Zero-carbon glass kiln process

Abstract

Disclosed in the present invention is a zero-carbon glass kiln process. A system required by the process comprises a photovoltaic power generation device, an air separation device, a device for hydrogen production via water electrolysis, a mixer, a methanation device, a waste heat boiler I, a reforming device, a glass kiln, a waste heat boiler II, and a dust removal and desulfurization device. In the present invention, the generation of green oxygen, green nitrogen and green hydrogen is driven by green electricity; flue gas from the glass kiln is cyclically enriched into high-concentration carbon dioxide (95.0 v% or higher), which undergoes a methanation reaction with green hydrogen to generate methane, and methane, carbon dioxide and water vapor are subjected to a reforming reaction to generate carbon monoxide and hydrogen; and carbon monoxide and hydrogen are used as the fuel of the glass kiln, green oxygen and carbon dioxide are mixed to form a carbon-based oxygen-enriched mixture which is used as a combustion improver for the glass kiln to perform carbon-based oxygen-enriched combustion in the glass kiln, and redundant carbon dioxide is sold. The present invention achieves the purposes of greenness, energy conservation, almost zero nitrogen oxides and zero carbon.

Description

A zero-carbon glass kiln process Technical Field

[0001] This invention relates to the field of glass furnace technology, and specifically to a zero-carbon glass furnace process. Background Technology

[0002] Greenhouse gas emissions are the primary cause of global warming, with carbon dioxide accounting for over 70% of the greenhouse effect. Therefore, reducing carbon dioxide emissions is an urgent issue that is crucial for controlling the greenhouse effect and mitigating global warming.

[0003] Currently, the flue gas from domestic glass kilns is basically emitted directly into the atmosphere. Although the carbon emission share of the glass industry is not large, it is a high-energy-consuming and high-emission industry, and the CO2 emission situation is not optimistic. Summary of the Invention

[0004] The purpose of this invention is to provide a zero-carbon glass furnace process to overcome the shortcomings of existing technologies.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A zero-carbon glass furnace process, the system required for the process includes a photovoltaic power generation device, an air separation device, a water electrolysis hydrogen production device, a mixer, a methanation device, a waste heat boiler I, a reforming device, a glass furnace, a waste heat boiler II, and a dust removal and desulfurization device;

[0007] Photovoltaic power generation devices are used to produce green electricity to power air separation units and water electrolysis hydrogen production units.

[0008] Air separation unit, used to produce oxygen and nitrogen;

[0009] A water electrolysis hydrogen production unit, used to produce hydrogen and oxygen;

[0010] A mixer is used to mix oxygen from the air separation unit, oxygen from the water electrolysis hydrogen production unit, and circulating flue gas from the glass furnace into a carbon-based oxygen-enriched mixture.

[0011] The methanation unit is used to react hydrogen from the water electrolysis hydrogen production unit and circulating flue gas from the dust removal and desulfurization unit with methanation.

[0012] Waste heat boiler I is used to recover the waste heat of methane (containing saturated water vapor) from the methanation unit and produce steam as a byproduct.

[0013] The reforming unit is used to reform methane (containing saturated steam) from waste heat boiler I and part of the circulating flue gas from the glass furnace.

[0014] Glass furnaces use carbon monoxide and hydrogen from the reforming unit as fuel and carbon-based oxygen-enriched gas from the mixer as a combustion aid to produce molten glass.

[0015] Waste heat boiler II is used to recover the waste heat from the circulating flue gas sent from the glass kiln and produce steam as a by-product.

[0016] The dust removal and desulfurization unit is used to remove dust and desulfurize the circulating flue gas sent from waste heat boiler II;

[0017] The photovoltaic power generation unit is connected to the air separation unit and the water electrolysis hydrogen production unit, respectively. The nitrogen outlet of the air separation unit is connected to the tin bath and nitrogen product storage tank of the glass furnace, respectively. A pressure reducing valve is installed on the connecting pipe between the nitrogen outlet of the air separation unit and the tin bath of the glass furnace. The oxygen outlets of the air separation unit and the water electrolysis hydrogen production unit are both connected to a mixer. A pressure reducing valve is installed on the connecting pipe between the oxygen outlet of the water electrolysis hydrogen production unit and the mixer. Flow meters and temperature sensors are installed on the connecting pipes between the oxygen outlets of the air separation unit and the water electrolysis hydrogen production unit and the mixer. Detectors, pressure detectors, oxygen purity detectors, flow control valves; the hydrogen outlet of the water electrolysis hydrogen production unit is connected to the methanation unit; the carbon-based oxygen-enriched outlet of the mixer is connected to the A / B heat storage compartment of the glass furnace via a switching connection, and then connected to the glass furnace; the methane outlet of the methanation unit is connected to waste heat boiler I; the methane outlet of waste heat boiler I is connected to the A / B heat storage compartment of the reforming unit via a switching connection, and then connected to the reforming unit; a pressure reducing valve is installed on the connecting pipe between the methane outlet of waste heat boiler I and the A / B heat storage compartment of the reforming unit; the steam outlet of waste heat boiler I is connected to the steam utilization unit. Connections: The carbon monoxide + hydrogen outlet of the reforming unit is connected to the glass furnace; the circulating flue gas outlet of the glass furnace is connected to the heat storage cells B / A of the glass furnace via a switching connection, then to waste heat boiler II and the mixer, and to the heat storage cells A / B of the reforming unit via a switching connection, then to the reforming unit, and to the dust removal and desulfurization unit via a switching connection, with a booster compressor installed on the connecting pipes between the heat storage cells B / A of the glass furnace and waste heat boiler II and the mixer, and a flow meter and temperature sensor installed on the connecting pipes between the heat storage cells B / A of the glass furnace and the mixer. The system includes a temperature detector, a pressure detector, a carbon dioxide purity detector, a flow regulating valve, and a booster compressor connected to the heat storage cells A / B of the glass furnace and the reforming unit, as well as to the heat storage cells B / A of the reforming unit. A pressure reducing valve is installed on the connecting pipe between the heat storage cells B / A of the reforming unit and the dust removal and desulfurization unit. The circulating flue gas outlet of waste heat boiler II is connected to the dust removal and desulfurization unit. The circulating flue gas outlet of the dust removal and desulfurization unit is connected to the methanation unit and the CO2 product storage tank, respectively. A booster compressor is installed on the connecting pipe between the circulating flue gas outlet of the dust removal and desulfurization unit and the methanation unit.

[0018] The process includes the following steps:

[0019] (1) The photovoltaic power generation device produces green electricity to provide power to the air separation unit and the water electrolysis hydrogen production unit; the air separation unit uses the green electricity provided by the photovoltaic power generation device as power to produce oxygen and nitrogen. The oxygen is sent to the mixer, and the nitrogen is partially depressurized and sent to the tin bath of the glass furnace as protective gas. The rest is sold externally; the water electrolysis hydrogen production unit uses the green electricity provided by the photovoltaic power generation device as power to produce hydrogen and oxygen. The hydrogen is sent to the methanation unit, and the oxygen is depressurized and sent to the mixer.

[0020] (2) The mixer mixes the oxygen from the air separation unit and the water electrolysis unit with the circulating flue gas from the glass furnace into carbon-based oxygen-enriched gas, which is used as a combustion aid for the glass furnace.

[0021] (3) The methanation unit reacts the hydrogen from the water electrolysis hydrogen production unit and the circulating flue gas from the dust removal and desulfurization unit with the methanation reaction, and the generated methane (containing saturated water vapor) is sent to waste heat boiler I.

[0022] (4) Waste heat boiler I recovers the waste heat of methane (containing saturated steam) from the methanation unit and produces steam as a by-product; the steam is sold externally, and the methane (containing saturated steam) after waste heat recovery is depressurized and sent to the reforming unit.

