Interaction between volatile-N and char-N and their contributions to fuel-NO during pulverized coal combustion in O2/CO2 atmosphere at high temperature

Wu, Xiaofeng; Fan, Weidong; Ren, Peng; Liu, Zhuang; Shen, Pinghong

doi:10.1016/j.fuel.2019.115856

Cited by 32 publications

(12 citation statements)

References 31 publications

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“…The NO x could be roughly divided into volatile-NO x released during the combustion of volatile and char-NO x released during char combustion. 16 To obtain the correlation between NO x release and the combustion process, the conversation ratio of carbon in fuel to CO 2 (α C ) was studied, and α C as a function of time t is calculated as follows where m t (CO 2 ) denotes the amount of CO 2 released before time t , and m 0 (CO 2 ) denotes the total amount of CO 2 released during the whole combustion process. The amount of CO 2 is obtained by the line integral of CO 2 release curves versus time.…”

Section: Resultsmentioning

confidence: 99%

“… 14 The synergistic effect on NO x and SO 2 reduction was observed during the cocombustion of SS and three kinds of biomasses. 15 Meanwhile, the study on volatile-N and char-N during pulverized coal combustion in the O 2 /CO 2 atmosphere at a high temperature 16 helped obtain the fuel nitrogen conversion mechanism. Previous research on NO x emission mainly focused on the total yield of NO x during combustion, whereas the relevance between NO x release and combustion process has not been discussed in detail.…”

Section: Introductionmentioning

confidence: 99%

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Research on Thermal Behaviors and NO_x Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

et al. 2022

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To investigate the thermal behaviors and NO x emission properties during combustion of sewage sludge (SS), sawdust (SD), and their blends (SS5SD5, SS3SD7, and SS1SD9 with SD proportions of 50, 70, and 90 wt %, respectively), tests were conducted using thermogravimetry–mass spectrometry (TG-MS), Fourier transform infrared spectroscopy (FTIR), and a tube furnace in this study. Results indicated that hydrogen in the fuel was mainly released during volatile combustion, and carbon conversion proceeded during the whole combustion process. With the SD proportion increasing, samples exhibited better combustion characteristics. Compared to SD, SS emitted more NO x due to its higher nitrogen content but showed lower conversion ratios from fuel nitrogen to NO x , and the NO x yields decreased significantly with the increase in SD proportion. NO x emissions of higher volatile samples were more sensitive to temperature, and NO x yields of SD and SS1SD9 continued to decrease from 800 to 1000 °C, whereas NO x yields of SS, SS5SD5, and SS3SD7 changed slightly from 800 to 900 °C and decreased significantly from 900 to 1000 °C. Synergistic effects of cocombustion on NO x emission varied with the blending ratio and temperature. SS5SD5 and SS3SD7 always presented a positive NO x reduction performance, and SS1SD9 exhibited opposite NO x reduction effects at different temperatures. Synthetically considering the SS disposal capacity, combustion characteristic, and NO x yield, an SS proportion of around 30% in blends is more recommended in practical applications.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Research on Thermal Behaviors and NO_x Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

et al. 2022

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“…Details about this setup can be accessed in our previous research works. 16,17 A separated combustion mode was considered in the present work, as shown in Figure 1. In this mode, the coal combustion process was divided into two periods: the volatile combustion and the char combustion.…”

Section: Experimental Setup and Methodsmentioning

confidence: 99%

“…Based on this experimental system, many experiments have been conducted in recent years. Details about this setup can be accessed in our previous research works. , …”

Section: Experimental Setup and Methodsmentioning

confidence: 99%

Effect of CO₂ on N Distribution in Pyrolysis and Oxidation of Volatile N and Char N in Oxy-Fuel Combustion at High Temperatures

