Chemical looping combustion is a new technology which is expected to be a short term solution to the clean energy crisis by allowing for a cost effective and relatively simple means of capturing and storing CO2. This report has been provided to overview the experimental research undertaken into a new method of manufacturing metal oxides and to draw conclusions on the use of different metal oxides as oxygen carriers in chemical looping combustion.
This investigation is critically important due to the pivotal role that the metal oxide oxygen carrier plays in the feasibility of utilising chemical looping combustion for CO2 capture and sequestration. According to current literature, a number of problems are still present in the metal oxides. This research aims to address four of the main problems, namely limitations in reactivity rate, oxygen carrying capacity, sample degradation and carbon deposition.
Experimentation was undertaken on the use of five metal oxides; copper, iron, nickel, cobalt and manganese. The results obtained showed that carbon deposition was a major issue and limited the analysis of the nickel, iron and cobalt results. Manganese was found to have good conversion rates however its oxygen carrying capacity was relatively low compared to that of the copper based sample.
As such, a detailed experimental investigation was undertaken on the copper-based oxygen carriers by changing parameters and noting the influence on the samples performance. The optimisation included; increasing the operational temperature, increasing and decreasing the active metal oxide concentration and testing the sample over an extended number of cycles.
This experimentation identified that the most promising oxygen carrier was one based on copper oxide. It was found that the sample prepared with 75% active copper oxide and 25% magnesium oxide support offered the most favourable multicycle performance characteristics and is therefore a good candidate for use in chemical looping combustion. In analysing the performance of this metal oxide it was possible to conclude that the new manufacturing method, wet-mixing, is an effective method for producing metal oxides and that further analysis and investigation of this method be performed.