Steam Plant Research Articles

A Review of the Geothermal Potential Hot Spots in Iraq Using Geophysics Methods

This review introduces the concept of geothermal energy and the technologies used to harvest this sustainable and clean source. Geothermal systems were explained in details in the review. They were classified into two major types, steam cycle and binary cycle. The steam cycle is always used at higher enthalpy, and a binary cycle is used at low enthalpy. The power generation methods used to produce geothermal power from geothermal resources, typically, comprises of well production, injection and steam and gas separators, heat exchangers, preheaters, turbines and condenser. The steam cycle type allows the water to evaporate and the steam will be separated from brine solution and expanded in a turbine, generally the salty water will have discarded out of system, or it is flashed again at lower system part. Power generation methods were divided into single Flash Steam Plant, Double Flash Steam Plant, and Dry Steam Plant. The components of the geothermal power plant were elucidated, namely, feed pump, heat exchanger, preheater, evaporator, turbine, and condenser. After surveying the geothermal energy worldwide briefly, the Iraqi geothermal energy was introduced. Thermal gradient in Iraqi tectonic zone was analyzed. There is a very limited available literature on Iraq geothermal. However, we were able to analyze the geothermal temperature gradient in Iraq by dividing it into two regions; the northern Iraq, and the southern Iraq. Our analysis shows that Iraq is a poor zone for geothermal with no significant hot spots all over the country. However, low temperature applications can be invested using the exhausted petroleum wells.

Solar-powered PCC: An upfront levy for sustainable carbon capture

To solarize the carbon capture industry and completely move away from the power plant (PP) steam cycle, a novel concept for solar-powered post-combustion carbon capture (SP-PCC) is proposed. In this configuration, solvent regeneration directly occurs in a new design called a “solar stripper” (So-St) network, sized and designed to replace the conventional desorption unit of the PCC. This study evaluates the economic footprint of SP-PCC technology in comparison withconventional PCC where the steam is totally bled from the PP steam cycle, and solar-assisted PCC (SA-PCC) where a portion of the steam is produced in a solar collector field (SCF) to contribute towards the reboiler duty in the PCC. The CAPEX &OPEX, and the levelized cost of electricity (LCOE) are calculated for a 660 MWe coal-fired PP case-study located in Sydney, Australia. For the fully solar-driven process as in the SP-PCC case, the LCOE is 57.8% and 45.9% higher than the PCC and SA-PCC counterparts, respectively. The high LCOE for SP-PCC is attributed to the 100% solar contribution for the thermal duty demand. Under a similar 100% solar energy contribution for the SA-PCC case, the LCOE is more than five folds greater than the SP-PCC counterpart. Therefore, to fully solarize a carbon capture process, particularly in heavy industries where steam production is not part of normal routine, this novel SP-PCC method would be the best technology option. Comprehensive analyses of economic parameters reveal potential areas for LCOE reductions. Future work should explore ways to capitalize on solvent screening and process innovations to unlock the full potential of the SP-PCC technology.

Performance assessment of a novel medical-waste-to-energy design based on plasma gasification and integrated with a municipal solid waste incineration plant

A novel medical-waste-to-energy design combining plasma gasification (treating medical waste) and municipal solid waste (MSW) incineration has been developed. In the integrated system, the syngas generated by the plasma gasification of medical waste is first burned and drives the gas turbine for power generation, subsequently, the gas turbine exhaust is taken to heat the live steam and feedwater of the MSW incineration plant, improving the power cycle of the incineration plant. Consequently, medical waste can be converted into electricity efficiently in the meantime of harmless management. The hybrid design was investigated by multiple approaches including energy analysis, exergy analysis, and economic analysis. It is found that the energy efficiency and exergy efficiency of medical-waste-to-electricity can reach up to 37.83% and 34.91% with a net total power of 4.24 MW yielded from medical waste, while the net power generated from MSW is considered fixed. Besides, the proposed medical-waste-to-electricity project has a short dynamic payback period of 3.75 years and the relative net present value can achieve 45,239.90 k$. These results demonstrate that the novel concept is efficient, feasible, and advantageous, which is promising to be implemented in the field of waste-to-energy.

