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%.

Measurement of Flow Rate of Droplets and Liquid Film in Venturi Scrubber

2016 ◽  
Author(s):  
Yasuhiro Nakao ◽  
Naoki Horiguchi ◽  
Hiroyuki Yoshida ◽  
Tetsuya Kanagawa ◽  
Akiko Kaneko ◽  
...  
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Gas Phase ◽  
Flow Rate ◽  
Interfacial Area ◽  
Decontamination Factor ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Radioactive Materials ◽  
Venturi Scrubber

As one of filtered venting systems which should be installed in light water reactors from viewpoint of protecting a containment vessel and suppressing the diffusion of radioactive materials, there is a system composed of venturi scrubbers. The radioactive materials in the contaminated gas are collected into liquid. By dispersed flow formed in the venturi scrubber, large interfacial area between liquid and gas was obtained, and large decontamination factor is realized. In evaluation for the decontamination performance of the venturi scrubber, interface of droplets and liquid film are important. However, there is a little knowledge about the interfacial area in the venturi scrubber for filtered venting. In this study, to obtain the interfacial area data, amount of the droplets and the liquid film in the venturi scrubber is evaluated by visualizing observation and sampling the liquid film at the outlet of the venturi scrubber. In the venturi scrubber, a pressure drop occurs in the throat part by the inflow of air from the compressor. Water flows from the tank by a pressure difference between a suctioned hole with head pressure and a throat part. An annular spray flow is then formed in the venturi scrubber. Therefore, the liquid flow rate changes according to the gas phase flow rate. To discharge separately the droplets and the liquid film, a rectangular separator is installed at the venturi scrubber outlet. The superficial gas phase flow rate is 25.2–292.3 m/s in the throat. As a result, the liquid film and the droplets through the wall were confirmed to be discharged separately by the separator. The ratio of the liquid film to the total amount of liquid is 80 to 95% and that of the droplets was estimated as 5 to 20%. However, the change of the liquid film thickness caused by the increase of gas phase flow rates was observed. When the liquid film thickness is large, it is possible that some liquid film flowing into the droplet side.

scholarly journals Comprehensive diagnosis of PCDD/F emission from three hazardous waste incinerators

2018 ◽  
Vol 5 (7) ◽  
pp. 172056 ◽  
Author(s):  
Xuan Cao ◽  
Longjie Ji ◽  
Xiaoqing Lin ◽  
William R. Stevens ◽  
Minghui Tang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Hazardous Waste ◽  
De Novo ◽  
Solid Phase ◽  
Bag Filter ◽  
Start Up ◽  
Equivalent Quantity ◽  
Comprehensive Diagnosis ◽  
Wet Scrubber ◽  
Waste Incinerators

Comprehensive diagnosis of polychlorinated dibenzo- p -dioxin and dibenzofuran (PCDD/F) emissions was systematically conducted on three hazardous waste incinerators (HWIs). Results indicated that PCDD/F mainly existed in the solid phase before the bag filter. This was especially true for higher chlorinated dioxin and furan congeners (hexa-, hepta- and octa-). The aged bag filters tended to increase the gas-phase PCDD/F. Emissions also increased due to PCDD/F desorption from circulated scrubbing solution and plastic packing media used in the wet scrubber. The PCDD/F concentrations were elevated during the start-up process, reaching up to 5.4 times higher than those measured during the normal operating period. The ratios of PCDFs/PCDDs revealed that the surface-catalysed de novo synthesis was the dominant pathway of PCDD/F formation. Installation of more efficient fabric filters, intermittent replacement of circulated scrubbing solution will result in reduced PCDD/F emission. Additionally, 2,3,4,7,8-PeCDF correlated well with the international toxic equivalent quantity (I-TEQ) value, which suggests that 2,3,4,7,8-PeCDF could act as an I-TEQ indicator.

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.

