Economic Comparison Research Articles

Gellan-amino acid hydrogel-based bioreactor for optimizing the production of yeast metabolites

Hydrogels mimic natural environments due to their hydrated, polymeric networks which are beneficial for microorganism growth. The substantial water content maintains a consistently moist environment, and porous structure of hydrogel promotes efficient nutrient transfer and cell distribution, offering advantages over traditional liquid bioreactors. While their application in cell immobilization for bioconversion is well-known, their use as a solid-state fermentation matrix remains unexplored. This study is the first attempt to integrate gellan and amino acids to develop an innovative hydrogel bioreactor. The performance of this system was determined by cultivating Rhodosporidium sp. (MTCC 9733) as a model organism and evaluating its metabolite production. Further, gellan and amino acids concentration was optimized using one-factor-at-a-time and D-optimal response surface methodologies to produce β-carotene, lipid, and protein. Additionally, a comparison of productivity, yield, and process economics suggested that novel solid-state hydrogel fermentation approach outperformed classical submerged fermentation in YMB liquid media. Moreover, rheological properties of optimized hydrogel, conducted before and after yeast cultivation, revealed that this system possesses significant mechanical strength and structural integrity. Such attributes render the hydrogel suitable for utilization across multiple fermentation cycles. Hence, this study illustrates the potential of gellan-amino acid hydrogels as sustainable, efficient alternatives to conventional fermentation methods.

From waste to sustainable production: Experimental design and optimization of sustainable concrete using response surface methodology and life cycle assessment

This study focuses on a holistic approach to investigate the engineering properties (microstructural, mechanical, environmental, and economic) of sustainable concretes produced using recycled aggregate and supplementary cementitious material (SCM). Compressive strength tests was conducted on 24 sustainable concrete series for the mechanical properties. Statistical analyses were performed using the response surface methodology, and mathematical models were developed considering the strength values obtained. Developed model-based optimization solutions were applied to determine the mix proportions of the optimization series containing lower cement dosage and SCM with the same hardened concrete properties as the reference concrete series. Considering these mix proportions, life cycle assessments were performed and environmental and economic properties were compared. A comparison of Ref-6 and Opt-6 series reveals that the global warming potential (GWP), energy consumption (EC), and waste generation (WG) values are 422.4-330.9 kg CO2 eq, 1294-1044 MJ, and 1294-1222 kg, respectively. This situation resulted in a reduction of 21.7% in GWP values, 19.3% in EC values, and 5.6% in WG values. Similarly, the economic comparison of these series indicates that the total cost values are 81.9-75.7 €, respectively, resulting in 7.7% reduction. Finally, Scanning Electron Microscopy analyses were conducted to examine the microstructural properties. The use of fly ash at 10% improved the microstructure properties and increased the C-S-H gel formation. It is thought that the process of transition from these waste materials to sustainable production is of critical importance, especially in places that are heavily damaged after devastating earthquakes and where large amounts of waste materials are generated.

Environmental and Economic LCA Comparison of Flexural Strengthening Solutions for a Reinforced Concrete Beam

The construction sector is one of the largest creators and distributors of wealth, contributing to economic growth worldwide. However, this economic growth comes together with very high environmental impacts. Thus, rehabilitation solutions that can adapt the current building stock to today’s structural requirements are needed, increasing structural safety, while avoiding the production of demolition waste and the extraction of virgin raw materials, hence lowering the construction sector’s environmental impacts. Such rehabilitation solutions need to be environmentally and economically sound so that stakeholders can make informed decisions based on their needs and priorities. This paper presents a case study of an existing reinforced concrete beam, whose flexural resistance is increased using four alternative strengthening solutions: concrete jacketing, without and with increasing the cross-section size, and plate bonding, using either carbon fibre-reinforced polymer (CFRP) strips or steel plates. These solutions are studied via an environmental and economic cradle-to-gate life cycle assessment (LCA), resulting in a comprehensive comparison of their environmental and economic impacts, followed by a multicriteria and sensitivity analysis and eco-cost approach to determine the optimal solution. According to the criteria considered in the study, when environmental impacts are more valued, the concrete jacketing solution presents the best results and, when cost is dominant in the decision, the bonding of CFRP strips becomes the optimal solution.

