Fluid Catalytic Cracking Feed Research Articles

Roles of Catalysts and Feedstock in Optimizing the Performance of Heavy Fraction Conversion Processes: Fluid Catalytic Cracking and Ebullated Bed Vacuum Residue Hydrocracking

Petroleum refining has been, is still, and is expected to remain in the next decades the main source of energy required to drive transport for mankind. The demand for automotive and aviation fuels has urged refiners to search for ways to extract more light oil products per barrel of crude oil. The heavy oil conversion processes of ebullated bed vacuum residue hydrocracking (EBVRHC) and fluid catalytic cracking (FCC) can assist refiners in their aim to produce more transportation fuels and feeds for petrochemistry from a ton of petroleum. However, a good understanding of the roles of feed quality and catalyst characteristics is needed to optimize the performance of both heavy oil conversion processes. Three knowledge discovery database techniques—intercriteria and regression analyses, and artificial neural networks—were used to evaluate the performance of commercial FCC and EBVRHC in processing 19 different heavy oils. Seven diverse FCC catalysts were assessed using a cascade and parallel fresh catalyst addition system in an EBVRHC unit. It was found that the vacuum residue conversion in the EBVRHC depended on feed reactivity, which, calculated on the basis of pilot plant tests, varied by 16.4%; the content of vacuum residue (VR) in the mixed EBVRHC unit feed (each 10% fluctuation in VR content leads to an alteration in VR conversion of 1.6%); the reaction temperature (a 1 °C deviation in reaction temperature is associated with a 0.8% shift in VR conversion); and the liquid hourly space velocity (0.01 h-1 change of LHSV leads to 0.85% conversion alteration). The vacuum gas oil conversion in the FCC unit was determined to correlate with feed crackability, which, calculated on the basis of pilot plant tests, varied by 8.2%, and the catalyst ΔCoke (each 0.03% ΔCoke increase reduces FCC conversion by 1%), which was unveiled to depend on FCC feed density and equilibrium FCC micro-activity. The developed correlations can be used to optimize the performance of FCC and EBVRHC units by selecting the appropriate feed slate and catalyst.

Direct production of olefins from waste plastic using a pyrolysis and fluid catalytic cracking integrated process: Part 1. study on the production and analysis of waxy oil obtained using a new type of a fluidized bed reactor

The ultimate aim of this research is to produce ethylene and propylene directly from waste plastic. To achieve this, we designed a new cracker having a fluidized bed reactor (FBR) and a fluid catalytic cracking (FCC) unit. The FBR produces oil in vapor phase, and the FCC unit transforms the vapor into olefins. As a first step toward achieving the research goal, the current study conducts pyrolysis of low-density polyethylene using a new pyrolysis process having a FBR. By understanding characteristics of pyrolysis oils obtained in this study, it becomes possible to determine its suitability as FCC feed and its relationship with olefin productivity. The current investigation focused on the effects of vapor residence time, reaction temperature, and type of fluidizing medium on yield and composition of oil. The results showed that the waxy oil yield depended highly on reaction temperature, reaching a maximum of about 95 wt%. The sum of yields of n-alkenes and n-alkadienes, which are favorable for producing olefins when catalytically cracked in the FCC unit, reached 82 wt%. SIMDIS analysis, which determines the boiling point range distribution of oil, revealed strong effects of reaction temperature and residence time on the carbon numbers of the waxy oil.

CO2 capture and hydrogen generation from a solar-assisted and integrated fluid catalytic cracking process: Energy, exergy, and economic analysis

