Researchers at Chalmers University of Technology have developed a high-frequency radar technique that can measure how particles behave in fluidized beds with unrivalled precision
The radar transmitter and receiver can convert lower frequencies into extremely high frequencies of up to 340GHz. The signal is then transmitted through the horn antenna and uses a gold mirror, an off-axis parabola, to redirect the beam towards the fluidized bed, enabling very precise measurements with high resolution in space and time.
From the Chalmers University Website:
Fluidized bed combustion is one of the leading technologies used in the world’s thermal power plants. This technology converts solid fuels, such as biomass and waste, into district heating and electricity. Fluidization technology is also fundamental to many other processes that are expected to play an important role globally in the transition of energy systems, and in circular resource flows – such as in carbon capture, energy storage and the production of hydrogen and other fossil-free fuels.
Researchers at Chalmers University of Technology have now developed a radar technique able to provide a detailed characterisation of the flow of solids in fluidized beds, the lack of which has been holding back the development of these processes.
Fluidized beds is already the most effective technology for converting solid biofuels into energy. This technology results in an efficient and consistent rate of combustion because the solid particles assume a liquid-like state which helps to distribute the heat homogeneously in the combustion chamber. In brief, fluidization technology is based on a gas being blown through a bed of small sand-like particles in a reactor, so that these solid particles, the fuel and the gas become thoroughly mixed.
“The use of the high-frequency terahertz radar instrument demonstrated in our study has the potential to revolutionise how fluidized bed technology can be designed and used in many different industrial sectors – from energy conversion to the food industry and drug production. This is one of very few demonstrations of the use of pulse-Doppler radar technique at submillimetre wave frequencies, and it is the first time ever that it has been used for making measurements in a fluidized bed,” says Diana Carolina Guío Pérez, researcher in energy technology at Chalmers.
“We have been able to show that pulse-Doppler radar technique at frequencies up to 340 GHz can measure both the distribution of particles and their velocity inside a fluidized bed at a much higher resolution than other technologies can. This is information that has long been lacking in the field and will make it possible to improve and scale up process reactors and – in the case of energy conversion – reduce emissions of unwanted residual products,” says Marlene Bonmann, post-doc at the Terahertz and Millimetre Wave Laboratory at Chalmers University of Technology.