Computational fluid dynamics‐based optimization of dimpled steam cracking reactors for reduced CO 2

Spherical dimples in cylindrical tubes enhance heat transfer and lead to a more uniform radial temperature profile. To combine these positive properties with a low pressure drop, a single dimple was optimized through a genetic algorithm. Multiple design parameters such as width, height, and curvature of the dimple were investigated. Heart-shaped dimples outperformed spherical dimples. Three-dimensional reactive simulations of a Millisecond propane steam cracking reactor showed that both the spherically dimpled and the heart-shaped dimpled coil positively affect the light olefin selectivity, mainly through an increase in propylene selectivity. The optimized dimples could reduce the high pressure drop penalty by 21%. Run length simulations proved that the optimized dimple shape results in an additional run length extension of 18%. Next to this, the fuel rate consumption can be decreased by 6% compared to a bare coil, which could theoretically result in 4% less CO2 emissions

Effects of insularity on digestion: living on islands induces shifts in physiological and morphological traits in island reptiles

“The final publication is available at Springer via http://dx.DOI: 10.1007/s00114-015-1301-8