Naphtha Molecular Management as Strategy to Face the Hostile Scenario Imposed to the Fossil Fuels

Introduction and Context

According to some recent forecasts, the petrochemical market tends to rise in the next years and, in middle term, will be responsible by a major part of the crude oil consumption over passing the transportation fuels this fact have been made the refiners to looking for closer integration with petrochemical assets through the maximization of petrochemical intermediates in their refining hardware as a strategy to ensure better refining margins and higher value addition to the crude oil. Figure 1 present an overview of the trend of growing to the petrochemical market in middle term.

Figure 1 – Growing Trend in the Demand by Petrochemical Intermediates (Wood Mackenzie, 2020)

Some of the most promising petrochemical intermediates are the aromatics benzene and p-xylene. The maximization of aromatics in the refining hardware is possible through the installation of catalytic reforming technologies associated with aromatics separation unit. The catalyst applied to catalytic reforming units have a fundamental role in the aromatics yield and consequently to allow the achievement of profitable and reliable operation.

In the current scenario of the downstream industry, the refiners are facing to important trends, the petrochemicals maximization as a strategy to ensure added value to the processed crude oil and the hydrogen question, which the refiners are facing a growing demand and environmental restrictions related to the CO2 emissions of the traditional steam reforming generation route. In this sense, the catalytic reforming units can develop a fundamental role in the strategy of some refiners.

Beyond the aromatics production, in markets with surplus of gasoline, some alternatives like blend the heavier fraction of naphtha with diesel and jet fuel can be an interesting strategy, but this alternative presents limitations due to the middle distillates specifications like volatility and Reid Vapor Pressure (RVP). In this case, technologic routes capable to manage naphtha molecules aiming to direct these streams to petrochemical intermediates can ensure closer integration with petrochemical assets as well as higher added value to refiners.

Again, being a high demand and most profitable market, the alternative to convert naphtha to petrochemicals should be a trend to refiners inserted in markets with gasoline surplus in the next years. According to data from Wood Mackenzie Company (2021), the highly integrated refiners can add from US$ 0,68 to US$ 2,02/ bbl. Still according to Wood Mackenzie, the Asian Market presents the major concentration of integrated refining plants.

It's interesting to quote the potential competitive imbalance of the downstream industry in short term due to the growing demand for petrochemicals. Based on data from 2019 the total capital investments in crude to chemicals refineries is 300 billion US dollars and 64 % of this investment was made by Asian players, to reinforce this trend Figure 4 present a comparison between the relation of crude oil distillation capacity and the integrated refinery capacity for each continent.

Figure 2 – Crude Oil Distillation Capacity and Integrated Refinery Capacity for Each Continent (Wood Mackenzie, 2023)

Figure 2 shows that the Asian players have a superior integration capacity of their refining assets in comparison with another continents, as mentioned above, this can be translated in a significant competitive advantage to the Asian players and a great potential o competitive imbalance of the downstream market considering the recent forecasts which indicates growing demand for petrochemicals. Furthermore, it’s possible to see the power of the China in the Asian and global downstream market.

As presented in Figure 3, the petrochemicals demand tends to drive the crude oil demand for the next years.

Figure 3 – Growth of Petrochemicals as Driver for Crude Oil Consumption (IEA, 2021)

Additionally, it’s important to quote that the gasoline demand will be sustained by the in developing economies, as presented in Figure 4.

Figure 4 – Growth of Gasoline Demand for the Next Years (IEA, 2021)

This fact tends to restrict the consumer market which tends to offer lower refining margins, another great advantage to refiners capable to convert naphtha to petrochemicals against gasoline.

Based on description above it’s possible to apply the article published by W. Chan Kim and Renée Mauborge called “Blue Ocean Strategy” in Harvard Business Review, to classify the competitive markets in the downstream industry. In this article the authors define the conventional market as a red ocean where the players tend to compete in the existing market focusing on defeat competitors through the exploration of existing demand, leading to low differentiation and low profitability. The blue ocean is characterized by look for space in non-explored (or few explored markets), creating and developing new demands and reaching differentiation, this model can be applied (with some specificities once is a commodity market) to the downstream industry, considering the traditional transportation fuels refineries and the petrochemical sector.

Due his characteristics, the transportation fuels market can be imagined like the red ocean, where the margins tend to be low and under high competition between the players with low differentiation capacity. On the other side the petrochemicals sector can be faced like the blue ocean where few players are able to meet the market in competitive conditions, higher refining margins, and significant differentiation in relation to refiners dedicated to transportation fuels market. Figure 5 present the basic concept of blue ocean strategy in comparison with the traditional red ocean where the players fight to market share with low margins.

