High-Severity FCC Technologies as Alternative to Face the Hostile Scenario Imposed to Fossil Fuels

Introduction and Context

The current scenario present great challenges to the crude oil refining industry, prices volatility of raw material, pressure from society to reduce environmental impacts and refining margins increasingly lower. The newest threat to refiners is the reduction of the consumer market, in the last years became common, news about countries that intend to reduce or ban the production of vehicles powered by fossil fuels in the middle term, mainly in the European market. Despite the recent forecasts, the transportation fuels demand is still the main revenues driver to the downstream industry, as presented in Figure 1, based on data from Wood Mackenzie Company.

Figure 1 – Global Oil Demand by Derivative (Wood Mackenzie, 2020)

According to Figure 1, is expected a growing demand by petrochemicals while the transportation fuels tend to present falling consumption. Still according to Wood Mackenzie data, presented in Figure 2, due to the higher added value, the most integrated refiners tend to achieve higher refining margins than the conventional refiners which keep the operations focused on transportation fuels.

Figure 2 – Refining Margins to Integrated and Non-Integrated Refining Hardware (Wood Mackenzie, 2020)

NCM = Net Cash Margins

The improvement in fuel efficiency, growing market of electric vehicles tends to decline the participation of transportation fuels in the global crude oil demand. New technologies like additive manufacturing (3D printing) have the potential to produce great impact to the transportation demands, leading to even more impact over the transportation fuels demand. Furthermore, the higher availability of lighter crude oils favors the oversupply of lighter derivatives that facilitate the production of petrochemicals against transportation fuels as well as the higher added value of petrochemicals in comparison with fuels.

As aforementioned, face the current trend of reduction in transportation fuels demand at the global level, the capacity of maximum adding value to crude oil can be a competitive differential to refiners. Due to the high capital investment needed for the implementation that allows the conventional refinery to achieve the maximization of chemicals, capital efficiency becomes also an extremely important factor in the current competitive scenario as well as the operational flexibility related to the processed crude oil slate. Just the olefins market will rise a total value of US$ 322 billion dollars in 2026 with a growing rate of 4,0 % in 2022 to 2027 period according to recent forecasts.

Considering exclusively the propylene market, the forecasts are even more encouraging for investments in on purpose propylene production routes. Figure 3 presents the projection to propylene market size for the next years.

Figure 3 – Evolution of Propylene Market Size for the next years (Precedence Research, 2024)

According to Figure 3, the propylene market can reach values higher than 162 billion USA dollars in 2034 with an annual rate of 3,76 % with Asia being the bigger market as expected.

Considering the ethylene market, the scenario is even more attractive once is expected an annual growth rate of 5,72 % between 2024 and 2033 and the total size of the ethylene market can reach USD 241 billion in 2033 as presented in Figure 4. Again, the Asian continent is responsible of the major part of this growth.

Figure 4 – Evolution of Ethylene Market Size for the next years (Precedence Research, 2024)

Due to his similarities, better integration between refining and petrochemical production processes appears as an attractive alternative to maximize the yield of petrochemicals. Although the advantages, it’s important to consider that the integration between refining and petrochemical assets increase the complexity, requires capital spending, and affect the interdependency of refineries and petrochemical plants, these facts need to be deeply studied and analyzed case by case.

In this business environment, flexible refining technologies like Fluid Catalytic Cracking (FCC) can ensure high competitiveness to refiners once are capable to produce high quality intermediates both to petrochemicals and transportation fuels, in markets with great demand by petrochemicals, the petrochemical FCC technologies can be an attractive option, despite the high capital spending.

Synergies between Refining and Petrochemical Assets – The Concept of Petrochemical Integration

The focus of the closer integration between refining and petrochemical industries is to promote and seize the synergies existing opportunities between both downstream sectors to generate value to the whole crude oil production chain. Table 1 presents the main characteristics of the refining and petrochemical industry and the synergies potential.

As aforementioned, the petrochemical industry has been growing at considerably higher rates when compared with the transportation fuels market in the last years, additionally, represent a noblest destiny and less environmental aggressive to crude oil derivatives. The technological bases of the refining and petrochemical industries are similar which lead to possibilities of synergies capable to reduce operational costs and add value to derivatives produced in the refineries.

Figure 5 presents a block diagram that shows some integration possibilities between refining processes and the petrochemical industry.

