Generation Facilities Research Articles

MONITORING SISTEM PROTEKSI KEBAKARAN AKTIF PADA PLTU ANGGREK 2 X 25 MW

The Anggrek Unit Steam Power Plant (PLTU) is a power generation facility whose construction began in 2007 and began operating in 2019 with a capacity of 2 x 25 MW. Since its inauguration, PLTU Anggrek has become one of the main sources of electricity distribution in Gorontalo Province, so the frequency of power outages in the area has now decreased significantly. The water supply system for fire fighting uses BSP pipes. In this research, the aim is to determine the active fire protection system. This research was carried out with a qualitative descriptive design with data collection: observation and interviews. The assessment of the results of existing suitability will be assessed using descriptive percentage calculations. The research results show that of the 7 variables discussed, the average value for the level of fulfillment is 98.57%. Based on the level of fire audit assessment that meets the requirements of Indonesian national standards and international standards, the results are in the Good criteria or have met the requirements.

Enhancing healthcare operations: a systematic literature review onapproaches for hospital facility layout planning.

The appropriate physical layout of hospital services can help resolve management problems by streamlining the work of medical teams, improving the flow of patients between specific areas and the medical support environment. Nevertheless, the academic literature lacks structured research into how the physical layout of hospitals might be improved. Our study aims to fill this research gap, providing information for researchers and professionals who intend to guide the hospital facility layout planning (HFLP) from the steps and prescribed approaches found in the literature. This study analyzes the current literature status and concerning approaches that support HFLP and identifies their strengths and weaknesses. The literature was classified using the following criteria: approaches for layout generation, approaches for layout evaluation and healthcare facility layout outcomes. The hospital facility layout outcomes achieved for each phase served as a basis for identifying a list of strengths and weaknesses for the hospital layout facility generation and evaluation approaches. Readers can refer to this paper to identify the approach that best fits the desired goal and the HFLP step. This is a contribution to current studies into HFLP, and it provides guidelines for selecting the approach to be utilized based on the desired outcome. The paper describes how to conduct an HFLP and lists the strengths and weaknesses of each approach. The research may be used as a strategy for determining which tool is most suited based on the practitioner's target purpose.

Facile Generation of Trideuteromethyl Radical from Alkylsilyl Peroxide and Subsequent Functionalization

AbstractCu‐ and Fe‐ catalyzed trideuteromethylation reactions using alkylsilyl peroxide as trideuteromethyl radical precursor are reported. The alkylsilyl peroxide was synthesized from acetone‐d6 in a three‐step sequence, and the reactions with various coupling partners afforded efficiently the corresponding N−CD3, O−CD3 and C−CD3 bond formation products. The radical heptadeuteriopropylation using alkylsilyl peroxide prepared from butyric acid‐d7 is also described.

Synergetic Effect of Heterojunction and Sulfur Vacancy on ZnIn2S4/CeO2 to Enhance the Photocatalytic Performance of 5‐Hydroxymethylfurfural into 2,5‐Diformylfuran

AbstractThe efficient separation of photocarriers and facile generation of superoxide radicals are crucial for enhancing the performance of photocatalysts in the selectively photo‐oxidizing 5‐hydroxymethylfurfural (HMF) into 2,5‐diformylfuran (DFF). Herein, a ZnIn2S4/CeO2 composite with S‐scheme heterojunction and sulfur vacancies (SV) is successfully developed through a one‐step hydrothermal method. The optimal catalyst (SV‐ZnIn2S4/CeO2) exhibits excellent catalytic activity with 100% conversion of HMF and 96.1% selectivity of DFF in 80 min under ambient conditions, the production rate of DFF is up to 952.6 µmol g−1 h−1. Intriguingly, the performance remains significant even when the concentration of HMF is increased from 8 to 100 mм. Experimental and theoretical investigations discover that the synergistic effect of S‐scheme heterojunction and sulfur vacancies contribute to the separation of photocarriers and the activation of oxygen, which facilitate the generation of superoxide radicals, thus boosting the catalytic oxidation reactions.

