Residue Upgrading And Petrochemicals – A Essential Combination In A Competitive Refining Hardware
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<p><strong><em>Introduction and Context</em></strong></p><p>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.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQGuILBwR_UrwQ/article-inline_image-shrink_1500_2232/0/1637884642938?e=1643241600&v=beta&t=kyofOBUPyckuFkDj2xjOOoprRoD7FvvIQOWihut1G_s" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQGuILBwR_UrwQ/article-inline_image-shrink_1500_2232/0/1637884642938?e=1643241600&v=beta&t=kyofOBUPyckuFkDj2xjOOoprRoD7FvvIQOWihut1G_s" /></div><p>Figure 1 – Global Oil Demand by Derivative (Wood Mackenzie, 2020)</p><p> According to Figure 1, is expected a growing demand by petrochemicals while 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.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQFIa0A6QJm2uA/article-inline_image-shrink_1500_2232/0/1637884659495?e=1643241600&v=beta&t=0vsm4O5o95DWQTEXK04h4C4cOWe1psQ1ualaaxPc24A" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQFIa0A6QJm2uA/article-inline_image-shrink_1500_2232/0/1637884659495?e=1643241600&v=beta&t=0vsm4O5o95DWQTEXK04h4C4cOWe1psQ1ualaaxPc24A" /></div><p>Figure 2 – Refining Margins to Integrated and Non-Integrated Refining Hardware (Wood Mackenzie, 2020)</p><p>NCM = Net Cash Margins</p><p> The improvement in fuel efficiency, growing market of electric vehicles tend 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 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.</p><p> Facing these challenges, the search for alternatives that ensure the survival and sustainability of the refining industry became constant by refiners and technology developers. Due to his similarities, better integration between refining and petrochemical production processes appears as an attractive alternative. Although the advantages, it’s important 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.</p><p>Beyond the trend of reduction in transportation fuels demand, the bottom barrel products like maritime fuel oil (bunker) have been the focus of increasingly restrictive regulations aiming to control the emissions of gases like SOx and NOx.</p><p> One of the most impacting regulations to the downstream industry in the current and short-term scenario is the necessity to reduce the sulfur content in the maritime fuels, known as IMO 2020, this regulation established which from the maximum sulfur content in the maritime transport fuel oil (Bunker) is 0,5 % (m.m) against the previously 3,5 % (m.m). The main objective is to reduce the SOx emissions from maritime fleet, significantly decreasing the environmental impact of this business. </p><p> The maritime fuel oil, known as bunker, is a relatively low viscosity fuel oil applied in diesel cycle engines to ships movement. Before 2020, the bunker was produced through the blending of residual streams as vacuum residue and deasphalted oil with dilutants like heavy gasoil and light cycle oil (LCO), due to the new regulation, a major part of the refiners will not be capable to produce low sulfur bunker through simple blend.</p><p> Due be produced from residual streams with high molecular weight, there is a tendency of contaminants accumulation (sulfur, nitrogen, and metals) in the bunker, this fact makes difficult meet the new regulation without additional treatment steps, what should lead to increasing the production cost of this derivative and the necessity to modifications in the refining schemes of some refineries. Figure 3 presents a schematic diagram of how the bunker is produced.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQH0gIfLtFH2bw/article-inline_image-shrink_1000_1488/0/1637884696753?e=1643241600&v=beta&t=US6DvKIOOVOZizgO-jlDmgxrglUw48DOZM_DaVrOOHk" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQH0gIfLtFH2bw/article-inline_image-shrink_1000_1488/0/1637884696753?e=1643241600&v=beta&t=US6DvKIOOVOZizgO-jlDmgxrglUw48DOZM_DaVrOOHk" /></div><p>Figure 3 – Bunker Production Process Before the IMO 2020</p><p> The drastic reduction of sulfur content in the final product, lead refiners to look for alternatives to reduce the sulfur content in the intermediate streams. This scenario creates great pressure over the refining margins, especially to refiners relying on refining hardware with low complexity and offer significant competitive advantage to refiners capable to ensure added value to bottom barrel streams and maximize petrochemicals.