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Heat transfer and bubble characteristics in a fluidized bed with immersed horizontal tube bundle
11 Process heating, power and incineration (energy applications in indu&y)
11 PROCESS HEATING, POWER AND INCINERATION
03/01407 Devekpment and applkation of oompiew industr&dked new m Lnpfuparatlondhlgh~pure CO from CO2 and OS gaeified ooke Zhao, D. et al. Mei Huagong, 2002, (1), 29-32. (In Chinese) An award-winning process for manufacturing synthesis gas from coke or anthracite by using pure 02 and CO2 is described. The process has the advantages of easy industrial application, highly automated control, low operation cost, and being environmentally friendly.
Develo ment of a new external heat exchanger for a circulating fluid Pzed bed boiler
03/01408
Energy applications
in industry
03/01403 Application of temperature fuzzy controller in an Indirect reefstance furnace Radakovic, 2. R. et al. Applied Energy, 2002, 73, (2), 167-182. The paper presents the application results of a fuzzy controller of temperature and its rate of change in indirect resistance chamber furnaces. The method of an initial controller tuning based on the computer simulations is described, where the modelling of the furnace appears as a special problem. Further controller tuning was done based on tests performed on the real furnace. The quality of the finally adopted controller on the real furnace is assessed by its tracking of the desired response, regulation robustness with respect to the presence of load in the furnace, as well as by a comparison with the ideal implementation of the Dahlin algorithm for classic PID control. The experimental part of the work is made using a 5 kW indirect resistance chamber furnace.
O$t~~Oo,spects
of cofirlng natural gas in fluldized bed
Lu, D. Y. and Anthony,
E. J. Proceedings of the International Technical 1, (27). Utilization & Fuel Systems, 2002,
Conference
on
Coal
293-312. As emission regulations for coal-fired boilers continue to follow a downward spiral, it is necessary to develop in-situ methods for reducing FBC emissions still further. The current low price of natural gas makes it possible to modify the FBC process and control its emissions by cofiring natural gas as an additive. Aspects of cofiring natural gas in FBC were conducted in CANMET’s pilot-scale mini-CFBC unit. Various solid fuels, bituminous coals and petroleum coke, were employed in these experiments. This study has shown that fluidized bed combustion chemical is associated with superequilibrium free radical processes, as are high temperature flame systems. The intensity of the free radicals in cofiring natural gas is a benefit of the acceleration of CO oxidation and SO* retention by its own sorbent in coal ash. The enhancement of free radical production is more promising when natural gas is injected into the bottom part of the bed. However, there is no significant impact on nitrogen oxides and the complex processes of nitrogen chemical make it more difficult to predict the emissions of nitrogen oxides. This also implies that heterogeneous reactions are more dominant for NO, emissions and thermal decomposition for N20 emissions. 03/01#S Behavlour of Lakhra (Pakistan) lignite in atmospheric fluldized bed combustion (AFBC) Ali, I. et al. Pakistan Journal of Scientific and Industrial Research, 2002, 45, (2), 79-81.
Results of studies carried out on the combustion of Lakhra lignite in Atmospheric Fluidized Bed Combustor (AFBC) are presented. Investigations cover some of the aspects of combustion including ash and environmental monitoring. AFBC of lignitic coals is safe if sulfur content of coal is less than 4% as there is an optimum limit of addition of CaC03 as sorbent. It is important for the combustor designer to keep in mind about the burning rates, burn-out times and temperature of char particles which may create some problems during heating.
Wang,
Q.