Development of a novel power generation system based on the co-combustion of agriculture biomass and sludge integrated with solar-aided sludge drying

Based on the evolution of conventional sludge drying methods, a novel co-combustion power generation system integrated with solar-aided sludge drying has been developed and evaluated for advancing environmentally friendly renewable energy power generation technologies. The integration is achieved by injecting the heat collected from sunlight by parabolic trough collectors into the sludge dryer through the feedwater. In the synthetic configuration, the extraction steam of biomass-fired power plant is saved and more power output is produced compared with conventional sludge drying methods. The performance of the proposed scheme was thermodynamically and economically assessed. In addition, the performance of the new design under different co-firing proportion, sludge moisture and solar irradiation was discussed. The results indicated that the additional power output can reach 2.13 MW at the design condition while the biomass consumption is fixed. Throughout the whole year, 9640.03 MWh additional electricity can be generated with 94,608 tons wet sludge disposed. Besides, the levelized cost of electricity of the new power is 0.0834 $/kWh, the dynamic payback period is 3.73 years and the net present value of 34806.00 k$ is achievable due to the incorporation. Therefore, the proposed design is feasible and profitable, providing fresh insights into renewable energy comprehensive utilization.

Integration of MHD System to The Gas Turbine and The Steam Turbine Power Plant: A Brief Review

Electrical energy generation is essential for the survival of the modern society. Fossil fuels are limited and create pollution. Also the conventional power generation systems using fossil fuel have lesser efficiency due to higher amount of losses in different sections of the plants. The Magnetohydrodynamic (MHD) is found as a nonconventional energy generation system which has the capability to enhance the thermal power plant efficiency significantly. The MHD is a direct energy conversion system that describes the interactions of a magnetic field and an electrically conductive fluid to produce electrical power. The system is simple and it avoids the difficulty of choosing a rotating turbine or engine and massive number of complex calculations. The high temperature tolerable materials can be used in the system due to the exponential development of material science. In MHD system, energy of plasma or ionized gas is directly converted into electric power. The conversion process of the system is based on the principle of Faraday’s Laws of electromagnetic induction and fluid dynamics. The MHD generator uses hot conductive ionized gas or plasma as the moving conductor whereas in the mechanical dynamo, in contrast, uses the motion of mechanical devices to accomplish this. Seeding materials such as potassium carbonate, potassium sulphates are used to enhance the conductivity of the ionized gas. The focus of the present study is to investigate alternative methods through which an MHD power generator can be coupled to the existing gas turbine and steam plants. In doing so, the thermal cycle efficiency of these conventional plants can be improved. A case study is also presented to calculate the power output and efficiency in a simple way.

Evaluating the Technical and Economic Feasibility of Adding a Power Recovery System to the Steam Condenser of a Lignite Coal-Fired Power Plant

Steam is the typical working fluid to drive turbo-generators in coal-fired power plants. It is an effective working fluid, but some of its energy is extracted in an unusable form when condensed. A Power Recovery Cycle (PRC) using a more volatile Secondary Working Fluid (SWF) added to the steam cycle could improve energy efficiency. PRCs have been applied to the flue gas and for combined cycle systems but not to traditional plant steam cycles. This paper details an analysis of adding a steam cycle PRC to a 500 MW lignite coal-fired power plant. A validated model of the plant was developed and PRCs using the three most attractive SWFs, benzene, methanol and hydrazine, were then added to the model. Adding a benzene, methanol, or hydrazine steam cycle PRC will produce an additional 59, 34, and 49 MW, respectively. An AACE Class 4 factored broad capital cost estimate and comparable operating costs and revenue estimates were developed to evaluate PRC feasibility. The benzene, methanol, and hydrazine processes had 2019 Net Present Values (NPVs) @12% of -$32, -$59, and +$35 million ± 40%, respectively. Thus, a PRC may be profitable at current or modest increases to U.S. Upper Midwest electricity prices of around $0.0667/kWh.

Selection of the Design of a Contact Condenser of a Gas-Steam Plant with Steam Injection into the Combustion Chamber

Due to the importance of the problems of implementing energy-saving technologies in modern conditions, one of the promising areas is the use of gas turbines for combined heat and power generation. One of the areas of effective development and technical re-equipment is the widespread use of highly economical combined steam and gas plants and gas turbines. The operation of the gas turbine unit “Aquarius” SE NPCG “Zorya-Mashproekt” with the injection of steam into the combustion chamber, which operates on the advanced cycle A-STIG and has in its circuit equipment for water regeneration, condensed from a vapor-gas mixture is considered. For condensation of steam from the vapor-gas mixture, a contact condenser-gas cooler is used, which is a mixing heat exchanger of complex design. The efficiency of heat transfer is determined by the design of the nozzle, namely, the developed heat transfer surface, small hydraulic supports, high heat transfer coefficients. An important aspect is the overall dimensions, which must be within certain limits. In the work it is offered to execute a design of the condenser in the form of a packed column. Different types of nozzles are considered to choose the best option. As a result of thermal design calculation of the contact capacitor, it is proposed to use Rashiga rings (15152) as a nozzle, which provide the lowest height of the nozzle at the required diameter of the device.

