Three phase Eulerian-granular model applied on numerical simulation of non-conventional liquid fuels combustion in a bubbling fluidized bed

The paper presents a two-dimensional CFD model of liquid fuel combustion in bubbling fluidized bed. The numerical procedure is based on the two-fluid Euler-Euler approach, where the velocity field of the gas and particles are modeled in analogy to the kinetic gas theory. The model is taking into account also the third - liquid phase, as well as its interaction with the solid and gas phase. The proposed numerical model comprise energy equations for all three phases, as well as the transport equations of chemical components with source terms originated from the component conversion. In the frame of the proposed model, user sub-models were developed for heterogenic fluidized bed combustion of liquid fuels, with or without water. The results of the calculation were compared with experiments on a pilot-facility (power up to 100 kW), combusting, among other fuels, oil. The temperature profiles along the combustion chamber were compared for the two basic cases: combustion with or without water. On the basis of numerical experiments, influence of the fluid-dynamic characteristics of the fluidized bed on the combustion efficiency was analyzed, as well as the influence of the fuel characteristics (reactivity, water content) on the intensive combustion zone.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.699.660 ◽

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.

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Combustion Characteristics of Heavy Liquid Fuels in a Bubbling Fluidized Bed

Journal of Energy Resources Technology ◽

10.1115/1.1446475 ◽

2002 ◽

Vol 124 (1) ◽

pp. 40-46 ◽

Cited By ~ 4

Author(s):

E. J. Anthony ◽

D. Y. Lu ◽

J. Q. Zhang

Keyword(s):

Heavy Metals ◽

Fluidized Bed ◽

Flue Gas ◽

Liquid Fuel ◽

Pilot Scale ◽

Liquid Fuels ◽

Feeding System ◽

Fluidized Bed Combustion ◽

Fuel Flexibility ◽

Bubbling Fluidized Bed

Liquid fuels such as bitumen, tars, and pitches are byproducts of heavy oil upgrading processes, and are usually contaminated with high sulphur and sometimes heavy metals contents as well. Fluidized bed combustion (FBC) appears to be a promising technology for the combustion of such fuels due to its inherent fuel flexibility and low emissions characteristics. The combustion of three liquid fuels, i.e., no. 6 oil, bitumen and pitch was investigated in a pilot-scale bubbling FBC unit. An efficient liquid fuel feeding system was developed and a bubbling FBC was successfully used to combust all three liquid fuels. The proportion of fuel escaping in the form of unburnt hydrocarbons in the flue gas was less than 0.4 percent and combustion efficiencies higher than 98.5 percent were achieved. However, combustion of liquid fuels tended to occur in the freeboard and, therefore, good mixing of the fuels in the bed was critical in achieving satisfactory combustion performance.

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Gas-Mixing in Bubbling Fluidized Bed Combustors: Hydrodynamics and Macromixing Associated With Bubble Bursting at the Bed Surface

17th International Conference on Fluidized Bed Combustion ◽

10.1115/fbc2003-111 ◽

2003 ◽

Author(s):

R. Solimene ◽

A. Marzocchella ◽

P. Salatino ◽

R. Ragucci

Keyword(s):

Fluidized Bed ◽

Fluid Dynamic ◽

Volatile Matter ◽

Solid Fuels ◽

Flow Structures ◽

Specific Reference ◽

Gas Mixing ◽

Fluidized Bed Combustion ◽

Bubble Bursting ◽

Bubbling Fluidized Bed

Gas-mixing phenomena may play a significant role in fluidized bed combustion of solid fuels. Issues associated with gas mixing include: a) effectiveness of mass transfer between the bubble and the emulsion phases in the bed; b) degree of mixing between segregated gaseous streams in plume-like or bubbly flow in the bottom bed; c) extent of mixing between segregated gaseous pockets/streams in the splashing zone or in the upper freeboard. Among the others, issues b) and c) turn out to be relevant to fluidized bed combustion of high-volatile solid fuels (biomass, RDF, etc.). In this case, the rate of gas mixing often overcomes intrinsic kinetics as the rate-controlling step in volatile matter burn-out, especially under “stratified” combustion conditions. Despite several and significant contributions to the subject, understanding of gas-mixing in bubbling fluidized beds is still poor and calls for additional investigation. The present work aims at investigating gas-mixing in bubbling fluidized bed with specific reference to the above issue c). A laser assisted imaging technique has been used to characterize the hydrodynamic patterns associated with the bursting of either isolated bubbles or couples of closely time-delayed bubbles at the surface of a fluidized bed. Quantitative image analysis procedures were exploited in order to assess parameters defining the general fluid-dynamic behaviour and macromixing of the bubble-generated gas pockets with the mainstream gas. The formation of toroidal flow structures upon bubble bursting is highlighted in the case of isolated bubbles. The toroidal pockets entrain mainstream gas and grow accordingly while rising along the splash zone. Toroidal flow structures are observed also in the case of couples of closely time-delayed bubbles, but interference between leading and trailing pockets leads to more complex structures characterized by multiple incoherent eddies. The relevance of macromixing to volatile matter burning under conditions of stratified fluidized bed combustion is assessed and discussed.

