RDF (Refused-Derived Fuel) refers to solid fuel derived from combustible materials separated from municipal solid waste through a series of processing steps.
The appeal of waste-derived fuel technology lies in its ability to convert municipal waste into efficient, clean fuel. This technology provides a new pathway for the resource utilization of waste.
Refused derived fuel
It not only solves the waste disposal problem but also transforms waste into usable energy, realizing a circular economy model of waste resource recovery.
I. Refused derived fuel(RDF) Classification and Forms
The American Society for Testing and Materials (ASTM) classifies RDF into seven categories based on processing degree and shape:
RDF-1: Raw municipal solid waste with simple processing
RDF-2: Waste coarsely crushed to remove metals and glass
RDF-3: Further crushed to particles smaller than 2 inches after removing inorganic matter
RDF-4: Powdered combustible material passing through a 0.035-inch sieve
RDF-5: Compacted pellet, spherical, or brick-shaped fuel
RDF-6: Liquid waste-derived fuel
RDF-7: Gaseous waste-derived fuel
Among these, RDF-5 is currently the most widely used form due to its ease of transportation and storage, high calorific value, and stable combustion.
II. Refused derived fuel Production Process
The Refused derived fuel production process mainly includes four stages: Shredding, sorting, drying, and forming.
In a typical separation and processing system, municipal solid waste first passes through a trommel screen to remove glass and soil; the remaining portion is then conveyed to a shredder for crushing.
Shredded waste passes through an Air Separator to separate the lightweight components (plastics, paper, wood, textiles, etc.) from the heavyweight components (metals, aluminum, and small amounts of glass and ceramics).
The lightweight components, after ferrous metals are removed by a magnetic separation system, can be used as fuel. The heavyweight components undergo further metal recovery, and the remainder is sent to landfills.
III. Technical Advantages of RDF
1. Excellent corrosion resistance: With a moisture content below 10%, it can be stored indoors for one year without spoiling after the addition of calcium compound additives.
2. High and stable calorific value: The calorific value is between 14600 and 21000 kJ/kg. Its uniform shape promotes stable combustion and improves efficiency.
3. Superior environmental performance: Since chlorinated plastics constitute only a portion, and lime is added for in-furnace dechlorination, chloride gas production is suppressed, significantly reducing emissions of pollutants such as dioxins.
4. Flexible operation: RDF production is not limited by site or scale, can be bagged for transportation, and is easy to manage.
IV. Application Areas of RDF
RDF molded finished products
1. Heating Engineering: RDF can be used in district heating systems to provide heating and hot water to buildings.
2. Power Generation Engineering: RDF has a high and stable calorific value, making it particularly suitable for power generation, with higher combustion and power generation efficiencies than traditional waste-to-energy plants.
3. Cement Industry: RDF can serve as an alternative fuel for cement rotary kilns, and the mineral components in its ash can also be beneficial raw materials for cement production.
4. Drying Engineering: Industrial drying processes require a large amount of heat energy, and RDF can provide an economical heat source.
RDF technology transforms waste from a treatment problem into an energy solution. With the promotion of waste sorting policies and technological advancements, RDF will play an increasingly important role in urban solid waste management and energy structure.
Waste is a resource in the wrong place, and RDF technology is the best embodiment of this concept.