</p><p><strong><em>Changing the Focus – More Petrochemicals and less Fuels</em></strong></p><p>In this business environment it’s possible to adapt the Anssoff Matrix to considering the contraction profile of transportation fuels market to analyze the available alternatives to the downstream players, the Anssof Matrix is presented in Figure 4.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQHScvEnl5CDpA/article-inline_image-shrink_1000_1488/0/1637884723977?e=1643241600&v=beta&t=VYCfRFqFvwELdYd6jp3aTllwa35lgjqbqzNLn5SOSL0" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQHScvEnl5CDpA/article-inline_image-shrink_1000_1488/0/1637884723977?e=1643241600&v=beta&t=VYCfRFqFvwELdYd6jp3aTllwa35lgjqbqzNLn5SOSL0" /></div><p>Figure 4 – Adapted Ansoff Matrix to an in Contraction Market (Based on ROGERS, 2016)</p><p>In Figure 4 the current position of downstream players is focused on transportation fuels demand that present a contraction profile as aforementioned. In this scenario there are three alternatives to the players:</p><p>1 – Look for new clients – This alternative seems attractive in a first look, but the stricter regulations and trend of reduction in the consumption create great pressure over the consumption of fossil fuels. The major consumers of transportation fuels are still the in developing economies like Brazil, Mexico, and India but the most efficient engines and substitute technologies like hybrid and electric vehicles tends to reduce the market growth even in these countries, furthermore, the restriction in the consumer market tends to raise the competitiveness and reduce the refining margins in these markets.</p><p>2 – Offer a new Value Addition – Face the reduction in transportation fuels, an attractive strategy to the downstream sector is to offer a new proposed value to the market through higher value addition to the processed crude oils as well as needed materials to the society with lower environmental footprint than fossil fuels. The petrochemical intermediates have higher added value to refiners and growing demand as aforementioned data, the substitution of steel is some engineering materials is an interesting way to ensure market to petrochemicals in short term, in this sense, the refiners can change the production focus from transportation fuels to petrochemicals, especially in markets like Asia and Europe where the falling in transportation fuels demand is most significant. Beyond the petrochemicals, the capacity to add value to bottom barrels streams appears like a competitive advantage.</p><p>3 – New Clients and New Value Addition – Strategically, this alternative seems the right way to follow, mainly to refiners with the most complex refining hardware. Through the promotion of closer integration with the petrochemical sector, the refiners not only offer a higher proposed value to the clients and society but can reach a new range of customers capable to ensure higher added value to the processed crude oils and lower operational costs through available synergies between refining and petrochemical assets.</p><p><strong><em>Possible Synergies between Refining and Petrochemical Assets</em></strong></p><p>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.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQG4qbMtc0VGWQ/article-inline_image-shrink_1000_1488/0/1637884745787?e=1643241600&v=beta&t=MwSOKbsDQLEDRXfrYRmrBx0u_wvRIgtaNERsQXuVnZY" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQG4qbMtc0VGWQ/article-inline_image-shrink_1000_1488/0/1637884745787?e=1643241600&v=beta&t=MwSOKbsDQLEDRXfrYRmrBx0u_wvRIgtaNERsQXuVnZY" /></div><p>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 the 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. </p><p>Figure 4 presents a block diagram that shows some integration possibilities between refining processes and the petrochemical industry. </p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQFhR9dHHH2wxw/article-inline_image-shrink_1000_1488/0/1637884767184?e=1643241600&v=beta&t=Xtk5CW25DXQEHeQE5cBHiYKagmszev7yK8KGlGX5qwg" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQFhR9dHHH2wxw/article-inline_image-shrink_1000_1488/0/1637884767184?e=1643241600&v=beta&t=Xtk5CW25DXQEHeQE5cBHiYKagmszev7yK8KGlGX5qwg" /></div><p>Figure 5 – Synergies between Refining and Petrochemical Processes</p><p> 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.