Pulverized Fuel Boiler is another name of Pulverized Coal Boiler or Coal Powder Boiler. Pulverized coal boiler island mainly includes pulverized coal storage tower, fuel feeder, burner, boiler body, flue gas pollutant removal device, ash silo, ignition oil (gas) station, compressed air station, inert gas protection station, and measurement & control system. The burner reserves a natural gas interface to enable backup or interchange of pulverized coal and natural gas.

  1. Pulverized Coal Storage Tower

Pulverized coal storage tower is a key device of the system. The tower consists of three parts: ellipsoidal head on the top, cylindrical shell in the middle, and cone bucket in the bottom. The top has several interfaces for installing bag filter, gravity explosion-proof door, various sensors and other auxiliary facilities. The middle wall has many openings for installing temperature sensor. The bottom wall also has openings for installing temperature and material level sensor.

  1. Feeder

Feeder is the most important equipment in pulverized fuel boiler system. It is responsible for continuous and stable feeding to the burner. In fact, the furnace safety and operating quality rely on the feeder. Active feeder mainly refers to “star bird” coupled Venturi.

  1. Pulverized Coal Burner

Pulverized coal burner is the core of the flue gas system. The complete burner consists of secondary air silo, secondary air guide ring, ignition silo, log spiral guide vane distribution plate, double-cone combustion chamber, and pulverized coal spray pipe.

Development of Pulverized Fuel Boiler in China

  1. Pulverized Fuel Boiler Body

Pulverized coal boiler mainly has three structural types.

1) Pulverized Coal Boiler with a capacity of 4~25t/h adopts WNS fire tube shell type, membrane wall reversal chamber. It features compact structure, high strength, good air tightness, packaged delivery and simple maintenance.

2) Coal Powder Boiler with a capacity of around 30t/h adopts DZS membrane wall convection heat surface. High-speed fire tube improves convective heat transfer effect, and avoids low-load ash accumulation.

3) Pulverized Coal Fired Boiler with a capacity of 40-160t/h adopts DHS membrane wall convection heat surface vertical structure. Burner is at the top and spraying downwards. Low temperature superheater is in a horizontal flue duct.

  1. Dust Removal and Desulfurization

The complete system integrates buffer, reactor, cyclone separator, bag filter, circulating ash silo, feeder, humidifying mixer and distributor.

  1. Low-nitrogen Combustion and Denitration

Low-NOx emission solution is air staging combustion and selective non-catalytic reduction or selective catalytic reduction (namely SNCR or SCR). SNCR and SCR feature complex system, large investment and expensive operation. Therefore, we are studying deep air staging coupled with flue gas recirculation combustion system.

  1. Measurement and Control

Measurement and control is basically completed by a PLC (or DCS) and a host computer. Complete system consists of various sensors, data cables, power cables, actuators, logic operation modules, engineering configuration software, power distribution cabinets, control cabinets and switch cabinets. The measurement and control mainly focus on steam-water unit, combustion unit, combustion air unit, induced air unit and auxiliary equipment.