Advancing Nuclear Research and Education in Slovenia and EU: From Operating the TRIGA Reactor to Building a New Generation Facility

AbstractThe TRIGA Mark II research reactor at the Jožef Stefan Institute in Slovenia achieved first criticality in 1966. Since then, the reactor has been playing an important role in developing nuclear technology. The reactor has been mainly used for research, education of university students, training of operators of the Krško nuclear power plant (start of operation in 1983) and other nuclear specialists, isotope production and beam applications. The reactor is experiencing a high level of activity today, engaging in a diverse range of experiments and studies across reactor physics, environmental research, radiation hardness testing as well training and education. The future of nuclear technology in Slovenia is focused on new NPPs, while the research community is looking forward to a possible new nuclear reactor. The basic initiatives are at a very preliminary stage: the primary choice is dual-core pool-type reactor, with a zero-power core and a separate MW-size core, cooled and moderated with light water. Such a dual-core configuration is designed to meet the varied requirements of the European Union member states. Another option would be hosting one or more micro-reactors with electrical and/or heating power producing capability that could offer stronger support toward demonstration of prototype small modular reactors in prototype future electrical grids.

Capacity Factor Forecasting for Generation Facilities Based on Renewable Energy Sources in Decentralized Power Systems

Capacity Factor Forecasting for Generation Facilities Based on Renewable Energy Sources in Decentralized Power Systems

Investigating the impact of nanofluids and exergy metrics for integrated solar-biomass SCO2 power and desalination cycles

Several strategies have emerged for utilizing waste heat across diverse sectors. Yet, integrated systems that merge power generation with freshwater production, especially those leveraging renewable energy, remain relatively unexplored. Addressing this gap, a novel solar biomass-driven system is under development for power generation and desalination facilities. In the suggested system, rather than wasting the energy of a supercritical CO2 power cycle, a bottoming cycle is proposed to augment energy utilization factor (EUF). By integrating humidification-dehumidification, thermal vapor compression, and reverse osmosis (HDH-TVC-RO) with a multi-effect distillation (MED) unit, freshwater production rate is significantly enhanced. The outcomes reveal a freshwater output of 29.36 kg/s, a gained output ratio (GOR) of 17.36, and the EUF of 3.372. Various nanofluids have been assessed for the solar collector and due to superior total exergy efficiency and less corrosion effects, Cu- and carbon-based nanoparticles are recommended. Sensitivity analysis indicates that increasing the pressure ratio of compressors boosts the total GOR. Furthermore, adjustments to both the parameters of pressure of steam fed to HDH-TVC, and the compressor pressure ratio demonstrate a linear effect on EUF behaviour.

DEVELOPMENT TRENDS OF SOLAR POWER ENGINEERING BASED ON THE MATERIALS OF THE SCIENTIFIC AND PRACTICAL CONFERENCE «RENEWABLE ENERGY AND ENERGY EFFICIENCY IN THE 21

The main results of the reports at the "Solar Energy" section were considered and summarized, in particular, one of the areas of solar energy engineering - solar power generation. Specialists from Ukraine and the Republic of Uzbekistan took part in the work of the section in this field. A total of 32 reports were presented, focusing on topics such as the implementation of distributed generation facilities based on photovoltaic systems, improving the energy efficiency of solar power plants, etc. The reports demonstrated the primary trends to highlight the issues of building and operation of energy-efficient solar power plants in today's realities.

