Abstract: The heat transfer oil heating system is a core component of asphalt tank operation, and its energy efficiency directly affects the overall operation cost and environmental performance of asphalt storage and heating projects. This paper focuses on the energy consumption pain points of traditional asphalt tank heat transfer oil heating systems, and systematically expounds the optimization design and retrofit tips of the system from the aspects of heating system matching, insulation structure upgrading, intelligent control application and daily operation management, aiming to provide practical and feasible energy-saving schemes for relevant enterprises.

1. Introduction

Asphalt tanks are widely used in road construction, asphalt production and other fields, and the heating link is essential to ensure the fluidity of asphalt. The heat transfer oil heating system, with its advantages of uniform heating temperature and stable heat supply, has become the mainstream heating method of asphalt tanks. However, in the long-term operation process, problems such as unreasonable system matching, poor insulation effect and backward control mode often lead to high energy consumption of the heating system, which increases the operation burden of enterprises. Therefore, it is of great practical significance to carry out energy efficiency optimization and retrofit work for the heat transfer oil heating system of asphalt tanks.

2. Energy Consumption Analysis of Traditional Heat Transfer Oil Heating Systems

2.1 System Matching DefectsIn the design stage of many traditional asphalt tank projects, the heat transfer oil boiler and the heating pipeline network are not matched with the actual asphalt heating demand. The boiler output is too large or too small, which will lead to low heat utilization rate. For example, when the boiler output exceeds the actual demand, a large amount of heat will be wasted through the overflow pipeline; when the output is insufficient, it will be in a long-term overload operation state, which will not only increase energy consumption but also shorten the service life of the equipment.

2.2 Insufficient Insulation PerformanceThe insulation effect of the heat transfer oil pipeline and asphalt tank body is an important factor affecting energy consumption. Traditional insulation materials such as glass wool have problems such as poor aging resistance and easy moisture absorption. After long-term use, the insulation performance will decline sharply, resulting in a large amount of heat loss in the process of heat transfer. In addition, the poor sealing of pipeline joints and tank body connections will also cause heat leakage.

2.3 Backward Control ModeMost traditional heating systems adopt manual control or simple on-off control mode, which cannot adjust the heat supply according to the real-time temperature change of asphalt. This will lead to the phenomenon of overheating or insufficient heating of asphalt. Overheating will not only waste energy but also affect the performance of asphalt; insufficient heating will affect the fluidity of asphalt and normal construction.

3. Optimization Design Tips for Heat Transfer Oil Heating Systems

3.1 Demand-oriented System MatchingBefore the design of the heating system, it is necessary to accurately calculate the heating demand according to the parameters such as the volume of the asphalt tank, the initial temperature of asphalt and the required heating temperature. On this basis, select the heat transfer oil boiler with appropriate output power, and design the pipeline network with reasonable diameter and layout. Adopt the mode of "one tank one boiler" or "multiple tanks sharing one boiler" according to the actual production scale to improve the matching degree of the system.

3.2 High-performance Insulation Scheme DesignFor the asphalt tank body, select the composite insulation material with good insulation performance, aging resistance and waterproof performance, such as polyurethane rigid foam + aluminum alloy protective layer, to improve the insulation effect of the tank body. For the heat transfer oil pipeline, use the pre-insulated pipe with closed structure, and strengthen the insulation treatment of the pipeline joints and valves. At the same time, set up a heat insulation layer at the connection between the boiler and the pipeline to reduce heat loss at the key parts.

3.3 Application of Intelligent Temperature Control SystemInstall temperature sensors at different positions of the asphalt tank and the heat transfer oil pipeline to collect real-time temperature data. Connect the sensor with the intelligent control system to realize the automatic adjustment of the boiler output and the flow rate of the heat transfer oil. When the asphalt temperature reaches the set value, the system automatically reduces the boiler output or stops heating; when the temperature drops, it automatically starts the heating system, so as to realize the precise control of the heating process and reduce unnecessary energy consumption.

4. Retrofit Tips for Existing Heat Transfer Oil Heating Systems

4.1 Retrofit of Heat Transfer Oil BoilerFor the boiler with low thermal efficiency in operation, the heat exchange surface can be retrofitted, such as adding fins on the heat exchange pipe to increase the heat exchange area. At the same time, clean the scale and carbon deposits inside the boiler regularly to improve the heat transfer efficiency of the boiler. For the boilers with serious energy consumption, it is recommended to replace them with high-efficiency heat transfer oil boilers with energy-saving certification.

4.2 Upgrading of Insulation StructureFor the asphalt tank and pipeline with aging insulation layer, remove the old insulation material in time and replace it with a new type of composite insulation material. Strengthen the sealing treatment of the pipeline joints and tank body manholes, and use high-temperature resistant sealing materials to prevent heat leakage. In addition, a heat insulation cover can be added for the key parts such as the heat transfer oil pump and valve to further reduce heat loss.

4.3 Transformation of Control SystemTransform the traditional manual control system into an automatic control system based on PLC or DCS. Add frequency conversion devices to the heat transfer oil pump to adjust the pump speed according to the actual demand and reduce the energy consumption of the pump. At the same time, install an energy consumption monitoring system to monitor the energy consumption of the heating system in real time, and provide data support for subsequent energy efficiency optimization.

5. Daily Operation Management for Energy Saving

5.1 Regular Maintenance of EquipmentFormulate a regular maintenance plan for the heat transfer oil heating system. Regularly check the tightness of the pipeline, the operation status of the boiler and the performance of the insulation layer. Replace the aging heat transfer oil in time to avoid the decrease of heat transfer efficiency caused by the deterioration of the oil quality. Clean the heat exchange surface of the boiler regularly to remove scale and carbon deposits.

5.2 Standardized Operation ProcessFormulate standardized operation procedures for the operators, and strictly control the heating temperature and time of asphalt. Avoid the phenomenon of long-term idle operation of the heating system. When multiple asphalt tanks need to be heated, reasonably arrange the heating sequence according to the production demand to realize the peak shifting and valley filling of energy consumption.

6. Conclusion

The energy efficiency optimization and retrofit of the asphalt tank heat transfer oil heating system is a systematic project involving system design, equipment retrofit and operation management. By adopting demand-oriented system matching, high-performance insulation scheme, intelligent control system and standardized operation management, the energy consumption of the heating system can be effectively reduced, the operation cost of enterprises can be saved, and the environmental protection level of the project can be improved. With the continuous development of energy-saving technology, the energy efficiency potential of the asphalt tank heat transfer oil heating system will be further explored, which will contribute to the green development of the asphalt industry.