scholarly journals Sulfur Conversion of Mixed Coal and Gangue during Combustion in a CFB Boiler

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 553
Author(s):  
Lizheng Zhao ◽  
Yanfei Du ◽  
Yusen Zeng ◽  
Zhizhong Kang ◽  
Baomin Sun
Keyword(s):  
Fluidized Bed ◽  
Test Bench ◽  
Solid Phase ◽  
Thermodynamic Simulation ◽  
Earth Metal ◽  
Simulation Software ◽  
Transformation Mechanism ◽  
Metal Sulfate ◽  
Cfb Boiler ◽  
Sulfur Containing

The construction of a power plant using a 660 MWe supercritical circulating fluidized bed (CFB) boiler with co-combustion of coal and gangue has been proposed in China. Therefore, this study simulated the distribution law and transformation mechanism of sulfur-containing phases using three low-calorific samples of gangue and coal mixtures under different conditions, based on the thermodynamic simulation software HSC Chemistry. The results showed that sulfur low in calorific value coal is mainly converted into gas phase SO2, solid phase alkali metal sulfate (Na2SO4 and K2SO4), and alkaline earth metal sulfate (CaSO4 and MgSO4) in an oxidizing atmosphere. Under a reductive atmosphere, sulfur in coal is mainly converted into gaseous H2S, COS (Carbon oxysulfide), and solid FeSx. With an increase in the O/C ratio, the distribution curve of sulfur-containing substances contracted to lower temperatures. It was established that the sulfur fixation capacity of coal ash depends on the relative amounts of basic oxides and sulfur present in it. Relevant conclusions were also verified and compared to those of the laboratory small-fluidized bed test bench and the 3 MWth CFB combustion test bench.

Deep-ultraviolet transparent alkali metal-rare earth metal sulfate NaY(SO4)2.H2O as a nonlinear optical crystal: synthesis and characterization

CrystEngComm ◽  
2021 ◽  
Author(s):  
Chao Wu ◽  
Lin Lin ◽  
Tianhui Wu ◽  
Zhipeng Huang ◽  
Chi Zhang
Keyword(s):  
Rare Earth ◽  
Alkali Metal ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Synthesis And Characterization ◽  
Nonlinear Optical Crystal ◽  
Metal Sulfate ◽  
Deep Ultraviolet ◽  
Crystal Synthesis ◽  
Optical Crystal

A new alkali metal-rare earth metal sulfate with the formula NaY(SO4)2.H2O has been synthesized using a mild hydrothermal method. It crystallizes in the noncentrosymmetric trigonal space group P3121 (No. 152)...

Preparation of functional magnetic porous organic polymer as sorbents for mercury speciation followed by HPLC-ICP-MS analysis

2021 ◽  
Author(s):  
Yifeng He ◽  
Man He ◽  
Beibei Chen ◽  
Bin Hu
Keyword(s):  
High Performance ◽  
Solid Phase ◽  
Magnetic Solid Phase Extraction ◽  
Mercury Speciation ◽  
Organic Polymer ◽  
Phase Extraction ◽  
Porous Organic Polymer ◽  
Icp Ms ◽  
Magnetic Solid ◽  
Sulfur Containing

A novel sulfur-containing functional core-shell magnetic porous organic polymer (Fe3O4@BD-TpMA-S-SH MOPs) was synthesized as magnetic solid phase extraction (MSPE) sorbent for mercury speciation followed by high performance liquid chromatography (HPLC)...

Performance evaluation of a supercritical circulating fluidized bed boiler for power generation under flexible operation

2021 ◽  
pp. 095765092199396
Author(s):  
Matteo Bruzzone ◽  
Silvia Ravelli
Keyword(s):  
Power Generation ◽  
Fluidized Bed ◽  
High Performance ◽  
Circulating Fluidized Bed ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Hard Coal ◽  
Cfb Boiler ◽  
Power Cycles ◽  
Commercial Code

