CFD MODEL TO ANALYZE SO2 ABSORPTION IN A SEAWATER DROPLET

2021 ◽  
Vol 161 (A4) ◽  
Author(s):  
M I Lamas ◽  
C G Rodriguez
Keyword(s):  
Droplet Diameter ◽  
Seawater Temperature ◽  
Liquid Temperature ◽  
Cfd Model ◽  
Gas Temperature ◽  
So2 Emissions ◽  
Initial Concentration ◽  
Marine Engines ◽  
So2 Absorption ◽  
So2 Concentration

In the recent years, seawater scrubbers have become an interesting option to reduce SO2 emissions in marine engines. In this regard, this paper proposes a numerical model to analyze SO2 absorption in seawater. A single seawater droplet was analyzed, and the developed model was used to predict the influence of several parameters on the desulphurization efficiency, such as the droplet diameter, SO2 concentration, alkalinity and temperature. It was found that a droplet of 200 μm initial diameter can absorb up to 1.77∙10-14 mol of S for the parameters analyzed, and this reduction improves when the alkalinity and SO2 concentration are increased and diameter, seawater temperature and gas temperature are reduced. Differences up to of 21.5%, 19.8%, 2.2% and 16.3% in the S reduction were obtaining varying the SO2 initial concentration, alkaline initial concentration, initial liquid temperature and initial gas temperature respectively.

CFD Model to Analyze SO2 Absorption in a Seawater Droplet

2019 ◽  
Vol 161 (A4) ◽  
Keyword(s):  
Droplet Diameter ◽  
Seawater Temperature ◽  
Liquid Temperature ◽  
Cfd Model ◽  
Gas Temperature ◽  
So2 Emissions ◽  
Initial Concentration ◽  
Marine Engines ◽  
So2 Absorption ◽  
So2 Concentration

In the recent years, seawater scrubbers have become an interesting option to reduce SO2 emissions in marine engines. In this regard, this paper proposes a numerical model to analyze SO2 absorption in seawater. A single seawater droplet was analyzed, and the developed model was used to predict the influence of several parameters on the desulphurization efficiency, such as the droplet diameter, SO2 concentration, alkalinity and temperature. It was found that a droplet of 200 μm initial diameter can absorb up to 1.77∙10-14 mol of S for the parameters analyzed, and this reduction improves when the alkalinity and SO2 concentration are increased and diameter, seawater temperature and gas temperature are reduced. Differences up to of 21.5%, 19.8%, 2.2% and 16.3% in the S reduction were obtaining varying the SO2 initial concentration, alkaline initial concentration, initial liquid temperature and initial gas temperature respectively.

Modelling Flue Gas Desulfurization Using Pyrolusite Pulp in a Jet Bubbling Reactor

2009 ◽  
Vol 610-613 ◽  
pp. 85-96 ◽  
Author(s):  
Jing Dong Zhao ◽  
Shi Jun Su ◽  
Nan Shan Ai ◽  
Xiao Fan Zhu
Keyword(s):  
Flue Gas ◽  
Ph Value ◽  
Scale Up ◽  
Absorption Efficiency ◽  
Flue Gas Desulfurization ◽  
Process Conditions ◽  
Gas Temperature ◽  
Transfer Coefficients ◽  
Set Up ◽  
So2 Absorption

A mathematical model for flue gas desulfurization using pyrolusite pulp in jet bubbling reactor (JBR) was described. Firstly, based on the concept of two stages mass balance with chemical reaction, two models were set up, for jet bubbling zone and rising bubble zone, respectively, according to the construction of JBR. The models consist of two coupling differential equations and were solved simultaneously by integral and separation of the variables. Then the SO2 absorption efficiency expression was developed, considering the great discrepancy existing between the gas-side mass transfer coefficients of the jet bubbling zone and gas bubble rising zone. The final expression associates SO2 absorption efficiency with process conditions and JBR structure parameters, which can give some instruction and guidance for the study of reactor operation process. Predicted results from the theoretical model, including effect of pH value of the pulp, flue gas temperature and inlet SO2 concentration of flue gas on SO2 absorption efficiency, were found to be in good agreement with experimental data obtained in a jet bubbling reactor. The model provides a basis for the process scale up and operating guide.

