scholarly journals Air Distributor Designs for Fluidized Bed Combustors: A Review

2016 ◽  
Vol 6 (3) ◽  
pp. 1029-1034 ◽  
Author(s):  
A. Shukrie ◽  
S. Anuar ◽  
A. N. Oumer
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Air Flow ◽  
Fluidized Bed Combustion ◽  
Key Factors ◽  
Successful Operation ◽  
Factors Affecting ◽  
Plate Design ◽  
Flow Through ◽  
Critical Overview

Fluidized bed combustion (FBC) has been recognized as one of the suitable technologies for converting a wide variety of biomass fuels into energy. One of the key factors affecting the successful operation of fluidized bed combustion is its distributor plate design. Therefore, the main purpose of this article is to provide a critical overview of the published studies that are relevant to the characteristics of different fluidized bed air distributor designs. The review of available works display that the type of distributor design significantly affects the operation of the fluidized bed i.e., performance characteristics, fluidization quality, air flow dynamics, solid pattern and mixing caused by the direction of air flow through the distributors. Overall it is observed that high pressure drop across the distributor is one of the major draw backs of the current distributor designs. However, fluidization was stable in a fluidized bed operated at a low perforation ratio distributor due to the pressure drop across the distributor, adequate to provide uniform gas distribution. The swirling motion produced by the inclined injection of gas promotes lateral dispersion and significantly improves fluidization quality. Lastly, the research gaps are highlighted for future improvement consideration on the development of efficient distributor designs.

Pressure Drop of Unidirectional Air Flow Through Rock Beds

1981 ◽  
Vol 24 (4) ◽  
pp. 1010-1013 ◽  
Author(s):  
Pitam Chandra ◽  
Louis D. Albright ◽  
Gerald E. Wilson
Keyword(s):  
Pressure Drop ◽  
Air Flow ◽  
Flow Through

scholarly journals Combustion adjustment and operation optimiztion of a 240 t/h circulating fluidized bed boiler

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2689-2698
Author(s):  
Xuemin Liu ◽  
Songsong Zhang ◽  
Yongqiang Chang ◽  
Zhongwei Wang ◽  
Guoli Qi
Keyword(s):  
Fly Ash ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Flue Gas ◽  
Circulating Fluidized Bed ◽  
Air Flow ◽  
Nox Emission ◽  
Unburned Carbon ◽  
Boiler Efficiency ◽  
Co Concentration

The influence of main operating parameters on boiler performance was studied, such as bed pressure drop, primary air-flow and secondary air-flow. Combustion adjustment tests were carried out on a circulating fluidized bed boiler with rated capacity of 240 t/h. From the test results, it can be seen that the loss due to exit flue gas is the largest heat loss of the boiler, accounting for more than 70% of the total heat losses. For coal fired boilers, compared with the loss due to unburned solids, the loss due to unburned gases is quite small. The unburned carbon con-tent in bottom ash is far lower than the value in fly ash. The trend of CO concentration in the exit flue gas is similar to that of the unburned carbon content in fly ash. To achieve higher boiler efficiency, the bed pressure drop is suggested to be maintained in about 8.5-9.0 kPa and the oxygen content in exit flue gas around 4%. The NOx emission concentration usually presents a negative correlation with CO concentration in exit flue gas. Through combustion adjustment and operation optimization, the NOx emission can be decreased by about 30% without affecting the boiler efficiency.

Minimum Air Fluidization Velocity Study of Specific 2-D Bubbling Fluidized Bed Reactor

2014 ◽  
Vol 699 ◽  
pp. 660-665
Author(s):  
M. Fadhil ◽  
M.S. Aris ◽  
A.H. Abbas ◽  
A.B.A. Ibrahim ◽  
N. Aniza
Keyword(s):  
Fluidized Bed ◽  
Particle Density ◽  
Flow Behavior ◽  
Numerical Approach ◽  
Combustion Efficiency ◽  
Fluidized Bed Combustion ◽  
Fluidization Velocity ◽  
Bubbling Fluidized Bed ◽  
Flow Through ◽  
Bed Expansion

Research on the thermodynamic behavior of sand beds was carried out using a commercial computational dynamic package. The work involved simulating, with the use of the Ergun equation, the air flow through a two-dimensional bubbling bed reactor to predict the bed character whilst considering the major effective function (particle size, particle density, bed height and reactor width). The Minimum Fluidization Velocity (Umf) values were then calculated before the optimum value of Umfneeded to ensure a workable Bubbling Fluidize Bed Combustor (BFBC) system. The effects of using different Umfvalues on the flow behavior were also investigated using the numerical approach at different times. The results from these investigations indicate that the bubbling region in the fluidized bed combustion can be correlated to the sand bed expansion with minimum errors and assist in enhancing the combustion efficiency by supplying the required volume of oxygen into the system.

