The high chrome bricks specimens were prepared by firing at 1 350,1 450 and 1 550 ℃ in carbon embedded condition and at 1 700 ℃ in air,respectively. Effects of firing atmospheres （carbon embedded and air） on bulk ...The high chrome bricks specimens were prepared by firing at 1 350,1 450 and 1 550 ℃ in carbon embedded condition and at 1 700 ℃ in air,respectively. Effects of firing atmospheres （carbon embedded and air） on bulk density,apparent porosity,cold crushing strength,and slag penetration resistance of high chrome bricks were researched in order to improve physical properties and corrosion resistance of high chrome bricks and to prolong the service life in slagging coal gasifier. The results show that with temperature rising,the apparent porosity of specimens decreases and the bulk density increases; the cold crushing strength of the specimens carbon embedded fired at 1 450 ℃ is the highest,reaching 214 MPa; carbon embedded condition is beneficial to reducing the sintering temperature and improving the microstructure; the specimens carbon embedded fired at 1 450 ℃ perform better slag penetration resistance than the specimens fired at 1 700 ℃ in air.展开更多
The microstructure of high chrome bricks made at different sintering temperature are analyzed by SEM . The results indicate that the sintering temperature of high chromebricks has an optimum range , it is not the high...The microstructure of high chrome bricks made at different sintering temperature are analyzed by SEM . The results indicate that the sintering temperature of high chromebricks has an optimum range , it is not the higher, the better, The high chrome bricks made at this -sintering temperature have the moderate crystal six in the matrix and of dense structure. The closed bonding structure could be obtained between grains and matrix and no crackle occurred.The high chrome bricks with this microstructure have the best dynamic properties.展开更多
To reveal the damage mechanism of high chrome bricks for opposed multi nozzle gasifier with expanded diameter,the chemical composition and the morphology of a used high chrome brick were researched using XRF,SEM and E...To reveal the damage mechanism of high chrome bricks for opposed multi nozzle gasifier with expanded diameter,the chemical composition and the morphology of a used high chrome brick were researched using XRF,SEM and EDS,and the properties of the high chrome bricks were improved by adding ultra fine alumina,alumina-chrome-iron oxide synthetic material with spinel structure,and chromium metal.The results show that(1)the high chrome brick is seriously damaged by the chemical dissolution of chrome as well as the chemical reactions at the slag/brick interface,the slag penetration and the structural spalling;(2)FeO in the slag reacts with Cr_(2)O_(3)in the brick to form a FeCr_(2)O_(4)layer on the particle surface thus leading to spalling;CaO reacts with SiO_(2)and Al2O3 in the brick forming a metamorphic layer of low melting point materials;due to the different thermal expansion coefficients of the metamorphic layer and the original brick,cracks appear and continue to expand and deepen under multiple temperature and pressure fluctuations thus leading to spalling of brick layer;(3)the improved brick has decreased apparent porosity,increased bulk density and compressive strength,and better thermal shock resistance compared with the original brick;after one cycle of on-site application,the furnace lining surface is smooth and flat with little damage,indicating that the improved high chrome bricks basically meet the working condition requirements of the opposed multi nozzle gasifier with expanded diameter,however,the final effects need to be evaluated in detail after the whole furnace service.展开更多
The microstructure and phase composition of high chrome brick used in coal slurry gasifier has been analyzed by means of SEM and Energy Spectrum. The results indicate that the used brick can be divided into different ...The microstructure and phase composition of high chrome brick used in coal slurry gasifier has been analyzed by means of SEM and Energy Spectrum. The results indicate that the used brick can be divided into different zones as slag-adhered zone, reaction zone, penetration zone and unaltered zone. The phase composition and microstructure are different and cracks occurred in different degree at these zones. A dense ring belt was formed with complex spinel (Mg,Fe)(Cr,Al,Fe 2O 4) in the reaction zone near the hot face. The wear mechanism of the brick during its employment has been discussed. It is considered that the reaction and penetration of coal slag and strong reductant bring about the composition change of the brick and destroys its original network inlayed structure and consequently result in its structure spalling and weakening strength, which is the main wear mechanism of the brick and followed by temperature fluctuation and high mechanical impact of flowing fluid with high-speed.展开更多
Research was focused on slag corrosion mechanism of high chrome bricks used for different types of gasifier by comparing the structure of high chrome bricks for petroleum coke gasifier and water-coal slurry gasifier w...Research was focused on slag corrosion mechanism of high chrome bricks used for different types of gasifier by comparing the structure of high chrome bricks for petroleum coke gasifier and water-coal slurry gasifier with slag corroded testing brick and water coal slurry gasifier through Scanning Electron Microscope （SEM） examination and X-ray diffi＇action. Results show that for high chrome brick used for petroleum coke gasifier, corrosion is mainly caused by Cr2O3 in the brick and V2O5 in molten slag and liquid phase generation at low temperature; for high chrome brick used for water-coal slurry gasifier, corrosion is caused by dissolution of Cr2O3 in molten slag and corrosion of ZrO2. For LIRR-HK95 brick, it performs better petroleum coke corrosion resistance than the others due to the optimal composition and structure.展开更多
Wear of the spent high chrome brick in slagging gasifier was studied. The result shows that erosion and spalling are the m, ain wear mechanism of high chrome brick and the CaO content of coal slag is crucial to wear o...Wear of the spent high chrome brick in slagging gasifier was studied. The result shows that erosion and spalling are the m, ain wear mechanism of high chrome brick and the CaO content of coal slag is crucial to wear of high chrome brick.展开更多
文摘The high chrome bricks specimens were prepared by firing at 1 350,1 450 and 1 550 ℃ in carbon embedded condition and at 1 700 ℃ in air,respectively. Effects of firing atmospheres （carbon embedded and air） on bulk density,apparent porosity,cold crushing strength,and slag penetration resistance of high chrome bricks were researched in order to improve physical properties and corrosion resistance of high chrome bricks and to prolong the service life in slagging coal gasifier. The results show that with temperature rising,the apparent porosity of specimens decreases and the bulk density increases; the cold crushing strength of the specimens carbon embedded fired at 1 450 ℃ is the highest,reaching 214 MPa; carbon embedded condition is beneficial to reducing the sintering temperature and improving the microstructure; the specimens carbon embedded fired at 1 450 ℃ perform better slag penetration resistance than the specimens fired at 1 700 ℃ in air.
