Student: Abdilwahab Eidi
Committee: Dr. Shuguang Deng & Dr. Bin Mu
Abstract:
The removal of CO2 from natural gas is called the sweetening process. The sweetening process is used to achieve the pipeline specification for CO2, which is <2% of volume in the natural gas. Absorption, membrane separation, and adsorption are three technology methods for CO2 separation from CH4 in natural gas. The absorption process solvent used is monoethanolamine (MEA) due to MEA being a cheap and stable compound. Increasing the MEA mass flow rate in the absorption process causes the process to have a more significant absorbent surface area. The optimal temperature for MEA absorption is between 30 oC and 40 oC. A sudden increase in the composition of MEA increases the CO2 fraction in the flow. The membrane process is done using hollow fiber membrane materials such as cellulose acetate (CA), polyimide (PI), and carbon membranes for CO2. The lower the diameter of the hollow fiber membrane, the higher the pressure drop in the process. The increased length of the hollow fiber slightly decreases the CH4 % loss and the CH4 purity. The packed density depends on the membrane dimensions, and the lower the packed density is, the higher the membrane process efficiency would be. The carbon membrane CO2/CH4 selectivity is higher than CA and PI membranes. Carbon membrane requires only a single stage to achieve high CO2 removal. In comparison, CA and PI membranes require multi-stages to achieve that high CO2 removal. The adsorption process uses zeolite r1KCHA as its adsorbent due to the high CO2/CH4 selectivity of 81. The lower the temperature and higher the pressure gets, the more CO2 adsorbed in the process. The absorption processes are more cost-efficient at medium to high model-size than adsorption and membrane processes. In comparison, adsorption and membrane are cost-efficient at low to medium-sized models with high pressurized natural gas.
Zoom Room: https://asu.zoom.us/j/8784437683
Presentation Time: 12:00-1:00 PM (Arizona Time)