</p><p> 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. </p><p> The IHS Markit Company proposed a classification of the petrochemical integration grades, as presented in Figure 6. </p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQF0mgiAHFS61g/article-inline_image-shrink_1000_1488/0/1637884792927?e=1643241600&v=beta&t=ozNjzezF_0fBEi1RtLbNe7-sPRc8m20aIUQhbwL1V8k" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQF0mgiAHFS61g/article-inline_image-shrink_1000_1488/0/1637884792927?e=1643241600&v=beta&t=ozNjzezF_0fBEi1RtLbNe7-sPRc8m20aIUQhbwL1V8k" /></div><p>Figure 6 – Petrochemical Integration Levels (IHS Markit, 2018)</p><p> 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 like ethylene, propylene, and BTX.</p><p><strong><em>Crude Oil to Chemicals Strategy – Synergy of Hydrocracking and FCC Units</em></strong></p><p> 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 7.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQHmHYCQwa6XGg/article-inline_image-shrink_1000_1488/0/1637884821058?e=1643241600&v=beta&t=TA_3dBtIlSytDXZiVM6ZAVAgszPm8zCArAKcenaZ-Ok" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQHmHYCQwa6XGg/article-inline_image-shrink_1000_1488/0/1637884821058?e=1643241600&v=beta&t=TA_3dBtIlSytDXZiVM6ZAVAgszPm8zCArAKcenaZ-Ok" /></div><p>Figure 7 – Saudi Aramco Crude Oil to Chemicals Concept (IHS Markit, 2018)</p><p>The process presented in Figure 6 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. 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.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQHkN938K_A41g/article-inline_image-shrink_1000_1488/0/1637884848460?e=1643241600&v=beta&t=tgAMjK2egQtNFB36J88VgJHO2NJcBRh-NJ_fivJAzJo" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQHkN938K_A41g/article-inline_image-shrink_1000_1488/0/1637884848460?e=1643241600&v=beta&t=tgAMjK2egQtNFB36J88VgJHO2NJcBRh-NJ_fivJAzJo" /></div><p>Figure 8 – PetroFCC™ Process Technology by UOP Company</p><p> It’s important to considering that both technologies presented in Figures 8 and 9 are based on Petrochemical FCC units that present special design due to the most severe operating conditions.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQEu0hu3RT_cOg/article-inline_image-shrink_1000_1488/0/1637884871684?e=1643241600&v=beta&t=HbM8__ZRtLH_-cjgQ8mwaaJOuNlTW8Qv9JFn3oXKvWg" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQEu0hu3RT_cOg/article-inline_image-shrink_1000_1488/0/1637884871684?e=1643241600&v=beta&t=HbM8__ZRtLH_-cjgQ8mwaaJOuNlTW8Qv9JFn3oXKvWg" /></div><p>Figure 9 – HS-FCC™ Process Technology by Axens Company</p><p>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.</p><p>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. </p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQEvLAhqX9vTRA/article-inline_image-shrink_1000_1488/0/1637884894224?e=1643241600&v=beta&t=JnAqMbA_XQ_jTNpOmbDS3CcVaYoMFJW0t0au3FQzJsI" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQEvLAhqX9vTRA/article-inline_image-shrink_1000_1488/0/1637884894224?e=1643241600&v=beta&t=JnAqMbA_XQ_jTNpOmbDS3CcVaYoMFJW0t0au3FQzJsI" /></div><p>Figure 10 – Comparative Study between Conventional FCCs and Petrochemical FCC (HS-FCC™)</p><p> 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%.</p><p> 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.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQE-7hIOeiS5Bg/article-inline_image-shrink_1000_1488/0/1637884916179?e=1643241600&v=beta&t=5ZDhxIvIeuL_5tBgTaS9N4ZpcYV9pCVhKg9TKsC4ihw" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQE-7hIOeiS5Bg/article-inline_image-shrink_1000_1488/0/1637884916179?e=1643241600&v=beta&t=5ZDhxIvIeuL_5tBgTaS9N4ZpcYV9pCVhKg9TKsC4ihw" /></div><p>Figure 11 – Olefins Maximization in the Refining Hardware with INDMAX™ FCC Technology by Chevron Lummus Global Company (SANIN, A.K., 2017)</p><p>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. </p><p>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 is necessary when the unit is designed to operate under total combustion mode due to the higher heat release rate as presented below. </p><p> C + ½ O2 → CO (Partial Combustion) ΔH = - 27 kcal/mol</p><p> C + O2 → CO2 (Total Combustion) ΔH = - 94 kcal/mol</p><p>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.