Asphalt tanks rely on circulating heat medium to maintain asphalt fluidity; uneven flow distribution easily leads to local overheating coking and low-temperature solidification in dead zones. Heat medium flow control technology achieves balanced temperature distribution inside the tank by optimizing diversion structure, pipeline layout and dynamic regulation strategy, improving heating efficiency while reducing energy consumption and asphalt deterioration risks.

The root causes of temperature imbalance originate from unreasonable flow field distribution of heat medium. Single-inlet and single-outlet layout causes short-circuit circulation of hot medium; the heating coil near the inlet bears excessive heat load while the remote area lacks sufficient heat supply. Excessive flow velocity induces pipeline vibration and coil weld stress concentration; insufficient flow leads to slow heat transfer and large temperature difference between the tank bottom and upper layer. In addition, improper branch pipe valve matching, pipeline scaling and unsmooth medium circulation will further amplify temperature deviation, triggering successive asphalt coking and solidification defects.

Optimize diversion structure and coil layout to reconstruct internal flow field. Adopt segmented parallel coil layout with independent branch pipes for the tank bottom and side walls; install diversion baffles in the medium circulation chamber to guide uniform flow and avoid direct short-circuit of hot medium. Set flow equalizing holes at intervals on the coil support structure to reduce local turbulence. The inlet and outlet are arranged diagonally to form a complete circulating flow path inside the tank, narrowing the overall temperature difference. For large-volume asphalt tanks, multi-group independent circulation loops are adopted to realize zoned temperature control of different areas of the tank body.

Configure multi-stage flow regulation system for dynamic matching of working conditions. Install electric regulating valves, flow sensors and temperature acquisition modules on each circulation branch; the PLC system adjusts the opening of the valve according to real-time temperature feedback of each area to stabilize the medium flow rate of each loop. Set flow upper and lower limit protection to prevent coil thermal shock caused by sudden flow surge or insufficient heat supply due to flow interruption. Equip filters and blowdown ports at the medium inlet to remove impurities and avoid pipeline scaling blocking flow passages.

Optimize pipeline design and operation parameters to stabilize circulation performance. Control the flow velocity of heat medium pipeline within 1.2～2.0m/s; excessively high velocity causes pipeline vibration and noise, while excessively low velocity leads to impurity deposition and pipeline fouling. Keep the pipeline slope reasonable to facilitate exhaust and prevent air lock from blocking circulation. Regularly inspect the heat medium pump and heat exchanger to guarantee stable pressure difference of the circulation system. Adjust the flow strategy according to seasonal ambient temperature: increase flow in cold winter and appropriately reduce flow in hot summer to achieve energy-saving operation.

Carry out thermal balance verification test after equipment commissioning. Arrange multiple temperature measuring points at the tank bottom, middle and upper layers to monitor temperature changes under continuous heating. Simulate low-load and high-load operation to expose hidden flow dead zones. Adjust coil spacing, branch flow distribution and valve parameters according to test data until the temperature difference inside the tank is controlled within the allowable range. Form standardized flow regulation curves for different asphalt storage capacities.

Cooperate with preventive maintenance to sustain long-term stable flow control. Regularly clean pipeline and coil fouling, inspect the sealing performance of valves and sensors, and replace aging components in advance. Establish operation logs to record medium flow, temperature distribution and equipment operating parameters. Once local temperature drift occurs, quickly judge whether the fault lies in flow regulation failure or pipeline blockage, and implement targeted troubleshooting.

Heat medium flow control technology integrates flow field optimization, automatic regulation and standardized maintenance to realize balanced heating of asphalt tanks. The technology effectively suppresses local asphalt coking and low-temperature solidification, improves thermal energy utilization efficiency, and is widely applicable to fixed asphalt storage tanks and mobile asphalt heating tanks for road engineering.