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Evaporator Some Common Fault Handling Methods
- Jun 15, 2017 -

Evaporator some common fault handling methods

Leakage - causes

① clamping size is not in place, uneven size (size deviation should not be greater than 3mm) or clamping bolts loose. ② part of the gasket from the sealing groove, the main seal sealing surface dirt, gasket damage or evaporator gasket aging. ③ plate deformation, assembly dislocation caused by running pad. ④ cracks in the plate seal groove or two sealed area. Example: A number of heat stations in Beijing, Qinghai and Xinjiang use saturated steam as a primary heat source. Due to the high steam temperature, the rubber gasket fails at high temperatures due to the unstable system at the beginning of the equipment operation. Steam leakage.

Approach

① In the non-pressure state, according to the manufacturer to provide the clamping size of the re-clamping equipment, size should be uniform, compression size deviation should not be greater than ± 0.2N (mm) (N for the total number of plates), two The parallelism between the plates should be kept within 2 mm. ② in the leaks on the site to do a good job, and then disassemble the evaporator one by one troubleshooting, re-assembly or replacement of gaskets and plates. ③ will open the evaporator disintegration, the deformation of the plate parts to repair or replace the plate. In the absence of spare parts when the plate can be temporarily removed after the re-assembly use. ④ When assembling the disassembled plate, clean the board to prevent dirt from adhering to the gasket sealing surface.

 

String - causes

① due to improper selection of plate plate corrosion caused by cracks or perforation. ② operating conditions do not meet the design requirements. ③ plate cold stamping after the residual stress and assembly in the clamping size is too small to cause stress corrosion. ④ sheet leakage at the leak there is a slight leakage, resulting in the formation of harmful substances in the media corrosive plate, forming a string of liquid. Example: An aluminum industry in the sulfuric acid system in a plate material 254 SMo BR03 evaporator, in the run after 5 months after the cooling side of the carbon steel pipe corrosion leakage, acid leakage to the cooling water side. Inspection found that the plate acid inlet and diversion area has serious corrosion and cracking phenomenon. Field analysis found that the system operating temperature, flow and concentration of process parameters are beyond the design conditions, the use of temperature far beyond the scope of application of the material. The use of saturated steam as a primary heat source of the evaporator in the course of the operation of the plate prone to corrosion, resulting in product string. This is due to the high temperature of the steam, the equipment is very easy to cause the operation of the rubber gasket at high temperature failure, causing steam leakage and rapid sealing in the two sealed area. With the continuous leakage, the condensate residue more and more, the local formation of cl mass concentration of high areas, to destroy the surface of the plate passivation layer corrosion conditions. At the same time, due to the large internal stress formed by the cold pressing of the plate in this area, the internal stress causes the stress corrosion to occur when the surface passivation layer is destroyed.

Approach

① replace the crack or perforated plate, in the field with the translucent method to find plate cracks. ② adjust the operating parameters, so that it meets the design conditions. ③ evaporator maintenance assembly clamping size should meet the requirements, not the smaller the better. ④ evaporator plate material reasonable match.