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03612 Combustion—gasification furnace for low-rank fuels
7 1 Process
00103611 Combustion test of refuse derived fuel in a fluidized bed Piao, G. er ~1. Wusrc Mcmcrgernenl. 2000, 20, (j/6), 443447. Power generation from refuse derived fuel (RDF) is one of the promising technologies for the utilization of municipal solid waste. To understand the combustion behaviour of two kinds of RDF burnt in a fluidized bed incinerator, commercial sized RDF was fed continuously into a 0.3 x 0.3 ma and 2.73 m high bubbling type fluidized bed combustor. Gases such as CO, NO,, SO,, and HCI concentrations in the flue gas from the combustor were detected by a contmuous measurement system. It was found that. for RDFA which IS lower in density and strength than RDF-B, the concentrations of CO in flue gas are high and are strongly affected by the air ratto. When secondary air was injected, the CO concentrations for both RDF-A and RDF-B were decreased. The increase in the air ratio led to an increase of NO, concentration when only primary air was injected at a bed temperature of 1073 K. The addition of secondary air effectively reduced the NO, level for both RDF-A and RDF-B. The temperature where the HCI concentration was the lowest was about 1073 K. Nonetheless the concentrations of HCI were always less than 60 ppm in all experiments. The HCI removal ratio by the calcium compound was higher than 70% even though the bed temperature was higher than 1173K. This indicates that the added calcium compound in the RDFs effectively controlled the HCI emissions. 00/03612 Combustion-gasification furnace for low-rank fuels Makino, K. and Yoshikawa, K. Jpn. Kokai Tokkyo Koho JP 11 209,764 [99 209,764] (Cl. ClOJ3146). 3 Aug 1999, Appl. 1998/10,905, 23 Jan 1998. 5. (In Japanese) A low-rank fuels (e.g. ash- and carbon-containing coal) combustiongasification furnace comprises a reactor for combustion-gasification of fuels and a separation chamber for gravity separation of reaction gas and fused ash connected at the lower part of the reactor. The reactor comprises a combustor at the top of the reactor for oxidation of the fuel with the oxidizing agent, a gas reaction space under the combustor, and a ceramic packed layer in the lower part of the gas reaction space. The fused ash is deposited on the surface of a ceramic packed layer, e.g. on AlaO ball surface and drops as slag, and by contacting the fused ash deposited with the reaction gas the fly ash and unburnt carbon are collected. 00/03613 Dynamic behavior of an AFBC test rig: An experimental study Deoirmenci, E. and Selcuk, N. Proc. Ir~r. Conf Fluid. Bed Cornhtr.sr., 1999, 977-986. The dynamic behaviour of a bubbling 0.3 MWt AFBC test rig fired with a low-quality lignite with a VCM/FC ratio of 7.6 and high ash content (50% on dry basis) was investigated. Transient responses to a step change in fuel feed rate and bed cooling-water flow rate were examined. The corresponding changes in the oxygen and carbon monoxide concentrations at the exit of the freeboard and in the temperatures of bed and freeboard were measured against time. A step increase in the fuel feed rate resulted in a decrease and an increase in oxygen and carbon monoxide concentrations, respectively. Oxygen concentration showed a sudden response while carbon monoxide concentration followed the change in fuel feed rate after an initial lag. The response of bed and freeboard temperatures to the change in fuel feed rate was similar to that of oxygen concentration. A step increase in bed heat withdrawal rate decreased the rate of increase of gas temperatures which, in turn, slowed down the combustion rate which was confirmed by the decrease in carbon monoxide and the increase in oxygen concentrations, respectively. The rate of change of gas temperatures was lower than those of gas concentrations for step changes in both fuel feed rate and bed cooling-water flow rate for the refractory-lined combustor. 00/03614 Energy analysis of blowing of Polish alternative fuels into a blast furnace Ziebik, A. and Stanek, W. Htrrn.-Brad. Hum., 1999. 66, (2). 44-54. (In Polish) Blast furnace management is improved by the blowing of substitute fuels in order to replace a part of coke. At present in Western European steelworks pulverized coal is more usually utilized as a substitute fuel. Multialternative analysis of effects of blowing domestic substitute fuels (pulverized coal, natural gas, coke-oven gas) on energetic indexes of blast-furnace processes is presented. The analysis was carried out by taking into consideration limitations of blast-furnace running (adiabatic temperature) and blast-furnace stove running. Analysis of the direct effects has shown that the blowing of powdered coal is most advantageous for considered substitute fuels. 00103615 Estimation of generation of volatile substances during combustion of solid fuels in small furnaces Prokes, 0. rr al. Uhh-RI&-Geol. Pruzktrm, 1999, 6, (4). 14-18. (In Czech) A generation of volatile substances was experimentally examined in the laboratory during the combustion of coke, coal, brown coal, coal flotation sludges, wood (with or without bark), and paper. Ignition temperature was measured by using a modified Hedden method, and thermogravimetric analysis was performed to estimate generation of the volatile organic substances. The ignition temperature depended on the content of the volatiles and O2 content in the ambient atmosphere. The generation of the volatiles increased with their increased content in the fuels and increasing ignition temperature. Addition of a small amount of flammable organic
heating, power and incineration
(energy applications
in industry)
substances for a decreased ignition temperature of the fuels carbonization for a decreased volatile content were recommended decrease emissions of organic substances.
