scholarly journals Evaluation of parameters to determine the degree of coal dust explosibility

2014 ◽  
pp. 42-54
Author(s):  
Elkin Casas Herrera ◽  
Astrid Blandón Montes ◽  
Jorge Martin Molina-Escobar

Coal dust is highly explosive and caused dozens of victims in Colombia. In this research the most important and direct influence on coal dust, especially those that cause combustion and explosion inside the mine factors were analyzed; is important to discuss the characteristics of each coal mined and processed, for actions that do not compromise the integrity of the staff or facilities. Four (4) channel samples of coal exploitation faces with High Volatile Bituminous C from Cerrejón Formation were collected and analyzed: Proximal (moisture, ash, volatile matter, fixed carbon, total sulfur and calorific value ); petrographic (maceral counting and vitrinite reflectance) and Hardgrove mill index. The samples were crushed to obtain fractions corresponding to meshes 200, 270 and 325 considering those sizes could give greater risks of explosion.The analysis showed that there is a direct relationship between the results of the Hardgrove mill index and the degree of explosiveness in the fraction corresponding to 200 mesh, meaning that a higher rate of milling the greater the degree of explosiveness; a direct relationship between calorific inertinite content range and also observed. The 325 mesh fraction for all samples showed the same degree of explosiveness, which indicates that the grain size and the type of coal maceral not influence the content and coal rank. The flash point decreased for finer grains for all samples. Thus, the size of carbon particle is very important as an indicator in the coal-dust explosion factor: finer particles have greater the likelihood of explosion. The percentage of inertinites has a close relationship with the explosivity index, the higher the content of this maceral, coupled with the fine grain, coal dust behaves like a highly explosive element and generate risks in mining operations.Coal rank is an important factor regard to self combustion and explosion of particles with grain sizes greater 200 mesh. If a low rank coal has susceptible and unstable at high temperature elements and this is combined with high volatile matter and some other influential environmental parameters, such as blow air, dust concentration, humidity, and pressure, among others, the ideal combustion and then a likely violent explosion may affect a large portion of mine.

2014 ◽  
Vol 59 (2) ◽  
pp. 509-516
Author(s):  
Andrzej Olajossy

Abstract Methane sorption capacity is of significance in the issues of coalbed methane (CBM) and depends on various parameters, including mainly, on rank of coal and the maceral content in coals. However, in some of the World coals basins the influences of those parameters on methane sorption capacity is various and sometimes complicated. Usually the rank of coal is expressed by its vitrinite reflectance Ro. Moreover, in coals for which there is a high correlation between vitrinite reflectance and volatile matter Vdaf the rank of coal may also be represented by Vdaf. The influence of the rank of coal on methane sorption capacity for Polish coals is not well understood, hence the examination in the presented paper was undertaken. For the purpose of analysis there were chosen fourteen samples of hard coal originating from the Upper Silesian Basin and Lower Silesian Basin. The scope of the sorption capacity is: 15-42 cm3/g and the scope of vitrinite reflectance: 0,6-2,2%. Majority of those coals were of low rank, high volatile matter (HV), some were of middle rank, middle volatile matter (MV) and among them there was a small number of high rank, low volatile matter (LV) coals. The analysis was conducted on the basis of available from the literature results of research of petrographic composition and methane sorption isotherms. Some of those samples were in the form (shape) of grains and others - as cut out plates of coal. The high pressure isotherms previously obtained in the cited studies were analyzed here for the purpose of establishing their sorption capacity on the basis of Langmuire equation. As a result of this paper, it turned out that for low rank, HV coals the Langmuire volume VL slightly decreases with the increase of rank, reaching its minimum for the middle rank (MV) coal and then increases with the rise of the rank (LV). From the graphic illustrations presented with respect to this relation follows the similarity to the Indian coals and partially to the Australian coals.


