Next Article in Journal
Co-Firing of Refuse-Derived Fuel with Ekibastuz Coal in a Bubbling Fluidized Bed Reactor: Analysis of Emissions and Ash Characteristics
Previous Article in Journal
Side Fins Performance in Biomimetic Unmanned Underwater Vehicle
Previous Article in Special Issue
Biogas Production and Microbial Communities of Mesophilic and Thermophilic Anaerobic Co-Digestion of Animal Manures and Food Wastes in Costa Rica
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Techno-Economic Analysis and Life Cycle Assessment of Pineapple Leaves Utilization in Costa Rica

by
Clara Yuqi Liao
1,
Ysabel Jingyi Guan
2 and
Mauricio Bustamante-Román
3,*
1
Civil and Environmental Engineering Department, University of Michigan, Ann Arbor, MI 48109, USA
2
Physics, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USA
3
School of Biosystems Engineering, University of Costa Rica, San José 11501-2060, Costa Rica
*
Author to whom correspondence should be addressed.
Energies 2022, 15(16), 5784; https://doi.org/10.3390/en15165784
Submission received: 12 May 2022 / Revised: 16 June 2022 / Accepted: 23 June 2022 / Published: 9 August 2022

Abstract

:
Pineapple production around the world creates large amounts of wasted organic residue, mainly in the form of pineapple leaves. Current management practices consist of in situ decomposition or in situ burning, both of which cause the proliferation of flies and air pollution, respectively. The research conducted aims to develop a utilization process for this residue. Considering that pineapple leaves are rich in carbohydrates and other nutrients, a simple biological process involving a two-step procedure for juice production and ethanol fermentation has been developed to convert the leaves into renewable fuel and spent yeasts for animal feed. The liquid fraction extracted from the leaves is used as the nutrients to culture yeast, Kluyveromyces marxianus, for ethanol and yeast protein production. In Costa Rica, one of the major pineapple-producing countries in the world, the studied process can produce 92,708 and 64,859 tons of bioethanol and spent yeast per year, respectively, from its 44,500 hectares of pineapple plantation. This techno-economic analysis indicates that a regional biorefinery with the capacity to produce 50,000 metric tons per year of ethanol could have a short payback period of 4.72 years. The life cycle analysis further demonstrates the advantages of the studied biorefining concept over the current practice of open burning.

1. Introduction

Costa Rica is one of the main pineapple producers and exporters in the world. The pineapple production in Costa Rica was 2.2 million metric tons (MMT) in 2019, which was about 9.4% of the production worldwide [1]. Commercial pineapple plantations follow a 2-year fruit crop cycle. Every other year, after harvesting the fruits, the plants (mainly leaves) need to be removed or treated immediately; otherwise, the residues may cause soil contamination or be capable of hosting the larvae of stable flies (Stomoxys calcitrans), threatening the health of the local cows, sheep, pigs, and people [2]. Additionally, efforts to turn pineapple waste into animal feed are limited by storage life and arduous procedures [3]. As a result, pineapple residue is dealt with as quickly as possible, usually in the form of open burning. This practice pollutes the groundwater and affects air quality [4]. On-site decomposition, another residue removal approach, takes a long time and leaves the farms prone to pests, fire outbreaks, and diseases [5,6]. In general, an issue that plagues pineapple farms and the industry is the disposal of supposed pineapple waste in the form of inedible leaves. Thus, pineapple waste has long been dealt with as an inconvenient and useless by-product by farms.
Meanwhile, pineapple residue consists of notable levels of cellulose, hemicellulose, and soluble mono-sugars [7]. Based on a pineapple leaf utilization process developed by authors, fresh pineapple leaves can be fully utilized to produce bioethanol and animal feed at the same time, eliminating its negative environmental impacts [8]. The juice in the fresh leaves was separated for yeast ethanol production; the leftover fibers can be burned to generate power for onsite uses. The resulting spent yeast after fermentation can be used as animal feed (Figure 1). Kluyveromyces marxianus was selected to produce ethanol and yeast protein. It was selected for its admirable thermotolerance and wide breadth of materials/substances that it can process (such as lactose and xylose), as well as how quickly it grew. Additionally, K. marxianus produces different enzymes (phytase [9], β-galactosidase [10], inulinase [11], and polygalacturonases [12]) that will assist in the conversion of organic residue into valuable resources. Moreover, K. marxianus, one of the generally regarded-as-safe (GRAS) yeast species originally selected from cheese production, has potential as a probiotic yeast and as a food additive for humans and animal feed [13].
The objective of this study is to develop a technically feasible and economically pineapple residue utilization process and pioneer a path toward sustainable clean energy in organic produce markets. A comprehensive techno-economic analysis with a detailed life cycle impact assessment is conducted to conclude a regional biorefinery of pineapple leaves utilization in Costa Rica.

2. Materials and Methods

2.1. Feedstock and Location of the Biorefinery

Costa Rica has approximately 44,500 hectares of pineapple plantations across the country, generating more than 5.6 million tons of wet pineapple plant residue annually [8]. There are three main pineapple production regions in Costa Rica, the Huetar Norte region (49% of the total pineapple plantation in Costa Rica), the Atlantic Huetar region (29% of the total), and the Pacific region (22% of the total) [14]. This study selected the Huetar Norte region as the location to evaluate the economic and environmental impacts of a pineapple leaf biorefinery on the country. The pineapple residue (leaves) removed from local farms in the region are collected and transported to the biorefinery and used as the feedstock to produce fuel ethanol, electricity, and animal feed. The detailed characteristics of pineapple leaves are listed in Table 1.

