Alternative Production Processes Research Articles

Addressing the Difficulties and Opportunities to Bridge the Integration Gaps of Bio-Based Insulation Materials in the European Construction Sector: A Systematic Literature Review

Bio-based insulation materials (BbIMs) represent a potential alternative to conventional insulations, with their characteristics that favor a negative-carbon built environment. However, their use may face challenges that could prevent them from being used on a large scale in certain countries. The current study aims to provide focused insights into the practical difficulties and market opportunities for the application of BbIMs in Europe through a systematic literature review (SLR). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used as the basis for the conduct and reporting of this review. A keyword search was performed in Web of Science, Scopus, and ScienceDirect databases to select peer-reviewed English-language articles. HubMeta web tool was used to organize the selection process. The quantitative visualization of the literature was made by the Bibliometrix R package V4.1.4. Data were manually extracted and clustered in an Excel sheet. The review included 28 studies that have revealed interrelated insights. Difficulties range from regulatory and policy limitations and variability in performance, such as microbial growth and inconsistency in the behavior of materials under different conditions, to cost barriers. However, there are promising opportunities, including policy incentives and material performance benefits such as improved energy efficiency and indoor air quality. This research contributes to the literature by providing focused insights into the practical difficulties and market opportunities for the application of BbIMs in Europe. Research gaps and future perspectives point to the need for more field validation experiments, exploration of alternative production processes, and expanding life cycle assessment scopes to optimize their integration and performance. Stakeholders’ perceptions were made with a small sample in certain countries. Stakeholder perceptions were conducted with a small sample in some countries, so insights from stakeholders are needed to confirm or correct current findings.

Environmental Impact Assessment of a Plant Cell-Based Bio-Manufacturing Process for Producing Plant Natural Product Ingredients

Purpose: This study employed a Life Cycle Assessment (LCA) methodology to evaluate the environmental impacts of a novel plant cell-based biomanufacturing process for producing plant natural product ingredients. The primary purpose was to assess the relative sustainability of the process and to provide insights into potential areas of improvement in the biomanufacturing process. Method: The LCA method used an MS Excel (Ver. 2407) -based approach with a cradle-to-gate system boundary covering raw material sourcing (A1), raw material transportation (A2), and product extract manufacturing (A3) stages. Energy use and material inventory data are presented for different unit operations, and environmental impact factors were obtained from the Ecoinvent database. The study included a Material Circularity Index (MCI) calculation to assess the circularity of the biomanufacturing process for the production of saponin emulsifiers that are normally extracted from the woody tissue of the Chilean soapbark tree (Quillaja saponaria). Comparative analyses were performed against a wild-harvest approach for plant tannin extraction from spruce (Picea abies) tree bark. Key Results: The environmental impact assessment focused on determining relative Global Warming Potential (GWP), Acidification Potential (AP), Freshwater Eutrophication (FE), Particulate Matter Formation (PMF), and Ozone Depletion Potential (ODP). Results indicated that the extract manufacturing stage (A3) contributed significantly to adverse environmental impacts, with varying levels of effects based on the energy source used. Comparative analysis with the wild harvest approach highlights the lower environmental impact of the alternative biomanufacturing process. The biomanufacturing process showed a 23% reduction in GWP, AP, and FE and a 25% reduction in PMF and ODP relative to the wild harvest approach. However, the MCI for the biomanufacturing process was estimated to be 0.186, indicating a low material circularity. Conclusions: The results revealed that the extract manufacturing stage, particularly energy consumption, significantly influences the relative environmental impacts of the alternative production processes. Different energy sources exhibit varying effects, with renewable energy sources showing lower environmental impacts. The Material Circularity Index indicated a low circularity for the biomanufacturing process, suggesting opportunities for improvement, such as incorporating recycled or reused materials. Compared with the tannin extraction process, the plant cell-based biomanufacturing process demonstrated lower environmental impacts, emphasising the importance of sustainable practices and the use of renewable energy sources in future plant natural product sourcing. Recommendations include implementing more sustainable practices, optimising raw material choices, and extending product life spans to enhance circularity and overall environmental benefits.

