scholarly journals Reference document for LANL stack sampling and ANSI N13.1 (Article) Gielow RL and McNamee MR 1993. Numerical Flue Gas Flow Modeling for Continuous Emissions Monitoring Applications. EPRI CEM Users Group Meeting. Baltimore. RP1961-13.

2021 ◽  
Author(s):  
Murray Moore ◽  
John Glissmeyer ◽  
J. Barnett
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Group Meeting ◽  
Flow Modeling ◽  
Monitoring Applications ◽  
Reference Document

Improving Semi-Dry Scrubber Performance Through Gas Flow Modeling

2005 ◽  
Author(s):  
Nikita Gorsky ◽  
C. F. Peter Bowen
Keyword(s):  
Velocity Distribution ◽  
Residence Time ◽  
Flue Gas ◽  
Gas Flow ◽  
Waste To Energy ◽  
Distribution Data ◽  
Outlet Temperature ◽  
Flow Modeling ◽  
Before And After ◽  
Distribution Testing

Poor flue gas flow distribution in the semi-dry scrubbers used in Waste-to-Energy facilities can cause reduced residence time for lime slurry spray droplet evaporation and subsequent “wet carryover” resulting in solids deposits on the scrubber vessel walls and ductwork and also baghouse bag blinding. In addition to promoting corrosion, the removal of deposits during boiler outages is very labor intensive. This paper identifies how gas flow modeling conducted in conjunction with Nels Consulting Services, Inc. on several different types of scrubbers at Covanta Energy’s Waste-to-Energy facilities resulted in modifications which increased the actual flue gas residence time, considerably reduced the solids deposits (scale) and associated maintenance costs, and in some cases reduced the pressure drop across the scrubbers and baghouses. The data presented includes typical model study velocity distribution data (before and after the modifications), vessel sketches, and photographs. Associated work included in-field scrubber outlet duct temperature and velocity distribution testing. The results of the in-field scrubber outlet temperature distribution testing, done both before and after the scrubber modifications, confirmed the improvements numerically by showing reduced flue gas temperature variation in the scrubber outlet duct.

scholarly journals Effect of Flue Gases’ Corrosive Components on the Degradation Process of Evaporator Tubes

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3860
Author(s):  
Mária Hagarová ◽  
Milan Vaško ◽  
Miroslav Pástor ◽  
Gabriela Baranová ◽  
Miloš Matvija
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Gas Flow ◽  
Degradation Process ◽  
Flue Gases ◽  
Saturated Steam ◽  
Mineral Salts ◽  
Related Factors ◽  
Local Overheating ◽  
Inner Surface

Corrosion of boiler tubes remains an operational and economic limitation in municipal waste power plants. The understanding of the nature, mechanism, and related factors can help reduce the degradation process caused by corrosion. The chlorine content in the fuel has a significant effect on the production of gaseous components (e.g., HCl) and condensed phases on the chloride base. This study aimed to analyze the effects of flue gases on the outer surface and saturated steam on the inner surface of the evaporator tube. The influence of gaseous chlorides and sulfates or their deposits on the course and intensity of corrosion was observed. The salt melts reacted with the steel surface facing the flue gas flow and increased the thickness of the oxide layer up to a maximum of 30 mm. On the surface not facing the flue gas flow, they disrupted the corrosive layer, reduced its adhesion, and exposed the metal surface. Beneath the massive deposits, a local overheating of the inner surface of the evaporator tubes occurred, which resulted in the release of the protective magnetite layer from the surface. Ash deposits reduce the boiler’s thermal efficiency because they act as a thermal resistor for heat transfer between the flue gases and the working medium in the pipes. The effect of insufficient feedwater treatment was evinced in the presence of mineral salts in the corrosion layer on the inner surface of the tube.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