[0023] (5) The reforming unit reacts the methane (containing saturated steam) from the waste heat boiler I with a portion of the circulating flue gas from the glass furnace with a methane reforming reaction. The circulating flue gas from the glass furnace enters the reforming unit in two paths. One path enters a heat storage cell on one side of the reforming unit to provide heat to the heat storage cell. In the next round, the heat storage cell will provide heat to the raw gas of the reforming unit. After heat exchange, the circulating flue gas is depressurized and sent to the dust removal and desulfurization unit. The other path and the methane (containing saturated steam) from the waste heat boiler I are sent to the heat storage cell on the other side of the reforming unit. The heat storage cell has been heated by the circulating flue gas in the previous round. The two heat storage cells work in rotation and are heated by the heat of the heat storage cell. Under certain pressure and certain catalyst, methane, carbon dioxide and steam undergo a methane reforming reaction in the reaction bed of the reforming unit to generate carbon monoxide and hydrogen, which are sent to the glass furnace as fuel.

[0024] (6) The glass furnace uses carbon monoxide and hydrogen from the reforming unit as fuel and carbon-based oxygen-enriched gas from the mixer as combustion aid to produce glass melt. The carbon-based oxygen-enriched gas from the mixer first passes through a heat storage cell on one side of the glass furnace. This heat storage cell has been heated by the previous round of circulating flue gas. The two heat storage cells work alternately and are heated to a certain temperature before being sent into the glass furnace.

[0025] After a certain period of circulation and enrichment, the carbon dioxide concentration of the flue gas from the glass furnace reaches equilibrium. The circulating flue gas is divided into two paths. One path passes through the heat storage cell on the other side of the glass furnace, providing heat to the heat storage cell. In the next cycle, the heat storage cell provides heat to the carbon-based oxygen-enriched gas sent by the mixer. After heat exchange, the circulating flue gas in this path is pressurized and sent to the mixer and waste heat boiler II. The other path does not pass through the heat storage cell of the glass furnace and is pressurized before being sent to the reforming unit.

[0026] (7) Waste heat boiler II recovers the waste heat from the circulating flue gas sent from the glass kiln and produces steam as a by-product; the steam is sold externally, and the circulating flue gas after waste heat recovery is sent to the dust removal and desulfurization device.

[0027] (8) The dust removal and desulfurization unit removes dust and desulfurizes the circulating flue gas sent from the waste heat boiler II; after dust removal and desulfurization, part of the circulating flue gas is pressurized and sent to the methanation unit, and the rest is cooled and sold as carbon dioxide products.

[0028] In the initial stage, the glass furnace uses natural gas as fuel and air as a combustion aid. After flue gas is generated, carbon-based oxygen-enriched gas, which is mixed with oxygen produced by the air separation unit and the water electrolysis hydrogen production unit, gradually replaces air for combustion. After a certain period of circulation and enrichment, the carbon dioxide concentration in the circulating flue gas reaches equilibrium, and the methanation unit, reforming unit, waste heat boiler I, waste heat boiler II, and dust removal and desulfurization unit are all put into use, and the system enters normal operation.

[0029] Further, in step (1), the oxygen produced by the air separation unit has a purity of 99.6% or higher, is at room temperature, and has a pressure of 0.2 to 0.3 MPa. The oxygen is sent to the mixer. The nitrogen produced has a purity of 99.9% or higher, is at room temperature, and has a pressure of 0.2 to 0.3 MPa. Part of the nitrogen is depressurized to 0.05 MPa and sent to the tin bath of the glass furnace as a protective gas. The rest is sold externally.

[0030] The hydrogen produced by the water electrolysis hydrogen production unit has a purity of over 99.8% (v%), a temperature of 90–100℃, and a pressure of 2.5–3.0 MPa. The hydrogen is sent to the methanation unit. The oxygen produced has a purity of over 99.0% (v%), a temperature of 90–100℃, and a pressure of 2.5–3.0 MPa. The oxygen is depressurized to 0.2–0.3 MPa and then sent to the mixer.

[0031] Further, in step (2), the oxygen supplied by the air separation unit has a purity of 99.6% or higher, is at room temperature, and has a pressure of 0.2-0.3 MPa; the oxygen supplied by the water electrolysis unit has a purity of 99.0% or higher, a temperature of 90-100℃, and a pressure of 0.2-0.3 MPa; and the carbon dioxide concentration of the circulating flue gas supplied by the glass furnace has a concentration of 95.0% or higher, a temperature of 550-650℃, and a pressure of 0.15-0.25 MPa. The oxygen supplied by the air separation unit, the oxygen supplied by the water electrolysis hydrogen production unit, and the circulating flue gas supplied by the glass furnace are adjusted by regulating valves to form a carbon-based oxygen-enriched mixture with a content of 21-30% vol%, a temperature of 460-480℃, and a pressure of 0.05-0.10 MPa. The oxygen concentration is adjusted according to the requirements of different glass furnaces.

[0032] Further, in step (3), the hydrogen gas supplied by the water electrolysis hydrogen production device has a purity of 99.8% or higher, a temperature of 90-100℃, and a pressure of 2.5-3.0MPa. The circulating flue gas supplied by the dust removal and desulfurization device has a carbon dioxide concentration of 95.0% or higher, a temperature of 250-300℃, and a pressure of 2.5-3.0MPa. The two are fed into the methanation device at a volume ratio of H2:CO2 = 4:1. Under the action of the nickel-based methanation catalyst, hydrogen and carbon dioxide are catalytically converted into methane, while releasing a large amount of heat. The generated methane has a purity of 94.0% or higher (calculated as dry gas), a temperature of 390-410℃, and a pressure of 2.5-3.0MPa. The methane (containing saturated water vapor) is sent to waste heat boiler I.

[0033] Further, in step (4), the temperature of the methane (containing saturated water vapor) sent from the methanation unit is 390-410°C. After the waste heat is recovered by the waste heat boiler I, the temperature is reduced to 240-260°C, and 1.5MPa steam is produced as a by-product for external sale. The methane (containing saturated water vapor) after waste heat recovery is depressurized to 0.5-1.0MPa and then sent to the reforming unit.

[0034] Further, in step (5), the methane (containing saturated water vapor) sent from waste heat boiler I has a methane purity of over 94.0 v% (calculated as dry gas), a temperature of 240–260°C, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace has a carbon dioxide concentration of over 95.0 v%, a temperature of 1300–1400°C, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace enters the reforming unit in two paths. One path enters a heat storage cell on one side of the reforming unit to provide heat to that heat storage cell. In the next cycle, that heat storage cell provides heat to the raw material gas of the reforming unit. After heat exchange, the temperature of the circulating flue gas decreases to 250–300°C, and the pressure is reduced to 0.1–0.2 MPa. The gas is then sent to the dust removal and desulfurization unit at a pressure of MPa. Another route, along with methane (containing saturated steam) from waste heat boiler I, is fed into a heat storage cell on the other side of the reforming unit at a CH4:CO2 volume ratio of 2:1. This heat storage cell has already been heated by the previous cycle of circulating flue gas. The two heat storage cells work alternately, and the gas is heated to 900–1000°C by the heat exchanger. In the reaction bed of the reforming unit, under a pressure of 0.5–1.0 MPa and the action of a nickel-based catalyst, methane, carbon dioxide, and steam undergo a methane reforming reaction to produce carbon monoxide and hydrogen, with a CO:H2 volume ratio of approximately 3:5. The outlet temperature is 700–800°C, and the pressure is 0.5–1.0 MPa, which is then used as fuel for the glass furnace.

[0035] Further, in step (6), the carbon monoxide and hydrogen supplied by the reforming unit have a CO:H2 volume ratio of approximately 3:5, a temperature of 700-800℃, and a pressure of 0.5-1.0MPa. The carbon-based oxygen-enriched gas supplied by the mixer has an oxygen content of 21-30v%, a temperature of 460-480℃, and a pressure of 0.05-0.10MPa. The carbon-based oxygen-enriched gas supplied by the mixer first passes through a heat storage cell on one side of the glass furnace, which has been heated by the previous round of circulating flue gas. The heat storage cells on both sides work alternately and are heated to 700-800℃ before being sent into the glass furnace. The fuel:combustion aid volume ratio is approximately 1:2. In the glass furnace, carbon monoxide and hydrogen undergo a combustion reaction under the combustion aid of carbon-based oxygen-enriched gas, providing heat for the glass furnace to produce molten glass.

