EP-4739633-A1 - METHOD AND SYSTEM FOR HEAT RECOVERY IN AN OXY-FUEL FIRED GLASS FURNACE

EP4739633A1EP 4739633 A1EP4739633 A1EP 4739633A1EP-4739633-A1

Abstract

Processes and systems for glass making can utilize heat recovery to improve operational efficiency and flexibility of operation to provide improved yield, higher quality, or more consistent quality glass, and/or other efficiencies. Some embodiments can utilize adjustments in burner operation to account for different manufacturing conditions to provide improved quality of fabricated glass to provide improved yields of glass with a more efficient utilization of heat, which can improve the environmental impact associated with the manufacturing process in addition to improving the operational efficiency and flexibility of the glass manufacturing process.

Inventors

D'AGOSTINI, MARK DANIEL
DUFFY, Kevin Michael
GALLAGHER, MICHAEL J.
VINOD, ASHWIN

Assignees

Air Products and Chemicals, Inc.

Dates

Publication Date: 20260513
Application Date: 20240626

Claims (20)

1. A method for producing glass comprising: feeding fuel and oxidant to burners of a furnace to combust the fuel to heat glass making material for making glass such that: (i) at least one burner in at least one upstream zone of the furnace operates in a mode of operation in which an inner flow of fuel and an inner flow of oxidant are output into the furnace between an upper oxidant conduit and a lower oxidant conduit such that a flame is formed to project into a combustion chamber of the furnace without upper oxidant staging via the upper oxidant conduit and without lower oxidant staging via the lower oxidant conduit while the oxidant is below a pre-selected hot oxidant temperature threshold; (ii) at least one burner in at least one downstream zone of the furnace that is downstream of the at least one upstream zone of the furnace is operated in a foam control mode of operation in which an upper oxidant flow is passed out of an upper oxidant conduit of the burner along with an inner flow of fuel and an inner flow of oxidant that are output into the furnace so that combustion of the fuel from the at least one burner in the at least one downstream zone of the furnace forms a flame that extends upwardly to provide a reducing atmosphere adjacent the glass making material in the at least one downstream zone of furnace to dissolve foam back into the glass making material while the oxidant is below the pre-selected hot oxidant temperature threshold.
2. The method of claim 1 , comprising: passing flue gas output from the furnace through an oxidant preheater positioned downstream of the furnace between a stack and the furnace for preheating at least a portion of the oxidant before the oxidant is fed to the burners of the furnace.
3. The method of claim 2, comprising: in response to detecting the oxidant is at or above the pre-selected hot oxidant temperature threshold, adjusting operation of the at least one burner in the at least one upstream zone of the furnace so that the at least one burner of the at least one upstream zone of the furnace is adjusted to a split staging mode of operation in which oxidant is passed out of the lower oxidant conduit and is also passed out of the upper oxidant conduit in addition to the oxidant being passed out of the inner oxidant conduit and fuel being passed out of the inner fuel conduit.
4. The method of claim 2, comprising: in response to detecting the oxidant is at a pre-selected hot oxidant temperature threshold, adjusting operation of the at least one burner in the at least one upstream zone of the furnace so that the at least one burner of the at least one upstream zone of the furnace is adjusted to a mode of operation in which the flame has a radiative underside that is promoted via an oxidant flow passed out of the lower oxidant conduit without oxidant staging being provided via the upper oxidant conduit of the at least one burner of the at least one upstream zone.
5. The method of claim 4, wherein the flame has a radiative underside such that radiative heat is directed along an unobstructed radiative path directly to an upper surface of the glass making material in the at least one upstream zone of the furnace.
6. The method of claim 1 , comprising: in response to detecting the oxidant is at or above the pre-selected hot oxidant temperature threshold, adjusting operation of the at least one burner in the at least one upstream zone of the furnace so that the at least one burner of the at least one upstream zone of the furnace is adjusted to a split staging mode of operation in which oxidant is passed out of the lower oxidant conduit and is also passed out of the upper oxidant conduit in addition to the oxidant being passed out of the inner oxidant conduit and fuel being passed out of the inner fuel conduit, or in response to detecting the furnace is at a pre-selected hot furnace temperature, adjusting operation of the at least one burner in the at least one upstream