and to
00103616 Fixed-bed ambient-pressure coal gasification furnaces Sun, B. and Zhang, R. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,130,206 (Cl. ClOJ3/20), 4 Sep 1996, Appl. 95,101,879, 2 Mar 1995. 11. (In Chinese) The furnaces mentioned are equipped with a water jacket, a stoker with a dry distiller, a fire-grate, a fire-grate gearing device, and an ash discharger. The dry distiller is composed of a dry-distillation chamber, dry-distillation tubes, and high-temperature heating tubes, and the length of the heating tube is 5/4-4/3 of the dry-distillation tube. The dry-distillation tubes are made of heat-resistant alloys or heat-resistant heat-conductive ceramics, 00103617 Fluidized-bed gasification furnace with discharge port for fluidizing medium Miyoshi, N. er al. PCT Int. Appl. WO 99 43,985 (Cl. F23Cll/02), 2 Sep 1999, JP Appl. 1998/61,886, 27 Feb 1998. 25. (In Japanese) The fluidized-bed in question is a gasification furnace, e.g. for coal and wastes, capable of quickly discharging unburnt matter contained in fuel along with a fluidizing medium. Specifically, it uses a fluidized bed reaction device, comprising a discharge port for the fluidizing medium disposed in the vicinity of the surface of the fluidized bed and connected with fluidizing medium discharging chutes extended downward below which is a gas blowout device. 00103618 Forced convection and pressure drop in a horizontal triangular-sectional duct with V-grooved (i.e. orthogonal to the mean flow) inner surfaces Leung, C. W. Applied Energy, 2000, 66, (3), 199--21 I. An experimental investigation has been performed to study the forced convection and pressure-drop characteristics fully developed steady turbulent flows in air-cooled, horizontal, equilateral-triangular ducts. These ducts were constructed of duralumin, each of the same axial length and hydraulic diameter. The inner surfaces of each duct were either plane or machined with uniformly-spaced parallel, identical V-grooves. For each tested duct, these grooves had a depth of 1 mm, but were all of the same apex angle, 8, where 0 5 0 < 150”. The uniform separation between the centre lines of two adjacent V-grooves was kept constant at 34 mm. The measurements were performed with the hydraulic diameter-based Reynolds number for the steady-state air flow, ranging from 2800 to 9500. The entire inner wall of the duct was heated uniformly, while its outer surface was thermally insulated. The forced convection was enhanced by the presence of the V-grooves; the greatest forced-convection augmentation being achieved with V-grooves of apex angle B - 17.5”. Non-dimensional expressions for the determination of the steady-state heat transfer coefficient and the Darcy friction-factor for the equilateral triangular ducts, which were fabricated with uniformly-spaced identical V-grooves in their inner surfaces, have been deduced. 00/03619 Heat transfer in circulating fluidized bed combustor Bucak, 0. er crl. Proc. ht. Conf. Fluid. Bed Comhus/., 1999, 643-656. There is broad consensus as to the importance of fluidized bed combustion in utilizing the energy of especially low quality coals. Among various fluidized bed combustion technologies, circulating fluidized beds are preferred as a result of the efforts to get higher combustion efficiencies. The aim of the present research was to investigate the applicability of this technology to Turkish Iignites. To achieve this object a 6.5 m tail pilot cnculating fluidized bed combustor with 155 mm diameter and all the auxiliary equipment was designed, constructed and tested using Seyitomer lignite of 0.9-2.38 mm in size. Heat transfer from the bed to the water cooling jackets was examined to recover the combustion energy. The inside heat transfer coefficient was determined to be around 121 W/m* K for the suspension density of 20-55 kg/m3. The agreement of the experimental findings with theoretical estimations was also checked. In addition, a thermal efficiency of 63% was recovered for the heat in the system. 