[0036] After 3-5 hours of circulation and enrichment, the carbon dioxide concentration in the glass furnace reaches equilibrium, exceeding 95.0% v%, with a temperature of 1300-1400℃ and a pressure of 0.01-0.05 MPa. The circulating flue gas is divided into two paths. One path passes through a heat storage cell on the other side of the glass furnace, providing heat to that cell. In the next cycle, this heat storage cell provides heat to the carbon-based oxygen-enriched gas from the mixer. After heat exchange, the circulating flue gas in this path is cooled to 550-650℃ and pressurized to 0.15-0.25 MPa before being sent to the mixer and waste heat boiler II. The other path does not pass through the glass furnace heat storage cell, maintaining a temperature of 1300-1400℃ and a pressure of 0.5-1.0 MPa before being sent to the reforming unit.

[0037] Furthermore, in step (7), the circulating flue gas from the glass kiln has a carbon dioxide concentration of over 95.0% and a temperature of 550–650°C and a pressure of 0.15–0.25 MPa. After being recovered by the waste heat boiler II, the temperature is reduced to 250–300°C and the pressure is 0.1–0.2 MPa, and 1.5–4.0 MPa steam is produced as a byproduct for sale. The circulating flue gas after waste heat recovery is sent to the dust removal and desulfurization device.

[0038] Furthermore, the dust removal and desulfurization device consists of two parts: a high-temperature dust collector and a dry desulfurization device; the high-temperature dust collector uses cyclone separation for dust removal, and the dry desulfurization device uses zinc oxide desulfurization.

[0039] Step (8) The circulating flue gas first passes through the high-temperature dust collector in the dust removal and desulfurization device to remove dust, and then passes through the dry desulfurization equipment in the dust removal and desulfurization device to remove hydrogen sulfide; the circulating flue gas sent from the waste heat boiler II has a carbon dioxide concentration of more than 95.0 v%, a temperature of 250-300℃, and a pressure of 0.1-0.2 MPa. The circulating flue gas after dust removal and desulfurization has a carbon dioxide concentration of more than 95.0 v%, a temperature of 250-300℃, and a pressure of 0.05-0.10 MPa. Part of it is pressurized to 2.5-3.0 MPa and sent to the methanation device, and the rest is cooled down and sold as carbon dioxide products.

[0040] Furthermore, in the initial stage, the glass furnace uses natural gas as fuel and air as a combustion aid. After flue gas is generated, carbon-based oxygen-enriched gas, which is mixed with oxygen produced by the air separation unit and the water electrolysis hydrogen production unit, gradually replaces the air for combustion. After 3 to 5 hours of circulation and enrichment, the carbon dioxide concentration in the circulating flue gas reaches equilibrium, with a carbon dioxide concentration of over 95.0%v%. The methanation unit, reforming unit, waste heat boiler I, waste heat boiler II, and dust removal and desulfurization unit are all put into use, and the system enters normal operation.

[0041] The beneficial effects of this invention are:

[0042] 1. This invention employs green electricity to drive an air separation unit to produce green oxygen and green nitrogen, and to drive a water electrolysis hydrogen production unit to produce green hydrogen and green oxygen. The flue gas from the glass furnace is recycled and enriched into a high concentration of carbon dioxide (above 95.0 vol%), which reacts with the green hydrogen in a methanation reaction to produce methane. The methane then undergoes a reforming reaction with carbon dioxide and water vapor to produce carbon monoxide and hydrogen. Carbon monoxide and hydrogen serve as fuel for the glass furnace, while green oxygen and carbon dioxide are mixed to form carbon-based oxygen-enriched fuel, which is used as a combustion aid in the glass furnace for carbon-based oxygen-enriched combustion. Excess carbon dioxide is sold off. This invention achieves the goals of being green, energy-saving, virtually free of nitrogen oxides, and zero-carbon.

[0043] 2. This invention uses green electricity generated by a photovoltaic power generation device to drive an air separation unit to produce green oxygen and green nitrogen, and uses green electricity generated by a photovoltaic power generation device to drive a water electrolysis hydrogen production unit to produce green hydrogen and green oxygen, which is green and environmentally friendly.

[0044] 3. The flue gas of the glass furnace of this invention is enriched with carbon dioxide at a concentration of more than 95.0% in the circulating system. This carbon dioxide is used as a raw material for methanation, reforming, and carbon-based oxygen-enriched combustion in the glass furnace. The excess carbon dioxide is sold as a product, thus truly achieving a zero-carbon glass furnace.

[0045] 4. This invention uses green hydrogen produced by a water electrolysis hydrogen production device and high-concentration carbon dioxide (above 95.0 vol%) enriched in flue gas as raw materials for methanation to produce methane, making use of waste carbon dioxide and improving the utilization rate of waste resources.

[0046] 5. This invention uses methane produced by a methanation unit, high-concentration carbon dioxide (over 95.0 vol%) enriched in flue gas, and water vapor as raw materials to produce carbon monoxide and hydrogen through a reforming reaction, thereby increasing the calorific value of the fuel and reducing fuel consumption.

[0047] 6. This invention uses high-concentration carbon dioxide (over 95.0% v%) enriched in flue gas to replace air for carbon-based oxygen-enriched combustion, which can produce almost no nitrogen oxides during the combustion process. At the same time, since carbon dioxide is a greenhouse gas, it improves the thermal efficiency of the glass furnace.

[0048] 7. The present invention enriches the flue gas with high concentrations of carbon dioxide (above 95.0% v%), creating conditions for low-cost carbon dioxide capture and making zero-carbon glass furnaces possible.

[0049] 8. This invention combines methanation and reforming with a glass furnace, making full use of the heat from the flue gas in the glass furnace to exchange heat with the raw material gas, thereby improving the heat utilization rate. Attached Figure Description

[0050] Figure 1 is a schematic diagram of the system structure required for the zero-carbon glass furnace process of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Therefore, the following detailed description of the embodiments of this invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0052] A zero-carbon glass furnace process, the system required for which is shown in Figure 1, includes a photovoltaic power generation device, an air separation device, a water electrolysis hydrogen production device, a mixer, a methanation device, a waste heat boiler I, a reforming device, a glass furnace, a waste heat boiler II, and a dust removal and desulfurization device.

[0053] Photovoltaic power generation devices are used to produce green electricity, providing power to air separation units and water electrolysis hydrogen production units. The main principle of photovoltaic power generation is the photoelectric effect of semiconductors. Under the illumination of electromagnetic waves of a frequency higher than a certain threshold frequency, electrons inside certain materials absorb energy and escape to form an electric current, i.e., photoelectric power generation. Photovoltaic power generation has the advantages of being safe and reliable, noiseless, pollution-free, absolutely clean, and harmless.

[0054] An air separation unit uses green electricity generated by a photovoltaic power plant to produce oxygen and nitrogen. The process involves compressing, cooling, and liquefying air. Utilizing the difference in boiling points between oxygen and nitrogen, the gas and liquid components come into contact on distillation trays, exchanging mass and heat. The higher-boiling-point oxygen component continuously condenses from the vapor into liquid, while the lower-boiling-point nitrogen component continuously transfers into the vapor. This process continuously increases the nitrogen content in the rising vapor and the oxygen content in the flowing liquid, thus separating the oxygen and nitrogen. The air separation unit produces oxygen with a purity of ≥99.6% at room temperature and a pressure of 0.2–0.3 MPa, and nitrogen with a purity of ≥99.9% at room temperature and a pressure of 0.2–0.3 MPa. Because the air separation unit uses green electricity generated by the photovoltaic power plant, the oxygen produced is called "green oxygen," and the nitrogen produced is called "green nitrogen." Oxygen produced by the air separation unit is mixed with oxygen from the mixer and the water electrolysis hydrogen production unit, as well as circulating flue gas (with a carbon dioxide concentration of over 95.0%) from the glass furnace, to form carbon-based oxygen-enriched gas for combustion in the glass furnace. Part of the nitrogen produced by the air separation unit is depressurized to 0.05 MPa and sent to the tin bath of the glass furnace as a protective gas; the remainder is sold externally.

