Correction and Its Application for Flue Gas Measured Temperature of Boiler

2005 ◽  
Author(s):  
Yueliang Shen ◽  
Tiansong He
Keyword(s):  
Heat Transfer ◽  
Flue Gas ◽  
Correction Method ◽  
Temperature Correction ◽  
Measured Temperature ◽  
Gas Temperature ◽  
Heat Transfer Theory ◽  
Reheat Steam ◽  
Temperature Errors ◽  
Heat Transfer By Radiation

The thermocouples of K type with one layer casing for reducing heat transfer by radiation was used to measure the flue gas temperature of two boilers with 670t/h evaporation. In order to diminish the measurement error, this paper offers a theoretical calculation method to correct the measured temperature basing on the heat transfer theory, the extraction thermocouple with three layers ceramic casing was used to check the reliability of corrected temperature. The measured temperature by extraction thermocouple is access to the corrected temperature, which means that the correction method in this paper has feasibility. This paper obtained the flue gas temperature and its distribution of two boilers with 670t/h evaporation applying such correction method, and analyzed the reasons why the reheat steam temperature is lower than design temperature for one of boilers. Although the flue gas temperature correction method in this paper isn’t perfect, it is benefit for improving the accuracy of measured temperature, reducing the temperature errors, and it has directive and reference functions for test or research engineers.

The Energy-Saving Optimization of the Organic Heat Transfer Material Heater

2012 ◽  
Vol 455-456 ◽  
pp. 284-288
Author(s):  
Wei Li Gu ◽  
Jian Xiang Liu
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Flue Gas ◽  
Theoretical Basis ◽  
Operation Management ◽  
Exergy Loss ◽  
Irreversible Processes ◽  
Design Parameters ◽  
Gas Temperature

this paper studies the typical irreversible processes such as combustion and heat transfer with temperature difference based on the theory of thermodynamics, analyzes the influencing factors on exergy loss in irreversible processes, on the basis of this analysis, proposes the energy-saving optimization measures on design and operation management of the organic heat transfer material heater, and specially points out that in the design process, objective function can be constructed with the exergy loss as evaluation index to determine the outlet flue gas temperature of furnace and the flue gas temperature, and provides theoretical basis for the determination of design parameters.

Applying the X-Ratio Correction to Calculated Air Heater Efficiency: An Alternate Method

2010 ◽  
Author(s):  
David C. McLaughlin ◽  
Joseph R. Nasal
Keyword(s):  
Heat Capacity ◽  
Heat Exchanger ◽  
Correction Factor ◽  
Mass Flow ◽  
Flue Gas ◽  
Correction Method ◽  
Gas Temperature ◽  
Original Design ◽  
Air Heater ◽  
The Impact

ASME PTC 4.3 on testing Air Heaters provides guidance for the calculation of gas-side efficiency as a measure of air heater performance. This code also provides for calculation of air heater X-ratio (XR), which is the ratio of the heat capacity (mass flow times specific heat capacity) of the air flowing through the heater to that of the flue gas. The code acknowledges the impact of XR on air heater efficiency, and dictates that the gas temperature leaving the air heater (and hence, air heater efficiency) be corrected for deviation from design XR by the use of “appropriate design correction curves” [1]. Unfortunately, such curves are rare, and therefore this important correction is usually ignored in routine air heater test calculations by power plant testing personnel, resulting in an incorrect calculation of air heater efficiency. This is particularly true for balanced draft boilers burning coal that are aged and have a significant amount of air leakage into the boiler setting. On these boilers, the ratio of combustion flue gas mass flow to combustion air mass flow is changed significantly from the original design, and therefore applying an XR correction factor is essential to calculating and reporting accurate air heater efficiency. This paper presents a method to calculate and correct for a deviation from design X-ratio based on standard heat exchanger analysis techniques, namely the ε-NTU method, which utilizes the concept of heat exchanger effectiveness (ε). A solution that results in applying the ratio of the design to actual XR’s as the correction factor is developed. The paper also provides empirical data from testing on a coal-fired boiler to validate the alternate correction method.

Furnace Design for Improved Exhaust Gas Circulation and Heat Transfer Efficiency

2020 ◽  
Author(s):  
Ayoola T. Brimmo ◽  
Mohamed I. Hassan Ali
Keyword(s):  
Heat Transfer ◽  
Metal Surface ◽  
Flue Gas ◽  
Waste Heat ◽  
Operating Conditions ◽  
Aluminum Production ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Exhaust Gases ◽  
Gas Circulation

