Study on Co-Combustion Characteristics of Coals under Pure Oxygen Atmosphere

In this study, the combustion behaviors of three kinds of coal and their mixtures under the pure oxygen and air atmosphere were studied by using a thermo-gravimetric analyzer. The combustion characteristics such as ignition and burnout behavior were investigated in the temperature from 20°C to 800°C. The influence of mixing Shenhua coal with Huaibei bituminous and Sanming anthracite coal on combustion characteristics was conduced. The results obtained show that pure oxygen content accelerated the coal burning process greatly; the coal volatile matter started to release at a lower temperature and the coal burning process was finished earlier compared with the burning process under the air atmosphere. The addition of Shenhua coal improved the combustion characteristics of both Huaibei bituminous coal and Sanming anthracite in a different way. For the Huaibei bituminous coal, both the ignition and burnout temperature decreased linearly with the increasing ratio of Shenhua coal; while for the Sanming anthracite, the addition of Shenhua coal greatly lowered the mixture ignition temperature, and the burnout temperature was nearly the same. The activation energy of the mixture coal with Shenhua and Huaibei coal reduced with the ratio of Shenhua coal. For the Shenhua and Sanming coal mixture, the activation energy changed differently at the two burning stages.

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An Investigation into the Combustion of Mixed Fuel Consisting of Bituminous Coal and Crude Bio-Oil

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.773-774.1184 ◽

2015 ◽

Vol 773-774 ◽

pp. 1184-1188

Author(s):

Hazlin Hamdan ◽

Munawar Zaman Shahruddin ◽

Ahmad Rafizan Mohamad Daud ◽

Syed Shatir A. Syed-Hassan

Keyword(s):

Gas Flow ◽

Bituminous Coal ◽

Decomposition Reaction ◽

Volatile Matter ◽

Kinetic Evaluation ◽

Exponential Factor ◽

Air Atmosphere ◽

Coal Fuel ◽

Bio Oil ◽

Lower Temperature

The combustion of bituminous coal, bio-oil, and their slurry mixtures were performed under air atmosphere using Thermogravimetric Analyzer (TGA). All samples were run from room temperature to 110°C and held for 10 minutes before the temperature was ramped to 1100°C and held again for 10 minutes at 1100°C at the heating rate of 10°C/min and gas flow rate of 50mL/min. Kinetic evaluation was conducted using a simple Arrhenius-type kinetic model with first-order decomposition reaction. Apparent activation energy, Ea, and pre-exponential factor, A, were calculated from the modelling equation. Results reveal that the reactivity of CBS fuel is higher than a single coal fuel to which the addition of bio-oil helps to increase the combustion performance of the blends. The optimum fuel ratio appears at 50:50 ratio with equal contribution of coal and bio-oil properties that contribute to the increase in volatile matter causing maximum combustion rate achievable at much lower temperature compared to single coal fuel.

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Emission factors and light absorption properties of brown carbon from household coal combustion in China

10.5194/acp-2016-1090 ◽

2017 ◽

Cited By ~ 1

Author(s):

Jianzhong Sun ◽

Guorui Zhi ◽

Regina Hitzenberger ◽

Yingjun Chen ◽

Chongguo Tian ◽

...

Keyword(s):

Light Absorption ◽

Climate Modeling ◽

Emission Factors ◽

Volatile Matter ◽

Integrating Sphere ◽

Brown Carbon ◽

Carbonaceous Particles ◽

Coal Burning ◽

Anthracite Coal ◽

Climate Cooling

Abstract. Brown carbon (BrC) draws increasing attention due to its effects on climate and other fields. In China, household coal burned for heating/cooking purposes releases huge amounts of carbonaceous particles every year; however, BrC emissions have rarely been estimated in a persuasive manner due to the unavailable emission characteristics. Here 7 coals jointly covering geological maturity from low to high were burned in 4 typical stoves at both chunk and briquette styles. The optical integrating sphere (IS) method was applied to measure the emission factors (EFs) of BrC and BC via an iterative process using the different spectral dependence of light absorption for BrC and BC. It is found that (i) the average EFs of BrC for anthracite coal chunks and briquettes are (1.08 ± 0.80) g kg−1 and (1.52 ± 0.16) g kg−1, respectively, and those for bituminous coal chunks and briquettes are (8.59 ± 2.70) g kg−1 and (4.01 ± 2.19) g kg−1, respectively, reflecting a more significant decline of BrC EFs for bituminous coals than for anthracites due to briquetting, (ii) the BrC EF peaks at the middle of coal's geological maturity, displaying a bell shaped curve between EF and volatile matter (Vdaf), (iii) the calculated BrC emissions from China's residential coal burning amounted to 592 Gg (1 Gg = 109 g) in 2013, which is nearly half of China's total BC emissions, (iv) absorption Ångström exponent (AAEs) of all coal briquettes are higher than those of coal chunks, indicating that the measure of coal briquetting increases the BrC / BC emission ratio and thus offsets some of the climate cooling effect of briquetting, and (v) in the scenario of current household coal burning in China, solar light absorption by BrC (350–850 nm in this study) accounts for more than a quarter (0.265) of the total absorption. This implies the significance of BrC to climate modeling.

