Process of using a submerged combustion melter to produce hollow glass fiber or solid glass fiber having entrained bubbles, and burners and systems to make such fibers

Abstract

Processes and systems for producing glass fibers having regions devoid of glass using submerged combustion melters, including feeding a vitrifiable feed material into a feed inlet of a melting zone of a melter vessel, and heating the vitrifiable material with at least one burner directing combustion products of an oxidant and a first fuel into the melting zone under a level of the molten material in the zone. One or more of the burners is configured to impart heat and turbulence to the molten material, producing a turbulent molten material comprising a plurality of bubbles suspended in the molten material, the bubbles comprising at least some of the combustion products, and optionally other gas species introduced by the burners. The molten material and bubbles are drawn through a bushing fluidly connected to a forehearth to produce a glass fiber comprising a plurality of interior regions substantially devoid of glass.

What is claimed is: 
     
         1 . A process of making insulating fibers comprising:
 a) feeding one or more feed materials selected from recycled glass or “cullet”, various waste materials of varying glass content (such as fiberglass batting or even loose fibers), scrap in the form of glass fiber mat and/or insulation having high organic binder content, and mixtures of two or more of these, into a melting zone of a melter vessel comprising a melter exit structure for discharging molten material formed in the melting zone;   b) heating the feed materials with at least one burner directing combustion products of an oxidant and a first fuel into the melting zone under a level of the molten material in the melting zone, one or more of the burners configured to impart heat and turbulence to at least some of the molten material in the melting zone, producing a turbulent molten material comprising a plurality of bubbles suspended in the molten material, the bubbles comprising at least some of the combustion products;   c) discharging the molten material comprising bubbles from the melter vessel through the melter exit structure into a forehearth; and   d) drawing the molten material comprising bubbles through a bushing fluidly connected to the forehearth to produce hollow insulating fibers, or insulating fibers having regions substantially devoid of glass.   
     
     
         2 . The process of  claim 1  wherein the forehearth has a plurality of bushings producing the hollow insulating fibers, or insulating fibers having regions substantially devoid of glass, the insulating fibers having same outside diameter, the process comprising controlling flow of the molten material comprising bubbles through the forehearth and bushings so that the insulating fibers produced through the bushings are substantially consistent in volume of regions devoid of glass. 
     
     
         3 . The process of  claim 2  wherein the controlling comprises inclining the forehearth at an angle to horizontal of no more than about 30 degrees to horizontal, the angle causing a distal end of the forehearth furthest from the melter exit structure to be raised above a horizontal plane, while a proximal end of the forehearth remains at a level equal to that of the melter exit. 
     
     
         4 . The process of  claim 2  wherein the forehearth is substantially horizontal, and the controlling comprises the bushings drawing off the molten material comprising bubbles in a configuration where a bushing most proximal to the melter exit structure draws at a lowest level in the forehearth and succeeding bushings draw molten material comprising bubbles at progressively higher levels in the forehearth. 
     
     
         5 . The process of  claim 1  comprising controlling composition of the turbulent molten material and the bubbles suspended in the molten material by adjusting one or more of the burners. 
     
     
         6 . The process of  claim 5  comprising adjusting one or more parameters selected from the group consisting of composition of the first fuel, composition of the oxidant, composition of a third fluid injected through at least one of the burners, flow rate of the first fuel, flow rate of the oxidant, and flow rate of the third fluid. 
     
     
         7 . The process of  claim 6  wherein the feeding of the third fluid is selected from the group consisting of feeding a composition comprising a second fuel, feeding a second oxidant, feeding a fluid other than a fuel or an oxidant, and combinations thereof. 
     
     
         8 . The process of  claim 1  comprising adjusting one or more of temperature of the molten material, flow rate of one or more of the feed materials, molten glass discharge rate, and degree of turbulence of the molten material to achieve an average bubble diameter in the molten material that is less than a diameter of the hollow insulating fibers, or insulating fibers having regions substantially devoid of glass. 
     
     
         9 . The process of  claim 1  comprising controlling volume of the regions substantially devoid of glass by adjusting volume of individual bubbles in the molten material. 
     
     
         10 . The process of  claim 1  comprising forming an insulation product comprising the hollow insulating fibers, or insulating fibers having regions substantially devoid of glass. 
     
     
         11 . A process of making insulating fibers comprising:
 a) feeding one or more feed materials selected from recycled glass or “cullet”, various waste materials of varying glass content (such as fiberglass batting or even loose fibers), scrap in the form of glass fiber mat and/or insulation having high organic binder content, and mixtures of two or more of these, into a feed inlet of a melting zone of a melter vessel comprising a melter exit structure for discharging molten material formed in the melting zone;   b) heating the one or more feed materials with at least one burner directing combustion products of an oxidant and a first fuel into the melting zone under a level of the molten material in the zone, one or more of the burners configured to impart heat and turbulence to at least some of the molten material in the melting zone, producing a turbulent molten material comprising a plurality of bubbles suspended in the molten material, the bubbles comprising at least some of the combustion products;   c) discharging the molten material comprising bubbles from the melter vessel through the melter exit structure into a forehearth;   d) drawing the molten material comprising bubbles through a plurality of bushings producing hollow insulating fibers, or insulating fibers having regions substantially devoid of glass, each comprising a plurality of interior regions devoid of glass, the fibers having substantially same outside diameter; and   e) controlling flow of the molten material comprising bubbles through the forehearth and bushings so that fibers produced through the bushings are substantially consistent in volume of regions devoid of glass.   
     
