Key Precautions for Waste Plastic Oil Refining

Waste plastic oil refining (pyrolysis/catalytic cracking) is a high-risk, heavily regulated, technology-intensive resource recycling project. Core precautions cover six major aspects: legal compliance, production safety, raw material control, process stability, environmental protection compliance, and oil product quality. Negligence in any link may lead to safety accidents, environmental penalties or project losses.

1. Legal Compliance Procedures (Project Lifeline)

Complete all formalities without omission:

1. Project Approval & EIA: Complete development and reform commission filing, environmental impact assessment approval, and pollutant discharge permit. Strictly follow HJ 364-2022 Technical Specification for Pollution Control of Waste Plastics.

2. Land & Planning: Use industrial land and comply with park planning and safety distance requirements.

3. Safety Approval: Obtain the Safety Production License and complete the Three Simultaneities safety review (design, construction, commissioning).

4. Hazardous Waste Management: Cracking residue, waste catalysts and other hazardous wastes must be disposed of by qualified institutions.

5. Product Standards: Cracked crude oil must be refined to meet standards; substandard oil shall be managed as hazardous waste.

   
   

2. Production Safety (Top Priority)

Cracking operates under high temperature, slightly high pressure, flammable and explosive conditions with extreme risks:

• Prevent oxygen ingress strictly: Maintain oxygen-free / slight positive pressure cracking. The feeding and slagging system must be fully sealed, equipped with nitrogen replacement and pressure monitoring devices to avoid flash explosion.

• Precise temperature control:

• Optimal temperature: 350℃ ~ 450℃.

• Low temperature: incomplete cracking and low oil yield; High temperature: raw material carbonization and coking, oil-gas boiling and equipment overpressure.

• Anti-corrosion (Critical Risk):

• Strictly ban PVC (Polyvinyl Chloride)! PVC decomposes into hydrogen chloride at high temperature, causing severe equipment corrosion and possible production of dioxins (highly toxic carcinogens).

• Equipment shall adopt high temperature and corrosion resistant steel such as 310S, 316L.

• Explosion-proof & Fire Protection: Plant explosion-proof design, equipped with combustible gas alarm, fire hydrant, dry powder fire extinguisher and emergency sump.

• Certified Personnel: Operators must receive professional training, hold valid certificates and strictly follow operating procedures.

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3. Raw Material Pretreatment (Key to Success)

Raw materials directly determine oil yield, oil quality and service life of equipment:

1. Strict Sorting

• Preferred materials: PE (Polyethylene), PP (Polypropylene), PS (Polystyrene), oil yield 50%-90%.

• Rejected materials: PVC, PET (Polyester), rubber, metal, sediment, paper and other impurities.

• Glue removal: Remove adhesive tapes and labels to prevent coking.

1. Crushing & Drying

• Crush into 5-10cm fragments for uniform heating.

• Dry to moisture content ＜ 8%. Excess moisture consumes massive heat, lowers temperature, produces wastewater and even causes bumping explosion.

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4. Core Process & Equipment Operation

1. Cracking ReactorChoose formal manufacturer’s batch, semi-continuous or fully continuous cracking furnace. Ensure good sealing performance, thermal insulation and stirring/pushing system to avoid local overheating and coking.

2. Condensation SystemAdopt multi-stage condensation (shell & tube + spray type) to fully liquefy oil gas.Prevent wax blockage: PE/PP cracking easily produces paraffin wax blocking pipelines; support with heat tracing, wax cleaning and scraping devices.

3. Tail Gas RecyclingNon-condensable combustible gas produced by cracking shall be recycled as heating fuel, saving energy and reducing pollution.Tail gas must be discharged up to standard after secondary combustion (above 800℃), desulfurization and dedusting.

   
   

5. Environmental Protection & Three Waste Treatment (Compliance Bottom Line)

Environmental protection investment usually accounts for over 30% of total investment:

• Waste Gas: Cracking flue gas, non-condensable gas and tank volatile gas. Treatment process: desulfurization tower + activated carbon adsorption + photo-oxygen catalysis, discharge up to standard.

• Wastewater: Raw material cleaning water, condensed water and floor washing water. Reuse after treatment to achieve near zero discharge.

• Waste Residue: Coking carbon residue and waste catalyst are classified as hazardous waste, requiring compliant disposal or comprehensive utilization (activated carbon production, building materials, etc.).

• Noise Reduction: Noise reduction treatment for fans and pumps to meet factory boundary standards.

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6. Oil Quality & Market Sales

• Crude Oil Refining: The cracked product is crude heavy oil, which needs distillation, desulfurization, deacidification and decolorization to be upgraded as fuel oil or further processed in refineries.

• Market Guarantee: Pre-negotiate supply with boiler factories, refineries and distributors to ensure compliant sales of oil products.

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7. Daily Operation & Maintenance Tips

• Regular Decoking: Coking easily forms on furnace inner wall and pipelines; shut down regularly for cleaning to guarantee heat transfer efficiency.

• Equipment Inspection: Focus on checking sealing, temperature, pressure, valves and instruments to prevent running, overflowing, dripping and leaking.

• Ledger Records: Keep complete records of raw materials, production, environmental protection and safety data for regulatory inspection.

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