Study of Carbon Dioxide Absorption from Hydrocarbon Stream Using Enhanced Amine Alovent (Stonvent)

Carbon dioxide (CO2) removal is an essential process in sweetening of natural gas. Natural gas generally contains a large quantity of methane (CH4) along with heavier hydrocarbons such as ethane, propone, isobutene, normal butane and considerable amount of CO2. CO2 must be removed from natural gas to protect pipelines and equipment since CO2 with the presence of water is highly corrosive. It also reduces the heating value of a natural gas stream and do not meet end users’ sales gas specification. Natural gas reserves with low CO2 content has gradually depleted and most of the remaining natural gas fields have high CO2 content mostly within 20 to 60 % and few are as high as 80%. Many efforts have been continuously conducted to improve the performance of absorption technology but the studies are mostly focused on CO2 concentration between 10 to 20% level only. As such, it is of our interest to study the absorption performance in elevated CO2 concentration using enhanced amine based solvent (Stonvent). In this preliminary work, the absorption performance of Stonvent was assessed and reported. The absorption experiment was conducted using Borosilicate glass column with diameter of 100mm and column height of 2.97m. The parametric study was conducted based on solvent flow rate. The solvent was also recycled in order to study the potential degradation of solvent performance to absorb CO2. Thermogravimetric analysis (TGA) conducted for the recycled solvent indicates that there were changes in decomposition profiles for the recycled solvent although it showed consistent absorption performance despite repeated usage at the tested experimental condition. Lower pH and refractive index for solvent was also observed after recycled usage of the solvent. As a conclusion, this preliminary investigation indicates that Stonvent has potential to remove CO2 at high concentration.