2.2. The Biorefinery of Pineapple Leaf Utilization

A detailed mass and energy balance is needed to generate data for economic analysis and life cycle assessment of pineapple leaf utilization. According to the research outcomes from a previous study [8], the pineapple leaf biorefinery includes five units of operation: (1) leaf collection and transportation, (2) mechanical juice extraction, (3) juice fermentation, (4) distillation, and (5) pulp drying and combustion (Figure 1). The leaves are collected and transported to the biorefinery, where a mechanical juice extraction unit is used to extract the juice and produce pulp. Then, the pulp is dried and combusted to generate electricity in a boiler-turbine-generator system. The nutrient-rich juice is then used for yeast fermentation of ethanol and yeast biomass accumulation. The batch fermentation is carried out at a temperature of 35 °C and takes 24 h. No nutrient supplementation is required, and the pH is not regulated.
After the fermentation, yeasts are settled out, dried, and packed as protein-rich animal feed. The broth is distilled to generate fuel ethanol. The thin stillage from the distillation of the broth is dilute. The COD of the thin stillage is less than 5000 mg/L, which is much lower than the thin stillage from the corn ethanol process (ranging from 74,000 to 131,000 mg/L of COD) [15]. Traditional stillage evaporation or anaerobic digestion processes are not suitable for such a dilute stream. Therefore, the activated sludge process is adopted to treat the dilute, thin stillage before discharging. The mass and energy balance analysis is based on individual unit operations during the refining process and determines the size of individual unit operations following economic analysis and life cycle assessment.

2.3. Economic Assessment

Data from a previous study were used to conduct the techno-economic analysis (TEA) to investigate the feasibility of such a biorefining concept in Costa Rica [8]. Considering the fact that the Huetar Norte region has nearly 50% of the total pineapple plantation in Costa Rica, the size of the biorefinery is set at an annual ethanol production of 50,000 metric tons, along with electricity and yeast biomass production. Correspondingly, 3,000,000 metric tons of wet leaves (besides all pineapple residues available in the Huetar Norte region, additional 256,000 tons of biomass are shipped from nearby regions to satisfy the feedstock demand of the biorefinery) need to be collected and transported to the biorefinery. Capital expenditure (CapEx) includes individual equipment costs and added direct and indirect costs. CapExs of fermentation and distillation, utilities, and wastewater treatment are linearly scaled using daily ethanol production as the base from reference numbers [16,17]. CapEx of boiler and generator is linearly scaled using energy demand as the base from reference numbers [17]. CapExs of pulp drying and yeast drying are based on a reference CapEx number of 22 USD/kg water removed/hr for a triple-pass rotary dryer [18]. The added direct and indirect cost in the CapEx is calculated using the number of 45% of total capital investment [17]. Operating expenditure (OpEx) includes energy costs of individual unit operations, maintenance costs, and labor costs. Energy costs are calculated based on energy consumption numbers from the mass and energy balance analysis. The local electricity cost in Costa Rica is 0.15 USD/kWh. The diesel cost in Costa Rica is 0.94 USD/kg. The maintenance cost is set at 2% of the total equipment cost without considering added direct and indirect costs. Labor costs are all based on the local market price. The labor burden is set at 90% based on the current local rate. Revenues include fuel ethanol, electricity, and yeast biomass as animal feed. The electricity generated from the refinery is sold to the national grid, while residual heat of the turbine electricity generation is used for drying and distillation processes. The Modified Accelerated Cost Recovery System (MACRS) [19] a depreciation method that is used by the business in the U.S., was adopted to calculate the annual depreciation of CapEx, considering the local government allows business owners to adopt and justify their depreciation method. Annual inflation of 3.2% was set for OpEx and revenues based on the five-year average inflation rate in Costa Rica (from 2016 to 2020). The net cash flow based on depreciated CapEx, inflated OpEx, and revenues was calculated to determine the discounted payback period of the regional pineapple leaf biorefinery. In addition, a sensitivity analysis was also conducted to elucidate the effects of key unit operations on the payback period of the biorefinery.

2.4. Life Cycle Assessment

With the detailed mass and energy balance analysis, a life cycle assessment was carried out to elucidate the influences of implementing the biorefinery in Costa Rica on the reduction of carbon emission and improvement of air quality. The current pineapple leaf management practice of open burning was used as the control. Mass and energy flow from the mass and energy balance analysis are used to establish a life cycle inventory. The boundary of the life cycle assessment is from pineapple leaves after pineapple harvesting (without considering the pineapple plantation) to the end products of ethanol, dry yeast biomass, and reclaimed water. Equipment in the process and pineapple plantation are not included in this assessment. Four impact categories related to carbon emission and air quality were chosen to run a life cycle impact assessment: global warming potential (GWP), particulate matter (PM), smog potential (SP), and air acidification potential (AAP). These four parameters are used to compare impacts on carbon emission and air quality between the biorefinery solution and the current practice of open burning. The classification of each category is defined by the US Environmental Protection Agency (US EPA) [20]. The analysis was conducted using the data from EPA’s TRACI-2 characterization factors [21] and the Coordinated European Program on Particulate Matter Emission Inventories (CEPMEIP) [22]. Contribution analysis was performed to interpret the factors that influence each impact category.