</p><p><strong><em>Recovering Maximum Added Value from Bottom Barrel Streams – Deep Hydrocracking Technologies</em></strong></p><p>Although the residue upgrading technologies based on carbon rejection technologies like FCC and solvent deasphalting presents competitive advantages, the refiners processing heavier crudes can face difficulties to achieve high added value to bottom barrel streams through these technologies, especially to comply with the IMO2020. In extreme cases, despite the high performance, even the fixed bed hydrocracking technologies can be not economically effective to treat residue from heavy and extra-heavy due to the short operating lifecycle. Technologies that use ebullated bed reactors and continuum catalyst replacement allow higher campaign period and higher conversion rates, among these technologies the most known are the H-Oil and Hyvahl™ (Fixed Bed) technologies developed by Axens Company, the LC-Fining Process by Chevron-Lummus, and the Hycon™ process by Shell Global Solutions. These reactors operate at temperatures above of 450 oC and pressures until 250 bar. Figure 11 presents a typical process flow diagram for a LC-Fining™ process unit, developed by Chevron Lummus Company while the H-Oil™ process by Axens Company is presented in Figure 12.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQE6-DPS-mpOFw/article-inline_image-shrink_1000_1488/0/1637884953905?e=1643241600&v=beta&t=55mmqcXgZPs7lZd3EIbhw3SIHzSr6gAQb4KJCwFnDYo" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQE6-DPS-mpOFw/article-inline_image-shrink_1000_1488/0/1637884953905?e=1643241600&v=beta&t=55mmqcXgZPs7lZd3EIbhw3SIHzSr6gAQb4KJCwFnDYo" /></div><p>Figure 12 – Process Flow Diagram for LC-Fining™ Technology by CLG Company (MUKHERJEE & GILLIS, 2018)</p><p>Catalysts applied in hydrocracking processes can be amorphous (alumina and silica-alumina) and crystalline (zeolites) and have bifunctional characteristics, once the cracking reactions (in the acid sites) and hydrogenation (in the metals sites) occurs simultaneously. </p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQHdFVluG22Ghw/article-inline_image-shrink_1000_1488/0/1637884978505?e=1643241600&v=beta&t=6MtFinj3w8V1Jp_SOy-tZYq6UCWK1_Tw9UBMItI_tQM" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQHdFVluG22Ghw/article-inline_image-shrink_1000_1488/0/1637884978505?e=1643241600&v=beta&t=6MtFinj3w8V1Jp_SOy-tZYq6UCWK1_Tw9UBMItI_tQM" /></div><p>Figure 13 – Process Flow Diagram for H-Oil™ Process by Axens Company (FRECON et. al, 2019)</p><p>An improvement in relation of ebullated bed technologies is the slurry phase reactors, which can achieve conversions higher than 95 %. In this case, the main available technologies are the HDH™ process (Hydrocracking-Distillation-Hydrotreatment), developed by PDVSA-Intevep, VEBA-Combicracking Process (VCC)™ commercialized by KBR Company, the EST™ process (Eni Slurry Technology) developed by Italian state oil company ENI, and the Uniflex™ technology developed by UOP Company. Figure 14 presents a basic process flow diagram for the VCC™ technology by KBR Company.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQHBU042iA3k_A/article-inline_image-shrink_1000_1488/0/1637884998590?e=1643241600&v=beta&t=83l3pezdGPNRMh6eqa2yHesQc1GjNltuY121so0SCag" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQHBU042iA3k_A/article-inline_image-shrink_1000_1488/0/1637884998590?e=1643241600&v=beta&t=83l3pezdGPNRMh6eqa2yHesQc1GjNltuY121so0SCag" /></div><p>Figure 14 – Basic Process Arrangement for VCC™ Slurry Hydrocracking by KBR Company (KBR Company, 2019)</p><p> In the slurry phase hydrocracking units, the catalysts in injected with the feedstock and activated in situ while the reactions are carried out in slurry phase reactors, minimizing the reactivation issue, and ensuring higher conversions and operating lifecycle. Figure 15 presents a basic process flow diagram for the Uniflex™ slurry hydrocracking technology by UOP Company.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQG4BGSLf4TjXg/article-inline_image-shrink_1000_1488/0/1637885016784?e=1643241600&v=beta&t=wgyZfCgmA54IbmqGL5MJiLu6bo1g0D9LvJGq4vgccFI" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQG4BGSLf4TjXg/article-inline_image-shrink_1000_1488/0/1637885016784?e=1643241600&v=beta&t=wgyZfCgmA54IbmqGL5MJiLu6bo1g0D9LvJGq4vgccFI" /></div><p>Figure 15 – Process Flow Diagram for Uniflex™ Slurry Phase Hydrocracking Technology by UOP Company (UOP Company, 2019).</p><p> Other commercial technologies to slurry hydrocracking process are the LC-Slurry™ technology developed by Chevron Lummus Company and the Microcat-RC™ process by Exxon Mobil Company. Aiming to meet the new bunker quality requirements, noblest streams, normally directed to produce middle distillates can be applied to produce low sulfur fuel oil, this can lead to a shortage of intermediate streams to produce these derivatives, raising his prices. The market of high sulfur content fuel oil should strongly be reduced, due to the higher prices gap when compared with diesel, his production tends to be economically unattractive.