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]

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]

By-product fuel gases from refinery operations are a major heat source in fossil refineries and their availability poses a challenge to the deployment of low-carbon heat sources. This study evaluates the valorization of refinery fuel gases (RFG) into low-carbon methanol via co-processing with residual biogenic gas streams from biomass thermochemical conversion. Results from techno-economic analysis indicate that up to 44 wt.% of biogenic blend is possible without the need for external hydrogen supply, while electricity and heat requirements per tonne of methanol change by -4 % and + 80% respectively. Nevertheless, at the 44 wt.% blend, the estimated methanol cost increases only by 2.4 % (0.43 EUR/kg), while the reduction in methanol carbon intensity is approximately 40 %. This highlights promising benefits that can contribute to the integration of bio-oils producing technologies within fossil refineries.

Biomass conversion to chemical derivatives and essential intermediates is regarded as a long-term strategy for the chemical sector. Among the numerous valuable chemicals obtained from biomass, 5-hydroxymethylfurfural (HMF) is considered an industrially relevant compound due to its capacity to be converted into a variety of value-added chemicals. Compared to conventional catalytic synthesis, bio-catalysis has emerged as a potential greener substitute for HMF conversion to value-added compounds. HMF conversion through bio-catalysis, although more sustainable, seldom leads to the production of a single derivative. Thus, the development of efficient purification and separation processes of several products are crucial to scalability. The downstream process for the novel enzymatic conversion of HMF to high value-added chemicals (i.e., 1-phenylethylamine, 2,5-bis(hydroxymethyl)furan, 1-phenylethylalcohol, and 5-(aminomethyl)-2-furanmethanol) was designed by means of rigorous simulations in A... [more]

Plastic recycling is prevalently mechanical, which is inefficient at removing contaminants and produces low-grade materials. Solvent-based polymer dissolution and precipitation is emerging as a low-energy alternative to mechanical recycling when tackling highly contaminated plastic waste streams. We present a computer-aided molecular and process design (CAMPD) formulation for the selection of optimal solvents and process temperatures for polymer recycling via a dissolution and precipitation process. A mixed-integer nonlinear programming (MINLP) model is proposed to minimize the energy requirement for the dissolution of commercial low-density polyethylene, a ubiquitous polymer in industrial and municipal plastic waste, while minimizing the solvent viscosity and toxicity through multiobjective optimization. We integrate the SAFT-??Mie group-contribution equation of state in the optimization framework to predict key thermodynamic properties and to ensure that the desired phase behaviour i... [more]

Acrylonitrile is a critical commodity chemical used to produce a variety of industrial polymers, such as carbon fibers, plastics, etc. Currently 90% of the global acrylonitrile production is based on propylene ammoxidation. However, there is no literature reporting the whole process holistically in detail, and which also looks into the energy utilization of the whole process including the reaction heat as well as the energy demands of the downstream separation. This original study provides a rigorous process design of the full process from a holistic viewpoint, covering 7 sections of acrylonitrile production (reaction, acid quenching, absorption-desorption, hydrogen cyanide recovery, acrolein recovery, acrylonitrile-acetonitrile-water separation, acetonitrile recovery sections). In order to further improve the energy efficiency, three energy integration strategies are proposed (1) Energy integrated downstream processing; (2) Systematic heat integration utilizing the heat of reaction; (... [more]

An intensified approach to ?-valerolactone (GVL) production is achieved using a reactive distillation column. Conventional methods require multiple units, leading to high energy consumption, costs, and limited scalability. The proposed technology integrates reaction and separation into a single unit, enhancing process efficiency for biomass-derived chemicals. A multiobjective optimization framework balances economic, environmental, and operational goals, reducing total annual cost (TAC) by 43% and environmental impact (EI99) by 45% compared to conventional processes. Additionally, energy consumption drops by 63%, while GVL production increases by 25%, highlighting the potential of reactive distillation for improved efficiency and sustainability.

