Investigation of sludge re-circulating clarifiers design and optimization through numerical simulation

2004 ◽  
Vol 48 (11-12) ◽  
pp. 293-298
Author(s):  
S. Davari ◽  
M.J. Lichayee
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Thermal Power ◽  
Water Hardness ◽  
Design Parameters ◽  
Design And Optimization ◽  
Service Water ◽  
Boiler Tubes ◽  
Software Program ◽  
Technical Specifications

In steam thermal power plants (TPP) with open re-circulating wet cooling towers, elimination of water hardness and suspended solids (SS) is performed in clarifiers. Most of these clarifiers are of high efficiency sludge re-circulating type (SRC) with capacity between 500-1,500 m3/hr. Improper design and/or mal-operation of clarifiers in TPPs results in working conditions below design capacity or production of soft water with improper quality (hardness and S.S.). This causes accumulation of deposits in heat exchangers, condenser tubes, cooling and service water pipes and boiler tubes as well as increasing the ionic load of water at the demineralizing system inlet. It also increases the amount of chemical consumptions and produces more liquid and solid waste. In this regard, a software program for optimal design and simulation of SRCs has been developed. Then design parameters of existing SRCs in four TPPs in Iran were used as inputs to developed software program and resulting technical specifications were compared with existing ones. In some cases improper design was the main cause of poor outlet water quality. In order to achieve proper efficiency, further investigations were made to obtain control parameters as well as design parameters for both mal-designed and/or mal-operated SRCs.

scholarly journals Effect of fly ash on the strength of cement paste at early age

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 10-18
Author(s):  
Dung Trong Nguyen ◽  
Lam Van Tang ◽  
Hung Xuan Ngo ◽  
Phi Van Dang ◽  
Cuong Anh Ho ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Cement Paste ◽  
Power Plants ◽  
Building Materials ◽  
High Efficiency ◽  
Thermal Power ◽  
Early Age ◽  
Technical Specifications ◽  
Mineral Additives

In Vietnam, thermal power plants produce millions of tons of fly ash per year and cause a lot of problems for the environment. The re-use of fly ash as mineral additives in the production of building materials such as cement, concrete etc is a comprehensive solution that brings high socio-economic efficiency. However, to achieve high efficiency, the technical specifications index of fly ash needs to be studied and evaluated in detail because the content of added fly ash is very important for producing and manufacturing processes. This paper aims to study the influence of Formosa fly ash on the mechanical properties at the early age of cement paste. The mechanical properties of the samples which contain alternatively 10÷30% of fly ash was measured at the early ages (1, 3, and 7 days) by experimental methods. In addition, the microstructure analysis and differential thermal analysis methods have been used to interpret the obtained results.

RESEARCH OF COMPLEX MODIFICATION OF HEAVY CONCRETE

2021 ◽  
Vol 96 (4) ◽  
pp. 107-112
Author(s):  
YU.S. FILIMONOVA ◽  
◽  
E.G. VELICHKO ◽  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Complex Chemical ◽  
Composition And Structure ◽  
Combined Use ◽  
Mineral Additive

Modification of the composition and structure of heavy concrete with the use of a complex chemical-mineral additive consisting of fly ash from thermal power plants, a superplasticizer, a high-valence hardening accelerator AC and a fine-dispersed clinker component is considered. Modified concrete is characterized by an increase in compressive strength at a brand age by 67%, a decrease in the water content of a concrete mixture by 13.6% and an improvement in its workability by 11-12 cm. With the combined use of a superplasticizer and a high-valence hardening accelerator AC a significant synergistic effect is observed in the format of enhancing their plasticizing effect. The high efficiency of the application of the mixed-dispersed clinker component has been established.

scholarly journals The energy future of Saudi Arabia

2020 ◽  
Vol 181 ◽  
pp. 03005 ◽  
Author(s):  
Alberto Boretti ◽  
Stefania Castelletto ◽  
Wael Al-Kouz ◽  
Jamal Nayfeh
Keyword(s):  
Saudi Arabia ◽  
Energy Storage ◽  
Power Plants ◽  
High Efficiency ◽  
Thermal Power ◽  
Carbon Capture And Storage ◽  
Combined Cycle ◽  
Solar Photovoltaic ◽  
Battery Storage ◽  
Novel Technologies