It is well known that the Łagisza power plant in Poland is the world’s first supercritical circulating fluidized bed (CFB) boiler, whose commercial operation started on June 2009. It has attracted a great deal of interest and operational data are publicly available, therefore it has been chosen as the object of the present study aimed at assessing load and fuel flexibility of supercritical CFB plants. First, the thermal cycle was modelled, by means of the commercial code Thermoflex®, at nominal and part load conditions for validation purposes. After having verified the validity of the applied modelling and simulation tool, the advantage of having supercritical steam combined with CFB boiler over subcritical steam and pulverized coal (PC) boiler, respectively, was quantified in terms of electric efficiency. As a next step, the designed fuel, i.e. locally mined hard coal, was replaced with biomass: 100% biomass firing was taken into account in the case of subcritical CFB boiler whereas the maximum share of biomass with coal was set at 50% with supercritical CFB boiler, consistently with the guidelines provided by the world leading manufacturers of CFB units. A broad range of biomass types was tested to conceive mixtures of fuel capable of preserving quite high performance, despite the energy consumption in pretreatment. However, the overall efficiency penalty, due to biomass co-firing, was found to potentially undermine the benefit of supercritical steam conditions compared to conventional subcritical power cycles. Indeed, the use of low-quality biomass in thermal power generation based on steam Rankine cycle may frustrate efforts to push the steam cycle boundaries.

3D Numerical Simulation of Polydisperse Pressurized Gas-Solid Fluidized Bed

2011 ◽  
Author(s):  
P. Fede ◽  
O. Simonin ◽  
I. Ghouila
Keyword(s):  
Numerical Simulation ◽  
Fluidized Bed ◽  
Ethylene Polymerization ◽  
Solid Phase ◽  
Three Dimensional ◽  
Gas Velocity ◽  
Particle Segregation ◽  
3D Numerical Simulation ◽  
Model Predictions ◽  
The Mean

Three dimensional unsteady numerical simulations of dense pressurized polydisperse fluidized bed have been carried out. The geometry is a medium-scale industrial pilot for ethylene polymerization. The numerical simulation have been performed with a polydisperse collision model. The consistency of the polydisperse model predictions with the monodisperse ones is shown. The results show that the pressure distribution and the mean vertical gas velocity are not modified by polydispersion of the solid phase. In contrast, the solid particle species are not identically distributed in the fluidized bed indicating the presence of particle segregation.

scholarly journals Comparison of solid phase closure models in Eulerian-Eulerian simulations of a circulating fluidized bed riser

2019 ◽  
Vol 195 ◽  
pp. 39-50 ◽  
Author(s):  
Markku Nikku ◽  
Alexander Daikeler ◽  
Alexander Stroh ◽  
Kari Myöhänen
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Solid Phase ◽  
Closure Models

scholarly journals Experimental and Theoretical Study of the Axial Distribution of Solid Phase Particles in a Fluidized Bed

2021 ◽  
Vol 64 (4) ◽  
pp. 349-362
Author(s):  
A. V. Mitrofanov ◽  
V. E. Mizonov ◽  
N. S. Shpeynova ◽  
S. V. Vasilevich ◽  
N. K. Kasatkina
Keyword(s):  
Fluidized Bed ◽  
Field Experiments ◽  
Solid Phase ◽  
Cell Model ◽  
Experimental Studies ◽  
Parametric Identification ◽  
Resistance Coefficient ◽  
Model Material ◽  
Spherical Particles ◽  
Axial Distribution

The article presents the results of computational and experimental studies of the distribution of a model material (plastic spherical particles with a size of 6 mm) along the height of a laboratory two-dimensional apparatus of the fluidized bed of the periodic principle of action. To experimentally determine the distribution of the solid phase over the height of the apparatus, digital photographs of the fluidized bed were taken, which were then analyzed using an algorithm that had been specially developed for this purpose. The algorithm involved splitting the image by height into separate rectangular areas, identifying the particles and counting their number in each of these areas. Numerical experiments were performed using the previously proposed one-dimensional cell model of the fluidization process, constructed on the basis of the mathematical apparatus of the theory of Markov chains with discrete space and time. The design scheme of the model assumes the spatial decomposition of the layer in height into individual elements of small finite sizes. Thus, the numerically obtained results qualitatively corresponded to the full-scale field experiment that had been set up. To ensure the quantitative reliability of the calculated forecasts, a parametric identification of the model was performed using known empirical dependencies to calculate the particle resistance coefficient and estimate the coefficient of their macrodiffusion. A comparison of the results of numerical and field experiments made us possible to identify the most productive empirical dependencies that correspond to the cellular scheme of modeling the process. The resulting physical and mathematical model has a high predictive efficiency and can be used for engineering calculations of devices with a fluidized bed, as well as for setting and solving problems of optimal control of technological processes in these devices for various target functions.

