A Review of Modelling of the FCC Unit—Part II: The Regenerator

Abstract

Heavy petroleum industries, including the Fluid Catalytic Cracking (FCC) unit, are among some of the biggest contributors to global greenhouse gas (GHG) emissions. The FCC unit’s regenerator is where these emissions originate mostly, meaning the operation of FCC regenerators has come under scrutiny in recent years due to the global mitigation efforts against climate change, affecting both current operations and the future of the FCC unit. As a result, it is more important than ever to develop models that are accurate and reliable at predicting emissions of various greenhouse gases to keep up with new reporting guidelines that will help optimise the unit for increased coke conversion and lower operating costs. Part 1 of this paper was dedicated to reviewing the riser section of the FCC unit. Part 2 reviews traditional modelling methodologies used in modelling and simulating the FCC regenerator. Hydrodynamics and kinetics of the regenerator are discussed in terms of experimental data and modelling. Modelling of constitutive parts that are important to the FCC unit, such as gas–solid cyclones and catalyst transport lines, are also considered. This review then identifies areas where the current generation of models of the regenerator can be improved for the future. Parts 1 and 2 are such that a comprehensive review of the literature on modelling the FCC unit is presented, showing the guidance and framework followed in building models for the unit.

The Effects of Vaporisation Models on the FCC Riser Reactor

“…Therefore, further changes in temperature, coke concentration, and catalyst activity are minimal, as shown in the figures. The exit coke on catalyst concentration is predicted to be 0.55 wt%, which is within the normal range reported in the literature [5,52]. The exit temperature is ∼ 760 K, indicating a catalyst temperature drop of ∼ 200 K. Comparison of the catalyst temperature drop with previous work is not straight forward because of the disparities in the operating conditions, kinetic parameters, and physical properties of the phase mixtures.…”

“…Both the catalyst and the gas temperatures then decrease rapidly owing to the provision of latent and sensible heat to the liquid feed and the provision of heat energy to power the endothermic cracking reactions. The initial coke concentration on the regenerated catalyst was set to 0.1%, which is typical for FCC regenerator outlets [52]. Figure 5 shows that the coke content increases rapidly in the first 10 m of the riser during the progress of the cracking reactions, thus the activity of the catalyst decreases to less than 60% of its 'clean' activity in this region of the riser.…”

“…The deposition of coke will increase the density of the catalyst phase; however, it is assumed that this change is negligible, resulting in the constant density of the solid phase. This is a common assumption in the literature on the simulation of FCC riser reactions, and is justifiable given that the exit coke on the catalyst concentration from the riser is in the range of 0.5-1.5 wt% [52].…”

Generalized Net Model of Heavy Oil Products’ Manufacturing in Petroleum Refinery

“…It is treated in the petroleum refinery to extract additional amounts of light oil products and produce heavy oil products like fuel oil, marine fuels, and road pavement bitumen [7][8][9][10][11]. All processes involved in the technological chain of heavy oil treatment have been the subject of modeling and simulation with the aim to better understand the behavior of the heavy oil plants and determine the values of the operation variables providing the optimum performance from economical, energy saving, and environmental points of view [12][13][14][15][16][17][18][19][20]. Gaikwad et al [12] have simulated the operation of atmospheric residue vacuum distillation using Chemcad 5.1 software, with the aim to reduce the energy consumption.…”

“…Ye et al [14] have employed a molecular-level reaction kinetic model of delayed coking of vacuum residue based on the structure-oriented lumping method to predict the product yield and group composition in the actual delayed coking process. Selalame et al [15][16][17] have reviewed traditional modeling methodologies used in modeling and simulation of the fluid catalytic cracking (FCC) unit that converts vacuum gas oils and atmospheric residues into high-value light oil products. Wang et al [18] have modeled and simulated a real-life industrial residue hydrotreating process based on Aspen HYSYS/Refining process simulation software.…”