The Development of A Reliability Evaluation Application for Power Plant Steam Turbine Vibrations to Predict Its Failure

A steam turbine is the most critical component in a thermal power plant. Due to its crucial function, it should be maintained to be able to operate without failure. This paper aims to develop an application that can be used to analyze the reliability and synchronization of vibrations in a single evaluation through the application. The application is helpful to decide the proper time the maintenance should be performed in order to provide a better maintenance strategy. In this paper, the application was used to make an ease in evaluating the reliability and vibration of a 670 MW power plant steam turbine. The reliability was analyzed by qualitative and quantitative methods. The vibration evaluation using Fast Fourier Transform (FFT) was done by diagnosing the failure symptoms from vibration spectrum. The analysis of synchronization of vibrations conducted by comparing the vibration frequency and the natural frequency of the system which can be calculated easily using the application. The algorithm program of both evaluations was built using GNU Octave software to make a friendly user interface. From the evaluation result, the most critical components of the steam turbine are coupling, labyrinth seals, bearing, diaphragm, turbine control valve, and turbine stop valve. The maintenance interval based on the expected reliability of 90% produces the highest reliability improvement. Based on the vibration analysis, there is no failure symptoms detected in the turbine bearings. Furthermore, the dominant frequencies of vibration are distant from the natural frequency. Therefore, the steam turbine condition is acceptable to operate.

Exergetic sustainability analysis of municipal solid waste treatment systems: A systematic critical review

The growing volume of municipal solid waste (MSW) generated worldwide often undergoes open dumping, landfilling, or uncontrolled burning, releasing massive pollutants and pathogens into the soil, water, and air. On the other hand, MSW can be used as a valuable feedstock in biological and thermochemical conversion processes to produce bioenergy carriers, biofuels, and biochemicals in line with the United Nations’ Sustainable Development Goals (SDGs). Valorizing MSW using advanced technologies is highly energy-intensive and chemical-consuming. Therefore, robust and holistic sustainability assessment tools should be considered in the design, construction, and operation phases of MSW treatment technologies. Exergy-based methods are promising tools for achieving SDGs due to their capability to locate, quantify, and comprehend the thermodynamic inefficiencies, cost losses, and environmental impacts of waste treatment systems. Therefore, the present review paper aims to comprehensively summarize and critically discuss the use of exergetic indicators for the sustainability assessment of MSW treatment systems. Generally, consolidating thermochemical processes (mainly incineration and gasification) with material recycling methods (plastic waste recovery), heat and power plants (steam turbine cycle and organic Rankine cycle), modern power technologies (fuel cells), and carbon capture and sequestration processes could improve the exergetic performance of MSW treatment systems. Typically, the overall exergy efficiency values of integrated MSW treatment systems based on the incineration and gasification processes were found to be in the ranges of 17–40% and 22–56%, respectively. The syngas production through the plasma gasification process could be a highly favorable waste disposal technique due to its low residues and rapid conversion rate; however, it suffers from relatively low exergy efficiency resulting from its high torch power consumption. The overall exergy efficiency values of integrated anaerobic digestion-based MSW processing systems (34–73%) were generally higher than those based on the thermochemical processes. Exergy destruction and exergy efficiency were the most popular exergetic indicators used for decision-making in most published works. However, exergoeconomic and exergoenvironmental indices have rarely been used in the published literature to make decisions on the sustainability of waste treatment pathways. Future studies need to focus on developing and realizing integrated waste biorefinery systems using advanced exergy, exergoeconomic, and exergoenvironmental methods.

