# Supply Chain Design for Waste Vaporization Through High-Energy-Density Pellet Production in Chile
###### Abstract  
This study presents the development and application of a mathematical optimization model to improve decision-making in the supply chain for high-energy-density pellet (HEDP) production and commercialization. Focused on the Metropolitan Region of Chile, the research involved a detailed analysis of key supply chain components, including identifying landfills and controlled dumps, waste volume assessments, plant location analysis, technology evaluation, and market potential exploration. The model revealed that the available raw material in the region was sufficient to meet 100% of HEDP demand, with a surplus of 2,161,952 tons remaining after satisfying maximum demand. An optimization analysis of potential plant locations identified Santa Marta as the optimal choice, resulting in annual cost savings of USD 100,000 compared to other sites. This work underscores the role of mathematical optimization in enhancing supply chain efficiency for biomass-based energy products, offering valuable insights for strategic decision-making in similar contexts. hydrothermal carbonization; supply chain optimization; high-energy-density pellets; waste management; mathematical optimization +
Footnote †: journal: applied sciences  
various factors, including inadequate public awareness, insufficient recycling facilities, and logistical challenges in waste collection and sorting [8]. Chile's rapid urbanization and population growth have increased waste generation, adding pressure to existing waste management systems [9]. Although Chile's legislative framework is progressive, achieving the intended outcomes requires more robust enforcement and support mechanisms [10; 11]. This situation underscores the need for enhanced waste management strategies, improved recycling infrastructure, and stronger collaboration between government bodies, private sector stakeholders, and the public [12]. Addressing these challenges can help Chile improve recycling rates, reduce reliance on landfills, and move towards a more sustainable and circular economy. In this context, innovative solutions, such as developing advanced recycling technologies and integrating waste-to-energy processes, could further contribute to mitigating the environmental impact of waste and enhancing resource recovery [13]. An innovative solution to this issue is the production of high-energy-density hydrophobic pellets (HEDPs) through hydrothermal carbonization (HTC) of residual biomass [14]. HTC offers several key advantages over traditional biomass conversion methods. These include higher energy efficiency, the ability to process wet biomass without prior drying, and the production of a more homogeneous and stable product with superior combustion properties [15; 16]. Additionally, the HTC process can be directly applied to biomass with high moisture content (often challenging to process using conventional methods), converting materials like microalgae, sewage sludge, and food waste into a lignite-like solid product known as hydrochar, which has significant potential for energy recovery [17]. For better handling, transportation, and fuel storage, densification processes have been applied to hydrochar fines using solid fuel [18]. The peltetization process results in high-density pellets (briquettes) characterized by increased energy, bulk density, and mechanical strength [18]. However, significant challenges arise from the high costs of transporting raw materials and finished products and the initial expenses associated with establishing production plants [19; 20]. Optimizing the supply chain with decision-support tools is crucial for facilitating hydrothermal carbonization technology's development and future industrialization. These tools would assist in making informed decisions regarding production capacities and raw material requirements based on market demands [1]. Specifically, optimizing industrial processes in Latin America can play a pivotal role in leveraging regional resources and capabilities to enhance efficiency and sustainability [21].