15
Environment
(pollution, health protection,
safety)
the Joint Coal Board Occupational Health Division indicate that adherence to current maximum exposure levels is sufficient to maintain a health industry work force.
98102481
Respirable coal dust control using surfactants
Tien, J. C. and Kim, J. Appl. Occup. Environ. Hyg., 1997,12, (12), 957-963. With the increasing popularity of highly productive mechanized long-wall sections, dust in areas where miners work has become a major concern. Field applications show that existing dust control technology is more effective in controlling coarser dust particles than finer ones. Other means of controlling small dust particles are needed. The use of surfactants in controlling these fine dust particles has been re-examined on a laboratory scale. Since the effectiveness of surfactants depends on both the type of coal and the type of surfactant used, tests show that non-ionic surfactants generally proved to be the best because of their superior wetting ability of coal through a proper balance between hydrophilic head groups and lipophilic tail groups, and their insensitivity to the water environment. Results also show that this coal wettability can be enhanced through the addition of bases such as NaOH and KOH. The most effective surfactants increased the ability to suppress overall coal dust levels by up to 93% when compared with plain water. More importantly, the best surfactant suppressed fine dust particles up to 125% more effectively than plain water. Sulfur content also influences the effectiveness of different types of coals.
Retrofitting and first operational experiences of two major WTE facilities to meet present and proposed standards of emissions to air
98102482
Heap, B. M. IMechE Conf. Trans., 1997, (4, Engineering for Profit from Waste V), 67-101. The author discusses retrofitting and operational experience of two major waste to energy (WTE) facilities at Coventry and Edmonton, UK, in meeting current and proposed air quality standards. While the primary objectives of retrofit contracts was installation of modern flue gas dry scrubbing equipment, heat recovery was significantly affected by equipment selection. Flue gas emissions and energy savings following retrofit are presented.
Role of methane gas emission in coal outbursts 98102483 Valliappan, S. and Wahua, 2. Eng Geol. Environ., Proc. Int. Symp., 22nd, The 1997. 3. 2549- -2554. Edited by Marinas, P. G., Balkema, Rotterdam, Netherlands. A numerical model of methane gas emission in coal seams and its role in outbursts during mining is introduced. In the first part, an analysis based an the coupled relationship between gas pressure, mass transfer, elastic deformation and porosity of coal has been discussed. In the second part, the elastic work to be done for outbursts to occur has been compared with the released potential energy of gas and coal. The released gas energy due to desorption of methane from the coal matrix to the pores has been identified as the major cause of the outbursts. 98102484
The role of radiation absorption in defining explosibility of coal/rock dust mixtures Llitton, C. D. and Chaiken, R. F. Symp. (Int.) Cornbust., [Proc.], 1996, 26, (l), 1571-1577. The theory and supporting data suggesting that that coal dust explosibility and inerting requirements by powered inhibitors such as rock dust depend upon a material property called the specific absorption, which, in turn, affects the ability of the coal and inert dusts to compete for absorption of the radiant energy from a source of ignition (or propagation) of explosion is presented. An explanation of the experimental observation that, at the lower explosion limit, the product of specific absorption and mass concentration of coal dust is constant for a fixed coal volatility is also given. Theory and data also support the suggestion that a ‘rock dust meter’ (RDM) developed to determine rock dust concentration in a coal/rock dust mixture may also serve directly as an ‘explosibility meter’ to determine the explosion potential of the dust mixture. The RDM is a simple optical device that measures the relative reflectance (at X = 0.94 hm) from bulk mixtures of coal/rock dust. The ratio of the coal to rock dust specific absorption parameters, as determined by the RDM, allows for an a priori prediction of the mass fraction of rock dust necessary to inert a particular coal dust. Of added significance is the finding that, for coal of a fixed volatility, the relative reflectance measured by the RDM at the inert limit is a constant, independent of the particle size of the coal dust and rock dust.
Several-year experience with high-dust lO.O-pitch 98lO2485 ZERONOX catalysts Bonau, H.-W. VGB Tech. Ver. Grosskraftwerksbetr., [Tagungsber.] VGBTB, 1996, Paper V20, 11 pp. (In German) In the treatment of dust-laden coal-fired power plant flue gases, the honeycomb catalyst for selective catalytic reduction of NO, proved to be effective.
Significance of structural and chemical changes in metamorphic coals in the formation of geological discharge hazard
98lO2488
Frolkov, G. D. et al. Bezop. Tr. Prom-sti., 1997, (l), 23-30 (In Russian) Considers the analysis of metamorphic coals with the aim of predicting explosion hazard in mining.
