Search Results (426)

This work performed a sensitivity analysis based on a conventional extractive distillation system to thoroughly evaluate the cost of separating bioethanol from water. The analysis considers the compositions and production volumes that are likely to result from the fermentation process of various biorefineries, regardless of their specific generation. It also outlines how the cost of bioethanol purification decreases as the ethanol concentration in the fermentation broth increases. For each composition-flow point in a gridded workspace, a distillation train was designed using the Aspen Plus^® simulation framework, focusing on minimizing the total annual cost. The results are discussed graphically, illustrating total annual costs and specific column costs in relation to feed stream composition and inflow. The findings quantitatively demonstrate that the cost of separation per mass unit of anhydrous ethanol decreases with higher inflow and increased input ethanol concentration. Additionally, it is evident that the primary cost is associated with the preconcentrator column. Full article

The separation of carbon dioxide (CO₂) and hydrogen sulfide (H₂S) from sour natural gas is an important step in gas processing and emission control. This study applies a rate-based Aspen Plus simulation to examine solvent-based CO₂/H₂S removal under conditions representative of the Shurtan Gas Chemical Complex in Uzbekistan. Monoethanolamine (MEA) and methyldiethanolamine (MDEA) are evaluated as reference solvents with respect to separation performance and energy demand. The rate-based modeling framework accounts for reaction kinetics and mass transfer effects in the absorber–regenerator system. Simulation results indicate that both solvents achieve high acid gas removal efficiencies. From an engineering perspective, the results provide practical guidance for solvent selection and energy optimization in existing acid gas removal units, supporting pilot-scale deployment under industrial operating conditions. Sensitivity analysis suggests that increasing gas throughput beyond 30 t/h leads to a gradual reduction in CO₂ capture efficiency, primarily due to mass transfer limitations. From a techno-economic perspective, the lower energy demand of the MDEA-based system may imply reduced operating costs. The captured CO₂ stream reaches a purity of around 99.5%, which is compatible with downstream soda ash production. Overall, the results provide a screening-level assessment supporting further detailed evaluation. Full article

This article presents a dataset generated for a techno-economic assessment (TEA) of the methanol-to-jet (MtJ) fuel production pathway. The dataset was produced using a large-scale Monte Carlo (MC) sampling approach applied to a steady-state process model implemented in Aspen Plus V14. The techno-economic evaluation was conducted using an external cost model, with subsequent data processing performed in Python (Version 3.11). In total, three million individual data points were generated by varying key technical and economic input parameters within predefined ranges and are under public access. For each MC sample, the net production cost on a mass basis (NPC_m, EUR kg_jet-fuel⁻¹) of synthetic jet fuel was calculated as the primary economic performance indicator. The dataset comprises both the sampled input parameters and the corresponding techno-economic output variables and is intended to support transparency, reproducibility, and further uncertainty analysis of MtJ fuel production pathways. Full article

The electrochemical conversion of CO₂ into value-added aromatic carboxylic acids represents an emerging route for carbon utilization. This work investigates the regioselective electrochemical synthesis of ortho- and para-hydroxybenzoic acids (o-HBA and p-HBA) from CO₂ using a stirred batch cell, supported by a phenomenological Aspen Plus (version 12) model to assess process-level behavior. Experiments conducted at −1.2 V vs. Ag/AgCl, 3 atm CO₂, and 50 °C achieved yields of 58.4 ± 2.1% for o-HBA and 40.2 ± 1.6% for p-HBA, with a combined selectivity of 64.8%. Faradaic efficiencies were 76.2% (o-HBA) and 66.8% (p-HBA). A complete carbon balance, including dissolved inorganic carbon species, was established, demonstrating a single-pass CO₂ conversion of 42.6% and an overall conversion of 74.8% when the recycle loop was considered. Aspen Plus simulations based on ELECNRTL(Electrolyte Non-Random Two-Liquid model) thermodynamics and RYield fitting reproduced qualitative trends but underpredicted yields (21% and 9% for o- and p-HBA, respectively), reflecting the limitations of non-kinetic modeling. Sensitivity analyses confirmed that both electrolysis temperature and electrolyte concentration substantially influence yields and purity. This work provides reproducible electrochemical data, process-level mass balances, and a validated phenomenological simulation framework for future scale-up studies. Full article

