Analysis of heat exchanger fouling reasons and selection of industrial cleaning methods
Causes of heat exchanger scaling
Because most commonly used heat exchanger heat exchanger based on (1) water for heating medium in heating system, because of some salts in the temperature and precipitation at high concentration in the water, attached to the surface of heat exchange tube, the formation of scale, with the increase of using time and frequency of fouling layer gradually thickening, hardening, tightly attached on the surface of heat exchange tube;
(2) Like scale, the fluid on the other side of the heat exchanger may have non-scale solid precipitates due to the nature of the substance itself. If it is not treated for a long time, it will accumulate more and more on the surface of the heat exchange tube.
(3) when the mechanical impurities and organic matter contained in the fluid are more and the flow rate of the fluid is small, some mechanical impurities or organic matter will also be deposited in the heat exchanger, forming loose, porous or colloidal dirt.
Cleaning method
Chemical cleaning
Is through the chemical cleaning fluid to produce a chemical reaction, so that the heat exchanger heat transfer tube surface scale and other sediments dissolve, fall off or peel. Chemical cleaning does not need to open the heat exchanger, simplifying the cleaning process, but also reduce the degree of labor cleaning. The disadvantage is that the chemical cleaning fluid is not selected at the right time, it will corrode the substrate of the cleaning material and cause losses.
Chemical cleaning method
? circulation method: with pump forced cleaning fluid circulation, cleaning.
? Impregnation method: fill the cleaning solution with the equipment and let it sit for a certain time.
? Surge method: the cleaning liquid is filled with equipment, and part of the cleaning liquid is discharged from the bottom at certain intervals, and then the discharged liquid is installed back into the equipment to achieve the purpose of stirring and cleaning.
The physical cleaning
With the help of a variety of mechanical force and energy to make the dirt crushing, separation and peeling away from the surface of the object, so as to achieve the effect of cleaning. Physical cleaning methods have one thing in common: high efficiency, no corrosion, safety, environmental protection. Its disadvantage is that when cleaning the complex structure of the equipment inside the force sometimes can not reach all parts of the uniform and appear "dead Angle".
Common methods include ultrasonic descaling, PIG pigging technology, electric field descaling technology, etc.
