Computer-Aided Exergy Analysis of a Creole Avocado Extractive-Based Biorefinery and Sustainable Utilization in Montes de Maria, Colombia

Abstract

Creole avocado is the second most widely produced and consumed variety of avocado globally. Due to its commercialization, limited studies have explored its potential for sustainable applications in biorefinery, particularly focusing on reusing the significant amount of waste generated during its consumption. This research evaluates thermodynamic energy losses of a Creole avocado extractive-based biorefinery, which are of critical importance during the fruit valorization process to determine the efficiency and possibilities of optimization, as well as sustainability impacts, through an exergy balance using computer-aided process engineering. The proposed method utilizes the whole fruit to produce three primary bioproducts, with a focus on implementation in the Montes de María region of Colombia. Following the extended mass and energy balance, an in-depth exergetic analysis was conducted, revealing that all process stages exhibited an exergetic efficiency exceeding 50%. The irreversibilities of the process were calculated as 7763.74 MJ/h, the total waste exergy was 2924.42 MJ/h, and the exergy from industrial waste amounted to 7800.42 MJ/h. These findings highlight the potential for optimizing the sustainability of avocado-based production systems through computer-aided analysis as an effective method. This approach accurately identifies exergy losses at each stage, providing precise numerical data and graphical representations. Additionally, it underscores not only the environmental benefits but also the contribution of these systems to enhancing energy efficiency in agro-industrial applications.

1. Introduction

The increasing demand for products, energy, and chemicals—most of which are derived from non-renewable resources—has become a major concern in the context of environmental sustainability. This has created an urgency to meet this demand using organic matter, which has shown potential to produce bio-based energy [1]. Likewise, the increase in the world’s population each year is one of the main causes of the alterations and unexpected variability of the climate observed in recent years. For this reason, for researchers, engineers and, professionals in any area of study, it is essential to incorporate sustainability criteria in decision-making. Sustainability criteria are guidelines that minimize the environmental, social, economic, and energy impacts caused by human action and industrial production processes. These criteria help slow down the changes caused by climate change, in which we are currently immersed. In addition, the multiproduct extractive-based biorefinery approach encompasses various high-value-added products while aiming for economic and sustainable profitability, for this reason. More integrated biorefineries are being developed, allowing for the selectivity of components from the main product, in this case, avocado. Similarly, the present study is supported by Sustainable Development Goal 3 of the 17 Sustainable Development Goals (SDGs) of the 2030 Agenda [1,2].

Avocado (Laurus persea L.) is widely consumed and produced around the world, with global production significantly increasing by 13.9% between 2019 and 2020. The main countries involved in its production are in Central America and the Caribbean, which account for more than 70% of global production. The Hass avocado variety dominates the market due to its nutritional benefits and shelf life [1].

The avocado is composed of a mesocarp or pulp that ranges from pale to bright yellow and has a smooth buttery texture. The skin, also known as the exocarp, is dark green or very dark green and, depending on the variety, can be smooth or rough, glossy or matte, and thin or thick. The fruit contains a single seed (endocarp) that is round or oval and ivory-colored (Figure 1). The way it is consumed often results in the disposal of the exocarp and seed in large quantities, creating an environmental issue regarding the management of these residues. Due to the composition of the avocado, these residues can be utilized to produce value-added byproducts [1,3] (see

Table 1. Chemical composition byproducts of Creole avocado.

Product	Component	Content (per 100 g)
Dried Seed	Water	60–70%
	Carbohydrates	50–60% (mainly starch)
	Fiber	20–30%
	Proteins	2–3%
	Lipids (fats)	10–15%
Mesocarp	Water	72–80%
	Calories	160 kcal
	Fats	14.66 g
	Monounsaturated fats	9.80 g
	Polyunsaturated fats	1.82 g
	Carbohydrates	8.53 g
Exocarp	Water	70–75%
	Carbohydrates	15–30%
	Fiber	10–20%
	Proteins	1–3%
	Lipids	5–10%

). In 2019, approximately 2 million tons of these residues were generated primarily from the exocarp and the seed. The presence of phenolic compounds in these residues has already been confirmed, as well as mono- and polyunsaturated fatty acids [4]. However, although high consumption is the main source of waste generation, the low efficiency throughout the entire production chain results in the deterioration of the avocado.