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 Simulation of Flow Behavior within a Venturi Scrubber

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
M. M. Toledo-Melchor ◽  
C. del C. Gutiérrez-Torres ◽  
J. A. Jiménez-Bernal ◽  
J. G. Barbosa-Saldaña ◽  
S. A. Martínez-Delgadillo ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Venturi Scrubber

The present work details the three-dimensional numerical simulation of single-phase and two-phase flow (air-water) in a venturi scrubber with an inlet and throat diameters of 250 and 122.5 mm, respectively. The dimensions and operating parameters correspond to industrial applications. The mass flow rate conditions were 0.483 kg/s, 0.736 kg/s, 0.861 kg/s, and 0.987 kg/s for the gas only simulation; the mass flow rate for the liquid was 0.013 kg/s and 0.038 kg/s. The gas flow was simulated in five geometries with different converging and diverging angles while the two-phase flow was only simulated for one geometry. The results obtained were validated with experimental data obtained by other researchers. The results show that the pressure drop depends significantly on the gas flow rate and that water flow rate does not have significant effects neither on the pressure drop nor on the fluid maximum velocity within the scrubber.

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.

Transient Numerical Modeling of Catalytic Channels

2007 ◽  
Author(s):  
P. M. Struk ◽  
D. L. Dietrich ◽  
F. J. Miller ◽  
J. S. T’ien
Keyword(s):  
Mass Transfer ◽  
Gas Phase ◽  
Heat Loss ◽  
Solid Phase ◽  
External Heat ◽  
Phase Model ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Mass Transfer Coefficients ◽  
First Case

This paper presents a transient model of catalytic combustion suitable for isolated channels and monolith reactors. The model is a “lumped” two-phase (gas and solid) model where the gas phase is quasi-steady relative to the transient solid. Axial diffusion is neglected in the gas phase; lateral diffusion, however, is accounted for using transfer coefficients. The solid phase includes axial heat conduction and external heat loss due to convection and radiation. The combustion process utilizes detailed gas and surface reaction models. The gas-phase model becomes a system of stiff ordinary differential equations while the solid phase reduces, after discretization, into a system of stiff ordinary differential-algebraic equations. The time evolution of the system came from alternating integrations of the quasi-steady gas and transient solid. This work outlines the numerical model and presents some sensitivity studies on important parameters including internal transfer coefficients, catalytic surface site density, and external heat-loss (if applicable). The model is compared to two experiments using CO fuel: (1) steady-state conversion through an isothermal platinum (Pt) tube and (2) transient propagation of a catalytic reaction inside a small Pt tube. The model requires internal mass-transfer resistance to match the experiments at lower residence times. Under mass-transport limited conditions, the model reasonably predicted exit conversion using global mass-transfer coefficients. Near light-off, the model results did not match the experiment precisely even after adjustment of mass-transfer coefficients. Agreement improved for the first case after adjusting the surface kinetics such that the net rate of CO adsorption increased compared to O2. The CO / O2 surface mechanism came from a sub-set of reactions in a popular CH4 / O2 mechanism. For the second case, predictions improved for lean conditions with increased external heat loss or adjustment of the kinetics as in the first case. Finally, the results show that different initial surface-species distribution leads to different steady-states under certain conditions. These results demonstrate the utility of a lumped two-phase model of a transient catalytic combustor with detailed chemistry.

Concentration Distribution Research of a Special DC Pulverized Coal Burner and Resistance Analysis

2012 ◽  
Author(s):  
Mo Yang ◽  
Chunsun Guo ◽  
Yuwen Zhang ◽  
Zhangyang Kang
Keyword(s):  
Gas Phase ◽  
Solid Phase ◽  
Pulverized Coal ◽  
Discrete Phase Model ◽  
Bias Effect ◽  
Two Phase ◽  
Discrete Phase ◽  
High Concentrations ◽  
Moderate Resistance ◽  
Pulverized Coal Burner

In this paper, a direct current (DC) anti-bias burner has been numerically simulated. This kind burner is combination of bias block and elbow bend and its bias block is located behind the bend. Effects of the bias block’s angle and location on coal distribution in the burner export are investigated. Euler-Lagrange approach is employed to study the gas-solid two-phase flow. The gas-phase is simulated using the RNG k-ε model and solid-phase is modeled using the discrete phase model (DPM). The results show that, installing a bias block behind the elbow can achieve a uniform distribution in outlet and the high concentrations region non-adherent. Relative to the location, the bias block angle changes is the main reason of generating resistance. When α = 25° L = 150mm, the distribution of pulverized coal of the burner outlet is the most uniform and the resistance is not large, which could satisfy the good anti-bias effect and moderate resistance loss at the same time.

Sign in / Sign up

Export Citation Format

Share Document