2016 ◽  
Vol 62 (3) ◽  
pp. 6-11 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
Aliyu Jauro

Abstract The paper examined physicochemical and thermal characteristics of the newly discovered Garin Maiganga (GMG) coal from Nigeria. The physicochemical characterization comprised of elemental, proximate, calorific value, and classification (rank) analyses. Thermal analysis was examined using combined Thermogravimetric (TG) and Derivative Thermogravimetric analyses (DTG). Hence, the coal was heated from 30°C to 1000°C at 20°C/min under inert conditions to examine its thermal degradation behaviour and temperature profile characteristics (TPC). The results indicated that the GMG coal fuel properties consist of low Ash, Nitrogen, and Sulphur content. Moisture content was > 5%, Volatile Matter > 50%, Fixed Carbon > 22%, and Heating Value (HHV) 23.74 MJ/kg. Based on its fuel properties, the GMG coal can be classified as a Sub-Bituminous B, non-agglomerating low rank coal (LRC). The GMG coal TPCs – onset, peak, and offset temperatures – were 382.70°C, 454.60°C, and 527.80°C, respectively. The DTG profile revealed four (4) endothermic peaks corresponding to loss of moisture (drying), volatile matter (devolatization), and coke formation. The residual mass Rm was 50.16%, which indicates that higher temperatures above 1000°C are required for the complete pyrolytic decomposition of the GMG coal. In conclusion, the results indicate that the GMG coal is potentially suitable for future utilization in electric power generation and the manufacture of cement and steel.


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2249-2263
Author(s):  
María Alejandra Ramírez-Ramírez ◽  
Artemio Carrillo-Parra ◽  
Faustino Ruíz-Aquino ◽  
Luis Fernando Pintor-Ibarra ◽  
Nicolás González-Ortega ◽  
...  

This research characterized briquettes made with Pinus spp. sawdust without the use of additives. For this purpose, 19 samples of sawdust from different wood industries located in five states of the Mexican Republic were used. The densification process was carried out in a vertical hydraulic piston laboratory briquette machine. The briquettes were made with 40 g of sawdust, at 50 °C, 20 kPa and pressing for 5 min. The results obtained varied as follows: moisture content (4.1% to 7.2%), density (813.9 to 1,014.4 kg/m3), volumetric expansion (7.4% to 37.3%), compressive strength (4.9 to 40.8 N/mm), impact resistance index (46.7% to 200%), ash (0.1% to 1.1%), volatile matter (82.9% to 90.7%), fixed carbon (8.9% to 16.4%), and calorific value (20.5 to 22.8 MJ/kg). The density of the briquettes was within the “acceptable” classification (800 to 1,200 kg/m3). It was observed that, the higher the density, the lower the volumetric expansion, the higher the compressive strength, and the higher the impact resistance index. According to the ash content, the briquettes could achieve international quality. Due to high volatile matter values, rapid combustion of the briquettes with little generation of toxic smoke would be expected. Fixed carbon and calorific value results were acceptable.


2020 ◽  
Vol 190 ◽  
pp. 00030
Author(s):  
Qurrotin Ayunina Maulida Okta Arifianti ◽  
Azmi Alvian Gabriel ◽  
Syarif Hidayatulloh ◽  
Kuntum Khoiro Ummatin

The current research aimed to increase the calorific value of woody cutting waste briquette with paper waste pulp as binder. There were three different binder variation used in this study, they are 5 %, 10 %, and 15 %. To create a briquette, a cylindrical iron mold with diameter of 3.5 cm and height of 3 cm and a hydraulic press with 2 t power were applied. The physical characteristics of the combination woody waste briquette and paper waste pulp, such as moisture content, ash content, volatile matter and carbon fix were examined using proximate analysis. The calorific value of briquetted fuel was tested by bomb calorimeter. The combustion test was performed to determine the combustion characteristic of briquettes, for example initial ignition time, temperature distribution, and combustion process duration. The general result shows that the calorific value of briquette stood in the range of 4 876 kCal kg–1 to 4 993 kCal kg–1. The maximum moisture content of briquette was 5.32 %. The longest burning time was 105 min.


