التحقيق العددي لتأثير نواتج الاحتراق لمحطة توليد كهرباء الناصرية البخارية على البيئة
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2022-12-08
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Predicting the release of pollutant concentrations into the atmosphere is essential in assessing potential environmental damage from industrial emissions. In order to solve the concentration equation for gases, it is necessary to determine as accurately as possible the velocity field and the intensity of turbulence at the atmospheric boundary layer in the region of interest. This thesis presents a numerical study to model the dispersion of pollutants from the stacks of the thermal power plant in Nassiriya, Iraq. The power plant operates on two types of fossil fuels (liquid and gas) and emits pollutants in the form of (CO, CO2, SO2, and NOX). A 3D mathematical model based on fluid mechanics equations is used with a modified standard k-ɛ turbulence model to calculate flow and scattering at the atmospheric microscale (for distances of several kilometers). In order to obtain the most realistic results with the mathematical model, it is necessary to consider essential phenomena related to scattering in the atmospheric boundary layer as well as the topography of the terrain.
In order to confirm the current study's validity, the created numerical model was compared with the previous experimental and theoretical models, and the comparison results showed good agreement, and the average error is about 3%. The calculation was performed for the column flow from the power plant chimney at variable factors such as plume velocity (mass flow rate), wind speed, wind direction angles, and different fuel types (liquid and gas).The ANSYS FLUENT CFD 2020 R2 program is used to simulate numerous flow and dispersion conditions.
The findings of this investigation demonstrated that the numerical model correctly predicts the column path and its concentrations. The results indicated that the concentration of pollutants in liquid fuels (crude oil) is higher than the concentration of pollutants in gaseous fuels (natural gas), where the maximum concentration of carbon dioxide (CO2) in crude oil and natural gas fuels at a
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wind speed of (2) m/s and a distance of 203 m is (0.00235, 0.0000362), respectively. It was found that the relationship between distance and concentration is an inverse relationship at different wind speeds, which means that concentration decreases with increasing distance due to the diffusion phenomenon. With increasing speed, the concentration decreases due to the diffusion speed and dilution rate. The maximum concentration of carbon dioxide at wind velocities of (2 and 10( m/s is (0.000594 and 0.000409(, respectively