Industrial Overhead Cranes in Biomass Power Generation Systems: Types, Functions, and Selection

In biomass power generation systems, industrial overhead cranes play a crucial role. This article introduces the various types of overhead cranes used in biomass power generation systems, their main functions, and the important considerations for selecting the appropriate equipment.

Classification of Straw and Biomass Power Generation Process

Classification of Straw

Biomass fuels are mainly divided into two categories: one is called “gray straw,” which includes materials such as cotton stalks, soybean stems, rapeseed straw, reeds, mulberry twigs, forest by-products, and wood processing scraps. After being crushed, gray straw has a relatively large bulk density. Gray straw is generally collected by purchasing the crushed fuel from society. It comes in various types and has a wide range of moisture content, often containing small amounts of construction waste and household garbage.

The other category is called “yellow straw,” which mainly includes wheat, corn, rice, and grasses. The bale bulk density ranges from 200 to 350 kg/m³, and the bulk density of crushed fuel ranges from 35 to 120 kg/m³. Most of this biomass fuel is stored and crushed at field packing plants.

Biomass Power Generation Process

The scale of most biomass power plants is below 30 MW, and the biomass power generation process typically involves the following steps: Biomass is collected using vehicles and transported to the power plant. Upon arrival, the biomass fuel is unloaded, handled, and dumped using a straw bale handling crane or a loose straw grab crane. These cranes move the biomass fuel to the fuel storage area and feed it into the fuel inlet. The fuel is then transported to the boiler storage chamber through equipment such as crushers and conveyors located below the inlet. The fuel is conveyed into the boiler for combustion via the shredder at the bottom of the storage chamber. The steam generated by biomass combustion drives a turbine and generator, producing electricity.

Structure and Function of Overhead Cranes in Biomass Power Generation Systems

Straw Bale Handling Crane

The straw bale handling crane mainly consists of the bridge frame, trolley running mechanism, complete trolley assembly, electrical room, operator’s cabin, conductive system, and specialized grab attachments. It is primarily used for the unloading, grabbing, stacking, dumping, and feeding of baled straw.

The operating principle is as follows: First, the straw bales on the truck are grabbed and transported to the stacking area. The straw bales need to be stored for approximately seven days before being placed onto the conveyor chain trigger by the straw bale handling crane. During operations such as unloading, grabbing, stacking, dumping, and feeding, the process is not continuous but must be adjusted based on the boiler’s operational status and the timing of the straw bale’s entry into the storage area. The crane’s actions are performed in an interleaved manner, depending on these factors.

Loose Straw Grab Crane

The main structure of the loose straw grab crane includes the bridge frame or gantry, trolley running mechanism, complete trolley assembly, electrical room, operator’s cabin, conductive system, and grab bucket. It is primarily used for unloading, grabbing, stacking, and feeding loose straw.

The operating principle is as follows: The loose straw grab crane first grabs and transports the loose straw from the truck to the stacking area. The straw is stored for several days before being fed into the fuel inlet from the stacking area using the crane. During operations such as unloading, grabbing, stacking, dumping, and feeding, the process is not continuous. Instead, it is performed in an interleaved manner, depending on the boiler’s operating status and the timing of the straw’s entry into the storage area.

Turbine Hall Crane

The main structure of the turbine hall crane includes the bridge frame, trolley running mechanism, complete trolley assembly, electrical room, operator’s cabin, conductive system, and hook. It is primarily used for the installation and maintenance of turbines and generators.

The operating principle is as follows: Due to their large size and weight, turbines and generators are transported to biomass power plants in separate components from the manufacturing facility. The turbine hall crane is used to lift and install these components. After installation, the turbine hall crane is typically used once a year for the maintenance and servicing of the turbine and generator.

Hoist Crane

The hoist crane primarily consists of the steel structure, lifting mechanism, running mechanism, and electrical control system, with the characteristic feature being the use of an electric hoist in the lifting mechanism.

• Steel Structure: Made of basic components like profiles or steel plates, the steel structure is welded or bolted together according to specific design principles, forming a structure that can bear the crane’s load. This is referred to as the crane’s steel structure.
• Mechanism: A combination of various devices that effectively perform the required actions is known as the mechanism.
• Electrical Control System: The electrical control system includes electrical circuits, components, and power supply connections.