Microstructure and mechanical properties of friction stir welded Haynes 282

Advanced ultra-supercritical (A-USC) steam plants are designed to operate at high temperatures and pressures due to the necessity for higher operational efficiency. The extreme operating conditions of A-USC requires the deployment of precipitation strengthened Ni-base alloys that exhibit elevated temperature strength and good fabricability. Fusion welding of precipitation strengthened nickel alloys lead to solidification cracking in fusion zone and/or liquation cracking in heat affected zone. Therefore, an alternative non-melting welding technique is a necessity to efficiently join nickel alloys. In the current study, friction stir welding, a solid-state joining technique was implemented on a precipitation strengthened nickel-based superalloy, Haynes 282. Detailed microstructural and mechanical properties characterization was carried out. The processed region exhibited wrought, fine-grained microstructure, absence of weld defects such as voids and cracks and absence of elemental segregation. Both hardness and cross-weld tensile tests demonstrated that the weld region was stronger than the base material. And the cross-weld tensile samples failed in the base material. Based on joint efficiency analysis, friction stir welded Haynes 282 outperformed fusion welds.

Energy, Exergy-Based and Emergy-Based Analysis of Integrated Solar PTC with a Combined Cycle Power Plant

Solar energy is one of the most promising strategies to reduce energy consumption and emissions pollutions. In this paper, integrating a combined cycle power plant with a Solar Parabolic Trough Collector (PTC) is evaluated and investigated. In this regard, Qom Combined Cycle Power Plant is considered a real case study in Qom city. Energy, Exergy, Exergoeconomic, Exergoenvironment, Emergoeconomic, and Emergoenvironemntal Analysis as (6E) Analysis have been performed to understand the base plant's integration better. Environmental impacts have been calculated by Life Cycle Assessment (LCA) in Sima Pro Software. Also, computer code has been developed for 6E analysis of base and integrated power plants. Validation of thermodynamic simulation has been examined with Thermoflex Software and plant data. Energy analysis results show the power output of the steam plant and overall energy efficiency is increased to 7.14% and 4.44 % rather than the base case without adding additional fossil fuel. It shows the power generation and energy efficiency are increased significantly by adding PTC. Also, the overall exergy destruction and the total exergy cost rates are raised to 7 % and 11.27 %. In addition, overall environmental impacts, overall emergoeconomic, and overall emergoenvironmental values are increased to 1.67%, 6.2%, and 15.4%, respectively. However, the overall environmental impacts per net power are decreased.

Theoretical assessment of energy recovery from Beekeeping waste (Slumgum)

An evaluation of the energy potential of organic waste called “slumgum,” generated in the bee-wax industry, is developed. The main objective is to determine whether this waste can be used as fuel to generate the steam required in the plant, considering its combustion in a fluidized bed boiler. Currently, there are no studies in the literature associated with the use of slumgum for energy purposes; only its use for agricultural purposes is studied, thus highlighting the novelty of the present research. The slumgum's main physical–chemical and energy properties are determined, complementing the information available in the literature and mathematical correlations, obtaining a higher heating value of 17,076 MJ/kg in the dry base. An energy balance was made in the boiler, considering a bubbling fluidized bed system's operating conditions. Results show that for typical temperature values in the hearth of 850 °C and excess air of 20%, only 25% of the heat released in combustion is used to generate steam; the rest is lost as sensible heat in the exhaust gases. The plant's steam demand could be fully satisfied using the sensible gases heat, feeding 1.778 kg of slumgum of 8.000 kg produced during the all season, indicating that 77% of the feedstock remain as energy reserve. The proposed process's energy-ecologic-efficiency is 0,8; the economic savings obtained by fuel replacement, taking natural gas as a reference, corresponds to 716 USD per season.

Matrix method to solve inverse problem of heat transfer in heat exchangers with phase transition in heat carriers

The transition to environmentally friendly and resource-saving energy, efficient use of natural resources and energy performance are the key priorities of the state energy policy of the Russian Federation. Maximum use of heat combustion of fuel and simultaneously production of condensate water of the combustion products of natural gas is one of the directions of energy saving policy. Despite many scientific papers on the issues of utilization of flue gas heat, condensation heat exchangers are not used in most gas boiler houses, energy power providers and thermal power plants in this country. And there are several reasons to explain this fact due to the lack of universal methods to calculate and design condensation-type heat exchangers. Thus, the development of new methods to simulate multithreaded heat exchangers considering the phase transition in heat carriers is an urgent task of power engineering and industry sectors. Matrix models of heat transfer based on mass and energy balance equations are applied to solve the inverse problem of heat transfer in heat exchangers, considering the phase transition in heat carriers. A method to calculate and select the designs of multi-threaded heat exchangers, considering the phase transition in heat carriers, has been developed. The author suggests a numerical solution to choose the design of a contact economizer of a heat power plant steam boiler used for heat recovery of flue gases to illustrate the effectiveness of the proposed method. The proposed method to solve the inverse problem of heat transfer provides the possibility to identify simultaneously the most acceptable values of the parameters of heat carriers and design characteristics of heat exchangers for various purposes.