Gas flow modeling for focused ion beam (FIB) repair processes

2004 ◽  
Author(s):  
Mohamed S. El-Morsi ◽  
Alexander C. Wei ◽  
Gregory F. Nellis ◽  
Roxann L. Engelstad ◽  
Sybren Sijbrandij ◽  
...  
Keyword(s):  
Gas Flow ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Flow Modeling ◽  
Repair Processes

High Flue Gas Flow Rate Tests for Removal and Recovery of Carbon Dioxide under Power Plant Effluent Gas Conditions

2004 ◽  
Vol 30 (6) ◽  
pp. 758-761
Author(s):  
Tomio MIMURA ◽  
Yasuyuki YAGI ◽  
Masaki IIJIMA ◽  
Ryuji YOSIYAMA ◽  
Takahito YONEKAWA
Keyword(s):  
Carbon Dioxide ◽  
Power Plant ◽  
Flow Rate ◽  
Flue Gas ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Power Plant Effluent ◽  
Removal And Recovery

A Novel Design for Reduction of Ammonium Bisulfate Deposition in the Rotary Air Preheater

2018 ◽  
Author(s):  
Yufan Bu ◽  
Limin Wang ◽  
Xiaoyang Wei ◽  
Lei Deng ◽  
Defu Che
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Catalytic Reduction ◽  
Operating Cost ◽  
Reaction Chamber ◽  
Air Preheater ◽  
Accurate Temperature ◽  
Ammonium Bisulfate ◽  
Lower Temperature ◽  
Novel Design

Nitrogen oxide (NOx) emitted from boilers in coal-fired power plant may be reduced by 90 percent through the application of the selective catalytic reduction (SCR). However, the escaped ammonia from the SCR systems could react with sulfur oxides (SOx) in the flue gas to form ammonium bisulfate (ABS) in exhaust systems. The blockage and corrosion caused by ABS seriously impact the rotary air preheater (RAPH), which would not only increase operating cost on ash-blowing and cleaning but also lead to unplanned outage. To solve the problem, in this paper a novel preheater system is proposed. A single preheater is split into two sub-preheaters, between which the main flue gas flow is mixed with the recirculated flue gas from outlet of the lower-temperature preheater. After the mixing point, a reaction chamber and a precipitator are installed. A numerical finite difference method (FDM) is employed to model the RAPH and obtain the accurate temperature distribution of fluid and heat transfer elements. The initial formation temperatures of (NH4)2SO4 and ABS are 200 °C and 170 °C, respectively, according to the flue gas composition in this work. By calculation, this split design of the RAPH is believed to be effective in reducing deposition of ABS.

scholarly journals Numerical Simulation on Double-nozzle Spray Evaporation of Desulfurization Wastewater

2021 ◽  
Author(s):  
Hong Xu ◽  
Shuqin Feng ◽  
Liehui Xiao ◽  
Yazhen Hao ◽  
Xiaoze Du
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Evaporation Rate ◽  
Flow Direction ◽  
Droplet Diameter ◽  
Numerical Results ◽  
Least Square ◽  
Lagrangian Model ◽  
Support Vector ◽  
Exhaust Heat

To achieve the near zero emission of wastewater in the flue gas desulfurization (FGD) system in coal-fired power plant and better utilize the exhaust heat from flue gas, a feasible technology of spraying FGD wastewater in the flue duct for evaporation is discussed in the present study. A full-scale influencing factor investigation on the wastewater droplet evaporation performance is established under the Eulerian-Lagrangian model numerically. The dominant factors, including the characters of wastewater droplets, flue gas and the spray nozzles were analyzed under different conditions, respectively. Considering the multiple factors and conditions in the process, a Least-Square support vector machine (LSSVM) model is introduced to predict the evaporation rate based on the numerical results. Conclusions are made that the flue gas temperature and droplet diameter are of great importance in the evaporation process. The spray direction of droplet parallel with the flue gas flow direction is profitable for the dispersion of droplet, resulting the maximal evaporation rate. A double-nozzle arrangement optimized with relatively small flow rate is recommended. The LSSVM model can accurately predict the evaporation rate using the numerical results with different conditions.

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