Sustainable production of hydrogen, pyridine and biodiesel from waste-to-chemicals valorization plant: Energy, exergy and CO2-cycle analysis

This study deals with the simulation of waste-to-chemicals plant for the conversion of municipal solid waste to hydrogen, biodiesel and pyridine. The study analyses a Waste to Chemical plant, in order to evaluate the future scenarios of the integrated management of municipal waste from a technical and economic point of view and compare them, both in terms of material flows and related costs. In a first phase, the characteristics of the simulation model created with the help of the Aspen Plus software are analysed. Subsequently, with the help of a calculation model, the operating costs, emissions and energy and exergy efficiency are evaluated for the two identified scenarios. Starting from about 3000 t/h of waste, as a main result, about 8.4 t/h of pyridine and 300 t/h of biodiesel are produced and about 7.94 t/h of H2 as a by-product. The main purpose of the design cycle is to reduce the amount of waste to landfill, valorising it and limiting CO2 emitted in the atmosphere at the same time. Two system configurations are considered to maximize the reuse of all waste streams. In particular, the comparison was made between two scenarios: in the first the stream separated by extraction is considered a waste for the plant, while in the second scenario, this stream is sent to a fermentation section to obtain an excess bioethanol stream, which represents another product with high added value. The treatment of the stream separated from the extraction in the second scenario allows to obtain an additional stream of bioethanol in addition to the target products. A complete energy, exergy, environmental and economic analysis of the simulated plant have been carried out. The work shown that in the second case the waste exergy is dramatically reduced, leading to a raise of exergy efficiency from 30.2% up to 84.9%. While, from the environmental point of view both scenarios have low CO2 emissions, 0.52 kgCO2/kg products and 0.87 kgCO2/kg products respectively

Combined clean hydrogen production and bio-active compounds recovery from spent coffee grounds. A multi-perspective analysis

This study deals with the process simulation of an integrated system for energy production and valuable compounds recovery from spent coffee ground biomass and plasmix (non-recyclable plastic waste). The devised process consists of three maine units: a sub-critical water extraction column for the recovery of bio-compounds, an oxy-combustor of residual biomass and plasmix streams coupled with a production power energy unit, and a solid oxide electrolyzer (SOEC) for the production of pure H2 and O2. The process was exhaustively analyzed from an energy, exergy, environmental and economic point of view. The results of the analysis provided energy and exergy efficiencies higher than 60%, and the environmental analysis (CO2-cycle analysis) demonstrated a significant advantage of the process with respect to other hydrogen production methods. Finally, the feasibility of a plant with no net Greenhouse Gas emissions was shown to markedly depend on the costs associated to renewable energy sources

The Electrification of Conventional Industrial Processes: The Use of Mechanical Vapor Compression in an EtOH–Water Distillation Tower

The aim of this study is to analyze the exergetic, environmental, and economic impact of the electrification of a bio-refinery plant, considering the application of Mechanical Vapor Compression (MVC) to a conventional water–ethanol distillation column in the context of bioethanol production. The process was implemented in AspenPlus® and Aspen Exchange Design and Rating (EDR) simulation environments, where a sensitivity analysis was also carried out, considering four scenarios characterized by different compressions’ operative conditions, and including a Coefficient of Performance (CoP) analysis of the proposed solution with MVC. Exergetic and economic analyses were performed, and the relevant impacts on Operative Expenditure (OpEx) and Capital Expenditure (CapEx) were analyzed. Comparing the base case scenario with the proposed solution, a reduction of operative costs of around 63% was achieved. Finally, an environmental analysis was carried out, showing a remarkable reduction in the carbon footprint of the unit, with a carbon dioxide emission reduction of almost 80% for the MVC solution, in line with RED target requirements

The Electrification of Conventional Industrial Processes: The Use of Mechanical Vapor Compression in an EtOH–Water Distillation Tower

The aim of this study is to analyze the exergetic, environmental, and economic impact of the electrification of a bio-refinery plant, considering the application of Mechanical Vapor Compression (MVC) to a conventional water–ethanol distillation column in the context of bioethanol production. The process was implemented in AspenPlus® and Aspen Exchange Design and Rating (EDR) simulation environments, where a sensitivity analysis was also carried out, considering four scenarios characterized by different compressions’ operative conditions, and including a Coefficient of Performance (CoP) analysis of the proposed solution with MVC. Exergetic and economic analyses were performed, and the relevant impacts on Operative Expenditure (OpEx) and Capital Expenditure (CapEx) were analyzed. Comparing the base case scenario with the proposed solution, a reduction of operative costs of around 63% was achieved. Finally, an environmental analysis was carried out, showing a remarkable reduction in the carbon footprint of the unit, with a carbon dioxide emission reduction of almost 80% for the MVC solution, in line with RED target requirements