Continuing global energy consumption, population growth, and accelerated urbanization force us to seek new solutions to the challenges of traditional fossil fuel shortages. Alternative fuels (RDF/SRF) can not only meet our demand for energy, but also convert combustible solid waste into energy and realize resource recycling.
Importance of calorific value of alternative fuels: The calorific value is an important indicator of fuel quality. The higher the calorific value, the more heat is generated when the fuel is burned. RDF/SRF screens and crushes combustible materials in garbage (such as plastics, fibers, rubber, wood, food waste, etc.) to make alternative fuels. Since most of the inert matter has been removed, the calorific value of the fuel has been greatly increased. In the ENISO21640:2021 standard, the classification of SRF is defined based on the range of calorific value, chlorine content and mercury content. The calorific value of SRF is about 18MJ/Kg, and the calorific value of high-quality SRF can reach 20MJ/Kg. The calorific value of RDF is generally about 23MJ/kg, which is similar to the calorific value of coal.
Comparison table of calorific value of fossil and alternative fuels:
| Fuel | Calorific value | Generate CO2/ton of fuel |
| Coal | 25MJ/kg | 2.41 |
| Petroleum coke | 33MJ/kg | 3.34 |
| Fuel | 42MJ/kg | 3.16 |
| SRF | 20MJ/kg | 0.64 |
Table of alternative fuel volume per unit of coal and carbon dioxide emissions:
| SRF | SRF | SRF | COAL | |
| Low calorific value (MJ/kg) | 12 | 15 | 18 | 25 |
| Required amount of substitution | 210% | 170% | 140% | 100% |
| Fossil CO2 emissions | ~30% | ~30% | ~30% | 100% |
Production line process flow chart:
● Power generation project: It is very economical to mix RDF and coal to generate electricity in thermal power plants.
● District heating projects: In areas with relatively complete heating infrastructure, RDF heating can be achieved by building specialized RDF combustion boilers with less investment.
● Cement kiln co-processing: Utilize RDF combustion ash as a raw material in cement manufacturing, thus eliminating the RDF combustion ash treatment process and reducing operating costs.
● Drying process: RDF is burned in a special boiler and used as a heat source for drying and thermal deodorization.
● Small and medium-sized public places: Mainly refers to heated swimming pools, gymnasiums, hospitals, public baths, welfare homes for the elderly, melting snow, etc.
● Application as carbide: The RDF is pyrolyzed and carbonized in the presence of air isolation, and the flammable gas produced is burned and used as a heat source for the drying project. The pyrolysis residue is carbide, which can be used as a reducing agent in the ironmaking blast furnace.
