Catalyst – solid sorbent – or support therefor: product or process – Solid sorbent – Free carbon containing
Patent
1992-07-28
1993-12-14
Konopka, Paul E.
Catalyst, solid sorbent, or support therefor: product or process
Solid sorbent
Free carbon containing
4232391, 42324403, 95129, 95137, C01B 3110, C01B 1760, B01J 2020, B01D 5334
Patent
active
052702790
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. TECHNICAL FIELD
This invention relates to formed activated coke for SOx and NOx removal, and especially to a production process for formed activated coke for SOx and NOx removal which has a high NOx-removing ability, excellent pressure resistance, abrasion resistance and impact strength and, is in large-scale systems.
2. BACKGROUND ART
Known dry processes for removing NOx from flue gas are to decompose NOx by bringing it into contact with a metallic catalyst at high temperatures in the presence of ammonia or to decompose or adsorb NOx by causing flue gas to pass through a layer of a carbonaceous adsorbent such as activated granular carbon in the presence or absence of ammonia.
Among these processes, the process which makes use of the carbonaceous adsorbent is particularly preferred as a treatment process for a gas which also contains SOx, such as combustion flue gas, because the carbonaceous adsorbent also has excellent SOx-adsorbing ability.
These carbonaceous materials are, however, somewhat inferior in NOx-removing ability as compared to metallic catalysts. As a result, various attempts have been made to improve their NOx-removing ability.
For example, for further improving the NOx-removing ability of a carbonaceous material such as activated carbon, there are methods in which the NOx-removing ability is improved by making a carbonaceous material carry a metal such as Ti, Cr, V, Fe or Cu or by treating a carbonaceous material with an oxidizing solution such as nitric acid, sulfuric acid or hydrogen peroxide or with an oxidizing gas such as O.sub.2, O.sub.3, SO.sub.3 or NO in the presence of water vapor to oxidize and reactivate the carbonaceous material (U.S. Pat. No. 4,210,628, etc.).
Activated carbon has heretofore been used as a carbonaceous adsorbent for SOx and NOx removal. A method different from the conventional use of activated carbon has been recently developed which was formed activated coke for SOx and NOx removal with excellent results, especially in SOx- and NOx-removing ability (Japanese Patent Publication No. 1885/1987, etc.).
The specific surface area of formed activated coke for SOx and NOx removal of this type is 30 m.sup.2 /g or less, which is smaller than the specific surface area of activated carbon, and the pore distribution of the former is also different from that of the latter. Because of its high strength including high pressure resistance, abrasion resistance and impact strength, the formed activated coke for SOx and NOx removal is suited for use in the practice of a moving-bed or fluidized-bed process in an actual large-scale system while being repeatedly subjected to regeneration after adsorption. There is, however, an increasing demand for an improvement in the NOx-removing ability of above processed activated coke.
Treatment of formed activated coke for SOx and NOx removal by the process employed above for the improvement of the NOx-removing ability of activated carbon is, however, accompanied by the drawback that, where the coke is metal-bearing activated coke, the metal is converted to a sulfate by SO.sub.2 gas also contained in flue gas and the NOx-removing ability gradually decreases. Further, the oxidizing and reactivating method which makes use of an oxidizing solution has difficulty effecting activation to the interiors of pores so that the oxidizing treatment has to be repeated to significantly improve the NOx-removing activity.
In the case of oxidation and activation by an oxidizing gas, on the other hand, it is observed that activation proceeds to the interiors of pores and the NOx-removing ability can be effectively improved. The strength of the resulting activated coke has, however, been reduced, which leads to the problem that it can no longer withstand repeated use in a SOx- and NOx-removing system of the moving bed type.
It has therefore been found necessary to develop a new treatment method, which is different from those applied to conventional activated carbon, in order to improve the NOx-removing ability of the formed activated coke for SO
REFERENCES:
patent: 1731223 (1929-10-01), Brady
patent: 2992065 (1961-07-01), Feustel et al.
patent: 3502427 (1970-03-01), Johswich
patent: 3634028 (1972-01-01), Hohne
patent: 4210628 (1980-07-01), Ninomiya et al.
patent: 4492771 (1985-01-01), Hasegawa et al.
Matsufuji Yoshihiro
Ninagawa Yasuhiko
Shiraishi Ikuo
Tsuji Kazuhiko
Konopka Paul E.
Mitsui Mining Co. Ltd.
LandOfFree
Production process of formed activated coke for SOx and NOx remo does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Production process of formed activated coke for SOx and NOx remo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Production process of formed activated coke for SOx and NOx remo will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1705519