J.A. Medrano

Advancement of an Infra-Red Technique for Whole-Field Concentration Measurements in Fluidized Beds

For a better understanding and description of the mass transport phenomena in dense multiphase gas-solids systems such as fluidized bed reactors, detailed and quantitative experimental data on the concentration profiles is required, which demands advanced non-invasive concentration monitoring techniques with a high spatial and temporal resolution. A novel technique based on the selective detection of a gas component in a gas mixture using infra-red properties has been further developed. The first stage development was carried out using a very small sapphire reactor and CO2 as tracer gas. Although the measuring principle was demonstrated, the real application was hindered by the small reactor dimensions related to the high costs and difficult handling of large sapphire plates. In this study, a new system has been developed, that allows working at much larger scales and yet with higher resolution. In the new system, propane is used as tracer gas and quartz as reactor material. In this study, a thorough optimization and calibration of the technique is presented which is subsequently applied for whole-field measurements with high temporal resolution. The developed technique allows the use of a relatively inexpensive configuration for the measurement of detailed concentration fields and can be applied to a large variety of important chemical engineering topics.

CHAPTER 2:Chemical Looping for Hydrogen Production and Purification

Chemical Looping is an interesting technology that allows (partial) oxidation of a fuel without direct contact between the fuel and air. Instead, a solid material, referred to as oxygen carrier, is used to transport the oxygen from the air to the fuel by solid circulation between two reactors operated under different conditions. As such, the products of the fuel oxidation are nitrogen free. In the case of combustion (full oxidation), this means that the CO2 is not diluted with nitrogen. In the case of reforming/partial oxidation, the syngas is nitrogen free and thus easier to purify. In the presence of an H2 permselective membrane, the syngas production (through chemical looping) and pure H2 separation are combined in the same unit. This chapter introduces the chemical looping principle and describes a new reactor concept that combines the advantages of chemical looping technology and membrane reactors. This concept is referred to as Membrane-Assisted Chemical Looping Reforming (MA-CLR), which allows high hydrogen purity with integrated CO2 capture and high energy efficiency.