The fluid catalytic cracking (FCC) process transforms heavy wastes into lighter, more valuable (naphtha, light olefins and gases) products. However, the unit's byproducts contain a large quantity of CO2, which contributes to global warming. As a result, the purpose of this research was to increase the production of valuable products such as light olefins, naphtha, and hydrogen while reducing environmental impacts using the water gas shift reaction, with sensitivity analysis for three parameters (riser height, FCC feed temperature, and inlet naphtha mass flow). As a result of increasing the riser height, the output of light olefins (45%) and gases (32%) increased. Furthermore, the amount of hydrogen produced increases with a decrease in riser height (about 6%) and an increase in inlet naphtha mass flow (about 8%). Energy and exergy assessments were also carried out. It was determined that FCC had the lowest exergy destruction with a contribution of 23 MW when compared to its energy usage of 172 MW. The cooler, on the other hand, was one of the process's most energy-consuming (25%) and damaging (26%). As a result, this technique can lessen environmental effects by absorbing 125 tons of CO2 every hour and producing 3484 kg/h of hydrogen. Economic evaluations were also undertaken, and the results revealed that the cooler has the lowest exergoeconomic factor (1%) while the FCC unit contributes the most (95%). The fractionator column is also the most expensive device in the whole process.

Industrial Investigation of the Combined Action of Vacuum Residue Hydrocracking and Vacuum Gas Oil Catalytic Cracking While Processing Different Feeds and Operating under Distinct Conditions

Ebullated bed vacuum residue hydrocracking and fluid catalytic cracking (FCC) are among the most profitable processes in modern refining. Their optimal performance is vital for petroleum refining profitability. That is why a better understanding of their combined action and the interrelations between these two heavy oil conversion processes in a real-world refinery could provide valuable information for further performance optimization. Nine distinct petroleum crudes belonging to the extra light, light, and medium petroleum crude types were processed in the LUKOIL Neftohim Burgas refinery to study the combined performance of two processes: FCC of vacuum gas oil and ebullated bed vacuum residue H-Oil hydrocracking. The operating conditions along with the characterization data of the feeds and products of both processes were evaluated through the employment of intercriteria analysis to define the variables with statistically significant relationships. Maple 2023 Academic Edition mathematics software was used to develop models to predict the vacuum residue conversion level under different operating conditions. The plug flow reactor model with an activation energy of 215 kJ/mol and a reaction order of 1.59 was found to provide the highest accuracy of vacuum residue conversion, with an average absolute deviation of 2.2%. H-Oil yields were found to correlate with the vacuum residue conversion level and the content of FCC slurry oil (SLO), the recycling of partially blended fuel oil, a material boiling point below 360 °C, and the vacuum gas oil (VGO) in the H-Oil feed. FCC conversion was found to depend on the H-Oil VGO content in the FCC feed and the content of FCC SLO in the H-Oil feed.

Wood Derived Fast Pyrolysis Bio-liquids as Co-feed in a Fluid Catalytic Cracking Pilot Plant: Effect of Hydrotreatment on Process Performance and Gasoline Quality.

Co-feeding biogenic feeds in fluid catalytic cracking (FCC) units benefits from exploiting existing refinery assets to produce biogenic fuels. It is the most cost-effective way to comply with step-by-step increasing the target of renewable energy in road and rail transport of the European Union. Fast pyrolysis bio-liquids derived from wood offer a unique opportunity to reach those targets without having to address the typical food vs fuel debate. In the present work bio-liquids derived from pinewood in different stages of treatment were tested for their processability in a pilot scale fluid catalytic cracking plant at 550 °C. Specific focus is on the quality of the derived gasoline fractions. All samples were co-fed with vacuum gas oil, a typical FCC feed. Relevant parameters to qualify the produced gasoline as blending component were analyzed. As main results, none of the parameters examined significantly affect the quality of the—now partially biogenic—gasolines, demonstrating the potentiality of the co-FCC process as a possible near future pathway to ensure high biofuel contents in commercially available fuels.

Reaction network and molecular distribution of sulfides in gasoline and diesel of FCC process

In order to guide the accurate control of the sulfides in gasoline and diesel of Fluid Catalytic Cracking (FCC) process, a molecular-level model was established based on the Structure Oriented Lumping (SOL) method. According to the molecular composition characteristics of FCC feed oil, a molecular composition matrix containing 4,148 structural vectors was constructed with 24 structural increments. Using MATLAB software, the SOL reaction rules were compiled and a complex reaction network containing of about 110,000 reactions was established. According to the classification rules, the sulfides in gasoline and diesel represented by 32 and 136 structural vectors were divided into mercaptans, thioethers, monocyclic thiophenes, benzothiophenes and dibenzothiophenes, respectively. The conversion law of sulfides in gasoline and diesel was investigated by tracking their generation paths and reaction paths in the reaction network. The effects of the operation conditions on the sulfide content in gasoline and diesel were calculated quantitatively.