[0055] The water electrolysis hydrogen production unit uses green electricity provided by a photovoltaic power generation device to produce hydrogen and oxygen. Water electrolysis is a relatively convenient method for producing hydrogen. Direct current is passed through an electrolytic cell filled with electrolyte, causing water molecules to undergo an electrochemical reaction at the electrodes, decomposing into nitrogen and oxygen. The hydrogen produced by the water electrolysis hydrogen production unit has a purity of over 99.8% (v%), a temperature of 90–100℃, and a pressure of 2.5–3.0 MPa. The oxygen produced also has a purity of over 99.0% (v%), a temperature of 90–100℃, and a pressure of 2.5–3.0 MPa. Because the water electrolysis hydrogen production unit uses green electricity generated by the photovoltaic power generation device, the hydrogen produced is green hydrogen, and the oxygen produced is green oxygen. The hydrogen produced by the water electrolysis hydrogen production unit is sent to a methanation unit for the methanation reaction. The oxygen produced by the water electrolysis hydrogen production unit is depressurized to 0.2-0.3 MPa and then sent to the mixer and the oxygen from the air separation unit, and the circulating flue gas (carbon dioxide concentration above 95.0%) from the glass furnace to be mixed into carbon-based oxygen-enriched gas as a combustion aid for the glass furnace.

[0056] The equation for hydrogen production via water electrolysis is: 2H₂O → 2H₂ + O₂

[0057] The mixer is used to mix oxygen from the air separation unit, oxygen from the water electrolysis hydrogen production unit, and circulating flue gas from the glass furnace to form a carbon-based oxygen-enriched mixture, which serves as a combustion aid in the glass furnace. The oxygen from the air separation unit has a purity of ≥99.6 vol%, is supplied at room temperature, and has a pressure of 0.2–0.3 MPa. The oxygen from the water electrolysis hydrogen production unit has a purity of ≥99.0 vol%, a temperature of 90–100℃, and a pressure of 0.2–0.3 MPa. The circulating flue gas from the glass furnace has a carbon dioxide concentration of ≥95.0 vol%, a temperature of 550–650℃, and a pressure of 0.15–0.25 MPa. Oxygen from the air separation unit, oxygen from the water electrolysis hydrogen production unit, and circulating flue gas from the glass furnace are mixed after their flow rates are regulated by regulating valves to form a carbon-based oxygen-enriched agent with an oxygen content of 21-30% v%, a temperature of 460-480℃, and a pressure of 0.05-0.10 MPa. This agent is used as a combustion aid in the glass furnace, and the oxygen concentration is adjusted according to the requirements of different glass furnaces.

[0058] The methanation unit is used to react hydrogen from the water electrolysis hydrogen production unit and circulating flue gas from the dust removal and desulfurization unit. The hydrogen from the water electrolysis hydrogen production unit has a purity of ≥99.8 vol%, a temperature of 90–100℃, and a pressure of 2.5–3.0 MPa. The circulating flue gas from the dust removal and desulfurization unit has a carbon dioxide concentration of ≥95.0 vol%, a temperature of 250–300℃, and a pressure of 2.5–3.0 MPa. Both are fed into the methanation unit at a volume ratio of H2:CO2 = 4:1. Under the action of a nickel-based methanation catalyst, hydrogen and carbon dioxide are catalytically converted into methane, releasing a large amount of heat. The generated methane has a purity of ≥94.0 vol% (dry gas), a temperature of 390–410℃, and a pressure of 2.5–3.0 MPa. The methane (containing saturated water vapor) is sent to waste heat boiler I.

[0059] Methanation reaction equation: 4H₂ + CO₂ → CH₄ + 2H₂O

[0060] Waste heat boiler I is used to recover the waste heat from methane (containing saturated steam) from the methanation unit and produce steam as a byproduct. The methane (containing saturated steam) from the methanation unit has a temperature of 390–410°C. After waste heat recovery in waste heat boiler I, the temperature is reduced to 240–260°C, and 1.5 MPa steam is produced as a byproduct for sale. Because the optimal pressure for the reforming reaction is 0.5–1.0 MPa, the methane (containing saturated steam) after waste heat recovery is depressurized to 0.5–1.0 MPa before being sent to the reforming unit.

[0061] The reforming unit is used to reform methane (containing saturated steam) from waste heat boiler I and a portion of the circulating flue gas from the glass furnace. The methane (containing saturated steam) from waste heat boiler I has a purity of ≥94.0 vol% (dry gas calculation), a temperature of 240–260℃, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace has a carbon dioxide concentration of ≥95.0 vol%, a temperature of 1300–1400℃, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace is divided into two paths and enters the reforming unit. One path enters a heat storage cell on one side of the reforming unit, providing heat to that cell. In the next cycle, this heat storage cell then provides heat to the feed gas of the reforming unit. After heat exchange, the temperature of the circulating flue gas is reduced to 250-300℃, and the pressure is reduced to 0.1-0.2MPa before being sent to the dust removal and desulfurization unit. The other path, along with methane (containing saturated steam) from waste heat boiler I, is sent to the heat storage cell on the other side of the reforming unit at a CH4:CO2 volume ratio of 2:1. The heat exchanger (which has been heated by the previous cycle of circulating flue gas, and the two heat exchangers work alternately) is heated to 900-1000℃ by the heat exchanger. In the reaction bed of the reforming unit, under the pressure of 0.5-1.0MPa and the action of a nickel-based catalyst, methane, carbon dioxide and water vapor undergo a methane reforming reaction to produce carbon monoxide and hydrogen. The CO:H2 volume ratio is about 3:5. The outlet temperature is 700-800℃ and the pressure is 0.5-1.0MPa. This gas is then sent as fuel to the glass furnace.

[0062] Reforming reaction equation: CH4 + H2O → CO + 3H2

[0063] CH4 + CO2 → 2CO + 2H2

[0064] The glass furnace uses carbon monoxide and hydrogen from the reforming unit as fuel (natural gas is used initially), and carbon-based oxygen-enriched gas from the mixer as a combustion aid to produce molten glass. The carbon monoxide and hydrogen from the reforming unit have a CO:H2 volume ratio of approximately 3:5, a temperature of 700–800℃, and a pressure of 0.5–1.0 MPa. The carbon-based oxygen-enriched gas from the mixer has an oxygen content of 21–30 v%, a temperature of 460–480℃, and a pressure of 0.05–0.10 MPa. This gas first passes through a regenerator on one side of the glass furnace (this regenerator has already been heated by the previous cycle of circulating flue gas; the two regenerators operate alternately), and is heated to 700–800℃ before being fed into the glass furnace. The fuel (carbon monoxide and hydrogen from the reforming unit) to combustion aid (carbon-based oxygen-enriched gas from the mixer) volume ratio is approximately 1:2. In a glass furnace, carbon monoxide and hydrogen undergo a combustion reaction under the aid of carbon-based oxygen-enriched combustion, providing heat for the production of molten glass in the glass furnace.