Fueling the future with fungi: Efficient lipid extraction from Ganoderma Mycelium Biomass

Ganoderma lucidum mycelial biomass produced via submerged-liquid fermentation was subjected to different lipid extraction methods; soxhlet extraction (SXE), solvent extraction (SVE) and ultrasonic-assisted extraction (UAE), followed by a comparison in its lipid yield. The experiment was carried out using 5 g of biomass material, with 50-300 ml hexane solvent, and the temperature was set at 60 ° C for 1-9 hours. It was observed that the lipid yield was found to be influenced by the extraction time and solvent quantity. SVE was observed to be more effective for lipid production of 20.36 % (2 h and 100 ml hexane) in comparison with SXE (18.8 %) and UAE (7.50 %). In general, G. lucidum mycelial biomass may be used as a potential raw material and cost-effective solution for an alternative biodiesel production process in the future. Hence, future research work should focus on other novel extraction techniques as well as optimizing the other extraction parameters in improving the lipid yield from G. lucidum mycelial biomass.

Steam-assisted MILD-POX: A flexible process for the production of hydrogen

The aim of the present work is to propose an alternative hydrogen production process using water and sustainable feedstocks to promote the utilisation of cheap and renewable raw materials on a large scale by increasing flexibility, efficiency, and eco-compatibility of existing technologies without sacrificing their reliability and affordability. The idea is to combine non-catalytic Partial Oxidation and Moderate or Intense Low-oxygen Dilution combustion technologies by adding water. Thermodynamic equilibrium calculations, accompanied by kinetic modelling, are used to assess and interpret the general behaviour of a potential unit that uses the interaction of these two technologies and to compare the performances over a range of operating conditions of interest. The results show that thermochemical production of H2 using the proposed process is theoretically feasible and has the potential to offer many advantages over standard processes. The immediate advantage of such an approach is that a very high H2/CO ratio can be obtained that could eliminate the water gas shift conversion stages, making the reactor more compact and simple than conventional reformers. Moreover, water vapour addition limits the formation of soot precursors due to a “leaning” effect from releasing hydroxyl radicals.

An alternative process for bioethanol production from marine and freshwater algae using yeast for hydrolysis

This research develops a new process for production of bioethanol from marine and freshwater algae based on hydrolysis using yeast rather than the established methods of enzyme and acid hydrolysis. Yeast were isolated and adapted specifically for this process and the effectiveness of this hydrolysis was evaluated. This method was then evaluated within a full ethanol production process involving ozone pretreatment, and both hydrolysis and fermentation using yeast, under different nutrient supplementation regimes. The process effectiveness was evaluated for species of freshwater (Spirogyra hyalina) and marine (Kappaphycus alvarezii) algae. The yeast-based hydrolysis method outperformed acid and enzyme hydrolysis for both species of freshwater and marine algae, with particularly significant results for the freshwater algae. In the whole of process treatment, the yeast-based hydrolysis approach was effective when combined with ozone pretreatment for marine algae, and without any pretreatment for freshwater algae. The highest ethanol yield was achieved through fermentation with a yeast extract supplement present. These results indicate that ozone pretreatment, hydrolysis using yeast, and fermentation with the use of yeast extract as a nutrient are promising methods for economic ethanol production from seawater algae, and for freshwater algae where ozone pretreatment is not required.

A Review of Alternative Processes for Green Hydrogen Production Focused on Generating Hydrogen from Biomass

Hydrogen plays a leading role in achieving a future with net zero greenhouse gas emissions. The present challenge is producing green hydrogen to cover the fuel demands of transportation and industry to gain independence from fossil fuels. This review’s goal is to critically demonstrate the existing methods of biomass treatment and assess their ability to scale up. Biomass is an excellent hydrogen carrier and biomass-derived processes are the main target for hydrogen production as they provide an innovative pathway to green hydrogen production. Comparing the existing processes, thermochemical treatment is found to be far more evolved than biological or electrochemical treatment, especially with regard to scaling prospects.