Renewable-carbon recovery in the co-processing of vacuum gas oil and bio-oil in the FCC process – Where does the renewable carbon go?

This study aims to quantify the renewable-carbon content in the products produced by co-processing vacuum gas oil with up to 20 wt% bio-oil in the fluid catalytic cracking (FCC) process. The renewable-carbon content of 40 product samples collected at a demonstration-scale FCC unit was quantified by 14C isotopic analysis.The renewable-carbon mass balance closure ranged between 90% and 110%. The biogenic-carbon content of the liquid effluent increased linearly as a function of the amount of bio-oil fed to the FCC. Most of the biogenic carbon was recovered as coke. Moreover, the renewable-carbon recovery in the liquid effluent remained at approximately 30 wt%, independent of the percentage of bio-oil fed to the FCC process. The FCC process is generally considered the largest single source of greenhouse gas (GHG) emissions in a petroleum refinery. These results will enable the life-cycle assessment from the co-processing of bio-oil in an FCC.The renewable carbon present in the coke deposited on the FCC catalyst, which is later burned during catalyst regeneration in the FCC, would contribute to GHG emission abatement. Additionally, the use of bio-oil as an FCC feed could contribute to reducing the carbon intensity of gasoline, diesel, and fuel oil.

A Review of Modelling of the FCC Unit–Part I: The Riser

Heavy petroleum industries, including the fluid catalytic cracking (FCC) unit, are useful for producing fuels but they are among some of the biggest contributors to global greenhouse gas (GHG) emissions. The recent global push for mitigation efforts against climate change has resulted in increased legislation that affects the operations and future of these industries. In terms of the FCC unit, on the riser side, more legislation is pushing towards them switching from petroleum-driven energy sources to more renewable sources such as solar and wind, which threatens the profitability of the unit. On the regenerator side, there is more legislation aimed at reducing emissions of GHGs from such units. As a result, it is more important than ever to develop models that are accurate and reliable, that will help optimise the unit for maximisation of profits under new regulations and changing trends, and that predict emissions of various GHGs to keep up with new reporting guidelines. This article, split over two parts, reviews traditional modelling methodologies used in modelling and simulation of the FCC unit. In Part I, hydrodynamics and kinetics of the riser are discussed in terms of experimental data and modelling approaches. A brief review of the FCC feed is undertaken in terms of characterisations and cracking reaction chemistry, and how these factors have affected modelling approaches. A brief overview of how vaporisation and catalyst deactivation are addressed in the FCC modelling literature is also undertaken. Modelling of constitutive parts that are important to the FCC riser unit such as gas-solid cyclones, disengaging and stripping vessels, is also considered. This review then identifies areas where current models for the riser can be improved for the future. In Part II, a similar review is presented for the FCC regenerator system.

Role of Catalyst in Optimizing Fluid Catalytic Cracking Performance During Cracking of H-Oil-Derived Gas Oils

Three H-Oil gas oils, heavy atmospheric gas oil (HAGO), light vacuum gas oil (LVGO), heavy vacuum gas oil (HVGO), and two their blends with hydrotreated straight run vacuum gas oils (HTSRVGOs) were cracked on two high unit cell size (UCS) lower porosity commercial catalysts and two low UCS higher porosity commercial catalysts. The cracking experiments were performed in an advanced cracking evaluation fluid catalytic cracking (FCC) laboratory unit at 527 °C, 30 s catalyst time on stream, and catalyst-to-oil (CTO) variation between 3.5 and 7.5 wt/wt The two high UCS lower porosity catalysts were more active and more coke selective. However, the difference between conversion of the more active high UCS lower porosity and low UCS higher porosity catalysts at 7.5 wt/wt CTO decreased in the order 10% (HAGO) > 9% (LVGO) > 6% (HVGO) > 4% (80% HTSRVGO/20% H-Oil VGO). Therefore, the catalyst performance is feedstock-dependent. The four studied catalysts along with a blend of one of them with 2% ZSM-5 were examined in a commercially revamped UOP FCC VSS unit. The lower UCS higher porosity catalysts exhibited operation at a higher CTO ratio achieving a similar conversion level with more active higher UCS lower porosity catalysts. However, the higher UCS lower porosity catalysts made 0.67% Δ coke that was higher than the maximum acceptable limit of 0.64% for this particular commercial FCC unit (FCCU), which required excluding the HVGO from the FCC feed blend. The catalyst system containing ZSM-5 increased the LPG yield but did not have an impact on gasoline octane. It was found that the predominant factor that controls refinery profitability related to the FCCU performance is the FCC slurry oil (bottoms) yield.

