Bitumen emulsions are produced by special continuous or batch units, usually based on a colloid mill.
First, the solution of emulsifier and bitumen passes through a mill, where emulsifying occurs. Production of cationic bitumen emulsions require a soap solution. It contains water, acid and emulsifier mixed together in ratio ensuring the proper acidity. A special solvent is often added to bitumen emulsions, usually kerosene, diesel or white spirit.
To eliminate the risk of local overheating, the temperature difference of bitumen and emulsifier solution must be minimized. However, bitumen temperautre should be sufficient for pumping.
Batch type plants
The identifying feature of batch plants is production and dilution of emulsifier solution in a dosing tank. If solvent must be mixed with bitumen, an additional dosing tank for bitumen can be be used; solvent can be injected continuously.
High volume components like bitumen or water can be measured by level marks on a tank. For fewer amounts, a more accurate measuring unit is used.
The main difference of continuous operation plants is that there aren’t any dosing tanks. Bitumen and emulsifier solution are injected directly from supply tanks.
Emulsifier solvent is prepared automatically according to input formula by injection of emulsifier, acid and stabilizer into a water supply line. Before the water enters the colloid mill, emulsifier and acid must react chemically.
Water is heated to the required temperature by a continuous heater. Emulsifiers must be easily dispersible in water. This is required for faster reaction with acid. Dosing of acid is controlled by a sensor fixed on the water line just before the colloid mill. Bitumen and solvent (if required) are supplied to the colloid mill is continuously as well.
Continuous operation plant works while the materials are available and there is free space for product output.