Large-scale Units Research Articles

Artificial neural network modelling in biological removal of organic carbon and nitrogen for the treatment of slaughterhouse wastewater in a batch reactor

Wastewater containing high concentration of oxygen-demanding carbonaceous organics and nitrogenous materials (chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN)) as nutrients emanated from small- to large-scale slaughterhouse units cause depletion of dissolved oxygen in water bodies and attributes to the threat of eutrophication. Biological treatment of wastewater is a useful tool through ages for the treatment of wastewater owing to its cost-effectiveness, reliability along with its innocuous output features. This paper deals with the treatment of slaughter house wastewater by conducting a laboratory scale batch reactor with different input characterized samples, and the experimental results were explored for the formulation of feed-forward back-propagation artificial neural network (ANN) to predict the combined removal of COD and TKN. The ANN modelling was carried out using neural network tool box of MATLAB (version 7.0), with the Levenberg–Marquardt training algorithm. Various trials were examined for the training of the ANN model using the number of neurons in the hidden layer varying from 2 to 30. The mean square error function and regression analysis were also applied for performance analysis of the ANN model. All the input data were logged-in after carrying out detailed experiment in the laboratory with a view to examine the performance of the batch reactor for the treatment of slaughterhouse wastewater. The experimental results were used for testing and validating the ANN model.

Electrospun Na3V2(PO4)3/C nanofibers as stable cathode materials for sodium-ion batteries

Sodium-ion batteries are considered as prime alternatives to lithium-ion batteries for large-scale renewable energy storage units due to their low cost and the abundance of sodium bearing precursors in the earth's mineral deposits. In the current work, a 3D NASICON framework Na3V2(PO4)3/carbon cathode electrode with 20-30 nm Na3V2(PO4)3 nanoparticles uniformly encapsulated interconnecting one-dimensional carbon nanofibers was fabricated using a simple and scalable electrospinning method. The Na3V2(PO4)3/C cathode showed an initial charge capacity of 103 mA h g(-1) and a discharge capacity of 101 mA h g(-1) (calculated on the total mass of Na3V2(PO4)3 and carbon) at 0.1C rate, and retained stable discharge capacities of 77, 58, 39 and 20 mA h g(-1) at high current densities of 2C, 5C, 10C and 20C, respectively. Moreover, because of the efficient 1D sodium-ion transport pathway and the highly conductive network of Na3V2(PO4)3/C, the electrode exhibited high overall capacities even when cycled at high currents, extending its usability to high power applications.

Designing Large-scale CO2 Capture Units with Assessment of Solvent Degradation

Abstract Solvent degradation is one of the main operational drawbacks of post-combustion CO 2 capture with amine solvents. Although the different degradation mechanisms have been largely studied in recent years, it is still impossible to predict the solvent losses and the emissions of degradation products that may occur in a CO 2 capture plant depending on its size and on its operating conditions. In the present work, we experimentally study the degradation of MEA (monoethanolamine) under accelerated conditions implying high temperature, continuous gas feed and vigorous agitation. A special focus is set on the oxidative degradation of MEA, which is studied in the absence of CO 2 . Based on the experimental results, we propose a kinetic model to describe both MEA oxidative and thermal degradation pathways. The degradation kinetics is then included into a global model of the CO 2 capture process, enabling solvent losses and emissions of degradation products to be predicted as a function of the process operating conditions. The predicted MEA loss is in the same order of magnitude as reported in degradation measurements from pilot plants, although lower by a factor 3. This kind of model assessing solvent degradation could and should be used for the design of large-scale CO 2 capture plants in order to simultaneously consider the energy consumption of the process and its environmental impact related to the emissions of degradation products and amine solvent. Further developments shall consider the effect of SO x , NO x and dissolved metals on MEA degradation.