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Bubbling fluidized bed combustion of Syncrude coke

10.4095/304362 ◽

1987 ◽

Cited By ~ 2

Author(s):

E J Anthony ◽

H A Becker ◽

R K Code ◽

R W McCleave ◽

J R Stephenson

Keyword(s):

Fluidized Bed ◽

Fluidized Bed Combustion ◽

Bubbling Fluidized Bed

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Fate of bromine and chlorine in bubbling fluidized bed combustion – Formation of alkali halide aerosols

Fuel ◽

10.1016/j.fuel.2014.03.026 ◽

2014 ◽

Vol 128 ◽

pp. 390-395 ◽

Cited By ~ 6

Author(s):

Hao Wu ◽

Tor Laurén ◽

Patrik Yrjas ◽

Pasi Vainikka ◽

Mikko Hupa

Keyword(s):

Fluidized Bed ◽

Alkali Halide ◽

Fluidized Bed Combustion ◽

Bubbling Fluidized Bed

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Retrofitting 25T/h Pulverized Coal-Fired Boiler Into 35T/h Circulating Fluidized Bed Boiler for Burning Mixture of Coal and Bagasse

18th International Conference on Fluidized Bed Combustion ◽

10.1115/fbc2005-78041 ◽

2005 ◽

Author(s):

Han-Ping Chen ◽

Xian-Hua Wang ◽

Shi-Hong Zhang ◽

De-Chang Liu ◽

Yu-Hua Lai ◽

...

Keyword(s):

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Combustion Efficiency ◽

Economic Benefits ◽

Pulverized Coal ◽

Industrial Wastes ◽

Pollutant Emission ◽

Fluidized Bed Combustion ◽

Circulating Fluidized Bed Boiler ◽

Combustion Technology

In China, there are a large number of pulverized coal-fired industrial boilers, whose steam capacities are usually relatively small. These boilers can burn only high-grade coal and have low combustion efficiency. Furthermore, the combustion emissions, such as SO2 and NOx, pollute the environment severely. Therefore it is very important and urgent to adopt economically efficient and environmentally friendly technologies to retrofit these boilers. At the same time, there are many industrial wastes, such as bagasse, wood waste, rubbish, petroleum coke and so on, need burning disposal in China. Fluidized bed combustion technology is a kind of clear combustion technology, which has many advantages, such as excellence fuel flexibility, high combustion efficiency, low pollutant emission and good turndown capability etc. So, adopting fluidized bed combustion technology, retrofitting pulverized coal-fired boiler into fluidized bed boiler can realize pure burning various wastes or co-firing with coal, which should have great economic benefits and social benefits. And the application prospect of the method is also extensive. The State Key Laboratory of Coal Combustion has successfully retrofitted a 25t/h pulverized coal-fired boiler into circulating fluidized bed boiler with in-bed tubes and downward exhaust cyclone. The retrofitted boiler can burn mixture of coal and bagasse and the steam capacity reaches 35t/h. This paper presents the retrofitting measures and the operation status of the boiler after retrofitting.

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Rice husk bubbling fluidized bed combustion for amorphous silica synthesis

Journal of Environmental Chemical Engineering ◽

10.1016/j.jece.2016.03.049 ◽

2016 ◽

Vol 4 (2) ◽

pp. 2278-2290 ◽

Cited By ~ 9

Author(s):

Gabriel M. Faé Gomes ◽

Caterina Philipssen ◽

Eduardo K. Bard ◽

Leandro Dalla Zen ◽

Guilherme de Souza

Keyword(s):

Fluidized Bed ◽

Rice Husk ◽

Amorphous Silica ◽

Fluidized Bed Combustion ◽

Bubbling Fluidized Bed ◽

Silica Synthesis

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Reduction of Devolatilization Rate of Fuel During Bubbling Fluidized Bed Combustion Using Porous Bed Material

Chemical Engineering & Technology ◽

10.1002/1521-4125(200107)24:7<725::aid-ceat725>3.0.co;2-l ◽

2001 ◽

Vol 24 (7) ◽

pp. 725-733 ◽

Cited By ~ 10

Author(s):

H.-J. Franke ◽

T. Shimizu ◽

Y. Takano ◽

S. Hori ◽

M. Strziga ◽

...

Keyword(s):

Fluidized Bed ◽

Fluidized Bed Combustion ◽

Porous Bed ◽

Bubbling Fluidized Bed ◽

Bed Material

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Phosphorus-Rich Ash from Poultry Manure Combustion in a Fluidized Bed Reactor

Minerals ◽

10.3390/min11070785 ◽

2021 ◽

Vol 11 (7) ◽

pp. 785

Author(s):

Zdzisław Adamczyk ◽

Magdalena Cempa ◽

Barbara Białecka

Keyword(s):

Phase Composition ◽

Fluidized Bed ◽

Combustion Process ◽

Poultry Manure ◽

Raw Material ◽

Process Efficiency ◽

Chemical Components ◽

Bubbling Fluidized Bed ◽

Laboratory Reactor ◽

Size And Morphology

The aim of this study was to examine the physico-chemical and phase characteristics of ash obtained in the process of the combustion of Polish poultry manure in a laboratory reactor with a bubbling fluidized bed. Three experiments, differing in the grain size and morphology of the raw material, the method of its dosing and the type of fluidized bed, were carried out. The contents of the main chemical components and trace elements in the obtained ash samples were determined using WDXRF, and the phase composition was examined through the XRD method. The morphology and the chemical composition of grains in a given micro-area using the SEM/EDS method were also investigated. The highest concentration of phosphorus (from 28.07% wt. to 29.71% wt. as P2O5 equivalent), the highest proportion of amorphous substance (from 56.7% wt. to 59.0% wt.) and the lowest content of unburned organic substance (LOI from 6.42% to 9.16%) (i.e., the best process efficiency), was obtained for the experiment in which the starting bed was quartz sand and poultry manure was fed to the reactor in the form of pellets. It has been calculated that in this case, the amorphous phase contains more than half of the phosphorus. The method of carrying out the combustion process has a significant impact on the phase composition and, consequently, on the availability of phosphorus.

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