</p><p>The capital requirement is one of the most restrictions to refiners in adopt the hydrocracking technologies both to capital and operating capital due to the necessity of larger hydrogen generation units, catalysts costs, etc. Figure 16 presents a comparison between residue upgrading alternatives related to the capital investment (CAPEX) and effectiveness in the bottom barrel processing.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img style="display: block; margin-left: auto; margin-right: auto;" src="https://media-exp1.licdn.com/dms/image/C4D12AQE9U1xIJuR9eQ/article-inline_image-shrink_1000_1488/0/1637885037272?e=1643241600&v=beta&t=oq6b-9ycoK8rSA01JKQ0giHi4p1utpifuQJeGDzrXjQ" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQE9U1xIJuR9eQ/article-inline_image-shrink_1000_1488/0/1637885037272?e=1643241600&v=beta&t=oq6b-9ycoK8rSA01JKQ0giHi4p1utpifuQJeGDzrXjQ" /></div><p>Figure 16 – Capital Spending x Residue Conversion to Residue Upgrading Technologies (Shell Catalysts and Technologies, 2019)</p><p> As presented in Figure 16, the hydrocracking technologies present a higher level of required capital spending, on the other side offer higher conversion to bottom barrel streams, a necessity to refiners processing heavy and extra-heavy crudes. According to Figure 3, the other alternatives are not effective to treating residue streams with high carbon residue and metals, common characteristics of extra-heavy crude oils. In this case, the hydrocracking alternative is the most technically adequate solution.</p><p><strong><em>Synergy of Carbon Rejection Technologies as Residue Upgrading Strategy – A Cheaper Alternative</em></strong></p><p>For the downstream players processing low sulfur crudes, the synergy between carbon rejection residue upgrading units can offer an attractive alternative to improve the bottom barrel conversion capacity. Figure 17 presents an example of refining configuration where is applied Solvent Deasphalting, FCC and Delayed Coking units, in this case the focus is maximize transportation fuels in the refining hardware.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQFgV5SGnw2Eqw/article-inline_image-shrink_1000_1488/0/1637885078916?e=1643241600&v=beta&t=LFUcEVHDnAGzGWTrcKb730sZI48Cmj5ueIS-6W-rePI" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQFgV5SGnw2Eqw/article-inline_image-shrink_1000_1488/0/1637885078916?e=1643241600&v=beta&t=LFUcEVHDnAGzGWTrcKb730sZI48Cmj5ueIS-6W-rePI" /></div><p>Figure 17 – Refining Configuration Relying on Carbon Rejection Residue Upgrading Technologies (CLARK & SILVA, 2021)</p><p> In the refining scheme presented in Figure 16, the deasphalted oil is fed to FCC unit to produce LPG, naphtha, LCO, etc. while the asphaltic residue is applied to produce fuel oil and asphalt, in some refining configurations, the asphaltic residue can be fed to the delayed conking unit. For his turn, the delayed coking unit share the vacuum residue as feedstock with the solvent deasphalting unit to produce intermediate streams that can be applied to produce light and middle distillates after the hydrotreating step, in some cases the heavy gasoil from the delayed coking units is fed to the FCC unit.</p><p>It’s fundamental to understand that in the current scenario, the combination of carbon rejection technologies, as a strategy to residue upgrading, like presented in Figure 8, is possible only to refiners with access to low sulfur crude oils, once the processes are unable to reduce drastically the sulfur content in the final derivatives, it’s necessary a great hydrotreating capacity to produce marketable crude oil derivatives. Despite this restriction, the synergy between FCC, Solvent Deasphalting, and Delayed Coking units offers relatively low capital and operating cost alternative to refiners in comparison with hydrogen addition bottom barrel upgrading alternatives as deep hydrotreating or hydrocracking units, refiners inserted in markets with high demand by transportation fuels demand can reach high yields of middle distillates (higher than 40 %) applying the refining configuration presented in Figure 17, a good result considering the relatively low capital investment when compared with Hydrocracking alternative. Refiners processing relatively low sulfur crudes (close to 0,5 % in mass) can apply the refining configuration like presented in Figure 16 to produce VLSFO (Very Low Sulfur Fuel Oil) in compliance with the IMO 2020 through single blending of atmospheric residue with middle distillates in a profitable manner.