US4002722A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and apparatus for wet treatment of vent gas
Assignee: Sintokogio Ltd
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Filing: 1975-03-12
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Granted: 1977-01-11
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Expires: 1995-03-12
Abstract
Abstract Vent gas containing disagreeable odor components consisting mainly of phenolic substances evolving from foundries using shell molding sand containing phenol resin as a binder is efficiently wet-treated by scrubbing the vent gas with an aqueous absorbent solution, to which a ferrous salt and hydrogen peroxide are added so that a ferrous ion concentration may be at least one-seventh of a hydrogen peroxide concentration, thereby making an oxidation-reduction potential of the aqueous absorbent solution have at least a value of (540 - 60 × PH value) mV, wherein the PH value is 5 or less.
Inventors
- 👤 Hiroshi Suzuki
- 👤 Shigeru Ito
- 👤 Kazuyuki Nishikawa
- 👤 Tutomu Shibata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:48
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
120 words
A process for wet treatment of vent gas containing at least one disagreeable odor component selected from the group consisting of phenols, formaldehydes and ammonia, which comprises adding a ferrous salt and hydrogen peroxide to an aqueous absorbent solution in an absorption tower provided with an aqueous absorbent solution tank and filter layers for absorption of the disagreeable odor components, thereby making the ferrous ion concentration at least one-seventh of the hydrogen peroxide concentration in the aqueous absorbent solution, and adjusting an oxidation-reduction potential of the thus added absorbent solution at least to a value of (540 - 60 × pH value) mV, said pH value being 5 or less and contacting said vent gas with said aqueous absorbent solution.
Claim 2
Dependent Claim
120 words
A process for wet treatment of vent gas containing at least one disagreeable odor component selected from the group consisting of phenols, formaldehydes and ammonia, which comprises adding a ferrous salt and hydrogen peroxide to an aqueous absorbent solution in an absorption tower provided with an aqueous absorbent solution tank and filter layers for absorption of the disagreeable odor components, thereby making the ferrous ion concentration at least one-seventh of the hydrogen peroxide concentration in the aqueous absorbent solution, and adjusting an oxidation-reduction potential of the thus added absorbent solution at least to a value of (540 - 60 × pH value) mV, said pH value being 5 or less and contacting said vent gas with said aqueous absorbent solution.
Claim 3
Dependent Claim
23 words
A process as claimed in claim 1, comprising supplying said ferrous salt and hydrogen peroxide at a definite rate to the absorption tower.
Claim 4
Dependent Claim
29 words
A process as claimed in claim 2, comprising controlling the oxidation-reduction potential of said absorbent solution thereby reducing the amount of components, the concentration of which is substantially fluctuated.
Claim 5
Dependent Claim
35 words
A process as claimed in claim 1, comprising controlling said pH value of the absorbent solution thereby enhancing the absorption efficiency of said absorbent solution with respect to the alkaline components in the vent gas.
Claim 6
Dependent Claim
12 words
A process as claimed in claim 1, comprising recycling said absorbent solution.
Claim 7
Dependent Claim
20 words
A process as claimed in claim 5, wherein said recycling step includes filtering accumulated suspended solids in said absorbent solution.
Claim 8
Dependent Claim
22 words
A process as claimed in claim 2, wherein said ferrous salt is intermittently supplied at the definite rate to the absorption tower.
Claim 9
Dependent Claim
22 words
A process as claimed in claim 2, wherein said hydrogen peroxide is intermittently supplied at the definite rate to the absorption tower.
References Cited (Backward Citations)
US3021189A
Cited
US3905774A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-11 | 1980-07-12 | 1981-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-11 | 1984-07-12 | 1985-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-11 | 1988-07-12 | 1989-01-11 | $7700.00 | Window Closed / Lapsed |