TY - JOUR
T1 - Investigation of carbonaceous compounds deposited on NiMo catalyst used for ultra-deep hydrodesulfurization of gas oil by means of temperature-programmed oxidation and Raman spectroscopy
AU - Koizumi, Naoto
AU - Urabe, Yoshihisa
AU - Inamura, Kazuhiro
AU - Itoh, Takashi
AU - Yamada, Muneyoshi
N1 - Funding Information:
This study was supported by Industrial Technology research Program in ’04 from New Energy and Industrial Technology Development Organization (NEDO) of Japan.
PY - 2005/10/15
Y1 - 2005/10/15
N2 - NiMo/Al2O3 catalyst used for ultra-deep HDS of several gas oils at various conditions was characterized by both temperature-programmed oxidation combined with mass spectroscopy (TPO-MS) and/or gas chromatography (TPO-GC), and Raman spectroscopy to make clear how the catalyst was deactivated. TPO-MS showed the presence of carbonaceous compounds containing H and N atoms on the used catalysts. TPO-GC showed that the combustive property of the carbonaceous compounds sensitively changes depending on the HDS reaction conditions and the position of the catalyst charged in the HDS reactor. A curve fitting analysis of TPO-GC profiles indicated that the carbonaceous compounds combusted below 680 K during TPO were observed on all the spent catalysts examined here whereas more refractory carbonaceous compound (combusted at around 690 K during TPO) was observed on the catalyst that had experienced severe HDS reaction conditions. More refractory carbonaceous compound was preferentially observed on the catalyst charged near the outlet of the HDS reactor. Raman spectra of the carbonaceous compounds indicated that the carbonaceous compounds combusted below 680 K during TPO has an amorphous-like structure whereas the refractory carbonaceous compound has a graphite-like one. Raman spectra also indicated that the graphite-like carbonaceous compound possesses a greater lateral size than the amorphous-like one, implying that the refractory carbonaceous compound can cover the catalyst surface more effectively. The carbonaceous compound having a graphite-like structure is one of main reasons for the catalyst deactivation. It is suggested that the precursor for this type of carbonaceous compound is not formed directly from the feed, but indirectly formed during the HDS of gas oil, because of its preferential deposition on the catalyst charged near the outlet of the HDS reactor.
AB - NiMo/Al2O3 catalyst used for ultra-deep HDS of several gas oils at various conditions was characterized by both temperature-programmed oxidation combined with mass spectroscopy (TPO-MS) and/or gas chromatography (TPO-GC), and Raman spectroscopy to make clear how the catalyst was deactivated. TPO-MS showed the presence of carbonaceous compounds containing H and N atoms on the used catalysts. TPO-GC showed that the combustive property of the carbonaceous compounds sensitively changes depending on the HDS reaction conditions and the position of the catalyst charged in the HDS reactor. A curve fitting analysis of TPO-GC profiles indicated that the carbonaceous compounds combusted below 680 K during TPO were observed on all the spent catalysts examined here whereas more refractory carbonaceous compound (combusted at around 690 K during TPO) was observed on the catalyst that had experienced severe HDS reaction conditions. More refractory carbonaceous compound was preferentially observed on the catalyst charged near the outlet of the HDS reactor. Raman spectra of the carbonaceous compounds indicated that the carbonaceous compounds combusted below 680 K during TPO has an amorphous-like structure whereas the refractory carbonaceous compound has a graphite-like one. Raman spectra also indicated that the graphite-like carbonaceous compound possesses a greater lateral size than the amorphous-like one, implying that the refractory carbonaceous compound can cover the catalyst surface more effectively. The carbonaceous compound having a graphite-like structure is one of main reasons for the catalyst deactivation. It is suggested that the precursor for this type of carbonaceous compound is not formed directly from the feed, but indirectly formed during the HDS of gas oil, because of its preferential deposition on the catalyst charged near the outlet of the HDS reactor.
KW - Carbonaceous compound
KW - Catalyst deactivation
KW - Raman spectroscopy
KW - TPO
KW - Ultra-deep HDS
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U2 - 10.1016/j.cattod.2005.07.172
DO - 10.1016/j.cattod.2005.07.172
M3 - Conference article
AN - SCOPUS:27744496241
SN - 0920-5861
VL - 106
SP - 211
EP - 218
JO - Catalysis Today
JF - Catalysis Today
IS - 1-4
T2 - International Conference on Gas-Fuel 05 International Conference on Gas-Fuel 05
Y2 - 14 November 2005 through 16 November 2005
ER -