In this research, a novel process is developed that utilizes low density polyethylene from plastic waste to produce ethylene. In this process, waste polyethylene is reacted in a microwave reactor to produce ethylene. A conceptual flowsheet based on this reactor is developed in the ASPEN Plus environment. Heat integration tools are utilized to reduce the hot and cold utilities used in this process. This novel design is compared with the conventional process of making ethylene from ethane via cracking. A technoeconomic analysis is conducted to demonstrate the economic feasibility of this process.

Process Systems Engineering (PSE) provides the advanced conceptual framework and software tools to formulate and optimise well-considered integrated solutions that could accelerate the sustainability transition within the industrial sector. The landscape of advanced PSE is poised to undertake a considerable transformation with the rise in popularity of open-source and script-based software platforms with predictive modelling capabilities based on modern mathematical optimization techniques. This paper highlights three leading equation-based platforms—IDAES, Modelica, and GEKKO-that are increasingly utilised for the modelling, simulation, and optimisation of complex systems within the advanced PSE domain, alongside the strengths and limitations of each approach. Following this, we present a framework through which emerging techniques within the domain of Software Engineering could be leveraged to address these limitations, with a vision of improving the accessibility and flexibility of... [more]

Accurately predicting biogas production for real-time applications remains a challenge in anaerobic digestion (AD) due to the process's complexity and dynamic nature. While mechanistic models are essential for understanding and modelling AD processes, however they are highly non-linear and depend on detailed feedstock characterisation and parameter calibration. In contrast, data-driven models do not rely on predefined equations and rather use process data to capture the system's underlying dynamics. This study compares mechanistic and data-driven models for biogas prediction using lab-scale data. A state estimation framework with a rolling window was used for the mechanistic model, based on biomass and substrate concentrations with Haldane kinetics, achieved an accuracy of (R² = 0.91). A Long Short-Term Memory (LSTM) model with Bayesian Optimisation for hyperparameter optimisation, trained on the same data showed superior performance (R² = 0.93–0.98) and captured temporal dependencies... [more]

Sustainable aviation fuel (SAF) is a proven alternative to reduce CO2 emissions in the aviation sector, supporting sustainable growth. However, SAF processes remain economically uncompetitive with fossil-derived jet fuel, prompting interest in strategies to address these challenges. In 2022, Carrasco-Suárez et al. explored process intensification in the SAF separation zone of a biorefinery using waste cooking oil (WCO), achieving a 3.07% reduction in CO2 emissions and lower operational costs for steam and cooling water. Despite these gains, the WCO biorefinery remains economically unviable with high energy demands. This work presents the energy integration of the entire WCO biorefinery addressed from the pinch point methodology, combined with separation zones intensification (EI-PI-S), using the principles of sections movement for distillation columns; these energy efficiency strategies were applied on the biorefinery in Aspen Plus V.10.0 in order to improve the scheme. Key indicators—... [more]

Reject brine discharge and high CO2 emissions from desalination plants are major contributors to environmental pollution. Managing reject brine involves significant costs, mainly due to the energy-intensive processes required for brine dilution and disposal. In this context, Solvay process represents a mitigation scheme that can effectively reduce reject brine salinity and sequestering CO2 while producing sodium bicarbonates simultaneously. The Solvay process represents a combined approach that can effectively manage reject brine and CO2 in a single reaction while producing an economically feasible product. Therefore, this study reports a systematic techno-economics assessment of conventional and modified Solvay processes, while incorporating brine and carbon tax. The model evaluates the significance of implementing a brine and CO2 tax on the economics of conventional and Ca(OH)2 modified Solvay compared to industries expenditures on brine dilution and treatment before discharge to the... [more]

