40t/h Cross-beam Type Grate

Product introduction

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

Scope of application and requirements

Scope of application

The cross-beam grate is a mechanized layer-firing 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-belt grate is that many rigid cross beams are adopted. 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 by this grate must meet the following requirements:

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

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

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

(4) The ash melting point temperature of the coal should be greater than 1250℃.

(5) The caking property should not be too strong.

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

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

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

Structure and characteristics

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

(1) The support consists of left and right wall plates and front, middle and rear cross beams. Several relatively closed large-capacity air chambers are formed between the cross beams, the ash discharging device and the air chamber partition plates; in this way the air intake of each zone on the grate surface can be adjusted, and full combustion of the fuel is achieved.

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

(3) One end of the grate is driven by the drive shaft without the need for a driven shaft, and a guide device is installed at the other end; the transition of the chain between the upper guide rail and the lower guide rail is completed by the drive shaft and the guide device. The drive shaft torque is provided by the grate reducer through the coupling.

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

(5) The ash discharging device is of the push-pull type; by pushing and pulling the handle of the ash discharge door, the ash discharge door is opened and the fine ash and coal fines collected in the air chamber can be discharged.

(6) The stratified coal feeding device is widely used in the coal hopper device; the coal entering the furnace is loose and stratified 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 in sealed guide rails, is not exposed to high temperature and bears only the moving tension of the grate; the grate made of heat-resistant material contacts the high-temperature burning coal bed on the cross beams and bears no stress when 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 the operating efficiency.

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

(10) The grate as a whole has good sealing; air leakage and air cross-flow between air chambers can be prevented. The air intake of each air chamber can be adjusted separately, which is convenient and practical.

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

Model parameters

Operating features

1. The structure has good rigidity, the grate plates are not exposed to heat, and the cross beams and chains are not exposed to heat either, so the grate is safer and more durable;

2. The effective area of the grate is large, the resistance is small, and the air volume is distributed evenly;

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

4. The grate as a whole has good sealing and can prevent air leakage and air cross-flow between air chambers; the air intake of each air chamber can be adjusted separately, which is convenient and practical;

5. The grate surface is flat, the grate blocks overlap each other and are arranged closely, so coal leakage and coal dropping are unlikely, and the grate plates can be replaced conveniently without stopping the boiler;

6. The ventilation cross-sectional area of the grate is large, generally up to 10%-17%, and combustion is very complete;

7. The grate has no rear shaft and no eagle iron, so the rear part of the grate is not prone to failure in the furnace.