Spray drying absorption for desulphurization: a review of recent developments

Koech, Lawrence; Rutto, Hilary; Lerotholi, L.; Everson, Raymond C.; Neomagus, Hein W.J.P.; Branken, D.J.; Moganelwa, A.

doi:10.1007/s10098-021-02066-3

Cited by 22 publications

(11 citation statements)

References 52 publications

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“…According to Hill and Zank, a number of factors are considered rate-controlling within the spray drying system. In the liquid phase, the dissolution of the solid phase plays a vital role in controlling the rate, with the mass transfer rate being influenced by several factors such as solid properties (solubility, particle size, and shape) and liquid characteristics such as pH and composition . As the droplet starts to dry, it forms a solid crust composed of reaction products on its surface, and the diffusion through the reaction product layer becomes the new rate-controlling step …”

Section: Resultsmentioning

confidence: 99%

“…In the liquid phase, the dissolution of the solid phase plays a vital role in controlling the rate, with the mass transfer rate being influenced by several factors such as solid properties (solubility, particle size, and shape) and liquid characteristics such as pH and composition. 2 As the droplet starts to dry, it forms a solid crust composed of reaction products on its surface, and the diffusion through the reaction product layer becomes the new rate-controlling step. 39 In comparison with limestone and hydrated lime, trona has a high chemical affinity to water, making it readily soluble in water, forming Na + ions in solution.…”

Section: Sorbent Performance and Mechanismsmentioning

confidence: 99%

“…It has been a preferred choice for many utility plants due to its reliability, high SO 2 removal efficiency, and the availability of the sorbent (limestone, CaCO 3 ). On the other hand, interest in the spray drying FGD technology has increased over the past decade, for various reasons, e.g., (a) reduced installation and operating costs, (b) ease of retrofit to existing plants due to reduced footprint requirement, (c) ease of product handling with no requirement for sludge handling equipment and the associated maintenance, and (d) reduced water usage. − Despite the high reagent costs and low degree of utilization in spray drying scrubber process (typically 40–70%), it has been proven to have the ability to remove SO 2 from flue gas well below legislative limits. , …”

Section: Introductionmentioning

confidence: 99%

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Comparative Study of Sorbents for Spray Dry Scrubbing of SO₂ from Flue Gases

et al. 2023

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This study presents the findings of an investigation involving the absorption of SO2 from flue gases, using three different sorbents, in a spray dryer. Experimentation involved the evaluation of three sorbents, i.e., hydrated lime (Ca[OH]2), limestone (CaCO3), and trona (Na2CO3·NaHCO3·2H2O), and their relevant properties, for flue gas desulfurization by spray dry scrubbing. Experiments were conducted to explore the effects of spray characteristics in the spray drying scrubber on SO2 removal efficiency using the selected sorbents. The ranges of various operating parameters were considered, including the stoichiometric molar ratio of (1.0–2.5), the inlet gas phase temperature of (120–180 °C), and an inlet SO2 concentration of 1000 ppm. The use of trona gave better SO2 removal characteristics; a high SO2 removal efficiency of 94% was recorded at an inlet gas phase temperature of 120 °C and a stoichiometric molar ratio of 1.5. Under the same operating conditions, Ca[OH]2 and CaCO3 gave 82 and 76% SO2 removal efficiency, respectively. Analysis of the desulfurization products by X-ray fluorescence (XRF) and Fourier transform infrared (FTIR) spectroscopy revealed the presence of CaSO3/Na2SO3, a product of the semidry desulfurization reaction. A significant proportion of unreacted sorbent was observed when Ca[OH]2 and CaCO3 sorbents were used at a stoichiometric ratio of 2.0. Trona also gave the highest degree of conversion (96%) at a stoichiometric molar ratio of 1.0. Ca[OH]2 and CaCO3 gave 63 and 59%, respectively, under the same operating conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Sorbent Performance and Mechanismsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparative Study of Sorbents for Spray Dry Scrubbing of SO₂ from Flue Gases

et al. 2023

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“…The creation of a filter cake is essential for the de-dusting process, as it affects the retention period of the additive and, consequently, the contact time of additives and pollutants in the exhaust gas. The specific surface area of the solid (m 2 kg −1 reagent), the degree of gas mixing, the concentration of the gas to be adsorbed, the temperature and humidity of the flow, and the concentration of the reagent-typically described in terms of stoichiometric ratio-all have an impact on the efficiency of adsorption processes [13]. In order to achieve the same yields as wet systems, dry scrubbing systems must use significantly more reagents, necessitating at least a partial recirculation of the separated solids.…”

