Lab-scale experimental tests of Power to Gas-Oxycombustion hybridization: system design and preliminary results
Power-to-Gas (PtG) represents one of the most promising energy storage technologies. PtG converts electricity surplus into synthetic natural gas by combining water electrolysis and CO2 methanation. This technology valorises captured CO2 to produce a ‘carbon neutral’ natural gas, while allowing temporal displacement of renewable energy. PtG-Oxycombustion hybridization is proposed to integrate mass and energy flows of the global system. Oxygen, comburent under oxy-fuel combustion, is commonly produced in an air separation unit. This unit can be replaced by an electrolyser which by-produces O2 reducing the electrical consumption and the energy penalty of the carbon separation process. The aim of this work is to present the design, construction and testing of a methanation reactor at laboratory scale to increase the knowledge of the key component of this system. Experimental data are used to validate the theoretical kinetic model at different operating temperatures implemented in Aspen Plus. CO2 conversions about 60-80% are found for catalyst temperature between 350 and 550 ºC. These values agree well with expected theoretical conversions from the kinetic model.