Improvement of Process Conditions for H2 Production by Chemical Looping Reforming

A syngas production process was studied cyclically, exploiting the redox properties of Ce-based oxygen carriers. The two steps of the looping cycle were investigated through thermogravimetric analysis and fixed bed experiments. While TGA experiments were focused on the identification of the optimal temperatures ranges for methane partial oxidation (900–1000 °C) and carrier regeneration (400–900 °C), fixed bed testing was performed isothermally (at 900 or 950 °C), with a 10% CH4 feed stream in N2 to investigate material stability and cyclic performance reproducibility. The effect of the process times on carbon deposition, specific syngas yields, and selectivity was inspected, together with the investigation of best conditions to fully regenerate the carrier, adjust the syngas final ratio, and to ensure stable performances. The obtained results ensured the possibility to work in fully isothermal operations, with CH4 conversion of up to 38% and specific yields of syngas per mass of O2 carrier between 4.0–6.8 mmol∙g−1, preserved even across cycles, thus paving the path to the development of alternative and effective processes for syngas production. Under the operating conditions of the lab-scale experiment, an effective reforming time was 20 min, corresponding to 1.16 times of the characteristic time of reaction kinetics at 950 °C.

Numerical investigation of specific performance parameters of the S-ROTOR; a Savonius type turbine design

After the energy crisis in the 1970s, studies on alternative electrical energy production processes gained more importance especially considering the possibility of a new energy crisis that may come up nowadays. Despite their low power generation, s-rotor designs used in vertical axis wind turbines are open to development due to their features, such as producing high torque and having many configurations. In this study, the optimum s-rotor design is created using the aspect ratio, overlap ratio, quarter blade gap ratio, and fin as parameters. The effective levels of each parameter were found by performing Computational Fluid Dynamic analysis. Then, using the Responds Surface Optimization method, optimum parameter levels were determined, and the optimum s-rotor design was created. The findings showed that the newly designed s-rotor provided a remarkable performance increase in high tip-speed ratios. In addition, the maximum power coefficient of the s-rotor increased from about 0.06 to 0.10, and it was determined that the aspect ratio was more effective on the power coefficient than the other parameters.

Modeling the Selectivity of Hydrotalcite-Based Catalyst in the Propane Dehydrogenation Reaction.

The propylene production processes currently used in the petrochemical industry (fluid catalytic cracking and steam cracking of naphtha and light diesel) are unable to meet the increase of propylene demand for industrial applications. For this reason, alternative processes for propylene production have been investigated, and among the others, the propane dehydrogenation (PDH) process, allowing the production of propylene as a main product, has been industrially implemented (e.g., Catofin and Oleflex processes). The main drawback of such processes is closely linked to the high temperature required to reach a sustainable propane conversion that affects catalyst stability due to coke formation on the catalyst surface. Accordingly, the periodic regeneration of the catalytic bed is required. In this work, the performance in the PDH reaction of different Sn-Pt catalysts, prepared starting by alumina- and hydrotalcite-based supports, is investigated in terms of propane conversion and selectivity to propylene in order to identify a more stable catalyst than the commercial ones. The experimental tests evidenced that the best performance was obtained using the catalyst prepared on commercial pellets of hydrotalcite PURALOX MG70. This catalyst has shown, under pressure conditions of 1 and 5 bar (in order to evaluate the potential future application in integrated membrane reactors), propane conversion values close to the thermodynamic equilibrium ones in all of the investigated temperature ranges (500-600 °C) and the selectivity was always higher than 95%. So, this catalyst was also tested in a stability run, performed at 500 °C and 5 bar: the results highlighted the loss of only 12% in the propane conversion with no changes in the selectivity to propylene. Properly designed experimental tests have also been performed in order to evaluate the kinetic parameters, and the developed mathematical model has been optimized to effectively describe the system behavior and the catalyst deactivation.

Effects of Seed Germination on Physicochemical and Bioactive Compounds Characteristics of Velvet Bean Tempe