Figure 5 – Differences between Blue and Red Ocean Strategies (KIM & MAUBORGNE, 2004)

As presented above, the market forecasts indicates that the refiners able to maximize petrochemicals against transportation fuels can achieve highlighted economic performance in short term, in this sense, the crude oil to chemicals technologies can offer even more competitive advantage to the refiners with capacity of capital investment.

Can be difficult to some people to understand the term “differentiation” in the downstream industry once this is a market that deal with commodities, but the differentiation here is related to the capacity to reach more added value to the processed crude oil and as presented above, nowadays this is translated in the capacity to maximize the petrochemicals yield, creating differentiation between integrated and non-integrated players.

Considering 2023 as the base year, the petrochemical market size reached a total value of USD 620,74 billion with an expected compound annual growth rate (CAGR) of 6,2 % between 2024 and 2033 as presented in Figure 6.

Figure 6 – Petrochemical Market Size Forecast 2023-2033 (Precedence Research, 2024)

Based on these data, the petrochemical market size can reach a total value of close USD 1.132,80 billion in 2033, reinforcing the attractiveness of the petrochemical market for the refiners under a scenario where the transportation fuels show in contraction demand and hostile scenario due to the necessity to reduce the carbon intensity of the energetic matrix.

Considering just the aromatics solvent market (Benzene, Toluene, and Xylenes) the CAGR expected between 2021 and 2030 is 4,8 % leading the aromatics solvent market size reach USD 8,1 billion in 2030 still according to Precedence Research data.

Maximizing Added Value to the Processed Crude – 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 7 presents a block diagram that shows some integration possibilities between refining processes and the petrochemical industry.

Figure 7 – 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, pyrolisis 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 8.

Figure 8 – 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 oil is totally converted into petrochemical intermediates.

Catalytic Reforming Technologies – Naphtha to BTX

The main objective of the Catalytic Reforming unit is to produce a stream with high aromatics hydrocarbons content that can be directed to the gasoline pool or to produce petrochemical intermediates (benzene, toluene, and xylenes) according to the market served by the refiner, due the high content of aromatics compounds the reformate can significantly raise the octane number in the gasoline, in the current scenario this a less attractive route.

A typical feedstock to the catalytic reforming unit is the straight run naphtha, however, in the last decades due to the necessity to increasing the refining margin through installation of bottom barrel units, hydrotreated coke naphtha stream has been consumed like feedstock in the catalytic reforming unit.

The catalyst generally employed in the catalytic reforming process is based on platinum (Pt) supported on alumina treated with chlorinated compounds to raise the support acidity. This catalyst has bifunctional characteristics once the alumina acid sites are actives to molecular restructuring and the metals sites are responsible for hydrogenation and dehydrogenation reactions.

The main chemical reactions involved in the catalytic reforming process are:

·       Naphthene Compounds dehydrogenation;

·       Parafinns Isomerization;

·       Isomerization of Naphthene Compounds;

·       Paraffins Dehydrocyclization;

Among the undesired reactions can be cited hydrocracking reactions and dealkylation of aromatics compounds.

Figure 9 present a basic process flow diagram for a typical semi-regenerative catalytic reforming unit.

Figure 9 – Typical arrangement to Semi-regenerative Catalytic Reforming Process Unit

The naphtha feed stream is blended with recycle hydrogen and heated at a temperature varying 500 to 550 oC before to enter in the first reactor, as the reactions are strongly endothermic the temperature fall quickly, so the mixture is heated and sent to the second reactor and so on. The effluent from the last reactor is sent to a separation drum where the phases liquid and gaseous are separated.

The gaseous stream with high hydrogen content is shared in two process streams, a part is recycled to the process to keep the ratio H2/Feed stream the other part is sent to a gas purification process plant (normally a Pressure Swing Adsorption unit) to raise the purity of the hydrogen that will be exported to others process plants in the refinery.

The liquid fraction obtained in the separation drum is pumped to a distillation column wherein the bottom is produced the reformate and in the top drum of the column is produced LPG and fuel gas.

