scholarly journals Integrated research of slaging intensityof the boilerunit heating surfaceswhen burning non-project fuels

Author(s):  
E. A. Boiko ◽  
I. V. Zagorodnii

THE PURPOSE. Comprehensive research of the slagging intensity is the heating surfaces of the BKZ-420-140 boiler unit with solid slag removal at the Abakan CHP when burning non-project fuels. The relevance of the work is due to the technical necessity and economic feasibility of conversion boiler units to combustion of non-design coals. METHODS. The problem has been analyzed by methodology for conducting complex tests, measurements and processing of experimental data, as well as the results of experimental and computational studies of a boiler unit when operating on coals of various qualities. RESULTS. Qualitative and quantitative parameters for assessing the properties of off-design coals and their behavior in real operating conditions of radiation, semi-radiation and convective conditions, taking into account their modes and design functions, have been obtained. CONCLUSION: A computational analysis of the operating modes of boiler units when burning non-design fuels showed that a promising technology for involving non-design coals in the fuel and energy balance of a thermal power plant is providing a scientifically based mixture of design and nondesign fuels.Analysis of the slagging and polluting properties of non-design coals makes it possible to predict changes in the characteristics of the thermal efficiency of heating surfaces and to develop many practical recommendations for optimizing the parameters of the cleaning equipment installed on the boiler.Also, mixtures of fuels were determined for which the wall temperatures of the metal of the outlet stack of the superheater increase, which significantly reduces the strength characteristics of the surface.The assessment and prediction of the reliability of the heating surface is carried out by calculating the temperature of the metal wall in the most heat-stressed place.

2020 ◽  
Vol 4 (157) ◽  
pp. 127-133
Author(s):  
Y. Ponomarenko ◽  
M. Katkov ◽  
R. Semenenko

A thermal energy is one of the most significant sources of environmental impact.This is a consequence of both the use of mostly non-renewable natural resources and environmental pollution from thermal power plants. The intensity of this impact depends on many factors, namely the purpose, power, type of fuel used and operating mode. Existing studies have established links between emissions and characteristics such as power and fuel type for stationary operating conditions. At the same time, changes in operating conditions have a significant impact on environmental and economic characteristics. This article is devoted to establishing the relationship between the operational characteristics of gas boilers and their environmental and economic efficiency. The analysis was based on the field data obtained from steam and water boilers that are in commercial operation and uses the natural gas. It was found that for steam and water boilers, there is a well-conditioned non-linear relationship between the technological parameters of boiler operation, in particular gas consumption, the percentage of boiler load, the amount and temperature of flue gases with indicators of pollutants entering the atmosphere. The most significant factor affecting the environmental and economic characteristics of boilers is the percentage of load of boilers. The nature of the dependency is determined by the type of boiler and the setting mode. These dependences with a high degree of conditionality have a parabolic character, which makes it possible to assume the existence of adjustment modes that minimize environmental and economic costs. For steam and water boilers, the dependence of environmental impact on the percentage of load is direct. But for steam boilers in the range of data that were studied, it has a monotonous character, that is, it does not have an extremum point. For water boilers, it is possible to find the optimal loading level that minimizes environmental costs, but to confirm this assumption, additional research is needed at low boiler loading levels. The proposed method can be used to determine the operating modes of boilers and their settings, taking into account environmental and economic criteria. Keywords: water gas boilers, steam gas boilers, operating modes, environmental and economic characteristics.


2014 ◽  
Vol 1 (2) ◽  
pp. 48 ◽  
Author(s):  
Giovanni Angrisani ◽  
Carlo Roselli ◽  
Maurizio Sasso ◽  
Peter Tzscheutschler

Microcogeneration can guarantee sensible primary energy savings and greenhouse gas emissions reductions in the residential sector. In this paper, the results of experimental tests carried out on a microcogenerator (5.5 kW electric power and 14.8 kW thermal power) based on a natural gas fuelled internal combustion engine, integrated with a condensing boiler, have been analyzed. Tests have been performed out at Institute for Energy Economy and Application Technology (IfE) of Technical University of Munich (Germany). The test facility allowed to simulate the thermal energy requirements of a real residential application, represented by a Multi Family House consisting of 10 apartments, and to evaluate the energy flows of the conversion devices in actual operating conditions. Four type days, characteristic of Mediterranean climatic conditions, have been used to define space heating and domestic hot water user’s requirements. Experimental tests have been performed to implement energy and environmental analysis, comparing the system consisting of cogenerator and integration boiler with a reference system. Results showed that the former can achieve a primary energy saving of about 6%, and CO2 equivalent emissions reduction of about 12%. Finally, the algorithm defined by the European Directive on the promotion of high efficiency cogeneration has been implemented; it demonstrated that the primary energy saving is well above the limit value prescribed by the Directive. Therefore the cogeneration plant can access support mechanisms that can help to achieve the economic feasibility of the system, besides energy and environmental benefits.