zone of the furnace so that the at least one burner of the at least one upstream zone of the furnace is adjusted to a mode of operation in which the flame has a radiative underside that is promoted via an oxidant flow passed out of the lower oxidant conduit without oxidant staging being provided via the upper oxidant conduit of the at least one burner of the at least one upstream zone; and preheating at least a portion of the oxidant via an oxidant preheater positioned to heat the oxidant before the oxidant is fed to the burners of the furnace via flue gas output from the furnace that is passed through the oxidant preheater; preheating at least a portion of the fuel via a fuel preheater positioned to heat the fuel before the fuel is fed to the burners of the furnace via flue gas output from the furnace that is passed through the fuel preheater.
7. The method of claim 6, comprising: passing the flue gas output from the furnace to a fluid heater to heat a heating medium that is feedable to a glass making feed material pre-heating device; feeding a portion of the glass making material to the glass making feed material preheating device for preheating the portion of the glass making material; outputting the preheated portion of the glass making material from the glass making feed material pre-heating device to feed to the furnace.
8. The method of claim 7, wherein the glass making feed material pre-heating device includes a rotatable shaft having flights that are rotatable to pass the portion of the glass making material fed to the glass making feed material pre-heating device through the glass making feed material pre-heating device.
9. The method of claim 7, comprising: passing heated air through a hollow shaft of the glass making feed material pre-heating device for passing into the portion of the glass making material as it passes through the glass making feed material pre-heating device.
10. The method of claim 9, comprising: forming a slip stream of the heating medium output from the fluid heater to pass through a heat exchanger for heating the air to output the heated air for feeding to the hollow shaft of the glass making feed material pre-heating device.
11. The method of claim 1 , comprising: in response to detecting the oxidant is at or above the pre-selected hot oxidant temperature threshold, adjusting operation of the at least one burner in the at least one downstream zone of the furnace so that the at least one burner of the at least one downstream zone of the furnace is adjusted to a split staging mode of operation in which oxidant is passed out of the lower oxidant conduit and is also passed out of the upper oxidant conduit in addition to the oxidant being passed out of the inner oxidant conduit and fuel being passed out of the inner fuel conduit.
12. The method of claim 1 , comprising: after the oxidant is at or above the pre-selected hot oxidant temperature threshold, adjusting a flow of the oxidant so at least some of the oxidant bypasses an oxidant preheater positioned between the furnace and a stack; and/or after the oxidant is at or above the pre-selected hot oxidant temperature threshold, adjusting a flow of the fuel so at least some of the fuel bypasses a fuel preheater positioned between the furnace and the stack; and/or after the oxidant is at or above the pre-selected hot oxidant temperature threshold, adjusting a flow of the flue gas so that at least a portion of the flue gas bypasses the oxidant preheater and/or the fuel preheater.
13. A system for making glass comprising: a furnace having a plurality of zones that includes a first zone, a second zone, a third zone, a fourth zone, and a fifth zone, the first zone being upstream of the fifth zone, the second zone being between the first zone and the third zone, the third zone being between the second zone and the fourth zone, the fourth zone being between the third zone and the fifth zone; an oxidant preheater positioned between a stack and the furnace, the oxidant preheater positioned to facilitate preheating of oxidant before the oxidant is fed to burners of the furnace via flue gas output from the furnace; a fuel preheater positioned between the stack and the furnace, the fuel preheater positioned to facilitate preheating of fuel before the fuel is fed to burners of the furnace via flue gas output from the furnace; the first zone having at least one burner and the fifth zone having at least one burner; the at least one burner of the first zone configured to: operate in a mode of operation in which an inner flow of fuel and an inner flow of oxidant are output into the first zone of the furnace between an upper oxidant conduit and a lower oxidant conduit such that a flame is formed to project into a combustion chamber of the furnace without upper oxidant staging via the upper oxidant conduit and without lower oxidant staging via the lower oxidant conduit while the oxidant is below a pre-selected hot oxidant temperature threshold, and the at least one burner of the fifth zone configured to: operate in a foam control mode of operation in which an upper oxidant flow is passed out of an upper oxidant conduit of the burner along with an inner flow of fuel and an inner flow of oxidant that are output into the fifth zone of the furnace so that combustion of the fuel from the at least one burner in the fifth zone of the furnace forms a flame that extends upwardly to provide a reducing atmosphere adjacent glass making material in the fifth zone of the furnace to dissolve foam back into the glass making material while the oxidant is below a pre-selected hot oxidant temperature threshold.
