Can Waste Plastic Be Refined into Diesel?

Can Waste Plastic Be Refined into Diesel?

Yes, waste plastic can be refined into diesel, but this requires strict compliance with environmental, safety, and industrial policy requirements. Here are the key points:

I. Technical Feasibility

Pyrolysis Principle: Under oxygen-free or oxygen-deficient high-temperature conditions (400–600°C), chlorine-free plastics such as polyethylene (PE) and polypropylene (PP) undergo cracking to produce an oil-gas mixture. After condensation and separation, crude fuel oil is obtained.

Refining Process: Crude oil is further treated through hydroprocessing or catalytic cracking to remove sulfur, nitrogen, heavy metals, and other impurities, yielding diesel, gasoline, and other finished fuels that meet quality standards.

II. Key Constraints

Raw Material Restrictions: Only chlorine-free plastics (PE, PP, PS, etc.) are suitable. Mixing in polyvinyl chloride (PVC) is strictly prohibited, as it generates highly toxic hydrogen chloride gas, which severely corrodes equipment and pollutes the environment.

Environmental Requirements: An efficient exhaust gas purification system must be installed to treat pollutants like dioxins and VOCs generated during pyrolysis, ensuring emissions comply with the Emission Standard for Pollutants from Synthetic Resin Industry.

Policy Compliance: This is a state-encouraged resource recycling project, but it requires EIA approval. Backward processes such as "crude oil refining" are strictly prohibited, and non-compliant operations face shutdown penalties.

III. Risks and Considerations

Safety Risks: Combustible gases produced during pyrolysis pose an explosion hazard. Safety systems like nitrogen protection and pressure interlocks are mandatory.

Cost and Profitability: High equipment investment and operational costs make this viable only for large-scale, professional compliant enterprises. Small workshop-style operations are not economically feasible.

Product Quality: Crude fuel oil without deep refining has high sulfur and impurity content, which damages engines. It must meet finished fuel quality standards before use.