Process Liquid Filtration for Petrochemical Industry

The petrochemical industry requires advanced filtration technologies to optimize processes, reduce contaminants, and improve efficiency. Below are the detailed filtration applications, focusing on liquids, water, and gases, with specific products used in each process.

1. Catalyst Recovery and Reaction Liquid Purification

Application: Recovery of precious metal catalysts (e.g., platinum, palladium) in processes such as ethylene cracking, catalytic reforming, and hydrodesulfurization.

Technical Solution:

· Ceramic Membrane Filtration (pore size: 0.1–0.5 µm): High-temperature resistance (up to 300°C), acid/base resistance (pH 2–12). Catalyst recovery rate ≥95%.

· Metal Sintered Filter (316L Stainless Steel): Filtration precision: 1–10 µm, suitable for high-pressure reactors.

Filtration Process:

1. Reaction liquid → Settling tank → Ceramic membrane filtration → Catalyst regeneration → Reuse of filtrate.

Industry Standard: API RP 934 (High-temperature and high-pressure equipment for refineries).

2. Solvent and Intermediate Refining

Application: Purification of aromatics (benzene, toluene) and olefins (ethylene, propylene), removing sulfur compounds, colloids, and moisture.

Technical Solution:

· Activated Carbon Adsorption Tower: Removes H₂S (desulfurization rate ≥99%), sulfur content ≤1 ppm.

· Molecular Sieve Dehydration System: Dew point ≤ -40°C to ensure polymerization reaction stability.

· Filtration Equipment: Bag filters (25 µm for pre-filtration) + Ultrafiltration Membrane (0.01 µm).

Case Study: A petrochemical company used a molecular sieve + ultrafiltration combination to increase propylene purity from 99.5% to 99.9%.

Filtration Process:

1. Solvent → Pre-filtration (bag filter) → Molecular sieve + Ultrafiltration → Purified solvent storage.

3. Acid Washing Wastewater and Process Water Treatment

Application: Treatment of acid washing wastewater (containing H₂SO₄, HF) and oil-contaminated wastewater from refining processes.

Technical Solution:

· Neutralization + Flotation System: pH adjustment to 6–9, removal of emulsified oils (oil content ≤5 ppm).

· Acid-Resistant Ceramic Membrane (Zirconia material): Processes highly acidic waste liquids (pH 0–2), flux ≥50 LMH.

Compliance: Compliant with EPA 40 CFR Part 112 (U.S. refinery wastewater discharge standards).

Filtration Process:

1. Acid wash wastewater → Neutralization + Flotation → Acid-resistant ceramic filtration → Reuse or discharge.

4. High-Temperature and High-Pressure Process Liquid Filtration

Application: Filtration for extreme conditions such as hydrocracking (temperature 400°C, pressure 15 MPa) and sulfur removal from heavy oils.

Technical Solution:

· Titanium Alloy Sintered Filter: Temperature resistance up to 450°C, filtration precision of 5–20 µm, hydrogen sulfide corrosion resistance.

· Duplex Steel Multi-Stage Filter: Pressure drop ≤0.2 MPa, ensures continuous operation of high-pressure systems.

Pain Point Resolution: Reduces catalyst bed fouling, extending operational cycle by 30%.

Filtration Process:

1. High-temperature process liquid → Titanium alloy filtration → Multi-stage filtration → Purified liquid for process continuation.

5. Cooling Water and Boiler Water Circulation

Application: Treatment of cooling water in ethylene units and boiler feedwater in steam boilers.

Technical Solution:

· Multi-Media Filter (Quartz sand + activated carbon): Removal of suspended solids (SS ≤10 mg/L).

· Electromagnetic Anti-Scaling System: Non-chemical method to control Ca²⁺ ≤50 ppm, reducing scale formation risk.

Energy and Water Saving Benefit: Recycling water efficiency increased from 60% to 85%, saving 500,000 m³ of water annually.

Filtration Process:

1. Cooling water → Multi-media filtration → Electromagnetic anti-scaling → Boiler or cooling system.

Other Applications in the Petrochemical Industry:

· Gas Filtration: Removal of dust and particulates from gases in refining processes, using HEPA filters or sintered metal filters.

· VOC (Volatile Organic Compound) Removal: Use of activated carbon filters for air and gas stream purification to meet environmental standards.