Tannery Clusters in India and waste management practices in tannery intensive states – inventory and status

Clusterisation is undoubtedly the most economical, organized and self-sustaining driving mechanism for cleaner leather production. The Indian Tannery sector has particularly shown shifting trend from scattered units to clusters in recent decade with complete homogeneity i.e. industries involved only in tannery and allied activities. The paper gives insight into tannery clusters in India, with comparison of cluster characteristics and waste management practices in tannery intensive states. Study identifies 113 Tannery Clusters in India, tannery intensive states being Tamil Nadu (15 Clusters), Uttar Pradesh (13 Clusters), West Bengal (7 Clusters) and Punjab (15 clusters). Other States with prominence of tannery activities are Haryana(9 clusters), Maharashtra (13 clusters), Bihar (12 clusters), Andhra Pradesh,(7 clusters), Rajasthan (11 clusters), with fewer units in Gujarat (2 clusters), Karnataka (1 cluster at Bangalore), Odisha (4 Clusters), Delhi (2 clusters), Himachal Pradesh (1 cluster), Uttarakhand (1 cluster)and Goa (scattered units). Micro scale units are not considered in this study as the study pertains to small and medium enterprises. Jalandhar (Punjab) cluster has highest number of Medium scale units and second highest number of large scale units (10) after Tamil Nadu (13), inspite of the huge difference in total number of units in the clusters (110 in Jalandhar as against 704 in Tamil Nadu). Unit wise Tamil Nadu (704) has the highest number of units involved in tannery activities, followed by, West Bengal. Calcutta Leather Complex (462), Uttar Pradesh, Jajmau (405), and Punjab, Jalandhar (110). Tannery is the only sector with highest number of dedicated CETPs showing a strong initiative for greener indentation. Study reveals that 42 % of the total number of tannery clusters in four tannery intensive states is connected to CETP. Tamil Nadu has 93.3 % of units connected to CETP, followed by Uttar Pradesh (30.8%), West Bengal (14.3%) and Punjab (13.3%).

Solution of the mixed integer large scale unit commitment problem by means of a continuous Stochastic linear programming model

Power Systems all around the World faced in the last decade a large increase of penetration of power generation produced by Renewable Energy Sources, a large part of which (in particular wind generation and solar generation) is affected by high levels of uncertainty. Being Renewable Energy Sources only partially controllable all this uncertainty is transferred into Power System operation. Thus, numerical simulation of Power Systems needs to be able to cope with this uncertainty, that is Stochastic Programming techniques have to be considered. Anyway, numerical simulation of Power Systems also involves a very large number of variables, some of which are of integer nature: a large scale mixed integer stochastic problem has thus to be solved, but the requirement in computational power and time could reveal to be far too large. Thus, heuristic procedures must be introduced. In this paper it is introduced the sMTSIM model, based on a Stochastic continuous relaxation of the mixed integer Unit Commitment problem and on an heuristic procedure capable of re-introducing the mixed integer constraints.

Modeling and Solution of the Large-Scale Security-Constrained Unit Commitment

Security-constrained unit commitment (SCUC), as one of key components in power system operation, is being widely applied in vertically integrated utilities and restructured power systems. The efficient solution framework is to implement iterations between a master problem (unit commitment) and subproblems (network security evaluations). In industrial applications, both Lagrangian relaxation and mixed-integer programming are commonly applied for the unit commitment problem, and both linear sensitivity factor and Benders cut methods are used to generate additional constraints in the phase of network security evaluations. This paper evaluates capabilities and performances of each algorithm through technical discussion and numerical testing. Special topics on the large-scale SCUC engine development are also discussed in this paper, such as input data screening, inactive constrains elimination, contingency management, infeasibility handling, parallel computing, and model simplification. This paper will benefit academic researchers, software developers, and system operators when they design, develop and assess effective models and algorithms for solving large-scale SCUC problems.

Parameter Estimation in Modeling of Photovoltaic Panels Based on Datasheet Values

The increasing demand for renewable energy sources in recent years has triggered technological advancements in photovoltaic (PV) panels. Widespread use of large-scale PV units has revealed the sensitivity in PV panel modeling needed to estimate the amount of energy produced in different environmental conditions. For the formation of a PV panel model, parameters should be obtained by numerically solving characteristic equations of a transcendental nature. This study preferred using the Newton Raphson (NR) method owing to the suitability of equation structure. It is crucial that numerical solution starts with proper initial values. This study proposes a new approach to identifying initial values in order to decrease calculation time and increase the speed of numerical convergence. The proposed method was used in parameter estimation for different panel models. And, it was observed that owing to this method, the system converged with less iteration and the problem of failing to solve the system because of inappropriate initial values were eliminated. Convergence was obtained and the solution needed less iteration in all models.