The Aspen Plus process simulation with techno-economic assessment was used to evaluate the industrial-scale feasibility of enzymatic hydrolysis of corn stover. Choline chloride (ChCl)-based deep eutectic solvents containing lactic acid (LA), formic acid (FA), and acetic acid (AA) as hydrogen bond donors were used to pretreat the corn stover. Optimal pretreatment conditions (140 °C and a solid-to-liquid ratio of 1:30) achieved high levels of lignin (77.3%, 72.9% and 73.5%) and xylan (90.2%, 93.5% and 90.5%) removal for ChCl/LA (1:5), ChCl/FA (1:5) and ChCl/AA (1:5), respectively, while retaining significant levels of glucan (81.3%, 76.2% and 82%). Subsequent enzymatic hydrolysis at 10% substrate loading yielded glucose at 93.7%, 91.2% and 82.7%, respectively. The DES pretreatment and solvent recovery units accounted for 41.9% of capital costs at a solid-to-liquid ratio of 1:30. Increasing the solid-to-liquid ratio to 1:10 reduced total capital investment by 41.6%. Operational costs were heavily influenced by DES solvent consumption (81.2–92.7% of raw material costs). Of the DESs, the ChCl/FA (1:5) pretreatment process offered the best economic performance, achieving a minimum selling price (MSP) of USD 988.2 per ton. Sensitivity analysis identified glucose yield as the most critical cost driver (±20% variation caused a ±25% change in the MSP, followed by DES recycling efficiency. Fluctuations in DES prices had a limited impact (±20% variation caused a change in MSP of only 2.4–3.8%) due to the solvent recycling mechanism. This study demonstrates the potential of DES pretreatment for industrial application through process optimization, solvent recycling and valorization of by-products. Full article

The conversion of plastic waste into hydrogen offers a promising waste-to-value pathway, but its industrial viability is constrained by high external energy demand associated with thermochemical processing. This study evaluates the energy performance of hydrogen production from mixed plastic waste via pyrolysis and in-line steam reforming, with a focus on reducing utility consumption through systematic heat integration. A steady-state process model was developed in Aspen Plus for a representative mixture of polyethylene, polypropylene, and polystyrene, followed by detailed energy analysis and pinch-based heat integration using Aspen Energy Analyser. Baseline utility requirements were quantified and compared against optimised configurations incorporating targeted heat exchanger network modifications. The base-case analysis identified significant recoverable heat, enabling a reduction in total external utilities from 7.14 to 2.88 GJ h⁻¹, corresponding to a 59.6% decrease in utility demand. Sequential heat integration scenarios further reduced heating and cooling duties while maintaining process operability, demonstrating the effectiveness of iterative, pinch-guided design. The results show that high-temperature waste-plastic-to-hydrogen systems need not be utility-dominated when energy integration is embedded at the design stage. These findings highlight heat integration as a critical enabler for improving the energy efficiency and sustainability of pyrolysis–reforming routes and provide a robust framework for developing scalable, low-carbon hydrogen production from plastic waste. Full article

In this study, a techno-economic and carbon footprint (GHG, CO₂-equivalent) analysis was conducted on two alternative biofuels, green diesel and bio-jet fuel, produced from renewable lipids. The focus of the work is the comparison of various lipid feedstocks, including waste cooking oil, and four types of vegetable oils: cardoon, soybean, palm, and sunflower. Process optimization and design were performed to minimize production costs by using the process simulation software Aspen Plus^®. Green diesel and bio-jet fuel were obtained via hydrodeoxygenation and hydroisomerization/hydrocracking, respectively. Sensitivity analyses confirmed consistent results across the tested vegetable oils. Hydrodeoxygenation achieved triglyceride molar conversions exceeding 97%, with overall mass yields into the diesel fraction surpassing 79%. Conversely, hydroisomerization/hydrocracking of green diesel resulted in over 90% conversion of n-paraffins and more than 50% overall mass yield. The economic analysis showed that the primary cost factor influencing the payback selling price of the biofuels is the price of the lipid feedstocks. Biofuels are economically viable only when lipid prices are below 1000 €/ton and hydrogen prices are below 3000 €/ton. An important aspect is also represented by the combined-cycle energy recovery system, which strongly affects the overall capital cost and increases internal power generation efficiency. The carbon footprint calculated over a cradle-to-grave boundary showed shows net GHG reductions versus the fossil reference fuels for all scenarios. Net avoided emissions range from 1.74 to 3.63 kgCO₂-eq/kg green diesel and from 0.80 to 3.70 kgCO₂-eq/kg bio-jet fuel across the investigated feedstocks, approximately 40–84% and 20–95% of the respective savings relative to the fossil reference fuels under the stated background and logistics assumptions. Results are expressed per kg of produced fuel as a functional unit, using literature-derived upstream emission factors for oil supply and background inputs (hydrogen, Italian grid electricity and transport). For the bio-jet configuration, co-product burdens were partitioned by mass; the Discussion section highlights the sensitivity of the GD vs. BJF comparison to co-product handling and allocation choices. In this context, the choice of feedstock is essential in establishing the resulting GHG intensity of the two biofuels. From both economic and climate change perspectives, waste cooking oil emerges as the most promising option, particularly given its classification as waste-derived feedstock in the system boundary, unlike the virgin oil sources. Full article

