The metrics used in the techno-economic assessment enabled the determination of results related to the techno-economic resilience of the mass- and energy-integrated gas oil hydrocracking process. These results were compared with other processes in the petrochemical industry.
3.1. Analysis of the Technical-Economic Evaluation of the Mass and Energy-Integrated Gas Oil Hydrocracking Process
To determine the cost of a mass and energy-integrated gas oil hydrocracking unit, and from there establish the technical-economic and financial parameters and indicators of the process, the FOB price of the equipment added after energy and mass integration was added to the value of the conventional gas oil hydrocracking unit [
13], based on the analysis of costs associated with improving fuel quality in Colombia [
24]. In this way, it was possible to obtain an estimated cost of a gas oil hydrocracking unit integrated by mass and energy in Colombia for 2022, operating with a processing capacity of 1,937,247.91 t/year, of USD 15,359,463.54.
Table 10 presents the share of each parameter in the total product cost (TPC) for the mass and energy-integrated gas oil hydrocracking process.
Based on the results presented in
Table 10, it is evident that the mass and energy-integrated gas oil hydrocracking process demands a considerably higher TPC (USD 2692.20 MM) compared to the conventional gas oil hydrocracking process (USD 2265.97 MM) [
13], due to the additional equipment costs. Additionally, the value obtained in the present study is higher than the TPC for a conventional residue fluid catalytic cracking (RFCC) process, where a value of USD 277.97 MM was obtained, which presents a less robust structure, representing approximately one eighth of the total product cost [
25].
Additionally, in
Table 10, it can be observed that the largest contribution to TPC is from utilities (U), representing approximately 50%, which is due to the high demand for energy resources required by the mass and energy-integrated gas oil hydrocracking process, mainly due to the addition of equipment, such as pumps and exchangers, after mass integration with direct recycling.
Table 11 presents the results of the technical and economic evaluation, including the required initial investment, costs related to the installation of equipment, instrumentation, piping, electrical grid, and services, as well as costs associated with land development and required civil works. Additionally, it includes costs related to legal expenses, contingencies, and contractor fees. Moreover,
Table 11 shows the fixed capital investment (FCI), working capital (WCI), start-up costs (SUC), total capital investment (TCI), FCI salvage value, and annualized fixed costs (AFC).
Based on the results presented in
Table 11, it is evident that the mass and energy-integrated gas oil hydrocracking process requires a higher TCI (USD 175.68 MM) compared to the conventional gas oil hydrocracking process (USD 174.07 MM) [
13]. Additionally, for producing hydrocarbon fuel from plastic waste, a lower TCI (USD 118 MM) was obtained than that obtained in the present study, because in the first case, only 7 stages are required [
26], but in the present investigation, 9 stages are available for the production of high-value fuels from gas oil. However, the direct production of gasoline and diesel fuels from biomass Via an integrated hydropyrolysis and hydroconversion process exhibits a higher TCI (USD 263.54 MM) than the mass and energy-integrated gas oil hydrocracking process, due to the technologies applied in the first process, specifically to the coupled hydrogen plant, which represents the largest percentage (43.2%) of the capital cost distribution by process areas [
27].
Finally,
Table 12 and
Table 13 present the results of the technical, economic, and financial indicators calculated for the mass and energy-integrated gas oil hydrocracking process. The PBP in this study was 1.41 years, while the DPBP is 2.99 years. However, in other processes, such as aviation fuel production by integrated catalytic deoxygenation and hydrothermal gasification, the PBP was estimated at approximately 3 years [
28]. That is, this process takes more than twice as long to recover the investment as the mass and energy-integrated gas oil hydrocracking process.
