This study presents a comparative analysis of various configurations for sustainable olefins production via chemical recycling of plastic/biomass wastes, integrating CO2 capture, storage and management technologies. The co-gasification, methanol synthesis and methanol-to-olefins process models were developed on the Aspen Plus® software. Optimization of processing conditions is achieved through the OSMOSE Lua platform, for minimizing the total cost of operation while accounting for seasonal variability in the electricity prices. CO2 valorization processes have been shown to increase carbon efficiency from 55% up to 97% compared to steam naphtha cracking, making chemical recycling of plastics an appealing alternative. In addition, direct CO2 emissions can be fully eliminated, resulting in up to 70% lower net CO2 emissions even when fossil-based plastic waste is used as feedstock. Seasonal CO2 storage can extend the economic benefits by acting as a buffer against high electricity costs an... [more]

This work aims to develop an energy storage system that allows fluctuating energy inputs (i.e. from process sections driven by renewable sources) to power two process units that are operated continuously at different temperatures. The system consists of two vessels storing diathermal mediums: one for the hotter- and the other for the colder-energy fluxes. The investigated solutions include sensible-heat-, latent-heat-, and thermochemical-TES (thermal energy storage). Organic Rankine cycles (ORCs) with lithium-ion batteries and thermoelectric generators were also assessed. Indeed, all these technologies allow the exploitation of low-temperature thermal energy to supply the high-temperature unit during periods of energy scarcity. Both vessels aim for total self-sufficiency; however, the option to rely on external utilities has been included to meet the energy demand of both units when sufficient process-side power is unavailable. Two energy profiles were investigated to assess the propos... [more]

Traditional steel processes are energy-intensive and rely heavily on fossil fuels, contributing to significant greenhouse gas emissions. By adopting electrification technologies, such as electric boilers and compressors, particularly when powered by renewable energy, steel plants can reduce their carbon footprint, enhance process flexibility, and lower long-term operational costs. This transition also aligns with increasing regulatory pressures and market demand for greener practices, positioning companies for a more competitive and sustainable future. This work investigates the potential of replacing conventional steam crackers in a steel plant that relies on the use of fossil fuels, with electrically driven heating systems powered by renewable energy sources. The overall aim was to significantly lower greenhouse gas emissions by integrating electric furnaces and heat pumps into the steel production process. This study evaluates the potential carbon savings from the integration of sol... [more]

Multi-component batch distillation, wherein multi-component mixtures are separated using a single column, is a crucial separation technique in the chemical industry. Traditionally, the components are separated in the descending order of volatility (direct sequence). Similar to continuous distillation, a specific separation sequence can optimize batch distillation. This work aims to generate such optimal sequence for a batch distillation in a computationally efficient manner. Specifically, the proposed approach extends the marginal vapor rate method, which is used for sequencing continuous distillation to multi-cut batch separation. The approach addresses challenges arising due to dynamic nature of batch distillation. The proposed methodology is validated using simulation case studies.

This study investigates the development of a probabilistic design space (DS) for a tableting process, focusing on the uncertainty in critical model parameters. A an empirical model is used to assess the impact of critical process parameters (CPPs), including lubrication extent and porosity, on tablet tensile strength (CQA). By incorporating Monte Carlo and Bayesian techniques, the uncertainty of five model parameters is propagated, allowing the estimation of feasibility probabilities for achieving CQAs with a reliability greater than 0.95. The resulting probabilistic DS provides manufacturers with a tool to assess the likelihood of meeting CQAs under varying production conditions. The findings indicate that specific combinations of lubrication rate and porosity define a robust DS within the acceptable operating region, ensuring consistent tableting performance even in the presence of uncertainties. This approach emphasizes the importance of probabilistic DS in optimizing manufacturing... [more]

