How to effectively clean plate heat exchanger fouling

In recent years, it has the characteristics of light weight, small footprint, low investment, high heat transfer efficiency, flexible assembly and easy scaling. Gradually promote the use of technology in all walks of life. However, because the plate cooler smooth flow smaller. After scaling, the heat transfer efficiency of the plate heat exchanger is reduced, which affects the safety of the equipment and the normal use of the user. Therefore. Solve the plate heat exchanger cleaning, to prevent the formation of scale. Will be an important issue to ensure safe production and economic operation.

Plate heat exchanger in use. Because of the improper operation of water treatment equipment. The water quality control is not up to standard, and the softened water is injected into the system, so that the calcium, magnesium and carbonate in water can be decomposed into calcium carbonate and magnesium hydroxide

The utility model is formed on the heating surface of the heat exchanger. Because of the poor thermal conductivity of the scale, resulting in a reduction in the efficiency of heat exchanger and severe heat energy. Thus affecting the heat transfer effect.

Scaling method for plate heat exchanger

Selection of cleaning agent

The choice of cleaning agent, currently used in pickling, which includes organic acids and inorganic acids. Organic acids are mainly oxalic acid, formic acid and so on. Inorganic acids are: hydrochloric acid, nitric acid, etc.. According to the fouling of heat exchanger and the analysis of process, material and scale composition:

Heat exchanger smooth flow area is small, the internal structure is complex, if the cleaning liquid precipitation is not easy to discharge.

The heat exchanger is made of nickel titanium alloy, and the hydrochloric acid is used as the cleaning solution, which can easily produce strong erosion to the plate and shorten the service life of the heat exchanger.

The results showed that formic acid was the best solution. The addition of buffer and surface active agent in the formic acid cleaning solution, the cleaning effect is better, and can reduce the erosion of the cleaning liquid to the plate. Through the study of scale samples, the results show that formic acid can effectively remove scale. Through acid soaking test, it is found that formic acid can effectively remove the scale attached to the plate, and it also has little effect on the heat exchanger plate.

Basic principles of scale removal

Solution: acid solution easily with calcium, magnesium, carbonate salt water scaling reaction, naturally soluble compounds, so that the scale dissolved.

Stripping: the acid solution dissolves the oxide on the surface of the metal. So that the scale is attached to the surface of the metal oxide. And fall off.

Gas lift: the acid solution reacts with calcium, magnesium and carbonate salt water to produce a large amount of carbon dioxide. Carbon dioxide gas in the process of overflow. For the scale layer which is difficult to dissolve or dissolve slowly, it has a certain lifting power, which causes the scale to fall off from the surface of the heat exchanger.

Loose role: for containing silicate and sulfate mixed scale, because the calcium and magnesium, carbonate and iron oxide dissolved in acid solution, the residual scale will become loose, it is easy to be washed down the acid solution.

Measures to prevent fouling of plate heat exchanger

Strict operation of the water quality, the system must be in the water and soften the tank in the water to soften the water quality testing, qualified to note the pipe network.

When the new system is put into operation, the heat exchanger should be separated from the system for a period of time, then the heat exchanger and the system can be avoided.

In the whole system, the cleaning device and the filter should be cleaned on time, and the pipe network should be kept clean.