How are the concentrations of various components in the desulfurization solution determined during the desulfurization of tannin? ?
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Generally, when the desulfurization effect is not satisfactory, the most common measure taken is to increase the circulation rate. However, increasing the circulation rate also brings about a series of problems: (1) An increased circulation rate leads to a shorter regeneration time, which may be unfavorable for regeneration and fail to achieve the desired results. (2) Increasing the circulation rate can result in higher power consumption! ! (3) The resistance of the desulfurization tower has increased! I’m wondering here whether increasing the concentration of the desulfurization solution within an appropriate range could also achieve the desulfurization effect ? Most importantly, I would like to ask everyone how the concentration of the alkaline solutions (Na2CO3, V, TEOS) is determined during the degassing process of tannin; is there any formula for calculation, or are there any standards that serve as a basis? ?
(1) Total alkali (expressed as Na2CO3): From the perspective of the H2S removal reaction, a higher total alkali content results in a larger mass transfer coefficient, which is beneficial for absorption; it also increases the sulfur capacity. However, an excessive amount of total alkali leads to more side reactions and the formation of precipitates that can cause tower blockages. Additionally, it increases the consumption of alkali, resulting in waste and higher operating costs. The total alkalinity is generally best kept between 0.5 and 0.7 N. (2) Alum (based on NaVO3): In the solution, NaVO3 is generally prepared by adding crude V2O5; the reaction equation is V2O5 + 2NaCO3 + H2O = 2NaVO3 + 2NaHCO3. When the concentration of NaVO3 in the solution is too high, the resistance in the desulfurization tower tends to fluctuate ； If the concentration is too low, the reaction speed will be slow and the degree of partial oxidation will be poor; it is advisable to keep the concentration of NaVO3 between 0.5 and 1.0 g/L. (3) Tannin concentration: If the tannin content is too low, the utilization efficiency of alum decreases, the sulfur capacity drops, and excessive by-product formation occurs ； Excess tannin content increases the viscosity of the solution, reduces the absorption and mass transfer coefficients, results in poor semi-removal efficiency, and also causes waste, thereby increasing operating costs. The tannin content is generally preferably kept between 1.5 and 3.0 g/L, with a gum-to-alum ratio of 1.5 to 2.0. In actual production, the various components in the desulfurization solution interact with each other; operating at the lower limit is more economical depending on the level of H2S entering the system.
Is there a template for calculating the mass transfer coefficient? Friends, please offer your support! ! Thank you! !
It is mainly to control the regeneration of the desulfurization solution