DHL Type Boiler Introduction

In recent years,with the rapid deveplopment of marketing economy , people’s rising living standard,the environmental awareness is also growing. The state advocates to develop environmentally friendly energy-saving products.Our company introduced a single drum horizontal chain grate forced circulation hot water boiler. This type of boiler has been widely used in the country,and is ideal for central heating supply.

The boiler, a single drum horizontal P type forced circulation hot water boiler,adopt tiered coal feeder and trabeated style chain grate combustion equipment. Arrange the membrane wall tubes around and in the center of the furnace,to absorb the radiation heat of high temperature gas in the furnace.Slag screen shall be arranged at the outlet of the furnace,to further absorb heat radiation. In order to fully burn the coal and to ensure combustion efficiency,cover rate of front arch to the grate shall be 25%,the cover rate of rear arch to the grate shall be 57%, to achieve better effect. As the boiler is a little wider,arrange two steel tube type snake tube convection heating surface,after which set two air preheater. Flue gas in the pipe parallel scrub the tube bundle and air cross-flow scrub outside the pipe. The air preheater shall be allocated at the operation platform outside the steel support.The fornace has used the front arch and the rear arch to ensure the high boiler combustion efficiency and the grate heat loads of funace.The grate adopts stepless speed regulation,meeting any regulation of load and not affecting the thermal stability of combustion.

Boiler water flow

Feed warer →Rear water cooled wall of furnace→Two rows of snake tube heating surface→Two sides of water cooled wall of furnace→water wall panel→Front water cooled wall of furnace→Drum→Effluent.

DHL boiler characteristics:

1.Use mature Π-type arrangement, compact boiler layout, small size, less space requiremnet, reducing investment in the boiler room.

2.The arrangement of boiler heating surface has fully used boiler room.Around the furnace set the membrane wall,and connecting tubes arranged outside the boiler body. Convection heating surface uses snake tube structure.Inlet and outlet headers are set outside of the boiler, easy for installation and maintenance, less fouling, convienient for cleaning.

3.Drum arranged above the furnace, and connected headers with power failure protection pipe,thus could protect themselves better.

4.Useing forced circulation,The water velocity of boiler is a little high,the rising water speed between 1.0-1.15m / s and the decline water velocity between 1.1-2.0m / s. The use of drum, increase the boiler water capacity to protect the safe operation of the boiler.

5.Boiler adopts full shield structure,and the furnace using the whole membrane wall, sealing, and less air leakage,thus heat loss due to exhaust gas is much reduced, boiler thermal efficiency is improved,and at the same time reducing the boiler flue gas emissions and boiler fan power consumption

6.The boiler design a larger furnace, making the gas in the furnace to stay longer, and fully combusting the fly ash and combustible gases, improving combustion efficiency.Moreover,the rising speed of gas in the furnace is low, greatly reduced the carrying fly ash,and original concentration of boiler emissions.

7.This boiler arch adopts scientific and technological achievements of national "Plan" research project of Xi'an Jiaotong University (using rectangular furnace arch in the outlet of the rear arch), to ensure combustion of low-quality coal, and to improve boiler coal’s adaptability.

8.Boiler grate shall be trabeated style,to improve operation safety. Meanwhile grate-structured and well-tuned wind performance ensure complete combustion,and much reduced the mechanical loss of incomplete combustion.

9. Power failure protection

The upper part of the boiler set drum, increasing the volume of the boiler water,meeting the cooling needs of boiler water wall after power failure.

In avoid of the sudded waterhammer or even overheating of tubes while coming across power failure in operation,take the following measures:

There are steel pipes connecting with boiler drum in each circuit of water wall.Once power failure,the forced circulation shall be changed to natural circulation.

The tubes of water wall in the furnace are with a diameter of φ60mm and φ73mm.After a sudden power failure, a single tube can be formed of its own natural micro-circulation, so that the wall shall not be overheated in a certain period of time.

When power failure,according to the pressure of hot water,properly open some vent values.Meanwhile the pressure of hot water shall not be over 0.5 Mpa in boiler system.Under this pressure,the saturated temperature of hot water shall not be over 150°C,which allows only a small amount of boiler water become steam.As the drum is at the top of boiler, there are still water in other water pipes,which makes it’s safe in sudden power failure.

The terminal parameters shall be as per blueprint paper,and the model and parameters of forced draft fan and ID fan shall be as per the design of design institute.