Virgin Heavy Gas Oil from Oil Sands Bitumen as FCC Feed

This study deals with a systematic investigation of the fluid catalytic cracking (FCC) performance of a bitumen-derived virgin heavy gas oil (HGO) in the presence of its counterpart from bitumen-derived synthetic crude oil (SCO). The objective is to determine the amelioration effect on yield and product slate by the addition of the premium SCO HGO. The 343–525 °C cut virgin bitumen HGO was obtained from distillation of a raw Athabasca oil sands bitumen. It was then blended with different amounts of the 343 °C+ fraction of commercial SCO. Four HGO blends were prepared containing 75, 64, 61, and 48 v% of SCO HGO. Each HGO blend, as well as 100% SCO HGO, were catalytically cracked at 500 and 520 °C using a bench-scale Advanced Cracking Evaluation (ACE) unit. The results show acceptable FCC performance of bitumen virgin HGO when an adequate amount of SCO HGO is added. However, the resulting liquid product may need some quality improvement before use. Several observations, including catalyst poisoning by feed nitrogen and the refractory nature of virgin HGO, are evident and help to explain some observed cracking phenomena.

Catalyst to oil mass ratio optimization on fluid catalytic cracking process in green gasoline production

Palm oil has potential as raw material for green gasoline as renewable energy source. One of the most important variables to support the achievement optimum operating condition in the Fluid Catalytic Cracking (FCC) process was the mass ratio of catalyst to oil (c/o). The FCC process simulation was carried out by using an Advance Cracking Evaluation (ACE) unit at mass ratio c/o (4.00, 5.00, 5.56, 6.00, 6.52) w/w ASTM D3907. The quality test of the FCC product were distribution of boiling point by using Refinery Gas Analyzer (RGA) Chromatography ASTM D2504 and using high temperature distillation simulating gas chromatography ASTM D7169, octane number by using Detailed Hydrocarbon Analysis (DHA) Chromatography ASTM D6730 and coke formation by using CO Analyzer ASTM D6316. The study shown that the most optimum c/o ratio in FCC process was at ratio 6.00 w/w with the amount of dry gas product 2.48 percent w/w, LPG 27.36 percent w/w, gasoline 41.81 percent w/w, LCO 11.54 percent w/w, HCO 0.00 percent w/w, bottom 3.71 w/w, and coke 12.99 percent w/w with octane number was 84.693. It can be concluded that FCC process of the palm oil mixture feed at this ratio has better quality than PT Pertamina’s FCC feed.

Co-processing of wood and wheat straw derived pyrolysis oils with FCC feed—Product distribution and effect of deoxygenation

