Ring-opening of decalin - Kinetic modelling

Upgrading of the low-quality feedstocks into high-quality diesel fuel fractions by hydrogenation combined with ring-opening of naphthenes offers a new possibility to improve the diesel fuel properties. Decalin was selected as a probe molecule for dinaphthenes that would be present in refinery streams after hydrogenation of aromatic refinery fractions. The experiments aimed at ring-opening of decalin were performed in a batch reactor by using a platinum-modified zeolite Beta. A wide range of reaction conditions (1-6 MPa, 476-563 K, and catalyst concentration 10-40 g/l) was covered in the experiments. It was observed that decalin was converted into three major product groups, namely skeletal isomers of decalin, as well as ring-opening and cracking products, in several consecutive reaction steps. A mechanism was proposed for the ring-opening of decalin on platinum-modified zeolite Beta. A kinetic model was derived, based on the elementary reaction steps of the mechanism and the values of the parameters of the model were estimated. A comparison of the model. predictions and the experimentally obtained data showed that the model was able to describe well the experimental data in the whole range of experimental conditions. Moreover, the precision of the estimated parameters was good as most of the parameter standard errors were less than 10%. The model can be thus used to optimize the experimental conditions to maximize the yields of ring-opening products. (C) 2008 Elsevier Ltd. All rights reserved.