Figure 5 – Synergies between Refining and Petrochemical Processes

Process streams considered with low added value to refiners like fuel gas (C2) are attractive raw materials to the petrochemical industry, as well as streams considered residual to petrochemical industries (butanes, pyrolysis gasoline, and heavy aromatics) can be applied to refiners to produce high quality transportation fuels, this can help the refining industry meet the environmental and quality regulations to derivatives.

The integration potential and the synergy among the processes rely on the refining scheme adopted by the refinery and the consumer market, process units as Fluid Catalytic Cracking (FCC) and Catalytic Reforming can be optimized to produce petrochemical intermediates to the detriment of streams that will be incorporated to fuels pool. In the case of FCC, installation of units dedicated to produce petrochemical intermediates, called petrochemical FCC, aims to reduce to the minimum the generation of streams to produce transportation fuels, however, the capital investment is high once the severity of the process requires the use of material with noblest metallurgical characteristics.

The IHS Markit Company proposed a classification of the petrochemical integration grades, as presented in Figure 6.

Figure 6 – Petrochemical Integration Levels (IHS Markit, 2018)

According to the classification proposed, the crude to chemicals refineries is considered the maximum level of petrochemical integration, where the processed crude is essentially converted into petrochemical intermediates like BTX (Benzene, Toluene, and Xylenes), and Light Olefins (Ethylene, Propylene, C4s).

Fluid Catalytic Cracking Technologies – The Conventional Process x Petrochemical Units

Fluid Catalytic Cracking (FCC) is one of the main processes which give higher operational flexibility and profitability to refiners. The catalytic cracking process was widely studied over last decades and became the principal and most employed process dedicated to converting heavy oil fractions in higher economic value streams.

The installation of catalytic cracking units allows the refiners to process heavier crude oils and consequently cheaper, raising the refining margin, mainly in higher crude oil prices scenario or in geopolitics crises that can become difficult the access to light oils.  The typical Catalytic Cracking Unit feed stream is gas oils from vacuum distillation process. However, some variations are found in some refineries, like sending heavy coke naphtha, coke gas oils and deasphalted oils from deasphalting units to processing in the FCC unit.

The catalyst normally employed in fluid catalytic cracking units is a solid constituted by small particles of alumina (Al2O3) and silica (SiO2) (zeolite). By the catalyst characteristics and the operational conditions in the catalytic cracking process (temperature higher than 500 oC), the process is inefficient to cracking aromatic compounds, therefore, how much more paraffinic is the feed stream, higher is the unit conversion. Figure 7 presents a process scheme for a typical Fluid Catalytic Cracking Unit (FCCU).

In a conventional scheme, the catalyst regeneration process consists in the carbon partial burning deposited over the catalyst, according to chemical reaction below:

C + ½ O2 → CO

The carbon monoxide is burned in a boiler capable of generating high pressure steam that supplies others process units in the refinery.

Figure 7 – Schematic Process Flow for a Typical Fluid Catalytic Cracking Process Unit (FCCU)

The principal operational variables in a fluid catalytic cracking unit are reaction temperature, normally considered the temperature in the top of the reactor (called riser), feed stream temperature, feed stream quality (mainly carbon residue), feed stream flow rate and catalyst quality. Feedstock quality is especially relevant, but this variable is a function of the crude oil processed by the refinery, so is difficultly can be changed, but for example, aromatic feedstock’s with high metals content are refractory to cracking and conducting to a quick catalyst deactivation.

An important variation of the fluid catalytic cracking technology is the residue fluid catalytic cracking unit (RFCC). In this case, the feedstock to the process is basically residue from atmospheric distillation column, due to the high carbon residue and contaminants (metals, sulfur, nitrogen, etc.) are necessary some adaptations in the unit like catalyst with higher resistance to metals and nitrogen and catalyst coolers furthermore, it’s necessary apply materials with most noble metallurgy due the higher temperatures reached in the catalyst regeneration step (due the higher coke quantity deposited on the catalyst), that raises significantly the capital investment to the unit installation. Nitrogen is a strong contaminant to the FCC catalyst because they neutralize the acid sites of the catalyst which are responsible for the cracking reactions.

When the residue has high contaminants content, is common the feed stream treatment in hydrotreating units to reduce the metals and heteroatoms concentration to protect the FCC catalyst.

Typically, the average yield in fluid catalytic cracking units is 55% in volume in cracked naphtha and 30 % in LPG.