3. Results and Discussion

3.1. Mass and Energy Balance

Mass and energy balance analysis was conducted on the biorefining concept of whole pineapple leaf utilization (Figure 2 and Table 2). Since the pineapple leaves available in the Huetar Norte region are within a 100 km radius (considering 12 h to harvest, collect and transport the biomass), a reference number of 200 kJ/kg wet residues was used to calculate fuel consumption for biomass collection and transportation (12 MJ/kg ethanol produced) [23]. The corresponding amount of fuel ethanol equivalent is 0.45 kg/kg ethanol produced.
Once the leaves biomass arrives at the biorefinery, the wet biomass is first crushed by an extraction unit to release nutrient-rich juice for ethanol fermentation. The mechanical extraction produces 46 kg of juice (containing 0.6 g/L and 16.4 g/L of C6 and C5 sugars, respectively) and 11 kg of wet pulp. There is 3 kg of wet leaves lost during the extraction process. The juice is also rich in proteins and other nutrients to support yeast growth for ethanol production. Mechanical juice extraction is an energy-intensive process. Energy consumption for the mechanical extraction is 23.6 MJ/kg ethanol produced (Table 2), which is the largest energy-demanding operation among all five-unit operations. From the mass balance, 60 kg of wet leaves is needed to produce 1 kg of ethanol.
The extracted juice (46 kg), without using any additional nutrients, is used for ethanol production; Kluyveromyces marxianus is the yeast strain to carry out the fermentation [8]. During a 24-h culture under 35 °C, 35 kg of fermentation broth with an ethanol content of 3.6% (v/v) and 11 kg of wet yeast are generated. Electricity and thermal energy consumptions for ethanol fermentation are 73.2 kJ/kg and 455.4 kJ/kg fermentation broth, which were calculated based on a reference [24]. Additionally, the process requires 255.0 kJ/kg fermentation broth (9 MJ/kg ethanol produced) for prior juice sterilization. Total energy consumption for ethanol fermentation is 18.5 MJ/kg ethanol produced (Table 2).
A distillation tower is then used to extract ethanol from the fermentation broth. The distillation also generates 34 kg of stillage/kg ethanol, which is then treated by a wastewater treatment operation before discharging. Based on ethanol content in the fermentation broth (3.6% v/v), an energy demand of 18.5 MJ/kg ethanol produced for the distillation was calculated according to a reference [25] (Table 2). The amount of thermal energy recovered from the distillation is 11 MJ/kg ethanol produced, which is used for the sterilization stage. The wastewater treatment operation, applying a conventional activated sludge process, needs 0.51 MJ/kg ethanol produced to treat the stillage to satisfy the discharging standard.
Meanwhile, wet pulp and wet yeast are valuable products as well. The wet pulp has relatively high contents of cellulose (37%) and hemicellulose (28%) with a high heating value of 19.4 MJ/kg dry matter, which leads to a suitable feedstock for thermal energy generation. Yeast contains proteins (22%TS), carbohydrates (16%TS), and lipid (11%TS) [8], which is a high-quality animal feed. A triple-pass rotary dryer is used to dry both pulp and yeast separately. The drying process produces 0.70 kg dry yeast and 5.50 kg dry pulp per kg ethanol produced (Figure 2). The energy demands of drying pulp and yeast are 14.7 and 26.5 MJ/kg ethanol produced, respectively (Table 2). The dry pulp is further used as the feed by a combined heat and power unit (boiler and turbo-generator) to produce steam and electricity to power the biorefinery. Due to a large amount of dry pulp, the overall energy balance of the pineapple leaf biorefinery is positive. Net surplus energy of 38.9 MJ/kg ethanol produced was generated (Table 2).
According to the mass and energy balance analysis, the entire pineapple plantation (44,500 hectares) in Costa Rica, with an annual leaf production of 5,562,500 metric tons, could produce net 92,708 metric tons of fuel ethanol, 64,859 metric tons of yeast biomass as animal feed, and 9892 TJ of potential energy generation (Table 3).

3.2. Economic Analysis

Economic feasibility is another important factor that determines the commercial applicability of such a pineapple leaf biorefinery in Costa Rica. The target biorefinery in the Huetar Norte region with an annual ethanol production of 50,000 metric tons processes 300,000 metric tons of wet leaves in the region. CapEx, OpEx, and revenues are the parameters to assess the economic performance of the biorefinery. As presented in Table 4, the CapEx to establish the studied biorefinery is USD 148,101,262 (not including the cost of land purchase or rental). Since a large amount of the pulp rich in cellulose and hemicellulose left is produced from the mechanical extraction and requires a significant power operation to handle them, the combined heat and power unit is the most expensive unit (USD 50,809,782) for the biorefinery. The wastewater treatment plant is the second most expensive unit (USD 13,501,106) because a substantial amount of the thin stillage requires a large footprint of the activated sludge unit. The total OpEx is 106,236,059 USD/year, including feedstock collection and transportation, electricity cost (electricity for the biorefinery is purchased from the grid), maintenance, and labor costs. The revenue streams of the biorefinery are ethanol, dry yeast, and electricity from pulp combustion. Ethanol as a biofuel (1.11 USD/kg), dry yeast as an animal feed additive (0.5 USD/kg), and electricity (0.15 USD/kWh) lead to total revenue of 138,727,463 USD/year, which is 1.31 times higher than the OpEx. Correspondingly, a net positive revenue of 32,491,404 USD/year is realized from the biorefinery operation.
The 5-year average local inflation of 3.2% at Costa Rica is used as the inflation rate. The depreciation period is set at 20 years. The depreciation is just on CapEx. The annual depreciation rates from MARCRS (Modified Accelerated Cost Recovery System) are 0.100, 0.188, 0.144, 0.115, 0.092, 0.074, 0.066, 0.066, 0.065, 0.065, 0.033, and 0.033 (after 10 years).
The cash flow analysis predicts that the discounted payback period of the biorefinery is 4.72 years, which is shorter than similar biorefineries [17,31]. In addition, the internal rate of return (IRR) for the project is 24.64%, and the net present value (NPV) at 10% is USD 200,764,280, showing the profitability investment of the project. A sensitivity analysis was then conducted on four key items (from both CapEx and OpEx) of the boiler and generator unit, wastewater treatment unit, collection and transportation, and juice extraction to elucidate impacts on the payback period (Table 5).
A decrement of 25% on OpEx of the juice extraction could reduce the discounted payback period by 28% (4.7 to 3.4 years), which is the largest reduction among these four key items. The reduction on OpEx of the collection and transportation can also greatly decrease the discounted payback period by 26% to 3.5 years. A 25% reduction on CapEx of the boiler/generator and wastewater treatment could shorten the discounted payback period by 17 and 4.4%, respectively. According to the sensitivity analysis, improving the efficiency of mechanical juice extraction and reducing the cost of the leaves collection and transportation are two key factors to further enhance the economic performance of the biorefinery.

