A comprehensive kinetic model of NO formation during coke combustion in packed-bed in presence of noncombustible particles was developed. The detailed homogeneous gas-phase chemistry (including 102 chemical reactions...A comprehensive kinetic model of NO formation during coke combustion in packed-bed in presence of noncombustible particles was developed. The detailed homogeneous gas-phase chemistry (including 102 chemical reactions), heterogeneous gas-solid chemistry (including 11 reactions) of coke combustion and NO formation, and the heat and mass transfer were taken into account in the present model. The governing equations which are strongly coupled, non-linear and unsteady with 26 unknowns in total, were dispersed into differential equations with the finite differential method. Meanwhile, all the differential equations were numerically solved to give the time-histories and space-distributions oftemperatures of the bed and gas phase as well as the concentrations of all the gaseous species. By comparison, the experimental data were explained well by the calculated results. Based on the kinetic and mathematical model, the effects of O2 content of inlet gas, the initial chemical analysis of coke, bed-temperature and local reductive atmosphere (CO/O2) on NO formation during packed-bed coke combustion were numerically discussed. It was found that coke samples with a higher initial content of [N] and volatile matters, combusted under a suitable O2-containing atmosphere produced less NO emission. The reactions between CO and NO, catalyzed by high temperature surface of coke particles may be responsible for efficient reduction of NO.展开更多
Delayed coking is an important process consumption and light oil yield are important factors used to convert heavy oils to light products. Energy for evaluating the delayed coking process. This paper analyzes the ener...Delayed coking is an important process consumption and light oil yield are important factors used to convert heavy oils to light products. Energy for evaluating the delayed coking process. This paper analyzes the energy consumption and product yields of delayed coking units in China. The average energy consumption shows a decreasing trend in recent years. The energy consumption of different refineries varies greatly, with the average value of the highest energy consumption approximately twice that of the lowest energy consumption. The factors affecting both energy consumption and product yields were analyzed, and correlation models of energy consumption and product yields were established using a quadratic polynomial. The model coefficients were calculated through least square regression of collected industrial data of delayed coking units. Both models showed good calculation accuracy. The average absolute error of the energy consumption model was approximately 85 MJ/t, and that of the product yield model ranged from 1 wt% to 2.3 wt%. The model prediction showed that a large annual processing capacity and high load rate will result in a reduction in energy consumption.展开更多
Bacterial strains in an activated sludge aerobic reactor from a coke wastewater were found to be able to utilize thiocyanate as carbon source when the thiocyanate-containing wastewater was deprived of carbon source. T...Bacterial strains in an activated sludge aerobic reactor from a coke wastewater were found to be able to utilize thiocyanate as carbon source when the thiocyanate-containing wastewater was deprived of carbon source. This study showed that three thiocyanate-oxidizing bacterial strains, Burkholderia sp., Chryseobacterium sp., and Ralstonia sp. were isolated from the activated sludge of a coke wastewater treatment plant as evidenced by the fact that complete decomposition of thiocyanate was achieved either by coculture or individual pure culture. The thiocyanate biodegradation by the coculture occurred with an optimal pH range between 6.5 and 8.5 and an optimal temperature range between 30°C and 40°C. The biodegradation kinetics of thiocyanate was well fitted with the Andrew-Haldane model, which demonstrated a distinct substrate concentration-inhibited bacterial growth pattern. The effects of different types of additional carbon, nitrogen or sulfur sources on thiocyanate biodegradation were also investigated. Analysis of the end-products indicated that thiocyanate degradation by these strains should proceed via two pathways.展开更多
A fractal pore diffusion model of fluids in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot's fractal length-area relation. Bas...A fractal pore diffusion model of fluids in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot's fractal length-area relation. Based on the model, a new formula and its interpretation about the tortuosity of pore structures of a porous medium have been suggested, from which the fractal pore diffusion resistance has been defined. The resistance ascends obviously with the fractal pore dimension and the conversion ratio increasing, especially in the middle-latter period of fluid-solid reactions.展开更多
Based on the detailed analysis of the third coke oven in BaoSteel, a feedbackcontrol strategy of longitudinal temperature and finished carbonization time of coke ovens wasproposed and it was applied to the third coke ...Based on the detailed analysis of the third coke oven in BaoSteel, a feedbackcontrol strategy of longitudinal temperature and finished carbonization time of coke ovens wasproposed and it was applied to the third coke oven in BaoSteel. As a result, the ratio of theinstance that the absolute deviation of the longitudinal temperature is within +- 7 deg C and thefinished carbonization time within +- 10 min is more than 80 percent, having acquired the patentsaving effect of an energy consumption lowered by 2.92 percent. At the same time, it can provide anexample for the same coke ovens inside and outside the nation.展开更多