Synthetic natural gas (SNG) production from biomass residues represents a promising strategy to reduce greenhouse gas emissions and enhance energy security in regions with abundant agricultural waste. This study evaluates the thermodynamic performance of SNG synthesis from rice husk (RH) and empty fruit bunches (EFB) bio-oils, major residues in the department of Bolívar, Colombia. The process was simulated in Aspen Plus^®, integrating syngas data and methanation under equilibrium conditions at 320 °C and 30 bar, complemented by hydrogen injection via alkaline electrolysis to maintain an H₂/CO ratio above 3. Energy and exergy analyses were performed to quantify efficiencies and irreversibilities. Results indicate carbon conversion rates of 48.3% for EFB and 47.4% for RH, producing SNG with 96% CH₄ suitable for grid injection. Energy efficiencies reached 71.9% and 71.0%, while exergy efficiencies were 87.2% and 82.9%, respectively, aligning with or surpassing literature benchmarks. The main irreversibilities occurred in methanation and CO₂ removal, highlighting thermal integration and gas recycling as key improvement strategies. These findings demonstrate the potential of leveraging local biomass for clean energy production and support the development of Power-to-Gas systems in Colombia. Full article

Biochar activation is critical for producing high-performance adsorbents; however, conventional activation methods are energy-intensive and difficult to control, particularly when air is used as an activating agent. This study investigates CO₂–air co-activation in a laboratory-scale fluidized bed reactor as an energy-efficient alternative. Experiments were conducted at 750–850 °C under varying gas flow rates with a constant CO₂/O₂ ratio. Optimal properties were achieved at 800 °C and 0.2–0.3 L/min CO₂, yielding a maximum BET surface area of 479 m²/g, a micropore contribution of 42%, and controlled carbon conversion (~25–35% yield). Aspen Plus equilibrium simulations also confirm that CO₂-only activation remains endothermic (heat duty up to +0.07 kW), air-only activation becomes strongly exothermic (down to −0.13 kW), while the CO₂–air mixture exhibits near-thermoneutral to mildly exothermic behavior (+0.13 to −0.10 kW), thereby reducing external energy demand potentially by approximately 60–70% compared with CO₂-only activation and significantly improving process stability. These results demonstrate that CO₂–air co-activation offers a practical route to produce high-quality activated biochar with controlled porosity and improved energy efficiency. Full article

The separation and purification of carbon dioxide (CO₂) from sour gas streams is critical for emission reduction and industrial reuse. This study presents a chemical absorption-based process simulation of CO₂ (carbon dioxide) and H₂S (hydrogen sulfide) separation using Aspen Plus V12.0, focusing on solvent-based treatment using an aqueous monoethanolamine (MEA) system selected based on industrial applicability and regeneration performance. The process was modeled for two gas streams originating from the Shurtan Gas Chemical Complex: a raw feed stream containing 3.42% CO₂ and 0.09% H₂S, and a treated dry gas containing 2.1% CO₂. The goal was to achieve high-purity CO₂ recovery (≥99.5%) with flow rates of 30 t/h and 20 t/h, respectively. Rate-based modeling was employed to simulate mass transfer and chemical kinetics in the absorber and regenerator columns. The simulation results indicated that at optimal solvent flow and absorber temperature (40–45 °C), over 98.6% CO₂ and 99.9% H₂S removal could be achieved. The specific energy requirement for solvent regeneration was estimated at 2.3 GJ per ton of CO₂, aligning with industrial efficiency benchmarks. The purified CO₂ is intended for use in the production of sodium carbonate (Na₂CO₃) at the Dehkanabad Potash Plant, which converts 20 t/h of CO₂ into 296,000 tons/year of calcined soda with 77% process efficiency. This approach enhances gas resource utilization while reducing atmospheric emissions. The model serves as a techno-economically viable foundation for scaling up CO₂ capture and utilization (CCU) in the Uzbek chemical industry. Full article

This study evaluates the techno-economic and environmental feasibility of hydrogen (H₂) production via co-gasification of woody biomass and polyethylene (PE) plastic waste, with and without carbon capture and storage (CCS), using an integrated modeling framework. Four scenarios were analyzed: (1) biomass gasification without CCS, (2) biomass with CCS, (3) co-gasification (90:10 biomass:PE) without CCS, and (4) co-gasification with CCS. Process simulations were conducted in Aspen Plus V12.1, techno-economic analysis (TEA) via NREL’s H₂A model, and cradle-to-gate life cycle assessment (LCA) in OpenLCA with TRACI 2.1 and the Cumulative Energy Demand (CED) methods. The plant processes 1500 dry ton/day feedstock, yielding ~136–140 tons/day pure H₂. TEA results show co-gasification without CCS achieves the lowest levelized cost of H₂ (LCOH) at 2.18 USD/kg, 7% below biomass-only (2.34 USD/kg), due to reduced feedstock demand and improved efficiency. CCS increases LCOH by 30–36% (2.98–3.18 USD/kg), but 70 USD/t CO₂ credits reduce it to 1.74–1.81 USD/kg, competitive with gray H₂. Sensitivity and Monte Carlo analyses highlight capacity factor and feedstock as key drivers, with co-gasification narrowing uncertainties. LCA reveals co-gasification lowers most impacts by 5–10%, while CCS enables net-negative GWP (−12.3 to −14.7 kg CO₂ eq/kg H₂) but raises CED by 15%. Scenario 4 balances economic viability and climate mitigation, supporting circular economy principles through waste valorization. Findings affirm co-gasification with CCS as a promising pathway for low-carbon H₂, with policy incentives critical for deployment. Future optimizations, like higher PE ratios, could further reduce costs below 2 USD/kg, advancing net-zero transitions. Full article

Conventional ammonia production via the Haber–Bosch process is energy-intensive and carbon-heavy. Emerging biomass-based approaches offer a sustainable alternative but often lack rigorous system-level analysis based on actual reaction kinetics. This study presents a novel integrated process coupling biomass pyrolysis/gasification with Chemical Looping Ammonia Generation (CLAG) and waste heat recovery. Unlike previous models relying on simplified assumptions, this simulation incorporates experimental kinetic data for both N-absorption and N-desorption stages to ensure high fidelity. The system’s energy and mass flows were rigorously evaluated using Aspen Plus. Results indicate that the gasification stage is optimal at an O₂/biomass molar ratio of 0.2 and 750 °C. In the CLAG unit, a higher N-absorption temperature (1600 °C) and α-Al₂O₃/C ratio (3:3) significantly enhance ammonia yield. Under these optimal conditions, the system achieves a remarkably low energy consumption of 10.12 GJ/t-NH₃ and specific CO₂ emissions of 3.2 t/t-NH₃—a reduction of over 60% compared to traditional coal-based routes. The integration of waste heat recovery is identified as a critical factor in minimizing net energy input. This work validates the feasibility of the biomass-based CLAG process as a low-carbon, energy-efficient pathway for sustainable ammonia synthesis. Full article

Colombia generates large volumes of lignocellulosic residues from agriculture, forestry, and agro-industrial activities. Much of this material is landfilled, openly burned, or left to decompose. These practices drive greenhouse-gas emissions (methane and CO₂), particulate air pollution, water contamination, and pest proliferation. Therefore, this study focuses on the design, simulation, exergetic and economic analysis of lignocellulosic biorefinery schemes in Colombia using corn stover (CS) as feedstock. This approach thus turns an environmental liability into valuable resources. Mass and energy balances obtained from Aspen Plus V10^® were used to calculate exergy efficiency. Economic indicators were provided by the Aspen Process Economic Analyzer (APEA) V10^® software. The first scenario (SCE01) included xylitol, lignin, carbon dioxide, biogas, and biofertilizer production along with in situ ethanol co-production; for scenario 2 (SCE02), a cogeneration (CHP) stage using biogas and biofertilizer as fuel was added; in scenario 3 (SCE03), the ethanol production of scenarios 1 and 2 was replaced by glutamic acid production. The exergy efficiency results were as follows: SCE01 (60.1%), SCE02 (36.8%), SCE03 (37.5%). The largest exergy losses were found in the CHP system. In terms of economic viability, all scenarios showed favorable economic parameters. SCE03 showed better results with an Internal Rate of Return (IRR) of 28.01% and a Net Present Value (NPV) of USD 985.1 M compared to SCE01 (27.48%; USD 769.1 M) and SCE02 (27.13%; USD 643.1 M). In light of these results, the SCE03 approach represents the most attractive investment opportunity, with the potential to integrate the social and environmental pillars of sustainability by fostering rural economic development and CO₂ capture. Optimization strategies can be readily adopted to enhance the overall efficiency of the proposed model, enabling it to serve as a benchmark for scaling and comparing alternative lignocellulosic waste valorization pathways at a national level. Full article

The global push for energy decarbonization has increased interest in hydrogen as a clean energy carrier. Biohydrogen from agricultural residues is a promising pathway for countries with strong agro-industrial sectors. This study evaluates the technical, economic, and environmental feasibility of hydrogen production from palm oil rachis in two post-conflict regions of Colombia: a large-scale facility in Bolívar and a small-scale plant in Santander. The assessment integrates Aspen Plus^® (version 14) simulations using the NRTL thermodynamic model, an attributional gate-to-gate Life Cycle Assessment (LCA) with ReCiPe Midpoint (H), and a techno-economic analysis. The simulated process includes biomass drying, decomposition, steam gasification, syngas cleaning, and methane reforming. A key technical finding was the non-linear relationship between feedstock composition and process yield. Although Santander’s biomass had a higher hydrogen content (9.42% vs. 6.58%), Bolívar achieved a much higher conversion efficiency (0.198 kg H₂/kg biomass) and produced over seven times more hydrogen while processing only 5.8 times more biomass. Environmental results showed clear advantages for Bolívar, which presented lower impacts across most categories compared to Santander and the fossil-based hydrogen benchmark. Bolívar achieved a Global Warming Potential of 2.47 kg CO₂ eq/kg H₂, far below the 15.03 kg CO₂ eq/kg H₂ of Santander, and showed favorable performance in particulate matter formation, acidification, and fossil resource scarcity. Economically, Bolívar was viable, with a Net Present Value of USD 25.01 million, a Benefit–Cost Ratio of 3.29, and a discounted payback period of 4.54 years. Santander was economically unfeasible under all conditions. Hydrogen production from palm rachis is technically feasible, environmentally beneficial, and economically viable when biomass availability and process integration are adequate, as illustrated by the Bolívar case. Full article

This study assessed the techno-economic performance and energy efficiency of scrap tyre valorization through pyrolysis in Nigeria, comparing two configurations: a pyrolysis plant integrated with power generation (Scenario 1) and a standalone pyrolysis plant (Scenario 2). Process simulations were carried out using Aspen Plus V12, and cost estimations were performed with the Aspen Process Economic Analyzer. For a feed capacity of 20 tons per hour, the pyrolysis process yielded steel wire (15.04%), char (35.57%), pyro-diesel (37.94%), gas (7.91%), and heavy oil (3.54%). Scenario 2 achieved a higher energy efficiency (94.44%) than Scenario 1 (51.23%). However, Scenario 1 demonstrated superior economic performance, with a Net Present Value (NPV) of USD 28.65 million and an Internal Rate of Return (IRR) of 34.48%, despite its higher capital investment of USD 27.63 million. Sensitivity analysis revealed that the selling price of pyro-diesel and the cost of scrap tyres were the most influential parameters affecting profitability. The findings provide useful insights for optimizing scrap tyre pyrolysis systems toward sustainable waste-to-energy applications in developing regions. Full article