This study evaluates the introduction of Carbon Capture and Utilization (CCU) process in two Colombian refineries, focusing on their potential to reduce CO2 emissions and their associated impacts under a scenario aligned with the Net Zero Emissions by 2050 Scenario defined in the 2023 IEA report. The work uses a MILP programming tool (Linny-R) to model the operational processes of refinery sites, incorporating a net total cost calculation to optimize process performance over five-year intervals. This optimization was constrained by the maximum allowable CO2 emissions. The methodology includes the calculation of surplus refinery off-gas availability, the selection of products and CCU technologies, and the systematic collection of data from refinery operations, as well as scientific and industrial publications. The results indicate that integrating surplus refinery fuel gas (originally used for combustion processes) and HTL bio-crude off-gas (as a source of biogenic CO2) can significantl... [more]

This study presents an economic analysis of a blue H2-N2 production system, using a novel intensified reformer system with a hydrogen production efficiency of 80%. The system’s ability to produce both high-purity H2 and N2 creates opportunities for small-scale blue H2 and distributed ammonia production. The system consists of three identical, optimized fixed-bed reforming reactors, a heat recovery system, and shift reactors. A dynamic model was developed to simulate three small-scale H2 production systems: 2.8 tpd, 7.1 tpd, and 17.1 tpd, enabling an evaluation of their economic viability. The results indicate that the cost of H2 production ranges from 2.7 to 3.1 USD/kgH2. Sensitivity analysis reveals that natural gas and CO2 transportation costs have a significant impact on the variability of H2 price. This research provides valuable insights into the economic feasibility of small-scale blue hydrogen production, offering a pathway to support the broader adoption of hydrogen technologie... [more]

This submission contains an Aspen Plus V12.1 file (.bkp) and a ProMax V6 file (.pmx) as part of the publication "Design of biocarbon by-product utilization processes for ironmaking and steelmaking". The Aspen Plus file contains a simulation of an autothermal reforming reactor for a bio-oil model using an RGibbs block, as well as heat exchangers and condensers used for determining equipment and utility costs. The ProMax file contains a simulation of a carbon dioxide removal process using an absorber and stripper loop with recycled MDEA solvent.

This document contains digital supplementary material (characterization of the case-studies, developed simulation models (and final configurations), optimisation models and post-processing assessments) related to the article entitled “The Paradigm of Water and Energy Integration Systems (WEIS): Methodology and Performance Indicators”, which is part of the peer reviewed conference proceeding of the 35th European Symposium on Computer Aided Process Engineering (ESCAPE 35). The present content has been adapted from the PhD thesis entitled "Simulation and Optimisation of Water and Energy Integration Systems (WEIS): An Innovative Approach for Process Industries".

Supplementary Material for the contribution "Synthesis of Distillation Flowsheets with Reinforcement Learning using Transformer Blocks" by Niklas Slager and Meik Franke (UTwente) for ESCAPE 35

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 several 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 efficient-ly, 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, ex-traction, 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 propo... [more]

This document contains supplementary material related to the article "Valorization of refinery fuel gas and biogenic gases from thermochemical conversion into low-carbon methanol", submitted to the 35th European Symposium on Computer Aided Process Engineering (ESCAPE 35).

The reduction and recovery of organic fraction of municipal solid waste is a major challenge for contemporary society. It requires the establishment of regional strategies with minimized environ-mental impact. This study employs life cycle assessment to evaluate the respective environmental performances of the current French system based on incineration, and those of alternative systems including (i) anaerobic digestion with composting and (ii) composting for biowaste treatment under different energy scenarios. The environmental impacts of Parisian waste are calculated by consid-ering the French energy mix in 2022, the average European energy mix in 2022 and the projected French energy mix for 2030. The results show that the proportion of fossil-based sources in the energy mixes significantly influences the environmental performance of waste management sys-tems. Systems with high fossil-based sources dependency tend to favour incineration-based pro-cessing systems. This is driven by th... [more]