Compared to other avocado-producing countries like Mexico, Colombia exhibits both similarities and differences in the characteristics that enhance or hinder the efficiency of the process, making both countries key competitors. Mexico, for its part, faces greater corporate inefficiencies in areas such as economic/financial, attitude—exemplified by limited willingness to invest—and logistics/distribution. On the other hand, Colombia encounters more significant challenges in managerial/regulatory areas, such as a low or inadequate legal regulatory framework provided by cooperatives, and material/sanitary issues [5]. Recently, a comparative efficiency evaluation was conducted between avocado seeds and other biomass sources, such as sugarcane, where it was found that the avocado seed is one of the biomass sources with the highest chemical exergy due to its higher hydrogen content [6]. Furthermore, an analysis of oil extraction efficiency using various organic solvents revealed an extraction range of 60–90% oil content, with centrifugation being the stage with the greatest exergy loss, while the separation of peels and seeds demonstrated an exergetic efficiency of over 90% [7].

This research applies the concept of an extractive-based biorefinery to diagnose and propose improvements for this topology, specifically in the department of Bolívar in the Montes de María region. The proposed biorefinery focuses on utilizing advances in the energetic and exergy evaluation of the biorefinery, developing a scalable technology that meets sustainability and circular economy criteria for the comprehensive use of avocado through the process design for the production of bio-oil (mesocarp), chlorophyll (exocarp), and a biocontrol agent (seed) using computer-aided process engineering (CAPE) approach. Subsequently, the energy and exergy aspects of the biorefinery are evaluated, as well as the reagents used for the valorization of the biomass. This study is novel, as there are currently very few energy and exergy assessments addressing the sustainable utilization of value-added avocado products. Moreover, the available studies have primarily focused on the product with the highest commercial value—avocado oil—without considering the comprehensive use of the entire fruit. In Section 4, future recommendations are made based on the results obtained.

2. Materials and Methods

2.1. Process Description

The objective of the extractive-based biorefinery topology developed is the production of bio-oil, chlorophyll, and a biocontrol agent. A process simulation was previously performed and reported by the authors using Aspen Plus software (V 14), and the results of the extended mass and energy balances were used for this research. The process was divided into three sections, each corresponding to one product, along with a block diagram based on the topology modeling and the process streams, for example, the feed stream, product stream, byproduct stream, recycle stream, and purge stream. The reference conditions are 25 °C and 1 atm; the process operates in steady-state conditions. The kinetic and potential exergy flows were disregarded, as their magnitudes are not significant compared to the physical and chemical exergies, and 10,644 t/y of avocado feeds the operation.

2.1.1. Avocado Oil Extraction

For the first stage of obtaining avocado oil, the raw material, along with its impurities, undergoes a washing and drying process (Figure 2). It is washed with a sodium hypochlorite solution (stream 2) for enhanced disinfection. Subsequently, the avocado is peeled, and the mesocarp and exocarp are extracted. Two streams containing mesocarp are divided: the first stream (stream 7) directly carries the mesocarp to a homogenization stage, while the second stream (stream 8) carries another portion of the remaining mesocarp to a washing stage. After washing, the wet mesocarp proceeds to a centrifugation stage, where it merges with stream 7, creating a single stream for the homogenization stage. The outgoing mesocarp is then dried at 70 °C, after which the extraction process with methanol solvent begins. Following another centrifugation, solvent distillation, and condensation, bio-oil is obtained in stream 26 with 910.39 t/year (

Table 2. Composition of main streams of the process (Creole avocado oil extraction).

