विषयसूची
Overhead cranes play a crucial role in waste-to-energy plants, including material handling, equipment installation, and maintenance. Proper configuration of these cranes not only enhances the operational efficiency of the plant but also ensures safety and stability in production. Based on years of engineering practice, this article explores the configuration and role of waste-to-energy plant overhead cranes, providing valuable insights for the design and operation of such facilities globally.
The scale of waste-to-energy plants varies significantly, ranging from small plants with a single line processing 300–500 tons per day (t/d) to large plants with 4–6 lines processing 750–850 t/d per line. Table 1 summarizes the crane configurations and setups in existing projects. The elevation data refers to the rail top elevation, with the effective grab bucket volume indicated in parentheses.
नहीं। | क्रेन | क्रेन प्रकार | Operating Mode | Installation Location | Lifting Capacity (Grab Bucket/m³) / t | कार्य कर्तव्य | टिप्पणी |
---|---|---|---|---|---|---|---|
1 | Garbage Grab Crane | Double Girder Grab Overhead Crane | Continuous, 24 hours/day (24 h/d) | Directly above the waste pit, elevation 25–35m | 11(6.3),12.5(8),18(10),20(12) | A8 | No fewer than two units, with one spare; explosion-proof features are not required |
2 | Ash Grab Crane | Double Girder Grab Overhead Crane | Continuous, 8~12 h/d | Directly above the slag pit, elevation 7–12m | 8(3.2),10(4) | A6~A8 | |
3 | Turbine Installation and Maintenance Crane | Double Girder Hook Overhead Crane | Intermittent | Inside the turbine room, elevation 13–15m | 20/5,25/5,32/5,50/10 | ए3 | |
4 | Comprehensive Pump Room Maintenance Crane | Electric Single Girder Underslung Crane | Intermittent | Inside the comprehensive pump room, elevation 6–9m | 2~3 | ए3 | |
5 | Fly Ash Temporary Storage Maintenance Crane | Electric Single Girder Underslung Crane | Intermittent | Maintenance of equipment inside the fly ash temporary storage room, elevation 6–9m | 2~3 | ए3 | |
6 | Workshop Maintenance Electric Hoist | Electric Single Girder Underslung Crane | Intermittent | At the top of the workshop, elevation 6–8 meters | 2~5 | ए3 | |
7 | Baghouse Dust Collector Electric Maintenance Hoist | Electric Single Girder Underslung Crane | Intermittent | Located at the top of the baghouse dust collector | 1~3 | ए3 | |
8 | Garbage Grab Crane Maintenance Electric Hoist | Electric Monorail Cranes | Intermittent | Directly above the garbage grab crane, elevation 32–40 meters | 3~5 | ए3 | |
9 | Induced Draft Fan Maintenance Electric Hoist | Electric Monorail Cranes | Intermittent | Directly above the induced draft fan, elevation 7–10 meters | 5~10 | ए3 | |
10 | Feed Water Pump Maintenance Electric Hoist | Electric Monorail Cranes | Intermittent | Directly above the feed water pump in the turbine room, elevation 6–8 meters | 3~5 | ए3 | |
11 | Primary Air Fan Maintenance Electric Hoist | Electric Monorail Cranes | Intermittent | Directly above the primary air fan in the incineration workshop, elevation 6–8 meters | 2~5 | ए3 | |
12 | Compressor Room Maintenance Electric Hoist | Electric Monorail Cranes | Intermittent | At the top of the compressor room, elevation 6–8 meters | 1~3 | ए3 | |
13 | Boiler Top Maintenance Electric Hoist | Electric Monorail Cranes | Intermittent | At the top of the boiler, above the elevation of the main boiler girder | 2~5 | ए3 | |
14 | Deacidification Tower Top Electric Maintenance Hoist | Electric Monorail Cranes | Intermittent | Above the elevation of the deacidification tower top | 1~3 | ए3 | |
15 | Leachate Pump Maintenance Electric Hoist | Electric Monorail Cranes | Intermittent | Above the leachate tank, elevation -2 to -5 meters | 1~3 | ए3 | Explosion-proof setup is required |
Table 1: Main Technical Parameters of Cranes in Waste-to-Energy Plants
(1)Waste Handling Crane
The function of the अपशिष्ट प्रबंधन क्रेन is to grab, pile, dump, and feed the waste inside the waste pit. It is installed above the waste pit, with the lowest point of the grab at least 2 meters clear of the waste feeding hopper level. The garbage grab crane control room is located either opposite or to the side of the waste hopper. The garbage crane and incinerator must operate simultaneously to ensure the safe and stable operation of the incineration plant; otherwise, it will disrupt the feed to the incinerator, potentially causing a shutdown of the entire plant. Therefore, the garbage disposal crane is a core piece of equipment in the incineration plant, requiring extremely high precision, stability, and reliability. Its duty class must meet A8 standards and should be configured with one active and one standby unit.
Additionally, considering the harsh environment (e.g., humid, acidic, containing harmful gases such as CH4 and H2S), it is critical to use mature and stable components for the grab, hydraulic systems, and electrical components. Based on years of operational experience, the concentration of flammable and explosive gases in the area where the waste handling crane operates is generally not high, and in most cases, explosion-proof settings are not required.
