Capturing CO2 Gas by Using Sodium Glycinate Solution and Regenerations of Solutions

• Main Authors: Lin, Sheng-Zhong, 林聖中
• Other Authors: Chen, Pao-Chi
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/37507902479072137536

碩士 === 龍華科技大學 === 化工與材料工程系碩士班  === 104 === This study used sodium glycinate as absorbent to absorb CO2 in the bubble column. The scrubbed solution was regenerated to explore the heat duty required. In order to understand the effect of process variables on the absorption process at a steady state condition, the sodium glycinate solution is controlled automatically by pH controller to keep the pH constant. The solution temperature in the column is controlled by cooling circulator. The simulated gas inlet conditions are at the CO2 concentration of 15% and the temperature of 50℃ respectively. The operating variables include pH(9.5-11), gas flow rate(3-9L/min), liquid temperature(25-40℃) and absorbent concentration(3-6M). For efficient experiment, the Taguchi method is used for experimental design. There are four parameters, each parameter has four levels. The number of experiments is reduced from 4^4=256 to 16. The absorption efficiency, absorption rate, overall mass transfer coefficient, gas-liquid molar flow rate ratio and absorption factor are obtained by material balance at a steady state condition. The optimum operating conditions and the order of parameter importance are obtained by S/N ratio analysis. The range of absorption efficiency is 25.64-86.84%, the range of absorption rate is 2.30×10^-4-8.56×10^-4mol/s·L, the range of overall mass transfer coefficient is 0.051-0.189s-1 and the range of gas-liquid molar flow rate ratio is 0.87-8.89, the range of absorption factor is 0.1298-0.4338mol/mol·L. The optimum operating conditions and the order of parameter importance are obtained by using S/N ratio to analyze the measured data, and the optimum operating conditions are verified. The result in verification shows the optimum values. The order of parameter importance shows pH>gas flow rate>absorbent concentration>liquid temperature. In addition, this study uses hot kerosene as heating medium to regenerate scrubbed solution from the solutions abtained in optimum conditions. There are 18 experiments, the operating temperature is 100-120℃. The heat of absorption, sensible heat and latent heat are estimated according to thermochemical data and experimental data. The obtained heat of absorption is 1.42-1.70GJ/t, the sensible heat is 1.76-4.65GJ/t, the latent heat is 0.53-7.43GJ/t. Generally speaking, the heat duty for regeneration process is 5.09-12.20GJ/t.