Improved throttle valve modeling for spark-ignition engine simulations

2018 ◽  
Vol 233 (6) ◽  
pp. 1614-1622 ◽  
Author(s):  
Elie Haddad ◽  
David Chalet ◽  
Pascal Chesse
Keyword(s):  
Internal Combustion Engine ◽  
Discharge Coefficient ◽  
Test Bench ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Simulation Software ◽  
Spark Ignition Engine ◽  
Engine Test ◽  
Engine Simulation ◽  
Throttle Valve

Automotive manufacturers nowadays are constantly working on improving their internal combustion engines’ performance by reducing the fuel consumption and emissions, without compromising the power generated. Manufacturers are therefore relying on virtual engine models that can be run on simulation software in order to reduce the amount of time and costs needed, in comparison with experiments done on engine test benches. One important element of the intake system of an internal combustion engine is the throttle valve, which defines the amount of air reaching the plenum before being drawn into the cylinders. This article discusses a widely used model for the estimation of air flow rate through the throttle valve in an internal combustion engine simulation. Experiments have been conducted on an isolated throttle valve test bench in order to understand the influence of different factors on the model’s discharge coefficient. These experiments showed that the discharge coefficient varies with the pressure ratio across the throttle valve and with its angle. Furthermore, for each angle, this variation can be approximated with a linear model composed of two parameters: the slope and the Y-Intercept. These parameters are calibrated for different throttle valve angles. This calibration can be done using automotive manufacturers’ standard engine test fields that are often available. This model is then introduced into an engine simulation model, and the results are compared to the experimental data of a turbocharged engine test bench for validation. They are also compared with a standard discharge coefficient model that varies only with the throttle valve angle. The results show that the new model for the discharge coefficient reduces mass flow estimation errors and allows expanding the applications of the throttle valve isentropic nozzle model.

scholarly journals Feasibility Study of Using Carbide Slag as In-Bed Desulfurizer in Circulating Fluidized Bed Boiler

2019 ◽  
Vol 9 (21) ◽  
pp. 4517 ◽  
Author(s):  
Zhong Huang ◽  
Jimiao Long ◽  
Lei Deng ◽  
Defu Che
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Molar Fraction ◽  
So2 Emissions ◽  
Cfb Boiler ◽  
Carbide Slag ◽  
Desulfurization Efficiency ◽  
Sintering Resistance ◽  
Pilot Tests

Carbide slag is a waste residue during the production of acetylene. Due to its high content of Ca(OH)2, carbide slag becomes a potential alternative to limestone as the in-bed desulfurizer of circulating fluidized bed (CFB) boilers. In this study, the calcination and sulfation characteristics of carbide slag were investigated by three different facilities, thermogravimetric analyzer (TGA), 1 MWth pilot CFB boiler, and 690 t·h−1 CFB boiler. Pore structures and sulfation behaviors of carbide slag and limestone were investigated for the sake of comparison. The results showed that carbide slag has a lower calcination temperature than limestone. Its calcined product has a better pore structure and desulfurization activity. The carbide slag exhibited a higher desulfurization efficiency than the limestone in the pilot tests. The SO2 emission concentration showed a downward trend with the increase of molar fraction of carbide slag in the desulfurizer. Meanwhile, carbide slag had a better sintering-resistance property, which makes it possible to effectively reduce SO2 emissions even at high combustion temperatures (>910 °C). While the field test results were similar to that of the pilot tests, the desulfurization efficiency of carbide slag with the same Ca/S mole ratio was higher than that of limestone. The fine size of carbide slag particles and the lower separation efficiency of the cyclone on the 690 t·h−1 boiler left the carbide slag with insufficient residence time in the furnace. Therefore, it is necessary to ensure a high separation efficiency of the cyclone if the carbide slag is used as an alternative desulfurizer in furnace.

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