3.3. Life Cycle Assessment

Based on the mass and energy balance analysis, a life cycle inventory was developed for the biorefinery (50,000 metric tons of ethanol per year) and the on-site burning (Table 6) (See Supplementary Material). According to the inventory, life cycle assessments on the four impact categories of GWP, PM, AAP, and SP were analyzed using contribution analysis [32].
The global warming potential is the amount of greenhouse gases that are released during the life cycle of the process. Since pineapple leaves are plant material, CO2 release from the combustion of the leaves is not counted as greenhouse gas emission, so CO2 emission from the on-site burning was not included in the GWP calculation.
Emission data of methane (CH4) and nitrous oxide (N2O) were normalized to a metric ton of CO2 equivalent (CO2-e) based on the following conversions: 1 kg CH4 = 21 kg CO2-e and 1 kg N2O = 310 kg CO2-e [33]. Based on the calculation, the on-site burning has an overall GWP of 44,339 metric tons of CO2-equivalent, while the biorefinery has a negative GWP of −72,965 due to the fact that the whole leaves have been processed to produce fuel, chemicals, and energy (Table 7). Distribution analysis demonstrates that N2O and CH4 from the burning contribute 56% and 44% of GWP, respectively (Figure 3). Renewable power generation and bioethanol production are the key contributors (33% and 67%, respectively) to the negative GWP of the biorefinery. This result indicates that besides value-added commodity production, the biorefining concept can efficiently reduce greenhouse gas emissions from pineapple plantations.
PM contains microscopic solids or liquid droplets that can be inhaled and cause serious health problems. Crop residue burning is one of the main PM sources. The analysis of PM demonstrates that biorefinery greatly reduces PM emission from the on-site burning of the leaves on the field (Table 7). There is no PM emission from the biorefinery since fuel ethanol is used for leaf collection and transportation. The on-site burning releases 5951 metric tons/year of PM, which has been a major environmental issue in northern Costa Rica.
AAP is the potential change of atmospheric acidity caused by the release of SO2, N2O, and NOx from biomass processing. Compounds that can cause air acidification are converted into metric ton SO2-equivalent. The AAP is calculated based on: 0.21 kg of SO2 released from burning one kg of pineapple leaves with 80% of dry matter; 0.21 kg of N2O released from burning one kg of dry pineapple leaves; and 2.6 kg of NOx released from burning one kg of dry pineapple leaves. AAP emission factors for SO2, N2O, and NOx are 1, 0.7, and 0.7, respectively. Correspondingly, the life cycle assessment shows that there is no AAP from the biorefinery. The on-site burning releases 923 metric tons per year of SO2-equivalent from the same amount of leaves used for the biorefinery (Table 7). Distribution analysis indicates that NOx from the burning is the dominant contributor (82%) to the overall AAP.
Smog is air pollution caused by the chemical reaction between sunlight, nitrogen oxides, and volatile organic compounds [34]. N2O and NOx are the main chemicals capable of smog formation with SP emission factors of 16.8 and 24.8 metric ton O3-equivalent/ton substance). The study shows again that the studied biorefinery does not generate any compounds that have SP. Currently, on-site burning produces both gases (N2O and NOx) and leads to an SP of 28,167 metric tons per year of O3-equivalent (Table 7). NOx contributes more than 94% of SP from on-site burning.
The life cycle impact assessment demonstrates the advantages of the studied biorefining concept over the current practice of open burning. The biorefining concept eliminates SP and AAP, significantly reduces PM emission and leads to a negative GWP process in handling pineapple leaves.

4. Conclusions

As one of the largest pineapple producers in the world, Costa Rica produces large amounts of fresh pineapples and pineapple plant residues. This study comprehensively analyzed the environmental and economic impacts of a biorefining concept on pineapple leaf management. Pineapple leaves were first extruded to produce juice and fibrous material. The juice was fermented by yeast, Kluyveromvces marxianus, to produce ethanol and yeast proteins. The techno-economic analysis concluded that implementing biorefining could utilize the annual leaf production of 556,250 metric tons per year in Costa Rica and produce 92,708 metric tons of fuel ethanol, 64,859 metric tons of yeast biomass as animal feed, and 2,924,872 GJ of renewable electricity. Implementing yeast production as a secondary source of income benefits the pineapple industry and overcomes the elevated cost of biomass harvest and transportation.
Correspondingly, a biorefinery operation that utilizes 50,000 metric tons per year of ethanol can generate a net revenue of 32,491,404 USD/year from products of fuel ethanol, renewable electricity, and yeast biomass. The life cycle assessment further concludes that biorefining can eliminate all negative environmental impacts currently related to the open burning of the leaves, yielding a net negative GWP and completely reducing PM emissions, AAP, and compounds containing SP. These factors all lead to a carbon-negative process. Therefore, this study concluded a technically feasible, economically sound, and environmentally friendly concept to utilize pineapple residues in Costa Rica, which will further facilitate the realization of the carbon neutrality goal and provide a technical approach to farmers to treat a residue with potential hazards to the environment and human health.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/en15165784/s1.