scholarly journals CFD Simulation Research on Agglomeration between Coal-fired Ash Fine Particulate and Atomized Droplets

2020 ◽  
Vol 165 ◽  
pp. 01006
Author(s):  
Yiquan Guo ◽  
Junying Zhang
Keyword(s):  
Power Plant ◽  
Flow Field ◽  
Cfd Simulation ◽  
Negative Impact ◽  
Droplet Diameter ◽  
Temperature Drop ◽  
Operating Conditions ◽  
Gas Temperature ◽  
Simulation Research ◽  
Agglomeration Process

In this paper, a collision model between atomized droplets of agglomeration solution and particles is established. On this basis, the effects of flue gas temperature, atomized droplet diameter and other factors on the particle agglomeration process are studied. In addition, the evaporation model of agglomeration solution in the flue of a power plant is established for the coal-fired unit of power plant. Through CFD software, the variation of flow field velocity, temperature and pressure in the flue is simulated to determine whether the chemical agglomeration technology has negative impact on the actual operating conditions of the power plant. The simulation results show that the velocity and pressure of the flow field in the flue have no obvious change after the agglomerating agent is injected. Besides, the temperature drop of about 7°C. The droplets evaporate completely at a distance of 7-8 m after spraying. The evaporation time of droplets is within 1.6 s.

Validation of Mist/Steam Cooling CFD Model in a Horizontal Tube

2008 ◽  
Author(s):  
T. S. Dhanasekaran ◽  
Ting Wang
Keyword(s):  
Gas Turbine ◽  
Droplet Diameter ◽  
Turbulence Models ◽  
Horizontal Tube ◽  
Working Environment ◽  
Cfd Model ◽  
Wall Film ◽  
Cooling Enhancement ◽  
Steam Cooling ◽  
Uniform Droplets

Mist cooling concept has been considered for cooling turbine airfoils for many years. This concept has been proven experimentally as an effective method to significantly enhance the cooling effectiveness with several fundamental studies in the laboratory under low pressure and temperature conditions. However, it is not certain the same performance can be harnessed in the real gas turbine environment under the condition of elevated temperature, pressure, heat flux, and Reynolds number. This paper aims at validating a CFD model against experimental results in a circular tube and then applies the validated CFD model to simulate mist/steam cooling performance at elevated gas turbine working conditions. The results show that the standard k-ε and a RSM turbulence models are the best-suited model for this application. The mist with smaller droplet diameter is found achieving higher cooling enhancement than the flows with bigger droplets, while mist with a distributed droplet size matches the data slightest better than with uniform droplets. Both the wall-film and the reflect droplet boundary conditions are employed and their effects on the cooling result is not significant at the studied cases. The validated CFD model can predict the wall temperature within 2% in steam-only flow and 5% in the mist/steam flow. Applying the calibrated CFD model to the actual gas turbine working environment shows that the mist/steam cooling technique could harness an average 50–100% cooling enhancement.

Numerical Study the NOx Emission Characteristics of 600MW Opposed Swirling Coal-Fired Utility Boiler

2014 ◽  
Vol 1010-1012 ◽  
pp. 847-855
Author(s):  
Ya Ming Liu ◽  
Fang Yong Li ◽  
Qi Sheng Xu
Keyword(s):  
Fly Ash ◽  
Carbon Content ◽  
Residence Time ◽  
Flue Gas ◽  
Pulverized Coal ◽  
Nox Emission ◽  
Emission Characteristics ◽  
Cfd Model ◽  
Gas Temperature ◽  
Coal Particles

In this paper, a computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established to numerically study the NOx emission characteristics under different ratios of over fire air (OFA) and modes of in-service burner layers. The current CFD model had adopted a chemical percolation devolatilization (CPD) model and been validated by comparing the simulated results with the experimental data. The numerical simulation results show that, with increasing the ratio of OFA, the carbon content in fly-ash increase somewhat linearly and the NOx emission reduce significantly, and the OFA ratio of 30% is optimal with higher burnout of pulverized coal and lower NOx emission. The different in-service burner layer modes have different influences on the residence time of the pulverized-coal particles, effect of air staging in the burner region and flue gas temperature at the exit of the lower furnace. Stopping the upper burner layers can increases the residence time of the pulverized-coal particles, resulting in the reduction of the carbon content in the fly ash and the increase of the pulverized-coal burnout. The flue gas temperature at the exit of the lower furnace can also decrease, which would be helpful to reducing the slagging tendency on the surfaces of the platen superheaters.

