Techno-economic assessment of pilot-scale nanocellulose production from pineapple peel residues in Costa Rica

Technical Summary: Techno-economic Assessment of Pilot-scale Nanocellulose Production from Pineapple Peel Residues in Costa Rica

Problem Statement
Costa Rica generates approximately 640 kilotons of lignocellulosic waste annually, primarily from its pineapple industry (stubble, crowns, and peels). While pineapple peels offer an attractive feedstock due to their ease of handling and adequate cellulose content, they currently pose significant logistical and environmental management challenges. Although nanocellulose is a high-value, renewable biomaterial with applications in food, cosmetics, pharmaceuticals, and packaging, the techno-economic viability of converting Costa Rican pineapple peel residues into nanocellulose at a pilot scale has not been rigorously assessed. Furthermore, traditional production methods often rely on chlorinated bleaching agents, which present environmental management issues at industrial scales.

Methodology
This study presents a desk-based techno-economic assessment of a pilot-scale facility designed to produce 48,000 kg/year of nanocellulose (primarily cellulose nanofibers, CNF) from approximately 140,000 kg/year of pineapple peel. The assessment integrates market analysis, process design, mass and energy balances, and financial modeling.

• Process Design: The proposed route utilizes a chlorine-free process comprising:

  1. Milling: Mechanical size reduction of pineapple peels.
  2. Alkaline Pretreatment: Using sodium hydroxide to remove lignin, hemicellulose, and esters.
  3. Bleaching: Using hydrogen peroxide (an alternative to sodium hypochlorite) to further purify the cellulosic fraction.
  4. Fibrillation: High-pressure homogenization at 60 MPa with 10 cycles at a solid concentration of 30 g/L.
  5. Drying: Spray drying to produce dry nanocellulose powder.
     The mass balance assumes a 34% recovery yield of purified cellulosic material based on literature data for pineapple peels and related lignocellulosics.

• Financial Modeling:

  • Investment: Capital costs were estimated using the factorial method (Smith), distinguishing between Fixed Capital Investment (FCI), Working Capital (WC), and Total Capital Investment (TCI). Land acquisition was modeled separately at a specific Costa Rican value of $1.5 million.
  • Operating Costs: The Cost of Manufacturing (COM) was calculated using the methodology of Turton et al., accounting for raw materials, labor, utilities, and waste treatment.
  • Context: The plant is modeled within a Free Trade Zone (Muelle Free Zone), granting tax exemptions on imports and profits for the first 10 years.
  • Financial Indicators: A 10-year discounted cash flow analysis was performed using a 12.5% discount rate to determine Net Present Value (NPV), Internal Rate of Return (IRR), Return on Investment (ROI), and Payback Period.

Key Results

• Market Analysis: The study identifies the Netherlands and the broader European market as priority targets, citing existing interest from Dutch companies (e.g., Avantium, Smurfit Kappa) in Costa Rican nanocellulose. The primary target sectors are paper, cardboard, and packaging, followed by biomedical and academic research. Cellulose nanofibers (CNF) are identified as the primary product, with cellulose nanocrystals (CNC) as a potential secondary product pending morphological validation.
• Capital and Operational Costs:
  • Total Capital Investment (TCI): $669,200 USD.
  • Total Initial Investment (including land): $2.2 million USD.
  • Annual Cost of Manufacturing (COM): $2,265,500 USD.
• Financial Performance: At an average selling price of $75/kg, the project demonstrates strong economic potential:
  • Net Present Value (NPV): $6.7 million USD.
  • Internal Rate of Return (IRR): 199.4%.
  • Return on Investment (ROI): 61.5%.
  • Payback Period: 19.5 months.

Significance and Claims
The paper claims that the production of nanocellulose from Costa Rican pineapple peel residues is both technically feasible and economically promising under the modeled assumptions. The study highlights that a chlorine-free process using hydrogen peroxide and high-pressure homogenization is viable for pilot-scale production.

However, the authors maintain a modest stance regarding the readiness of the project for immediate commercialization. They assert that the case is strongest for a cellulose nanofibers-led product platform. Before submission for full-scale implementation, the authors state that the project must be strengthened by:

1. Validating the specific product morphology.
2. Confirming actual energy demand.
3. Characterizing wastewater streams.
4. Securing firm market off-take conditions.

The work positions this pilot-scale assessment as a critical step toward valorizing agricultural waste within a circular bioeconomy, transforming low-value waste streams into high-value advanced materials while addressing environmental management challenges in Costa Rica's pineapple sector.