Investigation of characteristics of solid particles from a mixture of sewage sludge and wood pellets synthetic gas and their clean-up

Abstract

The most reasonable way to utilise sewage sludge in Europe is in energy production. In the process of thermochemical conversion of sewage sludge, combustible gas is produced. Studies of synthetic gas composition show that this gas contains various impurities, which must be cleaned before gas supply to the final user. Although there are many ways to clean toxic materials existing in the synthetic gas, the application of plasma treatment seems the most promising. Exposure to the high temperature of plasma changes the structure and the chemical composition of solid particulates existing in the gas. In this study on the synthetic gas, ESP cleaning efficiency, size and elemental analysis of solid particles collected from different parts of the experimental setup with a gasifier operating on a mixture of sludge and wood pellets were analysed. The results showed the difference in particle sizes and changes in elemental composition of particles collected from different parts of the experimental setup. It was determined that the synthetic gas obtained by gasification of a mixture of sludge and wood pellets contains a great concentration of solid particles, which leads to the total collection efficiency of an electrostatic precipitator being only about 60 %.