Author Contributions

Conceptualization, M.B.-R. and C.Y.L.; methodology, M.B.-R. and C.Y.L.; validation, M.B.-R., Y.J.G. and C.Y.L.; formal analysis, M.B.-R.; investigation, M.B.-R., Y.J.G. and C.Y.L.; data curation, M.B.-R.; writing—original draft preparation, M.B.-R. and C.Y.L.; writing—review and editing, M.B.-R., Y.J.G. and C.Y.L.; visualization, C.Y.L.; supervision, M.B.-R. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

The authors would like to thank Yan Liu and Ana Chen at Michigan State University for their technical support.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Chaves, A. Exportaciones de Piña Cayeron en el 2020, Piña de Costa Rica. 2021, p. 4. Available online: https://www.pinadecostarica.com (accessed on 14 March 2022).
  2. Solorzano, J.-A.; Gilles, J.; Bravo, O.; Vargas, C.; Gomez-Bonilla, Y.; Bingham, G.V.; Taylor, D.B. Biology and Trapping of Stable Flies (Diptera: Muscidae) Developing in Pineapple Residues (Ananas comosus) in Costa Rica. J. Insect Sci. 2015, 15, 145. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  3. Okoli, I.C. Pineapple Wastes 3: Use of Leaves, Stem, and Crown as Animal Feed. 2020. Available online: https://researchtropica.com/pineapple-wastes-3-use-of-leaves-stem-and-crown-as-animal-feed/ (accessed on 10 December 2021).
  4. Zainuddin, M.F.; Shamsudin, R.; Mokhtar, M.N.; Ismail, D. Physicochemical Properties of Pineapple Plant Waste Fibers from the Leaves and Stems of Different Varieties. Bioresources 2014, 9, 5311–5324. [Google Scholar] [CrossRef] [Green Version]
  5. Roda, A.; Lambri, M. Food uses of pineapple waste and by-products: A review. Int. J. Food Sci. Technol. 2019, 54, 1009–1017. [Google Scholar] [CrossRef]
  6. Cheok, C.Y.; Adzahan, N.M.; Rahman, R.A.; Abedin, N.H.Z.; Hussain, N.; Sulaiman, R.; Chong, G.H. Current trends of tropical fruit waste utilization. Crit. Rev. Food Sci. Nutr. 2018, 58, 335–361. [Google Scholar] [CrossRef] [PubMed]
  7. Asim, M.; Abdan, K.; Jawaid, M.; Nasir, M.; Dashtizadeh, Z.; Ishak, M.R.; Hoque, M.E. A Review on Pineapple Leaves Fibre and Its Composites. Int. J. Polym. Sci. 2015, 2015, 950567. [Google Scholar] [CrossRef] [Green Version]
  8. Chen, A.; Guan, Y.J.; Bustamante, M.; Uribe, L.; Uribe-Lorio, L.; Roos, M.M.; Liu, Y. Production of renewable fuel and value-added bioproducts using pineapple leaves in Costa Rica. Biomass Bioenergy 2020, 141, 105675. [Google Scholar] [CrossRef]
  9. Pires, E.B.E.; de Freitas, A.J.; Souza, F.F.E.; Salgado, R.L.; Guimaraes, V.M.; Pereira, F.A.; Eller, M.R. Production of Fungal Phytases from Agroindustrial Byproducts for Pig Diets. Sci. Rep. 2019, 9, 9256. [Google Scholar] [CrossRef]
  10. Alves, E.D.P.; Morioka, L.R.I.; Suguimoto, H.H. Comparison of bioethanol and beta-galactosidase production by Kluyveromyces and Saccharomyces strains grown in cheese whey. Int. J. Dairy Technol. 2019, 72, 409–415. [Google Scholar] [CrossRef]
  11. Santharam, L.; Samuthirapandi, A.B.; Easwaran, S.N.; Mahadevan, S. Modeling of exo-inulinase biosynthesis by Kluyveromyces marxianus in fed-batch mode: Correlating production kinetics and metabolic heat fluxes. Appl. Microbiol. Biotechnol. 2017, 101, 1877–1887. [Google Scholar] [CrossRef]
  12. Fonseca, G.G.; Heinzle, E.; Wittmann, C.; Gombert, A.K. The yeast Kluyveromyces marxianus and its biotechnological potential. Appl. Microbiol. Biotechnol. 2008, 79, 339–354. [Google Scholar] [CrossRef]
  13. Maccaferri, S.; Klinder, A.; Brigidi, P.; Cavina, P.; Costabile, A. Potential Probiotic Kluyveromyces marxianus B0399 Modulates the Immune Response in Caco-2 Cells and Peripheral Blood Mononuclear Cells and Impacts the Human Gut Microbiota in an In Vitro Colonic Model System. Appl. Environ. Microbiol. 2012, 78, 956–964. [Google Scholar] [CrossRef] [Green Version]
  14. CANAPEP, Estadísticas CANAPEP, 2020. Available online: https://canapep.com/estadisticas/. (accessed on 29 June 2021).
  15. Andalib, M.; Hafez, H.; Elbeshbishy, E.; Nakhla, G.; Zhu, J. Treatment of thin stillage in a high-rate anaerobic fluidized bed bioreactor (AFBR). Bioresour. Technol. 2012, 121, 411–418. [Google Scholar] [CrossRef] [PubMed]
  16. Quintero, J.A.; Cardona, C.A. Process Simulation of Fuel Ethanol Production from Lignocellulosics using Aspen Plus. Ind. Eng. Chem. Res. 2011, 50, 6205–6212. [Google Scholar] [CrossRef]
  17. Humbird, D.; National Renewable Energy Laboratory (U.S.); Harris Group Inc. Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol Dilute-Acid Pretreatment and Enzymatic Hydrolysis of Corn Stover; Nrel/Tp 5100-47764; National Renewable Energy Laboratory: Golden, CO, USA, 2011; 136p. [Google Scholar]
  18. Amos, W. Report on Biomass Drying Technology; National Renewable Energy Laboratory: Golden, CO, USA, 1998. [Google Scholar]
  19. Tax Reform Bill of 1986: Text of H.R. 3838 Reported by the Senate Finance Committee on 29 May 1986: Released 2 June 1986. Illinois: Commerce Clearing House, 1986. Available online: https://www.congress.gov/bill/99th-congress/house-bill/3838 (accessed on 1 June 2022).
  20. Curran, M. Life Cycle Assessment: Principles and Practice; Scientific Applications International Corporation (SAIC): Reston, VA, USA, 2016. [Google Scholar]
  21. Bare, J. TRACI—The Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts. J. Ind. Ecol. 2003, 6, 49–78. [Google Scholar] [CrossRef]
