Dry sorbent injection with recirculation
AssigneeIndustrial Accessories Company
InventorPramodh Nijhawan
Life of this patent
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Abstract
Described herein is a dry sorbent injection system and process for removing sulfur oxides from a flue gas. The process generally comprises treating the flue gas with a dry sorbent material to convert the sulfur oxides to sodium sulfate particulates. The sodium sulfate particulates may then be introduced into a mix tank with water to form sodium sulfate solution. The sodium sulfate solution may then be reacted with a calcium hydroxide slurry to produce a reaction mixture comprising calcium sulfate precipitate and a sodium hydroxide solution. The calcium sulfate (gypsum) may be recovered, and the sodium hydroxide solution may be recirculated to pre-treat the flue gas by removing at least a portion of the sulfur dioxide and/or cooling the flue gas stream.
Claims18
A process for removing sulfur oxides from a flue gas, the process comprising:
- treating the flue gas with a dry sorbent material that reacts with at least a portion of the sulfur oxides to produce sodium sulfate particulates;
- introducing the sodium sulfate particulates and water into a mix tank, and dissolving the sodium sulfate particulates in the water to form a sodium sulfate solution;
- introducing the sodium sulfate solution and a calcium hydroxide slurry into a reaction tank, and reacting at least a portion of the sodium sulfate solution with at least a portion of the calcium hydroxide slurry to produce a reaction mixture comprising a calcium sulfate precipitate and a sodium hydroxide solution;
- and
- pre-treating at least a portion of the flue gas with at least a portion of the sodium hydroxide solution to remove at least a portion of the sulfur dioxide from the flue gas before treating the flue gas with the dry sorbent material.
A process for removing sulfur dioxide from a thermal oxidizer flue gas, the process comprising:
- treating the flue gas with a dry sorbent material to recover sodium sulfate;
- reacting at least a portion of the sodium sulfate and a calcium hydroxide slurry to produce a reaction mixture comprising a solids portion comprising precipitated calcium sulfate and a liquids portion comprising sodium hydroxide solution;
- recovering the solids portion as a gypsum product, wherein the gypsum product comprises at least 99% by weight calcium sulfate;
- and
- pre-treating at least a portion of the flue gas with at least a portion of the sodium hydroxide solution to remove at least a portion of the sulfur dioxide from the flue gas before treating the flue gas with the dry sorbent material.
A process for removing sulfur dioxide from a flue gas, the process comprising:
- treating the flue gas with a dry sorbent material to recover sodium sulfate;
- reacting at least a portion of the sodium sulfate and a calcium hydroxide slurry to produce a reaction mixture comprising calcium sulfate precipitate and a sodium hydroxide solution;
- and
- pre-treating the flue gas with at least a portion of the sodium hydroxide solution to remove at least a portion of the sulfur dioxide from the flue gas before treating the flue gas with the dry sorbent material.
Dependencies are inferred from the claim text.