00103620 Influence of various operating conditions on advanced PFBC with staged combustion Moersch, 0. et al. Proc. Inl. Conf. Fluid. Bed Comhusr., 1999, 61G-622. The focus of the development of PFBC towards advanced or second generation PFBC is on an increase in temperature at the gas turbine inlet to bring forth a substantial improvement of the turbine itself and the overall system performance. Most of such advanced systems described in literature mclude a carbonizer for partial conversion of coal producing a low calorific pressurized syngas and a PFBC burning the remaining char. After hot gas clean-up the syngas and the Oz-rich fuel gas from the PFBC are led to the combustion chamber of the gas turbine. In the proposed staged combustion concept (PFBC-SC), which also aims at raismg the temperatures at the gas turbine inlet, coal is burned sub-stoichiometrically in a pressurized fluidized bed producing a low calorific gas. After hot gas clean-up the gas undergoes post-combustion with pressurized air and enters the gas turbine at approximately 1450 K. The advantages of PFBC-SC over APFBC as described above are the lower investment costs and the simpler process, because no separate gasifier including hot gas cleaning device is needed. At the IVD’s 50 kWth PFBC test facility, experimental investigations were done into sub-stoichiometrical combustion with regard to composition of
Fuel and Energy
Abstracts
November 2000
405
00103611 Combustion test of refuse derived fuel in a fluidized bed Piao, G. er ~1. Wusrc Mcmcrgernenl. 2000, 20, (j/6), 443447. Power generation from refuse derived fuel (RDF) is one of the promising technologies for the utilization of municipal solid waste. To understand the combustion behaviour of two kinds of RDF burnt in a fluidized bed incinerator, commercial sized RDF was fed continuously into a 0.3 x 0.3 ma and 2.73 m high bubbling type fluidized bed combustor. Gases such as CO, NO,, SO,, and HCI concentrations in the flue gas from the combustor were detected by a contmuous measurement system. It was found that. for RDFA which IS lower in density and strength than RDF-B, the concentrations of CO in flue gas are high and are strongly affected by the air ratto. When secondary air was injected, the CO concentrations for both RDF-A and RDF-B were decreased. The increase in the air ratio led to an increase of NO, concentration when only primary air was injected at a bed temperature of 1073 K. The addition of secondary air effectively reduced the NO, level for both RDF-A and RDF-B. The temperature where the HCI concentration was the lowest was about 1073 K. Nonetheless the concentrations of HCI were always less than 60 ppm in all experiments. The HCI removal ratio by the calcium compound was higher than 70% even though the bed temperature was higher than 1173K. This indicates that the added calcium compound in the RDFs effectively controlled the HCI emissions. 00/03612 Combustion-gasification furnace for low-rank fuels Makino, K. and Yoshikawa, K. Jpn. Kokai Tokkyo Koho JP 11 209,764 [99 209,764] (Cl. ClOJ3146). 3 Aug 1999, Appl. 1998/10,905, 23 Jan 1998. 