Co-Combustion of Pulverized Coal and Biomass in Fluidized Bed of Furnace

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Mitianiec Wladyslaw
Keyword(s):  
Open Source ◽  
Gas Phase ◽  
Flow Rate ◽  
Combustion Process ◽  
Theoretical Description ◽  
Pulverized Coal ◽  
Numerical Code ◽  
Two Phase ◽  
Inlet Flow Rate ◽  
Combustion Processes

Combustion processes of two fuels, pulverized coal and biomass, in furnaces take place at steady state. Combustion of condensed fuels involves one-way interfacial flux due to phenomena in the condensed phase (evaporation or pyrolysis) and reciprocal ones (heterogeneous combustion and gasification). Many of the species injected in the gas phase are later involved in gas phase combustion. This paper presents results of combustion process of two-phase charge contained coal and wetted biomass, where the carrier was the air with given flow rate. The furnace has three inlets with assumed inlet flow rate of coal, biomass, and air, and combustion process takes place in the furnace fluidized space. The simulation of such combustion process was carried out by numerical code of open source computational fluid dynamics (CFD) program code_saturne. For both fuels, the moist biomass with following mass contents: C = 53%, H = 5.8%, O = 37.62%, ash = 3.6, and mean diameter of molecules equal to 0.0008 m and pulverized coal with following mass contents: C = 76.65%, H = 5.16%, O = 9.9%, ash = 6.21%, and mean molecule diameter 0.000025 m were used. Devolatilization process with kinetic reactions was taken into account. Distribution of the main combustion product in furnace space is presented with disappearance of the molecules of fuels. This paper presents theoretical description of the two-phase charge, specification of the thermodynamic state of the charge in inlet boundaries and furnace space, and thermal parameters of solid fuel molecules obtained from the open source postprocessor paraview.

scholarly journals Numerical Study of Bubble Rising and Coalescence Characteristics under Flow Pulsation Based on Particle Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Ronghua Chen ◽  
Minghao Zhang ◽  
Kailun Guo ◽  
Dawei Zhao ◽  
Wenxi Tian ◽  
...  
Keyword(s):  
Flow Rate ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Numerical Study ◽  
Phase Flow ◽  
Flow Pulsation ◽  
Two Phase ◽  
Inlet Flow ◽  
Inlet Flow Rate ◽  
Bubble Rising

Two-phase flow instability may occur in nuclear reactor systems, which is often accompanied by periodic fluctuation in fluid flow rate. In this study, bubble rising and coalescence characteristics under inlet flow pulsation condition are analyzed based on the MPS-MAFL method. To begin with, the single bubble rising behavior under flow pulsation condition was simulated. The simulation results show that the bubble shape and rising velocity fluctuate periodically as same as the inlet flow rate. Additionally, the bubble pairs’ coalescence behavior under flow pulsation condition was simulated and compared with static condition results. It is found that the coalescence time of bubble pairs slightly increased under the pulsation condition, and then the bubbles will continue to pulsate with almost the same period as the inlet flow rate after coalescence. In view of these facts, this study could offer theory support and method basis to a better understanding of the two-phase flow configuration under flow pulsation condition.

scholarly journals Numerical simulation of the effect of different NaCl concent on boiler flame combustion process

2021 ◽  
Vol 2108 (1) ◽  
pp. 012097
Author(s):  
Zhihai Cheng ◽  
Jiahao Wang ◽  
Xinhai Han
Keyword(s):  
Alkali Metal ◽  
Radiation Heat Transfer ◽  
Combustion Process ◽  
Pulverized Coal ◽  
Combustion Model ◽  
Two Phase ◽  
Combustion Region ◽  
Zhundong Coal ◽  
High Alkali ◽  
Factsage Software

Abstract Zhundong coal has been widely concerned because of its high alkali metal content, which brings great danger to the combustion of boiler. Therefore, it is extremely necessary to study the laws and characteristics of alkali metal influencing combustion in the burning process of zhundong coal. A gas-solid two-phase flow combustion model of pulverized coal containing NaCl was established by using Fluent software and FactSage software in a hot experimental combustion furnace. The influence of different NaCl content in pulverized coal on pulverized coal combustion process was discussed. The results show that with the increase of NaCl content in pulverized coal from 0 to 1% and 2%, the flame center temperature in the furnace increases about 80°C and 120°C under the same coal content, so it can be concluded that the increase of NaCl content can promote the combustion process of pulverized coal in the furnace. At the same time, it can be calculated that, with the increase of NaCl content, the flame range of the combustion region inside the furnace increases by 1/3. Because NaCl is decomposed by heat during combustion to help combustion, and the radiation heat transfer increases, the flame radiation range inside the furnace will increase.

