Добірка наукової літератури з теми "GT-ST PLANT"

Combined cycle power plant (CCPP) is a closed-cycle power plant, where the heat from the gas turbine’s (GT) exhaust gas will be streamed to the heat recovery steam generator (HRSG) to be utilized by steam turbine (ST). CCPP Block 4 (Jawa-2) PT Indonesia Power Priok POMU has an installed capacity of 880 MW, consists of 2 GT units (301.5 MW each) and 1 ST unit (307.5 MW). The performance of a power plant depends on its load, as the efficiency of the turbine generator is low when operated at low loads. The data as of July 2019 showed that 2.2.1 (2 GT, 2 HRSG, 1 ST) configuration has been used in three conditions where the CC net load was around 30 - 45 %, which in fact could be compensated by the 1.1.1 (1 GT, 1 HRSG, 1 ST) configuration. This resulted in a decrease of the CC net efficiency up to 21.34 %. The optimization that can be done is to change the load configuration from 2.2.1 to 1.1.1 at 0 - 50 % of CC net load through simulations, by including the influence of the GT and HRSG start-up processes. The result of this optimization is that the CCPP performance increases due to higher performance of each turbine generator. Thus, the optimization results during July 2019 provided energy saving of 1,146.09 MMBTU or equivalent to cost saving of IDR 152,249,551.76.

<p class="042abstractstekst">Developing biostimulants from salt-tolerant plant growth-promoting (PGP) bacteria is an emerging strategy for sustainable agriculture in the context of increasing soil salinization. This study aimed to isolate endophytic bacteria (EB) capable of promoting rice seed germination and seedling growth at different NaCl concentrations. Nine salt-tolerant EB strains were isolated and two, ST.6 and ST.8, with the rice seed promoting effect 99.3 and 99.7 %, respectively, were selected and identified as <em>Pantoea dispersa</em> and <em>Burkholderia cenocepacia</em>, respectively. ST.6 showed a higher value of the activity of phosphatase (617 mg P ml^-1), production of indole-3-acetic acid (19.7 µg IAA ml^-1), the activity of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (13.5 <em>µmol mg</em>⁻¹ protein h⁻¹), and production of siderophore (76.3 %). Especially, rice seedlings inoculated with strain ST.6 showed a significant improvement in root length (58.95 %), shoot length (16.6 %), dry biomass (7.0 %), the content of chlorophyll (46.2 and 57.1 % for chlorophyll a and b, respectively), carotenoids (22.2%), and proline (19.0 %). A decrease in antioxidant enzyme activities was also observed in the rice seedlings inoculated with either ST.6 or ST.8 strain under salt stress. Furthermore, the salt stress condition enhanced the colonization of roots by both studied endophytic bacteria. More experiments should be done to develop endophytic bacteria ST.6 and ST.8 as efficient bio-inoculants.</p>

The present study deals with effects of the air temperature, and the type of medium on the growth and form morfological structures of six <i>Seimatosporium hypericinum</i> isolates tested. St Jonh's Wort extract agar, St Jonh's Wort plant agar and PDA, oatmeal agar has been recognized as most useful for growth and sporulation of <i>S.hypericinum</i>. Mineral agar, appeared the least useful for growth and form acervuli and conidia. <i>S.hypericinum </i>can develop in a wide range of temperature, but the optimum one for the growth and sporulation of the fungus vary between 20°C and 28°C.

The effects of various plant origin materials such as defatted Cephalaria syriaca flour (0.5%), rosehip (2.5%), vital gluten (2.5%), and malt flour (2%), and their combination on the quality of whole wheat bread were investigated. The plant origin materials used showed significant effects on the specific volume, acidity, colour, and textural properties of whole wheat bread. In general the acidity, specific volume, cohesiveness, and springiness values of whole wheat bread produced by treatments with plant origin materials were higher than those of the control bread. Treatment 13 (2% malt flour + 0.5% defatted Cephalaria syriaca flour + 2.5% vital gluten) resulted in the highest specific volume and the lowest 1^st day crumb firmness. The results showed that the quality of whole wheat bread could be improved by adding various plant origin materials.