The reformate has a high aromatics content and, according to the market supplied by the refinery, can be directed to the gasoline pool like a booster of octane number or, when the refinery has aromatics extraction plants is possible to produce benzene, toluene, and xylenes in segregated streams, which can be directed to petrochemical process plants.  The gas rich in hydrogen produced in the catalytic reforming unit is an important utility for the refinery, mainly when there is a deficit between the hydrogen production capacity and the hydrotreating installed capacity in the refinery, in some cases the catalytic reforming unit is operated with the principal objective to produce hydrogen.

The main process variables in the catalytic reforming process unit are pressure (3,5 – 30 bar), which normally is defined in the design step, in other words, the pressure normally is not an operational variable. The temperature can vary from 500 to 550 oC, the space velocity can be varied through feed stream flow rate control and the ratio H2/Feed stream that have a direct relation with the quantity of coke deposited on the catalyst during the process.  To semi-regenerative units, the ratio H2/Feed stream can vary from 8 to 10, in units with continuous catalyst regeneration this variable can be significantly reduced.

Due to the process severity, the high coke deposition rate on the catalyst and consequently the quick deactivation leaves to short operational campaign periods to semi-regenerative units that employ fixed bed reactors.

To solve this problem some technology licensors developed catalytic reforming process with continuous catalyst regeneration steps.

The process Aromizing™ developed by Axens company apply side by side configurations to the reactors while the CCR Platforming™ developed by UOP apply the configuration of stacked reactors to catalytic reforming process with continuous catalyst regeneration. Figure 10 presents a flow diagram to Aromazing™ catalytic reforming unit.

Figure 10 – Aromizing™ Reforming Technology by Axens Company

Both technologies are commercial and some process plants with these technologies are in operation around the world.  Figure 11 presents a basic process flow diagram to CCR Platforming™ developed by UOP Company.

Figure 11 – CCR Platforming™ Reforming Technology by UOP Company

In the regeneration section the catalyst is submitted to processes to burn the coke deposited during the reactions and treated with chlorinated compounds to reactivate the acid function of the catalyst.

Despite the higher capital investment, the rise in the operational campaign and higher flexibility in relation of the feedstock to be processed in the processing unit can compensate the higher investment in relation of the semi-regenerative process.

The catalytic reforming technology gives a great flexibility to the refiners in the gasoline production process, however, in the last decades there is a strong restriction on the use of reformate in the gasoline due to the control of benzene content in this derivate (due to the carcinogenic characteristics of this compound). This fact has been reduced the application of reformate in the gasoline formulation in some countries.  Furthermore, the operational costs are high, mainly due to the catalyst replacement and additional security requirements linked to minimize leaks of aromatics compounds.

Catalytic Reforming Catalysts

The catalysts applied to naphtha reforming are based on platinum carried on high purity alumina, in many cases is applied ruthenium or germanium as promoters to the catalyst activity. The catalyst has dual function, the metal site is responsible by hydrogenation and dehydrogenation reactions while the acid function, determined by the chlorine content, is responsible by the molecular arrangement reactions like paraffin cyclization, isomerization, and hydrocracking.

In some formulations, can be added Tin (Sn) to the catalyst, especially in most severe operating conditions. The tin promotes a better dispersion of platinum leading to a more selective catalyst to aromatics like xylenes, reducing the coke deposition and gases production.

As aforementioned, the main disadvantage of the semi regenerative catalytic reforming units is the relative short operating cycles due to the catalyst deactivation. The main deactivation mechanisms to catalytic reforming catalysts are the poisoning due to the contaminants in the feed, pore plugging, chemical attack to the structure, sintering, and leaching due to the catalyst cracking leading to fines production.

Regarding contaminations, the sulfur and nitrogen are temporary poison to catalytic reforming catalysts and normally the content of these contaminants is controlled through the feed hydrotreating, it’s important to quote that in some cases sulfur and nitrogen can be purposefully added to the feed to keep under control the acid function of the catalyst. As permanent poisons are quoted metals like Lead (Pb), Silicon (Si), Mercury (Hg), Copper, (Cu), Vanadium (V), etc. The poisoning involves the selective adsorption in the active sites in detriment of reactants. The metal contamination involves the chemical bond of the contaminant with platinum leading to metal alloy with activity loss, especially to dehydrogenation reactions.

The sintering is normally caused by high temperatures as well as excessive water concentration in the feed and is related to the agglomeration of metal particles reducing the active surface area.

