Before the tank is emptied, when the asphalt is extracted the next time, the asphalt depth in the bitumen storage tank shall not be less than 35cm. These asphalt shall be heated to more than 120 ℃ (the modified asphalt is 170 ℃) and pumped at one time, otherwise more asphalt will remain at the bottom of the tank.

If the depth of remaining asphalt is less than 35cm before emptying the asphalt in the tank, the following methods shall be followed according to different conditions:

1. When the boiler and external pipelines on site have not been removed, check the asphalt level position, open the low-level manhole cover for observation. If the asphalt level surface is higher than the upper surface of the heating pipe (the observation position of the outer discharge pipe of the tank structure in the tank), continue to heat the asphalt to more than 120 ℃ (the modified asphalt is 170 ℃), and then empty the asphalt; If the asphalt liquid level surface is lower than the upper surface height of the heating pipe (the observation position of the tank structure in the tank), and there is available asphalt in other bitumen storage tanks on site, the asphalt in other bitumen storage tanks can be heated to more than 120 ℃ (the modified asphalt is 170 ℃) and injected into this bitumen storage tank, Until the asphalt level in the bitumen storage tank is more than 5cm higher than the upper surface of the heating pipe (the observation position of the tank structure in the tank), then heat it together with the remaining asphalt in the bitumen storage tank to more than 120 ℃ (the modified asphalt is 170 ℃), and empty the bitumen storage tank.

2. If the site does not meet the above conditions and the above operations cannot be realized, manual cleaning is required. If the temperature on site is very high during manual cleaning and the asphalt surface is in a sticky state and difficult to operate, inject cold water into the bitumen storage tank until it does not cross the asphalt liquid level, add water according to the usual washing amount of washing powder, stir and melt, then use special tools such as spade and shovel to divide and clean the asphalt, put the massive asphalt into a bag and take it out of the tank through the low-level manhole.

3. If the above conditions are not met, a professional asphalt cleaning company can be entrusted to the site for professional and rapid cleaning. For the above asphalt cleaning methods, professionals are required to follow the safe operation procedures in the whole process, and operate carefully under the condition of ensuring safety.