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Unformatted text preview: ABSTRACT: In this experiment the gas absorption rate and the overall mass transfer between carbon dioxide and the caustic soda solution were determined using gas and liquid analysis inside a packed column. During the running of the system several samples was collected every 10 min at the inlet and the outlet for both the gas and liquid. For the gas analysis the mole fraction was calculated first and it came out as 0.095 for the inlet which did not change during the experiment while at the out let it was 0.025, 0.035 and 0.045 at 10, 20 and 30 min respectively. Then the amount of CO 2 absorbed N was calculated which was equal to 0.0162, 0.00140, and 0.00118 gmol/sec respectively at the three different times. While the amounts of CO2 absorbed N using the liquid analysis were 0.00111, 0.001, and 0.00139 gmol/sec. . The percentages difference between the value of CO 2 , which was founded by using the gas analysis and that using liquid analysis, were 45.98 % at the first 10min, 40.33% at t=20 min and 14.98 % at t= 30min. the overall mass transfer coefficient Kog was determined which came out as follow for the gas analysis 0.01589, 0.012009, and 0.0908 gmol/m 2 .sec and for the liquid analysis 0.010885, 0.008557 and 0.01068 gmol/m 2 .sec. by comparison it gave the same percentage difference as the absorption rate. 1 OBJECTIVE: • To measure the absorption rate of carbon dioxide (CO 2 ) into caustic soda solution inside a packed column, using gas and liquid analysis. • To determine the overall mass transfer coefficient K og . INTRODUCTION: Absorption is the unit operation where one or more components of a gas stream are removed by being taken up (absorbed) in a nonvolatile liquid solvent. This operation is widely use in the industries for example sweetening a sour gas (i.e. remove CO 2 and H 2 S form the gas). Absorption can be either physical or chemical. In the physical absorption the gas is removed because it has greater solubility in the solvent than the other gases. However in the chemical absorption the gas to be removed reacts with the solvent and remains in the solution. The reaction can be either irreversible or reversible. For irreversible reaction the resulting liquid must be disposed whereas in the reversible reaction the solvent can be regenerated. Thus reversible reactions are often preferred. Chemical absorption usually has a much more favorable equilibrium relationship than physical absorption because solubility of most gases is usually very low. In order to provide a large gas-liquid contact area, absorbers are operated in packed and plate towers. There are three assumptions for absorption; the carrier gas is insoluble, the solvent is not volatile and the system is isothermal and isobaric....
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This note was uploaded on 12/28/2010 for the course CHEMICAL CHEM 409 taught by Professor Abdullahal-shammari during the Fall '08 term at King Fahd University of Petroleum & Minerals.
- Fall '08