The most common deactivation mechanism in catalytic reforming units is the coke deposition that leads to pore plugging with drastic reduction of the catalyst activity. In catalytic reforming units that rely on catalyst regeneration sections like the CCR Platforming™ by UOP Company and Aromizing™ by Axens Company, the catalyst is subjected to a sequence of process aiming to restore the catalyst activity. The first step is a controlled burning process to burn the coke deposited over the catalyst, in the sequence the catalyst crosses the oxychlorination section where is added chlorine to restore the acid function, and normally is applied perchlorethylene as chlorine source. Following the catalyst regeneration process, the catalyst is dried and cooled before to back to the process.

Due to their formulations, the catalytic reforming catalyst presents a high cost and adequate management actions are fundamental to maximize the catalyst lifecycle.

Aromatics Separation Section – Ensuring Maximum Added Value to the Naphtha

As aforementioned, in markets where there is demand, the production of petrochemical intermediates is economically more advantageous than the production of transportation fuels, especially in countries with easy access to lighter oils. The production and separation of aromatics are processes with great capacity of adding value to crude oil.

The aromatics production complex is a set of processes intended to produce petrochemical intermediates from naphtha produced in the catalytic reforming process or by pyrolysis process. An aromatics production complex can take on different process configurations, according to the petrochemical market to be served, an example is shown in Figure 12.

Figure 12 – Basic Process Configuration for a Typical Aromatics Separation Unit

The naphtha rich in aromatics, produced in catalytic reforming or pyrolysis units (in some cases from both), is fed to an extractive distillation column where the separation of aromatic compounds is conducted, which are withdrawn in the extract phase, are recovered at the bottom of the column while the non-aromatic compounds are withdrawn from the top in the raffinate phase.  The aromatics are separated from the solvent in the solvent recovery column and directed to the fractionation section of aromatics where the essentially pure benzene and toluene streams and xylenes blend are obtained. The raffinate is sent to a wash column and the non-aromatic hydrocarbons are usually sent to the refinery's gasoline pool.

The process shown in Figure 12 involves only physical separation steps, that is, the process yields in each stream depends on the concentration of this compound in the feed stream.

The growing demand for high-quality petrochemical intermediates and the higher added value of these products have made it necessary to develop conversion processes capable of converting lower interest aromatics (Toluene) into more economically attractive compounds (Xylenes).

Aromatics separation, mainly xylenes, is a great challenge to the modern engineering. The similarities between the molecules make the separation through simple distillation extremely hard, for this reason, several researchers, and technology licensors dedicate their efforts to develop new processes which can lead to pure compounds with lower costs. A basic scheme for a xylene separation process is shown in Figure 13.

Figure 13 – Basic Process for Xylenes Separation

The xylenes blend is fed to a distillation column where the ethylbenzene is separated in the top and sent to styrene production market while the bottom stream is pumped to another column where the mixture of Meta and Para-xylenes is withdrawn in the top and the Ortho-xylene and heavier compounds are removed in the bottom.

Ortho-xylene is separated from heavy aromatics in another distillation column while the Meta and Para-xylene are fed to a crystallization process, where is obtained a stream with a high concentration in Meta-xylene and the residual stream is directed to an isomerization unit, aiming to promote the conversion of residual Meta and Orto-xylenes in Para-xylene. The aromatics production units are normally optimized to maximize the Para-xylene production because this is a petrochemical intermediate with higher interest, this compound is raw material to produce terephthalic acid that is used to produce PET (Polyethylene terephthalate). Figure 14 present the chemical arrangement of the xylenes isomers.

Figure 14 – Chemical Arrangement of the Xylene Isomers

To raise the production of higher commercial and economic interest compounds (P-Xylene and Benzene), technology licensors developed several processes to convert streams with low added value in these compounds. One of the main developers of this technology is the UOP Company, the PAREX™ process apply the separation through adsorption to obtain high purity P-xylene from xylenes blend.

Another UOP technology is the ISOMAR™ process, which promotes the xylenes isomerization to Para-xylene raising the recovery of this compound in the aromatic complex. TATORAY ™ process was developed to convert toluene and heavy aromatics (C9+) in benzene and xylenes through transalkylation reaction. Another economically attractive technology is the SULPHOLANE ™ process that applies liquid-liquid extraction operations and extractive distillation to reach high purity aromatics separation from hydrocarbon mixture.

The UOP Company developed an integrated aromatics complex aiming to maximize the production of benzene and P-xylene, which lead to a higher profitability to the refiner. A UOP Aromatics Complex scheme is presented in Figure 15.

