Gas–solid two‐phase flow in FCC riser

CFD simulation of gas–solid two-phase flow and mixing in a FCC riser with feedstock injection

“…Driven by the drag force of gas, the catalyst particles flow upward along the riser and then enter the cyclone where the catalysts are separated from gas-solid mixture and return the storage silo. The detailed description of the system can be found in Fan [49]. Owing to computational limitation, we only simulate the riser of the system, which is 0.186 m in diameter and 14 m in height.…”

“…In the feedstock injection zone, as shown in Figure 1(c), the grids are refined locally to improve the resolution of flow structures. In the experiment of Fan [49], the radial profiles of solids concentration and velocity…”

Downer‐to‐Riser Coupling Technique for Petroleum Refining

“…The core-annular flow structure in the riser leads to the non-uniform reaction conditions in the radial direction, with much more catalyst particles in the near-wall region, where the activities of the catalyst particles are evidently lower than the ones in the central region due to the more severe particle backmixing [33] and the higher temperature drop by endothermal catalytic cracking reactions [28].…”

Study of Feedstock Injection to Improve Catalyst Homogenization in the Riser of a FCC

“…In this respect, the works of Fan et al (2002) and Fan et al (2010) focused on the lift region and injection zone, and Gupta and Berruti (2000) and Harris et al (2003) investigated the effects of riser outlet geometry. Despite using cold-riser models, these experiments generated important data about the boundary and initial conditions, which were essential for numerical models.…”

“…About 5 m above this region is located the injection zone, where the feedstock (gas oil) is fed and the initial contact between the feedstock and the hot catalyst occurs, resulting in high gradients of temperature and concentration. According to Fan et al (2002), Gao et al (1999) and Theologos et al (1997), the initial contact is one of the most important aspects of the process, which affects the fluid dynamics and kinetics of the catalytic reaction. The feedstock is injected into the riser through nozzles, which aim to atomize the charge into small droplets and promote a perfect contact between the catalyst and the feedstock, thus minimizing regions of high catalyst concentration in order to avoid undesired reactions.…”