The behavior of bio-oils when co-processed with conventional fossil feed in a fluid catalytic cracking (FCC) unit is suitably tested using a microactivity testing unit (MAT). In the present study, non-catalytic fast pyrolysis oils originating from wood and wheat straw were co-processed in a MAT at a 20/80 weight blend (bio-oil/FCC feed). In addition, bio-oil obtained from deoxygenating the straw derived vapors over a steamed HZSM-5/Al2O3 extrudate catalyst was tested. The bio-oils were characterized for elemental composition and moisture content to calculate energy recoveries, amounting to 35% and 30% for the non-catalytically obtained wood and straw oils, while it was 19% for the partly deoxygenated straw oil. Wood oil showed higher acidity (61 mg KOH/g) and molar O/C ratio (0.35) compared to straw oil (54 mg KOH/g and O/C = 0.24). The acidity and O/C ratio was reduced for the straw-derived bio-oil from catalytic vapor treatment (3 mg KOH/g, O/C = 0.08). At constant conversion (77.5%) at the MAT, the wood pyrolysis oil showed a product distribution quite similar to the reference oil while the wheat straw pyrolysis oil gave a 1.6% points higher coke yield and a 1.2% points lower liquid petroleum gas (LPG) yield. For the catalytically treated wheat straw pyrolysis oil, an even higher coke yield (2.6% points) and 1.9% points lower LPG yield resulted. The observations are attributed to the higher content of aromatics, phenolics, and nitrogen containing compounds of the catalytically upgraded straw fast pyrolysis oil.

Co-processing of hydrothermal liquefaction algal bio-oil and petroleum feedstock to fuel-like hydrocarbons via fluid catalytic cracking

In order to assess the utility of fluid catalytic cracking (FCC) for upgrading bio-oils derived from the hydrothermal liquefaction (HTL) of microalgae, 10 wt% HTL algae bio-oil was blended with heavy vacuum gas oil (HVGO) and co-processed in a Short Contact Time Microactivity unit. Compared to pure HVGO, addition of 10 wt% HTL algae bio-oil caused a modest decrease in conversion at all catalyst-to-oil ratios, with marginally increased catalyst coking being observed for the blended feed. The resulting liquid products contained a higher percentage of decant oil (DCO) and a lower percentage of gasoline than those obtained when HVGO alone was employed as feed, the amount of light cycle oil (LCO) being similar in both cases. Nearly complete heteroatom removal from the blended feed was observed, the extent of denitrogenation achieved being particularly noteworthy given that nitrogen-bearing compounds are much more abundant in algae-derived bio-oils than in HVGO. Overall, results indicated that while 10% bio-oil in HVGO would be economically unfavorable when compared to upgrading HVGO alone, it is nonetheless amenable to co-processing and may offer advantages over pyrolysis oils as an FCC feed. Finally, additional means to optimize the commercial application of this process are proposed based on techno-economic considerations.

Co‐processing bio‐oil in the refinery for drop‐in biofuels via fluid catalytic cracking

Pyrolysis oil from lignocellulosic biomass (bio‐oil) is a promising renewable energy carrier that can be utilized for the production of second‐generation drop‐in biofuels. Co‐processing bio‐oil with petroleum feeds in existing refinery processes, such as fluid catalytic cracking (FCC), has been proposed as a cost‐effective way of transitioning to the production of such biofuels without the need for significant capital‐intensive investments. Several routes are available for the production of bio‐oil, such as fast pyrolysis of biomass (raw bio‐oil), catalytic fast pyrolysis of biomass (catalytic pyrolysis oil, CPO), and fast pyrolysis of biomass followed by hydrogenation of the produced bio‐oil (hydrodeoxygenated oil, HDO). Research has shown that co‐processing raw bio‐oil is challenging but it can be carried out after adoption of appropriate reactor modifications in the commercial scale. A significant body of work has also focused on the co‐processing of HDO and CPO, and has demonstrated that these types of bio‐oil can be co‐processed with less operational issues. Co‐processing bio‐oil results in a liquid hydrocarbon product that contains only a small amount of oxygenates from bio‐oil. A noticeable increase in coke formation is also observed when bio‐oil is introduced in the FCC feed. However, this increase is lower than what would be expected from the conversion of the pure bio‐oil fraction. This has been attributed to the presence of the petroleum feed, which has a beneficial synergistic effect on the cracking of bio‐oil due to hydrogen donation reactions that inhibit coke formation and promote the conversion of the oxygenates to liquid hydrocarbons.This article is categorized under: Energy and Climate > Climate and Environment Bioenergy > Systems and Infrastructure Bioenergy > Economics and Policy

Nanoporous materials forge a path forward to enable sustainable growth: Technology advancements in fluid catalytic cracking