Absolute finite differences based variable forgetting factor RLS algorithm

Adaptive signal processing requires an efficient non-stationarity detector. Most of the known non-stationarity detection algorithms are based on residual statistics. The study proposes a novel non-stationarity detection algorithm based on finite differences analysis of the processed signal. It also includes a suitable procedure for the forgetting factor design in the adaptation process. The performance of the proposed algorithm is experimentally compared with other known algorithms with regard to slow changes in signal stationarity as well as the influence of free coefficient selection on the quality of estimation. The developed algorithm exhibits the ability to effectively track both slow and abrupt changes in signal stationarity, with a small steady-state error. The coefficients that need to be set during the application of this algorithm are given intuitive physical meaning. Simulations show good resistance to low signal-to-noise ratio and abrupt changes in noise variance. The results also demonstrate estimation performance relative to the water level signal from a thermal power plant steam separator.

A novel design protocol for solar-powered carbon capture

To solarize the carbon capture industry and move away from the power plant steam cycle, this paper presents a new methodology for solar-powered post-combustion carbon capture (SP-PCC). It comprises a rigorous thermodynamic model for a “solar stripper” (So-St) network design to promote this SP-PCC over the solar-assisted (SA-PCC) counterparts. In this work, the absorber, the So-St network, and the solvent storage are synchronized within a generic design protocol. This design protocol primarily creates an extended design database, and then, applies a set of design filters to shortlist promising designs based on specific physical and/or performance criteria. As a buffering media, solvent storage capacity (SSC) is sized to ensure continuous solvent availability at both terminals (absorption–desorption) of the solvent cycle. Three key optimization strategies namely, the absorber stoppage time, synchronized solar multiple (SM), and multi-tank mix-match strategy are deployed to reduce the SSC and potentially improve the economic model. It is found that the latter strategy can save up to 49.5% of the SSC requirement compared to the basic two-discrete storage system. Furthermore, by combining these three optimisation strategies, it is found when SM increases by 2.5 folds, the SSC requirement is reduced to only 7.6% of the baseline SSC requirement when SM = 1. This calculation demonstrates the significant trade-off implications between the SM vs. SSC which can only be enhanced via economic optimizations. Validating this state-of-the-art technology by a rigorous techno-economic and life cycle assessment (LCA) could truly innovate the PCC technology and significantly improve its popularity and sustainability.

Feasibility study of an integrated COGES-DF engine power plant in LNG propulsion for a cruise-ferry

The feasibility study of an integrated COmbined Gas Electric and Steam-reciprocating engine propulsion plant for a Liquified Natural Gas (LNG) fueled cruise-ferry is assessed in this paper. Specifically, the purpose of this work is to respond to GNV shipowners’ need to equip ships with a propulsion system highly efficient in a wide ship speed range. The issue was addressed through the repowering study of the GNV La Suprema ship. Several power plant configurations based on different dual-fuel (DF) engine and gas turbine combinations have been tested in a cogeneration efficiency maximization study performed over a wide ship speed range. Afterwards, the best power plant was identified. Analysis showed that COmbined Gas Electric and Steam (COGES) plants have a great potential for marine propulsion application due to their benefits in cogeneration efficiency, emissions and required volumes. Furthermore, integrating a COmbined Gas Electric and Steam plant with small size dual-fuel engines revealed high cogeneration efficiency over wide ship operating conditions. The propulsion plant comprising a COmbined Gas Electric and Steam plant based on GE25.1 gas turbine and small size dual-fuel engines was proved to guarantee high cogeneration efficiency (47–52%) over a wide ship speed range (16–26 knots). In particular, a 51% cogeneration efficiency is provided for the current operating condition of GNV La Suprema. Moreover, the energy efficiency design index (EEDI) for the different investigated plants has been also evaluated, to verify their compliance with IMO limits. The selected propulsion plant provides an EEDI margin of 1.42–2.89 gCO2/(t*nm) with respect to the 2025 requirements. Finally, economic analysis was performed for four different ship routes and capital/operational costs have been computed. Overall, the proposed COmbined Gas Electric and Steam-reciprocating engine power plant revealed to be economically feasible over all of the operating conditions accounted for.