Abstract In the aluminum production industry, metal furnaces are operated by diffusion flame over the metal surface to maintain the aluminum metal at the set point temperature for alloying and casting. Heat is transferred from the flame and its exhaust gases to the metal surface via radiation and convection. The exhaust gases leaves through the furnace’s chimney carrying a significant amount of waste heat to the atmosphere. Furnace efficiency could be improved by enhancing the heat transfer inside the furnace. In this study, a validated full-scale 3-D CFD model of a natural gas fired aluminum furnace is developed to investigate the effect of flue gas ventilation configurations and burner operating conditions on the heat transfer inside the furnace. Onsite measurements are carried out for the fuel and airflow rates as well as flue gas temperature. Four flue ventilation configurations are considered with eight furnace’s operation modes. The flue-gas’s waste-heat varies from 49–58%, with the highest value occurring at the high-fire operating mode. This indicates a significant room for improvement in the furnace performance. Results suggest that a symmetrical positioning of the exhaust duct favors effective exhaust gas circulation within the furnace and hence, increases hot-gases’ heat-transfer effectiveness inside the furnace. These results provide some guidelines for optimal aluminum reverberatory furnace designs and operation.

Numerical Analysis on Heat Transfer and Oxidation Characteristics of High-Temperature Steam Pipes in Supercritical Units

2014 ◽  
Vol 908 ◽  
pp. 81-84
Author(s):  
Pan Pan Sun ◽  
Shu Zhong Wang ◽  
Yan Hui Li ◽  
Xue Dong Li
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Oxide Film ◽  
Flue Gas ◽  
Working Fluid ◽  
Gas Temperature ◽  
Steam Temperature ◽  
Average Temperature ◽  
High Temperature Steam ◽  
Steam Pipes

In this paper, for Super304H steel, the growth law of oxide films and the heat transfer characteristics between the pipe and the working fluid were investigated by using numerical software ANSYS, which simulated comprehensively the effects of pipe size, flow rates of steam, flue gas temperature, and steam temperature on the formation and thickness of the oxide film. A bigger pipe wall thickness, a smaller steam flow rate or a higher flue gas temperature will lead the faster growth of the oxide film thickness, the heat flux density through the wall being smaller and the wall temperature being higher. With increases in steam temperature and thickness of the oxide film, the heat flux through the wall decreases with a small amplitude, and the average temperature of tube walls increases slightly.

scholarly journals An Experimental Investigation of Water Vapor Condensation from Biofuel Flue Gas in a Model of Condenser, (2) Local Heat Transfer in a Calorimetric Tube with Water Injection

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1310
Author(s):  
Robertas Poškas ◽  
Arūnas Sirvydas ◽  
Vladislavas Kulkovas ◽  
Hussam Jouhara ◽  
Povilas Poškas ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flue Gas ◽  
Gas Flow ◽  
Water Injection ◽  
Middle Part ◽  
Total Heat ◽  
Gas Temperature ◽  
Total Heat Transfer ◽  
Condensing Heat Exchanger

In order for the operation of the condensing heat exchanger to be efficient, the flue gas temperature at the inlet to the heat exchanger should be reduced so that condensation can start from the very beginning of the exchanger. A possible way to reduce the flue gas temperature is the injection of water into the flue gas flow. Injected water additionally moistens the flue gas and increases its level of humidity. Therefore, more favorable conditions are created for condensation and heat transfer. The results presented in the second paper of the series on condensation heat transfer indicate that water injection into the flue gas flow drastically changes the distribution of temperatures along the heat exchanger and enhances local total heat transfer. The injected water causes an increase in the local total heat transfer by at least two times in comparison with the case when no water is injected. Different temperatures of injected water mainly have a major impact on the local total heat transfer until almost the middle of the model of the condensing heat exchanger. From the middle part until the end, the heat transfer is almost the same at different injected water temperatures.

Analysis of Exhausting Flue Gas Temperature Abnormal Accompanied with the Boiler Load Changing

2013 ◽  
Vol 805-806 ◽  
pp. 1836-1842
Author(s):  
Qing Feng Zhang ◽  
Zhen Xin Wu ◽  
Zhen Ning Zhao
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Flue Gas ◽  
Gas Flow ◽  
Thermal Power ◽  
Transfer Principle ◽  
Air Leakage ◽  
Gas Temperature ◽  
Boiler Load ◽  
Hot Air

Based on the heat-transfer principle of air pre-heater, the influence mode of the changes of the air flow, the flue gas flow, the air leakage in different locations, to the temperature of the hot air and the exhausting gas was researched. The problem of a pulverized coal fired boiler, No.2, of a Thermal Power Plant, which the deviation of exhausting flue gas temperature increased to an abnormal extend when the boiler load rise up quickly was analyzed, the fault position and fault reason were located exactly, and the fault was eradicated by equipment maintenance at last. The results of this study have a certain significance to solve similar problems.

scholarly journals Structural parameters study on stainless-steel flat-tube heat exchangers with corrugated fins

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2743-2756
Author(s):  
Guifeng Gao ◽  
Fei Wang ◽  
Yongzhang Cui
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Flue Gas ◽  
Heat Transfer Performance ◽  
Structural Parameters ◽  
Transfer Performance ◽  
Gas Temperature ◽  
Flat Tube ◽  
Gas Condensation ◽  
Fin Length