The effectiveness of autonomous public transport systems in densely populated urban areas

This paper presents an in-depth analysis and comparison of technologies for autonomous transport systems, focusing on logistical considerations, economic factors, and overall outcomes. The study evaluates various scenarios, including manned and autonomous ground vehicles, as well as infrastructure solutions, to provide insights into their operational efficiency and economic viability.In the logistical comparison, findings indicate that autonomous and manned ground vehicles operate within similar logistical frameworks but offer different operational flexibilities. Autonomous systems demonstrate potential advantages in adaptability to changing passenger needs and risk reduction through sensor-based navigation. Additionally, deploying autonomous infrastructure solutions shows promising results in reducing cycle time (-43 % to ground manned/autonomous vehicles) and increasing technical speed (+57 % to ground manned/autonomous vehicles), especially in strained infrastructure environments.The economic comparison reveals challenges in assessing the cost-effectiveness of autonomous solutions due to a lack of pricing data. While the automation of public transport vehicles incurs higher capital (e.g. 33 % increase for autonomous buses vs manned) and operational expenditures (e.g. 60 % increase for autonomous buses vs manned), autonomous systems offer benefits such as continuous operation and reduced idle time. Investments in infrastructure solutions present opportunities to diversify traffic flow and enhance the overall transportation system.In conclusion, the autonomous transport system market requires increased transparency in pricing structures and technical maturity. Successful deployment depends on thorough demand studies and compatibility analyses with existing infrastructure. Innovative approaches like autonomous monorails or suspended Light Rail Transit (LRT) offer scalability, efficiency, and reduced environmental impact. Integrating predictive maintenance systems and advanced fleet management enhances reliability and service quality. Fostering transparency, embracing innovation, and implementing robust management systems are crucial for the successful integration of autonomous transport systems into urban environments.

Contributions to Incorporation of Non-Recyclable Plastics in Bituminous Mixtures

Over the past 50 years, global plastic production has surged exponentially. Around 40% of this plastic is used for packaging, most of which is single-use, while 20% is used in construction. Despite the vast quantities produced, only about 6% of discarded plastics are properly recycled, 10% are incinerated, and the majority are disposed of without proper management. With low recycling rates and some plastics being non-recyclable or with limited recycling cycles, it is important to explore new ways of reusing this waste as secondary raw materials. This study explores the potential of incorporating non-recyclable plastic waste into bituminous mixtures. The objective is to develop a sustainable solution for surface courses with similar or better performance than traditional bituminous mixtures by incorporating plastic waste using the dry method. A bituminous mixture containing 10% non-recyclable plastic was formulated and tested for water sensitivity, wheel tracking, and stiffness modulus. Additionally, environmental and economic comparisons were performed with a standard surface mixture. Results showed increased water resistance, high resistance to permanent deformation, reduced stiffness, lower susceptibility to frequency and temperature variations, and greater flexibility. These findings suggest that adding plastic not only enhances mechanical properties but also reduces costs, offering a sustainable alternative for non-recyclable plastics in road construction.

Economic evaluation of the Liverpool heart failure virtual ward model.

A virtual ward (VW) supports patients who would otherwise need hospitalisation by providing acute care, remote monitoring, investigations, and treatment at home. By March 2024 the VW programme had treated 10 950 patients across six speciality VWs, including heart failure (HF). This evaluation presents the economic assessment of the Liverpool HF VW. A comprehensive economic cost comparison model was developed by York Health Economics Consortium (University of York) to compare the costs of the VW to standard hospital inpatient care (SC). The model included direct VW costs and additional costs across the care pathway. Costs and resource use for 648 patients admitted to the HF VW were calculated for 30 days post discharge and total cohort costs were extrapolated to a full year. Primary outcomes included costs related to length of stay, readmissions, and NHS 111 contact. The total cost for the HF VW pathway, including set-up costs, was £467 524. This results in an incremental net cost benefit of £735 512 compared to the total SC cost of £1 203 036, indicating a substantial net cost benefit of £1 135 per patient per episode (PPPE). This advantage remains despite initial setup expenses and ongoing costs such as home visits, virtual consultations, point-of-care (POC) testing and home monitoring equipment. Our HF VW model offers a substantial net cost benefit, driven by reduced hospital stays, fewer emergency department visits, and lower readmission rates. The study highlights the importance of considering system-wide impacts and continuous monitoring of VWs as they develop.

