System and process for production of fuel gas from solid biomass fuel and for combustion of such fuel gas

A process for the production of fuel gas from solid biomass fuels and for the combustion of said fuel gas, said process comprising:

• (a) gasifying the solid biomass fuel in a gasification zone to produce a fuel gas, said solid biomass fuel being continuously exposed to a supply of gasification air in said gasification zone;
• (b) conveying the fuel gas from the gasification zone to a predetermined ignition point;
• (c) mixing the fuel gas with combustion air at the ignition point;
• (d) igniting the mixture of fuel gas and combustion air to produce a flame;
• and
• (e) shaping and directing the flame produced by injecting the combustion air from a plurality of tuyeres which are disposed to cause the combustion air to exit in a swirling pattern such that the swirling air pattern which exits from each tuyere overlaps the swirling air pattern from any adjacent tuyere.

A process for improving the radiant heat transfer process in a heat transfer device, which has a combustion zone and a heat transfer area adjacent to the combustion zone and which uses a solid biomass fuel, said process comprising:

• (a) gasifying a stationary bed of said solid biomass fuel in a gasification zone to produce a fuel gas, said solid biomass fuel being continuously exposed to a supply of gasification air in said gasification zone;
• (b) conveying the fuel gas from the gasification zone to a predetermined ignition point;
• (c) mixing the fuel gas with combustion air at the ignition point;
• (d) igniting the mixture of fuel gas and combustion air to produce a flame;
• and
• (e) shaping and directing the flame produced into the combustion zone toward the heat transfer area by injecting the combustion air from a plurality of tuyeres which are disposed to cause the combustion air to exit in a swirling pattern such that the swirling air pattern which exits from each tuyere overlaps the swirling air pattern from any adjacent tuyere.

A process for reducing the emissions of carbon monoxide, nitrogen oxides, sulfur oxides and particulates in a heat transfer device, which has a combustion zone and a heat transfer area adjacent to the combustion zone and which uses a solid biomass fuel, said process comprising:

• (a) gasifying the solid biomass fuel in a gasification zone to produce a hot fuel gas;
• (b) conveying the fuel gas from the gasification zone to a predetermined ignition point;
• (c) mixing the hot fuel gas with combustion air at the ignition point;
• (d) igniting the mixture of fuel gas and combustion air to produce a flame;
• (e) shaping and directing the flame produced into the combustion zone toward the heat transfer area by injecting the combustion air from a plurality of tuyeres which are disposed to cause the combustion air to exit in a swirling pattern such that the swirling air pattern which exits from each tuyere overlaps the swirling air pattern from any adjacent tuyere;
• and
• (f) supplying preheated ambient air to the gasification zone.

A process for retrofitting a heat transfer device, which has a combustion zone and a heat transfer area adjacent to the combustion zone and which uses a solid biomass fuel, said process comprising:

• (a) providing a gasification zone for producing fuel gas from solid biomass fuel, said gasification zone including a substantially horizontal air distribution grate for supporting a stationary bed of solid biomass fuel;
• (b) connecting a solid biomass fuel supply to the gasification zone;
• (c) connecting a gasification air supply to the gasification zone;
• (d) providing a pathway between the gasification zone and the combustion zone;
• (e) providing a predetermined ignition point in the pathway;
• (f) providing in the pathway a combustion air injection device comprising a plurality of tuyeres, for (1) mixing fuel gas and combustion air at the ignition point to initiate combustion of the fuel gas and the combustion air and, (2) shaping and directing the flame produced into the combustion zone toward the heat transfer area by arranging the tuyeres to cause the combustion air to exit the tuyeres in a swirling pattern such that the swirling air pattern which exits from each tuyere overlaps the swirling air pattern from any adjacent tuyere;
• and
• (g) connecting a combustion air supply to the combustion air injection device.