Study on the Kinetics and Removal Formula of Methanethiol by Ethanol Absorption
- To explore the relationship between the ethanol concentration and the MT removal rate according to the principle of physical absorption, and establish the mathematical formula for MT removal by ethanol absorption.
- To determine the kinetic parameters of the MT-ethanol absorption system.
2. Equipment and Methods
2.1. Deodorisation Test Device
2.2. Test Methods
- Absorption solution (20 L) was prepared with a preset volume ratio of ethanol/water in the absorption solution tank.
- The blower was operated. Mixed gas intake volume was controlled at 37 m3/h (intake load qG = 4700 m3/m2·h). MT was transmitted to the blower inlet port by controlling the reducing valve to form a preset concentration of MT odour.
- The spray pump was operated, and the absorption solution spraying volume was controlled at 40 L/h (spraying load qL = 5100 L/m2·h). The water–gas ratio was equal to 1.08.
- Concentrations of MT sampled from inlet and outlet pipes were measured under a sampling rate of 1.0 L/min after stable operation for 10–15 min.
- Waste absorption solution with a certain amount of MT absorbed in the system was discharged after each cycle.
2.3. Analysis Methods
- Z: packing layer height (m);
- GB: mixed gas flow rate (kmol/m2·h), GB = qG/Vm, where Vm is the molar volume of gas in the standard state (Vm = 22.4 L/mol);
- KY: overall mass transfer coefficient (kmol/m2·h);
- α: effective surface area of the unit packing volume (m2/m3);
- NOG: overall gas absorption number of mass transfer units, in which the difference of the vapour phase molar ratio is the driving force;
- S: desorption factor, S = mGB/LS, LS = xqLρ/M, where m is the phase equilibrium constant; LS is the absorbent (ethanol solution) flow rate (kmol/m2·h); x is the volume fraction of ethanol; ρ is the density of ethanol pure liquid (ρ = 0.789 kg/L); M is the molar mass of ethanol (M = 46 g/mol);
- X2: content of MT in the intake port of the ethanol (kmol MT/kmol ethanol).
2.4. Monitoring Methods
3. Results and Discussion
3.1. Experiment Results
3.2. Relationship between MT Removal Rate and Ethanol Volume Fraction
3.3. Calculation of Kinetic Parameters
3.4. Mathematical Formula Deduction
3.5. Mathematical Formula Verification
3.5.1. Verification Methods
3.5.2. Verification Results
- Engineering applications are needed to verify and revise the removal formula.
- Waste absorption solution can be supplied as a carbon source for the odour treatment process. For example, the two-stage biological treatment-ethanol absorption method can be used to remove the mixed odours, and ethanol in the second stage can act as a carbon source for first stage biological treatment.
- Waste absorption solution can be supplied as a carbon source for the sewage treatment process. Ethanol has been widely used as a supplement to biological denitrification , and the combination of ethanol absorption and biological denitrification will achieve maximum benefits.
- When the mixed gas flow was 37 m3/h (intake gas load qG = 4700 m3/m2·h), the flow of absorption solution spraying was 40 L/h (spraying load qL = 5100 L/m2·h) and the ratios of ethanol/water were 1:1, 1:5, 1:10, 1:20, and 1:30. MT removal rate increased with increasing rate of ethanol volume fraction in the absorption solution. The MT removal rate reached 80% when the ratio of ethanol/water was 1:5.
- In the deodorisation device of MT absorption by ethanol solution, the phase equilibrium constant m was 0.024, and the overall mass transfer coefficient KY was 2.55 kmol/m2·h for engineering.
Conflicts of Interest
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|Number||Equipment Name||Quantity||Type and Basic Parameters|
|1||Anti-corrosive type vortex pump||1||Type HG-1100 Air pressure 17.6 kPa |
Power 1100 w Blowing rate 180 m3/h
|2||Gas rotor flow meter||1||Type LZB-50|
|3||Gas rotor flow meter||1||Type LZB-3WB|
|4||Liquid rotor flow meter||1||Type LZB-6|
|5||Air sampler||1||Type QC-2A|
|6||MT gas tank||1||A mixed gas of MT and nitrogen (3%)|
|Volume Ratio||Cycle||Sampling Volume L||Average Inlet Concentration mg/m3||Average Outlet Concentration mg/m3||Removal Rate %|
|Ethanol : Water|
|Volume fraction (x)||3.23%||4.76%||9.09%||16.67%||50%|
|Cycle||Volume Ratio||Intake Volume m3/h||Spraying Volume L/h||Sampling Volume L||Average Inlet Concentration mg/m3||Average Outlet Concentration mg/m3||Removal Rate %|
|Cycle||Volume Fraction of Ethanol %||Intake Load m3/m2·h||Spraying Load L/m2·h||Experimental Removal Rate %||Theoretical Removal Rate %||Relative Error|
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Jiang, Y.; Lin, X.; Li, W.; Liu, X.; Wu, Y. Study on the Kinetics and Removal Formula of Methanethiol by Ethanol Absorption. Environments 2016, 3, 27. https://doi.org/10.3390/environments3040027
Jiang Y, Lin X, Li W, Liu X, Wu Y. Study on the Kinetics and Removal Formula of Methanethiol by Ethanol Absorption. Environments. 2016; 3(4):27. https://doi.org/10.3390/environments3040027Chicago/Turabian Style
Jiang, Yinghe, Xuejun Lin, Wenhan Li, Xiaoying Liu, and Yuqi Wu. 2016. "Study on the Kinetics and Removal Formula of Methanethiol by Ethanol Absorption" Environments 3, no. 4: 27. https://doi.org/10.3390/environments3040027