The decanted oil stream contains the heavier products and have high aromatic content, is common that this product is contaminated with catalyst fines and normally this stream is directed to use like fuel oil diluent, but in some refineries, this stream can be used to produce black carbon.

Light Cycle Oil (LCO) has a distillation range close to diesel and normally this stream is directed to treatment in severe hydrotreating units (due to the high aromaticity), after this treatment the LCO is sent to the refinery diesel pool.

Heavy cracked naphtha is normally directed to refinery gasoline pool, however, in scenarios where the objective is to raise the production of middle distillates, this stream can be sent to hydrotreating units for further diesel production.

The overhead products from main fractionator are still in gaseous phase and are sent to the gas separation section.  The fuel gas is sent to the refinery fuel gas ring, after treatment to remove H2S, where will be burned in fired heaters while the LPG is directed to treatment (MEROX) and further commercialization.   The LPG produced by FCC unit have a high content of light olefins (mainly Propylene) so, in some refineries, the LPG stream is processed in a Propylene separation unit to recovery the propylene that has higher added value than LPG.

Cracked naphtha is usually sent to refinery gasoline pool which is formed by naphtha produced by other process units like straight run naphtha, naphtha from the catalytic reforming unit, etc. Due to the production process (deep conversion of residues), the cracked naphtha has high sulfur content and to attend the currently environmental legislation this stream needs to be processed to reducing the contaminants content, mainly sulfur.

The cracked naphtha sulfur removing represents a great technology challenge because is necessary to remove the sulfur components without molecules saturation that gives high octane number for gasoline (mainly olefins).

Over the last decades some technology licensers had developed new processes aiming to reduce the sulfur content in the cracked naphtha with minimum octane number loss, some of the main technologies dedicated for this purpose are technology PRIME G+ ™ from Axens, the processes OCTAGAIN ™ and SCANfining ™ from Exxon Mobil, the process S-Zorb™ from ConocoPhillips and ISAL™ technology from UOP.

Usually, catalytic cracking units are optimized to aiming the production of fuels (mainly gasoline), however, some process units are optimized to maximize the light olefins production (propylene and ethylene). Process units dedicated for this purpose have his project and operational conditions significantly changed once the process severity is strongly raised in this case.

The reaction temperature reaches 600 oC and higher catalyst circulation rate raises the gases production, which requires a scaling up of gas separation section.

In several cases, due the higher heat necessity of the unit is advantageous to operate the regenerator with the total combustion of the coke deposited on the catalyst, this arrangement significantly changes the thermal balance of the refinery once it’s no longer possible to resort the steam produced by the CO boiler.

Over last decades, the fluid catalytic cracking technology was intensively studied aiming mainly the development of units capable of producing light olefins (Deep Catalytic Cracking) and to process heavier feedstocks. The main licensers for fluid catalytic cracking technology nowadays are the companies KBR, UOP, STONE & WEBSTER, AXENS, and Lummus.

Improving the Yield of Petrochemicals in the Refining Hardware – Some Commercial Petrochemical FCC Technologies

As quoted earlier, in markets with high demand by petrochemicals, the petrochemical FCC can be an attractive alternative to refiners aiming to ensure higher added value to bottom barrel streams. An example of FCC technology developed to maximize the production of petrochemical intermediates is the PetroFCC™ process by UOP Company, this process combines a petrochemical FCC and separation processes optimized to produce raw materials to the petrochemical process plants, as presented in Figure 8. Other available technologies are the HS-FCC™ process commercialized by Axens Company, and INDMAX™ process licensed by Lummus Company. The basic process flow diagram for HS-FCC™ technology is presented in Figure 9.

Figure 8 – PetroFCC™ Process Technology by UOP Company.

It’s important to considering that both technologies presented in Figures 8 and 9 are based on Petrochemical FCC units that presents especial design due to the most severe operating conditions.

Figure 9 – HS-FCC™ Process Technology by Axens Company.

To petrochemical FCC units, the reaction temperature reaches 600 oC and higher catalyst circulation rate raises the gases production, which requires a scaling up of gas separation section.  The higher thermal demand makes advantageous operates the catalyst regenerator in total combustion mode leading to the necessity of installation a catalyst cooler system.

Figure 10 presents the results of a comparative study, carried out by Technip Company, showing the yields obtained by conventional FCC units, optimized to olefins (FCC to olefins), and the HS-FCC™ designed to maximize the production of petrochemical intermediates.