5. (In Japanese) A low-rank fuels (e.g. ash- and carbon-containing coal) combustiongasification furnace comprises a reactor for combustion-gasification of fuels and a separation chamber for gravity separation of reaction gas and fused ash connected at the lower part of the reactor. The reactor comprises a combustor at the top of the reactor for oxidation of the fuel with the oxidizing agent, a gas reaction space under the combustor, and a ceramic packed layer in the lower part of the gas reaction space. The fused ash is deposited on the surface of a ceramic packed layer, e.g. on AlaO ball surface and drops as slag, and by contacting the fused ash deposited with the reaction gas the fly ash and unburnt carbon are collected. 00/03613 Dynamic behavior of an AFBC test rig: An experimental study Deoirmenci, E. and Selcuk, N. Proc. Ir~r. Conf Fluid. Bed Cornhtr.sr., 1999, 977-986. The dynamic behaviour of a bubbling 0.3 MWt AFBC test rig fired with a low-quality lignite with a VCM/FC ratio of 7.6 and high ash content (50% on dry basis) was investigated. Transient responses to a step change in fuel feed rate and bed cooling-water flow rate were examined. The corresponding changes in the oxygen and carbon monoxide concentrations at the exit of the freeboard and in the temperatures of bed and freeboard were measured against time. A step increase in the fuel feed rate resulted in a decrease and an increase in oxygen and carbon monoxide concentrations, respectively. Oxygen concentration showed a sudden response while carbon monoxide concentration followed the change in fuel feed rate after an initial lag. The response of bed and freeboard temperatures to the change in fuel feed rate was similar to that of oxygen concentration. A step increase in bed heat withdrawal rate decreased the rate of increase of gas temperatures which, in turn, slowed down the combustion rate which was confirmed by the decrease in carbon monoxide and the increase in oxygen concentrations, respectively. The rate of change of gas temperatures was lower than those of gas concentrations for step changes in both fuel feed rate and bed cooling-water flow rate for the refractory-lined combustor. 00/03614 Energy analysis of blowing of Polish alternative fuels into a blast furnace Ziebik, A. and Stanek, W. Htrrn.-Brad. Hum., 1999. 66, (2). 44-54. (In Polish) Blast furnace management is improved by the blowing of substitute fuels in order to replace a part of coke. At present in Western European steelworks pulverized coal is more usually utilized as a substitute fuel. Multialternative analysis of effects of blowing domestic substitute fuels (pulverized coal, natural gas, coke-oven gas) on energetic indexes of blast-furnace processes is presented. The analysis was carried out by taking into consideration limitations of blast-furnace running (adiabatic temperature) and blast-furnace stove running. Analysis of the direct effects has shown that the blowing of powdered coal is most advantageous for considered substitute fuels. 00103615 Estimation of generation of volatile substances during combustion of solid fuels in small furnaces Prokes, 0. rr al. Uhh-RI&-Geol. Pruzktrm, 1999, 6, (4). 14-18. (In Czech) A generation of volatile substances was experimentally examined in the laboratory during the combustion of coke, coal, brown coal, coal flotation sludges, wood (with or without bark), and paper. Ignition temperature was measured by using a modified Hedden method, and thermogravimetric analysis was performed to estimate generation of the volatile organic substances. The ignition temperature depended on the content of the volatiles and O2 content in the ambient atmosphere. The generation of the volatiles increased with their increased content in the fuels and increasing ignition temperature. Addition of a small amount of flammable organic
heating, power and incineration
(energy applications
in industry)
substances for a decreased ignition temperature of the fuels carbonization for a decreased volatile content were recommended decrease emissions of organic substances.