Heat Exchange Effectiveness and Pressure Drop for Air Flow Through Perforated Plates With and Without Crosswind

1994 ◽  
Vol 116 (2) ◽  
pp. 391-399 ◽  
Author(s):  
C. F. Kutscher
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Pressure Drop ◽  
Air Flow ◽  
Ambient Air ◽  
Perforated Plates ◽  
Wind Speeds ◽  
New Type ◽  
Flow Through ◽  
Heat Exchange Effectiveness

Low-porosity perforated plates are being used as absorbers for heating ambient air in a new type of unglazed solar collector. This paper investigates the convective heat transfer effectiveness for low-speed air flow through thin, isothermal perforated plates with and without a crosswind on the upstream face. The objective of this work is to provide information that will allow designers to optimize hole size and spacing. In order to obtain performance data, a wind tunnel and small lamp array were designed and built. Experimental data were taken for a range of plate porosities from 0.1 to 5 percent, hole Reynolds numbers from 100 to 2000, and wind speeds from 0 to 4 m/s. Correlations were developed for heat exchange effectiveness and also for pressure drop. Infrared thermography was used to visualize the heat transfer taking place at the surface.

Enhanced CFD Modelling and LDA Measurements for the Air-Flow in an Aero-Engine Front Bearing Chamber: Part II

2014 ◽  
Author(s):  
J. Aidarinis ◽  
A. Goulas
Keyword(s):  
Pressure Drop ◽  
Rotational Speed ◽  
Ball Bearing ◽  
Complex Geometry ◽  
Computational Study ◽  
Air Flow ◽  
Mathematical Form ◽  
Operational Parameters ◽  
Aero Engine ◽  
Flow Through

A detailed computational study of the air-flow through the outer gap of the front bearing of an aero-engine is presented. The reason to carry out this study was to understand the flow through the bearing as a function of the operational parameters of the engine, which was necessary for the modeling of the flow in the whole bearing chamber. The complex geometry and the size of the bearing gap relative to the overall dimensions of the bearing chamber and the need for very precise and detailed information of the effect on the flow within the chamber of the bearing operational parameters, prohibited the solution of the flow through the gap together with the rest of the bearing chamber. A 3-D modeling of the flow through the outer bearing gap, which included a section of the ball bearing, was performed. Functions relating the pressure drop of the air coming through the bearing gap and the tangential component of velocity of the air exiting the bearing region, to the mass of air through the gap of the ball bearing and the rotational speed of the shaft were developed. The effect of the lubrication oil within the bearing was modeled as an anisotropic porous medium with a predefined law. In order to acquire in a mathematical form the above relationships a series of computational runs were performed. These relationships, in the form of second order curves, were subsequently introduced to the model of the bearing chamber as described in [1]. The constants of the relationships were derived through comparisons of the calculations with the experimental data. From the analysis it was concluded that the pressure drop across the bearing increases with the square of the rotational speed of the shaft with the mass flow of air through the ball bearing as a parameter and vice versa. For this particular ball bearing there is a region where, for any combination of rotational speed of the shaft and pressure drop through the bearing, there is no flow of air through the bearing. In this paper the detailed modeling methodology, the computational flow field, the boundary conditions and finally the results are presented and discussed.

scholarly journals Research on factors contributing to the development of accommodation facilities in areas with environmental constraints

2020 ◽  
Vol 159 ◽  
pp. 01007
Author(s):  
Lyudmila Maksanova ◽  
Alyona Andreeva ◽  
Ivan Kaurov ◽  
Darima Budaeva
Keyword(s):  
Primary Data ◽  
Small Scale ◽  
Key Factors ◽  
Successful Operation ◽  
Wastewater Disposal ◽  
Factors Affecting ◽  
Sensitive Areas ◽  
Environmentally Sensitive Areas ◽  
Environmentally Sensitive

Recently studies of factors affecting the successful operation of small-scale accommodation facilities have expanded significantly. Mandatory classification of hotels and other accommodation facilities is one of the key factors to increase their competitiveness. However, there are few works studying the problems of classifying small-scale accommodation facilities in conditions of infrastructural restrictions in environmentally sensitive areas. Therefore, the factors affecting the functioning of small-scale accommodation facilities in territories with environmental restrictions are discussed in this study in the context of the mandatory classification of hotels and other accommodation facilities in the Russia. The research uses the case of Enkheluk village’s guest houses (Russian Federation, Republic of Buryatia). Primary data obtained during the interviews with local entrepreneurs in 2018 was used in the study. The main infrastructural restrictions influencing the entrepreneurs providing temporary tourists’ accommodation were revealed: in the field of water supply, wastewater disposal, passing an environmental assessment. These problems, having a dynamic and interconnected nature, constrain the passing of mandatory classification by small-scale accommodation facilities. Possible ways of solving these problems are formulated. The study’s results can serve as the basis for further studies of factors affecting entrepreneurial and investment activities in the field of accommodation in environmentally sensitive areas.

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