Characterisation of coking activity during supercritical hydrocarbon pyrolysis

Abstract

The active cooling of the Supersonic Combustion Ramjet engine, for hypersonic flight purpose, is ensured thanks to fuel, n-dodecane for the present study. The endothermic fuel pyrolysis, starting above 800 K, could generate an unwanted coke formation. Experimental tests up to 1125 K and between 1 MPa and 6 MPa have been performed on the hydrocarbon fuel pyrolysis to evaluate the coking activity. 316L stainless steel, low carbon steel and titanium reactors have been considered. A witness of the coke formation, based on its thermal insulation and pressure loss effects, has been found. A correlation between methane production and coke deposit was found. The coke has been studied with Scanning Electron Microscope (SEM), Energy Dispersion Spectroscopy (EDS), X-ray diffractometer and Fourier Transform Infrared (FTIR) spectroscopy. The porosity, the density and the permeability of the coke have been estimated.

Fuel pyrolysis through porous media: Coke formation and coupled effect on permeability

“…inside the porous medium, and 310 pyrolytic, i.e. at the surface) as it has been studied in previous work [4]. Nevertheless, the 311 differences are too small to be quantitatively interpreted and these results should be completed …”

“…effect) and the coke formation can modify the structure's permeability [4]. As a result, the 41 coupling of heat and mass transfer is directly impacted by the chemistry and such 42 phenomenon need to be more understood.…”

High temperature and pressure reactive flows through porous media

“…For each scale, the permeability depends on several elements: the material employed (composite, metal, ceramic…), the structure morphology (tubular, plate…), the layer number (simple or multilayer composite), the layer disposition (angle between each layer, i.e. 0, 45 or 90°), the presence of cracks (their orientation, the connexion between them) (Soller 2009, Park 2003, Federico 2008, Xu 2008, Shields 2008, Gascoin 2008b, Peddiraju 2005, Kladias, Choi 1998, the aging and the damage (outer and inner cracking, delamination) (Park 2003). At the macroscale, the manufacturing process has a huge effect on the material permeability.…”

Cracking of Durene over HY and H Zeolites

“…low-density polyethylene) in a quartz semi continuous feed reactor with fast heating to obtain solid carbons [4,5]. In recent years, the thermal decomposition of hydrocarbon fuel in hypersonic aircrafts is also a research hotspot, because hydrocarbon fuel is required not only for the propulsive power but also as a coolant with high cooling capacity due to its endothermic pyrolysis reaction at high temperature [6][7][8]. But, the tradition cracking process need high temperature and cause many environmental related problems.…”