[0065] Carbon-based oxygen-enriched combustion reaction equation: 2CO + O2 + CO2 → 3CO2

[0066] 2H₂ + O₂ + CO₂ → 2H₂O + CO₂

[0067] After 3-5 hours of circulation and enrichment, the carbon dioxide concentration in the glass furnace reaches equilibrium, exceeding 95.0% v%, with a temperature of 1300-1400℃ and a pressure of 0.01-0.05 MPa. The circulating flue gas is divided into two paths. One path passes through a heat storage cell on the other side of the glass furnace, providing heat to that cell. In the next cycle, this heat storage cell provides heat to the carbon-based oxygen-enriched gas from the mixer. After heat exchange, this path of circulating flue gas is cooled to 550-650℃ and pressurized to 0.15-0.25 MPa before being sent to the mixer and waste heat boiler II. The other path does not pass through the glass furnace heat storage cell, maintaining a temperature of 1300-1400℃ and a pressure of 0.5-1.0 MPa before being sent to the reforming unit.

[0068] Waste heat boiler II is used to recover waste heat from the circulating flue gas from the glass kiln and produce steam as a byproduct. The circulating flue gas from the glass kiln has a carbon dioxide concentration of over 95.0% (v%), a temperature of 550–650℃, and a pressure of 0.15–0.25 MPa. After waste heat recovery by waste heat boiler II, the temperature is reduced to 250–300℃, and the pressure is 0.1–0.2 MPa, producing 1.5–4.0 MPa steam as a byproduct, which is sold externally. The circulating flue gas after waste heat recovery is sent to a dust removal and desulfurization unit.

[0069] The dust removal and desulfurization unit is used to remove dust and desulfurize the circulating flue gas from Waste Heat Boiler II. The unit consists of two parts: a high-temperature dust collector and a dry desulfurization device. The high-temperature dust collector uses cyclone separation for dust removal, while the dry desulfurization device uses zinc oxide for desulfurization. The circulating flue gas first passes through the high-temperature dust collector to remove dust, and then passes through the dry desulfurization device to remove hydrogen sulfide. The circulating flue gas from Waste Heat Boiler II has a carbon dioxide concentration of over 95.0 vol%, a temperature of 250–300℃, and a pressure of 0.1–0.2 MPa. After dust removal and desulfurization, the circulating flue gas has a carbon dioxide concentration of over 95.0 vol%, a temperature of 250–300℃, and a pressure of 0.05–0.10 MPa. Part of it is pressurized to 2.5–3.0 MPa and sent to the methanation unit, while the remainder is cooled and sold as carbon dioxide.

[0070] Dry desulfurization reaction equation: ZnO + H₂S → ZnS + H₂O

[0071] The photovoltaic power generation unit is connected to the air separation unit and the water electrolysis hydrogen production unit, respectively. The nitrogen outlet of the air separation unit is connected to the tin bath and nitrogen product storage tank of the glass furnace, respectively. A pressure reducing valve is installed on the connecting pipe between the nitrogen outlet of the air separation unit and the tin bath of the glass furnace. The oxygen outlet of the air separation unit and the oxygen outlet of the water electrolysis hydrogen production unit are both connected to a mixer. A pressure reducing valve is installed on the connecting pipe between the oxygen outlet of the water electrolysis hydrogen production unit and the mixer. A flow meter F and a temperature meter T are installed on the connecting pipe between the oxygen outlet of the air separation unit and the oxygen outlet of the water electrolysis hydrogen production unit and the mixer. Pressure gauge P, gas (oxygen) purity gauge C, flow control valve FIC; hydrogen outlet of water electrolysis hydrogen production unit connected to methanation unit; carbon-based oxygen-enriched outlet of mixer connected to heat storage cells A / B of glass furnace via switching connection, then connected to glass furnace; methane outlet of methanation unit connected to waste heat boiler I; methane outlet of waste heat boiler I connected to heat storage cells A / B of reforming unit via switching connection, then connected to reforming unit; pressure reducing valve installed on the connecting pipe between methane outlet of waste heat boiler I and heat storage cells A / B of reforming unit; steam outlet of waste heat boiler I connected to steam utilization unit. Connections: The carbon monoxide + hydrogen outlet of the reforming unit is connected to the glass furnace; the circulating flue gas outlet of the glass furnace is connected to the heat storage cells B / A of the glass furnace via a switching connection, then to waste heat boiler II and the mixer, and to the heat storage cells A / B of the reforming unit via a switching connection, then to the reforming unit, and to the dust removal and desulfurization unit via a switching connection of the heat storage cells B / A of the reforming unit via a switching connection, and finally to the dust removal and desulfurization unit. A booster compressor is installed on the connecting pipes between the heat storage cells B / A of the glass furnace and waste heat boiler II and the mixer. A flow meter F and a temperature meter are installed on the connecting pipes between the heat storage cells B / A of the glass furnace and the mixer. The following equipment is installed: T, pressure detector P, gas (carbon dioxide) purity detector C, flow regulating valve FIC; booster compressors are installed on the connecting pipes of heat storage cells A / B of the glass furnace and reforming unit, and heat storage cells B / A of the reforming unit; pressure reducing valves are installed on the connecting pipes of heat storage cells B / A of the reforming unit and the dust removal and desulfurization unit; the circulating flue gas outlet of waste heat boiler II is connected to the dust removal and desulfurization unit; the circulating flue gas outlet of the dust removal and desulfurization unit is connected to the methanation unit and CO2 product storage tank respectively; booster compressors are installed on the connecting pipes of the circulating flue gas outlet of the dust removal and desulfurization unit and the methanation unit.

[0072] The process includes the following steps:

[0073] (1) The photovoltaic power generation device produces green electricity to provide power to the air separation unit and the water electrolysis hydrogen production unit. The air separation unit uses the green electricity provided by the photovoltaic power generation device to produce oxygen and nitrogen. The oxygen has a purity of 99.6% or higher, is at room temperature, and has a pressure of 0.2 to 0.3 MPa. The oxygen is sent to the mixer. The nitrogen has a purity of 99.9% or higher, is at room temperature, and has a pressure of 0.2 to 0.3 MPa. Some of the nitrogen is depressurized to 0.05 MPa and sent to the tin bath of the glass furnace as a protective gas. The rest is sold externally. The water electrolysis hydrogen production unit uses green electricity provided by the photovoltaic power generation unit to produce hydrogen and oxygen. The hydrogen has a purity of over 99.8% v%, a temperature of 90-100℃, and a pressure of 2.5-3.0 MPa. The hydrogen is sent to the methanation unit. The oxygen has a purity of over 99.0% v%, a temperature of 90-100℃, and a pressure of 2.5-3.0 MPa. The oxygen is depressurized to 0.2-0.3 MPa and then sent to the mixer.

[0074] (2) The mixer mixes the oxygen from the air separation unit and the water electrolysis unit with the circulating flue gas from the glass furnace to form a carbon-based oxygen-enriched mixture, which serves as the combustion aid for the glass furnace. The oxygen from the air separation unit has a purity of ≥99.6 vol%, is at room temperature, and has a pressure of 0.2–0.3 MPa. The oxygen from the water electrolysis unit has a purity of ≥99.0 vol%, a temperature of 90–100 °C, and a pressure of 0.2–0.3 MPa. The circulating flue gas from the glass furnace has a carbon dioxide concentration of ≥95.0 vol%, a temperature of 550–650 °C, and a pressure of 0.15–0.25 MPa. The oxygen from the air separation unit, the oxygen from the water electrolysis hydrogen production unit, and the circulating flue gas from the glass furnace are all regulated by regulating valves. The resulting carbon-based oxygen-enriched mixture has a content of 21-30 vol%, a temperature of 460-480℃, and a pressure of 0.05-0.10 MPa. The oxygen concentration is adjusted according to the requirements of different glass furnaces.

[0075] (3) The methanation unit reacts hydrogen from the water electrolysis hydrogen production unit with circulating flue gas from the dust removal and desulfurization unit. The hydrogen from the water electrolysis hydrogen production unit has a purity of 99.8% or higher, a temperature of 90-100℃, and a pressure of 2.5-3.0 MPa. The circulating flue gas from the dust removal and desulfurization unit has a carbon dioxide concentration of 95.0% or higher, a temperature of 250-300℃, and a pressure of 2.5-3.0 MPa. The two are fed into the methanation unit at a volume ratio of H2:CO2 = 4:1. Under the action of the nickel-based methanation catalyst, hydrogen and carbon dioxide are catalytically converted into methane, releasing a large amount of heat. The generated methane has a purity of 94.0% or higher (dry gas), a temperature of 390-410℃, and a pressure of 2.5-3.0 MPa. The methane (containing saturated water vapor) is sent to waste heat boiler I.

