scholarly journals Influence of High Temperature Thermal Radiation on the Transition Characteristics of Coal Oxidation and Spontaneous Combustion

2021 ◽  
Vol 8 ◽  
Author(s):  
Liancong Wang ◽  
Weizhao Hu ◽  
Yuan Hu
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Thermal Radiation ◽  
Heat Release ◽  
Release Rate ◽  
Carbon Dioxide Emissions ◽  
Bituminous Coal ◽  
Spontaneous Combustion ◽  
Total Carbon ◽  
Coal Oxidation

In the goaf of the coal mine, there will be some high-temperature points before or during the fire. Under certain conditions, these high-temperature points will radiate heat to the surrounding coal in the form of thermal radiation, which, in turn, may also ignite the coal. Taking this situation into consideration, this study aims to investigate the influence of high-temperature thermal radiation on the transformation characteristics of coal oxidation and spontaneous combustion using the high-temperature thermal radiation method. The results show that an increase in thermal radiation value reduces the ignition time of coal gradually. The peak heat release rate, total heat release, peak smoke release rate, and total smoke release gradually increase. Additionally, the total carbon monoxide release reduces gradually, and the peak carbon dioxide production rate increases gradually. It is worth noting that as the heat radiation value increases, the peak value of CO production rate of lignite and bituminous coal is noted to decrease gradually, whereas that of anthracite increases gradually. The total carbon dioxide emissions of bituminous coal and anthracite increased gradually, whereas the total carbon dioxide emissions of lignite increased firstly and then decreased. This work proposes a novel method to study the coal oxidation and spontaneous combustion by a widely-recognized combustion apparatus.

scholarly journals Mechanism of Fire Prevention with Liquid Carbon Dioxide and Application of Long-Distance Pressure-Holding Transportation Technology Based on Shallow Buried and Near-Horizontal Goaf Geological Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Naifu Cao ◽  
Yuntao Liang
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Spontaneous Combustion ◽  
Co2 Concentration ◽  
Mining Area ◽  
Fire Prevention ◽  
Coal Oxidation ◽  
Liquid Carbon ◽  
Liquid Co2 ◽  
And Diffusion

Shallow burial, very close coal seam groups, and spontaneous combustion are typical characteristics of most coal seams in the Shendong mining area, China. With the continuous extension of the production level of various mines, some mining areas have gradually shown complex production conditions including multiple types of fire forms such as those in coal fields, small kilns, and multilayer mined-out and hidden high-temperature areas, resulting in fire control difficultly and posing threats to safety. With the aim of limiting the above problems, in this work, the liquid carbon dioxide fire prevention technology is focused on. Phase change and migration law of CO2 in the goaf are studied. Through the study on the influence of the use of liquid CO2 on the cooling law of high-temperature coal and on its spontaneous combustion characteristics and through thermal analysis experiments, it was observed that the porosity of loose coal has a significant impact on the cooling effect of carbon dioxide. Moreover, it was emphasized that the higher the CO2 concentration, the higher the rise in temperature of coal oxidation, and the increase of CO2 concentration was able to affect apparent activation of coal oxidation, leading to a theoretical basis to explain the effect of CO2 in inhibiting coal spontaneous combustion. The utilization of Fluent numerical modeling allowed us to simulate the diffusion radius of liquid CO2 injected into the goaf, to study the effective inerting radius of liquid CO2 on the left coal in the goaf. After comprehensive analysis of experiments and numerical simulations, appropriate equipment and process flow are selected and designed. Taking the Huojitujing well of Daliuta Coal Mine in Shendong mining area as the industrial test site, an intelligent pressure-holding transportation of liquid CO2 in the 1000 m transportation pipeline was developed. The surface liquid CO2 infusion capacity was 20 t/h, and the pressure-holding interval at the end of the transportation pipeline was determined to be 1.0–2.3 MPa. The maximum diffusion radius of the mined-out area is 300 m under the effect of positive air flow and self-expansion and diffusion of CO2 gas in the roadway. Under the influence of reverse wind flow and self-expansion and diffusion, the diffusion radius of the goaf is 150 m, and the maximum storage time of gaseous CO2 in the goaf is 27 h. Liquid CO2 was injected into the area with relevant presence of CO, an indicator of possible fires. Practice has proved that, after 65 hours and two perfusion processes, the CO concentration dropped from 790 ppm to 41 ppm, which indicates that liquid CO2 has a significant effect on fire prevention.

