Gasification boiler for solid fuels, in particular for bales of straw, with optimised exhaust gas values

A gasification boiler for burning entire bales of straw at one time, the boiler comprising:

• a fuel and gasification chamber configured to receive an entire bale of straw at one time, the chamber closable by a filling door and having air feeds and depressions for collecting and holding ash resulting from the combustion of the bale of straw, the depressions disposed adjacent and parallel to a longitudinal grating arranged at the bottom of the fuel and gasification chamber and configured to allow coarse straw ash particles to completely combust and not enter a flow of a combustion gas;
• a combustion chamber situated below the grating and configured to receive and combust the combustion gas;
• a cylindrical secondary combustion chamber configured to further receive and combust the combustion gas connected at the bottom tangentially to an outlet of the combustion chamber so that the combustion gas rises therein in a swirling manner causing fine straw ash particles to accumulate at a bottom of the secondary combustion chamber;
• a cylindrical ash separator for collecting fine straw ash particles located downstream from the secondary combustion chamber and having an inlet connected at the top tangentially to an outlet of the secondary combustion chamber to force the fine ash particles against an outer wall of the ash separator, the ash separator having a substantially vertical pipe arranged centrally therein, the pipe having a lower opening approximately halfway up a height of the ash separator;
• a circular baffle plate fitted below the opening of the pipe in the ash separator such that a narrow annular opening exists between the outer wall of the ash separator and the baffle plate to allow for the deposition of the fine ash particles at the bottom of the ash separator after it is pressed against the outer wall of the ash separator;
• and
• a heat exchanger connected to an outlet of the ash separator.