The GP and DGP values were higher than USD 90 million, which is positive given their considerably high values. On the other hand, the economic potentials 1 (EP1), 2 (EP2), and 3 (EP3) are also significantly high, exceeding USD 1.9 billion, USD 600 million, and USD 90 million, respectively. Given that the CCF is 0.56 years
−1, that is, less than 1 year
−1, the integrated gas oil hydrocracking process can be considered an economically attractive project. Furthermore, a satisfactory internal rate of return (IRR) of 44.81% can be observed, which is higher than the results obtained for a facility using the hydrotreating/FCC pathway for bio-oil upgrading with hydrogen production Via natural gas reforming, where the IRR is 13.3% [
29]; that is, the mass and energy-integrated gas oil hydrocracking process has a high profitability potential relative to its initial cost compared to the hydrotreating/FCC route for bio-oil upgrading.
In addition, the annual cost ratio (ACR) is 32.20 and the return on investment (ROI) is 36.97%. This latter result is higher than the return on investment (ROI) of hydrogen production from natural gas (21.63%) and methanol (19.38%) [
30], indicating that, in proportion to the capital invested, the mass and energy-integrated gas oil hydrocracking process is generating higher profits. Additionally, the mass and energy-integrated gas oil hydrocracking plant generates revenue (NPV) of US
$229.62 million, which is lower than that of a conventional suspension PVC production process (US
$395.53 million). Finally, regarding financial indicators, EBT, EBIT, and EBITDA exceeded US
$90 million, which is positive, as these are relatively high values.
3.2. Analysis of Technical-Economic Resilience Through the FP2O Methodology of the Mass and Energy-Integrated Gas Oil Hydrocracking Process
Figure 3 illustrates the technical and economic resilience of the gas oil hydrocracking process after mass and energy integration, considering factors such as plant throughput, yearly fixed costs, annual sales, annual operating costs (AOCs), and variable expenses. The break-even point (BEP) analysis seeks to determine the operating conditions at which total production costs equal process revenues. This figure provides a graphical depiction of the relationship between the process’s expenses and revenues as a function of its processing capacity. Operating well above the BEP indicates that the integrated configuration not only ensures profitability but also provides a margin of economic resilience against fluctuations in plant capacity. From a design perspective, this means that the mass and energy integration strategies adopted effectively reduce operating risks and increase the robustness of the system, allowing the process to sustain profitable performance even under suboptimal operating conditions.
In
Figure 3, annual fixed charges are shown as a horizontal line since they are essentially unaffected by processing capacity. For the mass and energy-integrated gas oil hydrocracking process analyzed, these charges total
$24,771.75 million/year. In contrast, variable charges, which amount to
$2,667,430.31 million/year for the integrated process, are graphed over the processing range. The fixed and variable costs are integrated by adding the variable charges on top of the fixed cost baseline. This results in the line representing the total annualized operating costs (AOC), which is
$2,692,202.06 million/year for the mass and energy-integrated gas oil hydrocracking process. Annual revenues, which amount to
$2,789,892.40 million/year for the integrated process, are represented by a line that starts at the origin and increases to the maximum revenue as processing capacity reaches its highest level. The point where the AOC line intersects the annual sales line is known as the break-even point (BEP). When production is below the BEP, the annual operating costs surpass the total sales, meaning the process runs at a loss. Conversely, once the BEP is exceeded, the operation becomes profitable; this is the case for the integrated gas oil hydrocracking plant analyzed.
Figure 4 illustrates the techno-economic resilience of the integrated gas oil hydrocracking process in relation to the plant’s NPV and operational lifetime, which is 20 years, as specified in
Table 9, reaching an NPV of USD 229.62 million. This means that after paying all process expenses, project revenues will yield a net value of
$229.62 million in present-day dollars. It is important to highlight that the process achieves a positive net present value a little after the fifth year, which is advantageous as it lowers the risk of a project interruption hindering the recovery of the plant’s investment.
This outcome implies that the process configuration and operating conditions are economically robust over time. The fact that the integrated hydrocracking plant achieves a positive NPV after approximately five years suggests that the design ensures a relatively short payback period, providing flexibility for process adjustments and lowering financial risk during early operation.