Case Studies of Battery Energy Storage System Applications in the Brazilian Transmission System

This paper presents the preliminary results of studies aiming to use a battery energy storage system (BESS) in the Brazilian transmission system. The main objective of the BESS is to solve congestion problems caused mainly by the large increase in variable renewable generation in certain system areas. The studies were conducted based on actual forecasted system scenarios using a full representation of the electric grid available from the Brazilian system operator data base. In this work, only the steady-state modeling was considered as this may be the first stage in the assessment of a new technology. A qualitative economic comparison of the BESS application with other possible solutions to the congestion problems is also included.

Economic comparison of stocker cattle performance on winter wheat vs. summer-dormant tall fescue with nitrogen or interseeded alfalfa in the southern great plains.

Winter wheat (Triticum aestivum L.) is a significant forage source for livestock grazing in the Southern Great Plains (SGP). However, increasing input costs and changing climate conditions compel producers and researchers to search for alternative forage systems, such as cool-season perennials. Specifically, cool-season perennials with summer dormancy traits can survive droughts in the SGP. This paper aimed to determine the net returns of three different types of cool-season perennial summer-dormant tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] systems either with N fertilizer or interseeded with alfalfa (Medicago sativa L.) and the traditional graze-out annual winter wheat forage system. The data were from a 5-yr experiment conducted in south-central Oklahoma. Animal performance results indicated that the traditional graze-out winter annual wheat forage system provided more total gains at 434kg ha-1 than the three tall fescue variety systems at 326kg ha-1 (P = 0.006) due to more grazing days. Thus, the gross revenue estimated at a cost of gain of $1.60kg-1 gain for wheat at $694 ha-1 was greater than the average gross revenue of $521 ha-1 for the tall fescue systems. However, the average total cost for the perennial tall fescue systems ($374 ha-1) was less than the total cost ($594 ha-1) of the wheat system. Overall, the average net returns were similar for all grazing systems at about $145 ha-1.

Techno-economic study of gas turbines with hydrogen, ammonia, and their mixture fuels

Ammonia is a versatile energy carrier without carbon emissions that can be used for power generation. In this article, a techno-economic analysis has been done to predict the levelized cost of electricity production using gas turbines with clean fuel in Iran. In the technical discussion, the analysis of different scenarios of ammonia and hydrogen fuel composition ratio was done, and by keeping the turbine inlet temperature to the same gas turbine as the SGT5-2000E turbine, the output power in different fuel ratios is around 192.8–229.0 MW was variable and reached the maximum value in some proportions. Also, in the economic discussion, the effects of fuel cost and interest rate parameters were investigated, sensitivity analysis was performed on different combined ratios of ammonia and hydrogen in fuel, and an economic analysis of the ideal ratio was conducted. The price of ammonia fuel was calculated from 222 $/ton to 2000 $/ton, and the levelized cost of electricity production changed from 91.7 $/MWh to 673.4 $/MWh. Additionally, an economic comparison was made between the utilization of ammonia-hydrogen and natural gas fuels. This alternative fuel can be a promising way to produce power without carbon emissions and suitable storage for renewables.

