US3903243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for impurity removal in a wet lime-gypsum process exhaust desulfurization equipment
Assignee: Mitsubishi Heavy Industries Ltd
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Filing: 1972-11-22
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Granted: 1975-09-02
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Expires: 1992-11-22
Abstract
Abstract A method for impurity removal in a wet lime-gypsum process exhaust desulfurization equipment wherein sulfur oxide is removed, with the aid of a lime slurry solution as absorbent, from sulfur oxide-containing gas cooled and dedusted in a cooling tower, which comprises the steps of supplying the solution obtained by filtering out by-product gypsum from the resulting gypsum slurry to the cooling tower as the cooling and dedusting medium, thereby collecting the dust from the gas, extracting a part of the cooling medium and a part of the lime slurry solution and mixing them together, and thereby removing impurities from the mixed solution.
Inventors
- 👤 Masumi Atsukawa
- 👤 Hiroyuki Ushio
- 👤 Masaaki Yanagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:40
CPC Classifications
C; C01; C01F; C01F11/00; C01F11/46; C01F11/464; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; C02; C02F; C02F1/00; C02F1/52; C02F1/5236; C02F2101/00; C02F2101/10; C02F2101/20; C02F2103/00; C02F2103/18
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
136 words
IN A METHOD FOR PRODUCING GYPSUM BY THE WET LIME GYPSUM PROCESS WHEREIN A SULFUR DIOXIDE CONTAINING DESULFURIZATION EXHAUST GAS IS COOLED AND DEDUSTED, PASSED IN CONTACT WITH A LIME SLURRY ABSORBENT SOLUTION CONTAINING METALLIC IMPURITIES ORIGINATING FROM THE LIME TO ABSORB THE SULFUR DIOXIDE THEREFROM, AND THE OBSORBENT SOLUTION IS THEN OXIDIZED TO PRODUCE A GYPSUM SLURRY FROM WHICH THE GYPSUM IS SEPARATED BY FILTRATION, THE IMPROVEMENT WHICH COMPRISES: A. USING THE FILTRATE FROM THE SEPARATION OF THE GYSPUM AS A COOLING AND DEDUSTING MEDIUM FOR THE GAS BY PASSING THE FILTRATE IN CONTACT WITH SAID GAS, B. MIXING A PART OF THE SOLUTION FROM STEP (A) WITH THE LIME SLURRY TO PRECIPITATE THE METALLIC IMPURITIES RETAINED IN THE SOLUTION AND THEREBY PURIFY IT, AND C. USING THE PURIFIED SOLUTION TO PREPARE THE LIME SLURRY.
Claim 2
Dependent Claim
136 words
IN A METHOD FOR PRODUCING GYPSUM BY THE WET LIME GYPSUM PROCESS WHEREIN A SULFUR DIOXIDE CONTAINING DESULFURIZATION EXHAUST GAS IS COOLED AND DEDUSTED, PASSED IN CONTACT WITH A LIME SLURRY ABSORBENT SOLUTION CONTAINING METALLIC IMPURITIES ORIGINATING FROM THE LIME TO ABSORB THE SULFUR DIOXIDE THEREFROM, AND THE OBSORBENT SOLUTION IS THEN OXIDIZED TO PRODUCE A GYPSUM SLURRY FROM WHICH THE GYPSUM IS SEPARATED BY FILTRATION, THE IMPROVEMENT WHICH COMPRISES: A. USING THE FILTRATE FROM THE SEPARATION OF THE GYSPUM AS A COOLING AND DEDUSTING MEDIUM FOR THE GAS BY PASSING THE FILTRATE IN CONTACT WITH SAID GAS, B. MIXING A PART OF THE SOLUTION FROM STEP (A) WITH THE LIME SLURRY TO PRECIPITATE THE METALLIC IMPURITIES RETAINED IN THE SOLUTION AND THEREBY PURIFY IT, AND C. USING THE PURIFIED SOLUTION TO PREPARE THE LIME SLURRY.
Claim 3
Dependent Claim
29 words
The method of claim 1 wherein supernatant liquid is removed from the gypsum slurry prior to the filtration and the supernatant is also used to prepare the lime slurry.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |