Pt-Sn-K-Mg/Al2O3 catalysts for the dehydrogenation of long chain paraffins (n-C-10(0)-C-13(0)) were successfully developed and applied in the industry. The catalysts were tested on both the industrial side fixed bed reactor and the industrial PACOL dehydrogenation plant. The industrially deactivated Pt-Sn-K-Mg/Al2O3 catalysts were characterized by TG-DTA, elemental analysis, UV Raman spectroscopy, TPO, SEM, XRD, BET, MIP and CO-chemisorption. The industrial 72-day-run dada indicated that Pt-Sn-K-Mg/Al2O3 catalysts performed excellent dehydrogenation conversion of 11.6% and high mono-olefin selectivity of 94.1%. The daily output of alkylbenzene over Pt-Sn-K-Mg/Al2O3 catalysts was as high as 333.6 ton/day. The deactivated catalysts were deposited by the amorphous and graphitized coke, of which the weight percentage was 3.78% and the H/C mole ratio was 1.19. The coke covered parts of the Pt and support surface, while the pore and crystalline structure of the catalysts were not destroyed. (C) 2015 Elsevier B.V. All rights reserved.