     
         12 . The process of  claim 11  wherein the controlling comprises inclining forehearth at an angle to horizontal of no more than about 30 degrees, the angle causing a distal end of the forehearth to be raised above a horizontal plane, while a proximal end of the forehearth remains at a level equal to that of the melter exit. 
     
     
         13 . The process of  claim 11  wherein the controlling comprises the bushings drawing off the molten material comprising bubbles in a configuration where a bushing most proximal to the melter exit structure draws at a lowest level in the forehearth and succeeding bushings draw molten material comprising bubbles at succeeding higher levels in the forehearth. 
     
     
         14 . The process of  claim 11  comprising controlling composition of the molten material by adjusting one or more of the burners. 
     
     
         15 . The process of  claim 14  comprising adjusting one or more parameters selected from the group consisting of composition of the first fuel, composition of the oxidant, composition of a third fluid injected through at least one of the burners, flow rate of the first fuel, flow rate of the oxidant, and flow rate of the third fluid. 
     
     
         16 . The process of  claim 15  wherein the feeding of the third fluid is selected from the group consisting of feeding a composition comprising a second fuel, feeding a second oxidant, feeding a fluid other than a fuel or an oxidant, and combinations thereof. 
     
     
         17 . A system for making insulating fibers comprising:
 a) a melter vessel comprising a turbulent melting zone and one or more burners, at least one of which is positioned to direct combustion products into the turbulent melting zone under a level of turbulent molten material in the turbulent melting zone;   b) a forehearth fluidly connected to the melter vessel without any intervening channel or component, the forehearth comprising a plurality of bushings configured to produce hollow insulating fibers, or insulating fibers having regions substantially devoid of glass, each comprising a plurality of interior regions substantially devoid of glass, the fibers having substantially same outside diameter.   
     
     
         18 . The system of  claim 17  wherein at least one of the burners comprises:
 a first conduit comprising a first end, a second end, a longitudinal bore having a longitudinal axis, and an external surface; 
 a second conduit substantially concentric with the first conduit, the second conduit comprising a first end, a second end, and an internal surface; 
 the first and second conduits configured to form a primary annulus between the external surface of the first conduit and the internal surface of the second conduit; 
 a third substantially concentric conduit comprising a first end, a second end, and an internal surface, the internal surface of the third conduit forming, with an exterior surface of the second conduit, a secondary annulus external to the primary annulus; 
 one or more alternate gas tubes extending substantially longitudinally through one of the primary and the secondary annuli and comprising distal ends terminating in ports near the first end of the second conduit; and 
 one or more secondary fuel tubes extending substantially longitudinally through one of the primary and secondary annuli and comprising distal ends positioned near the first ends of the first and second conduits. 
 
     
     
         19 . The system of  claim 17  wherein the forehearth is inclined at an angle to horizontal of no more than about 30 degrees, the angle causing a distal end of the forehearth furthest from the melter exit structure to be raised above a horizontal plane, while a proximal end of the forehearth remains at a level equal to that of the melter exit. 
     
     
         20 . The system of  claim 17  wherein the forehearth is substantially horizontal, and the bushings are configured where a bushing most proximal to the melter exit structure draws molten material at a lowest level in the forehearth and succeeding bushings draw molten material comprising bubbles at progressively higher levels in the forehearth. 
     
     
         21 . The system of  claim 18  wherein the burner comprises one or more flow controllers on the primary conduit, one or more of the alternate gas tubes, and/or one or more of the secondary fuel tubes allowing adjustment of composition of the turbulent molten material and the bubbles suspended in the molten material. 
     
     
         22 . The system of  claim 17  wherein the melter vessel comprises:
 a wall separating the melter vessel into first and second turbulent melting zones; 
 the first turbulent melting zone comprising a first feed opening, a first plurality of burners positioned to direct combustion products into the first turbulent melting zone under a level of first turbulent molten material in the first turbulent melting zone, a first melter exit structure, and a first melting zone dam; 
 the second melting zone further comprising a second feed opening, a second plurality of burners positioned to direct combustion products into the second turbulent melting zone under a level of second turbulent molten material in the second turbulent melting zone, a second melter exit structure, and a second melting zone dam; and 
 wherein the first and second melter exits structures are fluidly connected to the forehearth. 
 
     
     
         23 . The system of  claim 17  comprising:
 a first melter vessel comprising a first feed opening, a first plurality of burners positioned to direct combustion products into a first turbulent melting zone under a level of first turbulent molten material in the first turbulent melting zone, a first melter exit structure for discharging first molten material into a first forehearth, and a first dam; 
 a second melter vessel comprising a second feed opening, a second plurality of burners positioned to direct combustion products into a second turbulent melting zone under a level of second turbulent molten material in the second turbulent melting zone, a second melter exit structure for discharging second molten material into a second forehearth, and a second dam; and 
 the first forehearth fluidly connected to the second forehearth by a distribution channel. 
 
     
     
         24 . The system for making insulating fibers of  claim 17  further comprising:
 c) equipment for producing one or more insulating products selected from fiberglass batting, loose insulating fibers, glass fiber mat, insulation having high organic binder content.