scholarly journals Investigation of the kinetics of spontaneous combustion of the major coal seam in Dahuangshan mining area of the Southern Junggar coalfield, Xinjiang, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Shen ◽  
Qiang Zeng
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Heating Temperature ◽  
Characteristic Temperature ◽  
Mining Area ◽  
Particle Sizes ◽  
Coal Oxidation ◽  
Increasing Temperature

AbstractIn the present paper, with using diverse methods (including the SEM, the XRD, the TPO, the FTIR, and the TGA) , the authors analysed samples of the major coal seam in Dahuangshan Mining area with different particle sizes and with different heated temperatures (from 50 to 800 °C at regular intervals of 50 °C). The results from SEM and XRD showed that high temperature and high number of pores, fissures, and hierarchical structures in the coal samples could facilitate oxidation reactions and spontaneous combustion. A higher degree of graphitization and much greater number of aromatic microcrystalline structures facilitated spontaneous combustion. The results from TPO showed that the oxygen consumption rate of the coal samples increased exponentially with increasing temperature. The generation rates of different gases indicated that temperatures of 90 °C or 130 °C could accelerate coal oxidation. With increasing temperature, the coal oxidation rate increased, and the release of gaseous products was accelerated. The FTIR results showed that the amount of hydroxide radicals and oxygen-containing functional groups increased with the decline in particle size, indicating that a smaller particle size may facilitate the oxidation reaction and spontaneous combustion of coal. The absorbance and the functional group areas at different particle sizes were consistent with those of the heated coal samples, which decreased as the temperature rose. The results from TGA showed that the characteristic temperature T3 declined with decreasing particle size. After the sample with 0.15–0.18 mm particle size was heated, its carbon content decreased, and its mineral content increased, inhibiting coal oxidation. This result also shows that the activation energy of the heated samples tended to increase at the stage of high-temperature combustion with increasing heating temperature.

The Pre-Controlling Technology of Spontaneous Combustion in Gutter-Up Gob for Fully Mechanized Top-Coal Caving Face

2013 ◽  
Vol 634-638 ◽  
pp. 3688-3695 ◽  
Author(s):  
Yang Xiao ◽  
Shu Gang Li ◽  
Jun Deng ◽  
Xu Wang
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Fly Ash ◽  
Coal Mining ◽  
Spontaneous Combustion ◽  
Good Effect ◽  
Air Leakage ◽  
Coal Spontaneous Combustion ◽  
Liquid Carbon ◽  
Fire Extinguishing

In China, as popularizing the technology of fully mechanized top-coal mining and increasing the strength and depth of mining, the gutter-up gob can be formed. But the work of fire preventing and extinguishing for its coal spontaneous combustion is more complexity and difficulty. In this paper, based on geology parameters and mining practice for 93up12 fully mechanized top-coal caving face in Nantun coalmine, the form and character of gutter-up gob are analyzed. According to the hidden danger of high temperature for spontaneous combustion in the gob, we adopt the comprehension technologies of fire extinguishing and preventing which include sealing air-leakage, grouting, and injecting compound gel with fly-ash, foam of retarding oxidation, liquid carbon dioxide, and gas of nitrogen. By putting in practice the pre-controlling technology in gutter-up gob and monitoring data of target gases, it obtains a good effect and ensures the safety in production of the fully-mechanized top-coal caving face.

Comparative Study on BRIC Carbon Dioxide Emissions - Econometric Empirical Test Based on Cross-Century Time Series Data

2012 ◽  
Vol 616-618 ◽  
pp. 1512-1515
Author(s):  
Wei Hua Du
Keyword(s):  
Carbon Dioxide ◽  
Time Series ◽  
Carbon Dioxide Emissions ◽  
Time Series Data ◽  
Comparative Statics ◽  
Total Carbon ◽  
Series Data ◽  
Per Capita Gdp ◽  
Bric Countries ◽  
Per Capita

Take for example the BRIC economies: Brazil, Russia, India and China. We investigated the time series data on the relationship between carbon dioxide emission and economic growth in these fast-growing developing countries by both comparative statics and comparative dynamics. The results show that there is the monotonic relationship between total carbon dioxide emissions, carbon dioxide emissions per capita and per capita GDP in any one of the BRIC countries. And there is decreasing relationship between the carbon dioxide emissions per unit GDP and per capita GDP.

