scholarly journals MEASUREMENT OF THERMAL EFFICIENCY OF HEATING BOILER WITH FURNACE WALL WATERFLOW

2019 ◽  
pp. 169-176
Author(s):  
A. S. Klimov ◽  
R. T. Emelyanov ◽  
A. F. Aleksandrov ◽  
V. A. Taranov
Keyword(s):  
Thermal Efficiency ◽  
Lower Boundary ◽  
Heating Surface ◽  
Large Error ◽  
Furnace Wall ◽  
Temperature Fields ◽  
Thermal Probe ◽  
Local Coefficients ◽  
Measurement Results ◽  
Boiler Design

This article deals with the improvement of thermal efficiency of heating boilers with furnace wall waterflow. During one cycle in a PK-38 boiler the average level of the heat flow decreases by 25–30 %. The incident heat flux is measured with a thermal probe which, however, gives a large error in the measurement results. Experiments show that the error depends on the penetration of the thermal probe into the outer surface of thermal zone as well as on cavities in sealing the thermal probe, and different thermophysical properties of the latter and metal material of the heating surface. The accuracy of the measured parameters is affected by the thermal probe sealing. It is found that the distortion of temperature fields is more significant at the lower boundary of the thermal probe junction at frequently used sealing. Studies show that the waterflow leads to the restoration of local coefficients of thermal efficiency to the previous values. The obtained results can be used in boiler design and allow improving the measurement methods for thermal efficiency of heating boilers with furnace wall waterflow.

scholarly journals Calculation of temperature and velocity fields in the furnace chambers of tube ovens

2019 ◽  
Vol 124 ◽  
pp. 01019 ◽  
Author(s):  
A. V. Sadykov ◽  
D. B. Vafin
Keyword(s):  
Three Dimensional ◽  
Heating Surface ◽  
Methane Combustion ◽  
Combustion Products ◽  
Heat Fluxes ◽  
Flue Gases ◽  
Temperature Fields ◽  
Combustion Model ◽  
Band Model ◽  
Temperature And Velocity Fields

This paper presents the results of calculations of velocity and temperature fields in the radiation chamber of an energy-intensive technological tubular oven during the combustion of methane in air using acoustic burners of floor flame. The calculation method is based on the joint numerical solution of difference analogs of three-dimensional equations of energy transfer by radiation, convection and turbulent thermal conductivity, the movement of flue gases and the methane combustion model in the air. The radiation selectivity of flue gases is taken into account using a six-band model. The paper contains a diagram showing the organization of a three-dimensional modelling of acoustic burners. It also represents the isotherms of combustion products, the lines of the velocity vectors in the radiation chamber, distributions of surface densities of heat fluxes to the heating surface.

Parallel Flow Boiler Designs to Minimise Erosion and Corrosion From Dust Loaded Flue Gases

2013 ◽  
Author(s):  
Juergen H. Peterseim ◽  
Udo Hellwig ◽  
Karin Endrullat
Keyword(s):  
Gas Flow ◽  
Heating Surface ◽  
Parallel Flow ◽  
Flue Gases ◽  
Plant Performance ◽  
Energy Market ◽  
Test Results ◽  
Boiler Design ◽  
First Time ◽  
Energy From Waste

Improving power plant performance, availability and operational costs is crucial to remain competitive in today’s competitive energy market. The boiler is a key component to achieve these objectives, particularly so when using challenging fuels, such as municipal solid waste or exhaust gases with high dust contents. This paper describes an innovative boiler design that has been used for the first time in an Energy from Waste plant in Bamberg, Germany. The new boiler design disregards the traditional heating surface arrangement and instead uses tube bundles arranged in parallel to the gas flow, which provides several advantages, such as reduced fouling. The paper describes the Bamberg project (boiler design and project highlights) and first operational results after 30,500h of operation. Additionally, the paper investigates further options to reduce fouling through the use of dimpled tubes, especially the ip tube® technology. The technology is presented as well as first test results of such tubes in the Energy from Waste plant Rosenheim, Germany. The paper concludes with further applications for the parallel flow boiler design, such as cement kilns, to outline future markets.

scholarly journals Research and Application of Double-Reheat Boiler in China

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2197
Author(s):  
Hu Liu ◽  
Pengfei Yu ◽  
Jingwen Xue ◽  
Lei Deng ◽  
Defu Che
Keyword(s):  
Temperature Regulation ◽  
Thermal Efficiency ◽  
Heating Surface ◽  
Steam Temperature ◽  
Research Focus ◽  
Power Station ◽  
The World ◽  
Regulation Method ◽  
Vital Effect ◽  
Generation Unit

The ultra-supercritical (USC) double-reheat technology is an immediate area of research focus in China, since the thermal efficiency of USC double-reheat unit is higher than the USC single-reheat unit. The parameters and capacity of USC double-reheat unit in China have made major breakthroughs, and the thermal efficiency of the units are as high as 47–48%, which is the highest in the world. USC double-reheat boiler is one of the most important devices for USC double-reheat unit, and the design concept and precision have a vital effect on the operation of boiler and power station. The most difficult and important factors in the design of double-reheat boiler are the layout of heating surface and the steam temperature regulation method. Therefore, this work summarizes the arrangement of heating surface and temperature regulation method of existing double-reheat boiler in China. It is hoped that the work will set a benchmark for the development of double-reheat boiler and the future 700 °C power generation unit in the world.