Optimized Gun Barrel Based on Numerical Simulation to Produced Oil With Low BSW Content

2020 ◽  
Author(s):  
Silvia Araujo Daza ◽  
Urbano Montañez Villamizar
Keyword(s):  
Flow Rate ◽  
Operating Conditions ◽  
Water Mixture ◽  
Two Phase ◽  
Ansys Fluent ◽  
Inlet Flow ◽  
Gun Barrel ◽  
Vof Model ◽  
Inlet Flow Rate ◽  
Computational Fluid Dynamics Cfd

Abstract This work presents the methodology and results of the optimization of the internals (Inlet distributor, oil and water collectors) of a 20,000 BPD (0.037 m3/s) gun-barrel tank starting from an existing design. Computational fluid dynamics (CFD) was applied to simulate and evaluate the performance of various internal configurations. These simulations were performed to determine the best configuration to ensure efficient separation of the oil-water mixture and oil with a low BSW content < 2% at the outlet. The simulations were carried out using the commercial software ANSYS Fluent under the two-phase flow VOF model and k-ε realizable turbulence model. Further CFD simulations were performed to evaluate the behavior of the gun barrel tank under different operating conditions (Different inlet flow rate) and to determine the maximum operation flow which allows obtaining the crude-oil with a maximum BSW content of 0.5%. From the simulation results, an operating curve (operating flow vs retention time) was constructed. This information allows, in practice, to identify the inlet flow rate based on the desired content of BSW in the separated oil.

Study of Co-Injection of Natural Gas and Pulverized Coal in Blast Furnace Under Pure Oxygen Environment

2008 ◽  
Author(s):  
Mingyan Gu ◽  
Jiaxin Li
Keyword(s):  
Numerical Simulation ◽  
Blast Furnace ◽  
Natural Gas ◽  
Combustion Process ◽  
Pulverized Coal ◽  
Pure Oxygen ◽  
Coke Combustion ◽  
Oxygen Gas ◽  
Combustion Processes ◽  
Developing Method

Using pure oxygen in blast furnace is a developing method in blast furnace in order to lower the emission of waste gases. Numerical simulation has been applied to analyze the combustion process of co-injection of natural gas (NG) and pulverized coal (PC) in a blast furnace while the blast is pure oxygen gas. The effect of injection NG and blast flow rate on the coal and coke combustion processes is examined. The predicted results provide a better understanding of reactions inside blast furnace.

Effect of Bubble Size and Angle of Tapered Upriser Pipe on the Effectiveness of a Two Phase Lifting Pump

2009 ◽  
Author(s):  
P. Hanafizadeh ◽  
M. H. Saidi ◽  
A. Zamiri ◽  
A. Karimi
Keyword(s):  
Gas Phase ◽  
Flow Rate ◽  
Bubble Size ◽  
Gas Flow ◽  
Bubble Diameter ◽  
Design Parameters ◽  
Two Phase ◽  
Bubble Distribution ◽  
Improved Performance ◽  
Different Diameters

Two phase lifting pumps are devices with the ability of lifting liquid phase by injecting the gas phase. Parameters which affect the performance of these pumps are divided into two groups. The first group contains design parameters such as diameter of the pipe, tapering angle of the upriser pipe and the submergence ratio which is the ratio of immersed length to the total length of the upriser. The second group includes operating parameters, such as the gas flow rate, bubble diameter, bubble distribution and inlet gas pressure. In this research, the performance of two phase lifting pump is investigated numerically for different submergence ratios and different diameter of the upriser pipe. For this purpose the two phase pump with a riser length of 914 mm and different diameters (6, 8 and 10 mm), and seven tapering angles (0°, 0.25°, 0.5°, 1°, 1.5°, 2° and 3°) are numerically modeled and analyzed. Different submergence ratios are used, namely: 0.4, 0.6 and 0.8. The numerical results are compared with the existing experimental data in the literature showing a reasonable agreement. The results indicate that decrease in size of the bubble diameter increases mass flow rate of liquid at constant submergence ratios. The present study reports the improved performance of this pump with decrease in bubble size and increase in angle of tapered upriser pipe. Moreover, the results show that the tapered upriser pipe with 3° tapering angle gives the highest efficiency at nearly all submergence ratios. Further, the highest efficiency of the pump is shown to be at the largest submergence ratio, namely 0.8.