Figure 10 – Comparative Study between Conventional FCCs and Petrochemical FCC (HS-FCC™)

It’s observed a higher reaction temperature (TRX) and a cat/oil ratio five times higher when are compared the conventional process units and the petrochemical FCC (HS-FCC™), leading to a growth of the light olefins yield (Ethylene + Propylene + C4=’s) from 14 % to 40%.

The installation of petrochemical catalytic cracking units requires a deep economic study taking into account the high capital investment and higher operational costs, however, some forecasts indicate growth of 4,0 % per year to the market of petrochemical intermediates until 2025. In this scenario can be attractive the capital investment aiming to raise the market share in the petrochemical sector, allowing then a favorable competitive positioning to the refiner, through the maximization of petrochemical intermediates. Figure 11 presents a block diagram showing a case study demonstrating how the petrochemical FCC unit, in this case the INDMAX™ technology by Lummus Company, can maximize the yield of petrochemicals in the refining hardware. Another FCC technology dedicated to convert residue to olefins is the R2P™ process, developed by Axens Company.

Figure 11 – Olefins Maximization in the Refining Hardware with INDMAX™ FCC Technology by Lummus (SANIN, A.K., 2017)

In refining hardware with conventional FCC units, further than the higher temperature and catalyst circulation rates, it’s possible to apply the addition of catalysts additives like the zeolitic material ZSM-5 that can raise the olefins yield close to 9,0% in some cases when compared with the original catalyst. This alternative raises the operational costs, however, as aforementioned can be economically attractive considering the petrochemical market forecasts.  Figure 12 presents some optimization strategies to improve the petrochemical yield in conventional FCC units.

Figure 12 - Optimization of Process Variables in FCC Units to Improve the Yield of Petrochemicals Intermediates

The use of FCC catalyst additives such as ZSM-5 can increase unit propylene production by up to 8.0%.

Installation of catalyst cooler system raises the process unit profitability through the total conversion enhancement and selectivity to noblest products as propylene and naphtha against gases and coke production. The catalyst cooler necessary when the unit is designed to operate under total combustion mode due to the higher heat release rate as presented below.

C + ½ O2 → CO (Partial Combustion)  ΔH = - 27 kcal/mol

C + O2 → CO2 (Total Combustion)       ΔH = - 94 kcal/mol

In this case, the temperature of the regeneration vessel can reach values close to 760 oC, leading to higher risks of catalyst damage which is minimized through catalyst cooler installation. The option by the total combustion mode needs to consider the refinery thermal balance, once, in this case, will not the possibility to produce steam in the CO boiler, furthermore, the higher temperature in the regenerator requires materials with noblest metallurgy, this significantly raises the installation costs of these units which can be prohibitive to some refiners with restricted capital access.

Among another petrochemical FCC technologies, it’s possible to quote the Maxofin™ and K-COT™ processes developed by KBR Company and the SCC™ technology developed by Lummus Company. Figure 13 presents a basic process arrangement for the K-COT™ technology developed by KBR Company.

Figure 13 – Process Concept for the K-COT™ FCC Technology Developed by KBR Company (SINGH, 2018)

Due to the higher production of light olefins, mainly ethylene, another important difference between conventional and petrochemical FCC units is related to the gas recovery section, while in conventional FCC is applied absorber columns as presented in Figure 6, in petrochemical units is applied cryogenic processes though refrigeration cycles in similar conditions which are applied in steam cracking units, as presented in Figure 14 for the ACO™ technology developed by KBR Company.

Figure 14 – Olefins Recovery Section of ACO™ Technology by KBR Company (TALLMAN et. al., 2010)

The cryogenic processes applied to olefins recovery raises, even more, the capital requirement to petrochemical FCC units when compared with conventional FCCs, despite this, the growing market for petrochemicals and falling demand for transportation fuels, tends to compensate the higher investment.

The FCC Catalyst – Making the Miracle Possible

A key factor in the FCC operation is the catalyst applied in the process. The catalyst normally employed in fluid catalytic cracking units is a solid constituted by small particles of alumina (Al2O3) and silica (SiO2) (zeolite). By the catalyst characteristics and the operational conditions in the catalytic cracking process (temperature higher than 500 oC), the process is inefficient to cracking aromatic compounds, therefore, how much more paraffinic is the feed stream, higher is the unit conversion.

