Misunderstandings about plate heat exchange equipment

What are the misconceptions that can be said.

We all know that the application of plate heat exchange equipment in the society is more and more extensive, many consumers for the plate heat exchange equipment is not very comprehensive, there are often some misunderstandings, so today's plate heat exchange equipment to the majority of users to briefly introduce what misunderstandings exist, let's take a look. Many users think that the wall thickness of plate heat exchange equipment is good, in fact, the thickness of the wall thickness is not directly related to the corrosion resistance, because this is divided into materials, the general cast iron heat exchanger is not easy to be damaged by corrosion, first of all, the cast iron material itself has good oxidation and corrosion resistance, not because of its wall thickness. In recent years, with the continuous development of the heat exchanger industry, many heat exchanger manufacturers have begun to try to solve the anti-corrosion problem of steel heat exchangers by increasing the wall thickness, which is actually a completely wrong idea.

I would like to remind you that the corrosion of plate heat exchange equipment is local corrosion of small holes, and it is not uniform corrosion, so many manufacturers will now use stainless steel or carbon steel materials, so that the corrosion resistance is relatively good, so users can choose the material of plate heat exchange equipment according to their specific situation. The better the coating in the plate heat exchange equipment, the more corrosion resistance, this statement is wrong, and now many heat exchanger manufacturers are divided into two kinds of internal anti-corrosion coatings: one coating is an organic coating, and now this organic coating is generally used.

This coating is mainly to achieve the effect of anti-corrosion by isolating and not allowing water to come into direct contact with the substrate, but the coating is bonded together with the body similar to glue, and the surface treatment of the substrate is very high, otherwise the coating is prone to peeling, which is the biggest defect of the organic coating; The other is an inorganic coating, represented by zinc-based chromium salts, which are chemically bonded to the substrate at high temperatures, with strong adhesion and not easy to peel off. However, the process requirements are extremely strict, and the quality of its coating can only be guaranteed by strictly controlling the individual process parameters.

What is the specific content of the application of plate heat exchanger, the following Zhongda Consulting will answer for you.

1.Refrigeration: Used as a condenser and evaporator.

2.HVAC: intermediate heat exchangers used with boilers, intermediate heat exchangers for high-rise buildings, etc.

3.Chemical industry: soda ash industry, ammonia synthesis, alcohol fermentation, resin synthesis cooling, etc.

4.Metallurgical industry: aluminate mother liquor heating or cooling, steelmaking process cooling, etc.

5.Machinery industry: all kinds of quenching fluid cooling, reducer lubricating oil cooling, etc.

6.Electric power industry: high-voltage transformer oil cooling, generator bearing oil cooling, etc.

7.Paper industry: bleaching process heat, heating slurry washing, etc.

8.Textile industry: viscose silk alkali aqueous solution cooling, boiling nitrified fiber cooling, etc.

9.Food industry: juice sterilization and cooling, animal and vegetable oil heating and cooling, etc.

10.Grease process: soap-based atmospheric pressure drying, heating or cooling of various process liquids.

11.Central heating: Waste heat district heating of thermal power plants, heating of bathing water.

12.Others: petroleum, medicine, shipbuilding, seawater desalination, geothermal utilization.

Plate heat exchanger is a high-efficiency heat exchanger formed by stacking a series of metal sheets with a certain corrugated shape. Thin rectangular channels are formed between the various plates, through which heat is exchanged. Plate heat exchanger is an ideal equipment for liquid-liquid and liquid-steam heat exchange.

It has the characteristics of high heat exchange efficiency, small heat loss, compact and lightweight structure, small footprint, wide application and long service life. Under the same pressure loss, its heat transfer coefficient is 3-5 times higher than that of tubular heat exchanger, and the floor area is one-third of that of tubular heat exchanger, and the heat rate can be as high as more than 90%. [1]

There are two main types of plate heat exchangers: frame type (detachable) and brazing type, and there are three main types of plate forms: herringbone corrugated plate, horizontal straight corrugated plate and tumor-shaped plate. [2]

Calculate it this way: the temperature at which the hot medium goes in minus the temperature at which the hot medium comes out = ? Then the temperature at which the cold medium comes out minus the temperature at which the cold medium goes in = ? The closer the two numbers are, the better the heat transfer effect.

The plate heat exchanger should be tested before leaving the factory to see whether the pressure drop meets the heat exchange requirements. If the heat exchange effect cannot be achieved after installation at the user's place, first, the data given by the user may be inaccurate, or the technology is completely selected according to the selection software, without fully considering the complexity of the user's working conditions.

Look at the temperature difference between your inlet and outlet water, whether it meets the design requirements at that time, and look at the lower pressure gauge to see if the pressure drop is within the allowable range.