Figure 15 – Aromatics Complex by UOP Company

Other companies have attractive and efficient technologies to produce high purity aromatics, the Axens Company license an aromatics production complex also based on separation and conversion processes, called ParamaX™ that can be optimized to produce P-xylene. This process is presented in Figure 16.

The ParamaX™ technology offers the possibility of Cyclohexane production (Raw material to synthetic fibers) through benzene hydrogenation beyond raise the production of this component through toluene HydroDealkylation (HDA).

Figure 16 – Schematic Process Flow Diagram for ParamaX™ technology, by Axens Company.

As aforementioned, the capital investment to installation of aromatics production complexes is high, however, the obtained products have high added value and rely on great demand, and even the compounds with low interest can be commercialized with high margin.  In countries with easy access to light oil reserves as Saudi Arabia and United States (Tight Oil) the installation of these process plants is even more economically attractive. As presented in Figure 15, the main reactions carried out in the aromatics production process aiming to improve the yield of benzene and xylenes are the toluene transalkylation presented in Figure 16 and the toluene disproportionation, presented in Figure 17.

Figure 17 – Toluene Transalkylation Reaction

Figure 18 – Toluene Disproportionation

It’s important to quote that all technologies have molecular management process in order to improve the yield of p-Xylene, the most added value aromatic. Recent forecasts indicate the great potential growth to the BTX market in the next years, as presented in Figure 19.

Figure 19 – Evolution of Aromatics Market Size 2023 to 2034 (Precedence Research, 2024)

Considering the data from Figure 19 the market size of the BTX market can reach a total value of USD 12,66 billion in 2034 under a compound annual growth rate (CAGR) of 4,8 % between 2024 to 2034. This data reinforces the relevance of the BTX market, especially considering the hostile scenario imposed to fossil fuels like gasoline which is the most conventional destiny of naphtha in non-integrated refineries.

The Synergy between Aromatics Production Complex and Steam Cracking Units

As presented in Figure 1, light aromatics and olefins presents growing demand and high added value when compared with gasoline, in this sense, maximize the yield of these petrochemical intermediates in the refining hardware can ensure high economic result to refiners, despite the high capital spending and operation costs related to a more complex refining hardware.

Among the synergy possibilities between steam cracking and aromatics production complexes is the use of pyrolysis gasoline produced in the steam cracking units as feed stream to aromatics production complex, improving the refinery capacity to produce aromatics against gasoline. By his turn, the raffinate stream from aromatics complex can be used to improve the olefins yield in steam cracking units, mainly ethylene and propylene.

An example of refining configuration relying on the synergy between aromatics production complex and steam cracking units is presented in Figure 20.

Figure 20 – Integrated Refining Scheme Base on Aromatics Complex and Steam Cracking Units (UOP, 2019)

Considering the recent trend of reduction in transportation fuels demand followed by the growth of petrochemicals market makes the synergy between aromatics production complex and steam cracking units an attractive way to maximize the petrochemicals production in the refining hardware and achieve closer integration between refining and petrochemical assets, a growing trend in the downstream industry.

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.

The Role of Catalytic Reforming Units in the Refineries Hydrogen Balance

Demand for hydrogen raised strongly in the last decades following the necessity of hydrotreatment units installations in refineries to comply with the pressure to reduce the content of contaminants like sulfur and nitrogen in the petroleum derivates and consequently minimizing the environmental impact caused by fuels burn. This scenario became the hydrogen one of the most important production inputs in modern refineries and adequate hydrogen management actions reach strategic character to keep under control the operating costs and refining margins, contributing to economic sustainability in the downstream industry.

The hydrogen matter is one of the most important questions to the future of downstream, the growing participation of renewable raw material in the refining hardware as a decarbonization strategy tends to raise even more the hydrogen consumption. The renewable streams have a great number of unsaturations and oxygen in his molecules which lead to high heat release rates and high hydrogen consumption, this fact leads to the necessity of higher capacity of heat removal from hydrotreating reactors aiming to avoid damage to the catalysts. The main chemical reactions associated with the renewable streams hydrotreating process can be represented as below:

R-CH=CH2 + H2 → R-CH2-CH3 (Olefins Saturation)

R-OH + H2 → R-H + H2O (Hydrodeoxigenation)

Where R represents a hydrocarbon.

These characteristics lead to the necessity of higher hydrogen production capacity by the refiners as well as quenching systems of hydrotreating reactors more robust or, in some cases, the reduction of processing capacity to absorb the renewable streams. In this point it’s important to consider a viability analysis related to the use of renewables in the crude oil refineries once the higher necessity of hydrogen generation implies in higher CO2 emissions through the natural gas reforming process that is the most applied process to produce hydrogen in commercial scale.

