97/03004 Experimental results of thermal utilization of wastes and renewable raw materials in circulating fluidized-bed firings

The character of the Fly ash of Circulating Fluidized Bed Boiler (CFB Fly ash) is greatly different from that of Pulverized coal furnace for its high unburned carbon. In order to make effective use of CFB Fly ash in concrete, carbon content was decreased by simulated fluidized bed combustion in laboratory and a series of concerned experiments were carried out on CFB Fly ash. The experimental results indicate that CFB modification Fly ash is possible to be used in concrete to partially replaced cement. It is a valuable reference for CFB Fly ash technical engineers.

Download Full-text

Effect of Phosphorus on Desulfurization of Limestone during Sewage Sludge Combustion

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.3328 ◽

2012 ◽

Vol 518-523 ◽

pp. 3328-3334

Author(s):

Hai Meng Hou ◽

Shi Yuan Li ◽

Qing Gang Lu

Keyword(s):

Sewage Sludge ◽

Fluidized Bed ◽

Thermodynamic Analysis ◽

Circulating Fluidized Bed ◽

Experimental Results ◽

Test Rig ◽

Chemical Thermodynamic

Experiments of desulfurization of limestone during sewage sludge combustion with different phosphorus contents were conducted in a 15 kW circulating fluidized bed test rig to investigate the effect of phosphorus on desulfurization. Chemical thermodynamic analysis was performed to compare with the experimental results. Chemical thermodynamic analysis indicates that relatively high content of phosphorus in sewage sludge will affect desulfurization because calcium will first react with phosphorus and then the rest is available for reaction with sulfur, which agrees well with the experimental results. The experimental results also show that relatively high content of phosphorus in sewage sludge affects self-desulfurization of calcium in sewage sludge and desulfurization of limestone. The effect of phosphorus on desulfurization must be taken into account during sewage sludge combustion.

Download Full-text

Co-Combustion of Biomass and Coal in Circulating Fluidized Bed: Modeling and Validation

17th International Conference on Fluidized Bed Combustion ◽

10.1115/fbc2003-064 ◽

2003 ◽

Cited By ~ 3

Author(s):

Juan Ada´nez ◽

Luis F. de Diego ◽

Pilar Gaya´n ◽

Francisco Garci´a-Labiano ◽

Andre´s Cabanillas ◽

...

Keyword(s):

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Plug Flow ◽

Weighted Average ◽

Combustion Efficiency ◽

Operating Conditions ◽

Experimental Results ◽

Hydrodynamic Characteristics ◽

Particle Model ◽

Carbon Combustion

In this work carbon combustion efficiencies in circulating fluidized bed combustion (CFBC) when co-firing biomass and coal mixtures were studied. Experimental results were obtained from the combustion of two kind of coals with a forest residue (Pine bark) in a CBF pilot plant (0.3MWth) with 20-cm i.d. and 6.5-m height. The effect of operating conditions such as percentage of biomass in the feed, temperature, excess air, air velocity and percentage of secondary air on carbon combustion efficiency was studied. A mathematical model for the co-combustion of coal and biomass in a circulating fluidized bed boiler has been developed. The riser is divided in three zones with different hydrodynamic characteristics: bottom, splash and freeboard. The bottom bed has a constant voidage, determined by a modified two-phase theory. The solids are considered in perfect mixing and the gas in plug flow. The voidage in the splash region follows an exponential decay model. In the freeboard region, the solids and the gas are in plug flow, and a core-annulus structure is considered. Devolatilization of solid fuels is modeled with a particle reaction model which allows to determine the volatiles generation rate as a function of time and operating conditions. Kinetics of char combustion is modeled with the shrinking particle model with mixed control by chemical reaction and gas film diffusion, assuming that the ashes separate once formed. To consider that the char particles are a mixture of coal and biomass char particles, a weighted average combustion rate is defined taking into account the individual combustion rates. Population balances of char particles in the different regions were developed to calculate carbon concentrations. The developed model can predict the different gas concentrations along the riser, such as oxygen, SO2, CO, CH4, etc..., and the carbon combustion efficiency. The experimental results of carbon combustion efficiencies and gas emissions were compared with those predicted by the model and a good correlation was found for all the conditions used.

Download Full-text

Utilization of wastes derived from fluidized bed combustion and desulphurization of coals as sources of raw materials

Fuel and Energy Abstracts ◽

10.1016/s0140-6701(02)85514-x ◽

2002 ◽

Vol 43 (2) ◽

pp. 153

Keyword(s):

Fluidized Bed ◽

Raw Materials ◽

Fluidized Bed Combustion ◽

Utilization Of Wastes

Download Full-text

Experimental and Theoretical Information on Solid Flow in a Circulating Fluidized Bed

Journal of Energy Resources Technology ◽

10.1115/1.2835329 ◽

1995 ◽

Vol 117 (2) ◽

pp. 133-141

Author(s):

F. R. Steward ◽

M. F. Couturier ◽

S. Poolpol ◽

S. Wang

Keyword(s):

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Equations Of Motion ◽

Flow Patterns ◽

Operating Conditions ◽

Laboratory Scale ◽

Experimental Results ◽

Solid Flow ◽

Model Based ◽

Fundamental Equations

Data are presented on a laboratory-scale circulating fluidized bed for various column geometries, solid fluxes, and gas velocities. Particular attention is paid to the solid flux profiles under various operating conditions. A model based on the fundamental equations of motion has been developed to describe the flow patterns of the solids particles and gas within a circulating fluidized bed. The predictions of the model are compared with experimental results. The model predicts that instabilities at the base of the bed propagate up the column for significant distances before uniform flows of solids and gas are established.

