Catalytic performance and industrial test of HY zeolite for alkylation of naphthalene and α-tetradecene

Abstract

As a synthetic lubricant with excellent properties, alkyl naphthalene is widely used in petrochemical and manufacturing industries. Alkyl naphthalene is formed by naphthalene and α-tetradecene under the action of an alkylation catalyst. The activities of several solid acid catalysts (clay, sulfated zirconia and HFAU zeolite) for such alkylation were tested. Results of the test showed that the activity of the alkylation catalyst was closely related to acidity, specific surface area and pore structure. Appropriate acidity and acid amount are necessary. In addition, the selective catalysis of zeolite was favorable for alkylation. The service life of HFAU zeolite was measured under industrial conditions. The deactivation and regeneration behaviors of HFAU zeolite were studied by XRD, SEM, TG/DTG, BET and Py-IR. The results showed that the service life of fresh HFAU zeolite reached 480 hours and the conversion of naphthalene can reach 95%. After in situ regeneration, the service life reached 240 hours and the selectivity of monoalkyl naphthalene reached nearly 100%. Thus the main problem was the rapid loss of activity. According to the characterization of deactivated catalyst, the blockage of pores by amorphous coke and the covering of active sites were the main reasons for HFAU zeolite deactivation. Moreover, the strong Brønsted acid sites were first covered by coke. The activity of the deactivated catalyst can be largely restored by calcinations in the laboratory.