Plate heat exchangers often fail and measures failure: leakage, leakage
main reason:

1. L value is not enough pressure or pressure deviation.

2. The plates and gaskets are placed upside down.

3. The gasket is aging or the gasket material is improperly selected.

4. The gasket is not well bonded, and there is a defect in foreign matter or gasket.

Measures:

First check whether the nut of the clamping screw is loose and the clamping dimension is consistent with the installation drawing of the equipment. If the nut is loose, the clamping size is too large, the nut can be retightened and the clamping dimension is consistent with the drawing; if it still leaks, it needs to be opened. Check the gasket. If the gasket is removed from the gasket groove, re-stick it and replace it with damage. When most gaskets are damaged together, pay attention to re-select the gasket of suitable material.

Frequently faulty and faulty: string

Inspection method: Open the low-pressure side outlet vent during normal operation to check if the second liquid is mixed.

main reason

1. The plate has cracks.

2. The sheet is corroded and penetrated.

Measure: Use the plate inspection method described in 3.6 to find out if the problem plate is removed or replaced. Note that when the plate is increased or decreased, the A plate B plate should be added or subtracted in pairs.

Frequent faults and measures failure: increased pressure drop, low heat transfer efficiency

main reason:

1. Internal blockage.

2. Slab fouling.

3. The plates are arranged incorrectly.

4. The internal air is not drained.

Action: Do not disassemble the cycle cleaning or disassembly cleaning; check the plate arrangement to correct the error; drain the internal air.

Method for descaling tube bundle heat exchanger tube bundle

First, manual or mechanical methods

When there is slight blockage and fouling of the tube bundle, it is cleaned by manual or mechanical means such as cutting, wire brush, etc., and is mixed with compressed air, high pressure water and steam. When the pipe fouling is serious or all blocked, the pipe flushing drill (also known as the pipe boring machine) can be used for cleaning.

Second, the flushing method

There are two kinds of flushing methods: the first one is countercurrent flushing, which is generally used during the movement, or when parking for a short time. It is not necessary to disassemble the device, but the countercurrent secondary line should be preset on the equipment, when the fouling is not This method is more effective when it is serious. The second method is the high pressure water gun flushing method. Different rotating water gun heads can be used for different heat exchangers, which can be rigid or winding, and the pressure can be adjusted freely from 10MPa to 200MPa. The use of high pressure water to remove dirt, regardless of the tube, tube and housing. The high pressure water gun flushing heat exchanger works well. Wide range of applications.

Third, chemical descaling

The scale of the plate heat exchanger is mainly due to the poor formation of scale and the formation of coke deposits and adhesions of scale and grease. The chemical method is used for descaling. Firstly, the scale material should be analyzed and analyzed to find out the nature of the scale. It is possible to decide which solvent to use for cleaning. Generally, the sulfate and silicate scales are washed with alkali (soda ash, caustic soda, trisodium phosphate, etc.), and the carbonate scale is washed with acid (hydrochloric acid, nitric acid, phosphoric acid, hydrofluoric acid, etc.). The oily coke can be cleaned by using sodium hydroxide, sodium carbonate, washing powder, liquid detergent, sodium silicate and water in a certain ratio to prepare a cleaning solution. With chemical cleaning, the site needs to be re-piped and it takes time.

Basic principle of removing scale

Dissolution: The acid solution easily reacts with calcium, magnesium, and carbonate scale to form a soluble compound, which dissolves the scale

Peeling effect: The acid solution can dissolve the oxide on the metal surface. Destruction and scale bonding. Thereby, the scale adhering to the surface of the metal oxide is peeled off. And fell off.

Loose effect: For silicate and sulfate mixed scales, since the oxides of calcium, magnesium, carbonate and iron are dissolved in the acid solution, the residual scale becomes loose and easily washed away by the flowing acid solution. .

Air enthalpy action: After the acid solution reacts with calcium, magnesium and carbonate scale, a large amount of carbon dioxide is produced. Carbon dioxide gas is in the process of overflow. For the scale layer which is difficult to dissolve or dissolve slowly, it has a certain enthalpy power, so that the scale falls off from the heated surface of the heat exchanger..