224
Fuel and Energy Abstracts
May 1998
98102487 Solid combustible agent for removing soot and tar from chimneys Boinet, 0. and Faijon, T. Fr. Demande FR 2,749,855 (Cl. ClOL10/06), 19 Dee 1997, Appl. 96/12,365, 10 Ott 1996; 11 pp. (In French) Soot and tar deposits in chimneys can be removed using an agent that consists of a solid combustible cellulosic agent (e.g. sawdust) 20-80 (preferably 25-45) a chemical or catalytic agent (e.g. (NH4)zS04-PzOs mixture) lo-40 (preferably 15-30), and a binder (e.g. paraffin wax) IO-70 wt% (preferably 40-65%). Molten wax is used during preparation, and the resulting mixture is (partially) solidified and extruded to produce blocks, which can be wrapped in (waxed) paper or paperboard, then placed in a furnace and burned to clean the chimney. 98lO2488
Some problems associated with past mining at a mine in the Witbank coalfield, South Africa
Bullock, S. E. T. and Bell, F. G. Environ. Geol., 1997, 33, (l), 61-71. Discusses the environmental problems by mining methods used in the 1930s and 194Os, notably the practices of pillar robbing. Pillar robbing gave rise to collapse of boards and of pillar failure. Primary effects included subsidence, the appearance of tension cracks at the surface and crown-hole development. Secondary effects included spontaneous combustion of coal because of free entry of air associated with an accelerated subsidence due to a reduced strength of pillars by burning, and a marked deterioration of the groundwater quality in this area. Spoil heaps also formed blemishes on the landscape. These contained significant amounts of coal which underwent spontaneous combustion. The deterioration of water quality led to the decimation of vegetation in some areas and the eradication of aquatic flora and fauna in a nearby stream. 98102489
Sources
of strong
primary
acidity
in the
atmosphere
Primerano, P. et al. Atmos. Environ., 1998 (Pub. 1997) 32, (2). 225-230. Produced by the burning of heavy oil, these fly ashes have been identified in this study as carriers of strong primary acidity in the atmosphere in the form of sulfuric acidity and hydrolysable metal ions. This is an acidity which is strong from the moment of its emission and different from common sources of weak acidity, which give rise to strong acidity only after some time in the atmosphere. The oil ash SPA is transmitted to water on impact, resulting in highly acid pH values and high total acidity, as well as significant concentrations of heavy metals. 98102490
The status of oil pollution in the Arabian Gulf by the
end of 1993
Massoud, M. S. et al. Environment International, 1998, 24, (l/2), 11-22. The status of chronic and recent oil pollution levels in the Arabian Gulf were delineated with measurements of total organic carbon (TOC) and concentrations of total petroleum hydrocarbons (TPHS) and trace metals in 40 body- and top-sediment core sub-samples collected in December 1993. These measurements were first compared with those made on sub-samples collected in 1992 from the same sampling stations and correlated with previously identified oil-polluted areas in the region. The similarity of the grain-size distribution and chronic TPH, lead, vanadium and nickel contents of the two sets of samples verifies the stability of chronic pollution levels in the Gulf and implies that bioturbation has a diminishing effect on bottom sediments in the region below 2 cm depth. Differences between the recent TPH contents of the two sets of samples were recorded in three areas, polluted by the Kuwait oil slick. The invalidity of vanadium/nickel ratios and TOC content of bottom sediments as indicators for oil pollution in the Arabian Gulf is emphasized.
Studies of gas outburst mechanism and its dangerous prediction in coal tunnels
98io2491
Lin, B. and Zhou, S. Min. Sci. Technol., Proc. Int. Symp., 1996, 241-244. Edited by Guo, Y. and Golosinski, T. S., Balkema, Rotterdam, The Netherlands. The outburst mechanism in coal tunnels is discussed on the basis of rock and elasto-plastic mechanics. Not only does the outburst depend on ground stress, gas pressure and the strength of the coal body, but on the distress zone in coal tunnels. The theoretical analysis results have led to the design and fabrication of a device to predict outburst to measure the parameter of distress zone in coal tunnels. Using this device it is possible to measure the parameters of the distress zone of coal tunnels in situ and compare the data with predictive parameters measured daily. The research shows that the gas pressure in the coal body of the distress zone and its permeability can be used to forecast the outburst danger and examine the effect of outburst prevention measures. The pressure and permeability were revealed to be sensitive to outburst. 98102492
Study on stability of methane detectlon elements with supported catalysts used in coal mines
Li, X. and Chen, Y. Yunnon Daxue Xuebao, Ziran Kexueban, 1997, 19, (l), 96-99. (In Chinese) Methane is determined with the use of oxidation catalysts supported on A1203. These catalysts, their stability requirement and factors affecting the stability were introduced and methods for improving the stability were discussed.
