|首页>> 海外传真 陶瓷新闻 ---陶瓷市场 ---陶瓷新设备、新产品、新工艺---会展信息---网站推荐---统计数据---行业趋势|
首页 海外传真 行业趋势
Glass Forming & Processing: A New Twist to Oxy-Fuel Melting
For a number of years, glass melting technologies have been based on heating glass with the radiant energy from flames fired horizontally above the melt. In this design, the heat transfer efficiency is generally limited by the size of the furnace and the temperature limit of the refractories. Even oxy-fuel combustion, which has been used for more than a decade, is restricted by these heat transfer dynamics.
Recently, however, a new system* was developed that overcomes these limitations. Rather than firing horizontally, the system directs the oxy-fuel flames almost vertically down onto the batch surface at the charging end of the furnace. By modifying conventional oxy-fuel melting technology, the new melting system provides significant improvements in melting rates and/or quality. Firing vertically onto the batch, however, can significantly enhance convective heat transfer. the vertically oriented oxy-fuel flames in the new melting system actually impinge and flow radially over the batch and glass bath.
Significant thinning of boundary layers occurs, leading to intimate contact between the extremely hot flame and the cooler batch and glass bath.
Oxy-fuel flames contain significant concentrations of partially reacted and partially dissociated species. As these species move toward the cool batch surface, they oxidize/recombine and liberate still more energy to the surface, further enhancing the convective heat transfer. This process also increases radiative flux because the burners in the new melting system are designed to produce the majority of the high-temperature combustion reactions near the batch, thereby increasing the radiation to the batch. The increase in total heat transfer to the batch enables increased melting rates. Further, since the burners are installed in the crown rather than the side walls, fewer obstructions affect burner placement. Consequently, the new melting system can supply more energy per square foot of batch surface area without increasing refractory temperatures beyond normal operating limits. The result is a melting system that enables furnaces to melt more glass, and/or higher quality glass, in a furnace of a given size.
中国陶瓷信息资源网 王素媛 译自http://www.ceramicindustry.com