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Heavy Oil Refining Complete Process / Distillate Oil Deacidification

Distillate Oil Deacidification Complete Process
Integrated Complexation Deacidification & Resource Recovery · Acid Value Stably Below 1.0 mgKOH/g

Deep naphthenic acid removal under mild conditions (80-85℃, atmospheric pressure) — not just anti-corrosion deacidification, but turning naphthenic acid into a resource: closed-loop chemical recovery and a profitable by-product turn deacidification from a cost center into a profit center

📋 Request a Deacidification Project Proposal Talk to a Process Engineer
🧪 Proprietary Complexing Deacidification Agent
📉 Acid Value 5.0+ → <1.0 mgKOH/g
♻️ Closed-Loop Agent/Solvent Recovery
💰 Naphthenic Acid By-Product Resourcing

Four Pain Points of High-Acid-Value Crude Processing

🛠️ Severe Equipment Corrosion

Naphthenic acid corrosion runs through the entire refining process, threatening long-cycle safe operation and driving up maintenance costs.

⚙️ High Processing Difficulty

A high acid value makes electric desalting demulsification difficult, with high calcium, iron and sodium salt content disrupting steady downstream operation and product quality.

🌊 Environmental & Cost Pressure

Traditional caustic-wash electric refining deacidification generates acidic wastewater that is difficult and costly to treat, and the valuable naphthenic acid is not recovered.

📉 Poor Economics

High chemical consumption becomes a fixed cost, by-product value goes untapped, and overall processing profitability is limited.

Core Process: High-Efficiency Complexation Settling Deacidification

Using a proprietary complexing deacidification agent, under mild conditions (80-85℃, atmospheric pressure) it undergoes a selective complexation reaction with the naphthenic acid in crude distillate fractions (such as gas oil and diesel); the resulting complex derivative is removed by settling separation.

  • 🔄 Simple, efficient process: feedstock oil, deacidification agent and solvent are mixed through a static mixer, then separated by settling in an insulated tank — easy to operate
  • 📉 Deep deacidification: distillate oil with an acid value above 5.0 mgKOH/g can be stably reduced below 1.0 mgKOH/g, significantly easing downstream corrosion
  • ⏱️ Continuous operation: twin settling tanks alternate through a "feed – settle – discharge" cycle, keeping downstream feed steady (e.g. stable at 25 tonnes/hour)
  • 🎛️ Flexible adaptation: applicable to diesel, gas oil and mixed distillates, with dosage adjusted flexibly to feed acid value

Sample Key Parameters (200,000-Tonne/Year Unit)

ItemValue
Unit capacity200,000 tonnes/year
Operating temperature80-85℃ (atmospheric)
Distillate oil acid valueAbove 5.0 mgKOH/g
Post-treatment acid value<1.0 mgKOH/g
Refined oil yield≥92%
Feed stability25 tonnes/hour (twin-tank alternating)

Temperature, flow, level and dosing are all under automated control for stable operation. Core equipment: dedicated settling tanks, static mixer, precision metering injection system, complex transfer pump, and flash tower (for residual solvent recovery).

Core Advantage: Closed-Loop Resource Recovery System

This is what sets this technology package apart from traditional deacidification — it goes beyond separating out naphthenic acid to achieve recycling and value creation across the whole material system, turning deacidification from a "pure cost" into a "profit center."

♻️ Efficient Agent & Solvent Recovery

The complex derivative is processed through acidification, neutralization, distillation, extraction and electrodialysis, achieving deacidification agent recovery ≥85% and solvent recovery ≥95%; recycling these directly lowers per-tonne processing cost and cuts hazardous waste at the source.

🌱 Zero Solid Waste

The deacidification and recovery process generates no solid waste, with no environmental compliance burden.

🧴 High-Purity Naphthenic Acid Refining

Crude naphthenic acid is separated, acidified, washed and dehydrated from the complex derivative for further refining. Naphthenic acid is an important chemical raw material (additives, catalysts, surfactants, etc.), converting directly into economic value.

Distillate Oil Deacidification FAQ

Why does high-acid-value crude oil need deacidification?
Naphthenic acid corrosion runs through the entire refining process, threatening long-cycle safe operation and driving up maintenance costs; a high acid value also makes electric desalting demulsification difficult and raises metal salt content, disrupting steady downstream operation and product quality. Deacidification lowers feedstock acid value and significantly eases downstream corrosion. For protecting existing high-temperature sections, this can be paired with a phosphorus-free high-temperature inhibitor.
How is complexation deacidification different from traditional caustic washing?
Traditional processes such as caustic washing and electric refining generate acidic wastewater that is difficult and costly to treat, and the naphthenic acid resource is not recovered. Complexation deacidification runs under mild conditions (80-85℃, atmospheric pressure) — static mixing plus insulated settling is all it takes to separate, a simple process paired with a closed-loop resource recovery system that recovers the deacidification agent, solvent and naphthenic acid by-product, with no solid waste generated.
How low can the acid value go, and what is the yield?
Distillate oil with an acid value above 5.0 mgKOH/g can be stably reduced below 1.0 mgKOH/g; refined oil yield is ≥92% (based on a 200,000-tonne/year unit), with agent dosage adjusted flexibly to feed acid value.
What feedstocks does it apply to? Can it run continuously?
It applies to diesel, gas oil and mixed distillates, and is especially suited to refineries processing high-acid-value feedstock. Twin settling tanks alternate through a "feed – settle – discharge" cycle to keep downstream feed steady, with the whole process under automated control.
What value does the recovered naphthenic acid have?
Deacidification agent recovery ≥85% and solvent recovery ≥95%; recycling directly lowers per-tonne cost, and the process generates no solid waste. The separated naphthenic acid can be refined and sold as a chemical raw material, or further synthesized into naphthenic acid amide (drilling emulsifier) or naphthenic acid imidazoline (corrosion inhibitor) for additional profit.

Distillate Oil Deacidification Project Inquiry

Share your feedstock oil's acid value and other properties, and our technical team will provide a tailored deacidification proposal, economic analysis, and bench evaluation