Optimization and scale-up of methyl ricinoleate pyrolysis reactor: A numerical simulation and experimental study

Abstract

The pyrolysis of methyl ricinoleate (MR) produces valuable intermediates, undecylenic acid methyl ester (UAME) and heptanal (HEP), essential for pharmaceutical and chemical industries. Conventional reactors are limited to poor heat transfer and significant temperature gradients, resulting in low product yields and difficulties in scale-up. To overcome these limitations, this study develops a process intensification approach using an inductively heated reactor coupled with rotational atomization feeding for MR pyrolysis. Additionally, computational fluid dynamics (CFD) and numerical heat transfer (NHT) simulations were employed to optimize the reactor structure. The CFD results demonstrated that the increasing number of fins and feed nozzle rotation speed enhanced airflow turbulence and improved droplet-wall impingement. And the NHT simulations confirmed that the uniform wall temperature distribution was achieved for the optimized reactor. Experimental results demonstrated that the conversion rate of MR increased with increasing nozzle speed, with the maximum UAME and HEP yields reaching 65.9 % and 79.6 %, respectively at 520 °C in the scaled-up reactor. Notably, the reactor exhibited minimal scale-up effects, attributed to its enhanced heat transfer and uniform temperature distribution. Overall, the pyrolysis reactor proposed in this study exhibited great potential in industrial MR pyrolysis.