The active phase in the FCC catalyst is composed by the zeolite that is responsible by the catalytic activity and selectivity of the catalyst and by the alumina that is responsible by the cracking of heavier molecules allowing these molecules to reach the access to the zeolitic phase. The other components of the FCC catalysts are the inert (kaolim) and synthetic matrixes that are responsible to the mechanical resistance, hardness, and act as binder agent between the active phases and the matrix.

According to the process conditions, can be added some compounds to the catalyst with specific purpose. In refineries that processing feed streams with high amount of nickel it’s common to add antimony as that act as passivator agent, another deleterious metal is the vanadium, in this case is applied some trap agent to minimize his effects. The Figure 15 presents an arrangement of a typical design of FCC catalyst.

Figure 15 – Typical Design of FCC Catalyst (Grace Company, 2015)

As aforementioned, the processing of heavier crude oils leads to a more challenging feedstocks to FCC units due to the higher concentration of residual carbon and mainly contaminants as Nickel and Vanadium. The nickel acts as dehydrogenation agent leading to the coke deposition over the catalyst and raises the hydrogen production, normally the refiners used to process heavier feeds apply metals passivators as boron to keep under control the deleterious effect of metals, the most common form to control the nickel effects is to inject Antimony in the FCC feed. Figure 16 present the action mechanism of Nickel in the FCC reactions.

Figure 16 – Nickel Effects on the FCC Catalyst (SALGADO, 2018)

The vanadium effect over the FCC catalyst involves the degradation of the zeolite matrix leading to the reduction in the catalytic activity and his action is keep under control through vanadium traps. In the last years some catalyst developers are focusing his research to study the effects of iron in the FCC catalyst, the high concentration of iron is a characteristic of the shale oils produced in the North America and the availability of these crudes raises significantly in the last years, especially after 2015, when the United States starts to export his internal production. The iron is not catalytically active, but this compound can accumulate over the catalyst surface reducing the porosity reducing the activity and leading to dehydrogenation reactions as well as carbon monoxide (CO) promoter, furthermore the high concentration of Iron can raise the SOx emissions in the catalyst regenerator.

Another dangerous contaminant of FCC catalyst is the sodium, this compound promotes an irreversible deactivation of the catalyst through the chemical degradation of the zeolitic matrix. By this reason, an adequate control of the crude oil desalting process is fundamental to control the sodium content in the FCC feeds, preserving the catalyst lifecycle. Nowadays, some refiners are injected caustic soda in the crude to improve the desalting characteristics, and a stricter control is required in these cases. A less common contaminant founded in some crude oils is the copper, his effect is the promotion of dehydrogenation reactions, raising the yield of hydrogen and coke. The copper is present in some NOx reducing agents.

Aiming to improve the catalytic activity, some developers apply rare earth compounds to the FCC catalyst as Lanthanum and Cerium. These compounds raises significantly the activity and selectivity of the final catalyst, but his high cost made the refiners avoid his application, furthermore, the presence of rare earth in the catalyst improve yield of gasoline and reduces the light olefins production in FCC units, in the current scenario this is exactly the inverse that the refiners are looking for.

The trend of reduction in transportation fuels demand is making refiners to optimize his FCC units to maximize petrochemical intermediates against transportation fuels. To achieve this goal, normally the refiners are applying most severe conditions as higher catalyst/oil ratios, higher reaction temperature (TRX), and the use of ZSM-5 as additive to the catalyst.

The presence of ZSM-5 in the catalyst is capable to improve the yield of light olefins in the FCC unit by up to 8,0 %. One of the most important roles of the refineries optimization teams is to analyze the FCC equilibrium catalysts to find the improvement alternatives based on the contaminants content and the reached conversion of the unit as well as the degradation observed on the equilibrium catalysts. The volumetric conversion of an FCC unit is defined as Equation (1).

(1) Volumetric Conversion (%) = [Feed – (LCO + Decanted Oil)]/ Feed x 100

The fraction LCO and Decanted Oil (DO) is considered non converted fractions.

The main FCC catalyst developers present in the market nowadays are, BASF Catalysts Company, Albermarle, and W. R. Grace Company.

Propylene Recovery Section

The growing demand by petrochemicals lead some refiners to install propylene recovery units aiming to allow the maximization of light olefins yield in his refining hardware. Among the light olefins, the propylene is one of the most relevant petrochemical intermediate due to the high demand and added value.