Model based scale-up study of the calcium looping process

A 1-D dynamic calcium looping model was applied to a large scale calcium looping concept capturing CO2 from a 250MWt power plant. Several new features were added to the existing model frame in order to successfully simulate the large scale unit. Models were needed for new material fractions, such as ash and CaSO4, sulfur capture and heat transfer in the solid return system. The plant was dimensioned based on the experience from large CFB units and the heat transfer design was evaluated based on initial simulations of the design case. The unit was then simulated in five load scenarios ranging from full load to zero load, no flue gas flow to the carbonator. The scale-up of the process is feasible from the model’s point of view keeping in mind the assumptions and simplifications made in the modeling. The results from the simulations confirmed that successful operation of a large scale calcium looping unit requires good heat transfer design including cooling of the hot solids coming the calciner. Also the recirculation of flue gas in both reactors is necessary to ensure the sufficient fluidization for different flue gas flows from the source combustor. Solid circulation control is also critical because it affects heavily the thermal balance of the system as well as the capture efficiency and the CO2 balance. Results show that utilizing the experience gained from the large CFB-units coupled with new innovations, the scale-up of this process could be feasible in the near future. The ability to operate flexibly in different modes could give this technology an advantage needed for wide industrial utilization of the process.

Electrospun Sb/C Fibers for a Stable and Fast Sodium-Ion Battery Anode

Sodium-ion batteries (SIBs) are considered a top alternative to lithium-ion batteries (LIBs) for large-scale renewable energy storage units due to their low cost and the abundance of sodium-bearing precursors in the earth's mineral deposits. However, the development of anode materials for SIBs to date has been mainly limited to carbonaceous materials with minimal research devoted to high capacity alloy-based materials. In this study, an antimony (Sb)/carbon (C) electrode with ~30 nm Sb nanoparticles (NPs) uniformly encapsulated in interconnecting one-dimensional (1D) 400 nm carbon fibers (denoted as SbNP@C) was fabricated using a simple and scalable electrospinning method. This binder-free, current collector-free SbNP@C electrode demonstrated high capacity and stable long-term cycling performance at various current densities. The SbNP@C electrode showed an initial total capacity of 422 mAh/gelectrode and retained 350 mAh/gelectrode after 300 deep charge-discharge cycles under 100 mA/gSb. Moreover, because of the efficient 1D sodium-ion transport pathway and the highly conductive network of SbNP@C, the electrode preserved high overall capacities even when cycled at high currents, extending its usability to high power applications.

Chemical-looping combustion of solid fuels – Status of development

Chemical-looping combustion (CLC) of solid fuels is a technology with the potential of reducing the costs and energy penalty dramatically for CO2 capture. The potential for low costs is based on the similarity to coal combustion in fluidized beds. However, this assumes reaching high performance with respect to fuel and gas conversion, or that inadequate performance can be readily mitigated by downstream options. There are uncertainties with respect to the performance that can be reached in large-scale units, as well as with the extra costs needed to compensate for inadequate performance. Performance will be dependent on both reactor design and oxygen carrier properties. The status of chemical-looping combustion of solid fuels is discussed with respect to performance and experiences from pilot operation.

