Skewers
CHUANYE
String liquid causes
1) Due to improper selection of plate material, resulting in plate corrosion cracks or perforations.
2) Operating conditions do not meet the design requirements.
3) Residual stress after the plate cold stamping and forming and assembly of the clamping size is too small to cause stress corrosion.
Corrosion.
4) There is a slight leakage at the leakage slot of the plate, resulting in the concentration of harmful substances in the medium (e.g., C1) corrode the plate, forming a string of liquid.
Example.
An aluminium company sulfuric acid system in a plate sheet material for 254 SMo AM10 plate heat exchanger, in the operation of 5 months after the cooling water side of the carbon steel receiver corrosion leakage, acid leakage to the cooling water side.
Inspection found serious corrosion and cracking at the acid inlet of the plate sheet and in the infusion area. On-site analysis revealed that process parameters such as system operating temperature, flow rate and concentration were beyond design conditions, and the use temperature was far beyond the applicable range of the material.
The plate heat exchanger using saturated steam as the primary side heat source is prone to plate corrosion during operation, resulting in product stringing.
This is due to the high temperature of the steam, equipment operation is easily caused by rubber gasket failure at high temperatures, causing steam leakage and rapid condensation in the second sealing area. With the continuous leakage, condensation residual liquid more and more, the local formation of cl quality concentration of high areas, to destroy the surface of the plate passivation layer of corrosion conditions. At the same time, due to this region of the plate cold stamping the formation of the internal stress is greater, in the case of surface passivation layer is destroyed, the role of internal stress leads to the occurrence of stress corrosion.
String liquid treatment method
1) Replace the cracked or perforated plates, and find the cracked plates on site by light transmission method.
2) Adjust the operating parameters to achieve the design conditions.
3) Heat exchanger repair and assembly of the clamping size should meet the requirements, not the smaller the better.
4) Plate material reasonable matching.
The above is the plate heat exchanger string of liquid causes and treatment methods, and in order to later products can continue to operate stably, but also must be periodically cleaned and inspected the plate heat exchanger components, to avoid the occurrence of string of liquid accidents.