The propylene can be applied as intermediate to the production some fundamental products, for example:

·       Acrylonitrile;

·       Propylene Oxide;

·       Cumene;

·       Acrylic Acid;

·       Polypropylene;

Propylene can be produced through conventional processes like Steam Cracking and Fluid Catalytic Cracking (FCC) or through directed processes like metathesis of ethylene and butane, propane dehydrogenation, olefins cracking, Methanol to Olefins processes (MTO), among others. Currently the major part of the propylene market is supplied by steam cracking units, but close to 28 % of the global propylene demand is from the separation of LPG produced in Fluid Catalytic Cracking Units (FCC).

Normally, the LPG produced in FCC units contain close to 30 % of propylene and the added value of the propylene is close to 2,5 times of the LPG. According to the local market, the installation of propylene separation units presents an attractive return over investment. Despite the advantage, a side effect of the propylene separation from LPG is that the fuel stays heavier leading to specifications issues, mainly in colder regions, in these cases alternatives are to segregate the butanes and send this stream to gasoline pool, add propane to the LPG or add LPG from natural gas. It’s important take into account that some of these alternatives reduce the LPG offer, which can be a severe restriction according to the market demand.

A great challenge in the propylene production process is the propane and propylene separation step. The separation is generally hard by simple distillation because the relative volatility between propylene and propane is close of 1.1. This fact generally conducts to distillation columns with many equilibrium stages and high internal reflux flow rates.

There are two technologies normally employed in propylene-propane separation towers that are known as Heat-Pump and High Pressure configurations.

The high pressure technology applies a traditional separation process that uses a condenser with cooling water to promotes the condensation of top products, in this case, it’s necessary to apply sufficient pressure to promote the condensation of products in the ambient temperature. Furthermore, the reboiler uses steam or another available hot source. The adoption of high pressure separation route requires a great availability of low pressure steam in the refining hardware, in some cases this can be a restrictive characteristic and the heat pump configuration is more attractive, despite the higher capital requirements.

The application of heat pump technology allows decrease the operating pressure by close of 20 bar to 10 bar, this fact increase the relative volatility propylene-propane, making the separation process easier and, consequently, reducing the number of equilibrium stages and internal reflux flow rate required for the separation.

Normally, when the separation process by distillation is hard (with relative volatilities lower than 1.5) the uses of heat pump technology show more attractive.

Furthermore, some variables need to be considerate during the choice of the best technology for the propylene separation process like availability of utilities, temperature gap in the column and installation cost.

Normally, the propylene is produced in the refineries with to specifications. The polymer grade that is most common and have higher added value with a purity of 99,5 % (minimum) this grade is directed to polypropylene market. The chemical grade where the purity varies between 90 to 95% is normally directed to other uses. A complete process flow diagram for a typical propylene separation unit applying heat pump configuration is presented in Figure 17.

Figure 17 – Typical Process Flow Diagram for an FCC Propylene Separation Unit Applying Heat Pump Configuration

The LPG from FCC unit is pumped to a depropanizer column where the light fraction (essentially a mixture of propane and propylene) is recovered in the top of the column and sent to a deethanizer column while the bottom (butanes) is pumped to LPG or gasoline pool, according to the refining configuration. The top stream of the deethanizer column (lighter fraction) is sent back to FCC where is incorporated to refinery fuel gas pool, or in some cases can be directed to petrochemical plants to recover the light olefins (mainly ethylene) present in the stream while the bottom of the deethanizer column is pumped to the C3 splitter column, where the separation of propane x propylene is carried out. The propane recovered in the bottom of the C3 splitter is sent to LPG pool where the propylene is sent to propylene storage park. The feed stream passes through a caustic wash treating aiming to remove some contaminants that can lead to deleterious effect to petrochemical processes, an example is the carbonyl sulfide (COS) that can be produced in the FCC (through the reaction between CO and S in the Riser).

Integrated Refining Schemes – Closer Integration with Petrochemical Assets

Historically, the refining industry growth was sustained and focused by transportation fuels, this can explain the profile of the traditional refining schemes showed above. Nowadays, the downstream industry is facing with a trend of reduction in transportation fuels demand, followed by a growing demand by petrochemicals, this fact is the main driving force to promote the change of focus in downstream industry.

