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02007 A kinetic study of secondary volatile nitrogen release from coal
04
By-products
related to fuels
economical assessment was performed with some considerations given for equipment having already been adopted for LILW treatment in Korea for four treatment strategies with melters selected from a technical assessment. For each strategy, the capital and the operation cost were estimated and the disposal volume was calculated. From the analysis of the disposal costs and the results of the technical assessment, the strategy which incorporated a plasma torch melter for the treatment of non-combustibles and a cold crucible melter for the handling of combustibles was found to be the best. Flue gas cleaning with ammonia reduces SO* 99/02001 emission Emish, G. J. et al. Proc., Annu. Meet. Air Waste Manage. Assoc., 1997, 90, TA30A03, 1-11. The technical and commercial development and basis for the application in North America of wet flue gas desulfurization (FGD) of the AMASOX (i.e. ammonia absorbs sulfur -oxides) process of Krupp Uhde (Germany) employing ammonia reagent is described in this paper. A consideration takes place of the need for accommodating and advantageously addressing the increasing number of applications with high and ultra-high flue-gas concentrations of SOz at the boiler outlet accompanied by significant levels of other pollutants. Key measures in accomplishing this include important process innovations. This calls for the effective use, when applicable, of wet electrostatic precipitator mist-elimination means to gain low/minimumopacity stack plume trail-off in wet scrubber use together with a reduction of air toxics to low concentrations. With cost-effectiveness in electric utility service superior to FGD processes commonly used to date in high-sulfur service, utilization of this technology is expanding. Flue gas desulfurization process using raw meal as 99l92662 absorbent Anon Cim., Betons, P&es, Chaux, 1998, 832, 185-188. (In French) In November 1998, Cementa AB will commission a new desulfurization unit for exhaust gases in the Swedish cement plant Slite in Gotland, based on the limestone washing method using raw meal as absorbent. This unit will produce no residue, as far as the gypsum sludge accruing as waste will be utilized as a resource fed to the cement. Its aim is to reduce the SOz concentration from 1800 to 50 mg/Nm3 dry and the dust concentration from 40 to 10 mg/Nm3 dry. Fly ash hardening inhibitors and method for pre99lO2003 venting hardening of fly ash Muraoka, Y. et al. Jpn. Kokai Tokkyo Koho JP 10 148,322 [98 148,322] (Cl. F23Jl/OO), 2 Jun 1998, Appl. 961320,792, 15 Nov 1996, 3 pp. (In Japanese) Hardening of fly ash is prevented by mixing 100 parts fly ash with lo-30 parts of the inhibitors, which contain 70-95% water and balance monohydric lower alcohols. Heavy metal immobilization method for refuse 99/02004 incinerator fly ash Shinagawa, T. et al. Jpn. Kokai Tokkyo Koho JP 10 165,763 [98 165,763] (Cl. BOlD53/64), 23 Jun 1998, Appl. 961330,993, 11 Dee 1996, 5 pp. (In Japanese) This paper describes the method which comprises blowing a gaseous sulfurizing agent to a flue gas emitted out of a refuse incinerator and reacting heavy metals contained in the fly ash of the flue gas with the gaseous sulfurizing agent to convert the heavy metals into insoluble and stable sulfides. Incinerator fly ash is easily and reliably detoxicated at low cost. Investigation of mercury control in baghouses with 99102005 sorbents Dunham, G. E. et al. Proc., Annu. Meet. Air Waste Manage. Assoc., 1996, 89, wp64b03, 1-18. Clean Air Act Amendment requirements that the US Environmental Protection Agency assess the health risks associated with these emissions mean that the control of mercury emissions for utility power plants may become important. One approach for mercury removal is the injection of sorbents upstream of existing particulate control devices. Since the concentration of mercury in coal combustion flue gas typically ranges from 2 to 10 pg./N m3, accurate measurement of mercury is difficult. Therefore, it is important to establish