Numerical simulation of NO₂ absorption using sodium sulfite in a spray tower

Abstract

BACKGROUND: Wet flue gas desulfurization combined with ozone is a promising technology which could remove NOx effectively. However, there are few reports focusing on simulations of the absorption process of NO 2 in a spray tower. A computational fluid dynamics model including chemical absorption was developed to simulate the absorption process of NO 2 . Simulations of different cases were executed to explore the influences of operating conditions. RESULTS: The errors between predicted and experimental values were less than 5% under different operating conditions and the model had depicted the tendency very well. For instance, an increase in L/G from 11 to 16 resulted in the growth of from 90.9% to 96.3%. When the solution concentration raised from 0.025 mol L −1 to 0.0875 mol L −1 could result in an increase of from 89.1% to 98.6%. CONCLUSION: The model developed in the present work was effective in determining the operating parameters of the spray tower for NO 2 absorption, which could be utilized for the design and optimization of industrial apparatus. Moreover, the model can also evaluate the best positions of the spraying nozzles, the distance between the spray levels and other parameters for industrial application.Supporting information may be found in the online version of this article.

Simultaneous Removal of NOx and SOx from Flue Gases Using ClO2: Process Scaling and Modeling Simulations

“…The interactions between nitrogen and sulfur are highly dependent on the pH level due to the dissociative reaction . At pH values ≥7, SO 3 2– is the dominant form, and reaction creates a potential route for NO 2 hydrolysis − Reaction has been studied experimentally, and it has a significantly higher reaction rate than reaction . This interaction between S­(IV) and NO 2 (aq) makes the simultaneous absorption of NO 2 and SO 2 an effective process under alkaline conditions.…”

The Chemical Behaviors of Nitrogen Dioxide Absorption in Sulfite Solution

“…Other S compositions besides SO3 2− and SO4 2− account for about 4% to 9% in the reaction system. Besides the above-mentioned nitrogen-sulfur compounds, Chen et al [32] and Zhuang et al [32,33] thought that the sulfite radicals could be formed by the reaction between NO2 and sulfite, the sulfite radicals could undergo either recombination or reaction with oxygen. By comparing Figure 4 with Figure 5, it can be seen that the amount of other S compositions is much lower than that of other Similarly, the calculated TS t is also more than the sum of detected SO 3 2− and SO 4 2− , as shown in Figure 5.…”

“…Other S compositions besides SO 3 2− and SO 4 2− account for about 4% to 9% in the reaction system. Besides the above-mentioned nitrogen-sulfur compounds, Chen et al [32] and Zhuang et al [32,33] thought that the sulfite radicals could be formed by the reaction between NO 2 and Appl. Sci.…”

Influence of Nitrogen Dioxide Absorption on the Sulfite Oxidation Rate in the Presence of Oxygen: Online Raman Measurements

“…In Figure a simplified schematic of the reaction paths possible when both SO 2 (g) and NO x (g) are present and in contact with an aqueous phase is shown. SO 2 absorption in water is equilibrium-controlled and leads to the formation of bisulfite and sulfite according to reactions and , respectively − Absorption of NO 2 in water takes place according to either reactions or , depending on the presence of NO and the pH level. − Nitrite, N­(III), is inherently unstable, especially under acidic conditions, and it can decompose into NO and NO 2 Several studies have shown that S­(IV) is efficient at hydrolyzing NO 2 (aq) at a high rate according to reaction . − The SO 3 2– may also be oxidized by O 2 following reaction . In experiments, it was found, as previously mentioned, that the oxidation of S­(IV) progresses at a much higher rate than what is explained by reactions and alone. Nash proposed that a radical-initiated chain of reactions was initiated by reaction and rather progressed through reaction where a sulfite radical was formed.…”