How to pump Glycol: Glycol Types
Where Is Glycol Used?
Glycols are versatile liquids used for cooling, heating, and protective applications. When mixed with water, they protect against freezing, especially in engine cooling systems, while also acting as effective heat-transfer fluids to help maintain system temperatures. Glycols are also used in a range of industries, including varnishes, paints, polishes, inks, cosmetics, polyurethane, and polyethylene production.
Because glycols have relatively low specific gravity and viscosity, they can be handled effectively with centrifugal pumps. This makes them suitable for various pumping applications, including cooling tanks connected to main engines.
Why Is Glycol Used?
Glycols are favoured not only for their versatility but also for their cost-effectiveness. Their inert nature and broad chemical compatibility allow the use of less expensive materials such as cast iron in closed-loop cooling systems. By contrast, alternatives such as seawater or brine require more expensive materials because of their corrosive nature.
Glycol Types
Glycol is commonly used in one of four forms: ethylene glycol, propylene glycol, mono ethylene glycol, or triethylene glycol.
Ethylene glycol is used in industrial processes such as cooling and in the applications mentioned above. It is toxic if consumed by humans.
Propylene glycol is non-toxic and is used in food and medicine to absorb excess water while maintaining moisture in medicines and dissolving colours and flavours.
Mono ethylene glycol (MEG) is typically used as a component of coolants, antifreeze, and deicers, as well as in the manufacture of polyester fibres.
Triethylene glycol (TEG) is used in the oil and gas industry to dehydrate natural gases such as carbon dioxide (CO₂), hydrogen sulfide (H₂S), and other gases containing oxygen.
Important Considerations When Pumping Glycol
When pumping glycols, several important factors must be considered to ensure efficient and safe operation. These include:
Chemical Compatibility: It is essential to select pump materials that are compatible with glycols. Stainless steel, certain plastics, and corrosion-resistant alloys are commonly used for this purpose. Incompatible materials can lead to corrosion and premature pump failure.
Viscosity: Glycols have higher viscosities than water, which can affect pump performance and the power absorbed at a duty point. Choosing a pump with adequate kW rating and a design optimised for viscous fluids is essential to maintain the desired flow rates and pressure levels.
Temperature Sensitivity: Glycols show temperature-dependent changes in viscosity and density. Pump selection should account for the operating temperature range to ensure proper performance under varying conditions. In addition, measures such as insulation and heat tracing may be needed to prevent glycol from freezing in cold environments.
Seal Selection: Seals play a critical role in preventing leakage and ensuring the reliability of glycol pumps. Mechanical seals or packing arrangements should be selected based on compatibility with glycols and the specific application requirements.
Maintenance Requirements: Regular maintenance is essential for extending the service life of glycol pumps and minimising downtime. This includes monitoring for signs of wear, checking seal integrity, and lubricating moving parts as necessary.
Safety Considerations: Handling glycols requires adherence to safety protocols to prevent exposure risks. This includes proper ventilation in pump rooms, use of personal protective equipment, and compliance with relevant regulatory standards.
Environmental Impact: Spills or leaks of glycols can have environmental consequences. Implementing spill containment measures and proper disposal procedures is essential to minimise the environmental impact of glycol pumping operations.
By carefully considering these factors, engineers and operators can ensure reliable and efficient pumping of glycols in various industrial applications while maintaining safety and environmental responsibility.