scholarly journals Development of mathematical model for co-firing pulverized coal and biomass in experimental furnace

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 709-719 ◽  
Author(s):  
Aleksandar Milicevic ◽  
Srdjan Belosevic ◽  
Ivan Tomanovic ◽  
Nenad Crnomarkovic ◽  
Dragan Tucakovic
Keyword(s):  
Mathematical Model ◽  
Turbulent Transport ◽  
Combustion Process ◽  
Computer Code ◽  
Transport Processes ◽  
Pulverized Coal ◽  
Combustion Model ◽  
Two Phase ◽  
Processes And Reactions ◽  
Wide Range

A comprehensive mathematical model for prediction of turbulent transport processes and reactions during co-combustion of pulverized fuels in furnace fired by 150 kW swirl stabilized-burner has been developed. Numerical simulations have been carried out by using an in-house developed computer code, with Euler-Lagrangian approach to the two-phase flow modelling and sub-models for individual phases during complex combustion process: evaporation, devolatilization, combustion of volatiles, and char combustion. For sub-model of coal devolatilization the approach of Merrick is adopted, while for biomass devolatilization the combination models of Merrick, and of Xu and Tomita are selected. Products of devolatilization of both the pulverized coal and biomass are considered to contain the primary gaseous volatiles and tar, which further decomposes to secondary gaseous volatiles and residual soot. The residual soot in tar and carbon in coal and biomass char are oxidized directly, with ash remaining. For volatiles combustion the finite rate/eddy break-up model is chosen, while for char oxidation the combined kinetic-diffusion model is used. The comprehensive combustion model is validated against available experimental data from the case-study cylindrical furnace. The agreement of the simulations with the data for the main species in the furnace is quite good, while some discrepancies from experimental values are found in the core zone. The presented model is a good basis for further research of co-combustion processes and is able to provide analysis of wide range of pulverized fuels, i. e. coal and biomass. At the same time, the model is relatively simple numerical tool for effective and practical use.

scholarly journals Numerical tracking of sorbent particles and distribution during gas desulfurization in pulverized coal-fired furnace

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 759-769 ◽  
Author(s):  
Ivan Tomanovic ◽  
Srdjan Belosevic ◽  
Aleksandar Milicevic ◽  
Nenad Crnomarkovic ◽  
Dragan Tucakovic
Keyword(s):  
Gas Phase ◽  
Mutual Influence ◽  
Sulfur Removal ◽  
Pulverized Coal ◽  
Turbulent Dispersion ◽  
Boiler Furnace ◽  
Two Phase ◽  
Turbulence Modulation ◽  
Desulfurization Process ◽  
Sorbent Injection

Furnace sorbent injection for sulfur removal from flue gas presents a challenge, as the proper process optimization is of crucial importance in order to obtain both high sulfur removal rates and good sorbent utilization. In the simulations a two-phase gas-particle flow is considered. Pulverized coal and calcium-based sorbent particles motion is simulated inside of the boiler furnace. It is important to determine trajectories of particles in the furnace, in order to monitor the particles heat and concentration history. A two-way coupling of the phases is considered ? influence of the gas phase on the particles, and vice versa. Particle-to-particle collisions are neglected. Mutual influence of gas and dispersed phase is modeled by corresponding terms in the transport equations for gas phase and the equations describing the particles turbulent dispersion. Gas phase is modeled in Eulerian field, while the particles are tracked in Lagrangian field. Turbulence is modeled by the standard k-? model, with additional terms for turbulence modulation. Distribution, dispersion and residence time of sorbent particles in the furnace have a considerable influence on the desulfurization process. It was shown that, by proper organization of process, significant improvement considering emission reduction can be achieved.

scholarly journals Pengaruh Ukuran Partikulat Hasil Gasifikasi Batubara Terhadap Efisiensi Wet Scrubber

2020 ◽  
Vol 13 (3) ◽  
pp. 249-256
Author(s):  
Derina Paramitasari ◽  
Erbert Ferdy Destian ◽  
Mochammad Ismail
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Flow Rate ◽  
Solid Phase ◽  
Two Phase ◽  
Venturi Scrubber ◽  
Particle Size Analyzer ◽  
Particulate Size ◽  
Wet Scrubber ◽  
Wet Esp