<p><em>The use of plastic mulches affects the microclimate in the vicinity of the</em><em> </em><em>plant by modifying the radiation on the soil surface and reduce the loss of water. </em><em>Pea is more nutritious and 2^nd food source after cereals at Pakistan, but due to lake of proper management, yield is still not up to mark as compare to developed world</em><em>. To reduce this problem, a field experiment was conducted to investigate the effect of mulching material and sowing dates on the yield of Pea.</em><em> The study consisted of three different mulching materials (Polythene Black, Polythene Blue and Polythene Brown) with three different sowing dates (1^st, 15^th and 30^th</em><em> </em><em>October) arranged in a Randomized Complete Block Design</em><em> </em><em>with three replications. The results showed that different sowing dates and mulching materials had significant</em><em> </em><em>effect on the yield parameters of Pea. Regarding sowing dates, maximum</em><em> </em><em>days to pod formation (8.08 days), pods plant^?1 (21.25), Pod weight (18.84 g) and pod yield (4.39 tons ha^?1) were noted in pea sown on October 1^st. Whereas, minimum data of days to pod formation (3.08 days), pod plant^?1</em><em> </em><em>(15.34), pod weight (13.17 g) and pod yields (2.69tons ha^?1) were recorded in pea sown on October 30^th. In case of mulching types maximum number of pods plant^?1 (19.00), pod length (6.89 cm), seeds pod^?1 (7.78), pod weight (17.34 g) and pod yield (3.69 tons ha^?1) were observed in pea mulched with Polythene Black, while minimum</em><em> </em><em>pods plant^-1, pod length, seeds pod^-1, pod weight and pod yield were found in control. The study suggested that pea should be sown on October 1^st while mulched with Polythene Black to produce maximum yield and production in agro environment of district Peshawar.</em></p>

Soil under maize cropping is among the most endangered by erosion. The effect of conservation tillage management on values of splash erosion when using shallow strip tillage before sowing maize was evaluated in the Central Bohemian region (Czech Republic) during the period 2010–2012. The following types of tillage management using conventional technology and shallow tillage were evaluated: ploughed plots with mulch formed by weed biomass (PL_W), ploughed plots with mulch from perennial ryegrass plants (PL_PR), ploughed plots without mulch (PL) and shallow tillage (ST) where the mulch was formed by cereals straw. Furthermore, values of the splash erosion, plants and plant residues coverage ratio of soil by image analysis and the stability of soil aggregates were monitored during the whole experiment. The average value of splash erosion (MSR) was higher by 18.7% in the variant of PL_W, lower by 35.9% in PL_PR, and lower by 39.5% in ST, than in the control treatment PL (MSR value for PL = 100%) for the whole evaluated period (2010–2012). The average values of the soil surface plant coverage ratio in the plots with mulch ranged from 1.5 to 43.0% at the beginning of the vegetation period, and from 4.9 to 85.5% in the second half of the vegetation period. A positive correlation was observed between the average values of the stability of soil aggregates and the plant coverage ratio of the soil surface in 2010 and 2011.

This paper evaluates the influence of ontogeny and the position of bine and offshoot leaves on the rate of photosynthesis (P_n), transpiration (E) and stomatal conductance (g_s) in hop plants. In the ontogeny influencing P_n, E and g_s among hops. The highest P_n was measured in phase 81&ndash;89 BBCH and E and g_s in phase 61&ndash;69 BBCH. The P_n increased over the course of ontogeny from the 1^st to 3^rd level of the hop plants. From the 61 BBCH phase, the leaves of the first and second level achieved a photosynthetic maturity and P_n value no longer increased. The third-level leaves achieved photosynthetic maturity from the 81 BBCH phase. Higher E was measured in the upper parts of the hop plant. P_n and E were higher in the bine leaves in the third level of the hop plant over the entire course of the vegetation period. In the first and second level of the hop plant, higher values of P_n were measured in the offshoot leaves. Differences in g_s were not noteworthy among the leaf types. Results show that a significant factor affecting the differences in P_n and E in hops is the age of the leaves.

Background. Diamondback moth (<I>Plutella xylostella</I> L.) has now acquired the status of the most dangerous pest of plants from the Brassicaceae family in the world, including Russia. In order to identify genotypes resistant to the pest, cabbage accessions from the VIR global collection were assessed in the field according to plant infestation and damage by diamondback moth in the vicinity of St. Petersburg.Materials and methods. The infestation of plants by diamondback moth was assessed on model accessions when examining all plants in the plot by (1) the number of larvae and pupae, and (2) leaf damage, assessed using a standard scoring scale. The number of adults was monitored using sticky Delta traps of two designs: (1) cardboard traps equipped with commercial dispensers with synthetic sex pheromone, and (2) plastic LED traps designed at VIZR.Results. The results of field surveys attested to very high variation among cabbage accessions in the rates of infestation and damage to plants caused by diamondback moth. The data on the abundance of adults caught by pheromone traps correlated well with the estimates of larval and pupal density of the pest on plants. The capture rate of diamondback moths with LED traps varied greatly during the season. In June/early July, i.e., during the period of the so called “white” nights, LED traps caught diamondback moths much worse than pheromone ones, but during the second half of July and August their capture rate significantly exceeded that of pheromone traps. As a result, the relationship between numbers of diamondback moth larvae on plants and adults in LED traps turned out to be negative. Conclusion. The resulting materials indicate obvious prospects of studying the VIR global collection in order to identify sources of host plant resistance to diamondback moth. The abundance of this pest in northern regions of its spreading is recommended to be controlled with pheromone traps.