the confidence intervals of the measurements. A study is being conducted at the University of North Dakota Energy & Environmental Research Center to evaluate the effects of combustion and sorbent parameters on mercury removal in a pilot-scale combustion system. To date, tests have been completed with three coals and two carbon-based sorbents. Each test included four pairs of simultaneous inlet and outlet EPA Method 29 mercury measurements and collection of corresponding baghouse ash samples. This allowed for determination of the mercury removal as well as calculation of the mercury mass balance. The overall experimental variability was calculated using pooled-sample standard deviations. The accumulation of indeterminate errors was calculated to estimate the standard deviation for calculated values such as the mercury removal efficiency. The experimental variability of mercury concentrations was 0.85 pg/m3 at the inlet to the baghouse and 0.97 &m3 at the baghouse outlet. This level of precision translates to a 95% confidence interval of plus or minus 15% removal. The level of precision for the mercury retained in the baghouse ash was 0.60 &m3. Mass balance calculations around the
206
Fuel and Energy Abstracts
May 1999
baghouse resulted in excellent closure. Resolving differences between tests to a finer level will either require an improvement in the experimental precision or an increased number of replicate measurements. 99102006 Ion chromatographic determination of SO* and SO3 in flue gases in pilot plant for removal of SOa and NO, by electron beam treatment Polkowska-Motrenko, H. et al. Chem. Analysis (Warsaw), 1998, 43, (3), 365-373. This paper discusses a method to simultaneously determine SOz and SOz in combustion flue gases from a coal-fired electric plant. SO? and SO3 were collected by absorbing the gases in alkaline aqueous formaldehyde solution and analysing with ion chromatography as S2- and SOa’-. Collection efficiency was nearly 100%. Method precision and accuracy are discussed. The method was used to control the content of SO? and SO? in flue gases from a pilot plant for removal of SOz and NO, by electron beam treatment. 99lO2007 A kinetic study of secondary volatile nitrogen release from coal Man, C. K. et al. Prepr. Symp. Am. Chem. Sot., Div. Fuel Chem., 1998, 43, (4), 1138-1142. Coal chars which are representative of entrained flow combustion and gasification are produced in high-temperature wire mesh pyrolysis. Volatile nitrogen release is a two-step process, i.e. primary and secondary (hightemperature) release. Secondary nitrogen evolution is released as HCN. 99102008 Lignin - a useful bioresource for the production of sorption-active materials Dizhbite, T. et al. Bioresource Technology, 1999, 67, (3), 221-228. The most suitable areas of application of lignin-based sorbents were established by examining the sorption characteristics of acid hydrolysis lignins, commercial by-products of wood conversion to fuel ethanol and their nitrogen-containing derivatives. The results obtained show that the sorption capacity for organic contaminants of an aromatic nature increases significantly as a result of the modification of hydrolysis lignins with quaternary ammonium compounds. The amination of lignin with epoxy amines enhanced its sorption activity towards heavy metals. Aminolignins have a high sorption capacity for bile acids and cholesterol. Sorption properties of nitrogen-containing lignin derivatives are such that they can be proposed for use in the environment-protection field and as enterosorbents. 