[0076] (4) Waste heat boiler I recovers the waste heat from the methane (containing saturated steam) from the methanation unit and produces steam as a byproduct. The methane (containing saturated steam) from the methanation unit has a temperature of 390-410℃. After waste heat recovery by waste heat boiler I, the temperature is reduced to 240-260℃, and 1.5MPa steam is produced as a byproduct for sale. The methane (containing saturated steam) after waste heat recovery is depressurized to 0.5-1.0MPa and then sent to the reforming unit.

[0077] (5) The reforming unit reacts the methane (containing saturated steam) from waste heat boiler I with a portion of the circulating flue gas from the glass furnace in a methane reforming reaction. The methane (containing saturated steam) from waste heat boiler I has a purity of ≥94.0 v% (dry gas calculation), a temperature of 240–260 °C, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace has a carbon dioxide concentration of ≥95.0 v%, a temperature of 1300–1400 °C, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace is divided into two paths and enters the reforming unit. One path enters a heat storage cell on one side of the reforming unit, providing heat to that cell. In the next cycle, this heat storage cell then provides heat to the feed gas of the reforming unit. After heat exchange, the temperature of the circulating flue gas is reduced to 250-300℃, and the pressure is reduced to 0.1-0.2MPa before being sent to the dust removal and desulfurization unit. The other path, along with methane (containing saturated steam) from waste heat boiler I, is sent to the heat storage cell on the other side of the reforming unit at a CH4:CO2 volume ratio of 2:1. The heat exchanger (which has been heated by the previous cycle of circulating flue gas, and the two heat exchangers work alternately) is heated to 900-1000℃ by the heat exchanger. In the reaction bed of the reforming unit, under the pressure of 0.5-1.0MPa and the action of a nickel-based catalyst, methane, carbon dioxide and water vapor undergo a methane reforming reaction to produce carbon monoxide and hydrogen. The CO:H2 volume ratio is about 3:5. The outlet temperature is 700-800℃ and the pressure is 0.5-1.0MPa. This gas is then sent as fuel to the glass furnace.

[0078] (6) The glass furnace uses carbon monoxide and hydrogen from the reforming unit as fuel (natural gas is used as fuel in the initial stage of production) and carbon-based oxygen-enriched gas from the mixer as a combustion aid to produce molten glass. The carbon monoxide and hydrogen from the reforming unit have a CO:H2 volume ratio of approximately 3:5, a temperature of 700-800℃, and a pressure of 0.5-1.0MPa. The carbon-based oxygen-enriched gas from the mixer has an oxygen content of 21-30v%, a temperature of 460-480℃, and a pressure of 0.05-0.10MPa. The carbon-based oxygen-enriched gas from the mixer first passes through a heat storage cell on one side of the glass furnace (this heat storage cell has been heated by the previous round of circulating flue gas, and the two heat storage cells work alternately), and is heated to 700-800℃ before being sent into the glass furnace. The volume ratio of fuel (carbon monoxide and hydrogen from the reforming unit): combustion aid (carbon-based oxygen-enriched gas from the mixer) is approximately 1:2. In a glass furnace, carbon monoxide and hydrogen undergo a combustion reaction under the aid of carbon-based oxygen-enriched combustion, providing heat for the production of molten glass in the glass furnace.

[0079] After 3-5 hours of circulation and enrichment, the carbon dioxide concentration in the glass furnace reaches equilibrium, exceeding 95.0% v%, with a temperature of 1300-1400℃ and a pressure of 0.01-0.05 MPa. The circulating flue gas is divided into two paths. One path passes through a heat storage cell on the other side of the glass furnace, providing heat to that cell. In the next cycle, this heat storage cell provides heat to the carbon-based oxygen-enriched gas from the mixer. After heat exchange, this path of circulating flue gas is cooled to 550-650℃ and pressurized to 0.15-0.25 MPa before being sent to the mixer and waste heat boiler II. The other path does not pass through the glass furnace heat storage cell, maintaining a temperature of 1300-1400℃ and a pressure of 0.5-1.0 MPa before being sent to the reforming unit.

[0080] (7) Waste heat boiler II recovers the waste heat from the circulating flue gas sent from the glass kiln and produces steam as a byproduct. The circulating flue gas sent from the glass kiln has a carbon dioxide concentration of over 95.0%v%, a temperature of 550-650℃, and a pressure of 0.15-0.25MPa. After waste heat recovery by waste heat boiler II, the temperature is reduced to 250-300℃ and the pressure is 0.1-0.2MPa, and 1.5-4.0MPa steam is produced as a byproduct for sale. The circulating flue gas after waste heat recovery is sent to the dust removal and desulfurization unit.

[0081] (8) The dust removal and desulfurization unit removes dust and desulfurizes the circulating flue gas from waste heat boiler II. The circulating flue gas first passes through the high-temperature dust collector in the dust removal and desulfurization unit to remove dust, and then passes through the dry desulfurization equipment in the dust removal and desulfurization unit to remove hydrogen sulfide. The circulating flue gas from waste heat boiler II has a carbon dioxide concentration of over 95.0 vol%, a temperature of 250-300℃, and a pressure of 0.1-0.2 MPa. The circulating flue gas after dust removal and desulfurization has a carbon dioxide concentration of over 95.0 vol%, a temperature of 250-300℃, and a pressure of 0.05-0.10 MPa. Part of it is pressurized to 2.5-3.0 MPa and sent to the methanation unit, while the rest is cooled and sold as carbon dioxide products.

[0082] In the initial stage, the glass furnace uses natural gas as fuel and air as a combustion aid. After flue gas is generated, carbon-based oxygen-enriched gas, which is a mixture of flue gas and oxygen (produced by air separation unit and water electrolysis hydrogen production unit), is gradually used to replace air for combustion aid. After 3 to 5 hours of circulation and enrichment, the carbon dioxide concentration in the circulating flue gas reaches equilibrium, with a carbon dioxide concentration of over 95.0%v%. The methanation unit, reforming unit, waste heat boiler I, waste heat boiler II, and dust removal and desulfurization unit are all put into use, and the system enters normal operation.