Economic Analysis of Processing of Guava (Psydium guajava L.) in Uttar Pradesh State of India

A study was conducted to analyse the economics of guava processing with the objectives of estimating benefit cost ratio, capacity utilization, cost of processing, price spread, marketing efficiency and constraints faced by guava processors in processing of guava in Allahabad district of Uttar Pradesh (U.P.) India. The processing of fresh guava was undertaken only by 10 units (processing firms) in the study area, so all the 10 units were evaluated for the present study. The processing units included cottage scale (03), small scale (05) and large scale (02). The study revealed that returns per rupee invested in cottage scale units, was calculated as 2.74 in making jelly and 2.99 in jam; for small scale units, it was 2.28 in jelly, 2.43 in jam and 1.89 in toffee; and for large scale units, the returns per rupee invested were 2.52 in the manufacture of jelly, 2.82 in jam and 2.01in toffee. As far as capacity utilization is concerned, the large scale units utilized 92.16% of installed capacity followed by cottage scale units with 86.73% and small scale with 79.89% capacity utilization, respectively. The cost of processing per quintal of guava was found to be Rs.176.60 (cottage scale), Rs.195.58 (small scale) and Rs.222.90 (large scale). Major problems faced by processors were non-availability of skilled labours, lack of capital, setting of guava products and degree of competition, etc. It could be concluded from the study that guava processing was an economically viable entrepreneurial activity and provided ample opportunities for employment generation particularly for the local youth, and also earning much required foreign exchange. This could be possible provided the government functionaries and concerned agencies take steps towards strengthening infrastructural support for a better marketing mechanism to be in place, and introduce export promotion schemes to boost the processing industry, given its competitive advantage. Efforts need to be made to encourage local unemployed youth to opt for guava processing as their livelihood source, by providing training and financial support to them.

Timbre as a structuring force in music

Most of the music we enjoy uses the musical qualities of different instruments to create specific perceptual and emotional effects that composers sculpt over time. Timbre is the auditory attribute that distinguishes different instruments. Research on timbre perception has demonstrated that it is multifaceted and contributes in many ways to the perceptual organization of musical structures. The art of structuring music with timbre is orchestration. A survey of orchestration treatises reveals the dearth of underlying theory, in sharp contrast to other traditional areas such as harmony and counterpoint, which have long theoretical traditions. We seek to develop a theoretical ground for orchestration practice starting with the structuring role that timbre can play in music. Many aspects of musical structuring are achieved by auditory scene analysis, the perceptual processes that result in unified events, integrated streams of events, groups of events segmented into phrases and sections, and larger-scale units extended over time that we call orchestral gestures. The roles that timbre plays in the manifestation of these principles in orchestration practice will be considered as potential elements of a theory of orchestration. How such principles might be incorporated into computer-aided orchestration systems and computer-aided orchestral rendering systems will also be examined.

Vibrational Analysis of an Industrial Fe-Based Fischer-Tropsch Catalyst Employing Inelastic Neutron Scattering

Inelastic neutron scattering (INS) has been used to obtain the vibrational spectrum of a technical-grade iron-based Fischer–Tropsch catalyst that has been taken from an industrial large-scale unit operation. Whereas previous reports on iron Fischer–Tropsch catalysts highlight the presence of retained carbonaceous species, the INS spectra reveal the additional presence of partially hydrogenated aromatic molecules.

Stand structure and small mammals in intensively managed forests: Scale, time, and testing extremes