Interruption Cost Estimation for Value-Based Reliability Investment in Emerging Smart Grid Resources

Growing uncertainty in supply and demand in power systems causes significant challenges in maintaining supply reliability at affordable costs. Power grids are expected to undergo substantial transformations to address these challenges with upgrades and integration of emerging smart technologies that require significant investment costs. A value-based reliability assessment of these grid technologies is necessary to justify the worth of these investments. A key parameter required in such an assessment is the cost of power interruptions originating from transmission system failures. The interruption cost data available in published reports and past surveys relate to generation inadequacy since generation facilities comprise the most capital-intensive investment of an electric utility. Customer interruptions due to a lack of generation mainly occur due to generation failures during the peak demand period, whereas interruptions due to transmission component failures can occur at other periods with specific probabilities. This paper presents a methodology to estimate the cost of outages originating from transmission asset failures, which proposes a sector period model for each customer sector to obtain associated demand-normalized interruption costs. The proposed method can also be used to decide investment in grid resiliency enhancement against extreme weather that mainly impacts the grid network facilities.

Potentials of Green Hydrogen Production in P2G Systems Based on FPV Installations Deployed on Pit Lakes in Former Mining Sites by 2050 in Poland

Green hydrogen production is expected to play a major role in the context of the shift towards sustainable energy stipulated in the Fit for 55 package. Green hydrogen and its derivatives have the capacity to act as effective energy storage vectors, while fuel cell-powered vehicles will foster net-zero emission mobility. This study evaluates the potential of green hydrogen production in Power-to-Gas (P2G) systems operated in former mining sites where sand and gravel aggregate has been extracted from lakes and rivers under wet conditions (below the water table). The potential of hydrogen production was assessed for the selected administrative unit in Poland, the West Pomerania province. Attention is given to the legal and organisational aspects of operating mining companies to identify the sites suitable for the installation of floating photovoltaic facilities by 2050. The method relies on the use of GIS tools, which utilise geospatial data to identify potential sites for investments. Basing on the geospatial model and considering technical and organisational constraints, the schedule was developed, showing the potential availability of the site over time. Knowing the surface area of the water reservoir, the installed power of the floating photovoltaic plant, and the production capacity of the power generation facility and electrolysers, the capacity of hydrogen production in the P2G system can be evaluated. It appears that by 2050 it should be feasible to produce green fuel in the P2G system to support a fleet of city buses for two of the largest urban agglomerations in the West Pomerania province. Simulations revealed that with a water coverage ratio increase and the planned growth of green hydrogen generation, it should be feasible to produce fuel for net-zero emission urban mobility systems to power 200 buses by 2030, 550 buses by 2040, and 900 buses by 2050 (for the bus models Maxi (40 seats) and Mega (60 seats)). The results of the research can significantly contribute to the development of projects focused on the production of green hydrogen in a decentralised system. The disclosure of potential and available locations over time can be compared with competitive solutions in terms of spatial planning, environmental and societal impact, and the economics of the undertaking.

Investigation of operational settings, environmental conditions, and faults on the gas turbine performance

Abstract Gas turbine engines are complex mechanical marvels widely employed in diverse applications such as marine vessels, aircraft, power generation, and pumping facilities. However, their intricate nature renders them susceptible to numerous operational faults, significantly compromising their performance and leading to excessive emissions, consequently incurring stringent penalties from environmental regulatory bodies. Moreover, the deterioration of gas turbine performance is exacerbated by variations in working conditions based on operational settings and environmental conditions. Past studies have focused on certain working conditions that limit effectiveness in real-world applications where operational settings and environmental conditions vary during operations. The influence of these working conditions on the performance of gas turbines also needs to be assessed, as they can lead to different fault patterns resulting in unplanned maintenance, unnecessary maintenance costs, unsafe conditions and stringent penalties. This study uses the gas turbine simulation program to simulate a high-bypass turbofan engine inspired by Pratt & Whitney PW-4056, analysing the combined effects of operational settings and environmental conditions on engine performance while also incorporating simulations of common gas turbine faults like fouling and erosion in various locations and severities along the gas path. The model’s accuracy is confirmed by low mean absolute percentage errors of 0.004% of thrust at the cycle reference point and 0.15% and 0.28% at 2 km and 7 km altitudes, respectively, demonstrating the model’s robustness across varying operational scenarios. In conclusion, this research highlights the significant effects of operational settings and environmental factors on gas turbine performance, particularly impacting specific fuel consumption and thrust. The study reveals that operational settings and environmental factors significantly impact fuel consumption and thrust. Specifically, compressor fouling and low-pressure turbine erosion increase nitrogen oxide (NOx) emissions by 4.5% and 11.1%, while fouling of nozzle guide vanes and high-pressure turbine erosion raise unburned hydrocarbon by 10.0% and 20.2%, and carbon monoxide (CO) by 3.2% and 5.2%, respectively, compared to a healthy engine. These insights highlight the importance of component-specific degradation in influencing gas turbine performance and emissions.