Claims

1. A zero-carbon glass furnace process, characterized in that, The system required for the process includes a photovoltaic power generation unit, an air separation unit, a water electrolysis hydrogen production unit, a mixer, a methanation unit, a waste heat boiler I, a reforming unit, a glass furnace, a waste heat boiler II, and a dust removal and desulfurization unit. Photovoltaic power generation devices are used to produce green electricity to power air separation units and water electrolysis hydrogen production units. Air separation unit, used to produce oxygen and nitrogen; A water electrolysis hydrogen production unit, used to produce hydrogen and oxygen; A mixer is used to mix oxygen from the air separation unit, oxygen from the water electrolysis hydrogen production unit, and circulating flue gas from the glass furnace into a carbon-based oxygen-enriched mixture. The methanation unit is used to react hydrogen from the water electrolysis hydrogen production unit and circulating flue gas from the dust removal and desulfurization unit with methanation. Waste heat boiler I is used to recover the waste heat of methane (containing saturated water vapor) from the methanation unit and produce steam as a byproduct. The reforming unit is used to reform methane (containing saturated steam) from waste heat boiler I and part of the circulating flue gas from the glass furnace. Glass furnaces use carbon monoxide and hydrogen from the reforming unit as fuel and carbon-based oxygen-enriched gas from the mixer as a combustion aid to produce molten glass. Waste heat boiler II is used to recover the waste heat from the circulating flue gas sent from the glass kiln and produce steam as a by-product. The dust removal and desulfurization unit is used to remove dust and desulfurize the circulating flue gas sent from waste heat boiler II; The photovoltaic power generation unit is connected to the air separation unit and the water electrolysis hydrogen production unit, respectively. The nitrogen outlet of the air separation unit is connected to the tin bath and nitrogen product storage tank of the glass furnace, respectively. A pressure reducing valve is installed on the connecting pipe between the nitrogen outlet of the air separation unit and the tin bath of the glass furnace. The oxygen outlets of the air separation unit and the water electrolysis hydrogen production unit are both connected to a mixer. A pressure reducing valve is installed on the connecting pipe between the oxygen outlet of the water electrolysis hydrogen production unit and the mixer. Flow meters and temperature sensors are installed on the connecting pipes between the oxygen outlets of the air separation unit and the water electrolysis hydrogen production unit and the mixer. Detectors, pressure detectors, oxygen purity detectors, flow control valves; the hydrogen outlet of the water electrolysis hydrogen production unit is connected to the methanation unit; the carbon-based oxygen-enriched outlet of the mixer is connected to the A / B heat storage compartment of the glass furnace via a switching connection, and then connected to the glass furnace; the methane outlet of the methanation unit is connected to waste heat boiler I; the methane outlet of waste heat boiler I is connected to the A / B heat storage compartment of the reforming unit via a switching connection, and then connected to the reforming unit; a pressure reducing valve is installed on the connecting pipe between the methane outlet of waste heat boiler I and the A / B heat storage compartment of the reforming unit; the steam outlet of waste heat boiler I is connected to the steam utilization unit. Connections: The carbon monoxide + hydrogen outlet of the reforming unit is connected to the glass furnace; the circulating flue gas outlet of the glass furnace is connected to the heat storage cells B / A of the glass furnace via a switching connection, then to waste heat boiler II and the mixer, and to the heat storage cells A / B of the reforming unit via a switching connection, then to the reforming unit, and to the dust removal and desulfurization unit via a switching connection, with a booster compressor installed on the connecting pipes between the heat storage cells B / A of the glass furnace and waste heat boiler II and the mixer, and a flow meter and temperature sensor installed on the connecting pipes between the heat storage cells B / A of the glass furnace and the mixer. The system includes a temperature detector, a pressure detector, a carbon dioxide purity detector, a flow regulating valve, and a booster compressor connected to the heat storage cells A / B of the glass furnace and the reforming unit, as well as to the heat storage cells B / A of the reforming unit. A pressure reducing valve is installed on the connecting pipe between the heat storage cells B / A of the reforming unit and the dust removal and desulfurization unit. The circulating flue gas outlet of waste heat boiler II is connected to the dust removal and desulfurization unit. The circulating flue gas outlet of the dust removal and desulfurization unit is connected to the methanation unit and the CO2 product storage tank, respectively. A booster compressor is installed on the connecting pipe between the circulating flue gas outlet of the dust removal and desulfurization unit and the methanation unit. The process includes the following steps: (1) The photovoltaic power generation device produces green electricity to provide power to the air separation unit and the water electrolysis hydrogen production unit; the air separation unit uses the green electricity provided by the photovoltaic power generation device as power to produce oxygen and nitrogen. The oxygen is sent to the mixer, and the nitrogen is partially depressurized and sent to the tin bath of the glass furnace as protective gas. The rest is sold externally; the water electrolysis hydrogen production unit uses the green electricity provided by the photovoltaic power generation device as power to produce hydrogen and oxygen. The hydrogen is sent to the methanation unit, and the oxygen is depressurized and sent to the mixer. (2) The mixer mixes the oxygen from the air separation unit and the water electrolysis unit with the circulating flue gas from the glass furnace into carbon-based oxygen-enriched gas, which is used as a combustion aid for the glass furnace. (3) The methanation unit reacts the hydrogen from the water electrolysis hydrogen production unit and the circulating flue gas from the dust removal and desulfurization unit with the methanation reaction, and the generated methane (containing saturated water vapor) is sent to waste heat boiler I. (4) Waste heat boiler I recovers the waste heat of methane (containing saturated steam) from the methanation unit and produces steam as a by-product; the steam is sold externally, and the methane (containing saturated steam) after waste heat recovery is depressurized and sent to the reforming unit. (5) The reforming unit reacts the methane (containing saturated steam) from the waste heat boiler I with a portion of the circulating flue gas from the glass furnace with a methane reforming reaction. The circulating flue gas from the glass furnace enters the reforming unit in two paths. One path enters a heat storage cell on one side of the reforming unit to provide heat to the heat storage cell. In the next round, the heat storage cell will provide heat to the raw gas of the reforming unit. After heat exchange, the circulating flue gas is depressurized and sent to the dust removal and desulfurization unit. The other path and the methane (containing saturated steam) from the waste heat boiler I are sent to the heat storage cell on the other side of the reforming unit. The heat storage cell has been heated by the circulating flue gas in the previous round. The two heat storage cells work in rotation and are heated by the heat of the heat storage cell. Under certain pressure and certain catalyst, methane, carbon dioxide and steam undergo a methane reforming reaction in the reaction bed of the reforming unit to generate carbon monoxide and hydrogen, which are sent to the glass furnace as fuel. (6) The glass furnace uses carbon monoxide and hydrogen from the reforming unit as fuel and carbon-based oxygen-enriched gas from the mixer as combustion aid to produce glass melt. The carbon-based oxygen-enriched gas from the mixer first passes through a heat storage cell on one side of the glass furnace. This heat storage cell has been heated by the previous round of circulating flue gas. The two heat storage cells work alternately and are heated to a certain temperature before being sent into the glass furnace. After a certain period of circulation and enrichment, the carbon dioxide concentration of the flue gas from the glass furnace reaches equilibrium. The circulating flue gas is divided into two paths. One path passes through the heat storage cell on the other side of the glass furnace, providing heat to the heat storage cell. In the next cycle, the heat storage cell provides heat to the carbon-based oxygen-enriched gas sent by the mixer. After heat exchange, the circulating flue gas in this path is pressurized and sent to the mixer and waste heat boiler II. The other path does not pass through the heat storage cell of the glass furnace and is pressurized before being sent to the reforming unit. (7) Waste heat boiler II recovers the waste heat from the circulating flue gas sent from the glass kiln and produces steam as a by-product; Steam is sold externally, and the recycled flue gas after waste heat recovery is sent to the dust removal and desulfurization unit. (8) The dust removal and desulfurization unit removes dust and desulfurizes the circulating flue gas sent from the waste heat boiler II; after dust removal and desulfurization, part of the circulating flue gas is pressurized and sent to the methanation unit, and the rest is cooled and sold as carbon dioxide products. In the initial stage, the glass furnace uses natural gas as fuel and air as a combustion aid. After flue gas is generated, carbon-based oxygen-enriched gas, which is mixed with oxygen produced by the air separation unit and the water electrolysis hydrogen production unit, gradually replaces air for combustion. After a certain period of circulation and enrichment, the carbon dioxide concentration in the circulating flue gas reaches equilibrium, and the methanation unit, reforming unit, waste heat boiler I, waste heat boiler II, and dust removal and desulfurization unit are all put into use, and the system enters normal operation.

2. The zero-carbon glass furnace process according to claim 1, characterized in that, Step (1) The oxygen produced by the air separation unit has a purity of 99.6% or higher, is at room temperature, and has a pressure of 0.2-0.3 MPa. The oxygen is sent to the mixer. The nitrogen produced has a purity of 99.9% or higher, is at room temperature, and has a pressure of 0.2-0.3 MPa. Part of the nitrogen is depressurized to 0.05 MPa and sent to the tin bath of the glass furnace as a protective gas. The rest is sold externally. The hydrogen produced by the water electrolysis hydrogen production unit has a purity of over 99.8% (v%), a temperature of 90–100℃, and a pressure of 2.5–3.0 MPa. The hydrogen is sent to the methanation unit. The oxygen produced has a purity of over 99.0% (v%), a temperature of 90–100℃, and a pressure of 2.5–3.0 MPa. The oxygen is depressurized to 0.2–0.3 MPa and then sent to the mixer.

