White spirit solvent extraction plant

Description

Technical Description: Kerosene-Derived White Spirit Production

Product: White Spirit (Hydrotreated Kerosene Fraction, Low Aroma Solvent)

Feedstock: Selectively refined kerosene fraction from crude oil distillation.

Objective: To produce a high-purity, low-odor, water-white aliphatic solvent meeting stringent specifications for odor, color, sulfur content, and aromaticity.

Core Production Process

1. Feedstock Selection: A specific kerosene fraction (boiling range typically ~180-230°C) is chosen for its inherent low aromatic and sulfur content relative to heavier fractions.

2. Hydrotreating (Core Transformation): The kerosene feed is processed under elevated temperature and pressure in the presence of hydrogen and a specialized catalyst (e.g., Co-Mo or Ni-Mo on alumina).

Key Reactions:

Desulfurization (HDS): Converts organic sulfur compounds (mercaptans, thiophenes) into hydrogen sulfide (H₂S), which is subsequently removed.

Denitrification (HDN): Removes nitrogen compounds.

Dearomatization (HDA): Saturates aromatic rings present in the feed, converting them into naphthenic or paraffinic compounds. This is critical for achieving low odor, high purity, and water-white color.

Olefin Saturation: Hydrogenates unsaturated hydrocarbons.

3. Product Separation & Fractionation: The hydrotreated effluent is cooled. Hydrogen sulfide, light gases, and excess hydrogen are separated (e.g., via stripper column, amine treatment for H₂S removal). The liquid product may undergo fractional distillation to precisely target the desired boiling range and volatility characteristics, removing lighter and heavier ends.

4. Finishing: Final treatment steps may include clay filtration or mild hydrogenation ("sweetening") to ensure exceptional color stability (typically water-white, ASTM D156/D1500/ISO 2049), complete odor removal, and removal of any trace polar compounds or catalyst fines.

5. Quality Control: Rigorous testing confirms key parameters:

Color: Water-white (Saybolt +30 / ASTM D156).

Odor: Extremely mild, characteristic aliphatic.

Sulfur Content: Very low (<10 ppm typical).

Aromatic Content: Very low (<0.1% typical).

Distillation Range: Tightly controlled for specific volatility.

Flash Point: Defined by the fraction (e.g., ~60-70°C).

Kauri-Butanol (KB) Value: Measures solvent power.

Key Characteristics of Final Product

High Purity: Predominantly iso-paraffins, n-paraffins, and naphthenes.

Low Odor & Toxicity: Resulting from near-complete dearomatization.

Water-White Color: Achieved through deep desulfurization and finishing.

Excellent Stability: Resists color degradation and oxidation.

Effective Aliphatic Solvent: Good solvency for oils, greases, waxes.

Low Surface Tension: Enhances wetting properties.

Low Electrical Conductivity: Suitable for electrical applications.

Primary Applications

Metalworking: Cold cleaning, degreasing, lubricant in rolling oils.

Paints & Coatings: Solvent for industrial maintenance paints, varnishes, enamels.

Agrochemicals: Carrier solvent in pesticide formulations.

Printing Inks: Solvent component.

Rubber & Polymer Processing: Diluent, cleaner.

Dry Cleaning: Spotting agent.

Consumer Products: Solvent in aerosols, polishes, cleaners.

Specialized Industrial Cleaning: Precision cleaning applications.

Advantages over Conventional Mineral Spirits

Superior odor profile.

Higher purity and color stability.

Lower toxicity and reduced environmental impact (low S, low aromatics).

Better performance in sensitive applications requiring low residue and stability.

FAQ

1. Q: What exactly is "White Spirit" made from kerosene?

A: It refers to a specific grade of highly refined, hydrotreated kerosene. This deep refining removes impurities, sulfur compounds, and aromatics, resulting in a clear, water-white, low-odor solvent oil, distinct from regular kerosene or mineral spirits.

2. Q: What are the key advantages of using hydrotreated kerosene as White Spirit?

A: Its main advantages are its very low sulfur content, low aromatic content (often <1%), minimal odor, high purity, excellent solvency for many oils and greases, and relatively low toxicity compared to many other solvents. It's also generally stable and has a high flash point.

3. Q: What are the typical applications for this type of White Spirit?

A: It's widely used as a solvent in applications requiring high purity and low odor/toxicity, such as:

Cleaning agents & degreasers (especially precision cleaning).

Carrier oils in pesticides, insecticides, and herbicides.

Solvent in printing inks and coatings.

Solvent for adhesives and sealants.

Extraction processes.

Lubricant and process oil additive blending.

4. Q: How should Kerosene-based White Spirit be stored?

A: Store it in tightly sealed, clean containers (preferably metal or approved plastic) away from heat, sparks, and open flame. Keep it in a cool, dry, well-ventilated area, protected from direct sunlight to prevent degradation and maintain its clear color.

5. Q: Does Kerosene-based White Spirit have a shelf life?

A: When stored properly (cool, dark, sealed), it typically has a very long shelf life (often years). However, prolonged storage, exposure to air, light, heat, or contaminants can lead to slight discoloration or the development of a mild odor over time. Check manufacturer specifications.

6. Q: Is it compatible with all materials?

A: While generally compatible with many metals and common plastics/rubbers, always test compatibility with specific materials (especially elastomers, seals, and certain plastics) before widespread use. Its solvency can affect some materials.

7. Q: What safety precautions are necessary when handling?

A: Although cleaner than regular kerosene, it's still a hydrocarbon solvent. Use with adequate ventilation. Avoid prolonged skin contact (use gloves) and eye contact (use safety glasses). It is flammable – keep away from ignition sources. Refer to the specific product's Safety Data Sheet (SDS) for detailed handling, PPE, and first aid information.

8. Q: Why choose hydrotreated kerosene over other solvents like mineral spirits or acetone?

A: It offers a unique balance: superior purity, very low odor, low toxicity, and good solvency for oils/greases compared to mineral spirits (which have higher aromatics and stronger odor). It's less volatile and evaporates slower than acetone, making it better for certain cleaning or carrier applications. It provides a cleaner, more refined alternative where those properties are critical.