This study evaluates, for the first time, the effects of UV/PMS and UV/H2O2/PMS processes on the degradation of sunscreen agents in synthetic and natural water matrices and compares their effectiveness with the more conventional UV/H2O2. Investigations were conducted using a mixture of organic UV filters containing 4-methylbenzylidene camphor (4-MBC) and 2-ethylhexyl-4-methoxycinnamate. Among the investigated UV-driven AOPs, UV/PMS/H2O2 was the most effective in synthetic water, while in natural water, the highest degradation rate was observed during the degradation of EHMC by UV/PMS. The degradation of UV filters in the UV/PMS system was promoted by sulfate radical (68% of the degradation), with hydroxyl radical contributing approximately 32%, while both radical species contributed approximately equally to the degradation in the UV/H2O2/PMS system. The Vibrio fischeri assay showed an increase in inhibition (up to 70%) at specific stages of UV/H2O2 treatment when applied to natural wat... [more]

To address the effect of a ship’s rolling on the fluidization quality of fluidized beds, in this study, a simulation of a rolling fluidized bed with longitudinal internal members added (R-FBLIM) was carried out and compared with that of a rolling fluidized bed without internal members added (R-FBWIM). The transient motion, as well as the behavioral characteristics of the bubbles within the R-FBLIM, was analyzed; the variation patterns of the number of bubbles, as well as the equivalent diameter of the bubbles, were compared for different apparent gas velocities, oscillation periods, and amplitudes; and the mechanism of the action of the longitudinal internal members was investigated. The results show that the structural design of the longitudinal internal members can effectively improve the gas−solid fluidization quality of the rolling fluidized bed. The horizontal support plate and the cap hole structure can effectively break the air bubbles, the cap hole structure promotes the radial... [more]

Healthcare professionals wearing personal protective equipment (PPE) during outbreaks often experience heat strain and discomfort, which can negatively impact their work performance and well-being. This study aimed to evaluate the physiological and psychological effects of a newly designed wearable cooling and dehumidifying system (WCDS) on healthcare workers wearing PPE via a 60 min treadmill walking test. Core temperature, mean skin temperature, heart rate, and subjective assessments of thermal sensation, wetness sensation, and thermal comfort were measured throughout the test. Additionally, ratings of wearing comfort and movement comfort were recorded during a wearing trial. The results showed that the WCDS significantly reduced core temperature, improved thermal sensation, and reduced wetness sensation compared to the non-cooling condition. The microclimatic temperature within the PPE was significantly lower in the cooling condition, indicating the WCDS’s ability to reduce heat bui... [more]

The proliferation of Sargassum biomass in various coastal areas has led to environmental and socio-economic problems. However, due to their unique composition, these biomasses offer versatile applications, prompting research into their potential in third-generation biorefineries. In this study, the hydrothermal processing of Sargassum sp. was evaluated under specific conditions at 190 °C/50 min and 150 °C/30 min. The resulting hydrolysates (liquid phase) were used as alternative culture media for cultivation. Nine treatments for the cultivation of Arthrospira platensis were assessed, varying the concentration of hydrothermal hydrolysates (HH) at 190 °C/50 min: T1 (5% v/v), T2 (10% v/v), and T3 (15% v/v). T4 (5% v/v), T5 (10% v/v), and T6 (15% v/v), maintaining the same HH conditions, and with the addition of 0.7 g/L NaNO3; and treatments T7, T8, and T9 had concentrations of 5%, 10%, and 15% of HH, respectively, at 150 °C/30 min with the addition of 0.7 g/L NaNO3, respectively. Each tre... [more]

Inspired by the vast potential of microalgae in the bioeconomy and the numerous applications and benefits associated with their cultivation, a multitude of pilot- and industrial-scale microalgae production systems have been developed in recent years. Both open and closed cultivation systems have been successfully utilized, with closed photo-bioreactors (PBRs) emerging as the most versatile option for various applications and products, enabling the implementation of advanced optimization strategies. Therefore, this short review provides a comprehensive overview of the different PBR configurations and their recent applications, primarily in large-scale but also in pilot- and laboratory-scale microalgae cultivation. A detailed discussion of the advantages, limitations, specific applications and recent advancements of each type of PBR is presented to aid researchers, engineers and industry stakeholders in selecting the most suitable PBR design for their specific goals and constraints. More... [more]