Complex evaluation of properties of blast-furnace
Gainieva, G. R. et ul. Koks i Khimiya, 2002, (6). 10-12. (In Russian) The quality of blast-furnace coke was evaluated and equations for the detection of the ‘technology value’ of coke obtained in 410- and 450mm coke ovens were propbsed. The equations include the following properties of coke: ash, moisture, and S content in coal, strength indexes Mlo, MdO, CSR, and CRI, and indexes of granulometric homogeneity, K, medium diameter of coke pieces, D,,, and gas permeability of bulk coke, G. Indexes UkhIN, Kb, describing physicomechanical properties of coke, and Ilseder number, Ki, were used to evaluated the properties of cokes obtained by dry and wet quenching.
and Proce.vsing,
2003,
42, (4),
An external heat exchanger (EHE) is believed to be a viable way to solve the heat transfer surface arrangement and furnace temperature control to scale-up of circulating fluidized bed (CFB) boilers. A new concept of EHE is developed in this paper. The flow of hot solid particles diverted from the standpipe is controlled by pneumatic (aeration airflows of recycle device or EHE), not the mechanical valve that is in popular use in many CFB boilers. The major feature of this EHE system is that it avoids the use of the mechanical valve that causes heavy erosion and high cost. An in-series connection between the EHE and the recycle device (i.e. the recycle device is on top of the EHE) is proposed. Experiments completed in cold test rigs show that the solid mass flow rate diverted from the standpipe to the EHE or the loop seal may be controlled well by adjusting the fluidizing air of the overflow part of the loop seal, the fluidized air of the fluidized chambers of the EHE and the aeration airflow to the standpipe. In addition, the new EHE has been validated successfully in a 12 MWe CFB boiler.
03/01409 Dynamic simulation of a low-temperature fractlonai distillation cokmn as art of un in gasification combined cycle (IG 8 C) power plan aTIlated Hanke, R. et al. Chemie Ingenieur Tecknik. 2002. 74, (8), 1109-l 113. (In German) A dynamic plant simulation program is presented to simulate a lowtemperature fractional distillation column as a part of an integrated gasification combined cycle (IGCC) power plant. The IGCC technology allowed the utilization of coal and heavy refinery residues as fuel under a higher CO2 reduction potential than conventional power plants. A model for the rectification column was developed and its behaviour under modification of the input enthalpy was studied. The developed model allowed the prediction of the dynamic behaviour of the column under different operation conditions.
OWO1410 Heat transfer and bubble characteristics in a fluidized bed with immersed horizontal tubs bundle Sung, W. K. et al. International
Journal
of Heat and Mass Transfer,
2003, 46, (3). 399409.
The effect of gas velocity on the average and local heat transfer coefficients between a submerged horizontal tube (25.4 mm-OD) and a fluidized bed has been determined in a fluidized-bed-heat-exchanger (0.34x0.50x0.6 m-high) of silica sand particles. The heat transfer coefficients and the properties of bubble and emulsion phases were simultaneously measured at the same location around the tube circumference by thermocouples and an optical probe. The average heat transfer coefficient (huvg) exhibits a maximum value with variation of gas velocity (us). The local heat transfer coefficient (h,) exhibits maximum values at the side of the tube (0”). Bubble frequency &) increases and the emulsion contacting time (te) decreases with increasing [is. The hi increases with increasing fb and decreasing t,. The fb exhibits higher values and teis shorter at the bottom (under each side) than those at the top section of the tube. The t, and bubble fraction (&) have been correlated with Froude number. The predicted h,,, values of small particles based on the packet renewal model and the emulsion contacting characteristics around the tube well accord to the experimental data.
Improving energy use efficiency in Nigeria’s industrial sector: a case study of a beverage plant
03/01411
Akinbami,
W;;406
et 01.ChemicalEngineering
321-335.
2002.
J-F. K. et al. International
18. (2/3/4).
Journal
qf Global Energy, Issues,
239-252.
Industrial energy is a major component of the total energy use in a nation. However, energy is not without a cost in its production, availability, use and even its environmental impact on society. In addition, most of the energy resources are depletable thereby necessitating their sustainable use through energy efficiency improvement programs. In this investigation, an attempt was made to study the energy consumption pattern and management in a beverage plant in Nigeria. The plot of energy intensity and productivity for the period of 1989-1996 showed an increase in growth in energy intensity coupled with a simultaneous productivity declining trend which portrayed inefficiency in the plant’s energy use. A combustion analysis of the boilers in the plant also revealed that it was possible to obtain a fuel saving of about 12% by improving boiler efficiency alone. This would
Fuel and Energy Abstracts
July 2003
249
11 PROCESS HEATING, POWER AND INCINERATION
03/01407 Devekpment and applkation of oompiew industr&dked new m Lnpfuparatlondhlgh~pure CO from CO2 and OS gaeified ooke Zhao, D. et al. Mei Huagong, 2002, (1), 29-32. (In Chinese) An award-winning process for manufacturing synthesis gas from coke or anthracite by using pure 02 and CO2 is described. The process has the advantages of easy industrial application, highly automated control, low operation cost, and being environmentally friendly.
