Hyperbranched Polymers in Absorption: Experimental Co2 Solubilities

Oxidative coupling of methane (OCM) is an approach for the direct catalytic conversion of methane to higher hydrocarbons, which is currently being investigated at the Berlin Institute of Technology within the cluster of excellence UniCat (Unifying Concepts of Catalysis). Hereby, the conversion to ethylene is the major goal of the process. In the downstreaming process subsequent to the OCM reaction, a purification step takes place, where carbon dioxide has to be removed from the raw gas. This is done by chemical absorption using an aqueous amine solution, which can have several disadvantages such as a high energy demand for regeneration or solvent losses. However, it has been shown that hyperbranched polymers are promising candidates for gas absorbents with a high capacity for CO2 and with large selectivities. In this work, a commercially available hyperbranched polymer (Boltorn Perstorp) is investigated. The potential for its use as absorbent in the separation of CO2 is evaluated by measuring solubilities. The results obtained are reported in terms of Henry constants within the temperature range of 283.15 to 303.15 K. In addition, the densities of the pure polymer or its solution with ethanol are measured in the same temperature range.