Unit Melter (recuperative)
The furnace is heated by a set of hot air–fuel burners situated along the both furnace sidewalls, burning all the time with air preheat temperatures up to app. 700 °C. The burners are positioned opposite each other.
Low level oxygen enrichment of combustion air is the simplest form of using oxygen in glass melting applications typically applied for furnaces near the end of the campaign for furnaces having either regenerator plugging / partial collapse or a recuperator leakage. The lower volume of offgases gives the posibility to combust additional fuel and optimise the production. The limitation is given by the oxygen compatibility of material downstream from the enrichment point and by the high oxygen volumes neded due to the fact that it goes to all burners. The air burner flames are shortened and the flame temperature is increased.
Oxygen lancing is used in similar situations to enrichment. It gives a possibility to introduce the oxygen additional to the existing air / fuel burner. In most cases it is done by undershot, where it enriches selectively the underside of the conventional flame, thereby concentrating extra heat downward toward the material being heated. In case of oxygen enriched air staging it can be used for optimisation of NOx levels.
The difference between oxyfuel boosting and enrichment/lancing is that in addition to the injection of oxidant there is the addition of fuel and the additional aim is to increase pull rate and/or glass quality. In case of oxyfuel boosting (or partial conversion) are the high efficient oxyfuel burners positioned there where the heat is mostly needed in the furnace – either in the charging end or the hot-spot position.
Hot-spot boosting is typically installed in end-port fired regenerative furnaces. However, it can also be applied to unit melters or recuperative furnaces. It is compatible with all types of glass and typically involves positioning two oxyfuel burners at a furnace’s hot spot. These burners can then be used to enhance glass convection currents, which improve residence time and increase quality. Adding more fuel enables more glass to be melted in the same furnace.
Oxipyr - F
Oxipyr - Flat
Oxipyr - Flex3
Oxipyr - P / P LON
Oxipyr - Advanced regulation
Oxipyr - Basic+, Basic regulation
Oxipyr - 400 regulation