99lO2009 Manufacture of pellets containing coal ashes and waste tyre rubber for recycling of tires and coal ashes Mizuguchi, H. et al. Jpn. Kokai Tokkyo Koho JP 10 146,527 [98 146,827] (Cl. B29B9/06), 2 Jun 1998, Appl. 961324,566, 20 Nov 1996, 5 pp. (In Japanese) The preparation of the pellets is described. First, the compositions, comprising finely pulverized waste tyre rubber and desulfurization accelerators are kneaded at 300-500°C for plasticization and desulfurization of the rubber. After adding coal ashes or mixtures of coal ashes and thermoplastic polymers to the composition, it is kneaded a second time and then pelletized. Thus, 50 kg/h waste tire, 16.7% dibenzamido-diphenyl disulfide and 1.96% paraffin group-containing processing oil were mixed in a twin-screw extruder at a desulfurization zone temperature -300°C and subsequently mixed in a twin-screw extruder at 200°C after adding 35 kg/h coal ash and 15 kg/h polypropylene to the mixture. The pellets are suitable for mixing with asphalts for pavements or as construction materials, 99lO2010 Method for preparing zeolites from fly ash Janssen-Jurkovicova, M. and Hollman, G. G. PCT Int. Appl. WO 98 26,101 (Cl. C22B7/02), 18 Jun 1998, NL Appl. 1014,729, 9 Dee 1996, 20 pp. (In Dutch) The paper describes a method for preparing zeolite of two different qualities, where a hydroxide solution is added to fly ash and the resulting mixture is separated into fly ash residue and silica extract. The fly ash residue is then mixed with a hydroxide solution to form a reaction mixture which in turn is heated to a temperature of 80-150°C for lo-50 h. The fly ash is held continuously in suspension by stirring and fly ash residues containing the zeolite product are separated from the process water. In one process, aluminium (hydr)oxide is added to the resulting silica extract and the resulting mixture is incubated at an increased temperature to synthesize pure zeolite. In another preferred embodiment of this process, fly ash from waste incineration plants is converted into a zeolite-immobilizer and with the optional addition of required extra aluminium (hydr)oxide and silica. 99lO2011 Method for recovery of fly ashes from flue gas in garbage incineration plant Yoshino, E. Jpn. Kokai Tokkyo Koho JP 10 238,749 (98 238,749] (Cl. F23515/00), 8 Sep 1998, Appl. 97/87,126, 27 Feb 1997, 5 pp. (In Japanese) In this process, the method is carried out by introducing the incineration flue gas into a bag filter via a heat exchanger to collect the fly ashes in the filter and suction of precipitated fly ashes deposited on the passage of the flue gas to be transported to a precipitation chamber below the filter for collection along with the fly ashes from the filter.
By-products
related to fuels
economical assessment was performed with some considerations given for equipment having already been adopted for LILW treatment in Korea for four treatment strategies with melters selected from a technical assessment. For each strategy, the capital and the operation cost were estimated and the disposal volume was calculated. From the analysis of the disposal costs and the results of the technical assessment, the strategy which incorporated a plasma torch melter for the treatment of non-combustibles and a cold crucible melter for the handling of combustibles was found to be the best. Flue gas cleaning with ammonia reduces SO* 99/02001 emission Emish, G. J. et al. Proc., Annu. Meet. Air Waste Manage. Assoc., 1997, 90, TA30A03, 1-11. The technical and commercial development and basis for the application in North America of wet flue gas desulfurization (FGD) of the AMASOX (i.e. ammonia absorbs sulfur -oxides) process of Krupp Uhde (Germany) employing ammonia reagent is described in this paper. A consideration takes place of the need for accommodating and advantageously addressing the increasing number of applications with high and ultra-high flue-gas concentrations of SOz at the boiler outlet accompanied by significant levels of other pollutants. Key measures in accomplishing this include important process innovations. This calls for the effective use, when applicable, of wet electrostatic precipitator mist-elimination means to gain low/minimumopacity stack plume trail-off in wet scrubber use together with a reduction of air toxics to low concentrations. With cost-effectiveness in electric utility service superior to FGD processes commonly used to date in high-sulfur service, utilization of this technology is expanding. Flue gas desulfurization process using raw meal as 99l92662 absorbent Anon Cim., Betons, P&es, Chaux, 1998, 832, 185-188. (In French) In November 1998, Cementa AB will commission a new desulfurization unit for exhaust gases in the Swedish cement