Based on analyzing the thermal process of a CDQ （coke dry quenching）-Boiler system, the mathematical model for opti-mized operation and control in the CDQ-Boiler system was developed. It includes a mathematical mode...Based on analyzing the thermal process of a CDQ （coke dry quenching）-Boiler system, the mathematical model for opti-mized operation and control in the CDQ-Boiler system was developed. It includes a mathematical model for heat transferring process in the CDQ unit, a mathematical model for heat transferring process in the boiler and a combustion model for circulating gas in the CDQ-Boiler system. The model was verified by field data, then a series of simulations under several typical operating conditions of CDQ-Boiler were carried on, and in turn, the online relation formulas between the productivity and the optimal circulating gas, and the one between the productivity and the optimal second air, were achieved respectively. These relation equations have been success- fully used in a CDQ-Boiler computer control system in the Baosteel, to realize online optimized guide and control, and meanwhile high efficiency in the CDQ-Boiler system has been achieved.展开更多
文摘A comprehensive kinetic model of NO formation during coke combustion in packed-bed in presence of noncombustible particles was developed. The detailed homogeneous gas-phase chemistry (including 102 chemical reactions), heterogeneous gas-solid chemistry (including 11 reactions) of coke combustion and NO formation, and the heat and mass transfer were taken into account in the present model. The governing equations which are strongly coupled, non-linear and unsteady with 26 unknowns in total, were dispersed into differential equations with the finite differential method. Meanwhile, all the differential equations were numerically solved to give the time-histories and space-distributions oftemperatures of the bed and gas phase as well as the concentrations of all the gaseous species. By comparison, the experimental data were explained well by the calculated results. Based on the kinetic and mathematical model, the effects of O2 content of inlet gas, the initial chemical analysis of coke, bed-temperature and local reductive atmosphere (CO/O2) on NO formation during packed-bed coke combustion were numerically discussed. It was found that coke samples with a higher initial content of [N] and volatile matters, combusted under a suitable O2-containing atmosphere produced less NO emission. The reactions between CO and NO, catalyzed by high temperature surface of coke particles may be responsible for efficient reduction of NO.
文摘Delayed coking is an important process consumption and light oil yield are important factors used to convert heavy oils to light products. Energy for evaluating the delayed coking process. This paper analyzes the energy consumption and product yields of delayed coking units in China. The average energy consumption shows a decreasing trend in recent years. The energy consumption of different refineries varies greatly, with the average value of the highest energy consumption approximately twice that of the lowest energy consumption. The factors affecting both energy consumption and product yields were analyzed, and correlation models of energy consumption and product yields were established using a quadratic polynomial. The model coefficients were calculated through least square regression of collected industrial data of delayed coking units. Both models showed good calculation accuracy. The average absolute error of the energy consumption model was approximately 85 MJ/t, and that of the product yield model ranged from 1 wt% to 2.3 wt%. The model prediction showed that a large annual processing capacity and high load rate will result in a reduction in energy consumption.
文摘Bacterial strains in an activated sludge aerobic reactor from a coke wastewater were found to be able to utilize thiocyanate as carbon source when the thiocyanate-containing wastewater was deprived of carbon source. This study showed that three thiocyanate-oxidizing bacterial strains, Burkholderia sp., Chryseobacterium sp., and Ralstonia sp. were isolated from the activated sludge of a coke wastewater treatment plant as evidenced by the fact that complete decomposition of thiocyanate was achieved either by coculture or individual pure culture. The thiocyanate biodegradation by the coculture occurred with an optimal pH range between 6.5 and 8.5 and an optimal temperature range between 30°C and 40°C. The biodegradation kinetics of thiocyanate was well fitted with the Andrew-Haldane model, which demonstrated a distinct substrate concentration-inhibited bacterial growth pattern. The effects of different types of additional carbon, nitrogen or sulfur sources on thiocyanate biodegradation were also investigated. Analysis of the end-products indicated that thiocyanate degradation by these strains should proceed via two pathways.
文摘A fractal pore diffusion model of fluids in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot's fractal length-area relation. Based on the model, a new formula and its interpretation about the tortuosity of pore structures of a porous medium have been suggested, from which the fractal pore diffusion resistance has been defined. The resistance ascends obviously with the fractal pore dimension and the conversion ratio increasing, especially in the middle-latter period of fluid-solid reactions.
文摘Based on the detailed analysis of the third coke oven in BaoSteel, a feedbackcontrol strategy of longitudinal temperature and finished carbonization time of coke ovens wasproposed and it was applied to the third coke oven in BaoSteel. As a result, the ratio of theinstance that the absolute deviation of the longitudinal temperature is within +- 7 deg C and thefinished carbonization time within +- 10 min is more than 80 percent, having acquired the patentsaving effect of an energy consumption lowered by 2.92 percent. At the same time, it can provide anexample for the same coke ovens inside and outside the nation.
文摘Based on analyzing the thermal process of a CDQ （coke dry quenching）-Boiler system, the mathematical model for opti-mized operation and control in the CDQ-Boiler system was developed. It includes a mathematical model for heat transferring process in the CDQ unit, a mathematical model for heat transferring process in the boiler and a combustion model for circulating gas in the CDQ-Boiler system. The model was verified by field data, then a series of simulations under several typical operating conditions of CDQ-Boiler were carried on, and in turn, the online relation formulas between the productivity and the optimal circulating gas, and the one between the productivity and the optimal second air, were achieved respectively. These relation equations have been success- fully used in a CDQ-Boiler computer control system in the Baosteel, to realize online optimized guide and control, and meanwhile high efficiency in the CDQ-Boiler system has been achieved.
