System and process for oxy-fuel calcination of lime-bearing sludge
The disclosure generally provides a modification of a calcination process of lime bearing sludge in such a way that the flue gas generated by the calcination process contains primarily carbon dioxide and water vapor along with only minor amounts of other gaseous species. Such a flue gas can be treated by standard industrial gas scrubbing and purification processes to remove residual particulate solids, to condense and remove the water vapor as liquid water, and further treatment to produce essentially pure carbon dioxide. The resulting product may be used for purposes that do not involve a net emission of carbon dioxide to the atmosphere, thereby reducing environmental harm. Such purified carbon dioxide may be used in industry for enhanced oil recovery (EOR) processes, synthetic fuels production, carbonated beverage production, pharmaceutical production, or other beneficial uses.
1 . A calcination system for lime-bearing sludge, comprising:
a mixer arranged to mix the lime-bearing sludge with a relatively drier lime-bearing sludge to produce a mixed lime-bearing sludge;
an impact mill dryer coupled to the mixer to receive the mixed lime-bearing sludge and disperse the mixed lime-bearing sludge into dried lime-bearing sludge solids for mixing with a transportation gas;
a cyclone coupled to the mill to receive the dried lime-bearing sludge solids and the transportation gas to at least partially separate the dried lime-bearing sludge solids from the transportation gas and form a gas of primarily carbon dioxide as a product;
a lime mud feeder coupled to the cyclone to receive the dried lime-bearing sludge solids from the cyclone;
a calciner coupled to the lime mud feeder to receive the dried lime-bearing sludge solids from the lime mud feeder to calcinate in a chamber containing a percentage of oxygen greater than atmospheric air, the calciner being at least partially sealed from atmospheric air and having a hydrocarbon fuel supply coupled to the calciner;
a gas conditioning chamber sealed from air intrusion and arranged to receive calciner exhaust gas from the calciner and add heat to the calciner exhaust gas;
an oxygen supply having a majority percentage of oxygen coupled to a burner of the gas conditioning chamber;
a carbon dioxide supply having a majority percentage of carbon dioxide coupled to the burner of the gas conditioning chamber;
a hydrocarbon fuel supply coupled to the burner of the gas conditioning chamber; and
at least one water spray to inject water into the gas conditioning chamber to cool the calciner exhaust gas via evaporation;
wherein the calciner exhaust gas in the gas conditioning chamber is maintainable below a threshold temperature at which particles contained in the calciner exhaust gas experience fusion or sintering by adjusting a ratio of oxygen from the oxygen supply to carbon dioxide from the carbon dioxide supply.
2 . The calcination system of claim 1 , wherein a conditioned exhaust gas stream from the gas conditioning chamber is mixable with a lime-bearing sludge for processing.
3 . The calcination system of claim 1 , further comprising a sealed feeder interposed between the mixer and the impact mill dryer to receive the mixed lime-bearing sludge from the mixer and to control a feed rate of the mixed lime-bearing sludge into the impact mill dryer.
4 . The calcination system of claim 1 , wherein the carbon dioxide supply comprises recycled carbon dioxide from a carbon dioxide stream produced from the calcination system.
5 . The calcination system of claim 1 , wherein the transportation gas is formed from a conditioned exhaust gas stream from the gas conditioning chamber.
6 . The calcination system of claim 1 , wherein the impact mill dryer is at least partially sealed from air intrusion.
7 . The calcination system of claim 1 , further comprising a wet scrubber coupled downstream of the cyclone to scrub an amount of remaining solids and water vapor from the gas of primarily carbon dioxide.
8 . A calcination system for lime-bearing sludge, comprising:
a calciner at least partially sealed from atmospheric air intrusion;
a lime-bearing sludge supply coupled to the calciner;
an oxygen supply having a percentage of oxygen greater than atmospheric air coupled to the calciner;
a hydrocarbon fuel supply coupled to the calciner;
a gas conditioning chamber sealed from air intrusion and arranged to receive calciner exhaust gas from the calciner and add heat to the calciner exhaust gas;
an oxygen supply having a majority percentage of oxygen coupled to a burner of the gas conditioning chamber;
a carbon dioxide supply having a majority percentage of carbon dioxide coupled to the burner of the gas conditioning chamber; and
a hydrocarbon fuel supply coupled to the burner of the gas conditioning chamber; and
at least one water spray to inject water into the gas conditioning chamber to cool the calciner exhaust gas via evaporation;
wherein the calciner exhaust gas in the gas conditioning chamber is maintainable below a threshold temperature at which particles contained in the calciner exhaust gas experience fusion or sintering by adjusting a ratio of oxygen from the oxygen supply to carbon dioxide from the carbon dioxide supply.