A stainless steel corrugated fins and flat-tube heat exchanger is designed, which has a plate-fin structure. To optimize the structural parameters of this exchanger, including corrugation angle, corrugation pitch and fin length, 3-D simulation model and test were proposed. The numerical results indicated that the corrugation angle significantly affects both on heat transfer performance and pressure drop. The fin with angle, A = 0~20?, have demonstrated the higher heat transfer efficiency, lesser gas condensation, lower pressure drop, higher outlet flue gas temperature in low T region, and no exceeding the distortion temperature in high T region. Corrugation pitch and fin length influence thermal and hydraulic characteristics, outlet flue gas temperature, and fin temperature. To improve heat transfer performance, and reduce the fin temperature in high T region and ease gas condensation in low T region, smaller corrugation pitch and shorter fin length were recommended in the low T region, whereas higher values were more reasonable in high T region. Noticeably, the heat transfer and flow characteristics were better in the high T region than the low T region. Therefore, higher priority should be given to the structural optimization in the high T region in order to in-crease the heat transfer enhancement

scholarly journals Fired Heater Simulation, Modelling and Optimization

2021 ◽  
Author(s):  
Taj Alasfia M brakat ◽  
Mahmoud Adam Hassan
Keyword(s):  
Heat Transfer ◽  
Flue Gas ◽  
Model Simulation ◽  
Simulation Modelling ◽  
Furnace Operation ◽  
Conductive Heat ◽  
Gas Temperature ◽  
Perfect Agreement ◽  
Model Calculations ◽  
Aspen Hysys

Abstract In this study a dynamic model Simulation was carried out using ASPEN HYSY for industrial refinery fired heater, PID controller was applied to control the flue gas exit temperature. the simulation shows perfect agreement with the datasheet of the furnace. It was found that Increasing the number of the tube rows in convection bank from 2 to 3 allows us to recover approximately 5% of the overall efficiency, hence the duty furnace has increased from 65.9MW to 68.1MW and the fuel flow in like manner has increased from 5597kg/h to 5807kg/h moreover Adding more rows has a reverse return as we start to notice increase on the flue gas temperature. Furthermore, sensitivity analysis was conducted with HYSYS to determine one of the most important parameters that affect the performance of the heater based on the data generated from the simulation. MATLAB code was generated for efficiency calculation and for parameter manipulation, the code was designed to be flexible as possible, user will just need to replace the nominal fuel and air characteristics. for gaining optimum furnace operation the heat transfer inside the furnace was studied, and the results were compared with previous research involving furnace analysis to validate models, the heat transfer coefficient is determined by analysis of conductive heat transfer through the boundary layer. well-stirred model was used for mathematical model calculations and for optimization of furnace operation, the models were validated with ASPEN Exchanger Design and Rating(EDR) alongside ASPEN HYSYS

scholarly journals ANALISIS PERPINDAHAN PANAS PADA EKONOMISER DI PLTU PULANG PISAU

JTAM ROTARY ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Syahrul Fajar Setiawan ◽  
Aqli Mursadin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flue Gas ◽  
High Heat ◽  
Study Data ◽  
Feed Water ◽  
Gas Temperature ◽  
Combustion Gas ◽  
High Heat Transfer

Ekonomiser adalah alat yang digunakan untuk memanaskan air umpan sebelum memasuki boiler dengan memanfaatkan panas dari gas pembakaran di boiler. Dengan meningkatnya suhu air pengisi boiler, juga diharapkan meningkatkan efisiensi boiler. Dalam penelitian ini, pengumpulan data dilakukan di ruang kontrol dan data yang diambil, yaitu Tc.i (suhu economizer air yang masuk), Tc.o (suhu air keluar dari economizer), Th.i (suhu gas buang sebelum memasuki economizer) dan Th.o (suhu gas asap keluar dari economizer). Koefisien perpindahan panas tertinggi 4260.492 Btu / h.ft2. ° F dan koefisien perpindahan panas terendah 4251.243 Btu / h.ft2. ° F. Efisiensi tertinggi 87,43% dan terendah 80,76%. Economizer is a tool used to heat feed water before entering boiler by utilizing heat from the combustion gas in the boiler. With the increasing temperature of boiler filler water, it is also expected to increase boiler efficiency. In this study, data collection was carried out in the control room and the data that was taken, Tc.i (the temperature of the incoming water economizer), Tc.o (the exit water temperature of the economizer), Th.i (flue gas temperature before entering economizer) and Th.o (flue gas temperature exit the economizer). High heat transfer coefficient 4260,492 Btu/h.ft2.°F and low heat transfer coefficient 4251,243 Btu/h.ft2.°F. Highest the efficiency 87,43 % and the lowest 80,76 %.

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