Syngas dari gasifikasi batubara mengandung komponen pengotor seperti tar, char, H2O,  ash, NH3, H2S dan COS. Zat-zat pengotor tersebut dibagi mejadi dua fase, yaitu fase gas (uap) dan fase padatan (partikulat). Selanjutnya, syngas akan dibersihkan dari pengotornya menggunakan cyclone, wet scrubber dan wet ESP. Dalam penelitian ini, jenis wet scrubber yang digunakan adalah venturi scrubber. Efisiensi dari venturi scubber ini ditentukan oleh ukuran partikulat pengotor dalam syngas. Syngas dari cyclone dianalisa ukuran partikulatnya menggunakan Particle Size Analyzer dan didapatkan grup ukuran partikulat dalam mikrometer (%vol), yaitu 0 – 1 (8,81%), 1 – 2 (12,51%), 2 – 4 (27,33%), 4 – 6 (15,94%), 6 – 8 (10,25%), 8 – 10 (6,7%), 10 – 20 (10,66%), 20 – 40 (4,96%), 40 – 60 (2,6%), dan 60 – 80 (0,17%). Lalu, data tersebut dianalisa dengan debit (flow rate) dan fraksi massa umpan venturi scrubber, maka didapatkan hasil efisiensi venturi scrubber sebesar 97,48%.Syngas from coal gasifiation consist of various impurities such as tar, char, H2O, ash, NH3, H2S and COS. Those impurities can be classified into two phase groups, which are gas phase (includes vapor) and solid phase (particulates). After gasification, syngas will be purified or cleaned from its impurities with some equipments such as cyclone, wet scrubber and wet ESP. The wet scrubber type that is used in this research is venturi scrubber. The scrubber efficiency is determined by the amount of particulate in syngas. Particulate size in syngas from cyclone is analyzed using Particle Size Analyzer, to obtain data of particulate sizes in micrometer (%vol), which are yaitu 0 – 1 (8,81%), 1 – 2 (12,51%), 2 – 4 (27,33%), 4 – 6 (15,94%), 6 – 8 (10,25%), 8 – 10 (6,7%), 10 – 20 (10,66%), 20 – 40 (4,96%), 40 – 60 (2,6%), dan 60 – 80 (0,17%). Then, those data are calculated together with the flow rate and mass fraction of scrubber feed, to get venturi scrubber effficiency 97,48%.

Experimental Study on the Fluctuation Characteristics of Pressure Drop and Mass Flux of the Two-Phase Flow in Narrow Channel

2013 ◽  
Author(s):  
Deqi Chen ◽  
Qinghua Wang ◽  
Zhengang Duan ◽  
Liang-ming Pan
Keyword(s):  
Liquid Phase ◽  
Pressure Drop ◽  
Gas Phase ◽  
Flow Rate ◽  
Mass Flux ◽  
Gas Flow ◽  
Working Fluid ◽  
Phase Flow ◽  
Two Phase ◽  
Liquid Mass

In this paper the study focuses on a visual investigation on the gas-water two-phase flow in a vertical circular narrow channel with 2 mm inner diameter under atmospheric pressure. Experiments were carried out with different working conditions, including different gases as gas-phase working fluids such as nitrogen, air, carbon dioxide and argon, and the gas flow rate, Q, varied between 0 ml/s (single liquid phase flow) to 9.0 ml/s, and the liquid mass flux, G, varied between 581.3 kg/m2s to 3201.8 kg/m2s. The influence of liquid mass flux, gas flow rate as well as Eo number and Mo number (using these two non-dimensional parameters to specify the effect of gas-phase properties) on the fluctuation of pressure drop and mass flux were investigated in this study. It is found that the pressure drop increases along with increasing liquid-phase flow rate with identical other working conditions, and the corresponding flow patterns are slug flow even though the liquid-phase flow rates are different. However, the pressure drop decreases at first and then increases along with gas-phase flow rate, with constant liquid flow rate (liquid mass flux), and the corresponding flow patterns include slug flow, slug-annular flow and annular flow. Based on the experimental result, it is also found that the smaller Eo number and Mo number of the gas-phase working fluid, the smaller the fluctuations of the pressure drop and mass flux would be due to the gas-phase working fluid is different.

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