Section: Flue Gas Desulphurization (Fgd) With Seawatermentioning

confidence: 99%

Evaluation of Ca-Based Sorbents for Gaseous HCl Emissions Adsorption

et al. 2023

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The problem of acid gas exhaust emissions treatment has not been fully resolved at present. Dry adsorption of acid gases with alkaline sorbents is currently being investigated, to improve solid sorbents. In this study, 5 types of hydrated lime were characterised and tested. The sorption capacities were measured by means of a system consisting of a feed line (HCl/N2), a thermostatic reactor and a water absorber. The physical characteristics of sorbent samples were also compared. Analyses conducted with scanning electronic microscopy revealed that sample C1 showed uniform particle distribution. Samples C2 and C3 showed the co-presence of fine and coarse particles. Sample C4 showed very fine particles with agglomeration phenomena. In sample C5, fibrous elements were found. Energy dispersive spectrometry (EDS) analyses showed a similar composition of the samples, with the exception of the presence of Mg in some of them. After 30 min of testing, the following differences in sorption capacities with respect to C1 (3.59 mg g−1) were found: C2, −20%; C3, −13%; C4, −17%; C5, −3%. Higher sorption capacities were associated with more uniform particle size distributions. Conversely, agglomeration of fine particles may have adversely affected the performance of sorbents.

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“…Compared to WFGD, the SDA and DSI techniques have lower energy consumption and better fuel economy [4]. The desulfurization efficiency of the SDA technique has reached more than 90 %, there are no scaling and corrosion problems, and the water consumption is relatively low, requiring less space [5]. However, there are wear and blockage problems in the system.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Desulfurization Characteristics of Dry Sorbent Injection at Low SO₂ Concentrations

Liu,

Song,

Kang

et al. 2024

Chem Eng & Technol

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To effectively reduce SO2 emissions, flue gas desulfurization methods are widely used in coal‐fired power plants. In desulfurization, the dry sorbent injection (DSI) technology has the advantages of high desulfurization efficiency, simple operation, convenient adjustment, and low initial investment. Here, a pilot‐scale experimental system was designed and built to investigate the desulfurization characteristics of the DSI technology. The influence of the residence time of the desulfurizer, the reaction temperature, the stoichiometric ratio of the desulfurization reaction, the particle size of the desulfurizer, the inlet SO2 concentration, the dust concentration, and the water vapor content in the flue gas on the desulfurization efficiency at low SO2 concentrations was studied by injecting NaHCO3 into the pipeline. The desulfurization efficiency can be significantly improved by reducing the desulfurizer particle size or increasing the water vapor content in the flue gas at low SO2 concentration. An empirical formula describing the dependence of the desulfurization efficiency on experimental parameters is given.

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Spray drying absorption for desulphurization: a review of recent developments

Cited by 22 publications

References 52 publications

Comparative Study of Sorbents for Spray Dry Scrubbing of SO₂ from Flue Gases

Comparative Study of Sorbents for Spray Dry Scrubbing of SO₂ from Flue Gases

Evaluation of Ca-Based Sorbents for Gaseous HCl Emissions Adsorption

Experimental Study on Desulfurization Characteristics of Dry Sorbent Injection at Low SO₂ Concentrations

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Spray drying absorption for desulphurization: a review of recent developments

Cited by 22 publications

References 52 publications

Comparative Study of Sorbents for Spray Dry Scrubbing of SO2 from Flue Gases

Comparative Study of Sorbents for Spray Dry Scrubbing of SO2 from Flue Gases

Evaluation of Ca-Based Sorbents for Gaseous HCl Emissions Adsorption

Experimental Study on Desulfurization Characteristics of Dry Sorbent Injection at Low SO2 Concentrations

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Product

Resources

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Comparative Study of Sorbents for Spray Dry Scrubbing of SO₂ from Flue Gases

Comparative Study of Sorbents for Spray Dry Scrubbing of SO₂ from Flue Gases

Experimental Study on Desulfurization Characteristics of Dry Sorbent Injection at Low SO₂ Concentrations