Electricity production and its effects on carbon dioxide emissions in the Kingdom of Saudi Arabia: إنتاج الكهرباء وآثاره في انبعاثات ثاني أكسيد الكربون في المملكة العربية السعودية

2021 ◽  
Vol 5 (3) ◽  
pp. 134-108
Author(s):  
Zakiah Radhi Alhajji, Mohamed Elsayed Hafez Ali Zakiah Radhi Alhajji, Mohamed Elsayed Hafez Ali
Keyword(s):  
Carbon Dioxide ◽  
Saudi Arabia ◽  
Carbon Dioxide Emissions ◽  
Fossil Fuels ◽  
Electric Energy ◽  
Total Carbon ◽  
Electricity Production ◽  
Energy Productivity ◽  
Gulf Region ◽  
Kingdom Of Saudi Arabia

Because of increased demand for electrical energy in the Kingdom of Saudi Arabia, which has resulted in an increase in carbon dioxide emissions, the electricity system in the Kingdom of Saudi Arabia is the largest in the Gulf region and the Arab world, with approximately 61.7 gigatons (GW) of peak demand and 89.2 gigatons (GW) of available capacity in 2018 of electricity power. It has grown rapidly over more than 20 years and has almost doubled in size since 2000. Where we observe that the total carbon dioxide emissions in the Kingdom of Saudi Arabia from 1990 to 2020; where shows rapid growth in emissions of carbon dioxide and greenhouse gases, as it was found that CO2 emissions in 1990 amounted to 151 million metric tons compared to 2011 when it reached about 435 million metric tons, and the increase continued until 2020 when it reached about 530 million metric tons. The comprehensive study relied on time series analysis to carefully analyze the electric energy productivity rate from fossil fuels and the significant amount of carbon dioxide emissions typically resulting from promptly burning fossil fuels to naturally produce electric energy. Therefore, the Kingdom of Saudi Arabia, through Vision 2030 and the Paris Agreement on Climate Change, looks to reduce the rate of carbon dioxide emissions in the field of electric power generation by diversifying the fuels used or replacing them with clean and renewable energy such as solar and wind energy.

Calculations of the Heat Release Rate by Oxygen Consumption for Various Applications

1984 ◽  
Vol 2 (5) ◽  
pp. 380-395 ◽  
Author(s):  
W.J. Parker
Keyword(s):  
Oxygen Consumption ◽  
High Temperature ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fire Tests ◽  
Total Heat Release ◽  
Exhaust Duct ◽  
Closed Systems ◽  
Gas Burner

The calculation of heat release rate by oxygen consumption is based on the assumption that all materials release approximately the same amount of heat per unit mass of oxygen consumed. This technique is now being employed to determine the heat release rate of materials in various heat release rate cal orimeters. Other uses include the heat release rate of assemblies in the fire en durance furnaces and the total heat release rate in room fire tests. These dif ferent applications lead to different experimental procedures which require dif ferent formulas. The experimental choices or constraints include open or closed systems, paramagnetic or high temperature oxygen analyzers, CO2 analyzers or CO2 traps, and the use of a gas burner whose heat release rate must be deducted from the total. Various assumptions about CO levels in the exhaust duct and vitiation and humidity in the incoming air are made. General formulas for the heat release rate by oxygen consumption are developed in this paper from which the formulas for specific applications can easily be derived.

Study on Low-Temperature Oxidation’s Endothermic Character of Coal with Comparative-Oxidation Method

2012 ◽  
Vol 577 ◽  
pp. 39-42
Author(s):  
Chang Lu ◽  
Yuan Qing Liang ◽  
Hui Hui Li
Keyword(s):  
Low Temperature ◽  
Energy Conservation ◽  
Heat Release ◽  
Release Rate ◽  
Coal Sample ◽  
Spontaneous Combustion ◽  
Storage Conditions ◽  
Equation Model ◽  
Oxidation Method ◽  
Temperature Controlled

In this paper air was passed through into one progress temperature-controlled box with coal sample and nitrogen into another as comparison during the procedure of coal’s low-temperature （10～80°C）oxidation . Draw the heating curves and heating rate curve, and equation model is built combined with energy conservation, then concludes the heat release rate of the coal samples in the air conditions. The experimental results show that the condition with air is more close to the storage conditions of coal such as transportation in reality, which is very significant to prevent the spontaneous combustion of coals

Modified carbon-dioxide measurement to predict the heat release rate of fire burning in a compartment based on the three-zone model

2019 ◽  
Vol 43 (3) ◽  
pp. 256-265 ◽  
Author(s):  
Ying Zhang ◽  
Kaixuan Tang ◽  
Hong Duan ◽  
Yi Niu ◽  
Xianjia Huang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Zone Model ◽  
Carbon Dioxide Measurement
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