In this contribution, a thermodynamic model-based approach for the optimal design of a solid-state hydrogen storage and release system utilizing the reversible iron oxide/iron thermochemical redox mechanism is presented. Existing storage processes using this mechanism face significant limitations, including low hydrogen conversion, high energy input requirements, limited storage density, and slow charging/discharging kinetics. To address these challenges, a custom thermodynamic model using NIST thermochemistry data is developed, enabling an in-depth analysis of redox reaction equilibria under different conditions. Unlike previous studies, this approach integrates a multi-objective optimization framework that explicitly balances competing objectives: maximizing hydrogen yield while minimizing thermal energy demand. By systematically identifying optimal trade-offs, the study provides new insights into improving process efficiency and reactor design for thermochemical hydrogen storage. Th... [more]

Biomass gasification is a promising technology for sustainable energy production. To date, extensive research has been conducted on biomass gasification, particularly focusing on the reaction models of the process. However, existing models are too complex to apply to the control system or to optimize the process operating conditions effectively, limiting their practical use for industrial applications. To address this, a simple reaction model for biomass gasification was developed and validated. A steady state simulation of the biomass gasification process is conducted to analyze gasifier behavior and provide insights into reaction dynamic. The findings in this study align well with existing literature, confirming the reliability of the approach. This simulation serves as a foundation for further study in process control and optimization. Future work will include experimental validation to enhance model accuracy and applicability.

As greenhouse gas emissions continue to increase worldwide, the growing energy demand must be met using low-carbon technologies. Renewable energy and carbon capture and storage are the two important technologies that can mitigate CO2 emissions. The two technologies have been primarily developed independently. However, their hybridization can offer complementary benefits and lower the costs of greenhouse gas abatement. Accordingly, in this article, we develop a novel carbon-neutral process that combines concentrated solar power (CSP) and fuel-based combustor with redox-based thermochemical energy storage (TCES) materials. The TCES materials are used for energy storage and as a source of oxygen (O2) for combusting fuel. We optimize the process’ economic performance considering variability in solar irradiance by developing a two-stage stochastic programming model. We illustrate that compared to the CSP-TCES process employing the Mn2O3/Mn3O4 TCES system, the proposed hybrid process has a 2... [more]

Electrified steam methane reforming has emerged as a promising technology for electrifying the hydrogen production process industries. Unlike conventional fossil fuel-based steam methane reforming, the electrified steam methane reforming process relies exclusively on electrical heating, eliminating the need for fossil fuel combustion. Beyond that, however, significant amounts of electricity required for the electrified process should be imported from the renewable energy-based system rather than fossil fuel-based grid electricity to have an environmental advantage over the conventional process. This study suggests a framework for integrating renewable energy systems into the electrified process for decarbonized hydrogen production. Considering the variability of renewable energy, wind and solar power are supplemented by battery storage, to facilitate a stable electricity supply to the electrified hydrogen production process. A Mixed-Integer Linear Programming (MILP) model is developed... [more]

Hydrogen (H2), as the promising alternative to fossil fuel-based energy carriers, faces the critical challenge of diversifying its sources and lowering production costs. Biogas, produced from organic waste, offers a renewable and carbon-neutral option for H2 production, but its high CO2 content requires a pre-separation process of CO2 from CH4 or specialized catalysts for use in existing reforming processes. Chemical looping reforming (CLR), as an advanced H2 production process, uses an oxygen carrier (OC) as the oxidant, allowing raw biogas to be used directly in the reforming process. Recently, numerous studies on CLR design and analysis have demonstrated their growing economic feasibility. However, deploying the CLR process in the biogas treatment industry requires further research to analyze its technical, economic, and environmental performance under target capacities and H2 purity. This study proposes biogas-based CLR processes and analyzes the capability of the processes from te... [more]