Indonesia, known as the largest tempe-producing country globally with approximately 160,000 producers, faces a challenge in meeting the demand for tempe due to insufficient local soybean supply. To address this issue, Indonesia has been compelled to import significant quantities of soybeans, reaching 1.68 million tons in 2020, which escalated by 47.78% to 2.49 million tons in 2021. This study aims to scientifically investigate the impact of velvet bean seed germination on the physicochemical characteristics and bioactive components of velvet bean tempe. The research methodology involved quantitative analysis to obtain reliable results. The preliminary analysis established that the optimal velvet bean tempe fermentation time was 48 hours. Following germination, the physical properties of velvet bean sprouts exhibited an increase in weight accompanied by a reduction in bulk density and absolute density. Furthermore, the germination treatment resulted in decreased brightness, saturation, whiteness, and pH values, while simultaneously increasing the hardness of the tempe. Chemical analysis demonstrated that germination of velvet bean seeds led to an elevation in moisture content and a decrease in carbohydrate content within the produced tempe. Additionally, bioactive component analysis revealed that the germination treatment contributed to a reduction in total phenol content from 52.46 to 36.30 mg AAE/100g, antioxidant capacity from 132.80 to 66.90 mg GAE/100g, and GABA content from 54.20 to 21.50 mg/100g in the tempe. These findings provide valuable scientific insights into alternative ingredient utilisation and production processes optimisation of velvet bean tempe.

Clean Production of Hydrogen Peroxide: A Heterogeneous Solar‐Driven Redox Process

AbstractHydrogen peroxide is an essential chemical that is attracting strong attention for energy and environmental applications. However, the struggle between the growing market demand and the unsustainability of the conventional anthraquinone method motivates the exploration of alternative H2O2 production processes. Although several new production processes have been proposed, the environmental‐friendly solar‐driven H2O2 production attracts most attention because of the only inputs of water, oxygen, and light energy. The rational design of functional photo‐responsive catalysts promotes H2O2 production in the photocatalytic and photoelectrocatalytic approaches. These are, in general, achieved by facilitating the preferential adsorption of key intermediates of OOH*/OH*/O*, enhancing the light absorption, promoting the charge separation, and accelerating the surface charge transfer with selective number of involved charges. This review systematically summarizes strategies for photo(electro)catalysts toward H2O2 production via both the water oxidation and oxygen reduction pathways. Though the oxygen reduction route is perceived as more popular in the community, selective water oxidation is emerging as a convincing alternative. Furthermore, prevailing hypotheses, state‐of‐the‐art catalysts, critical challenges, and perspectives are discussed in depth. This review aims to enhance the comprehension of this research field and promote interest in sustainable H2O2 production.

Economic Analysis of an Integrated Steel Plant Equipped with a Blast Furnace or Oxygen Blast Furnace

The oxygen blast furnace with top gas recycling (TGR-OBF) ironmaking technology can reduce CO2 emissions, especially when combined with carbon capture and storage technology (CCS). However, the successful commercialization of technology cannot be achieved without economic evaluation. This study applied the Box–Behnken design method and a Monte Carlo simulation-based risk analysis to assess the sensitivity of influencing factors affecting the net present value (NPV) of an integrated steel plant (ISP) and to predict the impact of variable market scenarios on the NPV of three ISPs. The results indicated that among the three ISPs, the conventional ISP (C-ISP) is the least profitable, followed by the ISP equipped with TGR-OBF and CCS (ISP-OBF-CCS), and the most profitable is the ISP equipped with TGR-OBF (ISP-OBF), which is at least CNY 0.392 Bn and CNY 1.934 Bn more profitable than the ISP-OBF-CCS and C-ISP respectively. Under the current Chinese carbon trading policy and the cost of CCS, CCS technology does not make a company profitable. This study explored an approach for analyzing ISP economic applicability under uncertain markets, which can be used as a reference for the development of alternative processes for steel production.

Development and lifecycle assessment of various low- and high-density polyethylene production processes based on CO2 capture and utilization