Components	Avocado and Impurities (Mass Fraction)	Washed Peel (Mass Fraction)	Homogeneous Mesocarp (Mass Fraction)	Avocado Oil (Mass Fraction)
	1	14	19	26
Methanol	0.0000	0.0000	0.0000	0.0000
Sodium hypochlorite	0.0000	0.0000	0.0000	0.0000
Water	0.6600	0.2421	0.8084	0.0000
Leucine	0.0137	0.0246	0.0095	0.0494
Glucose	0.1795	0.6706	0.0540	0.2819
Calcium oxide	0.0258	0.0120	0.0078	0.0405
Lauric	0.0000	0.0000	0.0000	0.0002
Miristic	0.0002	0.0000	0.0003	0.0014
Pentadec	0.0000	0.0000	0.0000	0.0002
Palmitic	0.0413	0.0000	0.0511	0.2664
Heptadec	0.0001	0.0000	0.0001	0.0003
Stearic	0.0013	0.0000	0.0016	0.0084
Oleic	0.0460	0.0270	0.0494	0.2578
Linoleic	0.0217	0.0000	0.0137	0.0713
Linoleum	0.0032	0.0000	0.0020	0.0106
Arachidi	0.0006	0.0000	0.0004	0.0021
Chlor	0.0027	0.0238	0.0000	0.0000
Tannin	0.0026	0.0000	0.0013	0.0067
Flavone	0.0002	0.0000	0.0001	0.0005
Phenols	0.0010	0.0000	0.0005	0.0025
Air	0.0000	0.0000	0.0000	0.0000
Acetone	0.0000	0.0000	0.0000	0.0000
Total	1.0000	1.0000	1.0000	1.0000
Specific chemical exergy of the mixture (kJ/kg)	8069.26	12,860.72	6131.31	29,338.27
Chemical exergy flow of the stream (MJ/h)	8888.81	1631.85	4848.61	2764.11
Mass exergy of the stream (MJ/h)	8888.81	1631.85	4848.61	2764.11

).

2.1.2. Chlorophyll Extraction

Chlorophyll is obtained from the exocarp after cleaning the avocado peels. These are dried at 50 °C and then subjected to grinding. For the extraction process, centrifugation and evaporation are used. During centrifugation, the extract is mixed with acetone, and a recirculated stream of acetone (stream 46) is also introduced at this stage. After centrifugation, the exocarp is separated, leaving only the chlorophyll–acetone extract (stream 42). Through evaporation at 40 °C, acetone is separated (stream 43) and recirculated—but only after undergoing condensation for recovery, purification, and improved energy efficiency—before returning to the extraction stage, as previously described. Finally, chlorophyll is obtained (stream 48) with a mass flow of 30.81 t/year (

Table 3. Composition in mass fraction of main streams of the process (chlorophyll extraction from Creole avocado peel).

Components	Steam (Mass Fraction)	Milled Peel (Mass Fraction)	Acetone (Mass Fraction)	Chlorophyll Extract (Mass Fraction)
	33	36	46	48
Methanol	0.0000	0.0000	0.0000	0.0000
Sodium hypochlorite	0.0000	0.0000	0.0000	0.0000
Water	1.0000	0.1351	0.0000	0.0317
Chlorophyll	0.0000	0.0001	0.0000	0.8984
Acetone	0.0000	0.8648	1.0000	0.0699
Total	1.0000	1.0000	1.0000	1.0000
Specific chemical exergy of the mixture (kJ/kg)	50.48	27,095.67	26,022.47	27,150.14
Chemical exergy f low of the stream (MJ/h)	1.25	6914.07	5803.27	86.57
Mass exergy of the stream (MJ/h)	5.81	6914.19	5803.40	86.58

). Figure 3 shows the block diagram of the process for this stage.

2.1.3. Biocontrol Agent Extraction

The seed feed, already washed and dried at 70 °C (stream 52), goes to a crushing stage (stream 53). The crushed seed is now ready for biocontrol agent extraction, where ethanol is used once again for the extraction process. The solvent extract and seed then proceed to a filtration step to separate the solids from the solvent. Subsequently, the solvent is separated from the extract and the solvent is recirculated at high temperatures back to the extraction stage. The biocontrol agent is produced in stream 62 with 2443.13 t/year (Figure 4,

Table 4. Composition of main streams of the process (biocontrol agent extraction).

