Study On Catalyst For De-arsenic Of Naphtha

Arsenic removal catalysts by hydrogenation were prepared using modified aluminum as carrier, metallic Mo-Ni as active components. It was prepared by impregnating transition metals on the matrix. Catalytic performance was evaluated on 15mL and 100mL hydrogenation laboratory test units respectively. Operating conditions for catalytic de-arsenic were optimized and adaptability of different feed oil, preparation repeatability and arsenic–tolerance ability of the catalyst for de-arsenic were studied. The de-arsenic catalyst were characterized by BET and Py-IR. The study on catalyst for de-arsenic based on modified alumina carrier revealed that de-arsenic activity of catalyst for de-arsenic based on modified carrier was much better than that of catalyst based on unmodified carrier. Under the following operating conditions: pressure of 2.0 MPa, hydrogen oil volume ratio of 100:1, volume space velocity of 5.0 h-1, operating bed temperature of 220℃～260℃, using Daqing atmospheric overhead oil, Daqing refining & chemical company naphtha and atmospheric overhead coker naphtha mixed oi(l1:1)as feed oil. The catalyst has excellent de-arsenic performance, the de-arsenic rate is more than 90% and arsenic in the product can be less than 20μg/g, that is the de-arsenic product can be well meet the need of feedstock for ethylene production by a steam cracker. Moreover, the de-arsenic catalyst has passed 1500h activity stability test and it's arsenic–tolerance is more than 7.0% . Pilot scale test lab preparation catalyst for de-arsenic was conducted, the results showed that de-arsenic activity, arsenic–tolerance performance and activity stability repeated laboratory test results, preparation repeatability of catalyst for de-arsenic was much better, pilot scale process was successful. Evaluation test showed that hydrogenation de-arsenic activity was better than that of reference catalyst,which is the best domestic naphtha hydrogenation catalyst for de-arsenic and realized commercial application on Daqing 300kt/a naphtha hydrogenation unit in 1998, when temperature was much lower, catalytic performance was as good as domestic reference catalyst. We solved naphtha hydrogenation catalyst for de-arsenic Mo-Ni co-impregnation solution preparation process problems, so industrial production and commercial application of this catalyst for de-arsenic will become a reality, it can be used on catalytic reforming naphtha de-arsenic unit in refining plant.