This work focuses on the design and analysis of innovative environmentally friendly pathways to produce low-density polyethylene and high-density polyethylene, as the main feedstock of petrochemical industries, based on CO2 capture and utilization. For each polymer, the process development and simulation of the proposed pathways are performed using Aspen Plus. Each pathway includes the following units: CO2 capture from flue gas, hydrogen production via electrolysis of water, methanol production, olefin production, and polymerization of ethylene. Moreover, the greenhouse gas emissions of the proposed pathways are compared to those of the conventional method i.e., steam cracking. The midpoint and endpoint lifecycle assessment of each pathway are conducted using TRACI 2.1 and ReCiPe Endpoint (H, A) lifecycle impact assessment methods in the OpenLCA software, respectively, for various geographical locations, electricity sources and assessment scenarios for the incorporation of the by-products. The lifecycle assessment results show that the new pathway is an environmentally attractive option, particularly in regions where renewable (low-carbon) electricity is more prominent, such as Quebec and Ontario provinces in Canada. In such regions, negative CO2 emissions, as low as −6.1 kg CO2eq/kg polymer, can be achieved. However, in locations where coal or natural gas are the main sources of electricity generation, such as Alberta, lifecycle emissions increase to 20 times the emissions of the conventional method. Furthermore, the impact of incorporating alternative methanol production processes is evaluated. Results show that using the tri-reforming of methane as an effective syngas production technology from CO2 and natural gas can reduce the lifecycle greenhouse gas emissions by up to 94% and 62%, compared to the conventional high- and low-density polyethylene production pathways.

Filling in the gaps in biowaste biorefineries: The use of the solid residue after enzymatic hydrolysis for the production of biopesticides through solid-state fermentation

Alternative production processes using waste are necessary to preserve non-renewable resources and prevent scarcity of materials for future generations. Biowaste, the organic fraction of municipal solid waste, is abundant and easily available. It can be fractionated into building blocks for which fermentative processes can be designed. By using solid-state fermentation, this paper proposes a method of valorizing biowaste’s residual solid fraction after enzymatic hydrolysis. In a 22 L bioreactor, two digestates from anaerobic digestion processes were evaluated as cosubstrates to modify the acidic pH of the solid residue after enzymatic hydrolysis and promote the growth of the bacterial biopesticide producer Bacillus thuringiensis. Regardless of the cosubstrate used, the final microbial populations were similar indicating microbial specialization. The final product contained 4 × 108 spores per gram of dry matter and also crystal proteins of Bacillus thuringiensis var israelensis, which have insecticidal activity against pests. This method allows for the sustainable use of all materials liberated during the enzymatic hydrolysis of biowaste, including residual solids.

Dynamic material flow analysis of Chinese ethylene production processes and optimal pathway exploration with potential environmental-economic impacts

China is expected to become the largest ethylene producer globally; environmental problems related with traditional ethylene production process of Chinese petrochemical industry will be further stern. This study aims to propose a feasible and optimal ethylene production expansion pathway to improve the trade-off between the environment and economy. A novel approach was adopted with material-energy-value flow analysis integration by combining dynamic scenario analysis. According to the results of scenario analysis, cleaner and lightweight production processes optimization achieved by adopting the alternative ethylene production process mix alleviated environmental pressure and achieved a weak decoupling of the low-carbon economy. A 26.1% increase in carbon productivity was achieved compared with the baseline scenario, whereas the coal to ethylene route should be phased-out, as more than 90% of the pollutants are generated by 10%–17% of the coal to ethylene facilities. However, CO2 emissions from ethylene will inevitably increase along with doubling ethylene production. An imbalance in pollutant generation also emerges if large-scale naphtha is exclusively promoted for ethylene plant implementation. The study provides methodological support for investigating feasible roadmaps for key product capacity expansion, and has practical meaning for high-quality industrial development domestically and globally.

Quantitative analysis of CO2 emissions reduction potential of alternative light olefins production processes

Steam cracking with electrical furnaces avoids combustion-related CO2 emissions using approximately 3 MWh/t olefins while alternative CO2-based olefins production achieves larger CO2 emissions reductions but requires five times more electricity

Anaerobic microbial cocktail of lignocellulolytic fungi and bacteria with methanogens for boosting methane production from unpretreated rice straw