Stand thinning and fertilization have the potential to create a diversity of forest habitat conditions to meet the goals of biodiversity conservation while sustaining wood and biomass production. Three factors are crucial to a better scientific understanding of how wildlife habitats develop in managed forests: real-world scale of treatments using adaptive management, several decades of time to monitor responses, and the testing of extreme treatments. Communities of arboreal and forest-floor small mammals occupy young coniferous stands and may serve as indicators of change in forest structure and function, and hence biodiversity. We tested the hypotheses (H) that, when compared with unmanaged (unthinned and old-growth) stands, large-scale pre-commercial thinning (PCT) and PCT with repeated fertilization, up to 16–21years after the onset of treatments, would enhance (H1) stand structure, (H2) abundance of southern red-backed voles (Myodes gapperi) and species diversity of forest-floor small mammals, and (H3) abundance of northern flying squirrels (Glaucomys sabrinus), in young lodgepole pine (Pinus contorta) stands in the south-central interior of British Columbia, Canada.Mean diameters and heights of crop trees in thinned stands were less than those in old-growth stands, but the low-density stands did have greater mean diameters than those in unthinned stands. Mean crown volume of pine crop trees was significantly greater in the low- and medium-density stands than in the high-density, unthinned, or old-growth stands. Mean density of overstory (range of 1010–1590 stems/ha) and understory conifers were similar in the thinned and old-growth stands. Mean species and structural diversity of total conifers were significantly higher in the heavily thinned (⩽1000stems/ha) than other stands. For vascular plants, mean abundance of understory herbs and total structural diversity were higher in heavily thinned and fertilized stands. Thus, some aspects of stand structure supported H1 while others did not.Mean abundance of M. gapperi was higher in old-growth forest than the younger managed and unthinned stands, except in years of low numbers, and hence did not support H2 that these treatments over a longer time-frame would enhance abundance of this species. Fluctuations in numbers, drier forest ecosystems, and slow development of forest-floor habitat with decaying woody debris and fungi may contribute to flexible habitat occupancy for M. gapperi. The second part of H2, that mean species diversity of forest-floor small mammals would be enhanced in heavily thinned and fertilized stands tended to be supported, particularly in the period prior to canopy closure. H3, that abundance of G. sabrinus would be maintained at levels recorded in old-growth forests by PCT of young stands, was supported for medium- and high-density stands.A sustained flow of wood products and structural features with their habitats for wildlife and biodiversity should be achievable with a wide range of stand densities from PCT and variable regimes of nutrient additions in intensively managed forests. Essential key elements include large-scale (operational-size) treatment units and long-term monitoring of installations over decades, preferably at 5- to 10-year intervals.

Distributed Microwave Pyrolysis of Domestic Waste

The scarcity of economically-viable crude oil has prompted chemical corporations to look for alternative sources of carbon and hydrogen to produce chemicals, biologics and other products. Biomass and waste matter are considered one of the foremost raw materials to develop all of these industries. Canada produces a tremendous amount of waste: 25 million tons (an average of 0.8 ton per capita), of which only 25 % is diverted (Statistics Canada 2008). The remaining 17 million tons per year is either incinerated or landfilled. This volume of waste is seen as an interesting biomass deposit and constitutes an opportunity to source alternative fuels and chemicals. The development and operation of centralized large scale pyrolysis plants to process domestic waste face several problems, which originate mainly from the wide-ranging composition of the feedstock. Also, these installations require a minimum volume of waste to be operational and cost effective, which leads to the costly collection and transportation of waste over long distances. Finally, process scale-up is extremely complex as the operation of large-scale pyrolysis units is subject to serious operational issues. To address these problems, a distributed pyrolysis strategy is proposed, which involves the deployment of small scale reactors at the waste production site for on-site processing. This approach reduces significantly the cost of waste transportation and collection and offers alternative ways of valorizing the biogas, bio-oil, and char. This presentation will discuss the cost benefits of a distributed strategy, the implementation strategy as well as the pyrolysis of common elements found in a garbage bag.

Study of chemical reactions effect on the design and the performance of an industrial secondary reformer reactor in the fertilizers plants

This paper will discuss and analyze the effect of chemical reactions number on the design and performance of the industrial secondary reformer reactor. The secondary reformer reactor is a large-scale unit in the Ammonia production plants. The secondary reformer reactor operation is adjusted to achieve the required stoichiometric ratio of Nitrogen and Hydrogen necessary for ammonia production. The Carbon Dioxide Reforming reaction equation in the catalyst bed of secondary reformer reactor has been investigated for two models A and B. The comparative study between the two models is carried out relative to the same operation conditions. The two models have been checked successfully against data available in the industrial secondary reformer reactor in the State Company of Fertilizers South Region in the Basra/Iraq. The theoretical results of model A are closer to the industrial plant data than model B.

