Heat exchanger fouling is a commonly occurring problem in different kinds of heat exchangers. It results in changing the heat transfer surface and reducing the overall heat transfer rate through that surface.
During fouling, the surface of a heat exchanger wall develops another layer of solid material. This can happen for a variety of reasons. But as a result, the heat transfer coefficient at the surface is drastically reduced, since the heat conducting wall metal is not in contact with the fluids any more. Instead, the wall is separated from fluid by a layer of 'fouling'. Fouling material prevents efficient heat transfer and reduces the efficiency of heat exchanger.
Heat exchanger fouling
Protect your coolers by installing Biowater units
What can Biowater units do?
Biowater containing millions of nanobubbles creates a microscopic barrier on the coolers inner surface, this increases the heat transfer rate and creates a film that deposits do not attache to. Below is a description of the different fouling types and how Biowater works.
Corrosion fouling occurs when the fluid corrodes the surface of the exchanger wall, developing a layer of corrosion. The accumulation of corrosion products can act as an insulator. It leads to increased energy consumption and reduced heat exchanger efficiency. The Biowater are excellent corrosion inhibitors and also creates a barrier that prevents corrosion on any type of material.
Scale is a hard, chalky deposit that can form on the surfaces of cooling towers. It is caused by the precipitation of dissolved minerals in the cooling water. These minerals can come from the water, the air, or the materials used to construct the cooler. The most common type of scale is calcium carbonate. Calcium carbonate is a relatively insoluble mineral, so it tends to precipitate out of solution when the water temperature drops. This is why scale is often found on the coldest surfaces in the cooler, such as the fill and the pipes. Other types of scale that can form in coolers include calcium sulfate, magnesium carbonate, and iron oxide. The type of scale that forms will depend on the composition of the water and the operating conditions of the cooler.
Scale can have a number of negative effects on coolers. It can reduce the efficiency of the cooler, increase the risk of corrosion, and damage the equipment. Scale can also be difficult and expensive to remove. Biowater units removes and prevents scaling.
Particulate fouling happens when there is low fluid velocity in certain areas of the fluid path. Because of the low fluid velocity, suspended particulate matter in the fluid can settle down on the heat exchanger wall. Over time a layer of such particulate material develops on the wall, reducing the heat transfer through it. Biowater breaks up particles so they easily mix with water.
Precipitation fouling occurs when the fluid flowing through the heat exchanger contains dissolved solids that can react and precipitate out of solution under certain conditions, such as changes in temperature, pressure, or chemical composition. Precipitation fouling also occurs because of deposition of material which was originally in the fluid stream. In that respect, it is similar to particulate fouling.
But in most cases of precipitation fouling, thedissolved matter in the fluid starts to precipitate due to change in fluid temperature. The change in temperature is highest at the heat exchanger wall. Hence some dissolve solids can precipitate out of the fluid and get deposited on the exchanger wall, resulting in fouling. Biowater breaks up particles so they easily mix with water.
Chemical reaction fouling
Chemical reaction fouling in heat exchangers refers to the buildup of reaction products on the surfaces of the heat exchanger, which can reduce its efficiency and cause damage. If the fluid flowing through the exchanger contains reactive species then the fluid can undergo a reaction at the heat exchanger wall surface. This reaction produces a solid product that adheres to the heat exchanger wall, resulting in fouling - for example, polymerization.
Note that this is different than the 'corrosion fouling', where the wall itself gets corroded. In case of chemical reaction fouling, the wall is chemically unchanged. But the fluid undergoes a reaction, producing fouling material.
This kind of fouling also happens because of temperature change in the fluid. High temperature change at the exchanger wall causes the fluids to react. The Biowater barrier prevents corrosion on any type of material and breaks up particles that easily mix with water.
Biofouling occurs when microorganisms, such as bacteria, algae, or fungi, grow and form colonies on the metal surfaces inside the heat exchanger. Organisms present in the fluid stream can get attracted to the warm surface of the heat exchanger wall. Here they can grow in size and reproduce, forming a layer of biological material. This is known as 'bio fouling'. The Biowater barrier removes and prevents biofilm growth and also kills above mentioned organisms when the negative charged nanobubbles collides with the positive charged organisms, this oxidizing process is one of the most powerful known harmless processes.