Fan

Liu

et al. 2020

Energy Fuels

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In this paper, the coal combustion process was separated into a pyrolysis process, a volatile oxidation process, and a char oxidation process by utilizing a high-temperature fixed-bed reactor. Three types of experiments in different atmospheres were designed based on this reactor. The effects of CO 2 on N distribution in pyrolysis (fractions of N in volatile and char) and oxidation of volatile N and char N in oxy-fuel combustion at different temperatures were investigated by comparing different experimental results. The results show that CO 2 pyrolysis (coal pyrolysis in an O 2 /CO 2 atmosphere) inhibited the conversion of fuel N to volatile N at 1000 °C compared to Ar pyrolysis (coal pyrolysis in an O 2 /Ar atmosphere). However, when coal was pyrolyzed between 1150 and 1600 °C, CO 2 reduced the ratio distribution of char N and promoted the conversion of fuel N to volatile N. In the subsequent volatile oxidation process, CO produced by the char-CO 2 gasification reaction during CO 2 pyrolysis decreased the conversion rate of volatile N to volatile NO. During the CO 2 oxidation (oxidation in an O 2 /CO 2 atmosphere) of volatile, CO 2 increases the conversion rate of volatile N to volatile NO. This may result from that the conversion of N intermediates to N 2 O was promoted by CO 2 . In the CO 2 oxidation of char, CO 2 reduces the conversion rate of char N to char NO. Because of the char-CO 2 gasification reaction, the formation of char NO was inhibited. In the whole process of coal combustion, the volatile-NO release amount increases, while the char-NO release amount decreases in a CO 2 atmosphere compared to an Ar atmosphere at different temperatures. Besides, the ratio of volatile NO to fuel NO increases in a CO 2 atmosphere.

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“…Thermal conversion of coal is regarded as one of the main sources of NO x in the atmosphere. , Nitrogen in coal mainly exists in three forms, i.e., pyrrole N, pyridine N, and quaternary N, − among which pyrrole N is the most abundant, accounting for around 50–80 wt % of total nitrogen. During the thermal conversion process, coal is usually decomposed into various products in the absence of oxygen, which then undergo diverse reactions (oxidation, cracking, reforming, etc.)…”

Section: Introductionmentioning

confidence: 99%

Catalytic Mechanism of Calcium on the Formation of HCN during Pyrolysis of Pyrrole and Indole: A Theoretical Study

et al. 2019

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Calcium-based compounds are major inorganic components in coal and also widely used as additives in thermal conversion of coal and, thus, have important effects on the decomposition of nitrogen-containing compounds to form NO x . In this work, the influence of Ca 2+ on the pyrolysis of pyrrole and benzopyrrole (indole) to form HCN, a precursor of NO x , was investigated via a density functional theory (DFT) calculation with B3LYP/6-31+G(d,p) basis set. The results suggest that Ca 2+ has strong interactions with pyrrole and indole by altering the original electron density distribution of the pyrrole ring and the configurations of pyrrole derivatives, respectively. Ca 2+ affects the energy barriers of the elementary pyrolytic reactions (i.e., internal hydrogen transfer, isomerization, and concerted decomposition) and particularly reduces the energy barriers of the ratedetermining steps for HCN formation. In comparison to alkali metal ion Na + , alkali earth metal ion Ca 2+ has a stronger influence on the pyrrole and indole pyrolysis to form HCN.

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Interaction between volatile-N and char-N and their contributions to fuel-NO during pulverized coal combustion in O2/CO2 atmosphere at high temperature

Cited by 32 publications

References 31 publications

Research on Thermal Behaviors and NO_x Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

Research on Thermal Behaviors and NO_x Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

Effect of CO₂ on N Distribution in Pyrolysis and Oxidation of Volatile N and Char N in Oxy-Fuel Combustion at High Temperatures

Catalytic Mechanism of Calcium on the Formation of HCN during Pyrolysis of Pyrrole and Indole: A Theoretical Study

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Interaction between volatile-N and char-N and their contributions to fuel-NO during pulverized coal combustion in O2/CO2 atmosphere at high temperature

Cited by 32 publications

References 31 publications

Research on Thermal Behaviors and NOx Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

Research on Thermal Behaviors and NOx Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

Effect of CO2 on N Distribution in Pyrolysis and Oxidation of Volatile N and Char N in Oxy-Fuel Combustion at High Temperatures

Catalytic Mechanism of Calcium on the Formation of HCN during Pyrolysis of Pyrrole and Indole: A Theoretical Study

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Product

Resources

About

Research on Thermal Behaviors and NO_x Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

Research on Thermal Behaviors and NO_x Release Properties during Combustion of Sewage Sludge, Sawdust, and Their Blends

Effect of CO₂ on N Distribution in Pyrolysis and Oxidation of Volatile N and Char N in Oxy-Fuel Combustion at High Temperatures