plant Slite in Gotland, based on the limestone washing method using raw meal as absorbent. This unit will produce no residue, as far as the gypsum sludge accruing as waste will be utilized as a resource fed to the cement. Its aim is to reduce the SOz concentration from 1800 to 50 mg/Nm3 dry and the dust concentration from 40 to 10 mg/Nm3 dry. Fly ash hardening inhibitors and method for pre99lO2003 venting hardening of fly ash Muraoka, Y. et al. Jpn. Kokai Tokkyo Koho JP 10 148,322 [98 148,322] (Cl. F23Jl/OO), 2 Jun 1998, Appl. 961320,792, 15 Nov 1996, 3 pp. (In Japanese) Hardening of fly ash is prevented by mixing 100 parts fly ash with lo-30 parts of the inhibitors, which contain 70-95% water and balance monohydric lower alcohols. Heavy metal immobilization method for refuse 99/02004 incinerator fly ash Shinagawa, T. et al. Jpn. Kokai Tokkyo Koho JP 10 165,763 [98 165,763] (Cl. BOlD53/64), 23 Jun 1998, Appl. 961330,993, 11 Dee 1996, 5 pp. (In Japanese) This paper describes the method which comprises blowing a gaseous sulfurizing agent to a flue gas emitted out of a refuse incinerator and reacting heavy metals contained in the fly ash of the flue gas with the gaseous sulfurizing agent to convert the heavy metals into insoluble and stable sulfides. Incinerator fly ash is easily and reliably detoxicated at low cost. Investigation of mercury control in baghouses with 99102005 sorbents Dunham, G. E. et al. Proc., Annu. Meet. Air Waste Manage. Assoc., 1996, 89, wp64b03, 1-18. Clean Air Act Amendment requirements that the US Environmental Protection Agency assess the health risks associated with these emissions mean that the control of mercury emissions for utility power plants may become important. One approach for mercury removal is the injection of sorbents upstream of existing particulate control devices. Since the concentration of mercury in coal combustion flue gas typically ranges from 2 to 10 pg./N m3, accurate measurement of mercury is difficult. Therefore, it is important to establish the confidence intervals of the measurements. A study is being conducted at the University of North Dakota Energy & Environmental Research Center to evaluate the effects of combustion and sorbent parameters on mercury removal in a pilot-scale combustion system. To date, tests have been completed with three coals and two carbon-based sorbents. Each test included four pairs of simultaneous inlet and outlet EPA Method 29 mercury measurements and collection of corresponding baghouse ash samples. This allowed for determination of the mercury removal as well as calculation of the mercury mass balance. The overall experimental variability was calculated using pooled-sample standard deviations. The accumulation of indeterminate errors was calculated to estimate the standard deviation for calculated values such as the mercury removal efficiency. The experimental variability of mercury concentrations was 0.85 pg/m3 at the inlet to the baghouse and 0.97 &m3 at the baghouse outlet. This level of precision translates to a 95% confidence interval of plus or minus 15% removal. The level of precision for the mercury retained in the baghouse ash was 0.60 &m3. Mass balance calculations around the
206
Fuel and Energy Abstracts
May 1999
baghouse resulted in excellent closure. Resolving differences between tests to a finer level will either require an improvement in the experimental precision or an increased number of replicate measurements. 99102006 Ion chromatographic determination of SO* and SO3 in flue gases in pilot plant for removal of SOa and NO, by electron beam treatment Polkowska-Motrenko, H. et al. Chem. Analysis (Warsaw), 1998, 43, (3), 365-373. This paper discusses a method to simultaneously determine SOz and SOz in combustion flue gases from a coal-fired electric plant. SO? and SO3 were collected by absorbing the gases in alkaline aqueous formaldehyde solution and analysing with ion chromatography as S2- and SOa’-. Collection efficiency was nearly 100%. Method precision and accuracy are discussed. The method was used to control the content of SO? and SO? in flue gases from a pilot plant for removal of SOz and NO, by electron beam treatment. 