160t/h Cross-beam Type Grate
Product introduction
The cross-beam grate is a new type of cross-beam grate plate in which an inclined air outlet is applied to the cross-beam grate plate. This kind of grate plate differs from existing grate plates whose air outlet direction is vertically upward: the air outlet direction of the ventilation holes of the inclined-air-outlet cross-beam grate plate forms a certain angle with the vertical direction. When the grate ventilation leaves the grate plate it has a horizontal velocity, which is conducive to the horizontal diffusion of the ventilation in the coal layer, enhances the mixing effect of coal and air, and reduces the phenomenon of coal leaking from the grate.
Applicable scope 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 20~40t/h and above. Its main structural difference from the chain-belt grate is the use of many rigid cross beams. 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 (when the grate is very wide, several may be installed), and they are driven by the sprockets mounted on the front shaft (driving 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 shall not exceed 40mm, of which the content of 05mm coal fines shall 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 best.
(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 melting point temperature of the coal shall be greater than 1250℃.
(5) The caking tendency should not be too strong.
(6) The net calorific value of the coal shall 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 shall 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 seals; (5) air inlet pipes; (6) rear guide blocks; (7) front air baffle device; (8) shaft assembly; (9) coal hopper assembly.
(1) The support frame consists of left and right wall plates and front, middle and rear cross beams. Between the cross beams, the ash removal device and the air chamber partitions, several relatively closed large-capacity air chambers are formed; in this way the air intake of each zone on the grate surface can be adjusted, achieving full combustion of the fuel.
(2) The chain consists of chain links passing through rollers, intermediate guide blocks, chain shafts, retaining rings, pin shafts and the like. 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 driving 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 driving shaft and the guide device. The torque of the driving shaft is provided by the grate reducer through a coupling.
(4) The side seal is a horizontal right-angle flow-channel type side seal; in combination 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 chamber can be discharged.
(6) The layered coal feeding device is widely used in the coal hopper assembly; the coal entering the furnace is loosely layered and fully burned, improving the thermal efficiency of the boiler.
(7) The grate has a compact structure and a reasonable layout; the grate chain moves inside sealed guide rails, is not exposed to high temperature and only bears the moving tension of the grate; the grate made of heat-resistant material contacts the high-temperature burning coal layer 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, reducing the failure rate of the rear part of the grate during operation and improving operating efficiency.
(9) The grate chain runs in a tensioned state without arching or chain climbing; the chain movement is rolling friction, with low operating torque requirements and low noise.
(10) The grate has good overall sealing; it 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.
(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 shutting down the boiler.
Model parameters
| Boiler evaporation capacity | Grate effective area m² | Grate effective length mm | Grate effective width mm | Driving shaft torque N·m | Air supply mode | Ventilation section ratio % | Ventilation resistance pa |
|---|---|---|---|---|---|---|---|
| 20 t/h | 23.29 | 6830 | 3410 | 20000 | Two-side air supply | 8.5 | 1000 |
| 40 t/h | 35.38 | 7800 | 4550 | 30000 | Two-side air supply | 8.5 | 1000 |
| 65 t/h | 57.6 | 8150 | 6960 | 50000 | Two-side air supply | 8.5 | 1000 |
| 75 t/h | 63.7 | 7503 | 8490 | 70000 | Two-side air supply | 8.5 | 1000 |
| 80 t/h | 71.2 | 8360 | 8518 | 60000 | Two-side air supply | 8.5 | 1000 |
| 90 t/h | 80 | 9373 | 8540 | 70000 | Two-side air supply | 8.5 | 1000 |
| 100 t/h | 97.71 | 9165 | 9570 | 90000 | Two-side air supply | 8.5 | 1000 |
| 130 t/h | 126.66 | 9590 | 13210 | Dual reducers | Constant-pressure air chamber | 8.5 | 1000 |
| 160 t/h | 153.17 | 10458 | 14700 | Dual reducers | Constant-pressure air chamber | 8.5 | 1000 |
| 200 t/h | 185.94 | 10458 | 17780 | Dual reducers | Constant-pressure air chamber | 8.5 | 1000 |
| 260 t/h | 248.4 | 13500 | 18400 | Dual reducers | Constant-pressure air chamber | 8.5 | 1000 |
| 300 t/h | 295.2 | 14260 | 20700 | Dual reducers | Constant-pressure air chamber | 8.5 | 1000 |
Operating features
-
Good structural rigidity, the grate plates are not heated, nor are the cross beams and chains, making them safer and more durable;
-
Large effective grate area, low resistance and even air distribution;
-
The chain movement is rolling friction, with low operating torque requirements and low friction noise;
-
The grate has good overall sealing, preventing air leakage and air cross-flow between air chambers, and the air intake of each air chamber can be adjusted separately, which is convenient and practical;
-
The grate surface is flat, the grate blocks overlap each other and are closely arranged, so coal leakage and coal dropping are unlikely, and the grate plates can be replaced conveniently without shutting down the boiler;
-
The grate ventilation section area is large, generally up to 10%-17%, and combustion is extremely full;
-
The grate has no rear shaft and no eagle iron, so the rear part of the grate is unlikely to fail inside the furnace.