  22. Visschedijka, A.; Pacynab, J.; Pullesa, T.; Zandvelda, P.; Denier van der Gon, H. Coordinated European particulate matter emission inventory program (CEPMEIP). In Proceedings of the PM Emission Inventories Scientific Workshop, Lago Maggiore, Italy, 18 October 2004. [Google Scholar]
  23. Tieppo, R.C.; Andrea, M.C.S.; Gimenez, L.M.; Romanelli, T.L. Energy demand in sugarcane residue collection and transportation. Agric. Eng. Int. CIGR J. 2014, 2014, 52–58. [Google Scholar]
  24. Zanotti, M.; Ruan, Z.H.; Bustamente, M.; Liu, Y.; Liao, W. A sustainable lignocellulosic biodiesel production integrating solar- and bio-power generation. Green Chem. 2016, 18, 5059–5068. [Google Scholar] [CrossRef]
  25. Katzen, R.; Madson, P.; Moon, G., Jr. Ethanol Distillation: The Fundamentals. The Alcohol Textbook: A Reference for the Beverage, Fuel and Industrial Alcohol Industries; Jacques, K.A., Lyons, T.P., Kelsall, D.R., Eds.; Alltech Inc.: Nottingham, UK, 1999. [Google Scholar]
  26. Gu, Y.; Li, Y.; Li, X.; Luo, P.; Wang, H.; Wang, X.; Wu, J.; Li, F. Energy self-sufficient wastewater treatment plants: Feasibilities and challenges. Energy Procedia 2017, 105, 3741–3751. [Google Scholar] [CrossRef]
  27. Bustamante, M.; Liao, W. A self-sustaining high-strength wastewater treatment system using solar-bio-hybrid power generation. Bioresour. Technol. 2017, 234, 415–423. [Google Scholar] [CrossRef] [Green Version]
  28. RECOPE. Precios Vigentes, Refinadora Costarricense de Petróleo. 2022. Available online: https://www.recope.go.cr/productos/precios-nacionales/tabla-precios/ (accessed on 11 June 2022).
  29. ARESEP. Tarifas Vigentes de Electricidad, Autoridad Reguladora de los Servios Públicos. 2022. Available online: https://aresep.go.cr/electricidad/tarifas (accessed on 11 June 2022).
  30. MTSS. Lista de Salaries Mínimos del Sector Privado, Ministerio de Trabajo y Seguridad Social. 2022. Available online: https://www.mtss.go.cr/temas-laborales/salarios/lista-salarios.html (accessed on 11 June 2022).
  31. Romero-Perez, J.C.; Vergara, L.; González-Delgado, Á.D. Development of a Methodology for the Synthesis of Biorefineries Based on Incremental Economic and Exergetic Return on Investment. ACS Omega 2021, 6, 6112–6123. [Google Scholar] [CrossRef]
  32. Chen, R.; Rojas-Downing, M.M.; Zhong, Y.; Saffron, C.M.; Liao, W. Life Cycle and Economic Assessment of Anaerobic Co-digestion of Dairy Manure and Food Waste. Ind. Biotechnol. 2015, 11, 127–139. [Google Scholar] [CrossRef]
  33. IPCC. 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Prepared by the National Greenhouse Gas Inventories Programme; Eggleston, H.S., Buendia, L., Miwa, K., Ngara, T., Tanabe, K., IPCC, Eds.; Institute for Global Environmental Strategies (IGES): Hayama, Japan, 2006. [Google Scholar]
  34. CCME. NOx/VOC Fact Sheets; Canadian Council of Ministers of the Environment (CCME), Ed.; Canadian Council of Ministers of the Environment (CCME): Ottawa, ON, Canada, 1998. [Google Scholar]
  35. Prosperi, P.; Bloise, M.; Tubiello, F.N.; Conchedda, G.; Rossi, S.; Boschetti, L.; Salvatore, M.; Bernoux, M. New estimates of greenhouse gas emissions from biomass burning and peat fires using MODIS Collection 6 burned areas. Clim. Chang. 2020, 161, 415–432. [Google Scholar] [CrossRef] [Green Version]
  36. Climate Change 2014: Mitigation of Climate Change: Working Group III contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Cambridge University Press: New York, NY, USA, 2014.
  37. Darley, E.; Lerman, S. Air Pollutant Emissions from Burning Sugar Cane and Pineapple Residues from Hawaii; Environmental Protection Agency, Research Triangle Park: Research Triangle, NC, USA, 1975. [Google Scholar]
  38. Bare, J. TRACI 2.0: The tool for the reduction and assessment of chemical and other environmental impacts 2.0. Clean Technol. Environ. Policy 2011, 13, 687–696. [Google Scholar] [CrossRef]
Figure 1. Pineapple leaf biorefining *. *: The red frame is the boundary for the life cycle assessment.
Figure 1. Pineapple leaf biorefining *. *: The red frame is the boundary for the life cycle assessment.
Energies 15 05784 g001
Figure 2. Mass balance of 1 kg ethanol production from pineapple leaves.
Figure 2. Mass balance of 1 kg ethanol production from pineapple leaves.
Energies 15 05784 g002
Figure 3. Contribution of global warming potential for the biorefinery and control on-site burning (the GWP for the power does not include the ethanol product).
Figure 3. Contribution of global warming potential for the biorefinery and control on-site burning (the GWP for the power does not include the ethanol product).
Energies 15 05784 g003
Table 1. Characteristics of pineapple leaves [8].
Table 1. Characteristics of pineapple leaves [8].
ParameterLeafJuicePulp
Total solids (%)13.86.251.6
Cellulose (%TS)22.6--36.8
Hemicellulose (%TS)26.1--28.1
Lignin (%TS)7.3--5.1
Crude protein (%TS)6.9145.7
Crude fat (%TS)3.03.54.0
Potassium (%TS)2.63.760.56
Nitrogen (%TS)1.12.240.912
Phosphorus (%TS)0.110.180.08
Sulfur (%TS)0.130.210.06
Ash (%TS)6.110.021.65
Table 2. Energy balance of a regional pineapple leaf biorefinery a, b.
Table 2. Energy balance of a regional pineapple leaf biorefinery a, b.
Energy DemandEnergy (MJ/kg Ethanol Produced)
1. Leaves collection and transportation c−12.0
2. Mechanical juice extraction d−23.6
3. Fermentation e−18.5
4. Distillation f−18.5
5. Pulp drying and combustion g−14.7
6. Yeast drying g−26.5
7. Wastewater treatment of stillage h−0.51