CH4 + H2O = CO + 3H2     (Steam Reforming Reaction - Endothermic)

CO + H2O = CO2 + H2       (Shift Reaction - Exothermic)

This fact leads some technology licensors to dedicate his efforts to look for alternative routes for hydrogen production in large scale in a more sustainable manner. Some alternatives pointed can offer promising advantages:

·       Natural Gas Steam Reforming with Carbon Capture – The carbon capture technology and cost can be limiting factor among refiners;

·       Natural Gas Steam Reforming applying biogas – The main difficult in this alternative is a reliable source of biogas as well as their cost.;

·       Reverse water gas shift reaction (CO2 = H2 + CO) – One of the most attractive technologies, mainly to produce renewable syngas;

·       Electrolysis – The technology is one of the more promising to the near future.

Refiners and technology developers are looking for alternatives to produce hydrogen in industrial scale with lower CO2 emissions and some attractive routes have been considered as competitive in the future.

Despite the advantages of the green production routes of hydrogen, they are still in development and poor attractive to the most part of the refiners, in the current scenario the refiners to look for more efficient operations aiming to optimize the hydrogen balance the refining hardware as well as apply CO2 capture technologies (the blue route), in this sense an attractive alternative is to apply technologies capable to recovery hydrogen from refinery off-gases and apply control strategies capable to minimize the hydrogen losses to flare system.

As exposed above the hydrogen generation is a key matter to refiners, and refineries that rely on Catalytic Reforming units apply the hydrogen produced in this process unit to compose a relevant part of the hydrogen network becoming an important internal source of hydrogen. In some markets, where the demand by petrochemicals is lower, the main relevance of the catalytic reforming to the refining hardware is the hydrogen generation against the production of light aromatics. Figure 21 presents an example of hydrogen network in a crude oil refinery with high hydroprocessing capacity.

Figure 21 – Example of Hydrogen Network to a Crude Oil Refinery

In refineries with bottlenecked hydrogen generation units, the hydrogen from catalytic reforming units is fundamental to ensure the compliance with the current quality and environmental regulations, becoming a fundamental enabler to profitable and reliable operations of the refining hardware. Nowadays, it’s not uncommon to find refiners operating catalytic reforming units with the main objective to hydrogen generation, especially to refiners that operates with octane giveaway in the gasoline pool.

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 search to add maximum value to processed crude oil is a constant among the refiners, especially considering the competitive scenario faced by the downstream market, in this sense, the flexible refining technologies like Catalytic Reforming and aromatics recovery section can offer a significant competitive advantage.

Installation of aromatics production units can significantly raise the profitability to refiners inserted in markets with high demand for petrochemical intermediates and surplus in gasoline, this fact is especially true in the current scenario where the transportation fuels consumption suffered drastic reduction due to the economic crisis caused by the COVID 19. The catalytic reforming technologies can develop a fundamental role in the downstream industry to allow profitable and reliable operations to refiners both to maximize petrochemicals and allow closer integration with petrochemical assets and ensure a positive contribution to the hydrogen balance, reducing the necessity to higher capacity of traditional steam methane reformers with consequent lower CO2 emissions. These advantages can be even more relevant in market with great gasoline surplus aiming to ensure higher added value to the processed crude.

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. The development of crude to chemicals technologies reinforces the necessity of closer integration of refining and petrochemical assets by the brownfield refineries aiming to face the new market that tends to be focused on petrochemicals against transportation fuels, it’s important to note the competitive advantage of the refiners from Middle East that have easy access to light crude oils which can be easily applied in crude to chemicals refineries. As presented above, crude oil to chemicals refineries is based on deep conversion processes that requires high capital spending, this fact can put under pressure the refiners with restrict access of capital, again reinforcing the necessity to look for close integration with petrochemical sector aiming to achieve competitiveness.

Despite the benefits of petrochemical integration, it’s fundamental taking in mind the necessity to reach a circular economy in the downstream industry, to achieve this goal, the chemical recycling of plastics is essential. As presented above, there are promising technologies which can ensure the closing of the sustainability cycle of the petrochemical industry.

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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), in Operations and Production Management at University of Sao Paulo, and in Digital Transformation at Pontifical Catholic University of Rio Grande do Sul (PUC/RS), and is certified in Business from Getulio Vargas Foundation (FGV).