The growing market of petrochemicals have been led some refiners to look for a closer integration between refining and petrochemicals assets aiming to reach more adherence with the market demand, improve revenues, and reduce operation costs. To reach this goal, the refiners are implementing most integrated refining schemes as presented in Figure 18.

Figure 18 – Example of an Integrated Refining Focusing on Petrochemicals Scheme by UOP Company

As presented in Figure 18, the integrated refining scheme rely on flexible refining technologies as catalytic reforming and fluid catalytic cracking (FCC) that are capable to reach the production of high quality petrochemicals and transportation fuels, according to the market demand. Another significant characteristic of the integrated refining schemes is the strongly synergy between deep conversion technologies like hydrogracking and fluid catalytic cracking units and processing units capable to produce high added value petrochemicals like steam cracking and catalytic reforming units.

A more integrated refining configuration allows the maximization of petrochemicals, raising the refining margins and ensures higher value addition to the processed crude oils. Another fundamental competitive advantage is the operational flexibility reached through the integrated refining configurations, allowing the processing of discounted and cheaper crude oils, raising even more the refining margins.

The Role of Petrochemical FCC Technologies in the Crude Oil to Chemicals Strategy

Due to the increasing market and higher added value as well as the trend of reduction in transportation fuels demand, some refiners and technology developers has dedicated his efforts to develop crude to chemicals refining assets. One of the big players that have been invested in this alternative is the Saudi Aramco Company, the concept is based on the direct conversion of crude oil to petrochemical intermediates as presented in Figure 19.

Figure 19 – Saudi Aramco Crude Oil to Chemicals Concept (IHS Markit, 2017)

The process presented in Figure 18 is based on the quality of the crude oil and deep conversion technologies like High Severity or petrochemical FCC units and deep hydrocracking technologies. The processed crude oil is light with low residual carbon that is a common characteristic in the Middle East crude oils, the processing scheme involves deep catalytic conversion process aiming to reach maximum conversion to light olefins. In this refining configuration, the petrochemical FCC units have a key role to ensure high added value to the processed crude oil.

Figure 20 present a comparison between the petrochemicals yields of traditional refineries, a benchmark integrated refinery and Hengli crude to chemicals complex, according to data from IHS markit.

Figure 20 – Petrochemicals Yield Comparison (IHS Markit, 2018)

Analyzing Figure 20 it’s possible to note the higher added value reached in crude to chemicals refineries when compared even with highly integrated refineries.

As aforementioned, face the current trend of reduction in transportation fuels demand at the global level, the capacity of maximum adding value to crude oil can be a competitive differential to refiners. Due to the high capital investment needed for the implementation that allows the conventional refinery to achieve the maximization of chemicals, capital efficiency becomes also an extremely important factor in the current competitive scenario as well as the operational flexibility related to the processed crude oil slate.

As described above, the fluid catalytic cracking units can ensure operational flexibility and higher refining margins for the downstream players under the challengeful scenario imposed to the fossil fuels and is expected growing investments in FCC installations for the next years. Based on data from GlobalData Company, the global installed fluid catalytic cracking capacity will raise from 14,4 million barrels per day (MMbpd) in 2022 to 15,8 MMbpd in 2026, a growth of 9,3 % in four years. Figure 21 presents an overview of the growth of FCC installed capacity for the next years.

Figure 21 – Growth of Global FCC Installed Capacity 2022 to 2026 (GlobalData Company, 2022)

As expected, the growth of FCC capacity will lead by the Asian players which presents highest integration capacity among the downstream players and have been investing heavily to maximize the petrochemicals yield in their refining assets, including crude to chemicals refineries. The Asian players will add close to 900 thousand barrels per day (Mbd) to the global FCC processing capacity until 2026 followed by the African players, which have been invested in FCC as part of their strategy to reduce the external dependence from high quality gasoline, in other words, differently of Asian players the addition of global FCC capacity produced by African players tends to be related to conventional and low severity FCC units with the gasoline production focus especially leaded by the new Dangote refinery in Nigeria, the Africans players will add close to 570 Mbd to the global FCC processing capacity until 2026.

Although the advantages presented by closer integration between refining and petrochemical assets, it’s important to understand that the players of downstream industry are facing with a transitive period where, as presented in Figure 1, the transportation fuels are responsible by great part of the revenues. In this business scenario, it’s necessary to define a transition strategy where the economic sustainability achieved by the current status (transportation fuels) needs to be invested to build the future (maximize petrochemicals). Keep the eyes only in the future or only in the present can be a competitive mistake.