Components	Dry Seed (Mass Fraction)	Biocontrol Agent and Ethanol (Mass Fraction)	Ethanol (Mass Fraction)	Biocontrol Agent (Mass Fraction)
	52	54	60	62	Waste
Methanol	0.0000	0.0000	0.0000	0.0000	0.0024
Sodium hypochlorite	0.0000	0.0000	0.0000	0.0000	0.0002
Water	0.4901	0.2273	0.0000	0.2644	0.0002
Leucine	0.0188	0.0083	0.0000	0.0159	0.0493
Glucose	0.3401	0.1499	0.0000	0.2876	0.2812
Calcium oxide	0.0486	0.0214	0.0000	0.0411	0.0403
Oleic	0.0167	0.0074	0.0000	0.0141	0.2571
Linoleic	0.0612	0.0270	0.0000	0.0518	0.0711
Linoleum	0.0091	0.0040	0.0000	0.0077	0.0106
Arachidi	0.0018	0.0008	0.0000	0.0015	0.0021
Ethanol	0.0000	0.5479	1.0000	0.3044	0.0000
Chlor	0.0000	0.0000	0.0000	0.0000	0.0000
Tannin	0.0093	0.0041	0.0000	0.0079	0.0067
Flavone	0.0007	0.0003	0.0000	0.0006	0.0005
Phenols	0.0035	0.0015	0.0000	0.0030	0.0025
Air	0.0000	0.0000	0.0000	0.0000	0.0000
Acetone
Total	1.0000	1.0000	1.0000	1.0000	1.0000
Specific chemical exergy of the mixture (kJ/kg)	9944.03	18,596.55	26,022.47	16,295.33	31,196.49
Chemical exergy flow of the stream (MJ/h)	2596.58	9413.33	5818.81	4120.06	256.66
Mass exergy of the stream (MJ/h)	2596.58	9416.83	5820.95	4122.29	256.66

).

2.2. Exergy Analysis

Exergy analysis is a technical and qualitative assessment that uses the principles of mass and energy for the design and analysis of thermal systems through the concept of exergy [8]. Exergy analysis is a synthesis of the first and second laws of thermodynamics [9]. The main objective of an exergy analysis is to improve efficiency and reduce the energy waste of a process [10]. Through this analysis, it is possible to identify the magnitude and the main sources of inefficiencies or irreversibilities of a system and in this way determine potential points of improvement of a process.

Some authors relate exergy to the available energy or ideal work of a system. Exergy is defined according to the principles of thermodynamics as the maximum amount of useful work that can be produced by a system or a flow of matter until the system or flow reaches equilibrium with a reference environment [11]. Exergy is consumed during real processes due to irreversibilities and is conserved during ideal processes [12].

The exergy balance of a process identifies exergy flows entering and leaving the process. The exergy flows leaving can be useful exergy flows and residual exergy flows. By means of this analysis, the magnitude of exergy destruction is calculated, which at steady state is related to the net exergies from mass, work, and heat transfer as shown in the following equation:

$${Ex}_{Destroyed}={Ex}_{mass}+{Ex}_{Work}+{Ex}_{Heat}$$

(1)

The exergy associated with work if there is no change in volume is equal to the work of the system, which can be calculated using Equation (2).

$${Ex}_{Work}=W$$

(2)

Exergy of heat involves Carnot efficiency and relates to the maximum theoretical efficiency that can be obtained in a system that is operating between two temperatures (Equation (3)). Finally, the exergy related to mass flow involves physical, chemical, kinetic, and potential exergy.

$${Ex}_{Heat}=\sum \left(1-{\displaystyle \frac{Q^T}{T}}\right)Q_i$$

(3)

In most cases, kinetic and potential exergies tend to be neglected due to their small contribution to the total exergy, leaving Equation (4) only as the contribution of physical and chemical exergy [7].

$${Ex}_{mass}={Ex}_{Physical}+{Ex}_{Chemical}+{Ex}_{Kinetic}+{Ex}_{Potential }$$

(4)

The exergy rate associated with heat transfer Q at a certain temperature T represents the maximum potential work, and any remaining heat is discharged into the environment.