2021 ◽  
Vol 926 (1) ◽  
pp. 012009
Author(s):  
S A C R Darmawan ◽  
A L Sihombing ◽  
D G Cendrawati

Abstract The government has regulated the use of RDF biomass for coal co-firing in power plants. This paper examines biomass (Eichhornia Crassipes and municipal solid waste) characteristics and its potential use as RDF for co-firing in CPP. The method includes the analysis of the composition, supply of raw materials, and biomass characteristics. These results will compare with the coal’s characteristics in CPP. The density of Eichhornia Crassipes in Lake Tondano was 25 kg/m2, with the wet mass of 45,350 tons. The results of the Eichhornia Crassipes sample test for parameters of moisture content, volatile matter, ash content, fix carbon and gross calorific value have a value range of 93%, 5.8-7.1%, 60.21-63.5%, 17.9-22%, 11.4% and 2681-3068 kcal/kg. Amurang CPP uses coal with 4200 kcal/kg calories as much as 1056 tons/day. The co-firing target of 5% requires 52.8 tons of biomass per day. The existing Eichhornia Crassipes biomass in Lake Tondano only supplies the CPP for 62 days. MSW typically has calorific values and moisture with Eichhornia Crassipes biomass, about 3766-4194 kcal/kg and 31.7-87.1%. The use of MSW to cover the lack of Eichhornia Crassipes will ensure the sustainability of the supply of biomass raw materials in the co-firing program at CPP.


Author(s):  
Yusraida Khairani Dalimunthe ◽  
Sugiatmo Kasmungin ◽  
Listiana Satiawati ◽  
Thariq Madani ◽  
Teuku Ananda Rizky

The purpose of this study was to see the best quality of briquettes from the main ingredient of coconut shell waste<br />with various biomass additives to see the calorific value, moisture content, ash content, and volatile matter<br />content of the biomass mixture. Furthermore, further research will be carried out specifically to see the quality of<br />briquettes from a mixture of coconut shell waste and sawdust. The method used in this research is to conduct a<br />literature study of various literature related to briquettes from coconut shell waste mixed with various additives<br />specifically and then look at the best quality briquettes produced from these various pieces of literature. As for<br />what is determined as the control variable of this study is coconut shell waste and as an independent variable,<br />namely coffee skin waste, rice husks, water hyacinth, Bintaro fruit, segon wood sawdust, coconut husk, durian<br />skin, bamboo charcoal, areca nut skin, and leather waste. sago with a certain composition. Furthermore, this<br />paper also describes the stages of making briquettes from coconut shell waste and sawdust for further testing of<br />the calorific value, moisture content, ash content, volatile matter content on a laboratory scale for further<br />research. From various literatures, it was found that the highest calorific value was obtained from a mixture of<br />coconut shell waste and bamboo charcoal with a value of 7110.7288 cal / gr and the lowest calorific value was<br />obtained from a mixture of coconut shell waste and sago shell waste with a value of 114 cal / gr, then for the value<br />The highest water content was obtained from a mixture of coconut shell waste and rice husk with a value of<br />37.70% and the lowest water content value was obtained from a mixture of coconut shell waste 3.80%, then for the<br />highest ash content value was obtained from a mixture of coconut shell waste and coffee skin with a value of<br />20.862% and for the lowest ash content value obtained from a mixture of coconut shell and Bintaro fruit waste,<br />namely 2%, and for the highest volatile matter content value obtained from a mixture of coconut shell and coconut<br />husk waste with a value of 33.45% and for the value of volatile matter levels The lowest was obtained from a<br />mixture of coconut shell waste and sago skin waste with a value of 33 , 45%.