(2) Ash Grab Crane
The function of the ash grab crane is to move the slag discharged from the incinerator to the transport vehicles. Compared to the garbage grab crane, the performance requirements for the ash grab crane are relatively lower, as it does not need to operate in sync with the incinerator. Considering the limited volume of the slag pit, it is required that the maximum time to resolve any fault in the slag pit should not exceed one day. The control room for the ash grab crane is usually located on the side or at the end of the slag pit, and some incineration plants use remote control for operation.
The duty class of the ash grab crane is generally lower than that of the garbage grab crane, with A6 being sufficient. However, the actual configuration of the unit and the slag storage container should also be considered. In general, incineration plants with more than two incineration lines should use a duty class of A7 or A8. For large incineration plants with four incineration lines, considering the large width of the slag storage area, two ash grab cranes should be used.
The डबल गर्डर ओवरहेड क्रेन refers to the turbine installation and maintenance crane (hereafter referred to as the turbine crane). Its main function is the installation and maintenance of turbines and generators. Unlike the garbage grab crane and ash grab crane, the turbine crane is only used after the plant is operational. Due to the large size and mass of turbine-generator units, they are typically transported to the waste-to-energy plant in separate parts from the manufacturing facility. The turbine crane is then used to lift and install the components of the turbine and generator. After installation, the turbine crane must be used regularly for the maintenance and inspection of the turbine and generator. The crane is required to operate at full capacity at least twice per year (2 times/a).
The electric single girder underslung crane is primarily responsible for the maintenance and inspection of the comprehensive pump room, fly ash temporary storage room, workshop, and the baghouse dust collector itself. The design of these rooms requires the hoist to have lifting, trolley, and crane movement functions. For example, in the baghouse dust collector, components such as ash cleaners and bag cages need to be lifted and positioned across the entire work surface. The hoist must be able to reach all areas of the workspace, and the maintenance hoist should be used at least twice per year (2 times/a).
The track of the electric monorail crane is relatively simple, and it is mainly used for lifting and transporting fixed heavy equipment such as fans, pumps, and other rotating machinery. The maximum lifting capacity is no more than 10 tons, with most requiring movement along a single-direction track, while a few only need the lifting function. It is important to note that in some areas, there may be flammable and explosive gases such as H2S, CO, and NH3, requiring the use of explosion-proof motors.
In waste-to-energy plants, there are multiple sets of cranes, each varying significantly in type, lifting capacity, technical requirements, and layout. Items 1 to 3 in Table 1 generally represent the standard configurations for waste-to-energy plants, while other equipment is determined based on the plant’s scale, equipment configuration, and the owner’s requirements.
Cranes can be divided into operational equipment and maintenance equipment according to their function. Both the garbage grab crane and the ash grab crane fall under operational equipment, requiring daily operational hours. In particular, the garbage grab crane must operate continuously with precision and stability, and at least two sets of cranes are necessary. Most projects also require an additional standby grab crane to ensure that operations do not come to a halt due to a malfunction in the garbage grab crane. Maintenance cranes are used less frequently, and their environmental requirements vary.
(1) The maximum lifting capacity of the garbage grab crane is determined by the project’s unit configuration, processing capacity, and waste pit layout. Based on previous project designs, the lifting capacities and grab bucket volumes for garbage grab cranes and ash grab cranes are summarized in the table below.
Processing Scale | Garbage Crane / Ash Crane | |||
---|---|---|---|---|
Total Processing Capacity (t/d) | Number of Incineration Lines | Lifting Capacity (t) | Grab Bucket Volume (m³) | Number of Units |
≤600 | ≤2 | 11/8 | 6.3/3.2 | 2/1 |
600<total processing capacity<1200 | ≤3 | 12.5/8 | 8/3.2 | 2/1or2 |
1200<total processing capacity<1800 | 2≤incineration lines≤3 | 18/8 | 10/3.2 | 2/2 |
1800<total processing capacity<2400 | 2≤incineration lines≤4 | 18/10 | 10/4 | 3/2 |
2400<total processing capacity≤3000 | ≤4 | 18/10 | 10/4 | 4/2 |
2400<total processing capacity≤3000 | ≤4 | 20/10 | 12/4 | 3/2 |
(2) The lifting capacity of the turbine crane is related to the maximum weight of a single component during the unloading and installation of the generator. Based on accumulated experience, for waste-to-energy units with a capacity below 30 MW and fewer than 3 units, a single turbine crane is generally selected. When the number of units is equal to or exceeds 3, it may be advisable to choose two turbine cranes (one large and one small).
(3) The lifting capacity of other maintenance cranes (items 4–15 in Table 1) depends on the maximum weight of the equipment being serviced. The factors considered when determining the need for a hoist vary:
In general, the configuration of maintenance cranes in this range is similar to that of other industrial plants (such as wastewater treatment plants, thermal power plants, chemical plants, and steel mills). The main goal is to meet the maintenance needs of equipment, minimize maintenance time, and reduce labor intensity. When selecting small cranes for these applications, the characteristics of waste-to-energy plants do not significantly affect the choice of crane. Engineers can configure cranes according to relevant national or industry standards and site conditions.
Reference: Waste-to-energy Plant Cranes Configuration