Investigation into “hair” inclusions in large-sized KDP crystals grown by traditional method

Potassium dihydrogen phosphate (KDP) crystals are widely used in high-energy laser facilities for harmonic generation. An important defect observed in KDP crystals, known as "hair" inclusions in large-size crystals grown by traditional methods, was investigated using ultra-microscopy. Most of the "hair" inclusions within the crystals have a straight chain structure, while only a few displays a curved formation. The "hair" inclusions consist of multiple liquid inclusions and exhibit a chain-like structure with quasi-periodic features. The size of these liquid inclusions varies, ranging from 17.54 to 56.90 μm, and show a chain density between 0.90 mm−1 and 20.77 mm−1. The angles of the "hair" inclusion orientations about the c-axis range from 30° to 79°, corresponding to the dislocations in KDP crystals. Furthermore, the study examined the impact of "hair" inclusions on the transmittance of the crystals. This investigation aims to enhance the understanding of “hair” inclusions in traditionally grown KDP crystals and attempts to clarify the factors leading to the formation of these inclusions. It also offers a theoretical and experimental basis for reducing these inclusions in KDP crystals.

Benefits of In Situ Foamed and Printed Porous Scaffolds in Wound Healing.

Macroporous hydrogels have shown significant promise in biomedical applications, particularly regenerative medicine, due to their enhanced nutrient and waste permeability, improved cell permissibility, and minimal immunogenicity. However, traditional methods of generating porous hydrogels require secondary post-processing steps or harmful reagents making simultaneous fabrication with bioactive factors and cells impossible. Therefore, a handheld printer is engineered for facile and continuous generation and deposition of hydrogel foams directly within the skin defect to form defect-specific macroporous scaffolds. Within the handheld system, a temperature-controlled microfluidic homogenizer is coupled with miniaturized liquid and air pumps to mix sterile air with gelatin methacryloyl (GelMA) at the desired ratio. An integrated photocrosslinking unit is then utilized to crosslink the printed foam in situ to form scaffolds with controlled porosity. The system is optimized to form reliable and uniform GelMA foams. The resulting foam scaffolds demonstrate mechanical properties with excellent flexibility making them suitable for wound healing applications. The results of in vitro cell culture on the scaffolds demonstrate significantly increased cellular activity compared to the solid hydrogel. The in vivo printed foam scaffolds enhanced the rate and quality of wound healing in mice with full-thickness wound without the use of biological materials.

Features of planning and managing power flows in distribution grids of megalopolises

The study examines the root causes of disruptions of normal operation of power distribution grids in large cities and metropolitan areas. The existing principles of scheduling and maintaining power flows in power distribution grids as well as ways of ensuring the reliability of their operation are analyzed. The integration of fuel-fired distributed generation facilities and renewable generation plants into distribution networks is shown to affect the ability to ensure transient stability during emergency disturbances. We establish evaluation criteria and provide upward margin values to determine the feasibility of the planned power flows. The study reveals general patterns in the calculation of the upward margin for power distribution grids of large cities and metropolitan areas. Test power flow analysis is performed for a real-world segment of a metropolitan area power distribution grid to identify possible overloads of power grid equipment and develop and implement a list of measures for the power flow to achieve the feasible region. The developed approach makes it possible to minimize load shedding or rule out load shedding altogether, ensuring reliable power supply to consumers in large cities and metropolitan areas in the event of an unexpected load growth.