scholarly journals Enhanced SO2 Absorption Capacity of Sodium Citrate Using Sodium Humate

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 865
Author(s):  
Zhiguo Sun ◽  
Yue Zhou ◽  
Shichao Jia ◽  
Yaru Wang ◽  
Dazhan Jiang ◽  
...  
Keyword(s):  
Gas Flow ◽  
Sodium Citrate ◽  
Absorption Capacity ◽  
Sodium Humate ◽  
So2 Adsorption ◽  
Synergistic Mechanism ◽  
Absorption Performance ◽  
Desulfurization Efficiency ◽  
So2 Absorption ◽  
So2 Concentration

A novel method of improving the SO2 absorption performance of sodium citrate (Ci-Na) using sodium humate (HA–Na) as an additive was put forward. The influence of different Ci-Na concentration, inlet SO2 concentration and gas flow rate on desulfurization performance were studied. The synergistic mechanism of SO2 absorption by HA–Na and Ci-Na was also analyzed. The consequence shows that the efficiency of SO2 absorption by Ci-Na is above 90% and the desulfurization time added with the Ci-Na concentration rising from 0.01 to 0.1 mol/L. Both the desulfurization efficiency and time may increase with the adding of HA–Na quality in Ci-Na solution. Due to adding HA–Na, the desulfurization efficiency of Ci-Na increased from 90% to 99% and the desulfurization time increased from 40 to 55 min. Under the optimum conditions, the desulfurization time of Ci-Na can exceed 70 min because of adding HA–Na, which is nearly doubled. The growth of inlet SO2 concentration has little effect on the desulfurization efficiency. The SO2 adsorption efficiency decreases with the increase of inlet flow gas. The presence of O2 improves the SO2 removal efficiency and prolongs the desulfurization time. Therefore, HA–Na plays a key role during SO2 absorption and can dramatically enhance the SO2 adsorption performance of Ci-Na solution.

scholarly journals A Non-invasive Method of Marine Engines Fuel System Diagnostics

2020 ◽  
Vol 3 (3) ◽  
pp. 381-388
Author(s):  
Andrej Grzadziela ◽  
Marcin Kluczyk
Keyword(s):  
Fuel Injection ◽  
Technical Condition ◽  
Gas Temperature ◽  
Non Invasive ◽  
Medium Speed ◽  
Marine Engines ◽  
Invasive Method ◽  
Cause Of Failure ◽  
Vibration Tests ◽  
Small Engines

Small naval vessels are equipped with high- and medium-speed engines with low diagnostic compliance. Faults in fuel installations are the most common cause of failure or inability to perform operational scenarios adequately. Identification of injector damage is severe as small engines are not equipped with indicators and thermocouples to measure the overall exhaust gas temperature in the exhaust manifold. The paper presents a vibration method for assessing the technical condition of a fuel installation. The proposed method is non-invasive and allows the indication of a damaged injector within a relatively short time. The paper presents simulation results verified with stand-bed tests. The research aimed to show the sensitivity and uniqueness of vibration symptoms to changes in the technical condition of fuel injection pumps. The conducted experiment confirmed the possibility of using vibration tests in the professional diagnostics of the fuel installation. These results are essential for the use of marine engines that do not have indicator valves.

Corrosion Study and Modification of Superheater Tubes in a Large Mass Burn WTE Boiler (Abstract)

2005 ◽  
Author(s):  
Greg Epelbaum
Keyword(s):  
Flue Gas ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Large Mass ◽  
Operating Conditions ◽  
Cfd Model ◽  
Gas Temperature ◽  
Unique Problem ◽  
Flux Flow ◽  
Tube Metal

