scholarly journals The potential fire and explosion hazards in biomass co-firing with conventional fossil fuels based on data obtained during testing

2018 ◽  
Vol 45 ◽  
pp. 00039 ◽  
Author(s):  
Bozena Kukfisz
Keyword(s):  
Technological Process ◽  
Fossil Fuels ◽  
Coal Dust ◽  
Power Engineering ◽  
Hard Coal ◽  
Fire And Explosion ◽  
Fire And Explosion Hazards ◽  
Experimental Values ◽  
The Given ◽  
A Share

The use of biomass, in particular in power engineering, has created new hazards for mankind and for the environment; including fire and explosion hazards. A description was provided of the use of biomass in power engineering in existing boilers fired by hard coal [1- 10]. Literature and experimental values were outlined for selected parameters of ignitability and explosiveness of selected biomass parameters, and a comparison was presented of the ignitability and the explosiveness parameters for selected biomass dust, a mixture of coal and biomass and for coal dust (according to PN-EN 14034, PN-EN 50281-2-1:2002 and PN-EN 13821:2004). Based on an analysis of the obtained results, it was ascertained that performing analyses of explosive parameters separately, or with a share of coal and biomass, is an incorrect practice due to the fact that in literature on this subject or in the databases of Internet sources, the quoted values are purely indicative in nature and may differ from the conditions actually prevailing in the given technological process during biomass co-firing. A review of the value of the Kst explosiveness factor showed that dust of biomass mixtures may be categorised to dust with strong explosiveness parameters, and their value is higher than coal dust which is comprised within them. Consequently the testing of post-filtering dust is clearly justified.

scholarly journals Nitrogen Oxides Emission Reduction using Sewage Sludge Gasification Gas Reburning Process / Obniżenie Emisji Tlenków Azotu Przy Użyciu Procesu Reburningu Gazem Ze Zgazowania Osadów Ściekowych

2015 ◽  
Vol 22 (1) ◽  
pp. 83-94
Author(s):  
Sebastian Werle
Keyword(s):  
Sewage Sludge ◽  
Nitrogen Oxides ◽  
Fossil Fuels ◽  
Main Product ◽  
Power Engineering ◽  
Hard Coal ◽  
Photochemical Smog ◽  
Reduction Efficiency ◽  
The One ◽  
Small Capacity

Abstract Nitrogen oxides can be formed in various combustion systems. Strategies for the control of NOx emissions in hard coal boilers include the primary (during the combustion) and secondary measures (after combustion). Reburning is the one of the most attractive techniques for reducing NOx emissions. In the last several years, reburning technology has been widely studied but almost only in power engineering big load boilers. Nevertheless, NOx emission is an issue that needs to be considered for small capacity boilers as nitrogen oxides resulting from the combustion of any fossil fuels contribute to the formation of acid rain and photochemical smog, which are significant causes of air pollution. Poland is among the largest coal producing country in Europe. Due to this fact, coal fired boilers are very popular in power engineering and also in the municipal sector. Simultaneously, Poland is characterized by the lack of sewage sludge thermal treatment installation. Gasification is considered as a one of the most perspective method of thermal utilization any carbon-containing material. Syngas, which is the main product of gasification, can be used as a supplemental fuel to reduce the consumption of main fuel in boilers, and it has the potential to reduce NOx emissions. The paper proposes to link those two Polish features so the aim of the work is an experimental investigation of the reburning process of sewage sludge gasification gas in a small capacity domestic coal-fired boiler. The results obtained show how the addition of the reburning fuel influences on NOx reduction efficiency

Hybrid Technology of Hard Coal Mining from Seams Located at Great Depths

2014 ◽  
Vol 59 (3) ◽  
pp. 575-590 ◽  
Author(s):  
Piotr Czaja ◽  
Paweł Kamiński ◽  
Jerzy Klich ◽  
Antoni Tajduś
Keyword(s):  
Coal Mining ◽  
Fossil Fuels ◽  
Coal Gasification ◽  
Economic Effect ◽  
Balance Sheet ◽  
Value Added ◽  
Coal Extraction ◽  
Innovative Technology ◽  
Hard Coal ◽  
Underground Coal Gasification