In a recent publication, North European experts argue that “Saudi Arabia can achieve a 100% renewable energy power system by 2040 with a power sector dominated by PV single-axis tracking and battery storage”. They also say “Battery storage contributed up to 30% of the total electricity demand in 2040 and the contribution increases to 48% by 2050”. Based on considerations specific to the geography, climate conditions, and resources of Saudi Arabia, it is explained as batteries and photovoltaic solar panels are not the best choice for the country's energy sector. To cover all the total primary energy supply of Saudi Arabia by solar photovoltaic, plus battery storage to compensate for the sun's energy intermittency, unpredictability, and seasonal variability, is impracticable and inconvenient, for both the economy and the environment. Better environment and economy may be achieved by further valorizing the fossil fuel resources, through the construction of other high-efficiency plants such as the combined cycle gas turbine plants of Qurayyah, development of novel technologies for the production of clean fuels and clean electricity, including oxyfuel combustion and carbon capture and storage. Construction of nuclear power plants may also be more beneficial to the economy and the environment than photovoltaic and batteries. Regarding solar energy, enclosed trough solar thermal power systems developed along the coast have much better perspectives than solar photovoltaic, as embedded thermal energy storage is a better approach than battery storage. Further, a centralized power plant works better than distributed rooftop photovoltaic installations covered by dust and sand, rusted or cracked. Finally, pumped hydro energy storage along the coast may also have better perspectives than battery storage.

Effect of creep lifetime on geometric optimization of boiler tubes for thermal power plants

2019 ◽  
Vol 36 (5) ◽  
pp. 379-387 ◽  
Author(s):  
Vinh Phu Nguyen ◽  
Sangmin Lee ◽  
Woosung Choi ◽  
Seung Tae Choi
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Geometric Optimization ◽  
Thermal Power Plants ◽  
Boiler Tubes

Analysis of machinery breakdowns in power plants fed by biomass and MSW

2014 ◽  
Vol 8 (3) ◽  
pp. 301-311
Author(s):  
Stefano De Antonellis ◽  
Mario De Antonellis
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Insurance Companies ◽  
Time Loss ◽  
Significant Information ◽  
Content Type ◽  
Technical Specifications ◽  
Energy Utilities ◽  
Solid Biomass

Purpose – The aim of the study is to identify main failure phenomena and to evaluate reparation costs, reparation time, loss of profit and their relationship with power plant and faulty components age. In this work, several machinery breakdowns occurred in thermal power plants fed by solid biomass, biodiesel, biogas and municipal solid waste, have been investigated. In the period between 2004 and 2012, 23 faults have been analyzed. Design/methodology/approach – Each fault has been classified considering: power plant technical specifications, type of damage, reparation cost, reparation time and loss of profit (when data are available). The whole data have been, therefore, compared to find out significant information. Findings – It has been pointed out that relevant property damages are mainly caused by old components failure. In addition, the loss of profit is generally much higher than the property damage (six times on average basis). Originality/value – The study provides useful information that can be of interest for personnel of energy utilities, banks and insurance companies in managing power plants risks and in planning the availability of energy services.

scholarly journals The issue of improving the efficiency of nitrogen oxide neutralization systems in diesel internal combustion engines

2021 ◽  
Vol 1 (2) ◽  
pp. 101-112
Author(s):  
A.V. Shabanov ◽  
◽  
D.V. Kondratiev ◽  
V.K. Vanin ◽  
A.Yu. Dunin ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Internal Combustion Engine ◽  
Power Plants ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Combustion Engine ◽  
Thermal Power ◽  
Internal Combustion ◽  
Urea Solution ◽  
Exhaust Gas