Develo ment of a new external heat exchanger for a circulating fluid Pzed bed boiler
03/01408
Energy applications
in industry
03/01403 Application of temperature fuzzy controller in an Indirect reefstance furnace Radakovic, 2. R. et al. Applied Energy, 2002, 73, (2), 167-182. The paper presents the application results of a fuzzy controller of temperature and its rate of change in indirect resistance chamber furnaces. The method of an initial controller tuning based on the computer simulations is described, where the modelling of the furnace appears as a special problem. Further controller tuning was done based on tests performed on the real furnace. The quality of the finally adopted controller on the real furnace is assessed by its tracking of the desired response, regulation robustness with respect to the presence of load in the furnace, as well as by a comparison with the ideal implementation of the Dahlin algorithm for classic PID control. The experimental part of the work is made using a 5 kW indirect resistance chamber furnace.
O$t~~Oo,spects
of cofirlng natural gas in fluldized bed
Lu, D. Y. and Anthony,
E. J. Proceedings of the International Technical 1, (27). Utilization & Fuel Systems, 2002,
Conference
on
Coal
293-312. As emission regulations for coal-fired boilers continue to follow a downward spiral, it is necessary to develop in-situ methods for reducing FBC emissions still further. The current low price of natural gas makes it possible to modify the FBC process and control its emissions by cofiring natural gas as an additive. Aspects of cofiring natural gas in FBC were conducted in CANMET’s pilot-scale mini-CFBC unit. Various solid fuels, bituminous coals and petroleum coke, were employed in these experiments. This study has shown that fluidized bed combustion chemical is associated with superequilibrium free radical processes, as are high temperature flame systems. The intensity of the free radicals in cofiring natural gas is a benefit of the acceleration of CO oxidation and SO* retention by its own sorbent in coal ash. The enhancement of free radical production is more promising when natural gas is injected into the bottom part of the bed. However, there is no significant impact on nitrogen oxides and the complex processes of nitrogen chemical make it more difficult to predict the emissions of nitrogen oxides. This also implies that heterogeneous reactions are more dominant for NO, emissions and thermal decomposition for N20 emissions. 03/01#S Behavlour of Lakhra (Pakistan) lignite in atmospheric fluldized bed combustion (AFBC) Ali, I. et al. Pakistan Journal of Scientific and Industrial Research, 2002, 45, (2), 79-81.
Results of studies carried out on the combustion of Lakhra lignite in Atmospheric Fluidized Bed Combustor (AFBC) are presented. Investigations cover some of the aspects of combustion including ash and environmental monitoring. AFBC of lignitic coals is safe if sulfur content of coal is less than 4% as there is an optimum limit of addition of CaC03 as sorbent. It is important for the combustor designer to keep in mind about the burning rates, burn-out times and temperature of char particles which may create some problems during heating.
Wang,
Q.
Complex evaluation of properties of blast-furnace
Gainieva, G. R. et ul. Koks i Khimiya, 2002, (6). 10-12. (In Russian) The quality of blast-furnace coke was evaluated and equations for the detection of the ‘technology value’ of coke obtained in 410- and 450mm coke ovens were propbsed. The equations include the following properties of coke: ash, moisture, and S content in coal, strength indexes Mlo, MdO, CSR, and CRI, and indexes of granulometric homogeneity, K, medium diameter of coke pieces, D,,, and gas permeability of bulk coke, G. Indexes UkhIN, Kb, describing physicomechanical properties of coke, and Ilseder number, Ki, were used to evaluated the properties of cokes obtained by dry and wet quenching.