9 . The calcination system of claim 8 , further comprising a wet scrubber arranged downstream of the cyclone collection system to scrub an amount of remaining solids and water vapor from a gas of primarily carbon dioxide formed as a product by the cyclone collection system.
10 . The calcination system of claim 8 , wherein a hydrocarbon fuel supply is coupled to the calciner and the calciner includes a chamber containing a percentage of oxygen greater than atmospheric air to calcinate lime-bearing sludge received from the lime-bearing sludge supply.
11 . The calcination system of claim 8 , wherein the carbon dioxide supply comprises recycled carbon dioxide from a carbon dioxide stream produced from the calcination system.
12 . The calcination system of claim 8 , wherein a conditioned exhaust gas stream from the gas conditioning chamber is mixable with a lime-bearing sludge for processing.
13 . The calcination system of claim 8 , further comprising a mill at least partially sealed from air intrusion to receive lime-bearing sludge and mix the lime-bearing sludge with a conditioned exhaust gas stream from the gas conditioning chamber.
14 . The calcination system of claim 8 , further comprising a cyclone collection system to receive lime-bearing sludge components mixed with a conditioned exhaust gas stream from the gas conditioning chamber and separate the components and the exhaust gas.
15 . The calcination system of claim 14 , wherein an exhaust gas that is separated in the cyclone collection system comprises primarily a carbon dioxide stream.
16 . A calcination system for lime-bearing sludge, comprising:
an impact mill dryer arranged to receive the lime-bearing sludge and disperse the lime-bearing sludge into dried lime-bearing sludge solids for mixing with a transportation gas;
a cyclone coupled to the mill to receive the dried lime-bearing sludge solids and the transportation gas to at least partially separate the dried lime-bearing sludge solids from the transportation gas and form a gas of primarily carbon dioxide as a product;
a lime mud feeder coupled to the cyclone to receive the dried lime-bearing sludge solids from the cyclone;
a calciner coupled to the lime mud feeder to receive the dried lime-bearing sludge solids from the lime mud feeder to calcinate in a chamber containing a percentage of oxygen greater than atmospheric air, the calciner being at least partially sealed from atmospheric air and having a hydrocarbon fuel supply coupled to the calciner;
a gas conditioning chamber sealed from air intrusion and arranged to receive calciner exhaust gas from the calciner and add heat to the calciner exhaust gas;
an oxygen supply having a majority percentage of oxygen coupled to a burner of the gas conditioning chamber;
a carbon dioxide supply having a majority percentage of carbon dioxide coupled to the burner of the gas conditioning chamber;
a hydrocarbon fuel supply coupled to the burner of the gas conditioning chamber; and
at least one water spray to inject water into the gas conditioning chamber to cool the calciner exhaust gas via evaporation;
wherein the calciner exhaust gas in the gas conditioning chamber is maintainable below a threshold temperature at which particles contained in the calciner exhaust gas experience fusion or sintering by adjusting a ratio of oxygen from the oxygen supply to carbon dioxide from the carbon dioxide supply.
17 . The calcination system of claim 16 , further comprising a wet scrubber coupled downstream of the cyclone to scrub an amount of remaining solids and water vapor from the gas of primarily carbon dioxide.
18 . The calcination system of claim 16 , wherein the carbon dioxide supply comprises recycled carbon dioxide from a carbon dioxide stream produced from the calcination system.
19 . The calcination system of claim 16 , wherein the transportation gas is formed from a conditioned exhaust gas stream from the gas conditioning chamber.
20 . The calcination system of claim 16 , wherein the impact mill dryer is at least partially sealed from air intrusion.