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Experimental Research on Catalytic Combustion Characteristics of Inferior Coal and Sludge Mixture

Journal of Energy Resources Technology ◽

10.1115/1.4037373 ◽

2017 ◽

Vol 140 (3) ◽

Cited By ~ 9

Author(s):

Yunfei Yan ◽

Shuai Feng ◽

Li Zhang ◽

Lixian Li ◽

Lei Zhang ◽

...

Keyword(s):

Activation Energy ◽

Thermogravimetric Analysis ◽

Metal Oxides ◽

Apparent Activation Energy ◽

Combustion Characteristics ◽

Combustion Dynamics ◽

Weight Losses ◽

Coal Sludge ◽

Lower Temperature ◽

Catalytic Effects

Catalytic effects of metal oxides on combustion characteristics of inferior coal, sludge, and their mixture were investigated by thermogravimetric analysis. Combustion and thermal dynamic characteristics including ignition temperatures, apparent activation energy, and frequency factors of inferior coal, sludge, and their mixture were observed. The catalytic effects and mechanism of combustion were discussed. Results showed that thermal gravity analysis (TG) and derivative thermogravimetric analysis (DTG) curves of coal and sludge shifted to lower temperature side, the weight losses increased, and the ignition performance was improved with the addition of metal oxides CaO, Al2O3, and K2O. The combustion dynamics analysis showed that the apparent activation energy of cocombustion of coal blending sludge decreased by 11–20% and the frequency factors increased by 20–30%. The minimum apparent activation energy and the maximum frequency factors were obtained in the presence of K2O, indicating that the catalytic effect of K2O was most significant.

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A Evaluation on Pulverized Coal Combustion Properties Using a Thermogravimetric Analyze Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.423-426.609 ◽

2013 ◽

Vol 423-426 ◽

pp. 609-613 ◽

Cited By ~ 2

Author(s):

Yan Hong Gao ◽

Ling Tao Bian

Keyword(s):

Particle Size ◽

Bituminous Coal ◽

Low Cost ◽

Research Work ◽

Volatile Matter ◽

Good Effect ◽

Ignition Point ◽

Anthracite Coal ◽

Combustion Properties ◽

Experimental Researches

In the present research work, volatile matter, influences of reaction temperature and particle size on combustion performance were investigated. Important results were obtained by experimental researches. Ignition point of anthracite coal/bituminous coal blends decreased with volatile matter in blend and combustion was improved. Burnout of coal blends decreased as a function of particle size. However, similar effects were gained when particle size less than 0.074mm accounted for 70%, 60% and 50%, respectively. By contrast, the ratio of 50% was a better choice for good effect and low cost.

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Emission factors and light absorption properties of brown carbon from household coal combustion in China

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-4769-2017 ◽

2017 ◽

Vol 17 (7) ◽

pp. 4769-4780 ◽

Cited By ~ 40

Author(s):

Jianzhong Sun ◽

Guorui Zhi ◽

Regina Hitzenberger ◽

Yingjun Chen ◽

Chongguo Tian ◽

...

Keyword(s):

