Kinetic modelling of methanol conversion to light olefins process over silicoaluminophosphate (SAPO-34) catalyst

• MTO kinetic model was established based on the simple and reliable reaction network.
• The effects of coke deposition were considered in the kinetic model.
• The secondary reactions of MTO are reduced by decreasing contact time.
• Calculation of the parameters of best fit was performed by PSO algorithm.

The MTO process over SAPO_34 catalyst was modelled with the consideration of functionality against coke deposition for products distribution, consisting of 11 reactions involving 13 reaction species and used in the assessment of experimental data acquired in a fixed bed reactor in a temperature range from 400 to 460 °C using weight hour space velocity (WHSV) of 1, 2 and 4 g MeOH g catalyst−1 h−1 and at atmospheric pressure. The results showed that olefins carbon selectivity increases with space velocity, suggesting that the secondary reactions which take part in the MTO reaction for the paraffinic components production are reduced by decreasing contact time. Calculation of the kinetic model parameters of best fit was performed by particle swarm optimization algorithm through solving the mass conservation equations of the reaction products of the kinetic scheme. Pre-exponential factors and apparent activation energies were then calculated based on the Arrhenius equation using the optimized rate constants. The kinetic model gave a good representation of MTO experimental data at conditions close to industrial practice.

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