Figure 5,
Figure 6,
Figure 7 and
Figure 8 illustrate the technical and economic resilience of the mass and energy-integrated gas oil hydrocracking process, in relation to fluctuations in the selling prices of its five main products (light and heavy naphtha, kerosene, diesel, and LPG).
Figure 5 shows how the combined sales prices of these products correlate with EBITDA and PAT.
Figure 6 presents a comparison between the aggregate sales prices, DGP, and PAT.
Figure 7 depicts the relationship between the total product sales prices and the on-stream efficiency at BEP. Lastly,
Figure 8 contrasts the individual product prices with the corresponding on-stream efficiency at BEP.
Figure 5 shows that the EBITDA of the mass and energy-integrated gas oil hydrocracking process is more sensitive to variations in the sum of selling prices of products with respect to the PAT, due to the steeper slope. Therefore, the higher sensitivity of EBITDA to variations in the combined sales price implies that the process profitability is strongly dependent on market conditions, highlighting the importance of operational flexibility and adaptive process design. From a design perspective, this means incorporating strategies that reduce fixed operating costs and enhance energy and mass integration to buffer economic fluctuations.
The critical point in terms of the sum of selling prices of products is the intersection of EBITDA and PAT, producing deficits before USD 6.75/kg. This critical value is based on a hypothetical scenario of the gas oil hydrocracking process studied. This indicates that the process is in a profitable zone, because positive values are being obtained for EBITDA (USD 106.39 million/year) and PAT (USD 64.96 million/year) with a combined selling price of products of USD 7.01/kg. Furthermore, by contrasting the sales price at the critical point with the actual process sales price, it is possible to assess how sensitive the process is to an overall reduction in product selling prices. The greater the distance between the current process condition and the intersection point, the higher its resilience. In this situation, since both values are relatively close, the process shows a high sensitivity to any decline in the combined sales prices of the products.
Figure 6 shows that the DGP of the mass and energy-integrated gas oil hydrocracking process is more sensitive to variations in the sum of selling prices of products with respect to the PAT, due to the steeper slope. Therefore, beyond the slope comparison, these results suggest that process design and operational strategies should prioritize mechanisms that stabilize profitability against product price fluctuations. In practical terms, this could involve implementing flexible operating conditions that allow the hydrocracking unit to adapt to market variations without compromising efficiency.
In this case, the critical point in terms of the sum of selling prices of products is the intersection of DGP and PAT, producing deficits before USD 6.75/kg. This critical value is based on a hypothetical scenario of the gas oil hydrocracking process studied. This indicates that the process is in a profitable zone, because positive values are being obtained for the DGP (USD 93.53 million/year) and the PAT (USD 64.96 million/year) with a combined sales price of USD 7.01/kg. Additionally, comparing the sales price at the critical point with the sales price of the process, the sensitivity of the process to a decrease in the sales price of the products as a whole can be identified. The farther the current operating point is from the intersection, the greater the process resilience. In this scenario, both values are fairly close, indicating that the process is highly sensitive to any reduction in the sum of selling prices of products.
Three regions are shown in
Figure 7. The initial range, from USD 6.74/kg to USD 6.84/kg, shows that within this interval, the process’s on-stream efficiency at BEP is highly responsive to minor fluctuations in the combined selling price of the products. Consequently, the process exhibits low resilience in this region; even a slight reduction in product prices leads to a marked rise in on-stream efficiency at BEP, as evidenced by the asymptotic trend observed toward the
y-axis in the graph.
The second range, from USD 6.84/kg to USD 7.34/kg, is a transition region and currently hosts the mass- and energy-integrated gas oil hydrocracking process, with an on-stream efficiency at BEP of 8.96% at a sum of selling prices of products of USD 7.01/kg. An acceptable level of profitability can be achieved here because, as this is not a highly sensitive area like the first, it allows for greater operational flexibility in response to changes in sales price. Finally, in the third range, for combined sales prices above USD 7.34/kg, sharp increases in product sales price do not have a significant effect on on-stream efficiency at BEP and are no longer a dependent variable of this criterion. Hence, significant fluctuations in product selling prices within this range will not produce a noticeable effect on the on-stream efficiency at BEP.
