Chain Grate Boiler

 

Introduction to Operating Principle

 

Chain grate boiler is a type of layered combustion coal-fired boiler, whose core is a slowly moving chain grate, which realizes continuous feeding, combustion, and slag discharge of coal
1.Fuel supply and coal distribution: Raw coal falls onto the chain grate at the front end through the coal hopper. As the chain grate slowly moves backwards like a conveyor belt, coal is evenly carried into the furnace.
2.Segmented combustion process: The air chamber below the grate is divided into multiple areas, and air is distributed according to different combustion stages

3.Heat transfer and slag discharge: The high-temperature flue gas generated by combustion flushes the heating surface of the boiler (furnace water-cooled wall, convection tube bundle, etc.), heating water into steam. The ash residue moved to the end is discharged into the slag removal machine at the rear, achieving continuous ash cleaning

(*For reference only)

1.The pressure parts of the boiler body, such as the drum, furnace liner, and pipes, are mainly made of boiler carbon steel, such as Q245R and Q345R.

Stove grate system (key components):

2.Stove plate: Made of heat-resistant cast iron (such as chromium cast iron) or heat-resistant steel to withstand high temperatures and wear.

3. Stove rack and chain: Made of high-quality carbon steel or alloy steel.

4. Furnace wall and insulation: The furnace section is constructed with heavy-duty furnace walls (refractory bricks) or lightweight blocks, and is covered with insulation materials (aluminum silicate fibers) and color steel plates on the outside.

5. Auxiliary system: Carbon steel, stainless steel or anti-corrosion materials are selected according to the characteristics of the medium for the air supply fan, induced draft fan, dust removal and desulfurization tower, etc.

SZL type assembled water tube boiler

1. Adopting a dual drum vertical arrangement, the combustion method is a chain grate. Burning biomass or pure coal to form solid fuels.

2. The water-cooled walls on both sides of the furnace adopt a membrane water-cooled wall structure; The water-cooled wall tubes on the front and rear walls of the furnace extend downwards to the upper part of the grate, forming front and rear arches, which increase the sealing performance of the boiler, increase the furnace volume and heating surface, and reinforce the strength of the rear arch.

3. Behind the furnace are the combustion chamber and convection tube bundle, with an economizer at the tail. The flue gas enters the tail flue through the furnace, combustion chamber, convection tube bundle, and economizer, and is discharged into the atmosphere through the dust collector, induced draft fan, and flue gas.

4. The front wall is equipped with secondary air controlled by valves, which is put into use when burning biomass fuel to enhance combustion and fully burn the fuel, thereby improving combustion efficiency. Higher feed inlet to meet the needs of biomass fuel.

(*For reference only)

• Process steam supply: provides heat source for the production process of the factory, such as steaming, drying, dyeing, and chemical reactions.
• District heating: By using heat exchange stations, the heat generated by boilers is converted into hot water to provide heating for the building complex.
• Power generation: In small thermal power plants or enterprise owned power stations, steam is produced to drive steam turbines for power generation (usually in cogeneration mode).