dashboard Cite

BackgroundToday, high-strength coke is actively pursued to operate blast furnace with low reducing agent. 1) Caking properties are the important parameters in coal blending techniques to produce high-strength coke. 2) In particular, Gieseler plastometer method standardized by JIS M8801 have long been used for measuring 'fluidity' as caking properties. On the other hand, recently, the amount of high-quality coal with high fluidity has been limited. The tight supply and rising price of high-quality coal with high fluidity is an inevitable problem in Japan, therefore development of technique to utilize slightly and non-caking coals is required. To cope with this problem, caking additive method which improves fluidity of coal has been developed and commercialized. 3-7) It is known that caking additives improve coal fluidity, promote liquid-phase carbonization, increase anisotropic texture in coke. However, mechanism of caking additives for improving coal fluidity is still unclear. It is important to search for more effective chemical substances to clarify the mechanism of caking additives to improve fluidity of coal.In order to clarify effective chemical substances to improve coal fluidity, there are a number of studies on Coal fluidity is an important parameter in coal blending techniques for coke making because it strongly influences coke qualities. On the other hand, recently, the amount of high fluidity coal has been limited. To cope with this problem, caking additive method which improves fluidity of coal has been developed and commercialized. However, since tight supply of high fluidity coal is anticipated in the future, it is of great importance to develop more effective caking additive. Therefore, in this study, we investigated effect of 11 kinds of polyaromatic hydrocarbons which include oxygen, sulfur and nitrogen containing compounds on coal fluidity in order to search for more effective chemical substances. The additives were added to low fluidity coal, and fluidity analyses were carried out according to the Gieseler plastometer method. Addition of sulfur and oxygen containing compounds lowered fluidity of coal, whereas addition of aromatic amines enhanced fluidity of coal. Coal fluidity ameliorated with increasing the molecular weight of aromatic amine, and N,N'-di-2-naphthyl-1,4-phenylenediamine (DNPD) was the most effective aromatic amine in this study. Carbonization tests in an electric furnace were conducted to investigate an effect of DNPD on coke strength. As a result of adding only 1 wt% DNPD, fluidity of blended coal and coke strength (Drum Index) were highly improved. KEY WORDS: cokemaking; coal thermoplasticity; caking additive; aromatic amine; slightly caking coal.the interactions between coal and chemical substances. 8-10) Koyano et al. 9) investigated influences of polycyclic aromatics on coal fluidity. They reported that polycyclic aromatics with higher molecular weight and higher boiling point had superior effect on coal fluidity and coke strength. Tsubouchi et al. 10) investigated the e...

show abstract

Sulfur and Nitrogen Distributions during Coal Carbonization and the Influences of These Elements on Coal Fluidity and Coke Strength

Cited by 21 publications

References 33 publications

Formation of molecular nitrogen and hydrogen sulfide during high‐temperature pyrolysis of coals

Formation of molecular nitrogen and hydrogen sulfide during high‐temperature pyrolysis of coals

Effects of Hydrocarbon Addition on Increase in Dilatation of Coal

Addition Effect of Aromatic Amines on Coal Fluidity and Coke Strength

Contact Info

Product

Resources

About