L-lactic acid (L-LA), a key monomer in biodegradable plastics, is a sustainable alternative that can be derived from LCB. The L-LA production process typically involves various technologies such as fermentation, filtration, and distillation. In the L-LA production process, large amounts of buffers are used to maintain proper pH during fermentation, so conventional buffers (e.g., CaCO3) are often selected because of their low cost. However, these buffers cannot be recycled efficiently, and the potential for alternative buffers remains uncertain. In this work, we aim to develop and evaluate novel processes for sustainable L-LA production using the alternative buffer (i.e., KOH). The processes involve a series of different unit operations such as pretreatment, fermentation, extraction, and electrolysis. An efficient buffer regeneration process using membrane electrolysis is implemented to recycle the buffer with minimal energy input. Then, we evaluated the viability of the proposed proces... [more]

The transition to a circular economy (CE) requires agents in circular supply chain (SC) networks to take a variety of different initiatives, many of which are dynamic in nature. We use a system dynamics (SD)-based approach to develop a generic framework for dynamic modeling of CE networks and propose a prototypical circular SC network by combining dynamic models for five actors: a manufacturer, consumer, material recovery facility (MRF), recycling facility, and the Earth. We apply this framework to the supply chain for Polyethylene Terephthalate (PET) plastic packaging by considering different scenarios over a 65-year time horizon in the US. We include both "slow-down-the-loop" initiatives (i.e., those that extend product use time through demand reduction or reuse) and "close-the-loop" initiatives (i.e., those that reintroduce product to the supply chain through recycling) by the consumer, as well as sorting and recycling capacity expansion. We find that, given the current recycling in... [more]

A simple mathematical model of the co-precipitation of Ni-Mn-Co hydroxides is developed and applied to investigate the effect of pH, initial concentration of ammonia in the solution, concentration of the ammonia feed, nucleation rate constant and exponent, growth rate constant and growth exponent over the model output. The model is shown to produce a correct representation of the precipitation variables, and the general trends obtained for different sets of parameters are found in agreement with results presented elsewhere. A sensitivity analysis is carried out and the sensitivity indices are calculated. It is found that pH, initial concentration of ammonia and growth rate constant are the input parameters with the most relevant effect over the model input.

As anthropogenic CO2 emissions continue to drive global warming, innovative approaches to repurpose CO2 into valuable products emerge as pivotal solutions to mitigate its environmental impact. CO2 utilization encompasses a range of technologies, including its conversion into fuels, chemicals, and materials, leveraging CO2 as a resource rather than treating it solely as a waste. This shift not only reduces greenhouse gas emissions but also supports the circular economy by integrating industrial processes with carbon capture and storage technologies. Specifically, in the Waste-to-Energy (WtE) context, sodium bicarbonate production can be an attractive solution, considering that it is required in the plant for SOx and acidic gases abatement. In this work, the carbon dioxide utilization to give sodium bicarbonate in a WtE context is analyzed. With reference to an existing waste-to-energy plant in Italy, the potential of this CO2 utilization method is highlighted by means of process simulat... [more]

Trichlorosilane (TCS) is a platform chemical used in the manufacture of silicon metals, silicones, and functional silanes. Despite this, very little information is available on the environmental impact (EI) associated with its manufacture. This work addresses this gap by developing estimates for the EI of reagent grade TCS (RG-TCS) based on a combination of process modelling & optimisation and life cycle assessment (LCA). Two production methods are considered: 1) direct chlorination (DC) producing RG-TCS as a main product, and 2) the Siemens process (SP) producing RG-TCS as a co-product. Results of a bi-objective process optimization suggest that the DC approach provides consistently better pareto-optimal (PO) trade-offs between the global warming potential (GWP) of RG-TCS and process profit; predicted GWPs are 3.2 to 3.3 kgCO2-eq/kg for DC-derived RG-TCS and 3.8 to 4.9 kgCO2-eq/kg for SP-derived PO designs. This suggests that processing history is important when considering the EI of... [more]

