Anti-scaling treatment of air heat exchanger
After the heat exchanger of the air heat exchanger of Changzhou Yaoneng Machinery Co., Ltd. runs for a certain period of time, a layer of white scale adheres to the inner and outer walls of the heat exchanger. The main reason for the formation of scale is that the water contains less soluble calcium and magnesium. Salts, which have common characteristics, whose solubility decreases with increasing water temperature and become difficult salts. The presence of such salts has the following consequences for heat exchangers:
1. The thermal conductivity of scale is very poor. It is 30 to 50 times smaller than the thermal conductivity of steel. If there is scale, the heat transfer surface will be deteriorated. Therefore, the heat transfer surface cannot reach the ideal temperature drop. According to the relevant information, after the experiment, 1mm thick scale will be produced, and the heat exchanger will reduce the efficiency by about 10%.
2. The scale is attached to the heat transfer surface, which is difficult to remove and increases the maintenance cost. It not only consumes manpower and material resources, but also damages the heated surface and reduces the life of the heat exchanger.
3. After the scale is generated, the flow cross section inside and outside the heat transfer surface will be reduced, and the flow resistance of the circulating water inside and outside the heat transfer surface will be increased. When the flow section is small, or even completely blocked, the heat exchanger will not operate normally.
In order to prevent the above consequences, the current design unit or operating unit often uses methods such as dosing and softening treatment, magnetization, ion bar anti-scaling treatment, and sodium ion exchange treatment. In order to facilitate further understanding of these softening treatment methods, the principles, formulations and operation methods of these treatment methods are respectively introduced below.
one. Dosing and softening treatment
The method of softening and adding medicine has the characteristics of simple method, high efficiency, good economy and no special water-making equipment, and is a practical and anti-scale water treatment method. According to the different methods of dosing, there are two kinds of calibrator treatment and anti-scaling treatment.
two. Magnetized anti-scaling treatment
The principle of magnetization anti-scaling treatment is to use the polarity of water molecules, that is, the water molecules are covalently combined. The single molecules of water are polymerized into a bimolecular association (H2O) 2 or multi-molecular association by the action of polarity and hydrogen bonding. (H2O)n. When the water flows through a high-intensity magnetic field, the multi-molecular association and the ionic magnetic field in the water, the original multi-ionic association of the multi-ion is broken up into a single or short-bond association, which is perpendicular to the speed. The magnetic field lines of the external magnetic field are cut to generate an induced current. Therefore, each ion establishes a new magnetic field in the same direction as the external magnetic field, and adjacent ion molecules with polarity are sequentially compressed and attracted to each other, resulting in a change in crystallization conditions, and the formed crystals are slack and resistant. It has poor pressure and tensile strength, and is very brittle. Its adhesion and adhesion are also weak. They are not easy to adhere to the heated surface to form scale.