Vacuum Degassing

Every substance changes according to temperature and pressure. Mixtures of substances can therefore be separated when one substance evaporates at another point than the other. Under vacuum, evaporation is possible at lower temperatures. This technique can be used in degassing processes. To remove dissolved gases from liquids, especially water or aqueous solutions.

According to Henry's law, the amount of dissolved gas in a liquid is proportional to its partial pressure. So, placing a solution under reduced pressure makes the dissolved gas less soluble. Sonication and stirring under reduced pressure can usually enhance process efficiency. This technique is often referred to as vacuum degasification or simply degassing.

Vacuum degassing systems are often a combination of a vacuum pump and a trap. The vacuum pump reduces the pressure inside the system. The trap protects the vacuum pump by preventing liquids and particles from reaching it. In the cases of heavy condensable loads, a condenser can be used to collect the valuable compounds. It can be installed upstream or downstream of the vacuum pump, according to the respective process requirements.

Vacuum is used in degassing installations like extruders, columns, or mixers. Vacuum degassing plays an important role in different applications such as:

Under vacuum, the evaporation of the gas can take place at a low temperature. This offers several advantages:

An important prerequisite when choosing the right vacuum pump for degassing is that it reaches the expected pressure range for the process step. Moreover, the vacuum pump should be able to handle liquids and small particles.

Typical vacuum pumps for vacuum degassing are liquid ring vacuum pumps, claw vacuum pumps and dry screw vacuum pumps.

Liquid ring vacuum pumps are the perfect choice for vacuum degassing as the vacuum pump often comes in contact with condensable vapors. The condensation of such vapors in the liquid ring is very efficient. Dry screw vacuum pumps are perfectly suited whenever the vapors can be valorized if not contaminated. Oil-lubricated rotary vane vacuum pumps are excellent when accumulation can be avoided in the oil.

The choice of the vacuum pump depends on the respective process requirements. The most suitable and proven Busch products for degassing are MINK, COBRA, DOLPHIN, HUCKEPACK and R5.

Busch solutions are used in all kinds of degassing applications. DOPHIN vacuum pumps, for example, play an important role in processes like sea water deaeration on offshore platforms or sparkling water degassing. Dry screw vacuum pumps are used in pharma and in the cosmetic industry to degas creams and pastes. Our vacuum technology is also present in plastics degassing in compounding processes, and in water degassing for recycling processes and food applications. Another possible field of application is the degassing of solvents in the chemical industry to avoid adverse side reactions. But also degassing of steel and metal to produce a purer grade.

You should consider the following in order to find the vacuum degassing solution that best fits your needs:

Extrusion is a common process in the plastics industry to melt, mix and homogenize plastics. The raw material is conveyed by a screw in a heated barrel. There, the plastic is melted by friction and heat to a viscous liquid. Which is then forced through a die into its final shape.

During the melting process in the extruder, the residual moisture evaporates. And, due to the increase in temperature and pressure, gases can sublimate from the plastic.

Vacuum ensures that these trapped vapors and gases are reliably extracted from the melt. For a high-quality final product without voids or other imperfections.

For many beverages, a precise quantity of dissolved carbon dioxide is essential. This applies not only to the production of mineral water, but also of soft drinks or even beer. However, the amount of CO₂ in spring water may vary.

To overcome this problem, several processes are required. And in every step, vacuum plays an important role.

The CO₂ is first extracted from the spring water by a vacuum deaeration system. It is then cooled and liquefied. Finally, it is reintroduced in precisely dosed quantities to the final product at the bottling stage. For consistent quality and a refreshing experience.

Vacuum degassing has become a crucial process in modern steel production. For example, it is the only way to manufacture certain grades of highly stressable steel alloys. Used in the automotive, aerospace and railway sector.

During the production process, molten steel can become infused with excess amounts of hydrogen and carbon. These imperfections affect the integrity and performance of the steel making it less ductile and thus less malleable.

In the past, hydrogen removal required the metal to be cooled down slowly. Thus, extending the manufacturing process. The modern method is to extract hydrogen under vacuum. For faster production of high-quality steel with precisely defined properties.

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Vacuum deaeration is a commonly employed method in the oil and gas industry today. Packed towers are continuously evacuated with vacuum systems. Thus, extracting oxygen and other gases.

In offshore applications, the injection of seawater into the oil well is an essential procedure in crude oil production. It is often a crucial factor in achieving and sustaining economically viable production rates.

The water used has to be deaerated before. Because the oxygen would have an adverse effect on sulphate removal systems. Everything for a stable and economic production.

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