14. The system of claim 13, wherein: the at least one burner of the first zone is also configured to adjust operation in response to the furnace being at or above the pre-selected hot oxidant temperature threshold such that the at least one burner in the first zone of the furnace is adjusted to a split staging mode of operation in which oxidant is passed out of the lower oxidant conduit and is also passed out of the upper oxidant conduit in addition to the oxidant being passed out of the inner oxidant conduit and fuel being passed out of the inner fuel conduit; or the at least one burner of the first zone is also configured to adjust operation in response to the oxidant being at or above the pre-selected hot oxidant temperature threshold such that the at least one burner in the first zone of the furnace is adjusted to a mode of operation in which the flame has a radiative underside that is promoted via an oxidant flow passed out of the lower oxidant conduit without oxidant staging being provided via the upper oxidant conduit of the at least one burner of the first zone.
15. The system of claim 13, comprising: a fluid heater positioned to receive flue gas output from the furnace to heat a heating medium that is feedable to a glass making feed material pre-heating device; the glass making feed material pre-heating device positioned to receive a portion of the glass making material to preheat the portion of the glass making material and output the preheated portion of the glass making material for feeding to the first zone of the furnace.
16. The system of claim 15, wherein the glass making feed material pre-heating device includes a rotatable shaft having flights that are rotatable to pass the portion of the glass making material fed to the glass making feed material pre-heating device through the glass making feed material pre-heating device.
17. The system of claim 16, comprising: a heat exchanger positioned to receive a slip stream of the heating medium outputtable from the fluid heater to heat air for feeding the heated air to a hollow shaft of the glass making feed material pre-heating device, the hollow shaft having holes so that the heated air is passable into the portion of the glass making material as it passes through the glass making feed material pre-heating device.
18. The system of claim 13, wherein: the at least one burner of the fifth zone is also configured to adjust operation in response to the furnace being at or above the pre-selected hot oxidant temperature threshold such that the at least one burner in the fifth zone of the furnace is adjusted to a split staging mode of operation in which oxidant is passed out of the lower oxidant conduit and is also passed out of the upper oxidant conduit in addition to the oxidant being passed out of the inner oxidant conduit and fuel being passed out of the inner fuel conduit.
19. An apparatus for preheating glass making material to be fed to a furnace for being heated therein to make glass, the apparatus comprising: a glass making feed material pre-heating device positioned to receive a portion of the glass making material to preheat the portion of the glass making material and output the preheated portion of the glass making material for feeding to the furnace, the glass making feed material pre-heating device comprising: a rotatable shaft having flights positioned in an inner conduit of the glass making feed material pre-heating device, the rotatable shaft being connectable to a motor to drive rotation of the rotatable shaft for moving the portion of the glass making material through the glass making feed material preheating device; the glass making feed material preheating device having an annular conduit that surrounds at least a portion of the inner conduit so that a heating medium is passable through the annular conduit to heat the portion of the glass making material passed through the inner conduit via rotation of the rotatable shaft.
20. The apparatus of claim 19, comprising: a heat exchanger positioned to heat air to output heated air for feeding to the rotatable shaft; and wherein the rotatable shaft is a hollow shaft that has holes, the hollow shaft being configured to receive heated air from the heat exchanger for passing the heated air into the inner conduit via the holes of the hollow shaft.

