| OCR Text |
Show Wider industrial acceptance of oxy-fuel firing will require resolution of a number of limitations in current application of the technology. The most important limiting factors relative to glass melting are: • a non-luminous flame when fired into the hot furnace, which leads to decreased radiative heat transfer to the load; • a non-uniform temperature distribution in the furnace, which leads to the development of hot spots and reduces crown refractory life; • a non-uniform heat flux distribution to the load, which may affect the quality of the glass. The limitations of current oxy-fuel firing technology can be overcome with an improved burner system offering a more luminous flame, a lower average flame temperature, and more uniform temperature and heat transfer profiles. IGT has patented a High Luminosity Burner concept that addresses all these issues and provides the following: • Higher heat transfer to the load. Cracking of natural gas generates soot particles which increase the flame luminosity and provide higher heat transfer as well as higher process and energy efficiency. • Lower flame temperature and exhaust gas temperature. Greater heat transfer from the flame produces a radiative cooling effect on the flame. • More uniform heat transfer. Staged combustion increases flame coverage which produces a more uniform heat flux and temperature profile. • Lower N O x yield. The lower flame temperature and lower natural gas consumption lead to less N O x production. Several methods can be used to improve the energy efficiency from oxy-fuel firing. The High Luminosity Burner improves energy efficiency by increasing the radiative heat transfer from the flame to the load. In this novel combustion concept, soot precursors and then soot particles are generated by reforming (cracking) of natural gas under controlled conditions. Subsequently, the soot particles, when burned, increase the flame luminosity. This increased flame luminosity (brightness) leads to an elevated heat transfer rate to the load. Flame length is increased, and at the same time, radiative cooling reduces the flame temperature. As a result, the heat transfer uniformity is increased and N O x emissions are significantly reduced. The new burner system can be installed on new furnaces and can easily be retrofitted to existing oxy-gas 2 |