This work presents a robust flowsheet design for the recovery and purification of waste solvent streams containing ethyl acetate (EtAc), methanol (MeOH), and water. Separation of this mixture is challenging due to the presence of two azeotropes: a homogeneous EtAc-MeOH azeotrope and a heterogeneous EtAc-water azeotrope. These azeotropes create a distillation boundary that divides the ternary composition space into two distinct regions, making separation via conventional distillation difficult. Additionally, the wide variability in waste solvent compositions requires a versatile design, as flowsheets optimized for dilute mixtures may not be feasible for concentrated ones. The key to this design is using a liquid-liquid extractor (LLX) with recycled water as the solvent, ensuring the mixture remains within the liquid-liquid equilibrium (LLE) split region, which facilitates spontaneous separation across the distillation boundary and promotes energy-efficient separation. The raffinate comp... [more]

This study investigates the design of a two-column distillation (TCD) process to separate a dilute ternary Ethyl Acetate (EtAc)-Methanol (MeOH)-water waste solvent into nearly pure components. The separation is complicated by the presence of a homogeneous EtAc-MeOH azeotrope and a heterogeneous EtAc-water azeotrope, creating a distillation boundary that divides the ternary composition space into two distinct regions. To address this, the proposed flowsheet incorporates liquid-liquid phase separation to cross the distillation boundary, enabling feasible separation. Additionally, the pressure sensitivity of the distillation boundary is exploited to reduce the recycle rate, enhancing energy efficiency. The basic TCD flowsheet consists of a decanter, a high-pressure simple column, and a low-pressure divided-wall column (DWC). Heat integration (HI) is achieved using external process-to-process heat exchangers and vapor recompression (VR)-driven reboilers. The resulting energy-efficient HIVR... [more]

This study presents a gate-to-gate Life Cycle Assessment (LCA) evaluating the sustainability and environmental impacts of utilising CO2 for Enhanced Oil Recovery (EOR) in Dukhan Field. The assessment employs a detailed model that encompasses CO2 capturing, transportation, injection, and oil production processes. Utilising Gabi software, the study assesses CO2 emissions across different stages of the EOR process and evaluates the environmental efficiency using two functional units: '1 kg of CO2 captured' and '1 kg of oil produced'. Results indicate that Post-Combustion Capture (PCC) contributes the highest emissions, accounting for 76% of the total Global Warming Potential (GWP), while transportation pipelines and separators contribute only 2% and 4%, respectively. By Year 21, emissions drop by over 98%, with a corresponding GWP reduction from 4.73 billion kgCO2e in Year 1 to 94.97 million kgCO2e. Emission rates for CO2 capture and oil production also decrease significantly, reaching 0.... [more]

The growing concern over climate change and rising carbon dioxide (CO2) emissions have spurred the development of strategies to upcycle greenhouse gases. One promising solution is the synthesis of green methanol via catalytic hydrogenation of captured CO2 using renewable hydrogen (H2). This provides a versatile chemical feedstock for fuels and industrial processes while reducing CO2 levels. Recent advancements in CO2 capture technologies achieve purities ranging from 83% to 98% (v/v), enabling a sustainable integration with green hydrogen for methanol production. While research has largely focused on CO2 purities above 96%, such models overlook the variability and lower purities typical of industrial carbon capture streams. Addressing this gap, this study examines the economic impacts of CO2 purity on methanol synthesis. Using Aspen Hysys V14, the hydrogenation process is simulated to assess the effects of varying CO2 purities on operational costs, yield, and profitability, providing a... [more]

This study explores an energy transition strategy that leverages reversible solid oxide cells (rSOC), power-to-gas (PtG) conversion, and CO2 management to enhance the efficiency and sustainability of secondary aluminum production. A comparative analysis between conventional and integrated energy scenarios highlights the benefits of multi-technology integration. The results indicate that the integrated system increases total energy demand by 27% due to additional energy conversion steps, but eliminates natural gas consumption, reducing dependency on fossil fuels. Additionally, net CO2 emissions are reduced more than fivefold, demonstrating the potential of carbon capture and utilization strategies. The seasonal storage of synthetic natural gas (SNG) and biogenic CO2 further enhances system flexibility, allowing excess renewable electricity to be converted into storable fuels for winter use. Despite higher capital expenditures, the operational costs of the integrated system are 11% lower... [more]