High Pressure Water Electrolyser Development for Space Exploration Surface Missions

Onsite production of oxygen and hydrogen is an essential contribution to any manned mission to the Moon or to Mars. In both environments there are elements consisting of bound oxygen, such as water ice-bearing consolidated regolith on the moon and carbon dioxide on Mars. These resources can be used to generate oxygen gas through electrolysis, together with energy carriers, namely hydrogen and CO, as by-products. Solid Oxide Electrolysis (SOE) technology possesses the highest potential for this application, due to the high operation temperature ranging from, 650°C to 900°C. Therefore, it can split each or both H2O and CO2, into H2, CO and O2 without compromising the integrity of the electrodes by poisoning, while the process can be further integrated with other thermal processes, such as the reduction of mineral oxide to provide overall very high system efficiencies. The solid oxide cell (SOC) technology is also fully reversible (i.e., the cell works both as electrolyser and as fuel cell) and can be used for unitised reversible fuel cell systems (URFCS) for energy storage and generation. This paper describes the developments under a European Space Agency (ESA) activity for the development of a high-pressure steam electrolyser system for exploration surface missions. The base case scenario considered is a hydrogen and oxygen production unit for lunar missions, where water for the electrolyser is generated from ice-bearing consolidated regolith.The development of the electrolyte supported cells was based in an all-ceramic approach. Specifically, electrolyte (8YSZ, 3YSZ, 6Sc1CeSZ and 10Sc1CeSZ) supported cells were fabricated comprising substituted lanthanum chromite La0.75Sr0.25Cr0.9Fe0.1O3 (LSCrF), as fuel electrode, and (La0.80Sr0.20)0.95MnO3-x (LSM) or (La0.60Sr0.40)0.95Co0.20Fe0.80O3-x (LSCoF), as oxygen electrodes. The electrochemical characterization and performance assessment in button cells (with an electrode footprint of ~0.8 cm2) was conducted for (i) steam electrolysis and (ii) reversible cell operation (fuel cell and electrolysis modes). All cells exhibited stable performance within the whole range of potentials, thus revealing the fact that Solid Oxide technology is in principle reversible and versatile in functionalities. Regarding steam electrolysis, the effect of hydrogen co-fed was investigated. The lack of reducing agent (H2) in the fuel side results in a non-trivial evolution of the current-potential curve, as the Nernst potential is not fixed and the production of a substantial concentration of hydrogen is required for the IV curve to follow the typical linear relation. However, within the linear IV region the performance of the cells is similar in presence or in absence of hydrogen, exhibiting ~2 A/cm2 at 1.5 V.Following these key developments, a high-pressure short stack is designed and constructed, comprising five (5) cells with an active area of 42 cm2. The stack is enclosed in a hot box consisting of the mechanical and thermal environment for the stack. To operate at pressure up to 10 bars, the hot box is placed inside a stainless-steel chamber made of standard piping elements. The hot box is complemented with all necessary balance of plant (steam generator, water system, gas storage) to realise a complete a steam electrolysis system which will be validated in operation against a load profile representing energy storage in Lunar environment for 3 lunar days (~2,126 h). Figure 1

Analisis Pengaruh Turbine Washing Terhadap Efisiensi dan Daya Pembangkit Turbin Uap

The steam turbine is one of the main components in the Geothermal Power Plant which acts as the prime mover is used to convert heat energy in steam into rotation energy. At PLTP X, steam is used to drive the turbine is in saturation conditions. The principle of the steam turbine is dry steam plant cycle. From July to August, it was known that there have been several decreases in generating power at Unit 2 at PLTP X. The efforts that can be done to overcome this problem is by turbine washing. This study aims to compare the performance of steam turbines based on thermal efficiency, isentropic efficiency and steam turbine generator power before and after turbine washing from the calculation results based on CEI/IEC 953-1, CEI/IEC 60953-3 and ASME PTC 6-2004 standards using the actual steam system operating parameter data collection, interviews and analysis. So that it gets an average increase in isentropic efficiency of 0,0564 %, thermal efficiency of 0,0082 %, the actual power generation of steam turbine is 162,72 kW and the largest power generation reaches 54.500 kW after the turbine washing steam rate of 7,5963 kg/kWh and the turbine heat rate of 3.607,3453 kJ/kWh.

Effects of steam sterilization on reduction of fungal colony forming units, cannabinoids and terpene levels in medical cannabis inflorescences

Medical cannabis (MC) production is a rapidly expanding industry. Over the past ten years, many additional phytocannabinoids have been discovered and used for different purposes. MC was reported beneficial for the treatment of a variety of clinical conditions such as analgesia, multiple sclerosis, spinal cord injuries, Tourette's syndrome, epilepsy, glaucoma, Parkinson disease and more. Yet, there is still a major lack of research and knowledge related to MC plant diseases, both at the pre- and postharvest stages. Many of the fungi that infect MC, such as Aspergillus and Penicillium spp., are capable of producing mycotoxins that are carcinogenic, or otherwise harmful when consumed, and especially by those patients who suffer from a weakened immune system, causing invasive contamination in humans. Therefore, there are strict limits regarding the permitted levels of fungal colony forming units (CFU) in commercial MC inflorescences. Furthermore, the strict regulation on pesticide appliance application in MC cultivation exacerbates the problem. In order to meet the permitted CFU limit levels, there is a need for pesticide-free postharvest treatments relying on natural non-chemical methods. Thus, a decontamination approach is required that will not damage or significantly alter the chemical composition of the plant product. In this research, a new method for sterilization of MC inflorescences for reduction of fungal contaminantstes was assessed, without affecting the composition of plant secondary metabolites. Inflorescences were exposed to short pulses of steam (10, 15 and 20 s exposure) and CFU levels and plant chemical compositions, pre- and post-treatment, were evaluated. Steam treatments were very effective in reducing fungal colonization to below detection limits. The effect of these treatments on terpene profiles was minor, resulting mainly in the detection of certain terpenes that were not present in the untreated control. Steaming decreased cannabinoid concentrations as the treatment prolonged, although insignificantly. These results indicate that the steam sterilization method at the tested exposure periods was very effective in reducing CFU levels while preserving the initial molecular biochemical composition of the treated inflorescences.

Investigation and damping of electromechanical oscillations for grid integrated micro grid by a novel coordinated governor-fractional power system stabilizer

ABSTRACT Electro mechanical low frequency oscillation generated in a micro-grid (MG) when subjected to uncertain disturbances, and stochastic renewable penetration is more aggravated especially when connected to grid. This needs more investigation for the smooth operation of power system and employment of power electronics-based costly control may not be economic for a MG. Also in the current scenario of deregulated market, more stress is imposed on the optimal use of present resources like mechanical torque control provided by turbine governors. In this work, a synchronous generator(SG)-based grid connected MG with Solar Photo Voltaic (SPV) and wind integration has been investigated for low frequency oscillation pertaining to small signal stability enhancement. A new simple governor (Gov)-Power system stabilizer (PSS), which is GOV-PSS controller has been proposed here with proportional integral derivative (PID), lead-lag and fractional lead-lag PSS actions, which coordinates the governor and PSS for oscillation damping and can be easily implemented. The gains of proposed controller are tuned by a new hybrid differential evolution with improved gray wolf optimizer with a multi objective function. The SPV, wind generations, and reference voltages are randomly varied giving rise to critical oscillatory instability, and proposed optimal controller is implemented to damp these oscillations. The excitation gains are also tuned for all generators subject to each condition such that the tuning of PSS would not adversely influence terminal voltage control. Time and frequency response of the system have been analyzed with 9-bus and 33-bus MG structures employing three generators of 1.32 MVA, 0.91 MVA, and 0.67 MVA. Solar and wind penetrations are executed with the bus connected to 1.32 MVA for 9-bus system and with all generators for 33-bus system. The oscillations due to renewable penetrations are found to be enhanced with reduced synchronous generation contribution. It is observed that properly tuned governor and PSS coordinate each other to enhance stability in proposed controller much effectively in contrast to only governor and PSS actions considered individually. Also turbine governors need not be blocked to damp inter area oscillatory mode, rather their efficacy is much enhanced with proposed control action, and this can be implemented to any SG-based generation including gas, steam, and hydro power-based plants.