and to
00103616 Fixed-bed ambient-pressure coal gasification furnaces Sun, B. and Zhang, R. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,130,206 (Cl. ClOJ3/20), 4 Sep 1996, Appl. 95,101,879, 2 Mar 1995. 11. (In Chinese) The furnaces mentioned are equipped with a water jacket, a stoker with a dry distiller, a fire-grate, a fire-grate gearing device, and an ash discharger. The dry distiller is composed of a dry-distillation chamber, dry-distillation tubes, and high-temperature heating tubes, and the length of the heating tube is 5/4-4/3 of the dry-distillation tube. The dry-distillation tubes are made of heat-resistant alloys or heat-resistant heat-conductive ceramics, 00103617 Fluidized-bed gasification furnace with discharge port for fluidizing medium Miyoshi, N. er al. PCT Int. Appl. WO 99 43,985 (Cl. F23Cll/02), 2 Sep 1999, JP Appl. 1998/61,886, 27 Feb 1998. 25. (In Japanese) The fluidized-bed in question is a gasification furnace, e.g. for coal and wastes, capable of quickly discharging unburnt matter contained in fuel along with a fluidizing medium. Specifically, it uses a fluidized bed reaction device, comprising a discharge port for the fluidizing medium disposed in the vicinity of the surface of the fluidized bed and connected with fluidizing medium discharging chutes extended downward below which is a gas blowout device. 00103618 Forced convection and pressure drop in a horizontal triangular-sectional duct with V-grooved (i.e. orthogonal to the mean flow) inner surfaces Leung, C. W. Applied Energy, 2000, 66, (3), 199--21 I. An experimental investigation has been performed to study the forced convection and pressure-drop characteristics fully developed steady turbulent flows in air-cooled, horizontal, equilateral-triangular ducts. These ducts were constructed of duralumin, each of the same axial length and hydraulic diameter. The inner surfaces of each duct were either plane or machined with uniformly-spaced parallel, identical V-grooves. For each tested duct, these grooves had a depth of 1 mm, but were all of the same apex angle, 8, where 0 5 0 < 150”. The uniform separation between the centre lines of two adjacent V-grooves was kept constant at 34 mm. The measurements were performed with the hydraulic diameter-based Reynolds number for the steady-state air flow, ranging from 2800 to 9500. The entire inner wall of the duct was heated uniformly, while its outer surface was thermally insulated. The forced convection was enhanced by the presence of the V-grooves; the greatest forced-convection augmentation being achieved with V-grooves of apex angle B - 17.5”. Non-dimensional expressions for the determination of the steady-state heat transfer coefficient and the Darcy friction-factor for the equilateral triangular ducts, which were fabricated with uniformly-spaced identical V-grooves in their inner surfaces, have been deduced. 00/03619 Heat transfer in circulating fluidized bed combustor Bucak, 0. er crl. Proc. ht. Conf. Fluid. Bed Comhus/., 1999, 643-656. There is broad consensus as to the importance of fluidized bed combustion in utilizing the energy of especially low quality coals. Among various fluidized bed combustion technologies, circulating fluidized beds are preferred as a result of the efforts to get higher combustion efficiencies. The aim of the present research was to investigate the applicability of this technology to Turkish Iignites. To achieve this object a 6.5 m tail pilot cnculating fluidized bed combustor with 155 mm diameter and all the auxiliary equipment was designed, constructed and tested using Seyitomer lignite of 0.9-2.38 mm in size. Heat transfer from the bed to the water cooling jackets was examined to recover the combustion energy. The inside heat transfer coefficient was determined to be around 121 W/m* K for the suspension density of 20-55 kg/m3. The agreement of the experimental findings with theoretical estimations was also checked. In addition, a thermal efficiency of 63% was recovered for the heat in the system. 00103620 Influence of various operating conditions on advanced PFBC with staged combustion Moersch, 0. et al. Proc. Inl. Conf. Fluid. Bed Comhusr., 1999, 61G-622. The focus of the development of PFBC towards advanced or second generation PFBC is on an increase in temperature at the gas turbine inlet to bring forth a substantial improvement of the turbine itself and the overall system performance. Most of such advanced systems described in literature mclude a carbonizer for partial conversion of coal producing a low calorific pressurized syngas and a PFBC burning the remaining char. After hot gas clean-up the syngas and the Oz-rich fuel gas from the PFBC are led to the combustion chamber of the gas turbine. In the proposed staged combustion concept (PFBC-SC), which also aims at raismg the temperatures at the gas turbine inlet, coal is burned sub-stoichiometrically in a pressurized fluidized bed producing a low calorific gas. After hot gas clean-up the gas undergoes post-combustion with pressurized air and enters the gas turbine at approximately 1450 K. The advantages of PFBC-SC over APFBC as described above are the lower investment costs and the simpler process, because no separate gasifier including hot gas cleaning device is needed. At the IVD’s 50 kWth PFBC test facility, experimental investigations were done into sub-stoichiometrical combustion with regard to composition of
Fuel and Energy
Abstracts
November 2000
405