Rice straw (RS) has been recognized as a sustainable renewable energy resource for converting into sugars and volatile fatty acids (acetate, propionate, and butyrate) and subsequently to produce biogas. Enhanced production of these intermediates from RS by the different combinations of two consortia was investigated. Anaerobic microbial cocktails of fungi, bacteria, and methanogens were evaluated for performance and stability in the anaerobic digestion of untreated RS. The best-defined anaerobic microbial cocktail for high RS degradation and methane production, consisting of anaerobic bacteria (mainly Proteiniphilum acetatigenes, Pyramidobacter piscolens, and Mesotoga prima) and anaerobic lignocellulolytic/fermentative fungi (uncultured Neocallimastigales, Orpinomyces, Anaeromyces, and Feramyces sp.) at a copy number ratio of 103-105 copies/mL, including hydrogenotrophic and acetoclastic methanogens (Methanosarcina mazei, Methanoculleus marisnigri, Methanofollis liminatans, Methanoculleus bourgensis, and Methanosaeta harundinacea) concentration of 106 copies/mL, was successfully constructed. The system performance was 80% VS (volatile solids) RS degradation, 34mL/day methane production rate, 318mL/g VSadded methane yield, and a pH range of 6.90-7.70 within a short time of 14days. A defined microbial cocktail has been proven as a potential alternative process for lignocellulose hydrolysis and methane production.

Comparison by Life-Cycle Assessment of Alternative Processes for Carvone and Verbenone Production.

Verbenone and carvone are allylic monoterpenoid ketones with many applications in the fine chemicals industry that can be obtained, respectively, from the allylic oxidation of α-pinene and limonene over a silica-supported iron hexadecachlorinated phthalocyanine (FePcCl16-NH2-SiO2) catalyst and with t-butyl hydroperoxide (TBHP) as oxidant. As there are no reported analyses of the environmental impacts associated with catalytic transformation of terpenes into value-added products that include the steps associated with synthesis of the catalyst and several options of raw materials in the process, this contribution reports the evaluation of the environmental impacts in the conceptual process to produce verbenone and carvone considering two scenarios (SI-raw-oils and SII-purified-oils). The impact categories were evaluated using ReCiPe and IPCC methods implemented in SimaPro 9.3 software. The environmental impacts in the synthesis of the heterogeneous catalyst FePcCl16-NH2-SiO2 showed that the highest burdens in terms of environmental impact come from the use of fossil fuel energy sources and solvents, which primarily affect human health. The most significant environmental impacts associated with carvone and verbenone production are global warming and fine particulate matter formation, with fewer environmental impacts associated with the process that starts directly from turpentine and orange oils (SI-raw-oils) instead of the previously extracted α-pinene and limonene (SII-purified-oils). As TBHP was identified as a hotspot in the production process of verbenone and carvone, it is necessary to choose a more environmentally friendly and energy-efficient oxidizing agent for the oxidation of turpentine and orange oils.

Environmental assessment of a two-stage high pressure anaerobic digestion process and biological upgrading as alternative processes for biomethane production

Biomethane plays a key role in achieving decarbonization and sustainable development goals. According to the objectives that arise, choosing the most suitable production system allows optimization of production, thereby reducing CO2 emissions. In this study, three biomethane production scenario life cycle assessments were compared to determine which would maintain the lowest CO2 emissions. Conventional anaerobic digestion and an innovative process called two-stage high pressure anaerobic digestion were considered. These methods were combined with two upgrading processes: water scrubbing and biological upgrading. Cattle manure and sugar beets were used as substrates for the process. Emissions were 805.6 gCO2eq/m3CH4 for the traditional biogas production process combined with water scrubbing and 450.3 gCO2eq/m3CH4 for the two-stage anaerobic digestion process combined with biological upgrading. Furthermore, the analysis demonstrated that these values would be reduced by 29.5 % and 48.0 % if electrical energy were produced using only renewable energy sources.

Environmental Performance Assessment of a Novel Process Concept for Propanol Production from Widely Available and Wasted Methane Sources.

Currently, propanol production highly depends on conventional fossil resources. Therefore, an alternative production process, denoted as “C123”, is proposed and evaluated in which underutilized and methane-rich feedstocks such as biogas (scenario BG), marginal gas (scenario MG), and associated gas (scenario AG) are converted into propanol. A first modular-scale process concept was constructed in Aspen Plus, based on experimental data and know-how of the C123 consortium partners. The environmental performance of the considered scenarios was compared at the life cycle level by calculating key performance indicators (KPIs), such as the global warming burden. The results showed that scenario BG is the least dependent on fossil fuels for energy use. Scenario AG seems the most promising one based on almost all selected KPIs when taking into account the avoided gas flaring emissions. The performance of the C123 process concept could be improved by applying heat integration in the process concept.