Considering the process data obtained through the previously performed design and simulation, we proceed to initiate the execution of the exergy analysis for the extractive-based biorefinery in the Excel environment. Initially, the operating conditions of temperature, pressure, and mass flow of each stream involved in the process are established. The physical exergies of each stream were obtained from the results of the process simulation performed in the Aspen Plus software, while the chemical exergies of the components were obtained from the literature.

For many pure components, the standard chemical exergy can be found in the literature. However, in the case of some complex chemical compounds, such as some biomasses, the estimation of the chemical exergy can be performed through some empirical correlations based on the elemental composition [13]. In the case of avocado seed components, Equation (5) was implemented to estimate the chemical exergy.

$${Ex}_{Chemical}=63.439 C+1075.633 H-86.308 O+4.14 N+190.798 S-21.1 A$$

(5)

where C, H, O, N, S, and A represent the mass percentages of carbon, hydrogen, oxygen, nitrogen, sulfur, and ash of an organic material, respectively, obtaining the specific chemical exergy in kJ/kg.

Similarly, it is possible to determine the chemical exergy of a substance using Equation (6) [7], which takes into account the Gibbs free energy of formation and the sum of the stoichiometric coefficients multiplied by the chemical exergy of the constituents of the compound [14], which can be C, H, O, and N, among others.

$${Ex}_{Chemical}={{∆G}^0}_f+{\sum }_j{v}_j{{Ex}_{Chemical}}_{-j}^0$$

(6)

where ${{Ex}_{Chemical}}_{-j}^0$ is the chemical exergy for each element present, ${{∆G}^0}_f$ is the Gibbs free energy of the entire compound, and $v_j$ is the number of atoms for each element present in the compound [15].

Table 5. Energy requirements by stages for the Creole avocado extractive-based biorefinery.

Stage	Heat Duty kW	Heat Duty MJ/h
Pulp drying	486.615	1751.81
Methanol distillation	5.43971	19.58
Oil cooling	−3.6796	−13.25
Methanol condensation	−5.5806	−20.09
Drying seed	0.00441826	0.02
Drying peel	18.1079	65.19
Acetate distillation	79.0921	284.73
Acetone condensation	−71.5456	−257.56
Bioethanol distillation	77.228	278.02
TOTAL		2412.23

shows the chemical exergies of the substances involved in the process of obtaining value-added products from the use of avocado grown in Montes de María. To evaluate the behavior of the lignocellulosic material corresponding to cellulose and hemicellulose, the chemical exergies of its constituents such as glucose and leucine were used. In the case of ashes, the chemical exergy of calcium oxide (CaO) will be used in the evaluation. Likewise, to evaluate bio-oil, the chemical exergies of the fatty acids found in this type of product are used.

Taking into account the data presented above, the specific chemical exergy of each stream is calculated by implementing Equation (7). Likewise, it was necessary to calculate the exergy by mass transfer of each of the streams, considering Equation (4), in units of MJ/h.

$${Ex}_{Chemical-Mixture}=\sum i{y}_i{{Ex}^0}_{Chemical-i}+R{T}_0\sum i{y}_{i}ln \left(y_i\right)$$

(7)

3. Results and Discussion

The exergy analysis is then carried out in stages.

Table 6. Chemical exergies of substances to produce avocado oil, chlorophyll, and a biocontrol agent.