Multi-Modal Machine Learning to Predict the Energy Discharge Levels from a Multi-Cell Mechanical Draft Cooling Tower

An artificial neural network was developed to augment the accuracy of a physically based computer model in relating heat discharge to visible plume volume of a 12-cell mechanical draft cooling tower. In a previous study, Savannah River National Laboratory developed a 1D model to capture the average power plant discharge levels via analysis of a series of visual images but was unable to accurately predict individual cases, resulting in an overall average error of about 5%, but individual comparisons resulted in an R2 of 0.36. Three optimization algorithms were applied to better fit the entrainment coefficients, and the artificial neural network model was applied to 289 cases of a 12-cell mechanical draft cooling tower power generation facility. Two artificial neural networks configurations consisted of 10 and 47 nodes that used as input readily available plant data, observed cooling tower plume conditions, observed operational conditions, local and regional weather, and the predicted plume volume from the physical model; the individual predictions’ accuracy improved to R2>0.95. This article concludes the sensitivities for the 1D model and additional actions to progress this field of study as well as applications for cooling tower monitoring. This strategy demonstrated an encouraging first step towards using multi-modal artificial neural network machine learning technology for information fusion to estimate power levels from external observations.

Public-public partnerships : A twist on the traditional publicprivate partnership that works for your airport

As airport operators, the provision of chilled water and back-up power generation is a necessary element of our utility infrastructure. This paper outlines the benefits and pitfalls related to outsourcing this increasingly critical infrastructure to the local power company and describes the case of Orlando International Airport (MCO), which formed a public-public partnership with Orlando Utilities Commission (OUC). Over the course of a multiyear negotiation, we engaged OUC to take on operating the chilled water plant and the back-up generation facility for the airport’s new Terminal C. Throughout the negotiation, we addressed many challenges. The aim of this paper is to familiarise the airport operator with the transaction and some of the key issues we faced and resolved at MCO.

Synthesis of Modified Nucleosides Using 4'-Carbon Radicals

Nucleosides with a substituent at the 4'-position have received much attention as antiviral drugs and as raw materials for oligonucleotide therapeutics. 4'-Modified nucleosides are generally synthesized using ionic reactions through the introduction of electrophilic or nucleophilic substituents at the 4'-position. However, their synthetic methods have some drawbacks; e.g., (i) it is difficult to control stereoselectivity at the 4'-position; (ii) complex protection-deprotection processes are required; (iii) the range of electrophiles and nucleophiles is limited. With this background, we considered that a carbon radical generated at the 4'-position would be a useful intermediate for the synthesis of 4'-modified nucleosides. In this review, two novel methods for the generation of 4'-carbon radicals are summarized. The first utilizes radical deformylation involving β-fragmentation of a hydroxymethyl group at the 4'-position. The other utilizes radical decarboxylation and 1,5-hydrogen atom transfer (1,5-HAT), which enables the generation of 4'-carbon radicals while retaining the hydroxymethyl group at the 4'-position. These methods enable the rapid and facile generation of 4'-carbon radicals and provide various 4'-modified nucleosides including 2',4'-bridged structures.

Elemental composition of post-wildfire biomass ashes and partly burned woody species in Bohemian Switzerland National Park, Czech Republic.