Energy ProductionEnergy (MJ/kg Ethanol Produced)
3. Fermentation i8.9
4. Distillation j10.9
3. Distilled ethanol k26.7
5. Pulp combustion l106.7
Overall Energy Balance
Net energy m38.9
a Energy balance calculation is based on the ethanol production of 1 kg. b Negative numbers are energy demand, and positive numbers are energy generation. c The energy demands of 176 and 24 kJ/kg wet residues for leaf collection and leaf transportation, respectively, are referred from a study of sugarcane residue collection and transportation [23]. Ethanol heating value of 26.7 MJ/kg was used to calculate the fuel consumption for the pineapple leaf collection and transportation. d The electricity consumption of the mechanical juice extraction was 394 kJ/kg wet leaf [8]. e Ethanol fermentation includes seed culture and ethanol fermentation. The energy consumption of 97.7 and 54.73 kJ/kg fermentation broth for seed culture and ethanol fermentation, respectively, was calculated based on a biorefining model [24]. f The energy consumption (mainly thermal energy with 2% of parasitic electricity energy) is 18,544 kJ/kg ethanol [25]. g Triple-pass rotary dryers are used for both drying operations. The temperature of the initial biomass (pulp or yeast) is 35 °C. The drying temperature is 100°C. The specific heat capacity of water and dried biomass are 4.18 and 1.48 kJ/kg·K, respectively. The latent heat of water at 100 °C is 2244 kJ/kg. The parasitic electricity is 2% of the total thermal energy. The energy consumption was calculated based on a biorefining model [24]. h The energy demand is based on typical electricity consumption for a municipal wastewater treatment operation (0.414 kWh/m3 wastewater) [26]. The chemical oxygen demand of the stillage (5000 mg/L) is 10 times stronger than regular sewage (300–500 mg/L). The energy demand of the stillage treatment is corresponding increased to 4.14 kWh/1000 kg. i The heat recovery from the fermentation process is 60% of the thermal energy for sterilization. j The heat recovery from the distillation is 60% of the thermal energy for distillation. k The low heating value of ethanol is 26.7 MJ/kg. l The low heating value of dry pulp is 19.4 MJ/kg [8]. m Net energy—energy production–energy demand.
Table 3. Ethanol, fibrous material, and protein production of the studied biorefining process in Costa Rica.
Table 3. Ethanol, fibrous material, and protein production of the studied biorefining process in Costa Rica.
ParameterValue
Pineapple plantation (hectare)44,500
Leaf residue production (wet metric ton/year) a5,562,500
Total ethanol production (metric ton/year)92,708
Dry yeast biomass (metric ton/year)64,859
Potential energy generation (GJ/year) b9,892,019
Electricity generation (GJ/year) c2,924,872
Net energy generation (GJ/year) d1,066,523
a The pineapple leaf productivity is 125 wet metric tons/hectare/year. b The power generation (electricity and heat) is based on the total energy generation of the combustion of dry pulp. c The electricity generation is calculated using the efficiencies to convert the potential energy from dry pulp into electricity (84.48% and 35% for boiler and turbine-generator efficiencies, respectively) [27]. d The net energy generation (electricity and heat) is calculated using the energy generated from the biorefining (without considering the energy content of product ethanol) to subtract the energy used by the biorefining.
Table 4. Economic performance of a biorefinery with a capacity of 50,000 metric tons ethanol per year from pineapple leaves in Costa Rica.
Table 4. Economic performance of a biorefinery with a capacity of 50,000 metric tons ethanol per year from pineapple leaves in Costa Rica.
Capital Expenditure (CapEx)Unit Cost (USD)UnitCost (USD)Reference
Juice extraction a50,00021,000,000-
Ethanol fermentation b7,800,74317,800,743 [16]
Ethanol distillation b4,348,70114,348,701 [16]
Pulp drying c816,2001816,200 [18]
Yeast drying c1,293,38011,293,380 [18]
Boiler and generator d50,809,782150,809,782 [17]
Utilities e1,885,78211,885,782 [17]
Wastewater treatment plant f13,501,106113,501,106 [17]
Added direct and indirect cost (45% of total CapEx) g66,645,568166,645,568 [17]
Total CapEx 148101262
Operational Expenditure (OpEx)Unit CostUnitCost (USD)Reference
Diesel fuel for leaves collection and transportation h0.94 USD/kg for collection
21.53 USD/kg for transportation
11,601,343 kg/year for collection
1,584,402 kg/year for transportation
44,965,768
USD/year
[28]
Electricity for the juice extraction0.15 USD/kWh328,333,324 kWh/year49,250,197
USD/year
[29]
Electricity for the fermentation0.15 USD/kWh35,593,107 kWh/year5,338,966
USD/year
[29]
Electricity for the distillation0.15 USD/kWh5,050,167 kWh/year757,525
USD/year
[29]
Electricity for the pulp drying0.15 USD/kWh3,990,419 kWh/year598,563
USD/year
[29]
Electricity for the yeast drying0.15 USD/kWh7,216,700 kWh/year1,082,505
USD/year
[29]
Electricity for the wastewater treatment0.15 USD/kWh7,036,140 kg/year1,055,421
USD/year
[29]
Maintenance i--1,629,114
USD/year
-
Labor CostUnit Cost (USD)UnitCost (USD)Reference
Plant manager50,000/employee /year1 employee50,000
/year
[30]
Plant engineer40,000/employee /year2 employees80,000
/year
[30]
Maintenance supervisor30,000/employee /year1 employee30,000
/year
[30]
Maintenance technician25,000/employee /year8 employees200,000
/year
[30]
Lab manager30,000/employee /year1 employee30,000