Abstract Learning to control fire changed the life of man considerably. Learning to convert the energy derived from combustion of coal or hydrocarbons into another type of energy, such as steam pressure or electricity, has put him on the path of scientific and technological revolution, stimulating dynamic development. Since the dawn of time, fossil fuels have been serving as the mankind’s natural reservoir of energy in an increasingly great capacity. A completely incomprehensible refusal to use fossil fuels causes some local populations, who do not possess a comprehensive knowledge of the subject, to protest and even generate social conflicts as an expression of their dislike for the extraction of minerals. Our times are marked by the search for more efficient ways of utilizing fossil fuels by introducing non-conventional technologies of exploiting conventional energy sources. During apartheid, South Africa demonstrated that cheap coal can easily satisfy total demand for liquid and gaseous fuels. In consideration of current high prices of hydrocarbon media (oil and gas), gasification or liquefaction of coal seems to be the innovative technology convergent with contemporary expectations of both energy producers as well as environmentalists. Known mainly from literature reports, underground coal gasification technologies can be brought down to two basic methods: - shaftless method - drilling, in which the gasified seam is uncovered using boreholes drilled from the surface, - shaft method, in which the existing infrastructure of underground mines is used to uncover the seams. This paper presents a hybrid shaft-drilling approach to the acquisition of primary energy carriers (methane and syngas) from coal seams located at great depths. A major advantage of this method is the fact that the use of conventional coal mining technology requires the seams located at great depths to be placed on the off-balance sheet, while the hybrid method of underground gasification enables them to become a source of additional energy for the economy. It should be noted, however, that the shaft-drilling method cannot be considered as an alternative to conventional methods of coal extraction, but rather as a complementary and cheaper way of utilizing resources located almost beyond the technical capabilities of conventional extraction methods due to the associated natural hazards and high costs of combating them. This article presents a completely different approach to the issue of underground coal gasification. Repurposing of the already fully depreciated mining infrastructure for the gasification process may result in a large value added of synthesis gas production and very positive economic effect.

scholarly journals Changes in the Distribution of Temperature in a Coal Deposit and the Composition of Gases Emitted during Its Heating and Cooling

2018 ◽  
Vol 10 (10) ◽  
pp. 3587 ◽  
Author(s):  
Marek Więckowski ◽  
Natalia Howaniec ◽  
Eugene Postnikov ◽  
Mirosław Chorążewski ◽  
Adam Smoliński
Keyword(s):  
Fire Hazard ◽  
Hot Spot ◽  
Measuring System ◽  
Hard Coal ◽  
Coal Deposit ◽  
Hazard Indices ◽  
Heating And Cooling ◽  
Cooling Phase ◽  
Percentage Share ◽  
The Given

This article presents the results of tests conducted on a measuring system for monitoring changes in the distribution of temperature in a coal deposit during the heating and cooling phases, and their correlation with the analysis of the concentration of gases. The tests were conducted on five samples of hard coal collected in deposits mined in Poland. Measurements of the changes in temperature and changes in gas concentration were conducted from the temperature of 35 to 300 °C, for the heating phase, and from 300 to 35 °C, for the cooling phase. The percentage share of coal of given temperatures was calculated. When comparing the percentage share for the same temperature in the hot spot, for the heating and cooling phase, significant differences in the distribution of the given percentages were observed. Changes in gas concentrations during heating and cooling were analyzed and the dynamics of changes in gas concentrations were determined for the coals tested. Changes in the values of fire hazard indices were analyzed. There were significant differences in the concentration of gases and the values of fire hazard indices between the heating and the cooling phase. The application of different criteria to assess coal during heating and cooling was proposed.

scholarly journals Energy Recovery from Sewage Sludge: The Case Study of Croatia

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1927 ◽  
Author(s):  
Dinko Đurđević ◽  
Paolo Blecich ◽  
Željko Jurić
Keyword(s):  
Sewage Sludge ◽  
Energy Recovery ◽  
Fossil Fuels ◽  
Wastewater Treatment Plants ◽  
Energy Generation ◽  
Fuel Oil ◽  
Hard Coal ◽  
Solar Drying ◽  
Sludge Disposal ◽  
Sludge Drying

