Hydrocarbon Pyrolysis

A reactor for pyrolysing a hydrocarbon feed under predetermined pyrolysis conditions, the reactor comprising

• (a) an elongated tubular vessel having (i) an internal volume which includes first and second regions and (ii) opposed first and second openings in fluidic communication with the internal volume, the first and second openings being separated by a reactor length (LR), and
• (b) a channeled thermal mass located in the first region, wherein the first channeled thermal mass has a solid density (ρs)≤12 g/cm3, a heat capacity (Cp) ≤0.5 cal/g° C., and an open frontal area (OFA), and wherein
• (i) the first channeled thermal mass includes:
• (A) a first aperture, the first aperture being proximate to the first opening and in fluidic communication with the first opening,
• (B) at least one internal channel in fluidic communication with the first aperture, and
• (C) a second aperture, the second aperture being in fluidic communication with the first aperture via a flowpath L1 through the channel, L1 being ≥0.1*LR;
• and
• (ii) the OFA is determined from the formula:
• ([OFA-1]/OFA)=(tR*ρs*Cp*R*Tav*ΔTav)−1*(tP*X*ΔH*P), wherein,
• (A) R is the feed's Gas Constant and
• (B) the predetermined pyrolysis conditions include a residence time in the channel (tR)≤1 sec., a feed conversion (X)≥50%, an average total pressure in the channel (P)≥1 bar, an average bulk gas temperature in the channel (Tav)≤1500° C. at the start of the pyrolysis, a peak gas temperature (Tp) located in the channel, Tp>Tav, a pyrolysis step time tP in the range of from 0.001 sec. to 50 sec., and a change in average bulk gas temperature during the pyrolysis (ΔTav)≤100° C.