Conveyor Systems for Waste Management

Conveyor systems are an integral component of waste management and recycling operations. It works for various types of materials and transports them to different locations.  They play a vital role in the process of sorting waste material and their movements.  Mixed wastes are arranged for inspection over a conveyor, which then moves it from one end to another. While on its way items are sorted and unwanted materials are removed.

Conveyors are also used for carrying recycling materials such as wood or paper wastes to their respective grinding and process centers. Waste conveyors are manufactured with materials that do not get damaged by constant exposure to abrasives. They are also not affected by sticky or greasy liquids and dirt. Belt conveyors and chain conveyors are the most commonly used conveyors in recycling plants.

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Mostly non-powered conveyors are used in the industry. However, powered belt and roller conveyors are sometimes used for handling small products. They are typically used for pallet handling.

Conveyors are also used for moving waste materials in long streams so that they can be separated. Vibrating belts are attached which separate materials that require inspection. Waste materials and recycling industry is mostly about dealing with contaminated products and trash. Thus additional cautions are considered for the safety and environmental standards of the workers.

Types of Conveyors

Conveyors vary in shapes and dimensions according to their utility. From being installed in biomass plants, waste sorting plants, material recovery facilities, waste-to-energy plants, to being a prime component at food processing facilities, paper industry, mining, and pharmaceutics, conveyors are used everywhere.

Even at tough job-sites where transfer of materials is required across steep inclinations or large distances conveyors can ease the process. Generally, they are classified as belt conveyors and screw conveyors.

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Screw Conveyors

Screw conveyors were invented by Archimedes and its core design hasn’t changed from its original design over these years. They can be vertical or horizontal with an entirely contained, metered space. Screw conveyors are generally used for moving dust-free movement of grains or flakes, powders, sludge, etc. They are made of galvanized metal, carbon steel, stainless steel, tapered screws, discharge chute, or in-feed hoppers.

Belt Conveyors

Belt conveyors have a wide-open frame which enables them to contain and move high loads of material over long distances. This is why they are commonly used in the mining industry and other places where heavy materials are required to be transported.  Structurally they are rugged loops that run over two or more pulleys. Additional rolls are also added in between to provide support in long belts.

Materials ranging from garbage to fine grains and powders and be carried over belt conveyors. They are also used for the movement of commercial waste including paper, plastic, or aluminum cans.

Belt material, configuration, and dimension differ according to its application. Various designs of belts are used nowadays, for example, magnetic belts, flat belts, trough belts, rubber belts, etc. Moreover, conveyors are also designed in shapes such as to carry fluids including sludge and water. Key manufacturing materials for these belts are cotton, canvas, leather, nylon, polyester, silicone, and steel. Dimension, design and materials can be easily customized depending on its application and to meet customer requirements.

Overview of Biomass Handling Equipment

The physical handling of biomass fuels during collection or at a processing plant can be challenging task, particularly for solid biomass. Biomass fuels tend to vary with density, moisture content and particle size and can also be corrosive. Therefore biomass fuel handling equipment is often a difficult part of a plant to adequately design, maintain and operate.

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The design and equipment choice for the fuel handling system, including preparation and refinement systems is carried out in accordance with the plant configuration. This is of special importance when the biomass is not homogeneous and contains impurities, typically for forest and agricultural wastes. Some of the common problems encountered have been the unpopular design and undersized fuel handling, preparation and feeding systems.

The fuel handling core systems and equipment are dependent on both the raw fuel type and condition as well as on the conversion/combustion technology employed. The core equipment in a biomass power plant include the following:

  1. Fuel reception
  2. Fuel weighing systems
  3. Receiving bunkers
  4. Bunker discharge systems (stoker, screw, grab bucket)
  5. Fuel preparation
  6. Fuel drying systems
  7. Crushers
  8. Chippers
  9. Screening systems
  10. Shredding systems
  11. Grinding systems (for pulverised fuel burners)
  12. Safety systems (explosion relieve, emergency discharge, fire detections etc)
  13. Fuel transport and feeding
  14. Push floors
  15. Belt feeders
  16. Conveyers and Elevators
  17. Tube feeders
  18. Fuel hoppers and silos (refined fuel)
  19. Hopper, bunker and silo discharge
  20. Feeding stokers
  21. Feeding screws
  22. Rotary valves

To enable any available biomass resource to be matched with the end use energy carrier required (heat, electricity or transport fuels) the correct selection of conversion technologies is required. Since the forms in which biomass can be used for energy are diverse, optimal resources, technologies and entire systems will be shaped by local conditions, both physical and socio-economic in nature.

As the majority of people in developing countries will continue using biomass as their primary energy source well into the next century, it is of critical importance that biomass-based energy truly can be modernized to yield multiple socioeconomic and environmental benefits.