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Operating experience with chemical looping combustion in a 120kW dual circulating fluidized bed (DCFB) unit

2009; Elsevier BV; Volume: 4; Issue: 2 Linguagem: Inglês

10.1016/j.ijggc.2009.09.014

1750-5836

Philipp Kolbitsch, Johannes Bolhàr‐Nordenkampf, Tobias Pröll, Hermann Hofbauer,

Oil, Gas, and Environmental Issues

This study presents first operating experience with a 120 kW chemical looping pilot rig. The dual circulating fluidized bed reactor system and its auxiliary units are discussed. Two different oxygen carriers, i.e. ilmenite, which is a natural iron titanium ore, and a designed Ni-based particle, are tested in the CLC unit. The pilot rig is fueled with H2, CO and CH4 respectively at a fuel power of 65–145 kW. High solids circulation, very low solids residence time and low solids inventory are observed during operation. Owing to the scalability of the design concept, these characteristics should be quite similar to those of commercial CLC power plants. Ilmenite shows a high potential for the combustion of H2-rich gases (e.g. from coal gasification with steam). The H2 conversion is quite high but there is still a high potential for further improvement. The Ni-based oxygen carrier achieves the thermodynamic maximum H2 and CO conversion and also very high CH4 conversion. A variation of the air/fuel ratio and the reaction temperature indicates that the Ni/NiO ratio of the particle has an influence on the performance of the chemical looping combustor. Generally, low solids conversion in air and fuel reactors is observed in almost any conditions. Despite a very low H2O/CH4 molar ratio, no carbon formation is observed.