1. Two kinds of media inter-string (Internal Leakage)
Causes
① Heat Exchanger tube corrosion perforation, cracking.
② Heat Exchanger tube and tube plate expansion port (weld) cracking.
③ Floating head Heat Exchanger - Floating head flange seal leakage.
Processing Methods
① Replace or plug the leaky heat exchanger tube.
② Heat Exchanger tube and tube plate re-expansion (welding) or plugging.
③ Tighten the bolts or replace the sealing gasket.
2. Seal leakage at Flange
Causes
① Insufficient pressure-bearing, corrosion and deterioration of the gasket.
② Insufficient bolt strength, loosening or corrosion.
③ Insufficient rigidity of the flange and sealing surface defects.
④ Flange is not flat or misaligned, gasket quality is not good.
Treatment Method
① Tighten the bolt and replace the gasket.
② Upgrade the bolt material, tighten the bolt or replace the bolt.
③ Replace the flange or deal with the defect.
④ Reassemble or replace the flange and replace the gasket.
3. Poor heat transfer
Causes
①Heat exchange tube scaling.
②Bad water quality, oil and microorganisms.
③Separator short circuit
Treatment Method
①Chemical cleaning or jet cleaning of scale.
②Strengthen the filtration and purification medium and strengthen the water quality management.
③Replace pipe box gasket or replace the bulkhead.
4. Resistance drop exceeds the allowable value
Causes
Fouling inside the shell, inside and outside the tube
Treatment Method
Clean the scale with jet or chemical
5. Severe vibration
Causes
① Resonance caused by medium frequency.
② Resonance caused by external pipe vibration.
Treatment Method
①Change the flow rate or change the inherent frequency of the pipe bundle.
②Strengthen the pipe to reduce the vibration.
6. Tube bundle failure
1-> Tube bundle corrosion, wear caused by tube bundle leakage or tube bundle scaling caused by blockage failure
Cooling water contains iron, calcium, magnesium and other metal ions and anions and organic matter, active ions will make the cooling water corrosive enhance, the presence of metal ions cause hydrogen or oxygen depolarization reaction thus leading to tube bundle corrosion. At the same time, because the cooling water contains Ca2+ and Mg2+ ions, it is easy to scale and block the pipe bundle under high temperature for a long time.
In order to improve the heat transfer effect and prevent the tube bundle from corrosion or blockage, the following methods are adopted.
(1) Add scale inhibitors to the cooling water and clean it regularly.
For example, the cooling water of gas cooler adopts ion electrostatic processor or adds scale and corrosion inhibitor and algaecide to remove the dirt and reduce the hardness of cooling water, so as to reduce the degree of tube bundle fouling.
(2) Keep the fluid flow rate in the tube stable.
If the flow rate increases, the thermal conductivity becomes larger, but the wear and tear will also increase accordingly. Minsheng Coal Chemical has reformed the groundwater pump with frequency conversion, which makes the pressure of groundwater network more stable and improves the heat exchange effect of heat exchanger and reduces the corrosion of tube bundle.
(3) Choose corrosion-resistant materials (stainless steel, copper) or increase the wall thickness of the tube bundle.
(4) When the end of the tube wears out, you can access synthetic resin and other protective tube bundles in the inlet 200mm length.
2-> Vibration caused by the failure
Causes of vibration include: Vibration of the tube bundle caused by the vibration of the pump and compressor; pulsation generated by rotating machinery. Flow into the tube bundle of high-speed fluid (high-pressure water, steam, etc.) on the impact of the tube bundle.
Reduce the vibration of the tube bundle often use the following methods:
(1) Minimize the number of openings and stops.
(2) At the entrance of the fluid, install adjustment grooves to reduce the vibration of the tube bundle.
(3) Reduce the distance between baffles to reduce the amplitude of the bundle.
(4) Minimize the aperture of the tube bundle through the baffle.