This behavior has direct implications for process design and operation. In the first region, where the system exhibits high sensitivity, the process must be operated under strict control of both production and market conditions, since even slight decreases in selling price can make the operation economically unfeasible. This suggests the need for strategies such as dynamic pricing or adaptive control systems to maintain profitability. In contrast, operation within the second region—where the current process is located—offers a balance between economic performance and operational stability. Here, design and control decisions can prioritize reliability and preventive maintenance, as small price fluctuations do not drastically affect profitability. Finally, the third region indicates a plateau of economic robustness. In this zone, design and operational decisions can focus on long-term efficiency improvements or debottlenecking strategies rather than short-term economic responses, as variations in market prices no longer significantly influence the on-stream efficiency at BEP.
Figure 8 shows five curves related to the five main products of the mass and energy-integrated gas oil hydrocracking process. The orange curve represents diesel, the red curve represents kerosene, the green curve represents LPG, the violet curve indicates heavy naphtha, and the blue curve represents light naphtha. Each curve displays the same three regions illustrated in
Figure 7; however, the distinction lies in that
Figure 8 considers the prices of individual products separately, rather than their combined total as in
Figure 7. Based on the graph, it can be determined that the products showing the greatest sensitivity in on-stream efficiency at BEP with respect to variations in sales price of the individual products are, in descending order of sensitivity, diesel (1.54 USD/kg), kerosene (1.60 USD/kg) and heavy naphtha (1.25 USD/kg), because in these three curves with asymptotic behavior with the y axis, the process is located in the first region, which affects the profitability of the process and indicates a lower operability in the face of changes in the sales price of these three products.
On the other hand, the most resilient products are, in descending order of resilience, LPG (USD 1.14/kg) and light naphtha (USD 1.48/kg). This occurs because, in these two curves, the absence of a markedly asymptotic trend toward the y-axis places the process within the second region, where profitability remains acceptable. Ultimately, since this region is less sensitive than the first one, the process can operate with greater flexibility when facing fluctuations in the selling prices of these two products. It is worth noting that the selling prices of the products increased due to the additional expenses related to the equipment added after the mass and energy integration; in this way, expenses and profits are balanced in the mass and energy-integrated gas oil hydrocracking process.
For the highly sensitive streams (diesel, kerosene, heavy naphtha), the design implication is that the plant must include greater operational flexibility and tighter control: larger capacity margins and more precise feed and hydrogen management to avoid excursions that disproportionately erode profitability. For the more resilient products (LPG, light naphtha), the opposite holds: the process can tolerate wider operating windows and be used as a buffer to smooth profitability under price volatility.
Figure 9,
Figure 10,
Figure 11 and
Figure 12 represent the techno-economic resilience of the mass and energy-integrated gas oil hydrocracking process with the feedstock cost (gas oil, demineralized water, hydrogen, and MDEA).
Figure 9 relates feedstock cost, EBITDA, and PAT.
Figure 10 establishes a relationship between feedstock cost, DGP, and PAT.
Figure 11 compares feedstock cost to on-stream efficiency at BEP.
Figure 12 establishes a comparison between feedstock cost, IRR, and NVOC.
Figure 9 shows that the EBITDA of the mass and energy-integrated gas oil hydrocracking process is more sensitive to variations in feedstock costs with respect to the PAT, due to the steeper slope. In this case, the critical point in terms of feedstock cost is the intersection of EBITDA and PAT, producing deficits after USD 455/t. This critical value is based on a hypothetical scenario of the gas oil hydrocracking process studied. This indicates that the process is in a profitable zone, because positive values are being obtained for EBITDA (USD 106.39 million/year) and PAT (USD 64.96 million/year) with a feedstock cost of USD 424.19/t.
