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Development and optimization of cu based catalytic materials for the simultaneous removal of sox and nox from flue gases


The general objectives of the project are :

1) to develop improved and more reliable Cu-oxide based catalytic materials for simultaneous removal of SO2 and NOx from flue gas, and

2) to develop the process itself from the labscale testing (as in previous BRITE project) to the pilot-plant proof of concept unit.
The simultaneous removal of SO2 and NOx from exhaust gas containing oxygen can be achieved with efficiencies of over 90% using a copper-on-alumina based catalytic material that in the 300-400 C temperature range is able to oxidize-adsorb the SO2 in the form of a regenerable sulphate and at the same time to catalyze the reduction of NO to N2 in the presence of NH3/O2. After saturation of the sorption capacity towards SO2 capture, the copper-on-alumina based material can be regenerated at temperatures in the 450-550 C range using a reducing agent like methane or other petrochemical side streams containing H2 or CO to form a concentred stream of SO2 (concentration higher than 30%) that is send to an unit for H2SO4 production. A sorbent-catalyst based on copper-on-alumina has been developed with suitable properties in terms of i) activity in NO conversion and efficiency in SO2 capture, ii) mechanical properties of resistance to attrition, iii) stability during the reaction-regeneration cycles, iv) form and dimensions for the industrial development, v) cost and vi) methodology of industrial production on a large scale. This sample has been tested in extended operation, determining the stable sorption and catalytic behaviour up to over 1000 of reaction-regeneration. Stable sorption and catalytic performances were also demonstrated in accelerate ageing tests (higher water and CO2 content in the feed, higher temperatures of sulphation, regeneration and reoxidation). Aged samples were also shown to maintain the original attrition resistance and crushing strength, copper profile within pellets and porosity characteristics, showing the technical possibility of industrial exploitation of this sorbent-catalyst and technology. A technico-economical fattibility study of the process, with a quantified flow-sheet of the technology and of the various apparatus, and the determination of the cost per ton of removal of SO2 and NO has been made. The results indicate the economical advantage of the technology with respect to competitive commercial technologies of separate of combined removal of SO2 and NO. Data on the kinetics of reaction and regeneration as well as on the structural, textural, reactivity and mechanical properties of the sorbent-catalyst are available.
Improved catalytic materials will be able to operate effectively in extended operations over multiple cycles of regeneration, in the presence of variable, real gas compositions (derived from the combustion of fuel oil with about 2 % S), and solid transport conditions as those prevailing in the pilot-plant unit. Removal of SO2 and NOx higher than 90 % for, at least, 100 cycles of reaction-regeneration is expected.

The principle points of the project are :

1) Sorbent - catalyst testing during extended operations over multiple cycles of reaction and regeneration, in presence of real flue gas under realistic attrition conditions.

2) Evaluation and identification of the nature of changes in the attrition resistance during Life-Cycle Test.

3) Development of improved methodologies of preparation of these catalytic materials.


Enimont Anic
Piazza Boldrini 1
20097 San Donato Milanese

Participants (4)

Rhône-Poulenc SA
25 Quai Paul Doumer
92408 Courbevoie
Società per lo Sviluppo Tecnologico dei Materiali Avanzati SpA
Via Zamboni 33
40126 Bologna
University Of Lemerick