An overview is presented on the central role that zeolites and other nanoporous materials currently play in the Fluid Catalytic Cracking (FCC) process as well as how this role evolved over the course of the years since its inception. Today, utilization in FCC constitutes the vast majority of global zeolite catalyst consumption by volume. FCC is the main conversion process in a typical fuels refinery, and as the most critical ingredient of the catalyst, zeolites are responsible for producing majority of the gasoline used around the world as well as taking an important role in the production of other transportation fuels (e.g., diesel, jet fuel) and building blocks for the petrochemical industry (e.g., propylene, butylenes). Therefore, it can be stated that zeolite catalysts fuel our industrialized society and provide the building blocks for its advancement; consequently, zeolites have a direct impact on the future of the global economy and its sustainability. Strategies that involve zeolites and other nanoporous materials for improving performance of FCC operation and ensuring its environmental sustainability were reviewed. Zeolite modifications were examined with each leading to an improvement in zeolite stability under severe conditions in an FCC unit. The importance of diffusion pathways within an FCC catalyst particle, leading to higher accessibility of the active zeolite sites, were explored, and the importance of a well-designed catalyst architecture, allowing FCC feed, intermediates, and final products to diffuse freely in and out of the catalyst particle were discussed. The role of contaminant metals in FCC was investigated, and some mitigation strategies for the most common FCC contaminants, nickel and vanadium, were presented. The impact of contaminant iron was discussed alongside catalyst architecture, particularly surface porosity of the catalyst particle. Utilization of other nanoporous materials in FCC, especially as environmental additives, was summarized. Testing considerations were screened with an emphasis on matching laboratory deactivation to refinery FCC observations.

Fast pyrolysis oil from pinewood chips co-processing with vacuum gas oil in an FCC unit for second generation fuel production

Raw bio-oil produced from fast pyrolysis of pine woodchips was co-processed with standard Brazilian vacuum gasoil (VGO) and tested in a 200kg⋅h−1 fluid catalytic cracking (FCC) demonstration-scale unit using a commercial FCC equilibrium catalyst. Two different bio-oil/VGO weight ratios were used: 5/95 and 10/90.Co-processing of raw bio-oil in FCC was shown to be technically feasible. Bio-oil could be directly co-processed with a regular gasoil FCC feed up to 10wt%. The bio-oil and the conventional gasoil were cracked into valuable liquid products such as gasoline and diesel range products.Most of the oxygen present in the bio-oil was eliminated as water and carbon monoxide as these yields were always higher than that of carbon dioxide. Product quality analysis shows that trace oxygenates, primarily alkyl phenols, in FCC gasoline and diesel products are present with or without co-processing oxygenated intermediates. The oxygenate concentrations increase with co-processing, but have not resulted in increased concerns with quality of fuel properties.The presence of renewable carbon was confirmed in gasoline and diesel cuts through 14C isotopic analysis, showing that renewable carbon is not only being converted into coke, CO, and CO2, but also into valuable refining liquid products. Thus, gasoline and diesel could be produced from lignocellulosic raw materials through a conventional refining scheme, which uses the catalytic cracking process. The bio-oil renewable carbon conversion into liquid products (carbon efficiency) was approximately 30%, well above the efficiency found in literature for FCC bio-oil upgrading.

Water-washing to reduce metals in oils extracted from Nannochloropsis algae for potential FCC feedstock