Furthermore, by contrasting the feedstock cost at the critical point with that of the base process, it is possible to determine how sensitive the system is to variations in feedstock expenses. The greater the distance between the current operating condition and the intersection, the more resilient the process becomes. In this scenario, both values are fairly close, indicating a high vulnerability of the process to increases in raw material costs. Therefore, beyond the comparison of slopes, this finding implies that process design and operation should focus on strategies to mitigate the economic risk associated with fluctuations in feedstock prices. Additionally, integrating alternative or blended feedstocks with lower price volatility. Thus, the observed sensitivity of EBITDA to feedstock costs highlights the need for a design that prioritizes operational flexibility and cost control measures to maintain profitability under variable market conditions.
Figure 10 shows that the DGP of the mass and energy-integrated gas oil hydrocracking process is more sensitive to variations in feedstock costs with respect to the PAT, due to the steeper slope. In this case, the critical point in terms of feedstock cost is the intersection of DGP and PAT, producing deficits after USD 460/t. This critical value is based on a hypothetical scenario of the gas oil hydrocracking process studied. This indicates that the process is in a profitable zone, because positive values are obtained for the DGP (USD 93.53 million/year) and PAT (USD 64.96 million/year) with a feedstock cost of USD 424.19/kg. Additionally, by comparing the feedstock cost at the critical point with that of the actual process, it is possible to assess how sensitive the system is to rising feedstock prices. The greater the distance between the current process condition and the intersection, the higher the resilience of the system. In this situation, both values are fairly similar, indicating that the process is highly susceptible to increases in raw material costs.
This finding implies that, from a process design and operation perspective, maintaining a stable and cost-efficient feedstock supply is critical to preserving profitability. The high sensitivity of the DGP to feedstock cost variations suggests that even moderate increases in raw material prices can significantly affect the economic performance of the plant. Therefore, design strategies such as feedstock flexibility, optimization of hydrogen consumption, and enhanced heat and mass integration should be prioritized to mitigate the impact of feedstock cost fluctuations. Operationally, continuous monitoring of feedstock quality and dynamic adjustment of process conditions could help sustain favorable margins despite market volatility.
Figure 11 shows three ranges. In the first range (USD 0/t—USD 300/t), sharp decreases in feedstock costs have no significant effect on on-stream efficiency at BEP and are no longer a dependent variable of this criterion. Hence, if feedstock costs experience significant rises or drops within this range, no noticeable effect on the on-stream efficiency at BEP will be observed. The second range (USD 300/t–USD 430/t) is a transition region and currently hosts the mass- and energy-integrated gas oil hydrocracking process, with an on-stream efficiency at BEP of 8.96% at a feedstock cost of USD 424.19/t. An acceptable level of profitability can be achieved here because, as it is not a very sensitive area like the first, it allows for greater operability in the face of changes in feedstock costs. Finally, the third range, corresponding to raw material costs above USD 430/t, shows that, in this region, the on-stream efficiency at BEP becomes highly sensitive to even minor variations in feedstock cost. Consequently, the process exhibits low resilience in this zone; in other words, a slight rise in raw material cost results in a significant increase in the on-stream efficiency at the BEP. This behavior is clearly reflected in the graph, which displays an asymptotic trend toward the
y-axis.
This behavior has important implications for process design and operation. In the first region, where changes in feedstock cost have little to no impact on on-stream efficiency at BEP, the process can be considered economically stable; therefore, operating strategies can prioritize maximizing throughput or optimizing energy use without requiring frequent economic adjustments. In the transition region, the process should be closely monitored, as moderate variations in feedstock cost can begin to affect profitability; this suggests the need for flexible operating policies, such as reaction control. In the third region, where small increases in feedstock cost cause disproportionate losses in efficiency, the process design should incorporate preventive measures, such as feed diversification, dynamic pricing contracts, or intensified heat integration, to enhance resilience. Thus, understanding these regions supports proactive decision-making in process operation and design.
