A Innovative Solution to the Problem of Mill Rejects in Thermal Power Plants

Author(s):  
Animesh Dutta ◽  
Prabir Basu ◽  
Amit Ghosh ◽  
Prasun Chakraborty

The present paper discusses an innovative means for solving the problem of accumulation of waste coal in some pulverized coal fired plants. A major waste in a pulverized coal fired power plant is the reject produced from pulverizing mills. When coal is ground in a bowl mill heavy mineral matters are separated, but they still contain a small amount of coal mixed. However, the heating value of the rejects is generally too low for combustion in conventional boilers. As a result they find limited commercial use and are dumped in the plant adding to the fugitive dust, leaching problem and most importantly devastating damage to the landscape. The amount of mill reject is significant in older operating plant. In India for example, it is about 0.5–1.0% of coal throughput into the boiler. In this paper, an exercise is undertaken to show how these rejects could be burnt to produce low pressure process steam, which could save the bleeding of main steam of the power plant and thereby augment power generation. A subcompact novel circulating fluidized bed boiler has been designed, built and commissioned for this purpose. The present paper discusses the finding of above exercise.

Author(s):  
Ning Wang ◽  
Zhengdong Wang ◽  
Yingqi Chen

An on-line life prediction system is developed for remote monitoring of material aging in a main steam piping system. The stress analysis of piping system is performed by using the finite element method. A sensor network is established in the monitoring system. The creep damage is evaluated from strain gages and a relationship is given based on a database between the damage and residual life. Web technologies are used for remote monitoring to predict the residual life for every part of the piping system. This system is useful for safety assessment procedures in thermal power plant, nuclear power plant and petrochemical industries.


Author(s):  
Ahmed H. Bayoumy ◽  
Anestis Papadopoulos

Pressure surges and fluid transients, such as steam and water hammer, are events that can occur unexpectedly in operating power plants causing significant damages. When these transients occur the power plant can be out of service for long time, until the root cause is found and the appropriate solution is implemented. In searching for root cause of transients, engineers must investigate in depth the fluid conditions in the pipe line and the mechanism that initiated the transients. The steam hammer normally occurs when one or more valves suddenly close or open. In a power plant, the steam hammer could be an inevitable phenomenon during turbine trip, since valves (e.g., main steam valves) must be closed very quickly to protect the turbine from further damage. When a valve suddenly stops at a very short time, the flow pressure builds up at the valve, starting to create pressure waves along the pipe runs which travel between elbows. Furthermore, these pressure waves may cause large dynamic response on the pipeline and large loads on the pipe restraints. The response and vibrations on the pipeline depend on the pressure waves amplitudes, frequencies, the natural frequencies and the dynamic characteristics of the pipeline itself. The piping flexibility or rigidity of the pipe line, determine how the pipes will respond to these waves and the magnitude of loads on the pipe supports. Consequently, the design of the piping system must consider the pipeline response to the steam hammer loads. In this paper, a design and analysis method is proposed to analyze the steam hammer in the critical hot lines due to the turbine trip using both PIPENET transient module and CAESAR II programs. The method offered in this paper aims to assist the design engineer in the power plant industry to perform dynamic analysis of the piping system considering the dynamic response of the system using the PIPENET and CAESAR II programs. Furthermore, the dynamic approach is validated with a static method by considering the appropriate dynamic load and transmissibility factors. A case study is analyzed for a typical hot reheat line in a power plant and the results of the transient analysis are validated using the theoretical static approach.


2013 ◽  
Vol 441 ◽  
pp. 1072-1076
Author(s):  
Xiao Bin Huang ◽  
Pei Chao Zhang ◽  
Long Fei Liang

Coal blending technology is commonly used in coal-fired thermal power plant in recent years to ease cost pressures. But thermal power plants still use empirical formula to determine the economic fineness of pulverized coal. This approach cannot change economic fineness of pulverized coal based on the proportion of blending coal timely and accurately, resulting in increasing carbon content of fly-ash and reduced combustion efficiency of boiler. In this paper, a new method for determining pulverized coal economic fineness is proposed. Dry ash-free basis volatile, coal uniformity index, ignition temperature, proportion of blending coal are considered as parameters. According to the relationship between these parameters, the best coal fineness can be obtained in real-time. Influences of coal blending technology are reduced greatly and the accuracy of the economic fineness is improved.


2012 ◽  
Vol 58 (4) ◽  
pp. 351-356
Author(s):  
Mincho B. Hadjiski ◽  
Lyubka A. Doukovska ◽  
Stefan L. Kojnov

Abstract Present paper considers nonlinear trend analysis for diagnostics and predictive maintenance. The subject is a device from Maritsa East 2 thermal power plant a mill fan. The choice of the given power plant is not occasional. This is the largest thermal power plant on the Balkan Peninsula. Mill fans are main part of the fuel preparation in the coal fired power plants. The possibility to predict eventual damages or wear out without switching off the device is significant for providing faultless and reliable work avoiding the losses caused by planned maintenance. This paper addresses the needs of the Maritsa East 2 Complex aiming to improve the ecological parameters of the electro energy production process.


Author(s):  
Ye. G. Polenok ◽  
S. A. Mun ◽  
L. A. Gordeeva ◽  
A. A. Glushkov ◽  
M. V. Kostyanko ◽  
...  

