Low-emission straight-flow and swirl pulverized-coal burner devices

Low-emission gas and fuel oil burners

The All-Union Thermal Engineering Institute (VTI) developed low-emission gas-water split gas and fuel oil burner with furnace gas recirculating to the secondary air duct to improve combustion of gas and fuel oil in boiler plants, with next implementation of this burner at a facility of ZIO-Podolsk company. Recirculating gases are forwarded from the smoke sucker to the blown fan. There are two ducts in the burner, i.e. the peripheral duct and the central duct. Axial vane swirlers are installed in the ducts, and their blades are 40-45º inclined, and correspondingly directed to the burner’s axle.

Around 60-65% of the air – recycled gas mixture is forwarded to the peripheral duct, and 40-35% are forwarded to the central duct. Air flow in operating burner’s ducts is adjusted with the help of specific valves, which enable to smoothly adjust it up to complete deactivation of any burner’s duct. The gas flow is also adjusted within the boundaries of the given range of loads.

The burner is equipped with the ignition control devices (ICD) for two types of fuel; their constructions are simple, and the flame ignition is stable. They are operated from the automatic control board. Construction of the burner allows burning the fuel oil independently, and for this purpose, special igniter is installed in the central duct. This igniter is directed to the burner when gas is combusted.

The burner lets the boiler plant operate at full capacity at combustion of natural gas and fuel oil, and also at combustion of their mixture with the least excess air factor equal to 1.03-1.05. Ecological (green) indices of the boiler plant are in many ways dependent on the burner’s construction. Around 15-20% of recirculating gases, which are forwarded to the burner, may considerably improve its operational characteristics, reducing total amount of air pollutants.

Designing the boiler plant, it is necessary to provide it with 15-20% gases for recirculation. Operation of the boiler plant with 15-20% recirculating gases provides the level of NOx emission less than 96 mg/nm³ at combustion of natural gas, and less than 150 mg/nm³ at combustion of fuel oil. Tests performed at the Shaturskaya power station showed good ecological (green) indices: the level of NOx emission was not more than 80 mg/nm³ at combustion of gas.

Swirl adjustable burner for furnaces equipped with mills

Construction of the burner allows adjusting the jets’ range and the aperture angle, and changing location of the flame body in furnace chamber. Similar burners are installed in boiler plants BKZ-160, BKZ-220, PK-38 for combusting the Kansko-Achinsk and Gusinozersk coals.

Swirl burner with adjustable swirl of secondary air.

The burner is designed for combustion of the anthracite culm and the black coal in furnaces with liquid and solid slag removal. It allows providing detailed adjustment of the fuel igniting conditions and the flame aperture angle. Similar burner is installed in boiler plants with the steam capacity equal to 75/420 t/h.

Swirl pulverized-coal burner equipped with the HDC system.

Influenced by an air stream coming out from the mixer nozzle, dust is blown and forwarded through the dust flue to the burner. At the outlet of the burner, aero mix flows into the combustion compartment, mixing with air and hot flue gases. Dust distributor in the shape of cone splitter is installed at the outlet of HDC’s dust flue to the burner’s outlet.

Straight-flow and fantail burners for the tangentially fired furnaces.

Construction of this burner is distinguished for its secondary air duct, which is divided into the lateral part and the inner part. This allows giving some air apart from the major flow of air-fuel mixture. At the same time, much less concentration of oxygen is provided at a place of ignition and combustion of coal-volatile matters, which results in reducing the level of NOx. Burners can be equipped with either a conventional fuel supply system, or a system of transportation of coal of high concentration of HDC. Those burners are applied to projects of reconstruction of boiler plants BKZ-160 and P57R for combusting the Ekibastuz coals.