Ceramic fiber,a kind of furnace lining material, is widely utilized in industrial furnaces. Fiber blocks can be made into various shapes. They have advantages of low thermal conductivity, low density and light weight ...Ceramic fiber,a kind of furnace lining material, is widely utilized in industrial furnaces. Fiber blocks can be made into various shapes. They have advantages of low thermal conductivity, low density and light weight for the development of industrial furnaces, This paper, taking a continuous annealing furnace as an example, describes the application of ceramic fiber blocks in the furnace and the installation methods. The temperatures of the furnace wall with different linings are analyzed. In the furnace design or the renovation of the existing furnaces, lining with ceramic fiber blocks is the preferred solution.展开更多
Baosteel No.3 blast furnace hearth was divided into tuyere area,taphole area,taphole upper side wall and taphole lower side wall according to different working situations.Through chemical composition analysis,scanning...Baosteel No.3 blast furnace hearth was divided into tuyere area,taphole area,taphole upper side wall and taphole lower side wall according to different working situations.Through chemical composition analysis,scanning electron microscopy,X-ray diffraction,energy dispersive spectrometry and other means,chemical composition and microstructure of different parts of hearth carbon brick were analyzed and markedly different corrosion mechanisms of these areas were found.Zn element in form of ZnO mainly deposited on the hot side of carbon brick.There was no obvious evidence that Zn permeates into carbon bricks and erodes them.Except for taphole area,K,Na,and Fe contents from hot side to cold side gradually rise and fall,resulting in the decrease of apparent porosity,the increase of density and the higher thermal conductivity compared with those of new carbon brick.The higher content of Fe in carbon brick leads to more serious erosion because Fe has greatly changed the physical properties of carbon brick.In the taphole area,the contents of Si and Al present obvious concentration gradient because of the mechanical souring of molten iron and slag.The SiO;and Al;O;particles that have different expansion factors with carbon brick damaged the carbon substrate because of temperature fluctuation.The graphitized carbon found on H4 where is the most serious corrosion site means that the carbon brick ever directly contacts with molten iron.展开更多
In order to expand the study on flow instability of supercritical circulating fluidized bed(CFB) boiler,a new numerical computational model considering the heat storage of the tube wall metal was presented in this pap...In order to expand the study on flow instability of supercritical circulating fluidized bed(CFB) boiler,a new numerical computational model considering the heat storage of the tube wall metal was presented in this paper.The lumped parameter method was proposed for wall temperature calculation and the single channel model was adopted for the analysis of flow instability.Based on the time-domain method,a new numerical computational program suitable for the analysis of flow instability in the water wall of supercritical CFB boiler with annular furnace was established.To verify the code,calculation results were respectively compared with data of commercial software.According to the comparisons,the new code was proved to be reasonable and accurate for practical engineering application in analysis of flow instability.Based on the new program,the flow instability of supercritical CFB boiler with annular furnace was simulated by time-domain method.When 1.2 times heat load disturbance was applied on the loop,results showed that the inlet flow rate,outlet flow rate and wall temperature fluctuated with time eventually remained at constant values,suggesting that the hydrodynamic flow was stable.The results also showed that in the case of considering the heat storage,the flow in the water wall is easier to return to stable state than without considering heat storage.展开更多
文摘Ceramic fiber,a kind of furnace lining material, is widely utilized in industrial furnaces. Fiber blocks can be made into various shapes. They have advantages of low thermal conductivity, low density and light weight for the development of industrial furnaces, This paper, taking a continuous annealing furnace as an example, describes the application of ceramic fiber blocks in the furnace and the installation methods. The temperatures of the furnace wall with different linings are analyzed. In the furnace design or the renovation of the existing furnaces, lining with ceramic fiber blocks is the preferred solution.
文摘Baosteel No.3 blast furnace hearth was divided into tuyere area,taphole area,taphole upper side wall and taphole lower side wall according to different working situations.Through chemical composition analysis,scanning electron microscopy,X-ray diffraction,energy dispersive spectrometry and other means,chemical composition and microstructure of different parts of hearth carbon brick were analyzed and markedly different corrosion mechanisms of these areas were found.Zn element in form of ZnO mainly deposited on the hot side of carbon brick.There was no obvious evidence that Zn permeates into carbon bricks and erodes them.Except for taphole area,K,Na,and Fe contents from hot side to cold side gradually rise and fall,resulting in the decrease of apparent porosity,the increase of density and the higher thermal conductivity compared with those of new carbon brick.The higher content of Fe in carbon brick leads to more serious erosion because Fe has greatly changed the physical properties of carbon brick.In the taphole area,the contents of Si and Al present obvious concentration gradient because of the mechanical souring of molten iron and slag.The SiO;and Al;O;particles that have different expansion factors with carbon brick damaged the carbon substrate because of temperature fluctuation.The graphitized carbon found on H4 where is the most serious corrosion site means that the carbon brick ever directly contacts with molten iron.
基金supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences,Grant No.XDA07030100the National Key Technology R&D Program of China during the 12th Five-Year Plan Period No.2015BAA03B01-01
文摘In order to expand the study on flow instability of supercritical circulating fluidized bed(CFB) boiler,a new numerical computational model considering the heat storage of the tube wall metal was presented in this paper.The lumped parameter method was proposed for wall temperature calculation and the single channel model was adopted for the analysis of flow instability.Based on the time-domain method,a new numerical computational program suitable for the analysis of flow instability in the water wall of supercritical CFB boiler with annular furnace was established.To verify the code,calculation results were respectively compared with data of commercial software.According to the comparisons,the new code was proved to be reasonable and accurate for practical engineering application in analysis of flow instability.Based on the new program,the flow instability of supercritical CFB boiler with annular furnace was simulated by time-domain method.When 1.2 times heat load disturbance was applied on the loop,results showed that the inlet flow rate,outlet flow rate and wall temperature fluctuated with time eventually remained at constant values,suggesting that the hydrodynamic flow was stable.The results also showed that in the case of considering the heat storage,the flow in the water wall is easier to return to stable state than without considering heat storage.