Introduction.Coal dust and coal fi ring products contain large amounts of carcinogenic chemicals (specifically benz[a]pyrene) that are different in influence on workers of coal mines and thermal power plants. Specific immune reactions to benz[a]pyrene therefore in these categories of workers can have specific features.Objective.To reveal features of antibodies specifi c to benz[a]pyrene formation in workers of coal mines and thermal power plants.Materials and methods.The study covered A and G class antibodies against benz[a]pyrene (IgA-Bp and IgG-Bp) in serum of 705 males: 213 donors of Kemerovo blood transfusion center (group 1, reference); 293 miners(group 2) and 199 thermal power plant workers (group 3). Benz[a]pyrene conjugate with bovine serum albumin as an adsorbed antigen was subjected to immune-enzyme assay.Results.IgA-Bp levels in the miners (Me = 2.7) did not differ from those in the reference group (Me = 2.9), but in the thermal power plant workers (Me = 3.7) were reliably higher than those in healthy men and in the miners (p<0.0001). Levels of IgG-Bp in the miners (Me = 5.0) appeared to be lower than those in the reference group (Me = 6.4; (p = 0.05). IgG-Bb level in the thermal power plantworkers (Me = 7.4) exceeded the parameters in the healthy donors and the miners (p<0.0001). Non-industrial factors (age and smoking) appeared tohave no influence on specific immune reactions against benz[a]pyrene in the miners and the thermal power plant workers.Conclusions.Specific immune reactions against benz[a]pyrene in the miners and the thermal power plant workers are characterized by peculiarities: the miners demonstrate lower levels of class A serum antibodies to benz[a]pyrene; the thermal power plant workers present increased serum levels of class G antibodies to benz[a]pyrene. These peculiarities result from only the occupational features, but do not depend on such factors as age, smoking and length of service at hazardous production. It is expedient to study specific immune reactions to benz[a]pyrene in workers of coal mines and thermal power plants, to evaluate individual oncologic risk and if malignancies occur.


2011 ◽  
Vol 383-390 ◽  
pp. 4130-4133
Author(s):  
Song Feng Tian ◽  
Wei Wang ◽  
Yun Feng Tian ◽  
Shuang Bai Liu

There are many kinds of energy loss indicators in power plant, and there are some relevance among the various indicators. So extraction of the key indicators plays an important role between in energy loss analysis of power plants and optimal management of thermal power plants. Based on the characteristics of these indicators, the idea of rough sets was applied to the energy loss analysis of thermal power plants, then we proposed a new algorithm -- use fuzzy C means algorithm (FCM) to discrete cluster the energy loss indicators of thermal power plant, and then analysis simplified the results with algorithm Johnson. Real experiments (Chaozhou 1,2 and Ningde 3,4 assembling units which of the same type in the SIS system under the THA working condition)’ results had proved high accuracy and valuable of the algorithm.


2019 ◽  
Vol 109 ◽  
pp. 00119
Author(s):  
Volodymyr Yemelianenko ◽  
Vitalii Pertsevyi ◽  
Oleksandr Zhevzhyk ◽  
Iryna Potapchuk ◽  
Oleksandr Lutai

Analysis of the perspectives of the coal fuel for thermal power plants is carried out. The necessity of the experimental study for temperature measurement in the boiler furnace. The results of the experimental study are presented: temperature change over time at the burner outlet for different constant pressure value of the backlighting gas, dependence of the temperature at the burner outlet from the backlighting gas pressure for constant concentration value of pulverized coal in coal-air mixture, dependence of the temperature at the burner outlet from the concentration of pulverized coal in coal-air mixture for constant value of the backlighting gas pressure, temperature measurements for constant backlighting gas pressure value, constant value of the concentration of pulverized coal in coal-air mixture when plasmatron is switched and operates for some time range. The results of the study could be applied to the solid fuel treatment for different thermal units.


Author(s):  
V. Dhivakhar ◽  
Maju Varghese ◽  
Keerthi M. S. ◽  
S. Kaviya

About 40% of the Global Electricity produced is fuelled by coal. Although Coal has various advantages like good High Heating Value, easy availability etc., it also has various disadvantages. Green House Gas Released from Coal Thermal Power Plants is the single major contributor to Global warming. Coal is also nonrenewable. Hence it is important to analyze the viability of potential alternatives and reduce the usage of coal. In this assessment, various potential replacements of coal have been analyzed based on their High heating value (HHV) and their Global Warming Potential. The Global warming Potential (GWP) of the assessed fuels have been calculated by the Respiratory Quotient (RQ) Factor method. Hence a direct comparison between Coal and other replacements based on their HHV and GWP has been performed.


Author(s):  
Kajori Parial ◽  
S. Mukherjee ◽  
A. R. Ghosh ◽  
D. Sengupta

Coal combustion in thermal power plants releases ash. Ash is reported to cause different adverse health hazards in humans and other organisms. Owing to the presence of radionuclides, it is also considered as a potential radiation hazard. In this study, based on the surface radiation measurements and relevant ancillary data, expected radiation risk zones were identified with regard to the human population residing near the Thermal Power Plant. With population density as the risk determining criteria, about 20% of the study area was at &lsquo;High&rsquo; risk and another 20% of the study area was at &lsquo;Low&rsquo; risk zone. The remaining 60% was under medium risk zone. Based on the findings remedial measures which may be adopted have been suggested.


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