Laboratory of Chemical Energy Conversion Systems

Chemical energy conversion is a key process in integrating energies of different forms such as thermal and chemical energies, producing useful energy media/carriers such as hydrogen and carbonaceous solids and metal-based solids, simultaneously. In this laboratory, we are conducting researches on thermochemical conversion of carbonaceous resources such as biomass and coal, and on modeling & simulation of chemical process including complex chemical reactions with a detailed chemical kinetic approach toward developing chemical reaction processes with maximized energy utilization efficiency and minimized environmental impacts.

(1) Rapid reforming of biomass tar over mesoporous alumina and activated carbon.
Tar is one of the most problematic byproducts in biomass gasification processes due to its condensability. We found that tar-derived coke deposited over a type of mesoporous alumina reforms tar vapor nearly completely at 800°C within a period as short as 30 ms regardless the presence or absence of steam. It was also found that activated carbons are excellent tar reforming agents.

(2) “Pyro-coking” A rapid carbonization process of biomass by a combination of rapid pyrolysis and tar-coking.
We propose a process for rapid and biomass conversion into carbonized solid fuels, named Pyrocoking, which co-produces charcoal and tar-derived coke simultaneously while without tar. These solid fuels are highly reactive with steam, and therefore suitable for hydrogen production through steam gasification free from tar emission.


Fig.1 “Pyro-coking”. A rapid tar-free biomass conversion process.

(3) Reforming of tar (aromatics) produced in biomass gasification on the surface of charcoal.
We found that refractory aromatics such as phenol, naphthalene, and greater aromatics can be decomposed over charcoal almost completely at temperatures over 800°C, and the activity of charcoal is successfully maintained by making a kinetic balance between the coking and steam gasification.
(4) Study on the steam gasification of char from low-rank coals.
Experimental studies have been carried out on the steam gasification of chars obtained by rapid/slow pyrolysis from brown coals employing originally designed unique reactors. The catalytic effects of alkali and alkaline earth metallic species on the characteristics of steam gasification of char were investigated. On the basis of obtained results, a kinetic model following the catalytic and non-catalytic gasification of char was proposed.

(5) Detailed chemical kinetic modeling of pyrolysis of light hydrocarbons towards an better understanding of chemical vapor infiltration process for C/C composite production.
We are succeeded in developing an elementary reaction based gas phase reaction mechanism which can predict the concentration profiles of comprehensive gas phase species from hydrogen to coronene in the pyrolysis of light hydrocarbons at wide ranges of pressure and temperature.