3. The zero-carbon glass furnace process according to claim 1, characterized in that, Step (2): The oxygen supplied by the air separation unit has a purity of 99.6% or higher, is at room temperature, and has a pressure of 0.2-0.3 MPa. The oxygen supplied by the water electrolysis unit has a purity of 99.0% or higher, a temperature of 90-100℃, and a pressure of 0.2-0.3 MPa. The carbon dioxide concentration of the circulating flue gas supplied by the glass furnace is 95.0% or higher, a temperature of 550-650℃, and a pressure of 0.15-0.25 MPa. The oxygen supplied by the air separation unit, the oxygen supplied by the water electrolysis hydrogen production unit, and the circulating flue gas supplied by the glass furnace are adjusted by regulating valves. The carbon-based oxygen-enriched mixture has a content of 21-30% v%, a temperature of 460-480℃, and a pressure of 0.05-0.10 MPa. The oxygen concentration is adjusted according to the requirements of different glass furnaces.

4. The zero-carbon glass furnace process according to claim 1, characterized in that, Step (3) The hydrogen from the water electrolysis hydrogen production unit has a purity of 99.8% or higher, a temperature of 90-100℃, and a pressure of 2.5-3.0MPa. The circulating flue gas from the dust removal and desulfurization unit has a carbon dioxide concentration of 95.0% or higher, a temperature of 250-300℃, and a pressure of 2.5-3.0MPa. The two are fed into the methanation unit at a volume ratio of H2:CO2 = 4:

1. Under the action of the nickel-based methanation catalyst, hydrogen and carbon dioxide are catalytically converted into methane, releasing a large amount of heat. The generated methane has a purity of 94.0% or higher (calculated as dry gas), a temperature of 390-410℃, and a pressure of 2.5-3.0MPa. The methane (containing saturated water vapor) is sent to waste heat boiler I.

5. The zero-carbon glass furnace process according to claim 1, characterized in that, Step (4) The temperature of the methane (containing saturated water vapor) sent from the methanation unit is 390-410℃. After the waste heat is recovered by the waste heat boiler I, the temperature is reduced to 240-260℃, and 1.5MPa steam is produced as a by-product for external sale. The methane (containing saturated water vapor) after waste heat recovery is depressurized to 0.5-1.0MPa and then sent to the reforming unit.

6. The zero-carbon glass furnace process according to claim 1, characterized in that, Step (5) The methane (containing saturated water vapor) sent from waste heat boiler I has a methane purity of over 94.0 v% (calculated as dry gas), a temperature of 240–260℃, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace has a carbon dioxide concentration of over 95.0 v%, a temperature of 1300–1400℃, and a pressure of 0.5–1.0 MPa. The circulating flue gas from the glass furnace enters the reforming unit in two paths. One path enters a heat storage cell on one side of the reforming unit to provide heat to that heat storage cell. In the next cycle, that heat storage cell provides heat to the raw gas of the reforming unit. After heat exchange, the temperature of the circulating flue gas decreases to 250–300℃, and the pressure is reduced to 0.1–0.2 MPa. The gas is then sent to the dust removal and desulfurization unit. Another route, using methane (containing saturated steam) from waste heat boiler I, feeds it into a heat storage cell on the other side of the reforming unit at a CH4:CO2 volume ratio of 2:

1. This heat storage cell has already been heated by the previous cycle of circulating flue gas. The two heat storage cells work alternately, and the gas is heated to 900–1000°C by the heat exchanger. In the reaction bed of the reforming unit, under a pressure of 0.5–1.0 MPa and with the action of a nickel-based catalyst, methane, carbon dioxide, and steam undergo a methane reforming reaction to produce carbon monoxide and hydrogen, with a CO:H2 volume ratio of approximately 3:

5. The outlet temperature is 700–800°C, and the pressure is 0.5–1.0 MPa, which is then used as fuel for the glass furnace.

7. The zero-carbon glass furnace process according to claim 1, characterized in that, Step (6) The reformer sends carbon monoxide and hydrogen, with a CO:H2 volume ratio of about 3:5, a temperature of 700-800℃, and a pressure of 0.5-1.0MPa. The mixer sends carbon-based oxygen-enriched gas with an oxygen content of 21-30v%, a temperature of 460-480℃, and a pressure of 0.05-0.10MPa. The carbon-based oxygen-enriched gas sent by the mixer first passes through a heat storage cell on one side of the glass furnace. This heat storage cell has been heated by the previous round of circulating flue gas. The two heat storage cells work alternately. After being heated to 700-800℃, it is sent into the glass furnace. The volume ratio of fuel to combustion aid is approximately 1:

2. In the glass furnace, carbon monoxide and hydrogen undergo a combustion reaction under the oxygen-enriched carbon-based combustion aid, providing heat for the glass furnace to produce molten glass. After 3-5 hours of circulation and enrichment, the carbon dioxide concentration in the glass furnace reaches equilibrium, exceeding 95.0% v%, with a temperature of 1300-1400℃ and a pressure of 0.01-0.05 MPa. The circulating flue gas is divided into two paths. One path passes through a heat storage cell on the other side of the glass furnace, providing heat to that cell. In the next cycle, this heat storage cell provides heat to the carbon-based oxygen-enriched gas from the mixer. After heat exchange, the circulating flue gas in this path is cooled to 550-650℃ and pressurized to 0.15-0.25 MPa before being sent to the mixer and waste heat boiler II. The other path does not pass through the glass furnace heat storage cell, maintaining a temperature of 1300-1400℃ and a pressure of 0.5-1.0 MPa before being sent to the reforming unit.

8. The zero-carbon glass furnace process according to claim 1, characterized in that, Step (7) The circulating flue gas from the glass kiln has a carbon dioxide concentration of over 95.0% and a temperature of 550-650℃ and a pressure of 0.15-0.25MPa. After being recovered by the waste heat boiler II, the temperature is reduced to 250-300℃ and the pressure is 0.1-0.2MPa. It also produces 1.5-4.0MPa steam as a byproduct, which is sold externally. The circulating flue gas after waste heat recovery is sent to the dust removal and desulfurization device.

9. The zero-carbon glass furnace process according to claim 1, characterized in that, The dust removal and desulfurization device consists of two parts: a high-temperature dust collector and a dry desulfurization device. The high-temperature dust collector uses cyclone separation for dust removal, and the dry desulfurization equipment uses zinc oxide desulfurization. Step (8) The circulating flue gas first passes through the high-temperature dust collector in the dust removal and desulfurization device to remove dust, and then passes through the dry desulfurization equipment in the dust removal and desulfurization device to remove hydrogen sulfide; the circulating flue gas sent from the waste heat boiler II has a carbon dioxide concentration of more than 95.0 v%, a temperature of 250-300℃, and a pressure of 0.1-0.2 MPa. The circulating flue gas after dust removal and desulfurization has a carbon dioxide concentration of more than 95.0 v%, a temperature of 250-300℃, and a pressure of 0.05-0.10 MPa. Part of it is pressurized to 2.5-3.0 MPa and sent to the methanation device, and the rest is cooled down and sold as carbon dioxide products.

10. The zero-carbon glass furnace process according to claim 1, characterized in that, In the initial stage, the glass furnace uses natural gas as fuel and air as a combustion aid. After flue gas is generated, carbon-based oxygen-enriched gas, which is mixed with oxygen produced by the air separation unit and the water electrolysis hydrogen production unit, gradually replaces the air for combustion. After 3 to 5 hours of circulation and enrichment, the carbon dioxide concentration in the circulating flue gas reaches equilibrium, with a carbon dioxide concentration of over 95.0% v%. The methanation unit, reforming unit, waste heat boiler I, waste heat boiler II, and dust removal and desulfurization unit are all put into use, and the system enters normal operation.

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