65t/h Cross-beam Type Grate

Product introduction

The cross-beam grate is a new type of cross-beam grate plate in which an oblique air outlet is applied to the cross-beam grate plate. This grate plate differs from existing grate plates, whose air outlet direction is vertically upward: the air outlet direction of the ventilation holes of the oblique-outlet cross-beam grate plate forms a certain angle with the vertical direction. When the grate air leaves the grate plate it has a horizontal velocity, which is conducive to the horizontal diffusion of the air in the coal bed, strengthens the mixing effect of coal and air, and reduces the phenomenon of coal leaking through the grate.

Scope of application and requirements

Scope of application

The cross-beam grate is a mechanized layer-combustion unit with a compact structure. The cross-beam grate is suitable for boilers with an evaporation capacity of 20~40 t/h and above. Its main structural difference from the chain grate is that many rigid cross-beams are used. The grate plates are installed in the corresponding grooves of the cross-beams, and the cross-beams are fixed on the drive chains. There are generally two drive chains (several may be installed when the grate is very wide), driven by the sprockets mounted on the front shaft (drive shaft).

It is widely used in various large boilers and in special equipment such as heating and drying equipment. It is suitable for burning bituminous coal, lignite and peat; specially designed incineration equipment can also burn other fuels such as bagasse and various types of waste.

Use requirements

The medium used in this grate must meet the following requirements:

(1) The maximum particle size of the coal must not exceed 40mm, of which the content of 05mm coal fines must not exceed 50%, and the content of 030mm coal fines shall be less than 25%.

(2) The moisture content of the coal is less than 20%, with 8~12% being the optimum.

(3) The ash content of the coal shall be less than 30% but shall not be lower than 10%, and the volatile matter content shall not be lower than 20%.

(4) The ash fusion temperature of the coal shall be higher than 1250℃.

(5) The coking tendency should not be too strong.

(6) The net calorific value of the coal shall be higher than 4350kcal/kg.

(7) If the above medium requirements conflict with the medium requirements of the coal feeding equipment, the higher requirement shall be taken.

The primary air temperature used in this grate must not exceed 200℃.

Structure and characteristics

The whole grate consists of the following components: (1) support frame; (2) grate chain; (3) ash removal device; (4) side seal; (5) air inlet pipe; (6) rear guide block; (7) front air baffle device; (8) shaft assembly; (9) coal hopper assembly.

(1) The support frame consists of left and right side walls and front, middle and rear cross-beams. Between the cross-beams, the ash removal device and the air compartment partitions, several relatively closed large-capacity air compartments are formed; in this way the air intake of each zone on the grate surface can be adjusted, so that the fuel burns fully.

(2) The chain consists of chain links passing through rollers, intermediate guide blocks, chain pins, retaining rings, pin shafts and so on. Bolt slots are cast on the chain links, and the cross-beams are fixed with bolts.

(3) One end of the grate is driven by the drive shaft and requires no driven shaft, and the other end is fitted with a guide device; the transition of the chain between the upper guide rail and the lower guide rail is accomplished by the drive shaft and the guide device. The drive shaft torque is provided by the grate reducer through a coupling.

(4) The side seal is a horizontal right-angle flow-channel type side seal which works together with the grate plate side seal; the two sealing lines improve the safety and reliability of operation.

(5) The ash removal device is of the push-pull type; by pushing and pulling the ash removal door handle to open the ash removal door, the fine ash and coal fines collected in the air compartment can be discharged.

(6) The layered coal feeding device is widely used in the coal hopper device; the coal entering the furnace is loosened and layered and burns fully, which improves the thermal efficiency of the boiler.

(7) The grate has a compact structure and a reasonable layout; the grate chain moves inside the sealed guide rails and is not exposed to high temperature, bearing only the tension of grate movement; the grate made of heat-resistant material contacts the high-temperature burning coal bed on the cross-beams and bears no stress while being heated, thus extending the service life of the grate.

(8) The grate has no rear shaft and no eagle iron, which reduces the failure rate of the rear part of the grate during operation and improves operating efficiency.

(9) The grate chain runs in a tensioned state, without arching up and without chain climbing; the chain movement is rolling friction, so the running torque requirement is low and the noise is low.

(10) The grate has good overall sealing; air leakage and cross-air between air compartments can be prevented. The air intake of each air compartment can be adjusted separately, which is convenient and practical.

(11) The grate surface is flat, and the grate plates overlap each other and are closely arranged, which can prevent coal leakage and coal dropping; the grate plates can be replaced conveniently without stopping the boiler.

Model parameters

Operating features

1. Good structural rigidity: the grate plates are not heated, and the cross-beams and chains are not heated either, so operation is safer and more durable;

2. The effective grate area is large, the resistance is low, and the air volume distribution is uniform;

3. The chain movement is rolling friction, the running torque requirement is low, and the friction noise is small;

4. The grate has good overall sealing and can prevent air leakage and cross-air between air compartments, and the air intake of each air compartment can be adjusted separately, which is convenient and practical;

5. The grate surface is flat, and the grate blocks overlap each other and are closely arranged, so coal leakage and coal dropping are not easy, and the grate plates can be replaced conveniently without stopping the boiler;

6. The ventilation cross-section of the grate is large, generally reaching 10%-17%, so combustion is extremely full;

7. The grate has no rear shaft and no eagle iron, so failures at the rear part of the grate inside the furnace are unlikely to occur.