bitumen polymerization

Alexandria Engineering Industries designs and manufactures advanced bitumen polymerization production lines for the manufacturing of Polymer-Modified Bitumen (PMB)—a high-performance binder used in demanding road construction, airport runways, bridge decks, and waterproofing applications.

These systems integrate controlled polymer blending, swelling, and degradation into hot bitumen to significantly enhance elasticity, temperature susceptibility, aging resistance, and durability—meeting international standards such as EN 14023, ASTM D6114, and AASHTO M320.

Key Process Stages

1. Bitumen Melting & Pre-Heating

• Solid or drummed bitumen is melted in a jacketed storage tank (140–180°C) using thermal oil or steam heating.
• Agitators ensure homogeneity and prevent localized overheating.

2. Polymer Dosing System

• Precise feeding of thermoplastic polymers (e.g., SBS – Styrene-Butadiene-Styrene, SBR – Styrene-Butadiene Rubber, EVA – Ethylene Vinyl Acetate, or crumb rubber) via:
  • Screw feeders (for pellets/granules)
  • Pneumatic conveyors (for fine powders)
  • Weighing hoppers with loss-in-weight control

3. High-Shear Mixing & Swelling Reactor

• Primary reactor equipped with high-torque agitator and high-shear mixer (rotor-stator or disperser).
• Controlled temperature (170–190°C) and mixing time allow polymers to swell and disperse uniformly in the bitumen matrix.

4. Stabilization & Degradation Control

• Addition of stabilizing additives (e.g., sulfur, phenolic resins) to prevent polymer-bitumen separation.
• Optional devolatilization under mild vacuum to remove moisture or volatiles.

5. Maturation & Homogenization

• Secondary holding tank with slow-speed agitator for 30–90 minutes to ensure complete reaction and homogeneity.
• Temperature maintained to prevent gelation or settling.

6. Quality Control & Filtration (Optional)

• Inline viscosity monitoring and sampling ports for lab testing.
• Filter unit (e.g., 100–200 micron) to remove undissolved polymer lumps or impurities.

7. Storage & Loading

• Insulated, agitated storage tanks with nitrogen blanketing (optional) to minimize oxidation.
• Pumping system for transfer to tankers, drums, or downstream emulsion plants.

Key Features

✅ High Polymer Loading: Supports 3–15% polymer content (standard: 4–6% SBS).
✅ Full Automation: PLC + HMI with recipe management for different PMB grades (e.g., PMB 45/80-65, PMB 60/100-70).
✅ Energy Efficient: Thermal oil heating with insulation and heat recovery options.
✅ Robust Construction: Carbon steel with high-temp coating or stainless steel for critical zones.
✅ Scalable Capacity: From 1 to 20 tons/hour (batch or semi-continuous).
✅ Compliance Ready: Produces PMB meeting penetration, softening point, elasticity (>60%), and storage stability requirements.