</p><p><strong><em>Synergy between Delayed Coking and Hydrocracking Units</em></strong></p><p> Some refining configurations considering the combination of delayed coking and hydrocracking technologies to ensure high bottom barrel conversion capacity, ensuring minimum fuel oil production. Figure 18 present a block diagram for Coking/Hydrocracking refining scheme. </p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQHOWw2N7Z3mHw/article-inline_image-shrink_1000_1488/0/1637885111589?e=1643241600&v=beta&t=9cqTGW_ZdL1Pie4cXsjkLJgnu4yrYFfqfby5oAHgodY" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQHOWw2N7Z3mHw/article-inline_image-shrink_1000_1488/0/1637885111589?e=1643241600&v=beta&t=9cqTGW_ZdL1Pie4cXsjkLJgnu4yrYFfqfby5oAHgodY" /></div><p>Figure 18 – Process Arrangement to a Refinery Operating Under Coking/Hydrocracking Configuration</p><p> In the case of Coking/Hydrocracking refining scheme, fuel oil production is reduced to the minimum necessary to attend the consumer market, delayed coking and hydrocracking units raise the production of high added value products, like naphtha, diesel and Jet fuel, leading to a significant rise in the refiner profitability. </p><p> The improving in the refinery conversion grade rises the complexity of the refining scheme and, despite improve the profitability, operational costs also are higher to more complex refineries, however, the higher volume and better quality of the produced derivatives produces sufficient elevation in the refining margin to cover these additional costs. </p><p> In the refining configuration shown in Figure 18, sending the heavy and light coker gas oil to hydrocracking unit it’s possible to produce high quality middle distillates like diesel and jet fuel that are high demand and added value derivatives. Figure 19 presents an estimated yield considering the combination of deep hydrocracking unit (LC-Fining by Chevron-Lummus Company) and a Delayed Coking Unit.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQETJiT8wGoqXQ/article-inline_image-shrink_1000_1488/0/1637885132591?e=1643241600&v=beta&t=dqwOCqdEDXbMCf81pxtVW_2xd1r-4VqANEtX5E5SQl8" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQETJiT8wGoqXQ/article-inline_image-shrink_1000_1488/0/1637885132591?e=1643241600&v=beta&t=dqwOCqdEDXbMCf81pxtVW_2xd1r-4VqANEtX5E5SQl8" /></div><p>Figure 19 – Estimated Yields for Bottom Barrel Conversion Units (Chevron-Lummus Company, 2018)</p><p>As presented in Figure 19, it’s possible to achieve a highlighted deep bottom barrel conversion through the synergy of Delayed Coking and Hydrocracking units. The combination of hydrogen addition and carbon rejection technologies like hydrocracking and delayed coking ensures high capacity to processing heavy and discounted crudes leading to an important competitive advantage to refiners. Despite the high bottom barrel conversion profile achieved through the synergy between hydrocracking and delayed coking technologies, there are some attention points related to the raise of cracked feeds proportion in the feedstock to hydrocracking units.</p><p><strong><em>The Deep Conversion and Highly Integrated Refining Hardware – Petrochemicals from Bottom Barrel Streams</em></strong></p><p> As aforementioned the residue upgrading units are capable to improve the quality of bottom barrel streams, the main advantage of the integration between residue upgrading and petrochemical units like steam cracking is the higher availability of feeds with better crackability characteristics.</p><p> Bottom barrel streams tend to concentrate aromatics and polyaromatics compounds that present uneconomically performance in steam cracking units due the high yield of fuel oil that presents low added value, furthermore, the aromatics tends to suffer condensation reaction in the steam cracking furnaces, leading to high rates of coke deposition that reduces the operation lifecycle and raises the operating costs. In this case deep conversion units like hydrocracking can offer higher operational flexibility.</p><p>Once cracking potential is better to paraffinic molecules, and the hydrocracking technologies can improve the H/C in the molecules converting low added value bottom streams like vacuum gasoil to high quality naphtha, kerosene and diesel the synergy between hydrocracking and steam cracking units, for example, can improve the yield of petrochemical intermediates in the refining hardware, an example of highly integrated refining configuration relying on hydrocracking is presented in Figure 19.