2019 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Ida Febriana ◽  
Zurohaina Zurohaina ◽  
Sahrul Effendy

Charcoal briquettes are smokeless fuels which are a type of solid fuel whose fly substance is made low enough so that the smoke generated on its utilization will not interfere with health. In this study charcoal briquettes were made from bintaro shell waste and betung bamboo using tapioca flour adhesives. This study aims to obtain the best quality sub-bituminous coal briquettes and coal briquettes. In this study the carbonization temperature used was 400ᵒC and the composition of raw materials for bintaro shells and betung bamboo was 50:50, the composition of raw materials for sub-bituminous coal and straw 90:10. The method used in this research is experiment or experimental method, with fuel value collection using ASTM D5865-03 standard. The results obtained from this study are for charcoal briquettes with 4000C carbonization temperature Inherent Moisture value of 1.91%, ash 2.29%, volatile matter 23.79%, fixed carbon 72.01% and calorific value 5878.7 kal / gr, and for coal briquettes obtained value Inherent Moisture 0.52%, ash 4.42%, volatile matter 17.98%, fixed carbon 77.08% and calorific value 7152.6 kal / gr. The fuel value of coal briquettes is greater than that of charcoal briquettes, but the combustion value of charcoal briquettes includes a good calorific value as an alternative energy source, and is in accordance with the SNI standard of 5000 kal / gr, even close to the Japanese standard 6000 cal / gr. Keywords: Bintaro, briquette, calorific value


2020 ◽  
Author(s):  
W.A.R.T.W. Bandara ◽  
Oshadi Ruwanthika Ranasinghe ◽  
Richard Vlosky

Abstract Prosopis juliflora is an invasive plant species rapidly expanding in the Asian and African continents. Invasion of P. juliflora in Bundala Ramsar Wetland (BRW) in Sri Lanka has created a number of biodiversity and conservation issues. This study was conducted to assess the possibility to utilize this invasive plant as a fuel source for local industries. The moisture content, wood density, ash content, volatile matter, fixed carbon content, biomass/ash ration and calorific value of P. juliflora were measured and compared with Leucaena leucocephala, which is a widely used fuelwood source in Sri Lanka and elsewhere. P. juliflora, performed better than L. leucocephala for most of these parameters. Ash content was comparatively higher in P. juliflora than that of L. leucocephala; however, biomass to ash ratio of P. juliflora was significantly lower (at 0.05 level of significance) than that of L. leucocephala, suggesting its suitability as a fuelwood source. Further, the Fuel Value Index (FVI) of P. juliflora (3,276) was slightly lower than that of L. leucocephala (3,336), a non-significant difference. P. juliflora and L. leucocephala reached Fiber Saturation Point values within drying periods of 24 and 27 days, respectively. According to our estimates of energy properties, 1 Kg of P. juliflora could be used to substitute 0.5 L of diesel and furnace oil as well as 5 kWh (5 units) of electricity. As such, we recommend harvesting P. juliflora from BRW as a potential fuelwood energy source for local industries.


Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 444 ◽  
Author(s):  
Samuel Carrasco ◽  
Javier Silva ◽  
Ernesto Pino-Cortés ◽  
Jaime Gómez ◽  
Fidel Vallejo ◽  
...  

The effect of magnesium chloride as an additive of hydrothermal carbonization (HTC) of lignocellulosic biomass (Pinus radiata sawdust) was studied. The HTC tests were carried out at fixed conditions of temperature and residence time of 220 °C and 1 h, respectively, and varying the dose of magnesium chloride in the range 0.0–1.0 g MgCl2/g biomass. The carbonized product (hydrochar) was tested in order to determine its calorific value (HHV) while using PARR 6100 calorimeter, mass yield by gravimetry, elemental analysis using a LECO TruSpec elemental analyzer, volatile matter content, and ash content were obtained by standardized procedures using suitable ovens for it. The results show that using a dose of 0.75 g MgCl2/g biomass results in an impact on the mass yield that was almost equal to change operating conditions from 220 to 270 °C and from 0.5 to 1 h, without additive. Likewise, the calorific value increases by 33% for this additive dose, resulting in an energy yield of 68%, thus generating a solid fuel of prominent characteristics.


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