Environment
(pollution, health protection,
safety)
the Joint Coal Board Occupational Health Division indicate that adherence to current maximum exposure levels is sufficient to maintain a health industry work force.
98102481
Respirable coal dust control using surfactants
Tien, J. C. and Kim, J. Appl. Occup. Environ. Hyg., 1997,12, (12), 957-963. With the increasing popularity of highly productive mechanized long-wall sections, dust in areas where miners work has become a major concern. Field applications show that existing dust control technology is more effective in controlling coarser dust particles than finer ones. Other means of controlling small dust particles are needed. The use of surfactants in controlling these fine dust particles has been re-examined on a laboratory scale. Since the effectiveness of surfactants depends on both the type of coal and the type of surfactant used, tests show that non-ionic surfactants generally proved to be the best because of their superior wetting ability of coal through a proper balance between hydrophilic head groups and lipophilic tail groups, and their insensitivity to the water environment. Results also show that this coal wettability can be enhanced through the addition of bases such as NaOH and KOH. The most effective surfactants increased the ability to suppress overall coal dust levels by up to 93% when compared with plain water. More importantly, the best surfactant suppressed fine dust particles up to 125% more effectively than plain water. Sulfur content also influences the effectiveness of different types of coals.
Retrofitting and first operational experiences of two major WTE facilities to meet present and proposed standards of emissions to air
98102482
Heap, B. M. IMechE Conf. Trans., 1997, (4, Engineering for Profit from Waste V), 67-101. The author discusses retrofitting and operational experience of two major waste to energy (WTE) facilities at Coventry and Edmonton, UK, in meeting current and proposed air quality standards. While the primary objectives of retrofit contracts was installation of modern flue gas dry scrubbing equipment, heat recovery was significantly affected by equipment selection. Flue gas emissions and energy savings following retrofit are presented.
Role of methane gas emission in coal outbursts 98102483 Valliappan, S. and Wahua, 2. Eng Geol. Environ., Proc. Int. Symp., 22nd, The 1997. 3. 2549- -2554. Edited by Marinas, P. G., Balkema, Rotterdam, Netherlands. A numerical model of methane gas emission in coal seams and its role in outbursts during mining is introduced. In the first part, an analysis based an the coupled relationship between gas pressure, mass transfer, elastic deformation and porosity of coal has been discussed. In the second part, the elastic work to be done for outbursts to occur has been compared with the released potential energy of gas and coal. The released gas energy due to desorption of methane from the coal matrix to the pores has been identified as the major cause of the outbursts. 98102484
The role of radiation absorption in defining explosibility of coal/rock dust mixtures Llitton, C. D. and Chaiken, R. F. Symp. (Int.) Cornbust., [Proc.], 1996, 26, (l), 1571-1577. The theory and supporting data suggesting that that coal dust explosibility and inerting requirements by powered inhibitors such as rock dust depend upon a material property called the specific absorption, which, in turn, affects the ability of the coal and inert dusts to compete for absorption of the radiant energy from a source of ignition (or propagation) of explosion is presented. An explanation of the experimental observation that, at the lower explosion limit, the product of specific absorption and mass concentration of coal dust is constant for a fixed coal volatility is also given. Theory and data also support the suggestion that a ‘rock dust meter’ (RDM) developed to determine rock dust concentration in a coal/rock dust mixture may also serve directly as an ‘explosibility meter’ to determine the explosion potential of the dust mixture. The RDM is a simple optical device that measures the relative reflectance (at X = 0.94 hm) from bulk mixtures of coal/rock dust. The ratio of the coal to rock dust specific absorption parameters, as determined by the RDM, allows for an a priori prediction of the mass fraction of rock dust necessary to inert a particular coal dust. Of added significance is the finding that, for coal of a fixed volatility, the relative reflectance measured by the RDM at the inert limit is a constant, independent of the particle size of the coal dust and rock dust.
Several-year experience with high-dust lO.O-pitch 98lO2485 ZERONOX catalysts Bonau, H.-W. VGB Tech. Ver. Grosskraftwerksbetr., [Tagungsber.] VGBTB, 1996, Paper V20, 11 pp. (In German) In the treatment of dust-laden coal-fired power plant flue gases, the honeycomb catalyst for selective catalytic reduction of NO, proved to be effective.
Significance of structural and chemical changes in metamorphic coals in the formation of geological discharge hazard
98lO2488
Frolkov, G. D. et al. Bezop. Tr. Prom-sti., 1997, (l), 23-30 (In Russian) Considers the analysis of metamorphic coals with the aim of predicting explosion hazard in mining.
