Browsing by Author "Niskanen, Marko"

Climate change, global warming and depleting fossil fuel reserves together with the globally increasing energy consumption have resulted in a need for new carbon neutral technologies to produce and store renewable energy. Microbiologial methanation of hydrogen and carbon dioxide is a promising carbon neutral technology to store renewable electricity as methane gas. Methane has the largest temporal and quantitative energy storage capacity of all the current energy storage pathways. There is also a globally increasing demand for carbon neutral transportation fuels and methane gas can be utilized in the existing natural gas infrastructure and combustion engines. The aim of this thesis was to study the methanation of hydrogen and carbon dioxide in a new type of a fixed bed reactor. A reactor in volume of 4 l was packed with support mixture consisting of vermiculite and perlite. Peak methane production rate of 0.15 l CH4 / h / 1 l reactor volume was achieved while the peak treatment power was 1.6 W / l. Hydrogen conversion rate during these achieved peak numbers was 25 %. Higher hydrogen conversion rate of 92 % was achieved in a stable operaton while the methane production rate was 0.03 l l CH4 / h / 1 l reactor volume and treatment power was 0.35 W/l. A simple and cost effective reactor structure for methanation of carbon dioxide and hydrogen is a promising way to store renewable energy and produce carbon neutral transportation fuels. Stable operation with high methane production rates and optimization of the reactor remains to be achieved. Present study was a part of a larger research project of the Natural Resources Institute Finland regarding the fixed bed reactor technology.