2019 ◽  
Vol 82 ◽  
pp. 01001
Author(s):  
Maciej Bujalski ◽  
Maciej Żyrkowski ◽  
Daniel Nabagło ◽  
Krzysztof Szczepanek

The article deals with the problem of optimizing the operation of soot blowers in a pulverized coal-fired boiler based on the instantaneous degree of cleanliness of heating surfaces, determined in real time. The elaborated methodology of calculations and the algorithm that determines the optimal configuration of the blowers operation has been implemented and tested on a boiler with a capacity of 380 t/h. The indicator defining the degree of cleanliness of a given heating surface is calculated using available measurements of process parameters based on the epsilon-NTU method. The calculations are carried out in the DCS system for each surface individually (air and water heaters, evaporator, superheaters). During the standard operation of the boiler, the adopted methodology was verified, having analysed the usefulness of the tool to assess the boiler cleanliness under operating condition.


2020 ◽  
Vol 299 ◽  
pp. 845-851
Author(s):  
Yury V. Shcheglov ◽  
Natalia V. Fedorova ◽  
Dmitry A. Shaforost

Ash and slag materials (ASM), formed during the combustion of coal in thermal power plants, have abrasive properties, which are manifested during the operation of boiler units, ash collection, ash and slag removal. These properties must be considered to ensure durable trouble-free operation of thermal power plants. On the other hand, these properties can be used when planning measures for ash and slag material disposal. The results of experimental-industrial tests of ash and slag materials abrasive properties are presented in this paper. It was shown that, when cleaning metal surfaces of various shapes from old paint coatings, the consumption of crushed coal slag per 1 m2 of the surface being treated is on average 4.8 times less than the consumption of sand, the time of surface treatment with slag is on average 2.45 times less than with the use of sand in similar conditions. The empirical formulas to evaluate the technical and economic efficiency of using ash and slag materials as an abrasive in industrial applications are given.


This article describes the proposed approaches to creating distributed models that can, with given accuracy under given restrictions, replace classical physical models for construction objects. The ability to implement the proposed approaches is a consequence of the cyber-physical integration of building systems. The principles of forming the data structure of designed objects and distributed models, which make it possible to uniquely identify the elements and increase the level of detail of such a model, are presented. The data structure diagram of distributed modeling includes, among other things, the level of formation and transmission of signals about physical processes inside cyber-physical building systems. An enlarged algorithm for creating the structure of the distributed model which describes the process of developing a data structure, formalizing requirements for the parameters of a design object and its operating modes (including normal operating conditions and extreme conditions, including natural disasters) and selecting objects for a complete group that provides distributed modeling is presented. The article formulates the main approaches to the implementation of an important practical application of the cyber-physical integration of building systems - the possibility of forming distributed physical models of designed construction objects and the directions of further research are outlined.


Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 226
Author(s):  
Milana Treshcheva ◽  
Irina Anikina ◽  
Vitaly Sergeev ◽  
Sergey Skulkin ◽  
Dmitry Treshchev

The percentage of heat pumps used in thermal power plants (TPPs) in the fuel and energy balance is extremely low in in most countries. One of the reasons for this is the lack of a systematic approach to selecting and justifying the circuit solutions and equipment capacity. This article aims to develop a new method of calculating the maximum capacity of heat pumps. The method proposed in the article has elements of marginal analysis. It takes into account the limitation of heat pump capacity by break-even operation at electric power market (compensation of fuel expenses, connected with electric power production). In this case, the heat pump’s maximum allowable capacity depends on the electric capacity of TPP, electricity consumption for own needs, specific consumption of conditional fuel for electricity production, a ratio of prices for energy resources, and a conversion factor of heat pump. For TPP based on combined cycle gas turbine (CCGT) CCGT-450 with prices at the Russian energy resources markets at the level of 2019, when operating with the maximum heat load, the allowable heat pump capacity will be about 50 MW, and when operating with the minimum heat load—about 200 MW.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 607
Author(s):  
Tommy R. Powell ◽  
James P. Szybist ◽  
Flavio Dal Forno Chuahy ◽  
Scott J. Curran ◽  
John Mengwasser ◽  
...  

