(249e) Netz-CMI: A User-Friendly Tool for Achieving Net-Zero Transition for the Chemical and Material Industries

In a world increasingly aware of environmental impacts and the urgent need to transition towards more sustainable practices, businesses are under growing pressure not just to perform economically but to do so in a way that is environmentally responsible and sustainable. We have developed a tool for achieving the transition to a Net-Zero Chemical and Material Industry (NetZ-CMI), which addresses this need by offering a comprehensive, user-friendly platform that allows companies to evaluate the environmental footprint and financial performance of their products comprehensively. By enabling stakeholders to easily compare different supply chain scenarios, NetZ-CMI facilitates informed decision-making aimed at enhancing sustainability while optimizing economic outcomes. Companies can leverage NetZ-CMI to navigate the complex trade-offs between environmental sustainability, circularity, and profitability, helping to align their operations with global sustainability goals. This not only aids individual businesses in achieving their sustainability and economic objectives but also contributes to broader societal efforts to mitigate environmental degradation and promote a sustainable circular economy. NetZ-CMI embodies a step forward in making sustainable business practices accessible, actionable, and advantageous for a wide range of actors in the material and chemical industries, marking a pivotal point in how companies approach the integration of sustainability into their core strategies.

The initial version of NetZ-CMI is tailored for the multi-layer plastic films supply chain, with a specific focus on a case study involving multi-layer films utilized in the Sheet Molding Compound process (SMC films). Unlike our previous efforts that delve into the technical and sustainability outcomes of various end-of-life scenarios, our emphasis in this contribution lies in the development of the tool itself and its capacity to evaluate and design a sustainable and profitable circular economy for multi-layer plastic films. The recovery of SMC films at their end of life poses challenges due to film contamination and their complex chemical structure, rendering conventional mechanical recycling impractical. As a result, emerging low-emission technologies are required to facilitate the transition of multi-layer films towards a circular and sustainable economy. NetZ-CMI serves as a valuable tool in identifying the obstacles to achieving this objective and pinpointing the optimal end-of-life technological solutions that align with circularity, economic, and sustainability goals for multi-layer plastic films.

Based on both experimental work and an extensive literature review, we have defined six end-of-life strategies for multi-layer plastic films including landfilling, incineration, solvent-based reuse, solvent-based recycle, downcycle, and pyrolysis. In the landfilling scenario, the multi-layer film is disposed of in a landfill after its use phase. This represents the business-as-usual approach and is currently the dominant waste management strategy for multi-layer films. An alternative to landfilling, especially prevalent in Europe, involves incinerating most plastic waste at the end of its life. The solvent-based reuse scenario utilizes a mechanical and solvent cleaning (MASC) technique to clean the film, allowing for its reuse for the same purpose.

The solvent-based recycle scenario involves using a solvent targeted recovery and precipitation (STRAP) technique to extract different layers of polymers from the multi-layer film and subsequently recycles the resin to produce new multi-layer film. In the downcycle scenario, the film is subjected to pelletization and injection molding processes to create molded products from the film waste pellets. This represents an open-loop recycling approach. The pyrolysis scenario considers a chemical recycling or energy recovery approach. The multi-layer film is processed in a pyrolysis reactor to produce pyrolysis oil. This oil can be recycled to make base monomers or used as a fuel source.

NetZ-CMI comprises two main components, namely Analysis and Design. In the Analysis part, users can compare various end of life scenarios for treating multi-layer plastic films with a focus on product recovery. Users have the flexibility to select any combination of end of life scenarios (e.g., 50% landfilling, 50% solvent-based reuse) and conduct scenario analysis to assess sustainability, circularity, and economic performance. They can then compare the results with the base case (BAU) scenario. Users also have access to different options for assessment, such as choosing the type of impact assessment method, life cycle inventory database, circularity and economic indicators, depending on their metric of interest and stakeholder goals. Once scenarios and assumptions are selected, users can run the simulation to obtain sustainability analysis results. These results include total environmental impacts (e.g., global warming potential, acidification, etc.), circularity metrics, and cost (production and annual costs). Additionally, users can access detailed information such as top supply chain and process contributors to environmental impacts (bottleneck analysis) and flow Sankey diagrams illustrating plastic, material, and energy flows. Detailed economic results, including supply chain and process breakdown costs, are also provided.

In the Design part of NetZ-CMI, a generic multi-objective optimization framework is employed to identify the optimal solution for end of life recovery of multi-layer films, considering environmental impacts, circularity, and cost. By optimizing the supply chain, NetZ-CMI generates optimized solutions and illustrates the trade-offs between these objectives. Users can evaluate and select the desired solution among the optimized solutions and compare it with the base case to identify opportunities and improvements. Through optimization, NetZ-CMI determined that the solvent-based recycle scenario, utilizing the STRAP process for film recovery, offers the best solution in terms of minimizing global warming impact (GWP). This is attributed to the STRAP process's ability to recover resins with high purity and yield, as well as achieving a high solvent recovery rate through distillation, thereby improving process economics and reducing life cycle environmental impacts associated with solvent use. However, it's important to note that the minimum-cost solution differs from the minimum GWP solution. Landfilling emerges as the minimum-cost solution due to factors such as low tipping fees for landfilling, the absence of carbon taxes, and the high costs associated with alternative end of life treatment processes. This suggests that to minimize the trade-off between GWP and cost, measures such as banning landfilling or implementing higher landfill tipping fees should be considered. Additionally, the implementation of a carbon tax could incentivize scenarios that result in minimum GWP.

While the initial version of NetZ-CMI was designed specifically for multi-layer plastic films, its generic framework allows for expansion to accommodate any product system within the material, chemical, and plastic industry. Currently, NetZ-CMI is undergoing development to map the entire material and chemical industry, aiming to provide roadmaps for achieving a net-zero carbon economy by 2050 that is both resilient and sustainable. This expansion underscores NetZ-CMI 's versatility and potential to address sustainability challenges across various industrial sectors.