Numerical Simulation of Hydrodynamics and Cracking Reactions in the Feed Mixing Zone of a Multiregime Gas–Solid Riser Reactor

Abstract

A CFD simulation was performed to evaluate the performance of a novel multiregime gas–solid fluidized riser reactor that was designed to maximize the propylene yield from the catalytic cracking process. Simulation results of the industrial-scale riser reactor show the coexistence of different regimes in the reactor. Also, both the outlet product compositions and the reaction rate vectors indicate that the cracking reactions mainly take place in the feed injection section. The product quality and distribution demonstrate the superiority of this novel process technology. The results of the CFD simulations are in good agreement with the test run results of a real industrial FCC reactor.

An integrated methodology for the modeling of Fluid Catalytic Cracking (FCC) riser reactor

“…Moreover, the ERN model can perform the steady-state simulation of FCC process in only several seconds on a single desktop personal computer, compared to multiple days/months on multiple processors for more detailed CFD-based simulations [4][5][6]13].…”

“…the 4th-category models in Table 1), highly detailed flow field structures can readily be obtained with CFD models. Such detail, however, requires quite a lot of computational efforts and time-consuming simulations, resulting in low accessibility in real-time dynamic simulation process [4][5][6]. On the other hand, the assumption of plug flow in riser reactors (e.g.…”

CFD investigation of hydrodynamics, heat transfer and cracking reactions in a large-scale fluidized catalytic cracking riser

“…An FCC riser is generally divided into four parts; the prelifting zone, the feedstock injection zone, the full reaction zone and the quenching zone. [1] FCC risers have been commercialized for over 70 years with many innovative technologies being implemented to satisfy evolving market demands and meet new challenges linked to the processing of an increasingly heavier crude oil. Some of these emerging FCC technologies such as atmospheric residue maximizing gas and gasoline (ARGG) process, maximizing iso-paraffin in cracked naphtha (MIP) process, [2] riser reaction termination technology to minimize over cracking, [3] mixing of deactivated catalysts with regenerated catalysts [4] to achieve low temperature contact with catalysts, two stage riser fluidized catalytic cracking for maximizing propylene (TSRFCC-TMP), [5,6] and flexible dualriser fluid catalytic cracking (FDFCC) [7] process to decrease gasoline olefin and increase propylene, have been widely adopted.…”

“…Recently, a noticeable increase in the global demand for propylene has shifted the focus of refineries towards FCC technologies that maximize production of propylene in order to achieve economic profits. Several recent studies [1,[8][9][10] have explored the design scheme, preparation of catalysts, and corresponding lumped kinetic models in FCC riser aimed at maximizing propylene. In the two stage riser catalytic pyrolysis for maximizing propylene yield (TMP) [6] technology, atmospheric residue and C 4 mixture gas are processed in A C C E P T E D M A N U S C R I P T 5 the first stage of the riser, whereas recycle oil and light gasoline are fed into the second stage.…”

Comparative study of gas–solids flow patterns inside novel multi-regime riser and conventional riser

“…To improve the hydrodynamics and intensify the interaction between gas-solids phases, various new riser structures have been designed, such as the riser with a diameter-enlarged section [12][13][14][15] or even coupled with draft tube generating internal solids circulation [16,17], circulating-turbulent fluidized bed (C-TFB) integrated with the advantages of both circulating and turbulent fluidized beds [18,19], and the tapered riser possessing high operating flexibility [20,21]. Due to simple application and unit upgrade, risers equipped with top/bottom-enlarged section have been extensively applied to FCC processes for different processing purposes.…”