Light Absorption ◽

Climate Modeling ◽

Emission Factors ◽

Volatile Matter ◽

Integrating Sphere ◽

Brown Carbon ◽

Carbonaceous Particles ◽

Coal Burning ◽

Anthracite Coal ◽

Climate Cooling

Abstract. Brown carbon (BrC) draws increasing attention due to its effects on climate and other environmental factors. In China, household coal burned for heating and cooking purposes releases huge amounts of carbonaceous particles every year; however, BrC emissions have rarely been estimated in a persuasive manner due to the unavailable emission characteristics. Here, seven coals jointly covering geological maturity from low to high were burned in four typical stoves as both chunk and briquette styles. The optical integrating sphere (IS) method was applied to measure the emission factors (EFs) of BrC and black carbon (BC) via an iterative process using the different spectral dependence of light absorption for BrC and BC and using humic acid sodium salt (HASS) and carbon black (CarB) as reference materials. The following results have been found: (i) the average EFs of BrC for anthracite coal chunks and briquettes are 1.08 ± 0.80 and 1.52 ± 0.16 g kg−1, respectively, and those for bituminous coal chunks and briquettes are 8.59 ± 2.70 and 4.01 ± 2.19 g kg−1, respectively, reflecting a more significant decline in BrC EFs for bituminous coals than for anthracites due to briquetting. (ii) The BrC EF peaks at the middle of coal's geological maturity, displaying a bell-shaped curve between EF and volatile matter (Vdaf). (iii) The calculated BrC emissions from China's residential coal burning amounted to 592 Gg (1 Gg  =  109 g) in 2013, which is nearly half of China's total BC emissions. (iv) The absorption Ångström exponents (AAEs) of all coal briquettes are higher than those of coal chunks, indicating that the measure of coal briquetting increases the BrC ∕ BC emission ratio and thus offsets some of the climate cooling effect of briquetting. (v) In the scenario of current household coal burning in China, solar light absorption by BrC (350–850 nm in this study) accounts for more than a quarter (0.265) of the total absorption. This implies the significance of BrC to climate modeling.

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Investigation of Lignite Combustion Characteristics with Thermal Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.614-615.25 ◽

2012 ◽

Vol 614-615 ◽

pp. 25-30

Author(s):

Ming Qiang Liu ◽

Jian Zhong Liu ◽

Yu Jie Yu ◽

Zhi Hua Wang ◽

Jun Hu Zhou ◽

...

Keyword(s):

Activation Energy ◽

Maximum Rate ◽

Bituminous Coal ◽

Combustion Characteristics ◽

High Quality ◽

Combustion Performance ◽

Characteristic Temperatures ◽

Rate Of Combustion ◽

Jander Model ◽

Better Than

Combustion characteristics of three types of lignite (coming from Indonesia, Ximeng, Hami), and a bituminous coal from Shenfu were studied by thermogravimetric analysis (TGA). Combustion parameters including characteristic temperatures, maximum rate of combustion, combustion performance index and activation energy of samples were analyzed. Kinetic parameters of samples were calculated using Jander model. The results showed that the characteristic temperatures of lignite samples are lower than that of bituminous coal. Indonesian lignite has the best combustion performance and the lowest activation energy. It indicates that high quality lignite such as Indonesian lignite has good combustion performance, even better than some bituminous coal, which makes it possible to use lignite by bulk combustion.

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A Comparison of Combustion of Coal Chars in O2/CO2 and O2/N2 Mixtures - Isothermal TGA Studies

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1994 ◽

2009 ◽

Vol 7 (1) ◽

Cited By ~ 2

Author(s):

Hao Liu

Keyword(s):

Activation Energy ◽

Bituminous Coal ◽

Nitrogen Gas ◽

Char Combustion ◽

Temperature Range ◽

Anthracite Coal ◽

Effectiveness Factors ◽

Combustion Tests ◽

Isothermal Combustion ◽

Kinetics Of

Two chars prepared from parent coals of a high volatile bituminous coal and an anthracite coal were subjected to isothermal combustion tests in a thermogravimetric analyser (TGA). The chars were burned in mixtures of O2/CO2 and O2/N2 with O2 concentrations of 3%, 6%, 10%, 21% and 30% and combustion temperature ranging from 723 K to 1163 K. Experimental results show that replacing the inert nitrogen gas in the oxidizer with CO2 has little influence on the measured reactivity of coal chars under conditions of the experiments. The measured reactivity of each char was found to be approximately first order (0.88 0.90) to the concentration of O2 in the O2/CO2 mixtures. As char combustion tests were conducted under relatively high temperatures conditions, internal and external effectiveness factors were estimated in order to derive combustion kinetics of both chars. The values of activation energy for both chars, obtained by taking account of both the internal and external effectiveness factors (i.e. with correction), were very much in line with the literature data. The activation energy of the bituminous coal char combustion in O2/CO2 was found to be 96323 (without correction) 108893 (with correction) kJ/kmol within the temperature range of 723 873 K, whereas the activation energy of the anthracite char was found to be 125716 (without correction) 140486 (with correction) kJ/kmol within the temperature range of 773 973 K.

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