According to the features of melting process of regenerative aluminum melting furnaces, a three-dimensional mathematical model with user-developed melting model, burner reversing and burning capacity model was establi...According to the features of melting process of regenerative aluminum melting furnaces, a three-dimensional mathematical model with user-developed melting model, burner reversing and burning capacity model was established. The numerical simulation of melting process of a regenerative aluminum melting furnace was presented using hybrid programming method of FLUENT UDF and FLUENT scheme based on the heat balance test. Burner effects on melting process of aluminum melting furnaces were investigated by taking optimization regulations into account. The change rules of melting time on influence factors are achieved. Melting time decreases with swirl number, vertical angle of burner, air preheated temperature or natural gas flow; melting time firstly decreases with horizontal angle between burners or air-fuel ratio, then increases; melting time increases with the height of burner.展开更多
Alternative switch combustion mode of air and gas is adopted on the two sides of the regenerative furnace, its temperature is in uncontrolled state in the switching process and the switch period is generally 3 ～ 5 mi...Alternative switch combustion mode of air and gas is adopted on the two sides of the regenerative furnace, its temperature is in uncontrolled state in the switching process and the switch period is generally 3 ～ 5 min. Thus, the conventional bi-cross limited combustion control method is no longer applicable to the object. This paper makes use of neutral network algorithm to adjust the static operating point. On this basis, fuzzy control strategy is used for the furnace temperature control. The actual application result shows that the control strategy is effective to solve the problem of the combustion control for regenerative furnace.展开更多
The authers compared six used criterions of influencing homogeneity of moving airflow in virtue of errors such as variance Q, average square deviation T, homogeneous indices H, inhomogeneous degree W, range R and nonu...The authers compared six used criterions of influencing homogeneity of moving airflow in virtue of errors such as variance Q, average square deviation T, homogeneous indices H, inhomogeneous degree W, range R and nonuniform index S. The auther think that the effects of the errors will be magnified when all these old stnadards were calculated, especially for higher airflow homogeneity, thus the reliability of these norms would De reduced. The authers put forward two new standards to lower influence of error.展开更多
High Temperature Air Combustion(HTAC) based on regenerative theory has been used in developed countries in recent years,it has many advantages such as efficient recovery of waste heat,high temperature preheating air,l...High Temperature Air Combustion(HTAC) based on regenerative theory has been used in developed countries in recent years,it has many advantages such as efficient recovery of waste heat,high temperature preheating air,low pollution discharge,and so on.This Technology can be used in various furnaces in mechanical,petroleum,chemical industry.To rebuild traditional radiant-tube combustion system with HTAC technology has become important.In the transformation process,The biggest difficulty encountered is that the stability of burner combustion and control system. Because the exhaust gas heat is absorbed by the regenerator,exhaust gas discharge can be controlled at a very low temperature to realize maximum waste heat recovery.At the same time,it improves the temperature uniformity and improve the heating intensity.Thermal efficiency of the device can reach more than 80%.And compared to the traditional air preheating,21.55%energy can be saved. Revamping on traditional radiant-tube combustion system is technically feasible,but a lot of problems will be involved since the rebuild work is on the old system,this article discusses on the main problem encountered in rebuild process in site. to optimize temperature control and obtain not so high exhaust gas temperature,digital combustion control system is necessary.This control loop consists of big loop and small loop,Big loop controls the load distribution of all burners in each heating zone.Small loop controls each heating zone burner's burning time. Compared performance of tradition radiant-tube heater with regenerative radiant-tube heater,result that regenerative radiant-tube heater have many advantage in consume fuel.Accordance with experience of replacing tradition radiant-tube heater with regenerative type,give a proposition in combustion control system, pilot burner,flame detection and prevent trouble to rebuild work of CAPL and CGL. It is recommended to use regenerative combustion technology in new annealing Line.Although the investment is 1/3 much more than the traditional combustion system,the energy saving effect is obvious and operating costs decreases.Revamping can be taken step by step according to different heating zones.Although taking a long time,it is safer and it influences the production less. Regenerative combustion burner revamping has become successful.However,the revamping work on different furnaces,particular on continuous annealing furnace with high request for temperature control,need further exploration and research.展开更多
This study compares the regenerative radiant-tube heater with the traditional radiant-tube heater, showing the regenerative radiant-tube heaters have many advantages in fuel consumption. Based on the experience of cha...This study compares the regenerative radiant-tube heater with the traditional radiant-tube heater, showing the regenerative radiant-tube heaters have many advantages in fuel consumption. Based on the experience of changing a heating system with traditional radiant-tube burners to a heating system with regenerative combustion, propositions are given for the combustion control system, pilot burner, flame detection and for trouble prevention in rebuilding the continuous annealing production line（CAPL） and the continuous galvanizing line（CGL）.展开更多
Based on thermal value theory, the aim of this paper is to deduce the theoretical formulas for evaluating the energy effective utilization degree in technological pyrological processes exemplified by metallurgical hea...Based on thermal value theory, the aim of this paper is to deduce the theoretical formulas for evaluating the energy effective utilization degree in technological pyrological processes exemplified by metallurgical heating furnaces. Heat transfer models for continuous heating furnaces, batch-type heating furnaces, and regenerative heating furnaces are established, respectively. By analyzing the movement path of injected infinitesimal heat attached on steel or gas, thermal value equations of continuous, batch-type, and regenerative heating furnaces are derived. Then the influences of such factors as hot charging, gas preheating and intake time of heat on energy effective utilization degree are discussed by thermal value equations. The results show that thermal value rises with hot charging and air preheating for continuous heating furnaces, with shorter intake time when heat is attached on steel or longer intake time when heat is attached on gas for batch-type heating furnaces and that with more heat supply at early heating stage or less at late stage for regenerative heating furnaces.展开更多
基金Project(2009bsxt022)supported by the Dissertation Innovation Foundation of Central South University,ChinaProject(07JJ4016)supported by Natural Science Foundation of Hunan Province,ChinaProject(U0937604)supported by the National Natural Science Foundation of China
文摘According to the features of melting process of regenerative aluminum melting furnaces, a three-dimensional mathematical model with user-developed melting model, burner reversing and burning capacity model was established. The numerical simulation of melting process of a regenerative aluminum melting furnace was presented using hybrid programming method of FLUENT UDF and FLUENT scheme based on the heat balance test. Burner effects on melting process of aluminum melting furnaces were investigated by taking optimization regulations into account. The change rules of melting time on influence factors are achieved. Melting time decreases with swirl number, vertical angle of burner, air preheated temperature or natural gas flow; melting time firstly decreases with horizontal angle between burners or air-fuel ratio, then increases; melting time increases with the height of burner.