The hoist crane is classified into three types:

• Crane ya Monorail: Primarily used for the maintenance and repair of boilers, flue gas equipment, and induced draft fans.
• Electric Single Girder Crane: Mainly used for maintenance and repair in machine repair workshops and circulating pump rooms.
• Electric Single-Girder Suspended Hoist Crane: Primarily used for maintenance and repair in integrated pump rooms.

Selection of Overhead Cranes in Biomass Power Generation Systems

Selection of Straw Bale Handling Crane

The role of the straw bale handling crane is crucial in biomass power generation systems, so it is essential to correctly select this crane based on the scale and process requirements of the biomass power generation system. The factors that influence the selection of a straw bale handling crane include:

• Biomass power generation fuel storage process (currently, there are two types of biomass fuel storage processes: loose straw and baled straw storage processes)
• Quality of straw bales (moisture content, calorific value, bulk density)
• Total daily biomass requirement (considering both the quality of biomass fuel and future modifications to the biomass power generation system)
• Number of fuel storage bins
• Size and weight of the straw bales
• Whether the straw bales are inspected

Generally, one to two straw bale handling cranes are arranged above a biomass fuel storage bay.

Selection of Loose Straw Grab Crane

The loose straw grab crane is an important piece of equipment in biomass power generation. The loose straw grab crane mainly consists of gantry grab cranes and overhead grab cranes. The factors influencing the selection of a loose straw grab crane include:

• Biomass power generation fuel storage process (currently, there are two types of biomass fuel storage processes: loose straw and baled straw storage processes)
• Quality of loose straw (moisture content, calorific value, bulk density)
• Total daily biomass requirement (considering both the quality of biomass fuel and future modifications to the biomass power generation system)
• Unloading time for loose straw
• Whether the loose straw is stored in a fuel shed or in the open

Selection of Turbine Hall Crane

The turbine hall crane is essential for the lifting and transportation of turbines and generators during installation and for normal maintenance operations. The selection of the turbine hall crane is crucial. The factors influencing the selection of the turbine hall crane include:

• Maximum single component weight in turbine and generator design
• Total number of turbine and generator units
• Whether additional auxiliary equipment is required for the installation of turbines and generators

Based on years of accumulated experience, biomass power generation systems generally have a unit capacity of below 30 MW and typically have fewer than three units. A single turbine hall crane is usually selected. However, if the number of units exceeds three, two turbine hall cranes (one large and one small) may be selected. The turbine hall cranes are typically arranged above the turbines and generators. The operation modes include both cabin operation and ground operation, with the operator’s cabin located below the crane body. The cabin and conductive system can be arranged on the same side or symmetrically.

Selection of Hoist Crane

The selection of a hoist crane mainly depends on the maximum single component weight in the installation system and the required lifting height.

Hitimisho

In conclusion, industrial cranes such as the straw bale handling crane, loose straw grab crane, turbine hall crane, and hoist crane play a vital role in biomass power generation systems. The reliability of these cranes directly affects the normal operation of the entire biomass power plant. However, the external working environment for industrial cranes is extremely harsh, with challenges such as high dust concentration, extremely high temperatures, and high alkalinity. Therefore, when designing and selecting these industrial cranes, it is essential to consider these special working conditions to ensure the durability and safety of the equipment.

Through proper design and selection of industrial cranes, the operational efficiency and safety of the biomass power plant can be effectively improved, avoiding production stoppages caused by equipment failures. It is hoped that this article will serve as a reference for engineers in the relevant fields, contributing to the safe and reliable operation of biomass power plants.

References: Industrial Cranes in Biomass Power Generation Systems

Cindy

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Barua pepe: cindywang@hndfcrane.com

Mimi ni Cindy, nina uzoefu wa miaka 10 katika tasnia ya kreni na nimekusanya maarifa mengi ya kitaaluma. Nimechagua korongo za kuridhisha kwa wateja 500+. Ikiwa una mahitaji yoyote au maswali kuhusu cranes, tafadhali jisikie huru kuwasiliana nami, nitatumia ujuzi wangu na uzoefu wa vitendo kukusaidia kutatua tatizo!