Download Full-text

Influence of Fuel Type and Water Content Variation on Pollutant Emission Characteristics of a Biomass Circulating Fluidized Bed Boiler

Energies ◽

10.3390/en14185962 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5962

Author(s):

Jianjie He ◽

Shanjian Liu ◽

Di Yao ◽

Ranran Kong ◽

Yaya Liu

Keyword(s):

Moisture Content ◽

Fluidized Bed ◽

Flue Gas ◽

Power Plants ◽

Circulating Fluidized Bed ◽

Raw Materials ◽

Great Influence ◽

Water System ◽

Pollutant Emission ◽

Fuel Type

In general, the biomass raw materials burned by biomass power plants generally have the characteristics of variable fuel types, high moisture content, and high volatile content. In this paper, a 130 t/h biomass circulating fluidized bed (BCFB) model was established on the MWorks platform with Modelica language. The influence of biomass type changes on operation parameters, the corresponding steady-state characteristics, and the dynamic characteristics of the BCFB were carried out. The temperature corresponding to the combustion of pine was overall higher than that of the other fuels, and the flue gas from the combustion of pine had the highest concentration of SO2, up to 520.49 mg/Nm3. The flue gas from the combustion of pure cotton sticks had the highest concentration of NO, up to 254.34 mg/Nm3. The changes of fuel type and moisture content all have a great influence on the operation of BCFBs. The emission of pollutants was not only related to the element content of fuel, but also closely related to the furnace temperature. The fuel moisture content also indirectly affects the pollutant emission concentration and the steam-water system.

Download Full-text

Experimental Results for Oxy-fuel Combustion with High Oxygen Concentration in a 1MWth Pilot-scale Circulating Fluidized Bed

Energy Procedia ◽

10.1016/j.egypro.2014.11.039 ◽

2014 ◽

Vol 63 ◽

pp. 362-371 ◽

Cited By ~ 13

Author(s):

Haoyu Li ◽

Shiyuan Li ◽

Qiangqiang Ren ◽

Wei Li ◽

Mingxin Xu ◽

...

Keyword(s):

Fluidized Bed ◽

Oxygen Concentration ◽

Circulating Fluidized Bed ◽

Pilot Scale ◽

Fuel Combustion ◽

High Oxygen ◽

Experimental Results ◽

High Oxygen Concentration

Download Full-text

Internally circulating fluidized bed for continuous adsorption and desorption

International Journal of Multiphase Flow ◽

10.1016/s0301-9322(97)88169-4 ◽

1996 ◽

Vol 22 ◽

pp. 98

Author(s):

A Reichhold

Keyword(s):

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Adsorption And Desorption ◽

Continuous Adsorption

Download Full-text

Hydrogenolysis of glucose and fructose in glycol solutions over CuO-MgO-ZrO2 catalyst

Catalysis and petrochemistry ◽

10.15407/kataliz2020.30.048 ◽

2020 ◽

pp. 48-55

Author(s):

M.E. Sharanda ◽

◽

E.A. Bondarenko ◽

Keyword(s):

Ethylene Glycol ◽

Propylene Glycol ◽

Flow Reactor ◽

General Trend ◽

Raw Materials ◽

Reaction Products ◽

Renewable Raw Materials ◽

High Partial Pressure ◽

Zro2 Catalyst ◽

Phase Process

Ethylene glycol and propylene glycol are important representatives of polyols. On an industrial scale, they are obtained from petrochemical raw materials. Within a decade, significant efforts were made for the producing of polyols from biologically renewable raw materials - carbohydrates. The general trend for carbohydrate hydrogenolysis includes application of liquid-phase process with the use of modified metal-oxide catalysts, at 120-120 ° C and pressure of 3MPa or above. So high pressure is used for the reason to increase hydrogen solubility, and also due to the high partial pressure of low boiling solvents. We supposed that usage of high boiling solvents could allow hydrogenolysis to be performed at the lower pressure. Ethylene glycol and propylene glycol are of particular interest as such kind of solvent since they are both the main products of glucose hydrogenolysis. In this work, the process of hydrogenolysis of glucose and fructose over Cu / MgO-ZrO2 catalyst have been studied at temperature range of 160-200 °C and a pressure of 0.1-0.3 MPa in a flow reactor. The solvents were simultaneously the target products of the reaction - ethylene glycol and / or propylene glycol. Gas chromatography and 13C NMR were used for the reaction products identification. It was found that the solubility of glucose in propylene glycol is 21 % by weight, and in ethylene glycol 62% by weight. It was pointed out that the process of hydrogenolysis can take place at a pressure close to atmospheric. Under these conditions, the conversion of hexoses reaches 96-100 %. The reaction products are preferably propylene glycol and ethylene glycol. The total selectivity for C3-2 polyols is 90-94 %, that is higher than in the hydrogenolysis of glucose in aqueous solution.

Download Full-text