Method and device for reducing hazardous emissions in internal combustion systems

A method for reducing pollutant emissions in a combustion system using a two-stage primary combustion process for a fuel including at least one of a solid fuel and a solid fuel mixture, the system including a primary furnace having a primary combustion chamber, a solid fuel burnout zone, a primary flue gas post-combustion chamber, and primary and secondary exhaust stream pathways, each connecting the primary combustion chamber with the primary flue gas post-combustion chamber, and including a separate secondary combustion train, the method comprising:

• burning the fuel in a primary combustion chamber while supplying primary gas in a substoichiometric amount so as to form a high heating-value combustion gas and a low-carbon solid residue;
• diverting a partial stream of the formed high heating-value combustion gas and passing a remainder of the formed high heating-value combustion gas to the primary flue gas post-combustion chamber via the primary exhaust stream pathway;
• passing the diverted second combustion gas stream to the secondary combustion train via the secondary exhaust stream pathway, the secondary combustion train including a combustion gas conditioner, a secondary combustion gas combustion chamber, and an energy recovery device, the passing being performed so as to:
• reduce, in the combustion gas conditioner, a temperature of the diverted partial stream in a temperature control device including at least one of a heat exchanger and a quench, and then
• clean, in the combustion gas conditioner, the diverted partial stream by removing at least one of ash, soot particles, and corrosive gas components in a downstream filter, and then
• burn the diverted partial stream in the secondary combustion gas combustion chamber while supplying oxygen-containing gas so as to produce hot, low-corrosive exhaust gases, and then
• recover, in the energy recovery device, energy from the hot, low-corrosive exhaust gases so as to produce burned-out energy-spent exhaust gas;
• recirculating the energy-spent exhaust gas to the primary furnace upstream of the primary flue gas post-combustion chamber via the secondary exhaust stream pathway and burning, in the primary flue gas post-combustion chamber, the energy-spent exhaust gas from the secondary exhaust stream pathway and the remainder of the high heating-value combustion gas stream from the primary exhaust stream pathway while adding an oxygen-containing secondary gas in superstoichiometric amounts so as to produce a primary exhaust gas;
• and
• feeding the primary exhaust gas to a primary steam generator and a primary flue gas cleaning unit.