<p>This research does to known: 1) the effect of season, 2) the effect of cover crop kind and organic fertilizer, and 3) the interaction of two factors on growth and yield of velvet bean as cover crops. This research was conducted in Tancep, Ngawen, Gunungkidul at 170 m usl, litosol, 5-17 cm level of soil tillage, 9-10^o elevation level, was started at December 2002 and finished at August 2003.</p><p>This research design was factorial-RCBD, 1^st factor was planting season on 2 level, rainy and dry seasons, 2^nd factor was cover crop kind on 6 levels, rase and putih gunungkidul velvet bean, Cm and Cp as conventional cover crops, rase and putih gunungkidul with organic fertilizer velvet bean. Per planting hole with 1 plant for velvet bean and 10 plant for coventional cover crop.</p><p>The result of this research were: 1^st, velvet bean growth on rainy season very high than dry season, 2^nd vegetative growth rate on velvet bean higher than conventional cover crop, 3^rd without fertilizer, velvet bean have some growth and yield comparing by fertilizer velvet bean and 4^th some yield variable, dry season was indicated better than rainy season.</p>

A coelomycete with appendage-bearing conidia, <em>R. sessilis</em>, was isolated three times from stems of living healthy <em>Pinus sylvestris</em> seedlings of the 1^st year growing in a nursery in central Belarus. Macroscopic and microscopic morphology of the fungus in culture is described.

The worldwide power industry structure is changing to a market economy to ensure commercial availability. This captive industry is essential for national development power & electricity infrastructure, but more than 40% of the input energy is lost during the plant operation with different thermal utilities. These precious dumped or waste heats have tremendous potential for the generation of multiple effects of energy like heating-power & cooling and also help to enhance the efficiency of thermodynamic power cycles. The novel and advanced thermodynamic systems are important because solar based on refrigeration systems have been discussed in the proposed title of research for different categories of waste heat source recovery. Therefore, this study investigates both theoretical and software-based simulation into the distinguishing feature of the advanced concept of the Rankine model called Organic Rankine Cycle (ORCs), which has three useful output heating-power and cooling production. The present research work focuses on two significant thermodynamic analyses: the integration of advanced thermodynamic cycles and the heat recovery system with employment of solar thermal systems, and the second is complete thermodynamic analysis, consisting of Energy and Exergy analysis. The traditional approach of thermodynamics analysis is based on the 1st law and 2nd law of thermodynamics. The 1st law of thermodynamics (FLT) gives the work, heat transfer, energy performance, thermal efficiency. In contrast, the 2nd law of thermodynamics (SLT) provides the system's actual performance by entropy generation (exergy) principle. The quantity and quality of energy (useful energy) are estimated through the FLT and SLT. The main objective of 2E analysis (energy-exergy) is to examine the theoretical and actual performance of proposed thermal systems to identify energy loss in integrated parts of the thermal system for efficient performance. The conventional mathematical modeling is suitable for physical system simulation, complex mathematical model development, and quantitative analysis. The statistical modeling helps to error estimation, system optimization, and comparative study of fundamental & predicted complex analysis results. Several statistical analysis methods are available with new artificial intelligence applications like linear or multi-linear regression method, artificial neural network method, least square method, and Taguchi-Annova xi | P a g e method. All optimization techniques are suitable for the least parameter identification, error count with complex problem-solving. This Research work is referred to as the multi-linear regression method for parametric identification and actual- predicted result comparisons. This research work consisted of four thermodynamics models for combined cooling, heating, and power generation effect using waste heat of different power plants. 1. Stack Flow heat recovery of Combined GT-ST plant using the LiBr-H2O vapor absorption cooling system. 2. Steam Turbine Heat recovery using solar integrated double bed activated carbonmethanol and activated carbon-R134a Vapor adsorption refrigeration system for space cooling purpose. 3. Reheating Rankine power generation heat recovery of the condenser by using a solar integrated organic Rankine cycle for combined cooling, heating, and power generation effect. 4. Combined reheating and regeneration steam power cycle, analysis and process heat recovery through a vapor generator by using the Vapour jet refrigeration system. All the above four systems are suitable for the low, medium, and high-grade temperature sources of heat recovery and produce the combined effect of energy efficiently. A parametric study has been carried out to analyze some influenced parameters such as condenser temperature, turbines (GT&ST) output, ORC performance, cooling effect of VARS, and vapor adsorption refrigeration and ejector cooling system. The influencing effect of gas turbine inlet temperature, compression ratio with different combustion of natural gases provides the best performance of the GT system for operation of ST plant under the different operating conditions of the compressor, GT, and combustion chamber. This case concluded as the maximum exergy loss found in the combustion chamber of GT system and exhaust flow system of ST system in terms of 41% and 8%, respectively. The combined and exergetic efficiency of the plant is estimated to be 41% and 38.5% respectively. In the present statistical model, 4 levels and 3 factors (Pressure ratio, operating temperature and type of fuel gases) have been considered. Furthermore, overall efficiency, gas turbine efficiency, heat loss in GT plant, Exergy destruction in thermal xii | P a g e utilities like Compressor, combustion chamber and gas turbine are investigated. The statistical modeling concluded that the comparative results of actual and predicted results at different compression ratio of combustible gases which affects the overall performance of combined GT-ST plant. This study helps to justify possible efficiency improvement by identifying the irreversibility of plant utilities. The combined reheating-regeneration power generation analysis concluded that the energy- exergy analysis for the Boiler, turbines, Feed heaters, condenser and pump majorly. The result of the thermodynamic analysis is computed as 42% of plant thermal efficiency, 70 % of steam generation unit efficiency. Maximum heat absorbed by economizer of plant as 39% is achieved, and quality of steam was found around 89-90% with 40TPH of coal consumption. Boilers, HPT, IPT, Super heaters have found best performance in analysis and Reheating-Regenerative Rankine method improves 6-8% in thermal efficiency. It has been observed that energy efficiency (theoretical) is always more than energy efficiency (actual), which means it helps to understand the performance of thermal power plants and justify possible efficiency improvement with efficient power generation opportunities like waste heat recovery technology employment. The performance of cooling systems of proposed research work is carried out the source temperatures available for both beds of Vapor adsorption refrigeration systems (VAdRS) from condenser exhaust, ETC solar system. The adsorbent and adsorbate pair for double bed VAdRS has been recommended by activated carbon as adsorbent and methanol and R134a as the adsorbate. The significant findings of present work are the maximum irreversibility found in Boiler as 47% in thermal power plants and solar generators as 12% of adsorption machines, whereas overall cooling effect from adsorption systems increases by 15% in double bed combination. EES software is used for all analyses. The VAM machine for stack flow heat recovery is performed by 0.708 of COP, a suitable cooling for space and water chilling purposes.