Figure 12 illustrates the relationship between the IRR, NVOC, and feedstock costs. The mass and energy-integrated gas oil hydrocracking process has a feedstock cost of USD 424.19/t (see the red bar), an NVOC of USD 1384.74/t, and an IRR of 44.81%. The economic resilience assessment shows that the IRR decreases as feedstock costs rise, whereas NVOC tends to increase with these costs. Consequently, there is an inverse correlation between NVOC and IRR. In simpler terms, when NVOCs represent a large share of the total cash flow, the IRR is likely to decline because higher operating expenses reduce net earnings and, therefore, project profitability. Conversely, when NVOCs are relatively low compared to cash flows, the IRR can improve due to the increase in net income.
This relationship implies that process design and operational strategies should aim to minimize NVOCs through enhanced heat and mass integration and optimized feedstock selection. A lower NVOC not only reduces the variable operating burden but also increases the IRR by maximizing the net cash flow. From a design standpoint, this suggests prioritizing technologies that enhance process intensification. Operationally, maintaining stable feedstock quality and implementing control systems to reduce process variability could help sustain economic resilience under fluctuating market conditions.
Figure 13 and
Figure 14 represent the technical-economic resilience of the mass and energy-integrated gas oil hydrocracking process with the plant’s processing capacity.
Figure 13 illustrates the correlation among processing capacity, yearly sales, and annual operating costs (AOCs).
Figure 14 compares the process capacity and the normalized fixed capital investments (FCIs).
Figure 13 illustrates that the AOC of the mass- and energy-integrated gas oil hydrocracking process exhibits greater sensitivity to variations in plant processing capacity than annual sales, as indicated by the steeper slope of the former compared to the latter. In this case, the critical point in terms of processing capacity is the intersection of annual sales and AOC, producing deficits after 2.2 MMt/y. This critical value is based on a hypothetical scenario of the gas oil hydrocracking process studied.
Consequently, when the processing capacity is below this threshold, the annual revenue remains higher than the AOC, representing a favorable condition. In contrast, once the break-even capacity is surpassed, the AOC becomes greater than the annual sales. This indicates that the process is in a profitable zone, because annual sales (USD 2789.89 MM/y) are higher than the AOC (USD 2692.20 MM/y) with a processing capacity of 1.94 MMt/y. Additionally, by comparing the equilibrium processing capacity with the process’s processing capacity, the process’s sensitivity to an increase in its processing capacity can be identified. The further the plant’s processing capacity deviates from the intersection point, the greater its resilience. In this scenario, both values are fairly close, indicating that the process is highly sensitive to any rise in processing capacity.
Therefore, beyond comparing the slopes of annual sales and AOC, this behavior has direct implications for process design and operation. A steeper AOC slope indicates that operating expenses increase more rapidly with plant capacity, suggesting that process optimization should focus on improving energy efficiency and resource utilization at higher throughputs. In practical terms, this means that any scale-up of the hydrocracking unit must be accompanied by design adjustments to prevent a disproportionate rise in operating costs. Operationally, maintaining the process close to the identified break-even capacity ensures economic stability, while exceeding it without structural improvements could lead to diminished profitability and reduced process resilience.
Figure 14 shows an inverse relationship between normalized fixed costs and processing capacity in a mass and energy-integrated gas oil hydrocracking plant. The integrated system was considered to operate at a capacity of 1.94 MMt/y, with a normalized FCI of
$3.01 per million tons (MMt). Fixed costs do not vary with production volume, meaning that as capacity expands, these costs are distributed over a greater number of units. Consequently, the fixed cost per unit decreases with higher output, contributing to a reduction in overall unit costs.