</p><div class="slate-resizable-image-embed slate-image-embed__resize-full-width"><img src="https://media-exp1.licdn.com/dms/image/C4D12AQFsjsy21T0uKQ/article-inline_image-shrink_1000_1488/0/1637885173729?e=1643241600&v=beta&t=JRwRuhs63orpZn91KeDgYU7cRsqhtnkZh6Kgv4Y6ptw" alt="No alt text provided for this image" data-media-urn="" data-li-src="https://media-exp1.licdn.com/dms/image/C4D12AQFsjsy21T0uKQ/article-inline_image-shrink_1000_1488/0/1637885173729?e=1643241600&v=beta&t=JRwRuhs63orpZn91KeDgYU7cRsqhtnkZh6Kgv4Y6ptw" /></div><p>Figure 20 – Integrated Refining Scheme Relying on Residue Upgrading and Petrochemical Maximization Technologies (UOP, 2019)</p><p> Considering the recent trend of reduction in transportation fuels demand followed by the growth of petrochemicals market makes the presence of hydrocracking units in the refining hardware raise the availability of high quality intermediate streams capable to be converted into petrochemicals, an attractive way to maximize the value addition to processed crude oil in the refining hardware. As presented in Figure 18, the synergy between carbon rejection and hydrogen addition technologies like FCC and hydrocracking units can offer an attractive alternative, sometimes the hydrocracking and FCC technologies are faced by competitors technologies in the refining hardware due to the similarities of feed streams that are processed in these units. In some refining schemes, the mild hydrocracking units can be applied as pretreatment step to FCC units, especially to bottom barrel streams with high metals content that are severe poison to FCC catalysts, furthermore the mild hydrocracking process can reduce the residual carbon to FCC feed, raising the performance of FCC unit and improving the yield of light products like naphtha, LPG, and olefins.</p><p>Considering the great flexibility of deep hydrocracking technologies that are capable to convert feed stream varying from gas oils to residue, an attractive alternative to improve the bottom barrel conversion capacity is to process in the hydrocracking units the uncracked residue in FCC unit aiming to improve the yield of high added value derivatives in the refining hardware, mainly middle distillates like diesel and kerosene.</p><p>As aforementioned, the antifragile profile is related to options and refiners with more operational flexibility have more options available to decide how crude oil slate will be processed and what kind of derivatives will be maximized in compliance with market demand and to achieve better economic results. In this sense, considering the recent forecasts, a combination of adequate bottom barrel conversion capacity and petrochemicals maximization seems capable to offer antifragile characteristics to the players of modern downstream industry.</p><p><strong><em>Closing the Sustainability Cycle – Plastics Recycling Technologies</em></strong></p><p> 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.</p><p> 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.</p><p> One of the most applied technology 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, its possible to quote the Rewind™ Mix technology developed by Axens Company.</p><p> 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 process as well as is more selective, producing gasoline range hydrocarbons which can be easily applied in the highly integrated refining hardware.</p><p> 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 a essential industry to our society.</p><p><strong><em>Conclusion</em></strong></p><p>Nowadays, is still difficult to imagine the global energetic matrix free of fossil transportation fuels, especially for in developing economies. Despite this fact, recent forecasts, and growing demand by petrochemicals as well as the pressure to minimize the environmental impact produced by fossil fuels creates a positive scenario and acts as main driving force to closer integration between refining and petrochemical assets, in the extreme scenario the zero fuels refineries tend to grow in the middle term, especially in developed economies.</p><p>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 the 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 require 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 the petrochemical sector aiming to achieve competitiveness.</p><p>In the extreme side of the petrochemical integration trend, there are the zero fuels refineries, as quoted above, it’s still difficult to imagine the downstream market without transportation fuels, but it seems a serious trend and the players of the downstream sector need to consider the focus change in his strategic plans like opportunity and threat.</p><p>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.</p>
KR Expert - Marcio Wagner da Silva
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