<em>Abstract</em>.—The current Lake St. Clair Great Lakes Muskellunge <em>Esox masquinongy </em>fishery is entirely self-sustaining and dominated by a catch-and-release ethic. Catch rates of Lake St. Clair Muskellunge are among the highest documented for this species, and angler catches of trophy Muskellunge are considered relatively commonplace. The proximity of Lake St. Clair to many potential new Muskellunge anglers, interest among some anglers in restoring a long-prohibited winter spear fishery, and warming temperatures associated with climate change pose potential threats to the quality of this fishery. We developed an age-structured equilibrium yield model to project the likely effects of altered size and harvest limits, increased angling effort, establishment of a winter spearing season, or warming temperatures on open-water angling catch rates of three size-classes of Lake St. Clair Muskellunge (all fish ≥ age 1, legal-sized fish > 107 cm, and trophy-sized fish > 127 cm). Our modeling indicated that changes in regulations in the Lake St. Clair Muskellunge fishery were unlikely to result in substantial changes to catch rates of Muskellunge of any size-class. Similarly, the current high rate of voluntary release would largely buffer catch rates of all size-classes of Lake St. Clair Muskellunge from increases in fishing effort. Our simulation of a winter spearing fishery indicated that only high levels of spearing effort and harvest would reduce open-water catch rates to a degree that would likely be objectionable to anglers. In contrast, the predicted catch rates of legal-and trophy-sized fish were highly sensitive to modeled reductions in growth. As such, the major threat to this trophy Muskellunge fishery appears largely outside the traditional toolbox of fisheries managers, hastening the need for development of resilient management and monitoring plans for this valuable fishery.