The limiting & facilitating factors for export through Textile, Chemical & Pharmaceutical SMEs: In Indian perspective

The SMEs are playing a strategic role in economic growth and development of the country through their contribution to the creation of wealth, employment and income generation. The Textile & Chemical Industries are the leading segment in the SME sector. For the Indian economy textiles & chemical segments plays a major role. These segment of SMEs are exposed to the competitive pressures either directly from the market place or indirectly passed on from their higher ups in the chain. However, with SMEs dynamism, flexibility and innovative drive they are increasingly focusing on improved production methods, penetrative marketing strategies and management capabilities to continue and build up their operations. The Textiles exports consists of Fabrics, Ready-made garments, Cotton textiles, Textiles made from man-made fiber, Wool and Woolen goods, Silk, Handicrafts etc. Out of which man-made textiles and silk are showing the highest growth rate. The Indian Chemical Industry comprises both small and large-scale units. The fiscal concessions granted to the small-scale sector in mid-eighties led to establishment of a large number of units in the Small Scale Industries (SSI) sector. Currently, the Indian Chemical industry is in the midst of a phase of major restructuring and consolidation. With the shift in emphasis on product innovation, brand building and environmental friendliness, this industry is increasingly moving towards greater customer orientation. Even though India enjoys an abundant supply of basic raw materials, it will have to build upon technical services and marketing capabilities to face global competition and increase its share of exports. With the initiation of planned economy from 1951 and Government of India's subsequent industrial policy earmarked a special role for small-scale industries and medium scale industries in the Indian economy. Currently Textile & Chemical SMEs are facing the challenge of increased competition on account of new open markets. In such a context the ability to export is becoming a critical factor in the development and long term survival of many SMEs.

Understanding the puzzling resilience of the land share ownership in Russia: the input of Ostrom’s approach

This paper determines how the rule-in-use on access to agricultural land affects both the size of Russian farms and the nature of land property via enforcement mechanisms. The concept of “institutional arrangements”, developed by Ostrom, is used to show that land use practices by farmers can be considered a compromise between legal land access regimes and economic and social interests of nested communities. This compromise leads to the preservation of both large-scale agricultural production units and “land-share ownership” in Orel.

Research and Develop on Static Frequency Converter of Pumped Storage Power Plant

A static frequency converter start-up control strategy for pumped-storage power unit is presented. And rotor position detecting without position sensor is realized according to voltage and magnetism equations of ideal synchronous motor mathematics model. The mechanism and implementation method of initial rotor position determination and rotor position estimation under low frequency without position sensor are expounded and validated by simulations. Based on the mentioned control strategy, first set of a static frequency converter start-up device in China for large-scale pumped-storage unit is developed, which is applied to start-up control test in the 90 MW generator/motor of Panjiakou Pumped-storage Power Plant. Test results show that rotor position detecting, pulse commutation, natural commutation, and unit synchronous procedure control of static start-up are all proved. The outcomes have been applied in running equipment, which proves the feasibility of mentioned method.

Study on safety operation for large hydroelectric generator unit

Hydroelectric generator unit is a complex mechanical system which is composed of hydraulic turbine and electric generator. Rotary system is supported by the bearing bracket and the reinforced concrete structures, and vibration problem can't be avoided in the process of operating. Many large-scale hydroelectric units have been damaged because of the vibration problem in recent years. As the increase of the hydraulic turbine unit capacity and water head, the safe operation of hydraulic turbine has become a focus research in many countries. The operating characteristics of the hydraulic turbine have obvious differences at different working conditions. Based on the combination of field measurement and theoretical calculation, this paper shows a deep research on the safe operation of a large-scale Francis turbine unit. Firstly, the measurements of vibration, swing, pressure fluctuation and noise were carried out at 4 different heads. And also the relationships between vibrations and pressure fluctuations at different heads and working conditions were analysed deeply. Then the scientific prediction of safe operation for the unit at high head were done based on the CFD numerical calculation. Finally, this paper shows the division of the operating zone for the hydroelectric unit. According to the experimental results (vibrations, swings, pressure fluctuations and noise) as well as the theoretical results, the operating zone of the unit has been divided into three sections: prohibited operating zone, transition operating zone and safe operating zone. After this research was applied in the hydropower station, the security and economic efficiency of unit increased greatly, and enormous economic benefits and social benefits have been obtained.