The inverse relationship between normalized fixed costs and processing capacity implies that scaling up the hydrocracking plant can significantly improve economic efficiency. From a process design standpoint, this suggests that larger, integrated plants benefit from economies of scale, where the capital and fixed operational expenses are distributed over a greater production volume. In this sense, process integration and capacity optimization must be balanced with reliability and flexibility to ensure that the plant consistently operates near its design capacity. This insight supports decisions related to plant sizing.
Figure 15 and
Figure 16 show the technical-economic resilience of the mass and energy-integrated gas oil hydrocracking process concerning NVOC.
Figure 15 relates NVOC and ROI, and
Figure 16 compares NVOC with PBP.
Figure 15 shows the influence of Normalized Variable Operating Costs (NVOC), such as utilities, maintenance and repair, labor, supervision, among others, on the process’s Return on Investment (ROI) percentage. The graph shows a strong linear dependence of the ROI on variable costs, which have a critical value around
$1435 per ton, beyond which the ROI becomes zero. This critical value is based on a hypothetical scenario of the gas oil hydrocracking process studied.
In the analyzed mass and energy-integrated gas oil hydrocracking process, the obtained value differs slightly from the present NVOC ($1384.74/t). This variation causes a modest extension of the indicator, thereby reducing the process’s resilience to fluctuations in VOC. Conversely, evaluating the opposite vertex of the triangle reveals that the process could theoretically reach a maximum ROI of 100% if the NVOC approach approximately $1296/t. The ROI value obtained in the mass and energy-integrated gas oil hydrocracking plant (36.97%) is greater than 30%, which reinforces the high economic potential of process optimization.
This behavior indicates that the gas oil hydrocracking process is slightly sensitive to variations in operating costs, meaning that any deviation from the current NVOC affects profitability. From a design and operational standpoint, this implies that special attention should be given to improving energy efficiency, optimizing utility consumption, and implementing preventive maintenance strategies to minimize variability in operating expenses. Additionally, selecting equipment and operating conditions that reduce dependence on utilities or labor-intensive operations can enhance the process’s economic resilience. In other words, process integration and optimization efforts should focus not only on maximizing ROI but also on stabilizing it against cost fluctuations, ensuring more robust and sustainable operation under real industrial conditions.
Figure 16 illustrates the PBP sensitivity and resilience assessment. A key finding is the pronounced dependence of the plant on fluctuations in the NVOC. Because of this strong influence, even small variations in operating costs can determine whether the project remains profitable or faces financial failure. Although this level of sensitivity is unfavorable, it is inevitable when processing feedstocks with highly variable prices such as gas oils. Accordingly, when the operating costs match the products’ selling price, the gross profit before taxes becomes null, preventing recovery of the FCI. Under these conditions, the PBP tends to approach infinity. For the mass- and energy-integrated gas oil hydrocracking plant evaluated, this situation arises when operating costs reach approximately US
$1425 per ton. In this so-called out-of-control region, minor changes in operating costs lead to variations in the PBP measured not in years but in decades.
Additionally, a region of relative stability can be detected for NVOC values up to approximately $1325 per tonne, and from there, a transition region can be detected until a loss of control in the process economy occurs, detecting a critical point at approximately $1400 per tonne of gas oil. The process studied is below this critical point, reaching a PBP of 1.52 years with an NVOC of $1384.74/t. This is positive because it does not take many years to recover the investment. However, being so close to the critical point value makes the process less resilient to slight changes in NVOC.
This result implies that, from a process design and operational standpoint, special attention must be given to strategies that minimize the impact of fluctuations in NVOC. In practice, this means prioritizing operating conditions and integration schemes that reduce energy consumption and feedstock losses. Moreover, since the process operates near its critical economic point, even small inefficiencies or increases in utility costs can jeopardize profitability. Therefore, incorporating control systems, optimizing maintenance schedules, and ensuring feedstock quality stability become essential to maintain process resilience and prevent economic instability.