Modern boosted spark-ignition (SI) engines and emerging advanced compression ignition (ACI) engines operate under conditions that deviate substantially from the conditions of conventional autoignition metrics, namely the research and motor octane numbers (RON and MON). The octane index (OI) is an emerging autoignition metric based on RON and MON which was developed to better describe fuel knock resistance over a broader range of engine conditions. Prior research at Oak Ridge National Laboratory (ORNL) identified that OI performs reasonably well under stoichiometric boosted conditions, but inconsistencies exist in the ability of OI to predict autoignition behavior under ACI strategies. Instead, the autoignition behavior under ACI operation was found to correlate more closely to fuel composition, suggesting fuel chemistry differences that are insensitive to the conditions of the RON and MON tests may become the dominant factor under these high efficiency operating conditions. This investigation builds on earlier work to study autoignition behavior over six pressure-temperature (PT) trajectories that correspond to a wide range of operating conditions, including boosted SI operation, partial fuel stratification (PFS), and spark-assisted compression ignition (SACI). A total of 12 different fuels were investigated, including the Co-Optima core fuels and five fuels that represent refinery-relevant blending streams. It was found that, for the ACI operating modes investigated here, the low temperature reactions dominate reactivity, similar to boosted SI operating conditions because their PT trajectories lay close to the RON trajectory. Additionally, the OI metric was found to adequately predict autoignition resistance over the PT domain, for the ACI conditions investigated here, and for fuels from different chemical families. This finding is in contrast with the prior study using a different type of ACI operation with different thermodynamic conditions, specifically a significantly higher temperature at the start of compression, illustrating that fuel response depends highly on the ACI strategy being used.


Author(s):  
A. G. Zhuravlev ◽  
M. V. Isakov

The high importance of optimizing the operation of quarry transport is confirmed by the leading share of its costs in the total cost of mining. The current direction of optimization is the development and implementation of digital technologies for processing complex data on the parameters of transport vehicles. The solution of the above issues should be based on the results of scientific research on the collection and processing of information. Developed a set of techniques to perform experimental measurements of working parameters of mining dump trucks as part of a special unit experiments, and long monitoring measurements. A set of equipment for performing experimental measurements, as well as its installation on a dump truck is presented. The data of experimental measurements and a methodical approach to their analysis are presented. In particular, it shows the identification of operating modes of the power plant and the construction of the load diagram, the identification of elements of the transport cycle, etc. The approach to substantiation of innovative designs of power plants adapted to the conditions of a particular quarry is shown on the example of calculated schedules of energy consumption and reserve of recovery of braking energy. The proposed hardware-methodical complex is a research model for the development of methods for automated data collection and processing in the formation of elements of digital mining production.


2001 ◽  
Author(s):  
K. Bruce ◽  
R. Richards ◽  
D. Bahr ◽  
C. Richards

Abstract Work toward the development of a thin-film piezoelectric membrane generator is presented. The membrane generator is the central component of a new MEMS power generation system, the P3 micro power system. The P3 micro power system is based on a two-dimensional, modular architecture, in which the individual generic modules or unit cells each have all the functions of an engine integrated. Each unit cell is an external combustion engine, in which thermal power is converted to mechanical power through the use of a novel thermodynamic cycle that approaches the ideal vapor Carnot cycle. Mechanical power is converted into electrical power through the use of a thin-film piezoelectric membrane generator. This paper introduces the concept of the thin-film piezoelectric membrane generator, and describes its design and fabrication. Results of a study to characterize the performance of the piezoelectric membrane generator under expected operating conditions are presented. Current prototypes of the membrane generator are shown to be capable of producing a peak power of 0.1 milliWatts at a voltage of 0.5 Volts.


2021 ◽  
Author(s):  
Huacheng Zhang ◽  
Tutomo Hisano ◽  
Shoji Mori ◽  
Hiroyuki Yoshida

Abstract Annular gas-liquid two-phase flows, such as the flows attached to the fuel rods of boiling water reactors (BWR), are a prevalent occurrence in industrial processes. At the gas-liquid interface of such flows, disturbance waves with diverse velocity and amplitude commonly arise. Since the thin liquid film between two successive disturbance waves leads to the dryout on the heating surface and limits the performance of the BWRs, complete knowledge of the disturbance waves is of great importance for the characterized properties of disturbance waves. The properties of disturbance waves have been studied by numerous researchers through extensive experimental and analytical approaches. However, most of the experimental data and analyses available in the literature are limited to the near atmospheric condition. In consideration of the properties of liquids and gases under atmospheric pressure which are distinct from those under BWR operating conditions (7 MPa, 285 °C), we employed the HFC134a gas and liquid ethanol whose properties at relatively low pressure and temperature (0.7 MPa, 40 °C) are similar to those of steam and water under BWR operating conditions as working fluids in a tubular test section having an inside diameter 5.0mm. Meanwhile, the liquid film thickness is measured by conductance probes. In this study, we report the liquid film thickness characteristics in a two-phase HFC134a gas-liquid ethanol flow. A simple model of the height of a disturbance wave was also proposed.


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