Biomass-Driven Polygeneration Coupled to Power-to-X: An Energy and Economic Comparison Between On-Site Electric Vehicle Charging and Hydrogen Production

The power-to-X strategy for passenger car applications offers a viable solution for using the surplus electrical power from renewable energy sources instead of exporting it to the grid. The innovative system proposed in this study allocates surplus electrical power from a building-integrated biomass-based Combined Cooling Heating and Power (CCHP) system to on-site applications and evaluates the energetic and economic benefits. The system comprises two key components: a 50 kW electric vehicle (EV) charging station for EVs and a 50 kW alkaline electrolyzer system for on-site hydrogen production, which is later dispensed to fuel cell electric vehicles (FCEVs). The primary goal is to decrease the surplus of electricity exports while simultaneously encouraging sustainable transportation. The system’s economic viability is assessed through two scenarios of fuel (e.g., biomass) supply costs (e.g., with and without fuel market costs) and compared to the conventional approach of exporting the excess power. The key findings of this work include a substantial reduction in surplus electricity exports, with only 3.7% allocated for EV charging and 31.5% for hydrogen production. The simple payback period (SPB) is notably reduced, enhancing economic viability. Sensitivity analysis identifies the optimal hydrogen system, featuring a 120 kW electrolyzer and a 37 kg daily hydrogen demand. The results underscore the importance of prioritizing self-consumed energy over exports to the national grid, thereby supporting integrated renewable energy solutions that enhance local energy utilization and promote sustainable transportation initiatives.

Environmental and economic assessment of energy projects.

The energy industry has a significant impact on the scarce fossil hydrocarbon resources and on the environment. The burning of natural energy carriers by traditional energy facilities is one of the factors increasing the content of greenhouse gases in the atmosphere that entails serious climate changes. Evaluating the efficiency of energy enterprises and the implementation of energy projects requires an integrated approach that considers not only technical and economic aspects, but also the environmental impact. Such approach is especially important in the context of the energy transition and the implementation of circular economy principles. Despite the attention of scientists to the tasks of scientific, methodological, and practical determination of the economic efficiency and environmental consequences of energy projects, the issue of environmental and economic assessment remains relevant, in particular considering resource and environmental efficiency. The purpose of this study is to improve the methodological tools of environmental and economic assessment of energy projects. The authors propose an approach to the assessment of energy projects using an integral indicator. This indicator is calculated based on a system of specific indicators of the natural resource capacity and the environmental compatibility of energy production at the energy facility, considering the regional environmental conditions. The formed approach can be used for environmental and economic assessment and comparison of energy projects, fast-acting measures, and projects for the development of energy enterprises.

Towards maximum cost-effectiveness: multi-objective design optimisation of insulating glass flat-plate collectors

A significant challenge in the advancement of solar thermal heating systems lies in the unexplored techno-economic potential of insulating glass flat-plate collectors. These collectors are constructed in accordance with the specifications of standard insulating glass units and have emerged over the past decade as a promising design concept for enhancing the cost-effectiveness of solar thermal systems. However, substantial findings regarding the techno-economic viability of their production are still pending. The aim of this paper is to optimise insulating glass collector designs for solar district heating applications by identifying key design parameters that maximise cost-effectiveness. This study employed a five-stage methodology. It included thermo-hydraulic collector modelling using MATLAB/Simscape and the CARNOT Toolbox. The model was validated against experimental performance tests. A Latin hypercube computational design with 250,000 samples was set up to train supervised machine learning metamodels and perform a multi-objective optimisation using an elitist genetic algorithm. The study identified the argon concentration, collector length, and width as critical parameters influencing efficiency. Larger, thinner collectors demonstrated superior performance due to reduced convective losses and increased aperture-to-surface ratios. The optimisation revealed that the insulating glass collectors could achieve a 7.7 percentage point increase in efficiency, a 19.4 % reduction in material cost, and a 14.5 % decrease in weight compared to market-available flat-plate collectors. However, the direct economic comparison was not considered strong in evidence due to a lack of economic data from technology providers. The most cost-effective designs featured an argon concentration of 99 %, sealing thickness of 31.2 mm, and a glazing thickness of 4.1 mm, and 4.5 mm, while collector length and width varied more significantly. The research findings indicate the techno-economic potential of insulating glass collectors, demonstrating their ability to outperform conventional flat-plate collectors in terms of cost-effectiveness and efficiency. Future studies should focus on producing and testing larger modules and incorporating production costs to fully realise their potential for solar district heating applications. This study provides valuable guidelines for IGU designers and producers aiming to develop cost-effective and efficient solar thermal collectors for district heating systems.