The most effective method of reducing nitrogen oxides in diesel exhaust gas is selective purifica-tion by the SCR-NH3 method. The method uses ammonia released during thermolysis and hydroly-sis of a urea solution when it is injected through a nozzle into a neutralizer. This method has a rela-tively low efficiency of cleaning the exhaust gas from nitrogen oxides. The main factor hindering the achievement of high efficiency of the NOx neutralization system is the insufficiently high tem-perature during the implementation of this process. The article analyzes various ways to increase the efficiency of the neutralization process and proposes a new method for neutralizing NOx by using urea injection into the cylinders of the inter-nal combustion engine at the expansion stroke in a diesel internal combustion engine. Efficiency can be achieved due to a higher exhaust gas temperature in the cylinder of the internal combustion engine and an increase in the time of the process of thermolysis and hydrolysis of urea. The kinetics of the decomposition of nitrogen oxides, the process of NH3 oxidation, and the cal-culation of temperature conditions in the cylinder of a diesel internal combustion engine at the ex-haust cycle are considered. The experience of neutralization of NOx contained in the flue gases of thermal power plants, where NOx purification takes place at high temperatures without the use of a catalyst, is analyzed. It is shown that the modernization of the SCR-NH3 process, due to the injection of urea at the exhaust stroke in a diesel internal combustion engine, will simplify the existing method of NOx neutralization and at the same time obtain additional advantages for a modern high-speed engine

Standardization of digital technologies of simulator systems as a method of ensuring reliability of conditions of service of power engineering facilities (part 1)

2019 ◽  
Vol 12 (3) ◽  
pp. 177-189 ◽  
Author(s):  
S. I. Magid ◽  
I. Sh. Zagredtinov ◽  
S. V. Mishcheryakov ◽  
Ye. N. Arkhipova ◽  
V. L. Samoylov
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Software Tools ◽  
Power Engineering ◽  
Specific Reference ◽  
Operating Personnel ◽  
Normative Documents ◽  
Applied Software ◽  
Technical Specifications ◽  
Method Of Evaluation

Matters are considered of standardization of digital simulator systems for ensuring reliability of service of various power engineering facilities. Definitions are given to such terms as reliability, functioning conditions anf safety.Industry-specific reference normative documents are presented regulating requirements to technical means for training power engineering personnel. Mandatory minimum requirements and criteria are presented to simulators of operating personnel of power generation enterprises according to the rates established. Existing regulatory technical documents and regulations on requirements to simulators of operating personnel are presented in an overview. Particular emphasis is put on creating technical specifications for certification of applied software tools of simulators of thermal power plants and networks, including compliance with requirements to identification characteristics of software tools, to functional characteristics, to data processing functions, as well as to compatibility and safety, and to user interface.Of considerable importance is the method of evaluation of the simulator, especially with consideration of today’s information technology requirements. The current state of most of developments in Russia’s simulator-building is considered in details, including: creating electronic lectures on description of technical characteristics of power engineering facilities and processes therein, generalized models of process devices, limited mode models, partial topology models (nodal models), shells for construction of process devices, integrated analysers of electric equipment, analytic software complexes and ACS.Based on detailed analysis of implementation of applied software tools in the field of simulator-building at power plants and network enterprises of Russia, substantiated conclusions are presented on the software products under consideration, which have positive references from customers and known for various reasons as “simulators”; these, though meeting the requirements stipulated by regulatory documents, do not feature to the full extent the properties necessary for full-fledged training, namely, full-scale applicability, compatibility with all modes and topological adequacy, which largely reduces the efficiency of their application in commercial operation.

scholarly journals Shaping High Efficiency, High Temperature Cavity Tubular Solar Central Receivers

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4803
Author(s):  
Ronny Gueguen ◽  
Benjamin Grange ◽  
Françoise Bataille ◽  
Samuel Mer ◽  
Gilles Flamant
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
High Efficiency ◽  
Particle Temperature ◽  
Thermal Power ◽  
Heat Transfer Fluid ◽  
Geometrical Parameters ◽  
Shape Effect ◽  
Cavity Shape ◽  
Parameter Ranges

