Technical Challenges of Refining Diesel from Waste Plastic

Technical Challenges of Refining Diesel from Waste Plastic

The industrial implementation of diesel production from waste plastic faces multiple technical challenges, with the core difficulties summarized as follows:

I. Raw Material Pretreatment

Complex Composition and Difficult Sorting: Mixed plastics contain harmful impurities such as PVC. Manual sorting is inefficient, while automated sorting is costly and has limited accuracy.

High Impurity Treatment Costs: Impurities like sediment and oil easily cause equipment wear and coking, requiring multi-stage pretreatment that results in high energy consumption and maintenance costs.

II. Pyrolysis Reaction Control

Poor Reaction Stability: Different plastics have significantly different cracking temperatures, so mixed raw materials tend to cause furnace temperature fluctuations and local overheating, reducing product yield.

Risk of Coking and Carbon Deposition: Macromolecular polymers easily coke on furnace walls, reducing thermal efficiency and blocking equipment, which requires frequent shutdowns for cleaning.

III. Oil Refining

High Difficulty in Impurity Removal: Crude oil contains impurities such as sulfur, nitrogen, and chlorine, requiring deep processing like hydrorefining, which involves large investment and high energy consumption.

Difficulty in Product Regulation: The composition of pyrolysis oil fluctuates greatly; precise control of reaction parameters is needed to directionally produce diesel fractions that meet standards.

IV. Environmental Protection and Safety

High Requirements for Pollutant Treatment: An efficient purification system must be installed to handle highly toxic gases such as dioxins and hydrogen chloride, resulting in high equipment costs.

Prominent Safety Risks: Combustible gases easily form explosive mixtures, requiring devices like nitrogen protection and pressure interlocks, which demand a high level of automation.

V. Economic Feasibility

Difficulty in Cost Control: The high costs of pretreatment, pyrolysis, and refining, combined with unstable raw material supply or oil price fluctuations, can easily lead to insufficient returns.

High Compliance Threshold: Projects must pass EIA, safety evaluation, and other approvals. Small enterprises struggle to bear compliance costs, and large-scale production is limited by site availability.