文摘The microstructure of high chrome bricks made at different sintering temperature are analyzed by SEM . The results indicate that the sintering temperature of high chromebricks has an optimum range , it is not the higher, the better, The high chrome bricks made at this -sintering temperature have the moderate crystal six in the matrix and of dense structure. The closed bonding structure could be obtained between grains and matrix and no crackle occurred.The high chrome bricks with this microstructure have the best dynamic properties.
文摘To reveal the damage mechanism of high chrome bricks for opposed multi nozzle gasifier with expanded diameter,the chemical composition and the morphology of a used high chrome brick were researched using XRF,SEM and EDS,and the properties of the high chrome bricks were improved by adding ultra fine alumina,alumina-chrome-iron oxide synthetic material with spinel structure,and chromium metal.The results show that(1)the high chrome brick is seriously damaged by the chemical dissolution of chrome as well as the chemical reactions at the slag/brick interface,the slag penetration and the structural spalling;(2)FeO in the slag reacts with Cr_(2)O_(3)in the brick to form a FeCr_(2)O_(4)layer on the particle surface thus leading to spalling;CaO reacts with SiO_(2)and Al2O3 in the brick forming a metamorphic layer of low melting point materials;due to the different thermal expansion coefficients of the metamorphic layer and the original brick,cracks appear and continue to expand and deepen under multiple temperature and pressure fluctuations thus leading to spalling of brick layer;(3)the improved brick has decreased apparent porosity,increased bulk density and compressive strength,and better thermal shock resistance compared with the original brick;after one cycle of on-site application,the furnace lining surface is smooth and flat with little damage,indicating that the improved high chrome bricks basically meet the working condition requirements of the opposed multi nozzle gasifier with expanded diameter,however,the final effects need to be evaluated in detail after the whole furnace service.
文摘The microstructure and phase composition of high chrome brick used in coal slurry gasifier has been analyzed by means of SEM and Energy Spectrum. The results indicate that the used brick can be divided into different zones as slag-adhered zone, reaction zone, penetration zone and unaltered zone. The phase composition and microstructure are different and cracks occurred in different degree at these zones. A dense ring belt was formed with complex spinel (Mg,Fe)(Cr,Al,Fe 2O 4) in the reaction zone near the hot face. The wear mechanism of the brick during its employment has been discussed. It is considered that the reaction and penetration of coal slag and strong reductant bring about the composition change of the brick and destroys its original network inlayed structure and consequently result in its structure spalling and weakening strength, which is the main wear mechanism of the brick and followed by temperature fluctuation and high mechanical impact of flowing fluid with high-speed.
文摘Research was focused on slag corrosion mechanism of high chrome bricks used for different types of gasifier by comparing the structure of high chrome bricks for petroleum coke gasifier and water-coal slurry gasifier with slag corroded testing brick and water coal slurry gasifier through Scanning Electron Microscope （SEM） examination and X-ray diffi＇action. Results show that for high chrome brick used for petroleum coke gasifier, corrosion is mainly caused by Cr2O3 in the brick and V2O5 in molten slag and liquid phase generation at low temperature; for high chrome brick used for water-coal slurry gasifier, corrosion is caused by dissolution of Cr2O3 in molten slag and corrosion of ZrO2. For LIRR-HK95 brick, it performs better petroleum coke corrosion resistance than the others due to the optimal composition and structure.
文摘Wear of the spent high chrome brick in slagging gasifier was studied. The result shows that erosion and spalling are the m, ain wear mechanism of high chrome brick and the CaO content of coal slag is crucial to wear of high chrome brick.