and Proce.vsing,
2003,
42, (4),
An external heat exchanger (EHE) is believed to be a viable way to solve the heat transfer surface arrangement and furnace temperature control to scale-up of circulating fluidized bed (CFB) boilers. A new concept of EHE is developed in this paper. The flow of hot solid particles diverted from the standpipe is controlled by pneumatic (aeration airflows of recycle device or EHE), not the mechanical valve that is in popular use in many CFB boilers. The major feature of this EHE system is that it avoids the use of the mechanical valve that causes heavy erosion and high cost. An in-series connection between the EHE and the recycle device (i.e. the recycle device is on top of the EHE) is proposed. Experiments completed in cold test rigs show that the solid mass flow rate diverted from the standpipe to the EHE or the loop seal may be controlled well by adjusting the fluidizing air of the overflow part of the loop seal, the fluidized air of the fluidized chambers of the EHE and the aeration airflow to the standpipe. In addition, the new EHE has been validated successfully in a 12 MWe CFB boiler.
03/01409 Dynamic simulation of a low-temperature fractlonai distillation cokmn as art of un in gasification combined cycle (IG 8 C) power plan aTIlated Hanke, R. et al. Chemie Ingenieur Tecknik. 2002. 74, (8), 1109-l 113. (In German) A dynamic plant simulation program is presented to simulate a lowtemperature fractional distillation column as a part of an integrated gasification combined cycle (IGCC) power plant. The IGCC technology allowed the utilization of coal and heavy refinery residues as fuel under a higher CO2 reduction potential than conventional power plants. A model for the rectification column was developed and its behaviour under modification of the input enthalpy was studied. The developed model allowed the prediction of the dynamic behaviour of the column under different operation conditions.
OWO1410 Heat transfer and bubble characteristics in a fluidized bed with immersed horizontal tubs bundle Sung, W. K. et al. International
Journal
of Heat and Mass Transfer,
2003, 46, (3). 399409.
The effect of gas velocity on the average and local heat transfer coefficients between a submerged horizontal tube (25.4 mm-OD) and a fluidized bed has been determined in a fluidized-bed-heat-exchanger (0.34x0.50x0.6 m-high) of silica sand particles. The heat transfer coefficients and the properties of bubble and emulsion phases were simultaneously measured at the same location around the tube circumference by thermocouples and an optical probe. The average heat transfer coefficient (huvg) exhibits a maximum value with variation of gas velocity (us). The local heat transfer coefficient (h,) exhibits maximum values at the side of the tube (0”). Bubble frequency &) increases and the emulsion contacting time (te) decreases with increasing [is. The hi increases with increasing fb and decreasing t,. The fb exhibits higher values and teis shorter at the bottom (under each side) than those at the top section of the tube. The t, and bubble fraction (&) have been correlated with Froude number. The predicted h,,, values of small particles based on the packet renewal model and the emulsion contacting characteristics around the tube well accord to the experimental data.
Improving energy use efficiency in Nigeria’s industrial sector: a case study of a beverage plant
03/01411
Akinbami,
W;;406
et 01.ChemicalEngineering
321-335.
2002.
J-F. K. et al. International
18. (2/3/4).
Journal
qf Global Energy, Issues,
239-252.
Industrial energy is a major component of the total energy use in a nation. However, energy is not without a cost in its production, availability, use and even its environmental impact on society. In addition, most of the energy resources are depletable thereby necessitating their sustainable use through energy efficiency improvement programs. In this investigation, an attempt was made to study the energy consumption pattern and management in a beverage plant in Nigeria. The plot of energy intensity and productivity for the period of 1989-1996 showed an increase in growth in energy intensity coupled with a simultaneous productivity declining trend which portrayed inefficiency in the plant’s energy use. A combustion analysis of the boilers in the plant also revealed that it was possible to obtain a fuel saving of about 12% by improving boiler efficiency alone. This would
Fuel and Energy Abstracts
July 2003
249