<em>Abstract</em>.— Long-term research indicates a significant and ongoing decline within the upper St. Lawrence River Muskellunge <em>Esox masquinongy </em>population. Index surveys show a sharp reduction in catch of both spawning adults and age-0 Muskellunge, and catch rates by anglers have similarly declined while harvest remains low. Other changes associated with population decline include presence of fewer female adult Muskellunge and a change in adult Muskellunge size structure (increase in proportion of fish <1,016 mm) in addition to more large individuals greater than 1,372 mm. A significant adult die-off occurred from 2005 to 2008 (103 adults recovered in U.S. and Canadian waters) concomitant with an outbreak of viral hemorrhagic septicemia (VHS). These population changes were also temporally correlated with detection and proliferation of invasive Round Goby <em>Neogobius melanostomus</em>, a known VHS virus (VHSV) reservoir, egg predator, and competitor with native fishes. Comparisons of index netting before and after VHSV and Round Goby invasions suggest a direct link to the decline, but because these are correlations, we can only explore these effects. To examine the viability of Muskellunge nursery sites, we repeated survival studies conducted in the early 1990s with experimental releases of advanced fry at four locations during 2013–2015. Findings indicate contribution to age-0 populations, but catches poststocking (wild and stocked) were lower compared to the 1990s. We review information regarding potential stressors, including VHSV and Round Goby invasion, and conclude that their combined effects have created significant uncertainty and challenges to sustainable management of the Muskellunge population. In response, the St. Lawrence River Muskellunge management plan should be updated with a focus on restoration of the declining Muskellunge stock. Recommended actions target advancing conservation and restoration of critical habitat, restoring lost subpopulations, and reducing mortality associated with angling (e.g., from handling and harvest).

<em>Abstract</em>.—Catfish have provided sustenance for Missouri inhabitants since prehistoric times, and their abundance and large size capabilities contribute to a popular sport fishery. Catfish were first propagated in state fish hatcheries and stocked in public and private waters in 1911. The Missouri Department of Conservation (MDC) began intensive rearing of channel catfish <em>Ictalurus punctatus</em> in 1938. Since 1942, fingerling channel catfish have been used in MDC’s private impoundment stocking program. In the early 1960s, MDC initiated production of advanced fingerling channel catfish (>20.3 cm) for stocking in small public lakes. Catchable-size channel catfish (>30.5 cm) are provided for kids’fishing clinics and the urban fishing program where angler effort is as high as 30,000 h/ha. Blue catfish <em>I. furcatus</em> and flathead catfish <em>Pylodictis olivaris</em> were first reared for stocking in public impoundments in 1978 and 1983, respectively. Commercial markets currently exist for channel catfish, flathead catfish, and blue catfish harvested from the Mississippi and St. Francis rivers. Catfish have comprised 21% of the commercial fish harvest since commercial fishing reports became a requirement in 1945. Channel catfish aquaculture has been a viable commercial industry in Missouri since the 1950s. The first official state sportfishing regulation established for catfish was a seasonal restriction in 1928 followed by a 30.5-cm minimum length limit for channel catfish in 1933. Separate daily sport fish bag limits are in effect for flathead catfish, blue catfish, and channel catfish. Currently, catfish are the most preferred sport fish group in Missouri. Most (75%) catfish anglers prefer to fish for channel catfish, most are harvest-oriented, and more than 80% prefer to fish with rod and reel. Competitive fishing for catfish began in the early 1980s, with most tournaments held on the Missouri and Mississippi rivers and associated lower tributary streams. Major management achievements include banning commercial catfishing on the Missouri River and developing an effective sampling technique for monitoring channel catfish populations in small public lakes. Current fisheries management efforts are directed by a statewide plan and primarily focused on measuring exploitation, growth, movement, and fecundity of blue catfish and flathead catfish in the Missouri River, upper Mississippi River, and associated tributaries, and growth and exploitation of blue catfish and flathead catfish in two large reservoirs.

Abstract In this study, performance of a combined power and cogeneration plant is evaluated. The plant is basically the captive power plant (CPP) of Numaligarh Refinery Limited (NRL), located in Golaghat district of Assam, India. The plant consists of a gas turbine (GT) plant as topping and a steam turbine (ST) plant as bottoming cycle. In the CPP, there was also provision for extracting steam from the ST at two different points for process heating in the refinery. CPP operational data regarding pressure, temperature and mass flow rates were collected from the refinery. It was observed that although the performance related data (the GT and ST power outputs) were available but the air flow rate (AFR) of the GT plant was not known. Therefore, this study aimed first at estimating the unknown AFR using an inverse method for which a differential evolution (DE) based optimization algorithm was used. Next, it was attempted to estimate both the AFR and fuel flow rate (FFR) simultaneously assuming that suppose the FFR is also not known. The objective was to find out better combinations of FFR and AFR over the base case corresponding to the single parameter (only AFR) estimation. The performance of the CPP was evaluated with the estimated AFR corresponding to the base case and also with the one of best FFR/AFR combination out of 25 such combinations obtained from simultaneous estimation. For the base case, the overall energy and exergy efficiency of the CPP were found to be 15.39% and 15.37% respectively. However, if the process heating is also taken into consideration, then these efficiencies in cogeneration mode increase to 21.04% and 21.0%. But with the selected best FFR/AFR combination obtained from simultaneous estimation, the overall energy efficiencies of the combined and the cogeneration plant could be improved from 15.39% to 17.68% and from 21.04% to 24.16% respectively. This has also reduced the total plant irreversibility from 183.729 MW to 152.955 MW. It was found that the maximum exergy destruction occurs in the combustion chamber (58.62%) of the GT plant followed by the utility boiler (29.37%) and heat recovery steam generator (3.76%). The results confirmed lower efficiencies for the plant indicating opportunities for further performance improvement particularly in the GT plant. NRL must go for other performance diagnostic tests which might give some actionable recommendations for restoring the lost performance. In the conclusions, other possible causes of low performances are discussed and necessary recommendations have been provided.

At the start of this new century, environmental regulations and free-market economics are becoming the key drivers for the electricity generating industry. Advances in Gas Turbine (GT) technology, allied with integration and refinement of Heat Recovery Steam Generators (HRSG) and Steam Turbine (ST) plant, have made Combined Cycle installations the most efficient of the new power station types. This potential can also be realized, to equal effect, by adding GT’s and HRSG’s to existing conventional steam power plants in a so-called ‘repowering’ process. This paper presents the economical and environmental considerations of retrofitting the steam turbine within repowering schemes. Changing the thermal cycle parameters of the plant, for example by deletion of the feed heating steambleeds or by modified live and reheat steam conditions to suit the combined cycle process, can result in off-design operation of the existing steam turbine. Retrofitting the steam turbine to match the combined cycle unit can significantly increase the overall cycle efficiency compared to repowering without the ST upgrade. The paper illustrates that repowering, including ST retrofitting, when considered as a whole at the project planning stage, has the potential for greater gain by allowing proper plant optimization. Much of the repowering in the past has been carried out without due regard to the benefits of re-matching the steam turbine. Retrospective ST upgrade of such cases can still give benefit to the plant owner, especially when it is realized that most repowering to date has retained an unmodified steam turbine (that first went into operation some decades before). The old equipment will have suffered deterioration due to aging and the steam path will be to an archaic design of poor efficiency. Retrofitting older generation plant with modern leading-edge steam-path technology has the potential for realizing those substantial advances made over the last 20 to 30 years. Some examples, given in the paper, of successfully retrofitted steam turbines applied in repowered plants will show, by specific solution, the optimization of the economics and benefit to the environment of the converted plant as a whole.

Abstract In this paper, a combined power and cooling system is thermodynamically analyzed. The system consists of a natural gas-fired gas turbine (GT) plant integrated with a heat recovery steam generator (HRSG), two steam turbines (STs), one organic Rankine cycle (ORC) and two absorption cooling systems (ACSs). With certain given input parameters, the GT plant produces net power of 36.06 MW, the two STs contribute 17.07 MW while from the ORC, 7.18 MW of net power was obtained. From the steam-operated ACS-I, a net 10.36 MW of cooing could be produced. Again, from the GT exhaust operated ACS-II, it was possible to generate additional 3.37 MW of cooling. From exergy analysis, it was found that the total irreversibility was the highest in the GT cycle with a net contribution of 180.412 MW followed by 4.178 MW from the HRSG, 3.561 MW from the ORC, 1.743 MW from ACS-I, 1.186 MW from ST-I, 0.812 MW from ACS-II, 0.175 MW from ST-II. The exergy efficiencies of the GT cycle, ORC, ACS-I and ACS-II were found 22.00%, 65.48%, 18.95% and 14.4% respectively. Regarding the power and cooling output, it can be concluded that these results are specific to the selected operating parameters. Further investigation is required, where, other similar configurations may be considered to make a final comment on the suitability of the proposed configuration from energy output and economic point of view.

Due to techno-economic assets, the demand of combined cycles (CC) is currently growing. Nowadays, in a diversified electricity mix, these plants are often used on a load cycling duty or in the intermediate load range. The ability to start quickly and reliably may be a decisional criterion for the selection of the plant, in addition to the design performance, the cost and the pollutant emissions. Therefore, together with the simulation of CC transients, a proper monitoring system aimed at keeping high plant performance during the transients is required. With the help of advanced measurement and monitoring devices, artificial intelligence (AI) techniques as expert systems (ES) and neural networks (NN) can fulfill this duty. The goal of this paper is to show that a NN technique can be used reliably to obtain the response of a complex energetic system, such as CCs, during a slow transient and consequently as part of an on-line monitoring system. In this work, a CC power plant is simulated by dividing it into three blocks, which are representative of the three main elements of the CC: namely the gas turbine (GT), the heat recovery steam generator (HRSG) and the steam turbine (ST). To each of them a NN is associated. Once the training and testing of the NNs is carried out, the blocks are then arranged in a series cascade, the output of a block being the input of the subsequent one. With this solution, the NN-based system is able to produce the transient response of a CC plant when the input information are the GT inlet parameters. The transient data, not easy to obtain from measurements on existing plants, are provided by the CCDYN simulator (Dechamps, 1995). The performance obtained by the NN based system are observed to be in good agreement with those given by CCDYN, the latter being validated on the basis of measurements in an existing plant. The NN code, providing the departures of the measured data from the predicted ones, can be considered as a proper system for on-line monitoring and diagnosis.

During the worldwide combined cycle power plant (CCPP) power plant building boom high pressure steam cycle has been the design of choice for the most power plant developers. In combined cycle power plant; there are many key areas that can be focused on for improving the thermal efficiency of the cycle and their performances. One of these areas is the unfired heat recovery steam generator so-called once through steam generator (OTSG). The unfired utility scale OTSG is a critical component in the combined cycle power plant, since it is the connection between the gas turbine (GT) and the steam turbine (ST) power units. In this paper, an adequate model has been developed for performance simulation of the once through steam generator OTSG in CCPP application. This model is well applicable for single and two-level of the steam cycle operation pressure. The developed model was tested against an existing OTSG installed at Manx Electricity Authority, and the obtained results and conclusions from this effort are satisfactory with a neglected error and will be a magnificent starting point for future improvements.

In the year 2000 one of Europe’s most flexible power stations was commissioned by the authors’ company. The existing fossil fired power station was modified by a “Parallel Repowering”. With that concept three gas turbines (GT) in combination with three heat recovery steam generators (HRSG) were tied-in additionally to the fired boiler. This concept is compelling especially for large steam power plants and offers more flexibility than “Full Repowering” in matching GTs with the existing steam turbine (ST). The key to maintaining reliability of the repowered unit is the ST modernisation. Plant operability enhancements provide the flexibility of the fired boiler and ST for load following and peaking purposes. The authors’ company was responsible for the complete conversion of the fossil fired power station into a modern combined cycle unit. This comprises the tie-in of new steam pipes, bypass stations and the upgrade of the steam turbine auxiliaries as well as the implementation of a new automation system parallel to the existing one. The “Parallel Repowering” offers a maximum of operation variations: •Conventional (Rakine cycle) mode. •Open cycle mode (only GT). •Combined cycle mode. •Hybrid mode. The non-OEM steam turbine needed to be modified for the combined cycle operation with GTs. The condenser load had to be kept as low as possible because of the existing condenser design. Auxiliary systems like the gland steam system and the drain system had to be modified for all different operating modes. Special design features, like the IP rotor cooling system and the flange heating system, had to be extended to operate under all circumstances. One essential difference to the existing operational mode is the necessity of a steam bypass operation. Existing cold reheat (CRH) piping is of carbon steel, so the ST needs to be started with an isolated HP cylinder. The following modifications for the HP turbine were necessary: •For the isolated HP cylinder operation non-return valves (NRV) were built into the CRH line at the HP turbine exhaust. •The HP cylinder will be automatically isolated by closure of the HP valves and the non-return valves in the CRH line, and the simultaneous opening of the HP vent line. •As no instrumentation was available for a reliable monitoring of the isolated operation, a controlled reverse flow from the CRH to the HP vent line was established. •The HP cylinder evacuation is controlled by a dedicated control logic.

Much of the steam-turbine based, power generating units all over the word are more than 30 years old now. Within a few years they will face the possibility of retirement from service and replacement. Nonetheless some of them are firm candidates for repowering, a technology able to improve plant efficiency, output and reliability at low costs. This paper summarizes a study performed to establish the feasibility to repower a 2 × 33 MW steam turbine power plant and the procedure followed until selection of the steam cycle more suitable to the project. The preferred solution is compared with direct replacement of the units by a new combined cycle. Various repowering options were reviewed to find “beat recovery” type repowering as the best solution. That well-known technology consists of replacing the steam generator by a gas turbine coupled to an HRSG, supplying steam to the existing steam turbine. Three “GT+HRSG+ST” arrangements were considered. Available gas turbine-generators — both industrial and aero-derivative type —, were surveyed for three power output ranges. Five “typical” gas turbine-generator classes were then selected. Steam flow raised at the HRSG, gross and net power generation, and heat exchanging surface area of the HRSG, were calculated for a broad range of usually applied, steam turbine throttle conditions. Both single pressure and double pressure steam cycles were considered, as well as supplemental fire and convenience of utilizing the existing feed water heaters. Balance of plant constraints were also reviewed. Estimates were developed for total investment, O&M costs, fuel expenses, and revenues. Results are shown through various graphics and tables. The route leading to the preferred solution is explained and a sensitivity analysis added to validate the selection. The preferred solution, consisting in a Class 130 gas turbine in arrangement 1–1–2, a dual-pressure HRSG and a steam cycle without feed-water heaters, win allow delivering 200 MW to the grid, with a heat rate of 7423 kJ/kW-hr. Investment was valued at $MM77.0, with an IRR of 15.3%. Those figures compare well with the option of installing a new GTCC unit: with a better heat rate but an investment valued at $MM97.5, its IRR will only be 12.4%.

The fuel cell model developed to this research is based on a solid oxide fuel cell (SOFC) integrated with a heat recovery steam generator (HRSG), a gas turbine (GT) and a steam turbine (ST). Three possible technological approaches are compared to suggest the desirable combine cycle. First approach indicates the generation of the required steam in the coupled SOFC and gas turbine cycle. Then the exhaust gas from gas turbine involves driving the HRSG. And the last one involves of using exhaust gases in the HRSG which drives the steam turbine by producing steam for additional power works. To achieve the more efficient conversation of the thermal energy to power output, the component design mainly HRSG and steam turbine have to be made in a great concern. And HRSG is considered as a triple pressure for the taken model. This article is also delineated the analysis of coal fed instead of normal methane gas fed, for the reforming power generation based on thermodynamic processes including CO2 Capture. External reforming in SOFC-HRSG plants fueled by high quality coal enhances efficiency due to improved exhaust heat recovery and higher voltage produced by higher hydrogen partial pressure in the anode inlet. For improving the whole cycle efficiency, power output generation from both SOFC and conventional system (steam turbine and gas turbine) are described as combine system. This model is simulated by the ASPEN plus software which is able to provide thermodynamic and parametric analysis to evaluate the effects of various parameters like air flow rate, temperature, pressure and fuel flow rate on the system performance. Some MATLAB simulations are also added to provide strong opinion for this model through this paper.

Industrial facilities are applications where the majority of electricity and steam productions are devoted to internal consumption rather than being exported. Oil refineries, smelters, and chemical and desalinization plants are typical examples. In the case of aluminum smelters, the vast quantities of electricity required by the process cannot be supplied by utilities from the grid and therefore cogeneration is required. Since power and/or steam supply interruptions might have catastrophic effects on the facility processes, the paramount requirement for “dedicated power plants’ is availability and reliability rather than high performance. It is common to find older D and E gas turbines used as the prime mover. In recent years, however, advanced gas turbines (GTs) successfully demonstrated close to 60% efficiency in combined cycle applications. The G and H technology classes, using steam to perform GT cooling duty, accumulated thousands of operating hours. Many improvements from G and H were also implemented into FX Class (latest variants of the air-cooled F technology class). Firstly, the paper addresses the strategies for incorporation of advanced GTs in captive applications where the equipment must cope with rapid changes in power demand, such as load swings, load rejection, harmonic currents, etc. Further, it examines a variety of designs, where there is a high and low process steam demand for process. The discussion encompasses plant optimization aiming at a high level of redundancy: multi-shaft arrangements, common steam headers, and heavy supplementary firing. The selection of an optimum steam turbine (ST) is also discussed, including steam extraction locations and the ability to operate efficiently with steam extraction on and off. Issues dealing with steam purity requirements and water treatment sizing will also be addressed. Since the amount and quality of the condensate return vary substantially, maintaining the water chemistry is essential. In continuation, the article will describe the challenges for the control system design and in particular, the requirements to maintain tight process conditions during transients. Finally, the paper will present the experience of an engineering, procurement, and construction (EPC) contractor for several “captive applications” projects.

<p>The Cherry St North, Commissioners St, and Cherry St South bridges are a series of four signature steel tied arch bridges located in Toronto, Canada. The bridges are being constructed over the Keating Channel and a new extension of the Don River. The arch legs of the bridges are composed of non-prismatic open sections using curved plates. The centre domes at the tops of the arches are also composed of open steel plate sections with plates in double curvature. Steel plate hanger from the arches to the closed steel box tie girders serve to transfer the superstructure gravity loads to the arches. The in-plane and out-of-plane structural stability of the non-prismatic open section arch legs required detailed consideration during design. This paper discusses the various approaches used to analyse and design the arch legs, including the use of approximate methods.</p>