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Schematic of the desulphurization process coupled with the droplet drying process. Adapted from Hill and Zank (2000)
Source publication
In semi-dry flue gas desulphurization in a spray dry scrubber, the desulphurization efficiency is a result of the competition between the spray droplets SO2 absorption rate and the droplets drying rate. The complexity of the process is increased by the 3D nature of the hydrodynamics occurring within the dryer. For accurate optimization of the desul...
Citations
... Therefore, it is imperative to control SO 2 emissions and reduce air pollution. The semi-dry flue gas desulfurization process is widely used in production due to low investment and simple equipment operation and maintenance [6][7][8]. The spouted bed has significant advantages in the desulfurization effect [9][10][11]. ...
... Sulphur in coal combines with air during combustion to create sulphur dioxide (SO2). Sulphur dioxide is one of the many contaminants in our atmosphere (SO2) [2]. Burning things containing sulfur releases a harmful gas into the atmosphere. ...
... Researchers have looked into flue gas desulphurization using absorbent synthesis from a combination of calcium hydroxide, calcium oxide, and calcium sulphate to address these difficulties [9]. Numerous studies have shown that, for instance, when coupled with Ca (OH)2 or CaO during the hydration process, coal ash can create an absorbent with a higher SO2 capture capacity than hydrate lime [2,8,10]. ...
The main reaction parameters examined were the amount of blast furnace slag, the hydration duration, ammonium acetate concentration, and temperature. The Response surface methodology was employed to quantify their impact on the sorbent's surface area. Using a central composite design, the surface area of the resulting sorbent corresponding to Brunauer-Emmett-Teller (BET) was investigated. The sorbents produced range in surface area from 49.89 to 155.33 m2/g. Additionally, the effectiveness and response prediction capacities of the Response Surface Methodology (RSM) and Artificial Neural Network (ANN) modeling methodologies were investigated. The models were assessed using various statistical metrics, including (MSE) mean squared error, (ARE) average relative errors, the (SSE) sum of squared errors, (HYBRID) Hybrid fractional error function, (SAE) Sum of the absolute errors, (R2)coefficient of determination, and Root means square. According to statistical evidence, the ANN approach surpassed the RSM-CCD model approach. The surface area of the sorbent was shown to be significantly influenced by interactions between variables in addition to all the individual variables examined. The sorbent was made from a material with substantial structural porosity based on SEM. The functional groups were identified using FTIR. The XRF determined the elemental composition of BFS-based sorbents.
... The capability of numerical modeling of process plants has been strongly influenced throughout history by the development of multiphase flow modeling and available hardware. For a thorough description of all chemical and physical phenomena inside the FGD absorber and the absorber sump, especially with regard to the modeling of SO 2 absorption, O 2 absorption, droplet drying, etc., advanced CFD approaches must be used [18][19][20]. ...
A numerical model of a flue gas scrubber sump is developed with the aim of enabling optimization of the design of the sump in order to reduce energy consumption. In this model, the multiphase flow of the continuous phase, i.e., water, and the dispersed phase, i.e., air bubbles, is considered. The air that is blown in front of the agitators, as well as the influence of the flow field of the agitators on the distribution of the dispersed phase and the recirculation pumps as outlet, is modeled. The bubble Sauter mean diameter is modeled using the population balance model. The model is used to analyze operating parameters such as the bubble retention time, the average air volume fraction, bubble Sauter mean diameter, the local distribution of the bubble size and the amount of air escaping from the pump outlets at two operating points. The purpose of the model is to simulate the two-phase flow in the sump of the flue gas scrubber using air dispersion technology with a combination of spargers and agitators, which, when optimized, reduces energy consumption by 33%. The results show that the homogeneity of air is lower in the bottom part of the absorber sump and that the amount of air escaping through recirculation pipes equals 1.2% of the total air blown into the absorber sump. The escaping air consists mainly of bubbles smaller than 6 mm. Additional operating point results show that halving the magnitude of the linear momentum source lowers the air retention, as well as the average homogeneity of the dispersed air.
... (2019) used a 3D CFD method to more accurately evaluate tidal current energy potential, Elfeky et al. (2022) successfully increased thermal behavior efficiency of a thermal energy storage thermocline tank by using a CFD approach to calculate the optimal heat transfer fluid inlet velocity, Lerotholi et al. (2022) investigated available CFD models for semi-dry flue gas desulphurization in spray towers for the process hydrodynamics, drying and absorption. Regarding the CLC process, Parker (2014) developed a CFD model that takes into account ilmenite as the OC and coal as the fuel, in a CFB setup, to calculate fluidization regimes, circulation rate, reactor efficiencies, and temperature profiles. ...
Chemical looping combustion (CLC) offers innovative carbon capture via oxygen carrier (OC) circulation between separate reactors. Circulating fluidized beds facilitate OC transport between fuel and air reactors for reduction and oxidation. By avoiding direct contact between fuel and air, minimal energy is required for CO2 separation. Disadvantages resulting from the conventional circulating fluidized bed system are the additional energy necessary for OC transportation and the challenge to operate at elevated pressure. A novel approach to CLC is proposed by considering a packed bed system with stationary OC particles undergoing periodic reduction and oxidation stages by shifting feed gas streams. The major design benefit lies in the prospect of process operation at high pressure. Finding optimal operating conditions is a mandatory step prior to implementing the process at industrial level. In this work, COMSOL Multiphysics was used for computational fluid dynamics (CFD) modelling in order to simulate the syngas-based CLC process with ilmenite OC in a packed bed reactor configuration. Mass, momentum and heat transfer mechanisms were accounted for to describe the combustion, purge and regeneration stages within a bed of randomly packed spherical OC particles at both macro- and micro-scale dimensions. The scope of the particle-resolved CFD multiscale model with realistic bed morphology was the in-depth analysis of the intraparticle phenomena occurring during the redox reactions, with emphasis on heat transport. Model results agree with published literature and provide additional understanding regarding the process in order to contribute towards the design of a flexible and energy efficient power plant concept.
Graphical abstract
Modelling syngas-based CLC steps considering a realistic packed bed morphology for ilmenite OC conversion