Closing the Sustainability Cycle – Plastics Recycling Technologies

As described above, we are facing a continuous growing of petrochemicals demand and a great part of these crude oil derivatives have been applied to produce common use plastics. Despite the higher added value and significant economic advantages in comparison with transportation fuels, the main side effect of the growth of plastics consumption is the growth of plastic waste.

Despite the efforts related to the mechanic recycling of plastics, the increasing volumes of plastics waste demand most effective recycling routes to ensure the sustainability of the petrochemical industry through the regeneration of the raw material, in this sense, some technology developers have been dedicated investments and efforts to develop competitive and efficient chemical recycling technologies of plastics.

One of the most applied technologies for plastics recycling in the catalytic pyrolysis where the long chain polymeric are converted into smaller hydrocarbon molecules which can be fed to steam cracking units to reach a real circular petrochemical industry. Another route is the thermal pyrolysis of plastics, is this case, it’s possible to quote the Rewind™ Mix technology developed by Axens Company.

Another promising chemical recycling route for plastics in the hydrocracking of plastics waste, in this case the chemical principle involves the cracking of carbon-carbon bonds of the polymer under high hydrogen pressure which lead to the production of stable low boiling point hydrocarbons. The hydrocracking route present some advantages in comparison with thermal or catalytic pyrolysis, once the amount of aromatics or unsaturated molecules is lower than the achieved in the pyrolysis processes, leading to a most stable feedstock to steam cracking or another downstream processes as well as is more selective, producing gasoline range hydrocarbons which can be easily applied in the highly integrated refining hardware.

The chemical recycling of plastics is a great opportunity to technology developers and scientists, especially related to the development of effective catalysts to promote depolymerization reactions which can ensure the recovery of high added value molecules like BTX. More than that, the chemical recycling of plastics is an urgent necessity to close the sustainability cycle of an essential industry to our society.

Conclusion

The synergy between refining and petrochemical processes raises the availability of raw material to petrochemical plants and makes the supply of energy to these processes more reliable at the same time ensures better refining margin to refiners due to the high added value of petrochemical intermediates when compared with transportation fuels. Another advantage is the reduction of risks of transportation fuels oversupply, facing the current scenario of demand reduction and restriction of fossil fuels. It’s important to consider that integrated processes lead to higher operational complexity, however, given current and middle term scenarios to the refining industry, better integration between refining and petrochemical processes is fundamental to the economic sustainability of the downstream industry. In this scenario, Petrochemical FCC units can ensure a significant competitive advantage to refiners inserted in markets with high demand by petrochemicals, despite the higher capital spending in comparison with conventional FCC units. Again, it’s important to understand the transitive period faced by the downstream industry and maintain competitive operations with the current focus in transportation fuels while the transition to petrochemicals is prepared in a sustainable manner aiming to keep economic sustainability and competitiveness in the downstream market.

As presented above, the FCC technologies have a fundamental role in the new downstream industry and is expected capital investment from refiners in the next years to revamp their FCC units to maximize olefins as well as to install petrochemical FCC units to achieve higher level of petrochemical yield in the refining hardware, especially in the Asian market with present a more integrated refining park and higher demand of petrochemical intermediates. In summary, we can say that the petrochemical FCC is a relevant competitive advantage in the current scenario of the downstream industry and are expected capital investments to install new units or revamp the existing FCC units in order to ensure higher added value to the processed crude through petrochemicals maximization.

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Dr. Marcio Wagner da Silva is Process Engineering Manager at a Crude Oil Refinery based in São José dos Campos, Brazil. He earned a bachelor’s in chemical engineering from the University of Maringa (UEM), Brazil and a PhD. in Chemical Engineering from the University of Campinas (UNICAMP), Brazil. He has extensive experience in research, design and construction in the oil and gas industry, including developing and coordinating projects for operational improvements and debottlenecking to bottom barrel units, moreover Dr. Marcio Wagner earned an MBA in Project Management from the Federal University of Rio de Janeiro (UFRJ), and in Digital Transformation at Pontifical Catholic University of Rio Grande do Sul (PUC/RS), in Production and Operations Management at University of Sao Paulo (USP), and is certified in Business from Getulio Vargas Foundation (FGV).