Essex County Resource Recovery Facility (one of American Ref-Fuel Company’s six operating plants) has processing MSW capacity of approximately 2700 TPD and about 60% of this waste comes from NY City. Therefore, availability of the Essex plant boilers is very important not only for the company’s financial performance, it is also critical for the overall garbage disposal situation in the NYC Metropolitan area. One of the main factors affecting plant availability is boiler unscheduled downtime. The most recent data show that approximately 85% of Essex boilers unscheduled downtime is caused by tube failures, the majority of which occur in the superheater tubes. These tube failures are almost exclusively caused by fireside tube metal wastage driven by complicated mechanisms of corrosion in combination with local erosion. The corrosion is caused by chloride salts in the slag that deposits on the boiler tubes, coupled with high temperatures of flue gas going through the boiler. Corrosion rates are known to be very sensitive to flue gas temperature, tube metal temperature, heat flux, flow distribution. Erosion is typically caused by high velocities and flyash particle loading and trajectories. Extensive research revealed that in addition to this typical to WTE boiler corrosion/erosion mechanism, Essex boiler superheater tubes experienced a unique problem, resulting in tube overheating, accelerated wastage, and ultimate failure. In order to address this problem a modification plan was developed, which comprised several redesign options. A specially developed Three-dimensional Computational Fluid Dynamics (3-D CFD) model was utilized for comprehensive technical evaluation of the considered design options and for predicted performance simulations of the selected design at different operating conditions. The economical analysis, conducted in conjunction with the superheater redesign, provided financial justification for this project. The project has been recently executed, and field data collection is still in progress. Some preliminary data analyses have been performed. They have shown that the boiler performance after superheater modification is very close to the predicted target simulated by the CFD model. The plant and the company are already measuring financial benefits as a result of this project, the initial phase of which is presented in this paper.

Temperature Distribution within a Compressed Gas Cylinder during Fast Filling

2006 ◽  
Vol 15-17 ◽  
pp. 281-286
Author(s):  
C.J.B. Dicken ◽  
W. Mérida
Keyword(s):  
Temperature Sensor ◽  
Local Measurement ◽  
Cfd Model ◽  
Gas Temperature ◽  
Optimum Location ◽  
Governing Equations ◽  
Real Gas ◽  
Gas Cylinder ◽  
Compressed Gas ◽  
Real Gas Effects

Currently, pressurized gas is the leading technology for vehicular on-board hydrogen storage. During refueling, the hydrogen is expanded from the high-pressure fueling station cylinders, into the “empty” vehicle cylinder. The mass of the gas inside a cylinder can be calculated from the knowledge of the pressure and average gas temperature. However, during the fill process, the compression of the gas inside the cylinder leads to a rapid increase in temperature, this phenomenon along with the continuous introduction of cooler gas creates an evolving spatial distribution of gas temperature within the cylinder. In order to determine a correlation between the massaveraged gas temperature and local measurement of gas temperature, this study presents a CFD model of the filling of a hydrogen compressed gas cylinder. The model developed in this study is 2D and axi-symmetric, and solves the governing equations for compressible, unsteady, viscous turbulent flow. The model incorporates real gas effects, convective heat transfer from the gas to the cylinder walls and conduction through the cylinder walls to ambient. The results of the model show a large spatial variation of gas temperature within the cylinder during filling. The modeling results also help to identify the optimum location for the onboard gas temperature sensor such that the local measurement best represents the mass-averaged temperature of the gas within the cylinder. Hence allowing for the calculation of the mass of gas within the cylinder without using an expensive flow meter.

Modeling and Simulation of Sulfur Dioxide Abatement with Ammonia Absorbent in the Spray Scrubber

2012 ◽  
Vol 599 ◽  
pp. 404-411 ◽  
Author(s):  
Yong Jia
Keyword(s):  
Flue Gas ◽  
Operating Conditions ◽  
Flue Gas Desulfurization ◽  
Gas Velocity ◽  
Desulfurization Process ◽  
Spray Scrubber ◽  
Influence Of Ph ◽  
So2 Absorption ◽  
Gas Ratio ◽  
So2 Concentration

In this paper, a model of ammonia-based wet flue gas desulfurization system was developed to simulate the process of absorption of SO2 and oxidation of total sulfite. The influence of pH, liquid-gas ratio, flue gas velocity and SO2 concentration on the desulfurization process were analyzed. The calculated desulfurization efficiency of the ammonia-based WFGD system for 2×210 t•h-1 boilers unit in China were compared to that of corresponding measured ones. The results show that the simulated values agreed well with the measured values for the operating conditions of pH, liquid/gas ratio and SO2 concentration. Corresponding amount of air needed for oxidation of total sulfite formed in SO2 absorption process was also calculated.

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