The influence of the temperature on the process has been studied through the comparison of the different trials, with respect to the yields, to the chemical composition and to the mass balances of the main components of the process. In this respect, it is important to remark that a large amount of soot was produced during the tests, which was appreciably reduced only at high temperature (1000 C); consequently, to prevent the plugging of the pipes, a severe filtration with ceramic wool was necessary, which rendered extremely difficult the separation between tar and soot. For this reason, both fractions were collected together and coded as ‘‘oil’’. The application of an in bed or ex bed catalytic upgrading could improve
the process. This issue has been already discussed in a pr