Physical method:
1. Mechanical cleaning method: cleaner and scraper cleaning method, drill pipe cleaning method, shot peening cleaning method.
2. Water cleaning method: low pressure water cleaning (the pressure of low pressure cleaning is 196-686kpa, about 2-7kgf / cm2, equal to 0.2-0.7mpa).
3. Cleaning of high pressure water jet equipment: the pressure of high pressure cleaning is 4900 kPa, about 50 kgf / cm2, equal to 5 MPa. This method is also called high-pressure water jet method, high-pressure cleaning machine.
Electronic method:
The principle is: using high frequency electric field to change the molecular structure of water to prevent and remove scale. When water passes through the high frequency electric field, its molecular physical structure changes, and the original association chain like large component wyt is formed_ Dsry is broken into a single water molecule, the positive and negative ions of salt in water are surrounded by a single water molecule, the movement speed is reduced, the number of effective collisions is reduced, and the electrostatic attraction is reduced, so it is unable to structure on the heated wall tube surface, so as to achieve the purpose of anti scaling. At the same time, due to the increase of the dipole moment of water molecules, the absorption ability of water molecules with the positive and negative ions (scale molecules) of salt increases, so that the scale on the heating surface or pipe wall becomes soft and easy to fall off, resulting in the effect of scale removal.
Electrostatic method:
Electrostatic antiscaling and descaling, like electronic descaling, also achieve the purpose of antiscaling and descaling by changing the state of water molecules. But the latter uses the action of electrostatic field instead of electron. The mechanism is that water molecules have polarity (also known as dipoles). When water dipoles pass through the electrostatic field, each water dipoles will be arranged in positive and negative order. If there are dissolved salts in water, the positive and negative ions will be surrounded by water dipoles and arranged in the group of water dipoles in positive and negative order, so they can't move by themselves, so they can't get close to the pipe (vessel) wall, and then deposit on the pipe (vessel) wall to form scale. At the same time, the oxygen released from the water can produce a very thin oxide layer on the pipe wall, which can prevent the corrosion of the pipe wall.
Chemical method:
Chemical agents are used to remove the surface pollution or covering layer by chemical reaction with it, such as pickling and alkali washing of scale layer. In order to protect the substrate from corrosion in chemical cleaning or control the corrosion rate within the allowable range, an appropriate amount of corrosion inhibitor and additives for activation, penetration and wetting are usually added into the chemical cleaning solution. Methods: soaking method, circulation method and cleaning method in operation are also called non-stop chemical cleaning method.