Emerging technologies require sophisticated design and optimization due to their rapid advancement and potential to alter material flows and life cycles. However, their future development remains uncertain due to sociotechnical factors such as regulations, infrastructure, and market dynamics. Multiple technologies are often considered simultaneously, but their interactions and synergies are not systematically evaluated. This study addresses pre-emptive life cycle design in social challenges by integrating emerging technologies into superstructures, which help visualize alternative candidates for design problems. Case studies on battery chemistry, plastics, and regional resource circulation demonstrate this approach. For battery technology, nickel-manganese-cobalt lithium batteries have dominated over lithium iron phosphate alternatives. Superstructures were developed to assess recycling technologies and were refined through communication with managers of Japanese national battery proje... [more]

This work investigated synergies for improved energy efficiency between integrated first- (1G) and second-generation (2G) sugarcane ethanol distillation, an energy-intensive unit operation, especially for stand-alone 2G ethanol. For this investigation, integrated and separated 1G2G distillation simulations were conducted using Aspen Plus v.10 assuming a dilute 2G fermentation beer with titer varying from 5 to 40 g/L. The results were then assessed in heating energy demand savings for distillation, and it was measured the potential of saved bagasse (boiler fuel) for valorization in either electricity or 2G ethanol. A life cycle assessment was also performed for a consequential approach to carbon emission reductions from energy savings. As our main result, distillation integration can maintain the heat demand of a stand-alone 1G mill, regardless of the 2G ethanol beer titer. This means energy savings between 9 and 15% in total ethanol heat demand, and between 46 and 92% in 2G ethanol hea... [more]

Acetic acid is an important bulk chemical and one of the major downstream products of methanol. However, it has received less attention from an environmental sustainability perspective. Here, we evaluate the absolute sustainability of several acetic acid synthesis routes, considering both fossil and renewable feedstocks. More specifically, we studied the business-as-usual (BAU) methanol carbonylation and the novel, low technology readiness level (TRL) methane carboxylation and semi-artificial photosynthesis routes. Using process simulation and life cycle assessment (LCA), our results reveal that the alternative routes have the potential to outperform the fossil BAU in at least 14 out of the 16 evaluated impact categories. However, despite the overall improvements, their performance in SDGs 3, 6, 13, 14 and 15 remains poor in any of the studied scenarios, which could potentially be addressed by hybridizing fossil and renewable feedstocks. All in all, our analysis underscores the importa... [more]

The pharmaceutical and specialty chemical industries are challenged with the requirement of faster time-to-process to meet market demands. Here, Modular Plants made up of predesigned process equipment assemblies (PEAs) are advantageous. Moreover, equipment-based Digital Twins of these modules can further reduce the time-to-process when combined with methods such as Quality by Design (QbD) and model-based design of experiments (MBDoE) to reduce uncertainty. This paper presents a lab scale-based workflow using an equipment-based Digital Twin, which applies QbD and MbDoE methods to identify the Design Space in the lab scale which can be transferred to production scale equipment as part of a Digital Twin based workflow for scale-up in Modular Plants.

Triethylene glycol (TEG) or mono-ethylene glycol (MEG) absorption are the commercial technologies for natural gas dehydration processes. Nevertheless, the necessity of regenerating solvents under high temperatures results in environmental footprint and complex operation. Membrane with advantages in small footprint and high feasibility operation in hostile conditions is considered as promising technology for natural gas dehydration processes. In this work, system scale design and mesoscale modelling are synchronously adopted to optimize natural dehydration process design. Aspen HYSYS with ChemBrane extension is used for natural gas dehydration process. Taking pressure ration, membrane area and sweep gas flowrate as decision variables for minimizing specific process cost is optimized through NSGA-II algorithms. The minimum specific cost of < 3.06×10-2 $/m3 natural gas is estimated to achieve the separation requirement of <100 ppm. Then, the module length, and membrane thickness of... [more]