The study explored the post-wildfire elemental composition of parts (wood, bark, branch, cone, trunk, litter, twig, needle, sward, fallow, sapling, etc.) and by-products (biomass ashes, partly burnt parts, and char) of different woody species in the Bohemian Switzerland National Park, Czech Republic, and considered their effects on soils. Multi-elemental analysis of the fire by-products of the woody species was determined with inductively coupled plasma-optical emission spectrometry and mass spectrometry and compared with control biomass samples unaffected by wildfire. Most fire by-products were slightly alkaline, with acidic ashes obtained from blueberry wood. The by-products of the wildfire were characterized by varied total contents of macro (P, Ca, K, Mg, and S), micro (Na, Mn, Fe, Cu, and Zn), and other elements (B, Co, Mo, and V) vital to soil fertility and plant growth. The mean content of macro elements in the biomass ashes was up to 4.16 P, 23.5 Ca, 2.48Mg, 63K, and 5.57 S g kg-1. These values were comparatively lower than published data for ashes obtained under optimized conditions, e.g., those combusted in power generation facilities. Conversely, partly burnt parts-an indication of incomplete combustion-had higher 9.22 P, 79 Ca, and 5.99Mggkg-1 contents in spruce needles than in biomass ashes and the control. Variations in woody species and anthropogenic activities in areas of wildfires produced varied As, Cd, Cr, Ni, and Pb contents above EU fertilizer regulation. Caution in applying biomass ashes from wildfires on fields is required due to risk/toxic elements input from anthropogenic activities. Wildfire effects on the elemental composition of woody species can provide information on plant parts most suitable for biomass ashes for soil and ecosystem safety.

Plant-wide modeling and techno-economic optimization of a low-pressure microwave-assisted ammonia synthesis process with adsorption separation

Ammonia production has traditionally been done by using the Haber-Bosch process, that operates at extremely high pressure (200–300 bar), has a large carbon footprint, and requires significant energy. For ammonia to be used as a hydrogen carrier, it is desired that it is produced by using modular technologies under benign conditions, yet the economics remain commercially viable. This paper investigates a novel technology for ammonia synthesis by using a microwave-assisted low-pressure reactor. Microwave reactors are compact and can be readily modularized and started/shutdown thus making them ideal to be integrated with the electric grid or with regional/local renewable-based electric generation facilities. For separation of unreacted reactants from the product ammonia, if the traditional condensation separation technology used in the high-pressure Haber-Bosch process is used, then the separation process needs to be operated under cryogenic condition thus adversely affecting the economics. A solid sorbent based separation technology is investigated in this paper. A kinetic model for the microwave-catalytic synthesis process is used. An isotherm model is developed for MgCl2–Si adsorbent and used for modeling the dynamic adsorption-desorption cycle. A plant-wide model with heat and mass integration is developed. An economic model is developed and used for economic optimization by using an equation-oriented approach. Since the adsorption-desorption process is dynamic, for techno-economic optimization, a reduced order model for the key performance measures of the adsorption-desorption process as a function of its input and decision variable is developed under cyclic steady-state conditions. For the optimized MW-assisted process, the levelized cost of ammonia is $772/mt as opposed to $808/mt for the conventional Haber-Bosch process for a hydrogen price of $2.07/kg. The MW-assisted process is found to be economically viable in the US market if the hydrogen price is below $4/kg.

Devising an integrated methodology for energy safety assessment at an industrial power-generating enterprise

This paper’s research object is a process of estimating the level of energy safety at an industrial enterprise within an electricity-power system at a microeconomic level. The task to estimate the energy safety of an industrial enterprise was solved on the basis of a combined method for the continuous monitoring of threats under an automated mode to the hour, in order to make management decisions related to reducing the influence of threats to energy safety. Analysis of known methods for investigating the state of energy safety was performed, which revealed the lack of continuous control over the dynamic state of research objects, as well as the complexity in objectivity when giving exact and reliable primary information to calculate indicators-indexes. It has been shown that the use of the combined approach could underlie the development of methodology for estimating the energy safety of industrial power-generating enterprise. Such approach involves comprehensive combination of logical methods when implementing continuous monitoring of technological parameters at generation, transmission, distribution, and energy consumption facilities. The process of choosing the objects of research and criteria for describing their properties and functions has been substantiated, in order to build the system of indicators-indexes when estimating the level of enterprise energy safety. It has been shown that a computation algorithm makes it possible to monitor the dynamics of changes in indicators and take a management decision to eliminate energy safety threats, which leads to a reduction in economic losses in the amount exceeding USD 150,000. Practical significance of the current research relates to the fact that the results could be used by enterprises (public authorities) for determining obstacles on a way to reducing the consumption of power resources and devising a set of organizational-economic measures