Component	Chemical Exergy kJ/kg	R Specific (Ideal Gas Constant in Mass Units)	Molecular Weight (kg/kmol)	Source
Methanol	22.441	0.2538	32.04	[16]
Sodium hypochlorite	2.286	0.1092	74.44	[17]
Water	50	0.4518	18	[16]
Leucine	27.802	0.0620	131.17	[18]
Glucose	15.504	0.0451	180.156	[19]
Calcium oxide	2.269	0.1450	56.0774	[16]
Lauric acid	37.655	0.0406	200.31776	[20]
Myristic acid	38.43	0.0356	228.3709	[20]
Pentadecanoic acid	67.509	0.0335	242.3975	Calculated
Palmitic acid	39.581	0.0317	256.43	[20]
Heptadecanoic acid	39.970	0.030	270.45	[20]
Stearic acid	40.284	0.0285	284.48	[20]
Oleic acid	4.2067	0.0287	282.47	[21]
Linoleic acid	39.294	0.0290	280.4472	[21]
Linolenic acid	38.824	0.0292	278.43	[21]
Arachidic acid	40.860	0.0260	312.5304	[20]
Ethanol	26.022	0.1765	47.07	[19]
Chlorophyll	27.802	0.0091	893.5	[20]
Tannins	36.590	0.0441	184.04	Calculated
Flavonoids	72.192	0.0280	290.23	[20]
Phenols	42.332	0.0451	18.16	[20]
Air	527.78	0.4518	18	[19]
Acetone	31.369	0.1400	58.08	[16]

shows the calculations of the exergies for work calculated from the power of each equipment consulted with different suppliers. For the calculation of the exergy for heat, the drying stages (pulp, peel, and seed) and solvent distillation were considered.

The next step is to calculate the exergy of the industrial services entering each stage (

Table 7. Work and heat exergies of the process stages.

Stage	Power Flow (kW)	Exergy—Work (MJ/h)	Heat Input (MJ/h)	Exergy—Heat (MJ/h)
1. Avocado washing	4	14.40	0	0.00
2. Separation of peel and mesocarp	26	93.60	0	0.00
3. Seed washing	4	14.40	0	0.00
4. Homogenization and drying of mesocarp	105	378.00	1751.81	388.63
5. Oil extraction and centrifugation	115	414.00	0.00	0.00
6. Distillation and condensation of methanol	606	2181.60	52.92	11.74
7. Washing the peel	4	14.40	0	0.00
8. Drying of peel	30	108.00	65.19	14.46
9. Milled peel	100	360.00	0	0.00
10. Chlorophyll extraction and centrifugation	190	684.00	0	0.00
11. Distillation and condensation of methanol	130	468.00	542.30	120.31
12. Drying seed	275	990.00	0.02	0.00
13. Milled and sifted seed	122	439.20	0	0.00
14. Biocontrol agent extraction and centrifugation	160	576.00	0	0.00
15. Distillation and condensation of ethanol	130	468.00	278.02	61.68
Total	2001	7203.60	0	0

), which is the sum of all the work and heat flows entering the stage, and based on this value, the total input exergy and the output exergies of the products are calculated, which are the sums of the exergies associated with the mass transfer of the streams leaving each stage that contain the product(s) of interest. Any irreversible phenomenon causes a loss of exergy. Therefore, the cause of exergy destruction is the irreversibilities of the systems. Thus, the destroyed exergy quantifies the irreversibilities present in a given process in energy units. When a process presents high exergy destruction or irreversibility, there is an opportunity for lost work or wasted work potential. The irreversibilities of the process are calculated by taking the exergy inputs of the process and subtracting the exergy associated with the output stream of the products, which was the potential that was actually used. Figure 5 shows the results obtained from the different indicators of the exergy analysis.

In the analysis of this process, the greatest exergy losses (destroyed exergy) or irreversibilities were evident in stage 6 of methanol distillation and condensation, with 22.8% of destroyed exergy, stage 5 of oil extraction and centrifugation, with 16.15% of destroyed exergy, and stage 4 of pulp homogenization and drying, with 9.87% of destroyed exergy. This can be attributed to the fact that there is a drastic change in temperature in this equipment, which leads to inevitable losses due to these variations with respect to the reference state. If a small amount of acetone were present in the avocado oil stream, it would not significantly affect the exergy balance, given the similar values of specific chemical exergies for acetone (31,369.8 kJ/kg) and avocado oil (31,306.39 kJ/kg).

Table 8. Destroyed exergies of each stage (%).