Promoting Sustainability in the Automotive Industry: Economic Comparison of Dealer Sales Model and Agency Sales Model of Electric Vehicles in Slovakia

Electrification is becoming an increasingly important part of many industries. Electrification is a crucial area of interest in developing electric vehicles and charging infrastructure in the automotive industry. Research and innovation in the field of electric vehicles indicate positive trends. The rise in sales of electric vehicles represents a significant shift away from traditional fossil fuel-powered technologies to more sustainable and efficient alternatives. Electrification also brings with it new trends in sales models. The paper aims to identify recommendations for the practical adaptation of the importer of electric vehicles in the Slovak market based on the analysis of the financial and economic impacts of the sale of electric vehicles. This paper approaches two essential research topics. The first research topic focuses on the analysis of vehicle sales, specifically electric vehicles, and based on the analysis of existing sales, the paper will also outline the sales plan of the selected brand in the period 2023–2025. The second research topic focuses on changes in the business model for the sale of electric vehicles. One of the findings is that a specific indirect sales model for the automotive industry, i.e. selling vehicles through dealers, is used. In the long run, the new agency sales model standards should help correct many of the shortcomings of the current sales system. The effects on the profitability of sellers can be defined mainly by smaller financial costs caused by the cancellation of storage spaces, smaller credit indebtedness resulting from not creating warehouse stocks, and a greater focus on sales and additional services aimed at the end customer. Agency selling also allows the seller to get precious data about the customer and feedback directly to the manufacturer, which can serve as a valuable source of information for improving goods and services, which, in the long run, can lead to greater profitability for sellers. However, the Agency sales model is also coming to the fore. In this paper, the given types of business models are compared, their advantages and disadvantages are highlighted, and last but not least, the expected profits of the analysed company are calculated for both types of sales models. Keywords: agency sales model, business model, dealer sales model, economic comparison, electric vehicle

Computational analysis of wind tower-equipped sunken greenhouse for optimum microclimate control in hot arid regions

This research focuses on designing, computationally modeling, and assessing a novel sunken greenhouse equipped with wind towers to create an optimum microclimate capable of enhancing crop productivity and quality while minimizing energy consumption in hot arid climates that present challenges like extreme ambient temperatures and intense solar irradiation. Three innovative, energy-efficient, and cost-effective techniques were integrated into the proposed greenhouse design: (1) Wind tower-driven natural ventilation, (2) fully sunken greenhouse structure, and (3) direct evaporative cooling. The airflow dynamics, solar heat transfer, and the interaction of moist air within the greenhouse environment were investigated to analyze the system’s performance and optimize its design. The results showed efficient ventilation rates and great improvement in the greenhouse’s internal microclimate in terms of temperature and relative humidity. The average airflow velocity inside the greenhouse, measured at 1 m height, ranged from 0.11 to 0.69 m/s for nominal wind speeds of 1–6 m/s, while air changes per minute range is 0.28–1.7. Even under extreme ambient conditions (30–45 °C, 15–50 % humidity), the proposed greenhouse mostly maintained temperatures below 35 °C, reducing interior air temperatures by up to 11.7 °C from the ambient and increasing humidity by up to 57.1 %. The economic feasibility comparison of the proposed greenhouse to a conventional active-cooled greenhouse showed a remarkable 74.5 % reduction in the life cycle cost of the microclimate control technique.

Assessing the cost-effectiveness of replacing antimetabolites with mTOR inhibitors in heart transplant immunosuppression in China: a network meta-analysis-based economic evaluation.

Although several pharmacoeconomic studies have assessed the cost-effectiveness of maintenance immunosuppressive regimens for heart transplant recipients, economic comparisons between various combination drug therapies remain sparse. This study used an economic evaluation based on network meta-analysis to assess the cost-effectiveness of four immunosuppressive regimens for adult heart transplant recipients in China. We conducted a systematic search for clinical trials in PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Data, and VIP database. A validated Markov model was adapted to reflect the Chinese medical landscape. Four maintenance immunosuppression regimens were considered: tacrolimus/mycophenolate mofetil (TAC/MMF), cyclosporine/mycophenolate mofetil (CSA/MMF), everolimus/cyclosporine (EVL/CSA), and sirolimus/tacrolimus (SRL/TAC). The probabilities of health events were derived from a comprehensive literature review. Direct medical costs, adjusted for 2022 values, were from public documents and websites, while utilities for quality-adjusted life-years (QALYs) were taken from previous studies. Primary outcomes were mean lifetime cost, QALYs, and cost-effectiveness, with a willingness-to-pay (WTP) threshold set at three times China's GDP per capita in 2022. Sensitivity analyses were conducted to test the robustness of the results. The base case analysis identified TAC/MMF as the most cost-effective regimen, producing a mean of 6.31 QALYs per patient at a cost of Chinese Yuan (CNY) 534,182.89. Sensitivity analyses consistently reinforced TAC/MMF as the most cost-effective and robust choice. TAC/MMF is the most cost-effective maintenance immunosuppressive regimen for heart transplant recipients within the Chinese health system. The study findings are reinforced by sensitivity analyses, affirming their robustness amid various uncertainties.

Hydrogen vs. conventional sector-coupling residential energy systems: An economic and environmental comparison based on multi-objective design optimization

Planning residential energy systems faces economic, environmental, and technical challenges, necessitating cost-effective and environmentally friendly solutions. Hydrogen technologies in districts have recently gained interest. However, their economic and environmental potential relative to conventional technologies remains largely unexplored. Therefore, we quantitatively compared the impacts of designing hydrogen-based and conventional sector-coupling systems on total costs and CO2 emissions.We developed a multi-objective optimization model for the design and operation of generation and storage units, aiming to minimize total costs and CO2 emissions. We created three energy system configurations for an exemplary German district, each involving photovoltaics, heat storage, and batteries, while varying the main heat supplier. The first configuration includes a gas combined heat and power unit, the second features a heat pump, and the third incorporates a fuel cell, an electrolyzer, and hydrogen storage.Our comparison of the Pareto fronts revealed that the hydrogen system’s cost is 83% higher than the gas-based system and 33% higher than the heat-pump-based system. Environmentally, the hydrogen system emits 11% less than the gas-based system but 47% more than the heat-pump-based system. In conclusion, hydrogen units offer environmental benefits through improved photovoltaic utilization but perform poorly economically due to high investment and operating costs.

Economic validation and comparison of microbial tryptophan, erythritol and collagen production in an integrated sugarcane biorefinery

Low sugar prices present a significant challenge to the global sugarcane industry, prompting the exploration of diversification strategies for expanding product portfolios. Techno-economic analyses and environmental sustainability assessments were carried out to evaluate the microbial production of tryptophan, erythritol, and collagen from A-molasses in a biorefinery annexed to an existing sugarcane mill. Tryptophan production exhibited the highest profitability, with a minimum selling price (MSP) at 59.7 % of its current market price, although the achievable production volumes of tryptophan from one sugar mill would oversupply the global market. Due to the larger market size of for collagen the achievable production capacity in the collagen scenario would avoid market saturation, reducing the risk of oversupply and rendering it more economically viable. In contrast, erythritol production was marginally not profitable, with an MSP exceeding the current market price by 1 %, primarily attributed to high operational costs. All scenarios demonstrated relatively low greenhouse gas (GHG) emissions (ranging from 9.1 to 16.5 kg CO2eq/kg product), with tryptophan production emerging as the most environmentally favourable option due to minimal chemical and freshwater usage. When compared with literature-reported data on ethanol and short-chain fructooligosaccharides (scFOS), only collagen and ethanol production were deemed viable, based on their favourable profitability and contribution to the market.

Репрезентативность показателей и объективность оценок в компаративистике: экономика Российской империи второй половины XIX столетия в современных зарубежных исследованиях

The relevance of comparative studies of the level of industrial and economic development of the Russian Empire in the second half of the XIX century is determined by the fact that their results in some cases are used to substantiate theoretical ideas about the national characteristics of the Russian economy and society in comparison with the leading countries of Industrial Revolution. In economic literature, assertions about the “catastrophic” backwardness of Russia during this period are often encountered. Modern foreign historical-economic research allows for a more objective assessment of the gap between the level of industrial and economic development of the Russian Empire and the “advanced” states. However, the authors of these studies do not always succeed in consistently applying the principle of uniform criteria for comparing different economies. In particular, it is hardly justified: in some cases, to take into account, and in others, not to take into account the population and economic potential of territorial isolated peripheral regions of the respective economies. For example, the value of historical and economic comparisons is reduced by the confusion in research between the actual territory of the Russian Empire in the middle and second half of the XIX century, its territory within the conditional “borders of 1913” and the territory within “former USSR” borders. In this regard the article notes that conclusions drawn on the basis of fragmentary and arbitrarily interpreted information can’t be considered as fully correct. According to the author, in a comparative analysis of the economies-leaders of the Industrial Revolution, it is necessary to use assessment methods that take into account the population and indicators of economic development of peripheral territories were included in trade and financial exchanges with these economies, because this inclusion strongly spired the development of economies-leaders.

Thermodynamic and economic comparisons of supercritical water oxidation and gasification of oily sludge under hydrothermal flames

Dual-shell reactors using hydrothermal flames as internal heat source were proposed for supercritical water gasification (SCWG) and oxidation (SCWO) of oily sludge to achieve fast preheating and avoid corrosion, salt plugging, and overheating. The SCWG and SCWO systems with hydrogen-rich syngas and electricity outputs, respectively, were established and simulated using Aspen Plus 11. Simulation models were validated by comparing with experimental products and temperature profiles. The maximum exergy destruction coefficients of 28.01% and 24.31% appear in the combustion reactor for both the SCWG and SCWO systems, respectively, indicating the indirect preheating method with hydrothermal flame is critical to the energy efficiency. The increase of reaction temperature promotes hydrogen but inhibits methane formation in the SCWG, and more steam but less syngas is output at higher reaction temperatures. Although more steam and electricity outputs are present at higher reaction temperatures for the SCWO, more fuel input is required. Lower exergy efficiencies are obtained at higher reaction temperatures in both the SCWG and SCWO systems for more energy is output as low grade steam. Less fuel input is required for both the SCWG and SCWO systems at higher feed concentrations, and higher exergy efficiencies can be obtained. The net treatment cost for the SCWG and SCWO systems are 119.19 and 215.47 USD/t, respectively, indicating the SCWG is more economically competitive compared with the SCWO.

Biomass-to-Green Hydrogen: A Review of Techno-Economic-Enviro Assessment of Various Production Methods

H2 is considered a practical substitute for fossil fuels, especially for transportation by road and air, created either from fossil fuels or through the process of electrolysis of water. Research questions were included based on numerous research and the analysis of articles. The cost analysis of H2 processes, techno-economic hurdles in commercialization, and the economic comparison of various H2-production methods were the basis for the study of papers. The current research examines the different methods of thermochemical, biological, and electrochemical processes utilized in converting biomass into hydrogen. The benefits, constraints, and significant enhancements of every procedure are outlined. The examination assesses the cost of production, the level of technology readiness, and the potential for scalability. Thermochemical techniques, such as gasification and steam reforming, are effective at producing hydrogen. Steam gasification is perfect for moist and dry biomass in the absence of an oxidizing agent. Dark fermentation is more efficient for biological conversion because it requires less energy. Moreover, the electrochemical procedure is viable for biomass. Thermochemical treatment is significantly more advanced than biological or electrochemical treatment when it comes to scaling opportunities based on comparisons of current processes. The results of this research show that biomass–hydrogen processes have the potential for increasing H2 production, but further enhancements are needed to produce larger quantities for competitiveness.