/year
[30]
Lab technician20,000/employee /year3 employees60,000
/year
[30]
Shift supervisor20,000/employee /year4 employees80,000
/year
[30]
Shift operator15,000/employee /year16 employees240,000
/year
[30]
Yard employee10,000/employee /year2 employees20,000
/year
[30]
Clerk and secretary15,000/employee /year2 employees30,000
/year
[30]
Labor burden j 738,000
/year
Total labor cost 1,558,000
/year
Total OpEX 106,236,059
/year
RevenueUnit CostUnitCost (USD)Reference
Ethanol1.11 USD/kg50,000,000 kg/year55,500,000
/year
Current price
Dry yeast0.5 USD/kg35,000,000 kg/year17,500,000
/year
Current price
Electricity for national grid k0.15 USD/kWh438,183,086 kWh/year65,727,463
/year
Current price
Total revenue 138,727,463
/year
Net revenuel 32,491,404
/year
Payback time (years) m 4.72
a The juice extraction unit is based on a unit with a capacity of 5000 metric tons/day. The costs of individual units were obtained from a vendor. b The number was linearly scaled using the ethanol production from the reference. c The cost of the triple-pass rotary dryer is calculated based on the capital cost of 22 USD/kg water removed/hr. d The number was linearly scaled using the steam demand from the reference. e Utilities include equipment for water cooling/heating, electricity converter and transportation, steam delivery, etc. The number was linearly scaled using the ethanol production from the reference. f Wastewater treatment cost was linearly scaled using the ethanol production from the reference. g Added direct costs include warehouse, site development, and additional piping. Indirect costs include field expenses, home office and construction, proratable costs, and other costs. h The collection cost of 0.94 USD/kg diesel is for the fuel only. The transportation cost of 21.53 USD/kg diesel includes fuel, truck rental, and labor cost. i The maintenance cost is set at 2% of total equipment cost without considering added direct and indirect costs. j The labor burden is set at 90% of the total salary. k Electricity cost is calculated considering the conversion efficiency from burning dry pulp. l The net revenue—total revenue–total OpEx. m The payback time is a discounted payback time.
Table 5. Sensitivity analysis of key CapEx, OpEx, and revenue items on the discounted payback period of the biorefinery a,b.
Table 5. Sensitivity analysis of key CapEx, OpEx, and revenue items on the discounted payback period of the biorefinery a,b.
ItemBase ValueSensitivity RangeChange on Dynamic Payback Period
CapEx of the boiler/generatorUSD 5,080,9782USD 38,107,337–63,512,22816.5%–16.5%
CapEx of the wastewater treatmentUSD 13,501,106USD 10,125,829–16,876,3824.4%–4.4%
OpEx of the collection and transportation44,965,768 USD/yearUSD 33,724,326–56,207,21026.1%–52.3%
OpEx of the juice extraction49,250,197 USD/yearUSD 36,937,648–61,562,74628%–60.4%
a All values are adjusted by ± 25% of their base values. b The base payback period is 4.72 years.
Table 6. Life cycle inventory of the biorefinery and on-site burning.
Table 6. Life cycle inventory of the biorefinery and on-site burning.
ProcessItemValueUnitReference
Raw material inventoryPineapple leaves (wet amount)3,000,000Metric ton/year-
Total solids (TS) of pineapple leaves13.8%-
On-site burning (Control)Amount of pineapple leaves burned80% of TS [35]
CH4 emission factor1.6kg CH4/metric ton dry pineapple leaves burned [36]
N2O emission factor0.21kg N2O/metric ton dry pineapple leaves burned [36]
Particulate matter (PM) factor11.5kg/metric ton dry pineapple leaves burned [37]
SO2 emission factor0.21kg SO2/metric ton dry pineapple leaves burned [37]
NOx emission factor2.6kg NOx/metric ton dry pineapple leaves burned [37]
BiorefineryEnergy consumption of the process575,000,000MJ/year
CO2 emission factor from energy consumption of the process0.117kg CO2/MJ energy consumed [38]
Net ethanol production27,500Metric ton ethanol/year-
Energy content of ethanol a26.7MJ/kg-
Reduction factor of CO2 emission from replacing gasoline fuel0.067kg CO2/MJ fuel consumed [38]
a The low heating value of ethanol.
Table 7. Comparison of the life cycle impact assessment between the biorefinery (50,000 metric tons ethanol/year) and control on-site burning.
Table 7. Comparison of the life cycle impact assessment between the biorefinery (50,000 metric tons ethanol/year) and control on-site burning.
ParameterBiorefineryOn-Site Burning
Particulate matter potential (metric ton/year)05951
Global warming potential (metric ton CO2-e/year)−71,62044,339
Air acidification (metric ton SO2-e/year)0923
Smog potential (metric ton O3-e/year)028,167
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Liao, C.Y.; Guan, Y.J.; Bustamante-Román, M. Techno-Economic Analysis and Life Cycle Assessment of Pineapple Leaves Utilization in Costa Rica. Energies 2022, 15, 5784. https://doi.org/10.3390/en15165784

AMA Style

Liao CY, Guan YJ, Bustamante-Román M. Techno-Economic Analysis and Life Cycle Assessment of Pineapple Leaves Utilization in Costa Rica. Energies. 2022; 15(16):5784. https://doi.org/10.3390/en15165784

Chicago/Turabian Style

Liao, Clara Yuqi, Ysabel Jingyi Guan, and Mauricio Bustamante-Román. 2022. "Techno-Economic Analysis and Life Cycle Assessment of Pineapple Leaves Utilization in Costa Rica" Energies 15, no. 16: 5784. https://doi.org/10.3390/en15165784

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop