In this study, we evaluate the economic and environmental impacts of integrating waste polyethylene (PE) pyrolysis with naphtha-based steam cracking for 660 Mt/y ethylene production. We compare six integration scenarios to both business-as-usual (BAU) steam cracking and greenfield waste PE pyrolysis plant. We perform process simulations and equipment design in Aspen Plus® V12, followed by a techno-economic analysis (TEA) and a life-cycle assessment (LCA. The integration capacity we considered corresponds to one full-capacity PE pyrolysis furnace, reducing naphtha feed by 7% in BAU steam cracking. Through the TEA, we identify the most cost-effective scenario by merging the PE pyrolysis gas with the steam cracker furnace outlet after preheating the PE feed. This integration reduces production costs by 6.46MM€/y, improving costs a 0.3% compared to BAU and 30% compared to the pyrolysis greenfield design. LCA results show that the greenfield pyrolysis plant achieves the lowest global warmin... [more]

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]

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]

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 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]

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]

Steel mill off gas fermentation presents a promising green alternative to petrochemical isopropyl alcohol (isopropanol, IPA) and acetone production while potentially reducing greenhouse gas emissions. A pilot-scale study stated negative global warming potential (GWP) at 85% gas conversion and 90% product selectivity. However, industrial-scale plant design including detailed techno-economic assessment (TEA) and life cycle assessment (LCA) remain undescribed. Therefore, this study modelled a heat-integrated 47.5 kton/ year gas fermentation process to IPA and acetone, based on pilot-scale data. The downstream processing was designed using vacuum distillation and heat-pump integrated (extractive) distillation to purify the 50 gproduct/ L broth with biomass and acetate as byproducts, to obtain 41.8 kton/ year of 99.6 wt. % IPA and 5.64 kton/ year of 99.0 wt. % acetone. Notably, no steam is consumed and 2.6 MWh of electricity is generated by utilising the energy from the steel mill off gas.... [more]

Oxidation of arabinose to arabinoic acid is an innovative way to valorize local biomass to a high add value product. Previously done experiments on oxidation of arabinose to arabinoic acid with molecular oxygen were used to determine the optimum reaction conditions, scale-up the process and analyse the techno-economic aspects. These results were utilized to analyse the environmental impact of the scaled-up process during its lifetime using the life cycle assessment (LCA) methodology. SimaPro software combined with the impact assessment method IMPACT 2002+ were applied. The results revealed that heating seems to be the largest contributor to the environmental impact even if the reaction is performed under rather mild conditions (70oC). This highlights the importance of reducing the energy consumption via efficient heat integration.

The pulp and paper industry has significant potential to reduce its carbon footprint by optimizing energy and water usage, contributing to global efforts toward net-zero emissions. A critical unit operation in this industry is pulp washing using twin roll press washers, which enhance pulp quality. The filtrate from this unit operation can be concentrated and combusted to generate a significant amount of energy for the plant and nearby industries. However, these washers are prone to blockages that disrupt production and decrease energy efficiency. Despite their importance, models for managing blockages in twin roll press washers are lacking. This study addresses this gap by developing empirical models to predict roll speed based on key process parameters. These models performed well on a case study of un-sanitized data from a real pulp and paper plant, achieving R2 of the order of 0.7. The models can potentially be used by operators to ensure uninterrupted production, and optimize resou... [more]

This document is supplementary material for the full paper titled "Flow Simulation of Plastic Life Cycle Considering Carbon Renewability and Environmental Impact," submitted for the ESCAPE 35 conference. It includes a detailed explanation of the system boundary construction method used in the flow analysis, as well as the data sources for information such as the GHG emission intensities, which could not be explained in the main text.

This document contains digital supplementary material (LCA model including parametrized LCI with sources, unit processes and LCA results) related to the article "Integrated LCA and Eco-design Process for Hydrogen Technologies: Case Study of the Solid Oxide Electrolyser" which is submitted to the peer reviewed conference proceeding of the 35th European Symposium on Computer Aided Process Engineering (ESCAPE 35).

Deploying engineered carbon dioxide removal strategies like direct air capture (DAC) will be
imperative to meet net-zero targets, given the biophysical constraints associated with land-based
methods. Thoroughly devised deployment pathways for DAC could ease the financial burdens of
adopting the technology at climate-relevant scales. Key drivers for the optimal regional rollouts of
DAC include the available energy supply and geological capacities for CO2 storage. These factors
also impose temporal constraints considering the evolving nature of energy systems and the
development of CO2 transport and storage infrastructure over time. As DAC technologies exhibit
differences in their system demands, integrating various methods into deployment strategies may
address potential trade-offs arising from regional resource endowments. Commercial-ready options
use solid sorbents or liquid solvents, while emerging methods extend to electrochemical devices
like bipolar membranes. These tech... [more]

The research focuses on optimizing vegetable oil production processes for human consumption, emphasizing green and efficient extraction methods using renewable solvents with minimal toxic residues. Pressurized liquid extraction (PLE), especially with ethanol, is studied for its efficiency and low solvent usage in intermittent processes. By evaluating extraction parameters and kinetics, the study aims to determine optimal conditions for higher extraction rates and yields, providing insights into production costs and other factors. Specifically, the research examines the behavior of extraction kinetics for vegetable oils like rice bran, sunflower seeds, and rolled soybeans. It also seeks to determine mass diffusivity in semi-continuous processes and to model PLE in intermittent processes using Fick’s Law and Mathematica Wolfram Software v11.2. The effective diffusivity (Deff) for rice bran oil in pressurized ethanol varied between 13.09 and 15.70 × 10−12 m2/s, and the Deff value of sunfl... [more]

Gravity settling is a widely employed technology that removes oil from produced water in oilfields. However, with the transition of reservoir development to low-permeability reservoirs, conventional produced water settling tanks face limitations in the treatment efficiency and coagulant dosage. This study presents an innovative approach that optimizes sedimentation tank structures and integrates micro-vortex flow technology to enhance coagulation and flocculation. Through chemical dosage experiments, comparative experiments, and long-term observation, the micro-vortex flow reactor demonstrates a 9.4% increase in oil removal efficiency while reducing the coagulant dosage by 30.0%. The MOR equipment achieved a 20.5% higher oil removal efficiency than conventional methods while maintaining effluent oil and suspended solids below 20 mg/L. The long-term observation experiment of MOR equipment further highlights oil removal efficiency of 94.2% and the micro-vortex reactor’s excellent anti-po... [more]

Upon reaching deeper levels of extraction, dynamic hazards such as rockburst become more pronounced, with the high energy storage characteristics of rock masses in high-stress environments being the fundamental factor behind rockburst disasters. Additionally, deep-seated mineral extraction commonly involves drilling and blasting methods, where the vibrational energy generated by mining explosions combines with the elastic energy of rock masses, leading to a sudden growth in the risk and intensity of rockburst disasters. This paper, with deep mining at Sanshandao Gold Mine as the focal point, systematically investigates the impact of blasting vibrations on rockburst disasters in deep mines. Initially, based on extensive data on measured geostress considering the tri-arch cross-section form of deep tunnels, the elastic energy storage of the surrounding rocks in deep tunnels was calculated. The results indicate that the maximum energy storage of the surrounding rocks occurs at the bottom... [more]

As interest in additive manufacturing (AM) continues to increase, it has become more important to have a robust method to help potential users select the AM process that best suits their technological needs while providing the greatest potential benefits in terms of sustainability and its effect on people. This paper presents the development of a framework for selecting the best AM process for a given application by considering both sustainability and human factors through the combination of axiomatic design and the analytic hierarchy process. Thirty-one participants with varying levels of expertise (novice and advanced users) were involved in the study, considering the frequency of 3D printer usage (novice users: never, rarely; expert users: sometimes, almost always, always) for prototyping parts. They employed fused deposition modeling (FDM) and stereolithography (SLA) (both 3D desktop printers) and collected data on five evaluation criteria. The participation of experts helped estab... [more]

The interest in combined heat and solar power (CHP) systems has increased due to the growing demand for sustainable energy with low carbon emissions. An effective technical solution to address this requirement is using a parabolic trough solar collector (PTC) in conjunction with a Rankine cycle (RC) heat engine. The solar-powered Rankine cycle (SPRC) system is a renewable energy technology that can be relied upon for its high efficiency and produces clean energy output. This study describes developing a SPRC system specifically for electricity generation in Aden, Yemen. The system comprises parabolic trough collectors, a thermal storage tank, and a Rankine cycle. A 4E analysis of this system was theoretically investigated, and the effects of various design conditions, namely the boiler’s pinch point temperature and steam extraction from the high-pressure turbine, steam extraction from the intermediate-pressure turbine, and condenser temperature, were studied. Numerical simulations show... [more]

Mercury pollution is a serious public health problem. China’s extensive use and reliance on mercury has led to water pollution, particularly the presence of methylmercury in water. Estimating total mercury emissions from wastewater in China is challenging due to the large amount and wide range of emissions. An estimation model for total mercury content in sewage in China was established by establishing a relationship between sewage treatment volume, mercury content in effluent after sewage treatment, and the data of sludge production and mercury content in the sewage treatment plant. It was determined that only 3% of mercury entered the air during sewage treatment, 27.5% of mercury entered the effluent, and about 69.5% of mercury entered the sludge, based on the treatment of existing wastewater treatment plants in China. From 2002 to 2021, the average annual sewage mercury emission in China was 32.07 Mg, and the emissions were higher in densely populated and economically developed prov... [more]

Tanneries generate copious amounts of potentially toxic sludge and effluent from the processing of skins and hides to leather. The effluent requires remediation before discharge to protect the receiving environment. A range of physicochemical methods are used for pre- and post-treatment, but biological secondary remediation remains the most popular choice for the reduction of the organic and macronutrient fraction of tannery effluent. This review provides an update and critical discussion of biological systems used to remediate tannery effluent. While the conventional activated sludge process and similar technologies are widely used by tanneries, they have inherent problems related to poor sludge settling, low removal efficiencies, and high energy requirements. Treatment wetlands are recommended for the passive polishing step of beamhouse effluent. Hybrid systems that incorporate anoxic and/or anaerobic zones with sludge and/or effluent recycling have been shown to be effective for the... [more]

This study presents an economic optimization model for determining the optimal insulation thickness for both thermal insulation and electric tracing pipelines. Using Life-Cycle Cost (LCC) analysis, optimization research was conducted under various working conditions to identify the most cost-effective insulation thickness. Factors such as pipe diameter, operational duration, drilling fluid temperature, and heat cost were analyzed to assess their impact on the economic thickness of the insulation layer, specifically within the unique environment of drilling sites. The results provide the economic thickness and total cost for both insulated and electrically traced pipelines under different scenarios. For instance, for a DN100 pipe with rock wool insulation operating for 3600 h, the economic thickness of the electrically traced pipe insulation was determined to be 5.18 cm greater per unit length compared to the non-electrically traced pipe, resulting in an additional cost of 19.36 CNY/m.... [more]

The growing demand for lithium-ion batteries (LIBs) has led to significant environmental and resource challenges, such as the toxicity of LIBs’ waste, which pose severe environmental and health risks, and the criticality of some of their components. Efficient recycling processes are essential to mitigate these issues, promoting the recovery of valuable materials and reducing environmental pollution. This review explores the application of electrodialysis in the process of recycling LIBs to contribute to the principles of circular hydrometallurgy. The article is structured to provide a comprehensive understanding of the topic, starting with an overview of the environmental and resource challenges associated with manufacturing LIBs. Then the current recycling processes are presented, focusing on hydrometallurgical methods. The concept of circular hydrometallurgy is introduced, emphasizing sustainable resource recovery. The electrodialysis technique is described in this context, highlight... [more]

This study aims to evaluate the emissions of greenhouse gases (GHGs) stemming from the sludge treatment sector in China and to investigate the feasibility of novel technologies in curtailing these emissions, with the aim of fostering sustainable sludge management methodologies. Employing a life-cycle assessment (LCA) methodology, the research computed the comprehensive GHG emissions resulting from sludge treatment, taking into consideration diverse elements such as treatment techniques (e.g., landfills, incineration, and land application) and the geographical variations among China’s 660 municipalities. Findings indicate that the total amount of GHG emissions from sludge treatment amounted to 18.54 Mt CO2-eq in 2017, with incineration registering the highest emissions (10,011.53 kg CO2-eq/t dry sludge (DS)), followed by landfills (717.51 kg CO2-eq/t DS) and land application (276.41 kg CO2-eq/t DS). The geographical dispersion of emissions characteristics reveal notable regional dispari... [more]

The climate crisis, driven by increasing CO2 levels in the atmosphere, has heightened the need for new, environmentally friendly energy sources. Hydrogen gas, which can meet our energy needs, has become a particularly intriguing topic. This study investigated the partial oxidation reaction of methane with cordierite monolith catalysts. The Ni-coated catalysts were supported with γ-Al2O3, CeO2, ZrO2, and CeO2-ZrO2. The catalysts were tested at temperatures of 750, 800, and 850 °C with different flow rates and methane feed concentrations (2%, 5%, and 10%). It was demonstrated that catalyst activity varies depending on these parameters. It has been found that high gas hourly space velocity (GHSV) and CH4 feed rates decrease catalyst activity. The obtained reaction results indicated that the optimal reaction parameters were 800 °C, a GHSV of 1 × 104 h−1, and a CH4 feed concentration of 2%. By optimizing these parameters, catalysts with high CH4 conversion and selectivity for H2 and CO were... [more]

Substance separation has always been the foundation of production processes in a variety of industrial sectors such as hydrometallurgy, natural compounds extraction, food industry, pharmaceutical industry, and environmental engineering [...]