99lO2007 A kinetic study of secondary volatile nitrogen release from coal Man, C. K. et al. Prepr. Symp. Am. Chem. Sot., Div. Fuel Chem., 1998, 43, (4), 1138-1142. Coal chars which are representative of entrained flow combustion and gasification are produced in high-temperature wire mesh pyrolysis. Volatile nitrogen release is a two-step process, i.e. primary and secondary (hightemperature) release. Secondary nitrogen evolution is released as HCN. 99102008 Lignin - a useful bioresource for the production of sorption-active materials Dizhbite, T. et al. Bioresource Technology, 1999, 67, (3), 221-228. The most suitable areas of application of lignin-based sorbents were established by examining the sorption characteristics of acid hydrolysis lignins, commercial by-products of wood conversion to fuel ethanol and their nitrogen-containing derivatives. The results obtained show that the sorption capacity for organic contaminants of an aromatic nature increases significantly as a result of the modification of hydrolysis lignins with quaternary ammonium compounds. The amination of lignin with epoxy amines enhanced its sorption activity towards heavy metals. Aminolignins have a high sorption capacity for bile acids and cholesterol. Sorption properties of nitrogen-containing lignin derivatives are such that they can be proposed for use in the environment-protection field and as enterosorbents. 99lO2009 Manufacture of pellets containing coal ashes and waste tyre rubber for recycling of tires and coal ashes Mizuguchi, H. et al. Jpn. Kokai Tokkyo Koho JP 10 146,527 [98 146,827] (Cl. B29B9/06), 2 Jun 1998, Appl. 961324,566, 20 Nov 1996, 5 pp. (In Japanese) The preparation of the pellets is described. First, the compositions, comprising finely pulverized waste tyre rubber and desulfurization accelerators are kneaded at 300-500°C for plasticization and desulfurization of the rubber. After adding coal ashes or mixtures of coal ashes and thermoplastic polymers to the composition, it is kneaded a second time and then pelletized. Thus, 50 kg/h waste tire, 16.7% dibenzamido-diphenyl disulfide and 1.96% paraffin group-containing processing oil were mixed in a twin-screw extruder at a desulfurization zone temperature -300°C and subsequently mixed in a twin-screw extruder at 200°C after adding 35 kg/h coal ash and 15 kg/h polypropylene to the mixture. The pellets are suitable for mixing with asphalts for pavements or as construction materials, 99lO2010 Method for preparing zeolites from fly ash Janssen-Jurkovicova, M. and Hollman, G. G. PCT Int. Appl. WO 98 26,101 (Cl. C22B7/02), 18 Jun 1998, NL Appl. 1014,729, 9 Dee 1996, 20 pp. (In Dutch) The paper describes a method for preparing zeolite of two different qualities, where a hydroxide solution is added to fly ash and the resulting mixture is separated into fly ash residue and silica extract. The fly ash residue is then mixed with a hydroxide solution to form a reaction mixture which in turn is heated to a temperature of 80-150°C for lo-50 h. The fly ash is held continuously in suspension by stirring and fly ash residues containing the zeolite product are separated from the process water. In one process, aluminium (hydr)oxide is added to the resulting silica extract and the resulting mixture is incubated at an increased temperature to synthesize pure zeolite. In another preferred embodiment of this process, fly ash from waste incineration plants is converted into a zeolite-immobilizer and with the optional addition of required extra aluminium (hydr)oxide and silica. 99lO2011 Method for recovery of fly ashes from flue gas in garbage incineration plant Yoshino, E. Jpn. Kokai Tokkyo Koho JP 10 238,749 (98 238,749] (Cl. F23515/00), 8 Sep 1998, Appl. 97/87,126, 27 Feb 1997, 5 pp. (In Japanese) In this process, the method is carried out by introducing the incineration flue gas into a bag filter via a heat exchanger to collect the fly ashes in the filter and suction of precipitated fly ashes deposited on the passage of the flue gas to be transported to a precipitation chamber below the filter for collection along with the fly ashes from the filter.