Specialized Emulsified Asphalt Equipment for High-Viscosity Asphalt: Upgraded Preheating System (Temperature Resistance ≥180℃), Enhanced Shearing Colloid Mill (Speed ≥3000r/min), and Anti-Clogging Feeding Design

High-viscosity asphalt (with a penetration grade of ≤40 dmm at 25℃, such as SBS-modified asphalt or heavy-duty road asphalt) poses unique challenges to emulsification: its high initial viscosity makes it difficult to flow and mix with soap solution, easy to cause feeding blockages, and requires stronger shearing force to break asphalt particles into micron-sized droplets (≤5μm) for stable emulsion formation. Conventional emulsified asphalt equipment, designed for low-to-medium viscosity asphalt, often fails to meet these demands—resulting in uneven emulsification, low emulsion stability, or frequent equipment downtime. This article focuses on the three core upgrade directions of specialized equipment for high-viscosity asphalt: upgraded preheating system, enhanced shearing colloid mill, and anti-clogging feeding design. It dissects their technical principles, performance indicators, and application values to provide a reference for equipment selection and efficiency improvement in high-viscosity asphalt emulsification projects.

1. Upgraded Preheating System (Temperature Resistance ≥180℃): Reducing Viscosity to Enable Smooth Flow

The core challenge of high-viscosity asphalt emulsification lies in its extremely high viscosity at room temperature (often exceeding 10,000 cP), which prevents it from being pumped or mixed with soap solution. The preheating system’s role is to heat the asphalt to a "flowable viscosity range" (200-300 cP) while ensuring stable temperature control—avoiding asphalt aging due to overheating or insufficient viscosity reduction due to underheating. Conventional preheating systems (with a maximum temperature of 150℃) are ineffective for high-viscosity asphalt, requiring targeted upgrades.

1.1 Technical Upgrades for Temperature Resistance and Uniform Heating

To achieve reliable preheating of high-viscosity asphalt, the system needs upgrades in heating medium, heater structure, and temperature control precision:

High-Temperature Heating Medium: Replace conventional hot water (maximum temperature ≤100℃) with thermal oil (such as mineral oil with a flash point ≥280℃) as the heating medium. Thermal oil can stably operate at 180-220℃ without vaporization, ensuring the asphalt is heated to the required temperature. The thermal oil circulation system is equipped with a dual-heating source (electric heater + gas burner) to avoid heating interruptions caused by single-source failures.

Multi-Zone Heat Transfer Structure: The asphalt preheating tank adopts a "jacket + coil" composite heating design. The outer jacket provides overall heating to the tank body, while the internal coil (distributed in a spiral pattern) extends into the asphalt to heat the core area—solving the problem of uneven temperature distribution (e.g., overheating of the tank wall and underheating of the internal asphalt) in conventional single-jacket tanks. The tank is also insulated with 100mm-thick rock wool (thermal conductivity ≤0.04 W/(m·K)) to reduce heat loss, ensuring the temperature drop rate is ≤5℃/h during standby.

Dual-Layer Temperature Monitoring: Install two sets of PT100 platinum resistance thermometers (measurement range -50℃~300℃, accuracy ±0.5℃) in the preheating tank: one at the tank wall (monitoring the heating surface temperature to prevent local overheating) and one at the asphalt outlet (monitoring the actual temperature of the pumped asphalt). The temperature control system (equipped with a PID controller) adjusts the heating power in real time based on the outlet temperature—maintaining the asphalt temperature at 160-180℃ (the optimal range for high-viscosity asphalt flow) with a fluctuation range of ≤±3℃.

1.2 Anti-Aging Protection for Asphalt During Preheating

High-viscosity asphalt is prone to aging (oxidation and component decomposition) when heated above 190℃, which reduces the emulsion’s final performance. The upgraded preheating system incorporates two anti-aging measures:

Over-Temperature Alarm and Shutdown: Set an over-temperature threshold of 190℃. If the asphalt temperature exceeds this value, the system immediately triggers an audible-visual alarm, cuts off the heating source, and starts a cooling fan for the thermal oil system—preventing asphalt aging.

Inert Gas Sealing: Fill the top of the preheating tank with nitrogen (purity ≥99.9%) to isolate the asphalt from air. This reduces oxidative aging during the preheating process, especially for long-term storage of heated asphalt (e.g., 8-hour standby). Tests show that nitrogen-sealed asphalt has a softening point increase of ≤1℃ after 8 hours of preheating, compared to 3-4℃ for air-exposed asphalt.

1.3 Application Value: Ensuring Continuous and Stable Feeding

In a highway maintenance project using SBS-modified high-viscosity asphalt (penetration grade 30/40), the upgraded preheating system achieved significant results:

The asphalt viscosity was reduced from 15,000 cP (room temperature) to 250 cP (170℃), enabling smooth pumping to the colloid mill without flow blockages.

The temperature fluctuation during 12 hours of continuous operation was controlled within ±2℃, avoiding emulsification instability caused by temperature variations.

Asphalt aging was minimized, with the emulsified asphalt’s storage stability (5-day separation rate) ≤0.3%—meeting the requirements of ASTM D244.