224
Fuel and Energy Abstracts
May 1998
98102487 Solid combustible agent for removing soot and tar from chimneys Boinet, 0. and Faijon, T. Fr. Demande FR 2,749,855 (Cl. ClOL10/06), 19 Dee 1997, Appl. 96/12,365, 10 Ott 1996; 11 pp. (In French) Soot and tar deposits in chimneys can be removed using an agent that consists of a solid combustible cellulosic agent (e.g. sawdust) 20-80 (preferably 25-45) a chemical or catalytic agent (e.g. (NH4)zS04-PzOs mixture) lo-40 (preferably 15-30), and a binder (e.g. paraffin wax) IO-70 wt% (preferably 40-65%). Molten wax is used during preparation, and the resulting mixture is (partially) solidified and extruded to produce blocks, which can be wrapped in (waxed) paper or paperboard, then placed in a furnace and burned to clean the chimney. 98lO2488
Some problems associated with past mining at a mine in the Witbank coalfield, South Africa
Bullock, S. E. T. and Bell, F. G. Environ. Geol., 1997, 33, (l), 61-71. Discusses the environmental problems by mining methods used in the 1930s and 194Os, notably the practices of pillar robbing. Pillar robbing gave rise to collapse of boards and of pillar failure. Primary effects included subsidence, the appearance of tension cracks at the surface and crown-hole development. Secondary effects included spontaneous combustion of coal because of free entry of air associated with an accelerated subsidence due to a reduced strength of pillars by burning, and a marked deterioration of the groundwater quality in this area. Spoil heaps also formed blemishes on the landscape. These contained significant amounts of coal which underwent spontaneous combustion. The deterioration of water quality led to the decimation of vegetation in some areas and the eradication of aquatic flora and fauna in a nearby stream. 98102489
Sources
of strong
primary
acidity
in the
atmosphere
Primerano, P. et al. Atmos. Environ., 1998 (Pub. 1997) 32, (2). 225-230. Produced by the burning of heavy oil, these fly ashes have been identified in this study as carriers of strong primary acidity in the atmosphere in the form of sulfuric acidity and hydrolysable metal ions. This is an acidity which is strong from the moment of its emission and different from common sources of weak acidity, which give rise to strong acidity only after some time in the atmosphere. The oil ash SPA is transmitted to water on impact, resulting in highly acid pH values and high total acidity, as well as significant concentrations of heavy metals. 98102490
The status of oil pollution in the Arabian Gulf by the
end of 1993
Massoud, M. S. et al. Environment International, 1998, 24, (l/2), 11-22. The status of chronic and recent oil pollution levels in the Arabian Gulf were delineated with measurements of total organic carbon (TOC) and concentrations of total petroleum hydrocarbons (TPHS) and trace metals in 40 body- and top-sediment core sub-samples collected in December 1993. These measurements were first compared with those made on sub-samples collected in 1992 from the same sampling stations and correlated with previously identified oil-polluted areas in the region. The similarity of the grain-size distribution and chronic TPH, lead, vanadium and nickel contents of the two sets of samples verifies the stability of chronic pollution levels in the Gulf and implies that bioturbation has a diminishing effect on bottom sediments in the region below 2 cm depth. Differences between the recent TPH contents of the two sets of samples were recorded in three areas, polluted by the Kuwait oil slick. The invalidity of vanadium/nickel ratios and TOC content of bottom sediments as indicators for oil pollution in the Arabian Gulf is emphasized.
Studies of gas outburst mechanism and its dangerous prediction in coal tunnels
98io2491
Lin, B. and Zhou, S. Min. Sci. Technol., Proc. Int. Symp., 1996, 241-244. Edited by Guo, Y. and Golosinski, T. S., Balkema, Rotterdam, The Netherlands. The outburst mechanism in coal tunnels is discussed on the basis of rock and elasto-plastic mechanics. Not only does the outburst depend on ground stress, gas pressure and the strength of the coal body, but on the distress zone in coal tunnels. The theoretical analysis results have led to the design and fabrication of a device to predict outburst to measure the parameter of distress zone in coal tunnels. Using this device it is possible to measure the parameters of the distress zone of coal tunnels in situ and compare the data with predictive parameters measured daily. The research shows that the gas pressure in the coal body of the distress zone and its permeability can be used to forecast the outburst danger and examine the effect of outburst prevention measures. The pressure and permeability were revealed to be sensitive to outburst. 98102492
Study on stability of methane detectlon elements with supported catalysts used in coal mines
Li, X. and Chen, Y. Yunnon Daxue Xuebao, Ziran Kexueban, 1997, 19, (l), 96-99. (In Chinese) Methane is determined with the use of oxidation catalysts supported on A1203. These catalysts, their stability requirement and factors affecting the stability were introduced and methods for improving the stability were discussed.
