Waste to Solid Recovered Fuel (SRF) Processing Steps

1. Waste Collection and Reception

Objective: Gather and preliminarily sort waste.

• Source Collection: Waste is collected from municipal, commercial, or industrial sources.
• Reception Facility: Waste is delivered to a processing plant where it is weighed, inspected, and stored temporarily.

2. Pre-sorting

Objective: Remove large, non-combustible, and hazardous items.

• Manual Sorting: Workers remove large and obvious contaminants like metals, glass, and large plastics.
• Mechanical Sorting: Equipment such as shredders, screens, and magnets further separate materials.

3. Screening and Separating

Objective: Separate materials by size to ensure consistent fuel quality.

• Trommel Screens: Rotating drums with perforated screens classify materials based on size.
• Vibratory Screens: Use vibration to separate finer materials from larger items.

4. Air Classifiers

Objective: Separate materials based on density to remove non-combustibles.

• Positive pressure blow type density sorting: Positive pressure blow type density sorting is a method that uses controlled air flow to separate materials based on their density. In this process, waste materials enter a separation chamber where a powerful stream of air is directed at them. Lighter materials, such as plastics and paper, are blown away by the air stream into a collection area, while heavier materials, such as metals and glass, fall into a different collection area due to their greater density. This efficient and effective technique is widely used in recycling plants and waste processing facilities to enhance the purity of recyclable streams and improve overall recycling rates.
• Negative pressure suction type density sorting: Negative pressure suction type density sorting is a method that uses controlled suction to separate materials based on their density. In this process, waste materials enter a separation chamber where a powerful vacuum is applied. Lighter materials, such as plastics and paper, are sucked upwards or towards a collection area by the vacuum, while heavier materials, such as metals and glass, remain unaffected and fall into a separate collection area due to their higher density. This efficient and effective technique is commonly used in recycling plants and waste processing facilities to improve the purity of recyclable streams and enhance overall recycling rates.

5. Magnetic and Eddy Current Separation

Objective: Remove ferrous and non-ferrous metals.

• Magnetic Separators: Extract ferrous metals using powerful magnets.
• Eddy Current Separators: Use magnetic fields to separate non-ferrous metals like aluminum.

6. Refining and Purifying

Objective: Enhance fuel quality by removing remaining contaminants.

• Optical Sorting: Uses cameras and sensors to identify and remove unwanted materials.
• Additional Shredding: Further reduces particle size and homogenizes the material.

7. Shredding

Objective: Reduce waste particle size to facilitate further processing and improve combustion properties.

• Primary Shredding: Initial shredding breaks down large pieces of waste into smaller, more manageable sizes.
• Secondary Shredding: Secondary shredding ensures uniform particle size, enhancing fuel quality and consistency.
• Fine Shredding:Usually shredding SRF size to less than 50 mm

8. Drying

Objective: Reduce moisture content to improve combustion efficiency.

• Rotary Dryers: Large rotating drums that use heat to evaporate moisture.
• Belt Dryers: Convey waste on a perforated belt through a heated chamber.

9. Baling

Objective: Convert processed material into a uniform fuel format.

• Baling Machines: Compress waste into bales for storage and transport.

10. Quality Control

Objective: Ensure the final SRF meets required standards for calorific value, moisture content, and contaminant levels.

• Sampling and Testing: Regularly test samples for key parameters.
• Adjustments: Modify processing parameters based on test results to maintain quality.

11. Storage and Transportation

Objective: Safely store and transport SRF to end-users.

• Storage Facilities: Use silos, warehouses, or covered storage areas to protect SRF from moisture and contamination.
• Transportation: Utilize covered trucks, railcars, or ships to transport SRF to cement kilns, power plants, or other end-users.