文摘Alternative switch combustion mode of air and gas is adopted on the two sides of the regenerative furnace, its temperature is in uncontrolled state in the switching process and the switch period is generally 3 ～ 5 min. Thus, the conventional bi-cross limited combustion control method is no longer applicable to the object. This paper makes use of neutral network algorithm to adjust the static operating point. On this basis, fuzzy control strategy is used for the furnace temperature control. The actual application result shows that the control strategy is effective to solve the problem of the combustion control for regenerative furnace.
文摘The authers compared six used criterions of influencing homogeneity of moving airflow in virtue of errors such as variance Q, average square deviation T, homogeneous indices H, inhomogeneous degree W, range R and nonuniform index S. The auther think that the effects of the errors will be magnified when all these old stnadards were calculated, especially for higher airflow homogeneity, thus the reliability of these norms would De reduced. The authers put forward two new standards to lower influence of error.
文摘High Temperature Air Combustion(HTAC) based on regenerative theory has been used in developed countries in recent years,it has many advantages such as efficient recovery of waste heat,high temperature preheating air,low pollution discharge,and so on.This Technology can be used in various furnaces in mechanical,petroleum,chemical industry.To rebuild traditional radiant-tube combustion system with HTAC technology has become important.In the transformation process,The biggest difficulty encountered is that the stability of burner combustion and control system. Because the exhaust gas heat is absorbed by the regenerator,exhaust gas discharge can be controlled at a very low temperature to realize maximum waste heat recovery.At the same time,it improves the temperature uniformity and improve the heating intensity.Thermal efficiency of the device can reach more than 80%.And compared to the traditional air preheating,21.55%energy can be saved. Revamping on traditional radiant-tube combustion system is technically feasible,but a lot of problems will be involved since the rebuild work is on the old system,this article discusses on the main problem encountered in rebuild process in site. to optimize temperature control and obtain not so high exhaust gas temperature,digital combustion control system is necessary.This control loop consists of big loop and small loop,Big loop controls the load distribution of all burners in each heating zone.Small loop controls each heating zone burner's burning time. Compared performance of tradition radiant-tube heater with regenerative radiant-tube heater,result that regenerative radiant-tube heater have many advantage in consume fuel.Accordance with experience of replacing tradition radiant-tube heater with regenerative type,give a proposition in combustion control system, pilot burner,flame detection and prevent trouble to rebuild work of CAPL and CGL. It is recommended to use regenerative combustion technology in new annealing Line.Although the investment is 1/3 much more than the traditional combustion system,the energy saving effect is obvious and operating costs decreases.Revamping can be taken step by step according to different heating zones.Although taking a long time,it is safer and it influences the production less. Regenerative combustion burner revamping has become successful.However,the revamping work on different furnaces,particular on continuous annealing furnace with high request for temperature control,need further exploration and research.
文摘This study compares the regenerative radiant-tube heater with the traditional radiant-tube heater, showing the regenerative radiant-tube heaters have many advantages in fuel consumption. Based on the experience of changing a heating system with traditional radiant-tube burners to a heating system with regenerative combustion, propositions are given for the combustion control system, pilot burner, flame detection and for trouble prevention in rebuilding the continuous annealing production line（CAPL） and the continuous galvanizing line（CGL）.
文摘Based on thermal value theory, the aim of this paper is to deduce the theoretical formulas for evaluating the energy effective utilization degree in technological pyrological processes exemplified by metallurgical heating furnaces. Heat transfer models for continuous heating furnaces, batch-type heating furnaces, and regenerative heating furnaces are established, respectively. By analyzing the movement path of injected infinitesimal heat attached on steel or gas, thermal value equations of continuous, batch-type, and regenerative heating furnaces are derived. Then the influences of such factors as hot charging, gas preheating and intake time of heat on energy effective utilization degree are discussed by thermal value equations. The results show that thermal value rises with hot charging and air preheating for continuous heating furnaces, with shorter intake time when heat is attached on steel or longer intake time when heat is attached on gas for batch-type heating furnaces and that with more heat supply at early heating stage or less at late stage for regenerative heating furnaces.