Croatia produced 21,366 tonnes of dry matter (DM) sewage sludge (SS) in 2016, a quantity expected to surpass 100,000 tonnes DM by 2024. Annual production rates for future wastewater treatment plants (WWTP) in Croatia are estimated at 5.8–7.3 Nm3/people equivalent (PE) for biogas and 20–25 kgDM/PE of sewage sludge. Biogas can be converted into 12–16 kWhel/PE of electricity and 19–24 kWhth/PE of heat, which is sufficient for 30–40% of electrical and 80–100% of thermal autonomy. The WWTP autonomy can be increased using energy recovery from sewage sludge incineration by 60% for electricity and 100% of thermal energy (10–13 kWhel/PE and 30–38 kWhth/PE). However, energy for sewage sludge drying exceeds energy recovery, unless solar drying is performed. The annual solar drying potential is estimated between 450–750 kgDM/m2 of solar drying surface. The lower heating value of dried sewage sludge is 2–3 kWh/kgDM and this energy can be used for assisting sludge drying or for energy generation and supply to WWTPs. Sewage sludge can be considered a renewable energy source and its incineration generates substantially lower greenhouse gases emissions than energy generation from fossil fuels. For the same amount of energy, sewage sludge emits 58% fewer emissions than natural gas and 80% less than hard coal and fuel oil. Moreover, this paper analysed the feasibility of sludge disposal practices by analysing three scenarios (landfilling, co-incineration, and mono-incineration). The analysis revealed that the most cost-effective sewage sludge disposal method is landfilling for 60% and co-incineration for 40% of the observed WWTPs in Croatia. The lowest CO2 emissions are obtained with landfilling and mono-incineration in 53% and 38% of the cases, respectively.

Computer Simulation of Kinematics of Plastic Flow and the Deformed Condition of Metal at Processes Equal-Channel Angular Pressing

2008 ◽  
Vol 584-586 ◽  
pp. 1077-1082
Author(s):  
Aleksandr V. Belevich ◽  
D.M. Babin
Keyword(s):  
Computer Simulation ◽  
Carbon Steel ◽  
Plastic Flow ◽  
Equal Channel Angular Pressing ◽  
Technological Process ◽  
Equal Channel Angular Extrusion ◽  
Theoretical Research ◽  
Angular Pressing ◽  
The Given ◽  
Local Parameters

Object of researches in the given paper is the technological process of obtaining from carbon steel method equal-channel angular extrusion (ECAE) on one pass. The purpose of theoretical research is the working of recomdations on projection of the process with the help of a designed technique of simulation of process ECAE in CAE systems. Calculations were done under variable conditions ECAE over the range changes of parameters: a corner of intersection of channels Ф from 90 up to 150 grades, speed of driving press from 0,05 m/s up to 0,2 m/s, temperature from 20°С up to 600°С. As a result quantitative links of local parameters (stresses, strains and temperature) are established with geometrical and technological ECAE parameters to one separate pass. Regularities of change of parameters to ECAE process of cylindrical preforms in diameter of 20 mm and 30 mm are established (steel 0,15%С), are investigated; character of change of a tension in the instrument and power conditions of the process was studied.

scholarly journals FIRE AND EXPLOSION HAZARDS IN OPERATING THEATRES

1978 ◽  
Vol 50 (7) ◽  
pp. 659-664 ◽  
Author(s):  
M.D. VICKERS ◽  
W.W. MAPLESON
Keyword(s):  
Operating Theatres ◽  
Fire And Explosion ◽  
Fire And Explosion Hazards

Fire and Explosion Hazards Associated with Electrostatic Powder Coating

2020 ◽  
Vol 75 ◽  
pp. 23-36
Author(s):  
Jakub Bielawski
Keyword(s):  
Powder Coating ◽  
Combustible Material ◽  
Dust Layer ◽  
Potential Sources ◽  
Minimum Requirements ◽  
Fire And Explosion ◽  
Fire And Explosion Hazards

This paper presents fire and explosion hazards during electrostatic powder coating, and describes the course of the process as well as the characteristics of powder coating as a combustible material. Potential sources of ignition that could initiate a fire of a dust layer or an explosion of a dust-air mixture have been identified. The minimum requirements and recommendations raising the level of safety in the area of coating installations are presented.

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