Distilled straight-run asphalt

It seems we only control the needle penetration depth; we don’t know what is done with it downstream

I would like to ask what parameters are used to control penetration? Furnace temperature, vacuum level, or something else?

Temperature, vacuum level, and feed flow rate can all affect penetration

The main factor is the furnace temperature; subsequently, the reflux in the tower is adjusted for fine-tuning. Later, the reduction-of-four process was modified, and within the unit, the amounts of reduced product and residue oil are controlled to make adjustments. This allows for deep penetration while still maintaining good control over the needle penetration depth.

I. Main operational parameters affecting asphalt quality: 1. Vacuum level: It is the basis for the operation of the vacuum distillation tower and has the greatest impact on the distillation efficiency. 2. Furnace exit temperature: It has a significant impact on yield, penetration, softening point, and composition. Therefore, the outlet temperature of the heating furnace must be strictly controlled. II. Main operating principles and requirements for asphalt production: 1. Low furnace temperature, high vacuum, low pressure drop. 2. Outlet temperature of the vacuum distillation tower: 370–390°C 3. Vacuum level: >98.5 KPa 4. Pressure drop across the tower: <1.5 KPa III. Main measures for adjusting the quality of asphalt: 1. Increase the vacuum level; control the temperature at the top of the tower properly; keep the bottom temperature at ≤360°C or lower; adjust the proportion of reflux used for heat extraction in each section of the tower. 2. Increase the amount of steam supplied at the bottom of the tower. 3. Adjust the amount of washing oil extracted. 4. Ensure deep drawing in the atmospheric pressure tower to maintain an appropriate load on the vacuum distillation tower. 5. Adjust the furnace outlet temperature.

What parameters are mainly controlled in the production of road asphalt through direct distillation? Also, when the properties of the oil change, which parameters are mainly used to reflect that? Firstly, reduced-pressure direct heating should be used (in very rare cases, normal-pressure direct heating is sufficient). The three key parameters—penetration, softening point, and ductility—must meet the requirements set by industry standards, the Ministry of Transport’s standards, and national standards. Furthermore, the wax content determines which standards the asphalt meets; only when all relevant tests show compliance can the asphalt be considered qualified. In principle, the raw material should have a low wax content. The main factors to consider are the relationship between penetration and softening point, the connection between ductility and wax content, as well as aging resistance. The density of the raw material is an indicator that can directly reflect changes in the quality of asphalt.