A Novel Boiler Design for High-Sodium Coal in Power Generation

2015 ◽  
Author(s):  
Song Wu ◽  
Wengang Bai ◽  
Chunli Tang ◽  
Xiaowen Tan ◽  
Chang’an Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Heating Surface ◽  
Thermal System ◽  
The Novel ◽  
Gas Temperature ◽  
High Sodium ◽  
Steel Consumption ◽  
Boiler Design ◽  
Ignition And Combustion

Considering the severe fouling of high temperature convection pass in the boilers using high-sodium coals, a novel boiler design with a furnace exit gas temperature (FEGT) below 800 °C was proposed. The design was evaluated in different kinds of boilers with various capacities by examining thermal system arrangement, heat transfer, ignition and combustion, and steel consumption. The results indicate that, more radiation heating surface should be used in the thermal system arrangement of the novel boiler besides the volume-enlarged furnace. A marked decrease in the converted coefficient of radiation heat transfer is found in a volume-enlarged furnace due to the reduction in the average temperature of the flame. Moreover, the volume-enlarged furnace can adversely affect ignition and combustion. The cyclone-fired boiler is considered to be the most appropriate application for the novel design, for its combustion and heat transfer in furnace are carried out in divided chambers. A comparison of steel consumption demonstrates the expense of the novel boiler is approximately increased by 10% relative to the conventional one. In addition, an improved application with flue gas recirculation is described in detail, owing to its advantages of controlling FEGT and maintaining the level of convection heat transfer capability of the boiler.

A numerical study of the thermal efficiency of a tubular heating surface with split spiral-tape finning

2010 ◽  
Vol 57 (7) ◽  
pp. 598-602
Author(s):  
E. B. Filippov ◽  
G. B. Cherepennikov ◽  
T. G. Leshchenko
Keyword(s):  
Thermal Efficiency ◽  
Numerical Study ◽  
Heating Surface

The Research of Biomass Boiler Heating Surface Corrosion

2014 ◽  
Vol 700 ◽  
pp. 690-693
Author(s):  
Qiang Gao ◽  
Bo Huang ◽  
Wei Lv ◽  
Rui Chun Liu ◽  
Xin Yu Wang
Keyword(s):  
High Temperature ◽  
Integrated Control ◽  
Heating Surface ◽  
High Temperature Corrosion ◽  
Fuel Quality ◽  
Cross Sectional ◽  
Biomass Boiler ◽  
Surface Corrosion ◽  
Chloride Effect ◽  
Boiler Design

Nowadays against corrosion problems during combustion of biomass boiler heating surface temperature exists for biomass boilers high temperature corrosion dirt sample for analysis of main components, combined with the characteristics of biomass fuels and related documents, studied the corrosion process of alkali metal High temperature corrosion of chloride effect on the heating surface, through a cross-sectional analysis of the morphology of corrosion products that can make a small amount of Cl continuous corrosion reaction, namely Cl plays a catalytic role since the final in order to prevent and delay the high temperature heating surface corrosion problems, the need for integrated control from the boiler design, fuel quality and run into the furnace to adjust and other aspects.

Natural Convection in a Porous Medium: Effects of Confinement, Variable Permeability, and Thermal Boundary Conditions

1976 ◽  
Vol 98 (1) ◽  
pp. 42-48 ◽  
Author(s):  
R. J. Ribando ◽  
K. E. Torrance
Keyword(s):  
Heat Flux ◽  
Porous Medium ◽  
Natural Convection ◽  
Lower Boundary ◽  
Horizontal Layer ◽  
Temperature Fields ◽  
Uniform Heat Flux ◽  
Thermal Boundary Conditions ◽  
Variable Permeability ◽  
Real Fluids

Two-dimensional numerical calculations are reported for natural convection of a fluid in a porous, horizontal layer heated from below. Effects of the following parameters are examined: rigid (impermeable) and constant-pressure (permeable) upper boundaries; isothermal and uniform heat flux at the lower boundary; and permeabilities which are constant, or which vary with depth to simulate compaction of a porous medium or property variations of real fluids within the medium. Steady-state results are presented for the heat flux distribution on the upper surface, as well as for flow and temperature fields in the interior.

scholarly journals Convection regimes induced by local boundary heating in a liquid–gas system

2019 ◽  
Vol 873 ◽  
pp. 441-458 ◽  
Author(s):  
Victoria B. Bekezhanova ◽  
A. S. Ovcharova
Keyword(s):  
Gas Flow ◽  
Stokes Equations ◽  
Local Heating ◽  
Fluid Motion ◽  
Lower Boundary ◽  
Conjugate Problem ◽  
Temperature Fields ◽  
Layer System ◽  
Local Boundary ◽  
The Impact

In the framework of the complete formulation of the conjugate problem, the liquid–gas flow structure arising upon local heating using thermal sources is investigated numerically. The two-layer system is confined by solid impermeable walls. The Navier–Stokes equations in the Boussinesq approximation in the ‘streamfunction–vorticity’ variables are used to describe the media motion. The dynamic conditions at the interface are formulated in terms of the tangential and normal velocities, while the temperature conditions at the external boundaries of the system take into account the presence of local heaters. The influence of the number of heaters and heating modes on the dynamics and character of the appearing convective regimes is analysed. The steady and commutated heating modes for one and two heaters arranged at the lower boundary are investigated. The heating initiates convective and thermocapillary mechanisms causing the fluid motion. Transient regimes with the successive formation of two-vortex, quadruple-vortex and two-vortex flows are observed before the stabilization of the system in the uniform heating mode. A stable thermocapillary deflection appears at the interface above the heater. The commutated mode of heating entails oscillations of the interface with a change in the deflection form and the formation of travelling vortices in the fluids. The impact of particular mechanisms on the flow patterns is analysed. The paper presents typical distributions of the velocity and temperature fields in the system and the position of the interface for the considered cases.

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