Continuing earlier work with tar reduction by partial oxidation of pyrolysis gas  thermal cracking has been evaluated as a gas cleaning process. The work has been focusing on cleaning gas from updraft gasifiers, and the long term purpose is to develop a tar cleaning unit based on thermal cracking. An experimental set-up has been built, in which a flow of contaminated gas can be heated up to 1290°C in a reactor made of pure Al2O3. Four measurements were made. Three with gas from a pyrolysis unit simulating updraft gasifier, and one with gas from an updraft gasifier. Cracking temperatures was 1200, 1250 and 1290°C, and the residence time at this temperature was 0.5 second. The measurements show that at the selected residence time of 0.5 second, the gas flow in a thermal tar cracking unit has to be heated to at least 1250°C to achieve sufficient tar cleaning. At 1290°C, a tar content as low as 15 mg/Nm3 was obtained on gas from an updraft gasifier. The lower heating value of the cleaned gas was 6.0 MJ/Nm3, and the energy content of the non condensable gasses was 19% higher than before cracking.
|Title of host publication||Proceedings of 1. World Conference and Exhibition on Biomass for Energy and Industry|
|Place of Publication||Seville, Spain|
|Publication status||Published - 2000|
|Event||1st World Conference and Exhibition on Biomass for Energy and Industry - Sevilla, Spain|
Duration: 5 Jun 2000 → 9 Jun 2000
|Conference||1st World Conference and Exhibition on Biomass for Energy and Industry|
|Period||05/06/2000 → 09/06/2000|