Zero-carbon glass furnace process

A zero-carbon glass furnace process, wherein a system required for the process comprises a photovoltaic power generation unit, an air separation unit, a water electrolysis hydrogen production unit, a mixer, a methanation unit, a first waste heat boiler, a reforming unit, a glass furnace, a second waste heat boiler, and a dedusting and desulfurization unit;

• wherein
• the photovoltaic power generation unit is configured to produce green electricity to supply electricity to the air separation unit and the water electrolysis hydrogen production unit;
• the air separation unit is configured to produce oxygen and nitrogen;
• the water electrolysis hydrogen production unit is configured to produce hydrogen and oxygen;
• the mixer is configured to mix the oxygen from the air separation unit, the oxygen from the water electrolysis hydrogen production unit, and circulating flue gas from the glass furnace into carbon-based enriched oxygen;
• the methanation unit is configured to methanize the hydrogen from the water electrolysis hydrogen production unit and circulating flue gas from the dedusting and desulfurization unit;
• the first waste heat boiler is configured to recover waste heat of methane containing saturated water vapor from the methanation unit and by-produce steam;
• the reforming unit is configured to subject the methane containing saturated water vapor from the first waste heat boiler and a portion of the circulating flue gas from the glass furnace to a methane reforming reaction;
• the glass furnace is configured to produce molten glass using carbon monoxide and hydrogen from the reforming unit as fuel and the carbon-based enriched oxygen from the mixer as a combustion aid;
• the second waste heat boiler is configured to recover waste heat of the circulating flue gas from the glass furnace and by-produce steam;
• the dedusting and desulfurization unit is configured to dedust and desulfurize circulating flue gas from the second waste heat boiler;
• the photovoltaic power generation unit is connected to the air separation unit and the water electrolysis hydrogen production unit, respectively;
• a nitrogen outlet of the air separation unit is connected to a tin bath of the glass furnace and to a nitrogen product storage tank, respectively, and a pressure reducing valve is provided on a connecting pipe between the nitrogen outlet of the air separation unit and the tin bath of the glass furnace;
• an oxygen outlet of the air separation unit and an oxygen outlet of the water electrolysis hydrogen production unit are both connected to the mixer, a pressure reducing valve is provided on a connecting pipe between the oxygen outlet of the water electrolysis hydrogen production unit and the mixer, a connecting pipe between the oxygen outlet of the air separation unit, the oxygen outlet of the water electrolysis hydrogen production unit, and the mixer is provided with a flow detector, a temperature detector, a pressure detector, an oxygen purity detector, and a flow regulating valve;
• a hydrogen outlet of the water electrolysis hydrogen production unit is connected to the methanation unit;
• a carbon-based enriched oxygen outlet of the mixer is switchably connected to a heat storage grid A/B of the glass furnace and then connected to the glass furnace;
• a methane outlet of the methanation unit is connected to the first waste heat boiler;
• a methane outlet of the first waste heat boiler is switchably connected to a heat storage grid A/B of the reforming unit and then connected to the reforming unit, a pressure reducing valve is provided on a connecting pipe between the methane outlet of the first waste heat boiler and the heat storage grid A/B of the reforming unit, and a steam outlet of the first waste heat boiler is connected to a steam utilizer;
• a carbon monoxide and hydrogen outlet of the reforming unit is connected to the glass furnace;
• one of circulating flue gas outlets of the glass furnace is switchably connected to the heat storage grid B/A of the glass furnace and then connected to the second waste heat boiler and the mixer, one of the circulating flue gas outlets of the glass furnace is switchably connected to the heat storage grid A/B of the reforming unit and then connected to the reforming unit, and one of the circulating flue gas outlets of the glass furnace is switchably connected to a heat storage grid B/A of the reforming unit and then connected to the dedusting and desulfurization unit, respectively, a pressure booster is provided on a connecting pipe between the heat storage grid B/A of the glass furnace, the second waste heat boiler, and the mixer, a connecting pipe between the heat storage grid B/A of the glass furnace and the mixer is provided with a flow detector, a temperature detector, a pressure detector, a carbon dioxide purity detector, and a flow regulating valve, a pressure booster is provided on the connecting pipe between the glass furnace, the heat storage grid A/B of the reforming unit, and the heat storage grid B/A of the reforming unit, and a pressure reducing valve is provided on a connecting pipe between the heat storage grid B/A of the reforming unit and the dedusting and desulfurization unit;
• a circulating flue gas outlet of the second waste heat boiler is connected to the dedusting and desulfurization unit;
• circulating flue gas outlets of the dedusting and desulfurization unit are connected to the methanation unit and a carbon dioxide product storage tank, respectively, and a pressure booster is provided on a connecting pipe between one of the circulating flue gas outlets of the dedusting and desulfurization unit and the methanation unit;
• the process comprising operations of:
• (1) the photovoltaic power generation unit producing the green electricity to supply the electricity for the air separation unit and the water electrolysis hydrogen production unit;
• the air separation unit producing the oxygen and the nitrogen with the green electricity supplied by the photovoltaic power generation unit as the electricity, wherein the oxygen is fed into the mixer, a portion of the nitrogen is depressurized and then fed into the tin bath of the glass furnace as protective gas, and the rest is sold outside;
• the water electrolysis hydrogen production unit producing the hydrogen and the oxygen with the green electricity supplied by the photovoltaic power generation unit as the electricity, wherein the hydrogen is fed into the methanation unit, and the oxygen is fed into the mixer after depressurization;
• (2) the mixer mixing 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 into the carbon-based enriched oxygen, and using the carbon-based enriched oxygen as the combustion aid for the glass furnace;
• (3) the methanation unit methanizing the hydrogen from the water electrolysis hydrogen production unit and the circulating flue gas from the dedusting and desulfurization unit to produce the methane containing saturated water vapor, and feeding the methane containing saturated water vapor into the first waste heat boiler;
• (4) the first waste heat boiler recovering the waste heat of the methane containing saturated water vapor from the methanation unit and by-producing the steam;
• selling the steam externally, and feeding depressurized methane containing saturated water vapor after waste heat recovery into the reforming unit;
• (5) the reforming unit subjecting the methane containing saturated water vapor from the first waste heat boiler and the portion of the circulating flue gas from the glass furnace to the methane reforming reaction;
• the circulating flue gas from the glass furnace entering into the reforming unit in two ways, one way entering into a heat storage grid of one side of the reforming unit, providing heat for the heat storage grid of the one side of the reforming unit to provide heat for raw gas of the reforming unit in a next round, and after heat exchange, the circulating flue gas being depressurized and fed into the dedusting and desulfurization unit;
• the other way entering into a heat storage grid on the other side of the reforming unit along with the methane containing saturated water vapor from the first waste heat boiler, the heat storage grid on the other side of the reforming unit being already heated by the circulating flue gas of a previous round, two sides of the heat storage grids working in rotation, and the raw gas fed into the reforming unit being heated by heat of the heat storage grid on the other side of the reforming unit, in a reaction bed of the reforming unit, under a certain pressure and a certain catalyst, methane, carbon dioxide, and water vapor undergoing the methane reforming reaction to produce the carbon monoxide and the hydrogen, and feeding the carbon monoxide and the hydrogen into the glass furnace as the fuel;
• (6) the glass furnace producing the molten glass using the carbon monoxide and the hydrogen from the reforming unit as the fuel and the carbon-based enriched oxygen from the mixer as the combustion aid;
• the carbon-based enriched oxygen from the mixer first passing through a heat storage grid on one side of the glass furnace, the heat storage grid on the one side of the glass furnace being already heated by the previous round of the circulating flue gas, two sides of the heat storage grids working in rotation, and the carbon-based enriched oxygen from the mixer being heated to a certain temperature and then fed into the glass furnace;
• after the flue gas of the glass furnace being circularly enriched for a certain period of time, a carbon dioxide concentration reaching an equilibrium;
• the circulating flue gas being divided into two ways, one way passing through a heat storage grid on the other side of the glass furnace, providing heat for the heat storage grid on the other side of the glass furnace to provide heat for the carbon-based enriched oxygen from the mixer in the next round, and after heat exchange, the circulating flue gas of this way being pressurized and fed into the mixer and the second waste heat boiler;
• the other way not passing through the heat storage grid of the glass furnace, and being pressurized and fed into the reforming unit;
• (7) the second waste heat boiler recovering the waste heat of the circulating flue gas from the glass furnace and by-producing the steam;
• selling the steam externally, and feeding the circulating flue gas after waste heat recovery into the dedusting and desulfurization unit;
• and
• (8) the dedusting and desulfurization unit dedusting and desulfurizing the circulating flue gas from the second waste heat boiler;
• pressurizing a portion of circulating flue gas after dedusting and desulfurizing and feeding pressurized circulating flue gas into the methanation unit, and selling the rest externally after cooled down as carbon dioxide products;
• wherein in an initial stage, the glass furnace uses natural gas as the fuel and air as the combustion aid, and after flue gas is produced, the carbon-based enriched oxygen mixed by the flue gas, the oxygen produced by the air separation unit, and the oxygen produced by the water electrolysis hydrogen production unit gradually replaces the air and is used as the combustion aid, after a certain period of cyclic enrichment, the carbon dioxide concentration of the circulating flue gas reaches the equilibrium, and the methanation unit, the reforming unit, the first waste heat boiler, the second waste heat boiler, and the dedusting and desulfurization unit are put into operation, and the system enters into a normal operation state.