Complete Set of Waste Engine Oil to Diesel Refining Equipment

Lubricating oils are widely used in all types of machinery and equipment. During service, they accumulate dust, mechanical impurities and water. Meanwhile, exposure to high temperatures and oxidation generates various oxidized intermediates and organic compounds, turning the oil black, lowering its viscosity and degrading its quality to form waste engine oil. Discarding waste engine oil not only pollutes the environment but also wastes massive recyclable resources.

The new technology for producing diesel from waste engine oil through pyrolysis turns waste into valuable products, delivering an economic profit margin of 10% to 200%, while protecting the environment. This project is an eco-friendly green initiative beneficial to both the country and the public. It requires low upfront investment, features simple operation and boasts high promotion value.

In the early days, foreign countries also adopted the acid-clay refining process. Its core advantages include convenient separation of additives from oil and low capital investment. This process has not been fully phased out and is still widely deployed in many nations. However, it has obvious drawbacks that place it on the verge of elimination: it causes severe secondary pollution, including large volumes of acidic gas such as hydrogen sulfide (H₂S), plus troublesome acid sludge, acid wastewater and waste clay residue. These pollutants harm operators’ physical and mental health, corrode equipment and contaminate the surrounding environment.

IFP Process

This process uses propane to extract impurities from waste oil. After this pretreatment, two major benefits are achieved: the consumption of sulfuric acid and bleaching clay in the subsequent sulfuric acid refining stage is drastically reduced.

Our Core Advantages

1. Patented Circulating Catalytic Cracking Technology

Our factory has developed an original circulating catalytic cracking process based on in-depth research into waste lubricating oil.

Lubricating oil is derived from vacuum distillate oil, characterized by heavy fractions and large molecular weights. Conventional distillation cannot produce light distillates similar to light diesel.

We cooperate with top domestic catalyst manufacturers (Qilu Petrochemical Catalyst Factory) and petrochemical research institutes. Custom composite catalysts exclusively for waste lubricating oil are developed via domestic advanced synthesis technology to realize synergistic gas-liquid catalysis.

Under medium-low temperature reaction conditions, hydrocarbon molecules are easily cleaved into short chains. The dominant reaction is cracking, accompanied by isomerization, hydrogen transfer, aromatization and other side reactions.

The cracking rate sequence of various hydrocarbons: Olefins > Cycloalkanes & Isoalkanes > Normal alkanes > Aromatics.

2. Advanced Control System

This is a fully automatic continuous production unit equipped with a DCS control system that precisely regulates temperatures at furnace outlets, tower tops and all side draw outlets.

Basic Control Principles

The distillation of waste engine oil is essentially a physical gas-liquid phase conversion process. All control logics comply with fundamental principles including mass balance, heat balance, phase equilibrium, mass transfer and heat transfer.

(1) Balanced Temperature Control for Heating Furnace Branch Outlets

Feedstock for atmospheric furnaces is split into multiple branches. Traditional control installs automatic flow transmitters and regulating valves on each branch, and adjusts furnace fuel supply based on the mixed outlet temperature of all branches. This method only stabilizes the overall furnace outlet temperature while allowing wide temperature fluctuations across individual branches, which risks overheating and coking inside certain furnace tubes.

To solve this problem, we adopt branch balanced temperature control as shown in Figure 4. The total furnace feed flow is kept constant while branch flow rates are adjustable. The outlet temperature of each branch is automatically compared against the overall furnace outlet temperature, and the feed flow of every branch is dynamically calculated and adjusted to equalize branch temperatures.

With DCS, FDB modules conveniently implement this balanced control, limiting temperature deviation to ≤1℃, and even below 0.5℃ under stable operating conditions.

(2) Heating Furnace Combustion Control

In conventional control systems, independent variables such as furnace outlet temperature, furnace negative pressure and flue gas composition operate without interconnection, despite inherent mutual interference.

Our DCS applies feedforward-feedback compound control: furnace thermal efficiency is the feedback control object, air volume adjustment serves as the execution means, and fuel pressure is selected as the interference source for single-parameter feedforward regulation. The control flow is illustrated in Figure 5.

(3) Closed-Loop Quality Control for Fractionating Towers

This control logic relies on real-time operational parameters including calibrated true boiling point curves, boiling point curves of side-draw products, temperature and pressure at all tower sections, and inlet/outlet stream flow rates.

Mass and heat balance calculations derive internal gas-liquid reflux volumes and compositions in each tower section, then compute the initial boiling point and dry point of side-draw products, which are set as temperature control targets.

The Suny Tech TDCS9200 system easily implements this function via RTM function blocks. It replaces online analytical instruments and eliminates measurement lag, enabling real-time detection of dry point fluctuations and automatic adjustment of product draw rates to stabilize product quality and improve oil yield.

(4) Multivariable Intelligent Control for Atmospheric Towers

Multiple single-loop PID controllers can be integrated into comprehensive control for individual equipment or full process segments. Leveraging DCS computing and control functions paired with process mathematical models, we develop customized advanced and optimized control strategies that generate substantial economic benefits.

As shown in Figure 6, multivariable intelligent control for atmospheric towers delivers outstanding performance in stabilizing operation, offsetting feedstock disturbances, counteracting furnace outlet temperature fluctuations and upgrading product quality.

Controlled variables: Atmospheric tower top temperature, gas-phase temperature of the 1st side draw, gas-phase temperature of the 3rd side draw

Manipulated variables: Cold reflux flow at tower top, draw flow of the 1st side line, draw flow of the 3rd side line

Measurable disturbance variables: Heating furnace outlet temperature, tower top pressure

(5) Overflash Rate Control

Waste lubricating oil distillation requires a moderate overflash rate to guarantee distillate yield and quality. Excessively high overflash increases unit energy consumption; the optimal range is 2%–3%. DCS supports closed-loop automatic control or open-loop guidance for overflash rate regulation.

DCS automation for atmospheric-vacuum distillation units delivers remarkable economic and social benefits:

Intelligent and complex control improves product quality and light oil recovery rate;

Replacement of conventional discrete instruments reduces intermediate failure rates, extends safe equipment operation cycles, cuts unplanned shutdowns and increases effective production hours.

3. Newly Designed Fixed-Bed Catalytic Tower & Rectifying Tower

The unit is equipped with ADV® differential float valve trays, which possess prominent advantages over traditional F1 float valve trays:

Processing capacity increased by over 40%, separation efficiency improved by 10%, operating flexibility exceeding 40%;

Superior hydrodynamic mass transfer performance;

One of the industry’s high-throughput, high-efficiency tray types.

4. Strict Product Quality Control Standards

One-step finished oil production process with complete acid-free treatment, eliminating downstream pollution and redundant working procedures (slightly higher catalyst consumption may occur).

Conventional refining (decolorization & stabilization) is also available. We adopt advanced solvent extraction technology featuring shorter processing time, higher oil yield and purer oil odor.

Our Commitments

Provide integrated full-process waste lubricating oil treatment solutions.

Supply complete refining plants with annual capacities ranging from 10,000 tons to 1 million tons, alongside general engineering contracting services.

Full-lifecycle technical after-sales tracking. We offer on-site engineering services for clients in any country or region worldwide suitable for refinery construction.