Hydrodynamics of a Circulating Fluidized Bed with a Bubbling Bed Section Separated by an Inner Rim Baffle.

1998 ◽  
Vol 31 (5) ◽  
pp. 714-721 ◽  
Author(s):  
Hongwei Lei ◽  
Kazushige Tsujii ◽  
Munechika Ito ◽  
Masayuki Horio
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Bubbling Bed

Design Theory of Circulating Fluidized Bed Boilers

2005 ◽  
Author(s):  
Guangxi Yue ◽  
Junfu Lu ◽  
Hai Zhang ◽  
Hairui Yang ◽  
Jiansheng Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Design Theory ◽  
Circulating Fluidized Bed ◽  
Material Balance ◽  
The State ◽  
Transfer Model ◽  
Volatile Content ◽  
Cfb Boiler ◽  
Bubbling Bed

Studies on circulating fluidized bed (CFB) boilers have being conducted at the Tsinghua University (TH) for about two decades and much of works are done to link the fundamentals with practical application. A full set of design theory was developed and some key elements of this theory are presented in this paper. First, a classification of state of the solid-gas two-phase flow in CFB boiler is given. TH’s studies validated that a CFB boiler can be generally described as the superposition of a fast bed in the upper part with a bubbling bed or turbulent bed in the bottom part. A concept model of material balance for the open system of CFB boiler was developed and later improved as a more comprehensive 1-D model taking ash formation, particle attrition and segregation in bed into account. Some results of the models are discussed. Then the concept of State Specification of a CFB boiler is defined and discussed. The State Specification is regarded as the first step to design a CFB and a base to classify different style of CFB boiler technologies for various CFB boiler manufacturers. The State Specification adopted by major CFB boiler makers is summarized and associated importance issues are addressed. The heat transfer model originally developed by Leckner and his coworkers is adopted and improved. It is further calibrated with experimental data obtained on the commercial CFB boiler measurements. The principle, improvements and application of the model are introduced. Some special tools developed for heat transfer field test are also given. Also, combustion behaviors of char and volatile content are studied, and the combustion difference between a CFB boiler and a bubbling bed is analyzed. The influence of volatile content and size distribution is discussed. The concept of vertical distribution of combustion and heat in CFB boiler furnace is introduced and discussed as well. In the last, the suggested design theory of CFB boiler is summarized.

Design and Commissioning of the Largest and the Smallest Fluidized Bed Incinerator Ever Built by Lurgi

2003 ◽  
Author(s):  
H. Huenchen ◽  
L. Pachmayer ◽  
O. Malerius
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Flue Gas ◽  
Circulating Fluidized Bed ◽  
Waste Material ◽  
Design Parameters ◽  
Cross Sectional ◽  
Gas Cleaning ◽  
Bubbling Bed ◽  
Cleaning System

Since communities and companies are deciding to dispose sludges of different origin in a safe and nonpolluting way, more and more sludge is burnt either in mono-combustion or co-combustion units. Lurgi Energie und Entsorgung GmbH, one of the most experienced fluidized bed designer, is commissioning two bubbling bed incinerators of totally different incinerator size in 2002. In France the smallest fluidized bed incinerator ever built by Lurgi with a cross-sectional bed area of 4 m2 is designed to burn 750 kg (d.m.)/h sewage sludge. In spite of the small size it consists of all equipment necessary for sewage sludge incineration, including a disc dryer, a thermal oil boiler for heat recovery and a complete state of the art flue gas cleaning system. Air pollutants are removed in a circulating fluidized bed adsorber (CFB) designed in accordance with the new Lurgi CIRCOCLEAN® process. In United Kingdom the largest bubbling bed incinerator ever built by Lurgi with a cross-sectional bed area of 32 m2 is going to start its operation in 2002. The plant burns a mixture of thickened and mechanically dewatered primary and secondary sludge and different plastic residues from waste paper recycling plants. In order to provide sufficient disposal capacity of the waste material generated at the Kemsley Paper Mill site some parts of the installation consist of parallel streams or units (e. g. waste material handling and storage). The overall design throughput rate of mixed waste material is 22.8 t(a.r.)/h, corresponding to a thermal load of 29.1 MW. Due to the specific properties of the paper sludge, the formed ash can be used as an adsorbent/reactive compound for the capture of acidic pollutants. The flue gas cleaning system consists of a zeolite dosing unit to remove dioxins/furanes upstream of a baghouse filter. The paper presents the main design parameters of both disposal facilities and peculiarities of the burnt materials in comparison to other sludges. Since the plants are still in the commissioning phase only problems that might occur during the operation of the plant and tendencies in the operation behavior are described.

Modeling of Solid Fuel Combustion in Furnaces with a Circulating Fluidized Bed

2008 ◽  
Vol 39 (1) ◽  
pp. 65-78
Author(s):  
Yu. S. Teplitskii ◽  
V. A. Borodulya ◽  
V. I. Kovenskii ◽  
E. P. Nogotov
Keyword(s):  
Fluidized Bed ◽  
Solid Fuel ◽  
Circulating Fluidized Bed ◽  
Fuel Combustion ◽  
Solid Fuel Combustion

scholarly journals The Analysis of Influence of the Gangue in the Coal as Fired on the Coal Conveying System and the Boiler Operation of the Circulating Fluidized Bed Unit

2019 ◽  
Vol 118 ◽  
pp. 02011
Author(s):  
Su Pan ◽  
Yu Pengfeng ◽  
Linbo Liu ◽  
Han Jing ◽  
Xiao Shen
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Storage Conditions ◽  
Coal Gangue ◽  
Quality Data ◽  
Stable Operation ◽  
Coal Quality ◽  
Boiler Operation ◽  
Conveying System

The coal as fired, with unidentified characteristics of the coal gangue, was burned on a 300MW circulating fluidized bed unit. The equipment of the coal conveying system was damaged and the boiler operation was unstable. In response to the problems, the coal quality data and storage conditions of the coal were examined and the site was spot-checked to evaluate the coal quality characteristics. At the same time, the typical representative parameters of the coal handling system and boiler operation were selected. According to the analysis of coal quality and coal storage, the coal quality fluctuates greatly and the uniformity of particle size distribution is poor. There is actually the coal gangue with hard texture and hard to grind in the coal pile. The coal gangue will have adverse effects on the fine screening machine, fine crusher and other equipment. After burned this type of coal, the fluidized quality of the boiler bed is degraded to make an impact on the safe and stable operation of the boiler. It is recommended that the coal should be screened and then burned into the furnace to ensure safe and stable operation of the boiler.

Sign in / Sign up

Export Citation Format

Share Document