Abstract Algae cultivation offers the potential to produce biofuels with much higher productivity than conventional soil-based crops. Organic oils can be extracted from algae using solvents such as alcohols and paraffins. A challenge is to define the most economical means to process these extracted oils into products such as chemical intermediates and liquid fuels. One approach is to add algal oils directly into the petroleum-based feeds to existing refinery processes such as fluid catalytic cracking (FCC) or hydroprocessing. Maximum acceptable levels were defined for contaminants such as sodium, potassium, calcium, phosphorus, and nitrogen in the feed to an FCC unit, based on refinery experience. Cracking runs in a laboratory unit confirmed the large decrease in conversion for high levels of sodium and potassium. For a laboratory sample of Nannochloropsis algae, the level of metals was far too high in the whole algae or in oils extracted from the algae using ethanol or n-heptane to allow their inclusion in FCC feedstock, even at a level of 2% algal product in the FCC feed. Washing the extracted oil with water removed only modest amounts of metals. It was found that washing the algae with water first, and then doing solvent extractions, resulted in oils with metals levels low enough for co-feeding to an FCC unit at a level of 2%. The oil yields by mass from the starting algae from this route were 21% for ethanol solvent, and 10% for heptane solvent. If an FCC unit were completely dedicated to bio-feeds without the necessity of co-processing petroleum feedstocks, the unit might operate with a different catalyst and different set of operating constraints, but that is beyond the scope of this study.

Comparison of vaporization models for feed droplet in fluid catalytic cracking risers

Vaporization of atomized feedstock is one of the critical processes in fluid catalytic cracking (FCC) risers; which is more often ignored in most of the FCC riser modelling studies. In this study, two different vaporization mechanisms of feedstock namely homogeneous mode and heterogeneous mode were studied. Different homogeneous models duly validated for various pure component droplets were applied to predict the vaporization time of the feed droplets typically expected in FCC feed vaporization zone. A new physical model for heterogeneous vaporization considering droplet–particle collision mechanics was also developed in the present study which compared well with the other existing heterogeneous modelling approaches. Comparison of the two vaporization modes indicates that under typical operating conditions of FCC riser, vaporization time of feed droplets predicted by heterogeneous mode is always lower than the homogeneous mode at least by an order of magnitude due to significant increase in heat transfer coefficient which accounts for droplet-particle contact. It is expected that actual vaporization time of feed droplets in an industrial FCC riser should lie in the range predicted by these two vaporization mechanisms which actually set the two limiting modes of vaporization. Obtained results predicted by the models could be used to aid design of the FCC feed vaporization zone.

Co-processing raw bio-oil and gasoil in an FCC Unit

Bio-oil is a complex blend of oxygenated compounds, such as acetic acid, hydroxyacetone and phenols, and is produced from the fast pyrolysis of raw biomass. A raw bio-oil produced from pine woodchips was co-processed with standard gasoil and tested in a 150kg/h fluid catalytic cracking (FCC) demonstration-scale unit. The bio-oil was cracked into valuable products, such as gasoline and LCO, with similar product yields obtained from the base FCC feed when up to 10% bio-oil was used. However, some deterioration was observed when 20% bio-oil was added. 14C isotopic analyses were performed to determine the renewable carbon content in the FCC liquid products. When 20% bio-oil was co-processed, the renewable carbon content in the gasoline cuts varied between 3% and 5%. For 10% bio-oil in the feed, 2% renewable carbon was obtained in the total liquid product. Large amounts of phenolic compounds were detected in the naphtha produced by the FCC. The FCC carbon efficiency, which is defined as the amount of carbon in bio-oil converted to carbon in the total liquid products, was approximately 30%, well above the values found in the literature for FCC bio-oil upgrading (15%–20%) when using laboratory scale units.

Estimation of FCC feed composition from routinely measured lab properties through ANN model

Realistic kinetic modeling of fluid catalytic cracking (FCC) units requires detailed composition of the feed stream in terms of paraffins, naphthenes and aromatics(PNA) which cannot be analyzed in a field laboratory. This paper presents an artificial neural network (ANN) model to predict detailed composition of FCC feed using routinely measured properties such as density, ASTM distillation temperatures, Conradson carbon residue (CCR) content, sulfur and total nitrogen as inputs to the model. Several feedforward-error back propagation networks with different number of neurons in hidden layers were studied using Levenberg–Marquardt (LM) training algorithm. Among different network architectures investigated, the ANN model with 8 inputs, namely density and ASTM distillation temperatures except IBP, FBP and only one neuron in the output layer to predict paraffin, naphthene and aromatic contents individually showed the best agreement with the experimental results within permissible limit. These compositions when used with a 10-lump kinetic model of FCC unit, successfully simulated plant performance for several different feeds.