NExCC((TM)) -novel short contact time catalytic cracking technology

The demand for reformulated gasoline requires extending the flexibility of cracking operations to maximise the yield of light olefins and aromatics, b oth of which are to be used as building blocks for petrochemicals. Olefins are widely used for producing alkylates and oxygenates for the gasoline poo l while aromatics are suitable for producing a large number of organic inte rmediates and chemicals. Fluid catalytic cracking combined with various hyd rorefining technologies will be the main means used to meet the coming chal lenges for the refining industry. Demand for a short and exact contact time, higher temperature and a high ca talyst/oil ratio, to produce more light olefins, has led to a new NExCC (TM ) process incorporating a totally new reactor type. The NExCC (TM) design m akes it possible to construct large equipment with a small height-to-diamet er ratio. Compared to the conventional FCC, the NExCC (TM) product spectrum is much m ore olefinic. The process produces a higher conversion and less heavy compo nents (> 221 degreesC). In a suitable setting NExCC (TM) can also serve as a source of increased propylene production. The gas velocity in a NExCC (TM) reactor is lower than in a FCCU riser. The flow type in the regenerator is totally different compared with that of th e FCC and the reaction time is shorter. The NExCC (TM) process utilises multi-entry cyclones for separating catalys t from gas flows both in the reactor and the regenerator. The separation ef ficiency of the multi-entry cyclone is usually better than that of a conven tional cyclone, and it is optimal for handling gas flows with high particle concentrations, such as in the NExCC (TM) process. Fortum Oyj has been developing multi-entry cyclone technology by using cold and hot model tests with different testing units and by using computationa l fluid dynamics (CFD) for analysis test results and for detailed cyclone d esign. For a scale-up of the process, models which predict with reasonable accurac y the flow field and chemical reactions both in the risers and the cyclones are required. In order to study the effect of the reactor operation condit ions on the product yields and the product quality a kinetic model has been developed. The model takes into account the gasoline PONA-composition and includes eight product lumps with eight cracking reactions. A micro scale pulse reactor has been developed to obtain the parameters for the kinetic model.