Description

METHOD AND SYSTEM FOR HEAT RECOVERY IN AN OXY-FUEL FIRED GLASS FURNACE CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims priority to U.S. Provisional Patent Application No. 63/524,752, which was filed on July 3, 2023. TECHNICAL FIELD [0002] This disclosure relates generally to processes and systems for producing glass. More specifically, this disclosure is related to processes and related systems for producing glass with the use of heat recovery. BACKGROUND OF THE INVENTION [0003] Glassmaking is an energy intensive process. The process requires the use of a glass furnace to heat a glassmaking material (e.g., sand, soda ash, limestone, dolomite, feldspar, rouge, cullet, or combinations thereof) at a high enough temperature to melt the glassmaking material thereby forming the glass. In order to achieve these temperatures, the combustion of a hydrocarbon fuel (e.g., natural gas) in the glass furnace is often used necessary. The combustion process, however, produces a gaseous combustion product (known as flue gas) that exits the furnace at temperatures well over 1000°C. The temperature at which the flue gas exits the furnace is a considerable waste of energy unless the flue gas’ heat energy is partially recovered from the flue gas. SUMMARY OF THE INVENTION [0004] We have determined that glass making can be configured to provide a more efficient and flexible utilization of heat to provide enhanced operational efficiency as well as a reduced environmental impact associated with making glass. For example, flue gas from combustion of fuel via one or more burners of a furnace used to melt and form glass from glass raw materials can be operated more flexibly to facilitate improved startup operation as well as improved flame and heat generation that can result in lower nitrous oxide formation and/or improved use of heat from the heat generated via combustion of a fuel. Embodiments can also be configured for providing enhanced flexibility for use of pre-heated oxidant, fuel, and raw material fees to provide a more efficient use of heat as well as providing enhanced flexibility in operation to permit operations to be adapted to different conditions so a more consistent and higher quality glass can be made. [0005] Some embodiments can be configured and implemented so that glassmaking can be provided such that heat energy of the flue gas exiting an oxy-fuel furnace during glassmaking is not only captured, but the overall energy consumption and, optionally, the amount of nitrous oxide (NOx) produced during glassmaking can be lowered while simultaneously improving the overall quality of the glass produced that is produced. Embodiments can also be provided so that the utilization of the flue gas heat that is captured can be adjustable to account for glass making parameters that can affect quality of the glass being made as well as other processing parameters (e.g. temperature of the furnace, etc.). [0006] In a first aspect, a method for producing glass can be provided. The method can include feeding fuel and oxidant to burners of a furnace to combust the fuel to heat glass making material for making glass such that: (i) at least one burner in at least one upstream zone of the furnace operates in a mode of operation in which an inner flow of fuel and an inner flow of oxidant are output into the furnace between an upper oxidant conduit and a lower oxidant conduit such that a flame is formed to project into a combustion chamber of the furnace without upper oxidant staging via the upper oxidant conduit and without lower oxidant staging via the lower oxidant conduit while the oxidant is below a pre-selected hot oxidant temperature threshold, and (ii) at least one burner in at least one downstream zone of the furnace that is downstream of the at least one upstream zone of the furnace is operated in a foam control mode of operation in which an upper oxidant flow is passed out of an upper oxidant conduit of the burner along with an inner flow of fuel and an inner flow of oxidant that are output into the furnace so that combustion of the fuel from the at least one burner in the at least one downstream zone of the furnace forms a flame that extends upwardly to provide a reducing atmosphere adjacent the glass making material in the at least one downstream zone of furnace to dissolve foam back into the glass making material while the oxidant is below the pre-selected hot oxidant temperature threshold. [0007] In some embodiments, all the burners in the at least one upstream zone can operate without upper oxidant staging and lower oxidant staging while the oxidant is below a preselected hot oxidant temperature threshold. Also, all the burners in the at least one downstream zone can operate in the foam control mode. In some embodiments, the upstream zone can be a first zone and the downstream zone can be a second zone. In other embodiments, the at least one upstream zone can include a first zone, a second zone