High temperature solar receivers are developed in the context of the Gen3 solar thermal power plants, in order to power high efficiency heat-to-electricity cycles. Since particle technology collects and stores high temperature solar heat, CNRS (French National Center for Scientific Research) develops an original technology using fluidized particles as HTF (heat transfer fluid). The targeted particle temperature is around 750 °C, and the walls of the receiver tubes, reach high working temperatures, which impose the design of a cavity receiver to limit the radiative losses. Therefore, the objective of this work is to explore the cavity shape effect on the absorber performances. Geometrical parameters are defined to parametrize the design. The size and shape of the cavity, the aperture-to-absorber distance and its tilt angle. A thermal model of a 50 MW hemi-cylindrical tubular receiver, closed by refractory panels, is developed, which accounts for radiation and convection losses. Parameter ranges that reach a thermal efficiency of at least 85% are explored. This sensitivity analysis allows the definition of cavity shape and dimensions to reach the targeted efficiency. For an aperture-to-absorber distance of 9 m, the 85% efficiency is obtained for aperture areas equal or less than 20 m2 and 25 m2 for high, and low convection losses, respectively.

scholarly journals Whisper and Roar

2014 ◽  
Vol 136 (07) ◽  
pp. 38-43
Author(s):  
Lee S. Langston
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Thermal Power ◽  
Electrical Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Marine Applications ◽  
Almost All

This article focuses on the use of gas turbines for electrical power, mechanical drive, and marine applications. Marine gas turbines are used to generate electrical power for propulsion and shipboard use. Combined-cycle electric power plants, made possible by the gas turbine, continue to grow in size and unmatched thermal efficiency. These plants combine the use of the gas turbine Brayton cycle with that of the steam turbine Rankine cycle. As future combined cycle plants are introduced, we can expect higher efficiencies to be reached. Since almost all recent and new U.S. electrical power plants are powered by natural gas-burning, high-efficiency gas turbines, one has solid evidence of their contribution to the greenhouse gas reduction. If coal-fired thermal power plants, with a fuel-to-electricity efficiency of around 33%, are swapped out for combined-cycle power plants with efficiencies on the order of 60%, it will lead to a 70% reduction in carbon emissions per unit of electricity produced.

scholarly journals Process Development of Fly Ash-Based Geopolymer Mortars in View of the Mechanical Characteristics

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2935
Author(s):  
Hatice Öznur Öz ◽  
Neslihan Doğan-Sağlamtimur ◽  
Ahmet Bilgil ◽  
Aykut Tamer ◽  
Kadir Günaydin
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Process Development ◽  
Thermal Power ◽  
Weight Ratio ◽  
Curing Temperature ◽  
Design Parameters ◽  
Alkaline Solutions ◽  
Solid Ratio ◽  
Flexural Tests

This study aimed to determine the effects of design parameters, including the liquid/solid ratio (L/S), Na2SiO3/NaOH weight ratio, and curing temperature, on class F fly ash-based geopolymer composites. For this purpose, two disparate sources of fly ash were supplied from Çatalağzı (FA) and İsken Sugözü (FB) Thermal Power Plants in Turkey. Two different L/S ratios of 0.2 and 0.4 were used. The Na2SiO3/NaOH ratios in the alkaline solutions were 1, 1.5, 2, 2.5, and 3 by weight for each type of geopolymer mixture. Then, 40 different mixes were cured at two specific temperatures (70 °C and 100 °C) for 24 h and then preserved at room temperature until testing. Thereafter, the physical water absorption properties, apparent porosity, and bulk density were examined at 28 days on the hardened mortars. Additionally, compressive and flexural tests were applied to the geopolymers at 7, 28, and 90 days. It was found that the highest compressive strength was 60.1 MPa for the geopolymer manufactured with an L/S of 0.2 and Na2SiO3/NaOH ratio of 2. Moreover, the best thermal curing temperature for obtaining optimal strength characteristics was 100 °C for the FB.

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