	Stage	Destroyed Exergy (%)
1	Avocado wash	2%
2	Separation of husks and pulping	1%
3	Seed washing	5%
4	Pulp homogenization and drying	10%
5	Oil extraction and centrifugation	13%
6	Methanol distillation and condensation	26%
7	Peel washing	0%
8	Drying of peel	1%
9	Crushing of peel	5%
10	Chlorophyll extraction and centrifugation	9%
11	Acetone distillation and condensation	8%
12	Seed drying	6%
13	Crushing and sifting seed	6%
14	Biocontrol agent extraction and centrifugation	0%
15	Ethanol distillation and condensation	9%
	TOTAL	100%

shows the percentage of the total exergy destroyed in each stage.

The highest waste exergy is also present in stage 6 of methanol distillation and condensation, which can be attributed to the fact that, unlike the other two topologies, in the avocado bio-oil extraction topology, the solvent is not recycled back to the process, which can be improved by recycling part of the methanol and using it in the same process, which makes this stage a focus of interest for the reduction of its internal irreversibilities. Finally, stage 14 of biocontrol agent extraction and centrifugation showed the highest exergy efficiency with 99.98%. followed by stage 7 of peel washing with 99.5% and stage 2 of peel separation and pulping with 99%, also presenting the lowest percentages of exergy destroyed in the process. Likewise, the lowest exergy efficiencies are evident in stage 6 of methanol distillation and condensation, stage 5 of oil extraction and centrifugation, and stage 9 of peel crushing, with percentages of 71.57%, 77.49%, and 81.95%, respectively.

Finally, Figure 6 shows the overall behavior of the process. The overall exergy efficiency of the process is 73.79%, which is an acceptable value compared to the work performed by Gallego and collaborators, where when performing the exergy analysis of the use of Jatropha curcas (a plant containing seeds with high oil content) as an energy agent, they obtained an overall exergy efficiency of 71% [22,23]. The entire process presents an exergy efficiency of more than 50% because from the point of view of the first law, a high conversion of the energy content of the raw material fed is being carried out.

The total irreversibilities of the process are 7763.74 MJ/h, the global waste exergy is 2924.42 MJ/h, and the exergy per industrial waste obtained is 7800.42 MJ/h.

Regarding the potential improvements in the various stages of the studied biorefinery process, it is possible to explore technical enhancement alternatives and waste utilization strategies. A general estimation shows that by reducing the total irreversibilities in the avocado oil extraction section, the exergetic efficiency of the entire biorefinery could increase up to 77.19%. In the case of improved methanol recovery, the overall efficiency could rise to 84.01%, and with progressive improvements in other stages such as solvent recovery, chlorophyll extraction, and pulp drying, the overall efficiency could reach up to 90.91%. These improvement possibilities give us an idea of the exergetic resilience of the process [24].

4. Conclusions

The exergetic evaluation of a multiproduct extractive-based biorefinery using Creole–Antillean avocado was successfully carried out. Three main bioproducts were obtained, avocado oil, a biocontrol agent, and chlorophyll, which can later be given added value through an economic evaluation to determine which product is the most profitable. On the other hand, the exergies of certain compounds not found in the literature were calculated using empirical equations.

Regarding the exergetic analysis, it was observed that throughout the 15 process stages, the exergetic efficiency remained high, reaching a global 73.79% efficiency. In contrast, there was low destroyed exergy and almost zero waste exergy, indicating that the exergy of the utility products and waste does not affect the irreversibility of the process. Lastly, it is concluded that a more thorough analysis should be conducted on the methanol distillation stage in the bio-oil extraction process, as it is the stage that showed the highest irreversibilities and the lowest efficiency. It is proposed to explore options for utilizing the residual ethanol in the biocontrol agent topology. Additionally, the possible integration of some steam streams should be studied to assess the potential for cost savings by designing a more environmentally sustainable process. Regarding the possibilities of optimizing solvent recovery, it is indeed possible to recirculate stream 31 after cleaning to reduce the amount of fresh solvent in stream 22, and in general, use separation techniques that reduce the impurity percentage in the recovered solvent for both chlorophyll extraction and avocado oil extraction.