A corrosive fluid is a fluid that erodes and damages the materials with which it comes in contact. Metals, stone, glass, and even certain types of plastics are susceptible to corrosive fluids or chemicals. Corrosive fluids or chemicals typically fall into six categories: strong acids, weak acids, strong bases, weak bases, dehydrating agents, and oxidizing agents. Some chemicals may fall into more than one category; for example, sulfuric acid is both a strong acid and a dehydrating and oxidizing agent. Corrosive materials may also fall into other hazard categories, such as toxic (poisonous) or flammable. It follows that corrosive liquids pose a danger to humans.
Understanding the liquid
When pumping hazardous liquids in oil and gas dewatering, such as flammable, combustible, toxic and corrosive chemicals, several factors must be considered. These factors are critical to selecting the right chemical pump for the job.
First, the characteristics of the fluid being pumped need to be considered. It needs to be determined what type of fluid is being pumped, and what the characteristics of that fluid are. Key fluid data include details such as concentration, specific gravity, temperature resistance, viscosity, flammability (if any), and solids content.
Chemical pump selection requirements
To ensure that the pump is properly sized, the user must also consider the pump manufacturer’s head-capacity curve. Pump curves (also known as pump selection curves, pump efficiency curves or pump performance curves) provide the information needed to determine the pump’s ability to produce flow under conditions that affect machine performance.
An accurate reading of the pump curve (or consultation with a pump specialist) ensures that the user gets the correct pump for the application variables, such as: head (as the energy required to discharge water from the pump to an equivalent height expressed in metres); flow (the volume of liquid to be moved in a given time period, i.e. litres per minute [L/min] or cubic metres per hour [m3/h]); revolutions per minute (rpm); impeller size, in relation to pump performance-related; power; efficiency.
The right magnetic pump for the application
Magnetic drive pumps are the most common equipment used to transfer corrosive fluids. Magnetic pumps are energy efficient, available in either vertical or horizontal versions and in a wide range of sizes, designed to pump flows from a few litres per minute to tens of litres per minute.
When pumping corrosive fluids, magnetic pumps have a simple structure and no wearing parts such as mechanical seals and bearings, thus providing a high degree of reliability and stability for long-term stable operation.
With corrosive fluids, leaks can cause harm to humans and can also cause extensive damage to the surrounding infrastructure. Magnetic pumps are magnetically driven, eliminating the need for mechanical seals and avoiding the risk of leaks, which can effectively prevent environmental and human hazards from fluid leakage.
In addition, there are downtime and cost considerations (or mean time between failures) when the pump must be taken out of service and repaired. The low maintenance costs of magnetic pumps, the lack of frequent replacement of wearing parts such as mechanical seals and bearings and the simplicity and ease of maintenance make them a reliable, safe and economical choice when transporting corrosive liquids.
Suitable materials for chemical pump bodies
Choosing the right material for pump construction is very important, especially when moving corrosive fluids. Otherwise, components that encounter corrosive fluids (such as gaskets and O-rings) can corrode, which can affect pump performance and service life.
Commonly used corrosion-resistant materials for magnetic pumps include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluoroelastomer (FKM), polypropylene (PP), polyethylene (PE) and ceramics. These materials have excellent corrosion resistance and can withstand most acids, alkalis, salts and other corrosive liquids, and are therefore commonly used in pump bodies, impellers, seals, O-rings, bearings and other components of magnetic pumps. Choosing the right material ensures pump performance and longevity, and increases the reliability and stability of the pump.
Ask the professionals at QEEHUA PUMP
While this is not a comprehensive guide to pump selection when transporting corrosive fluids, it will hopefully provide the user with a snapshot of the challenges faced when selecting a pump and some of the key factors that need to be considered. There are many factors to consider, from the type of fluid being conveyed to choosing the right pump material of construction.
The user should first gather information about the fluid to be pumped, including the nature of the fluid, temperature, viscosity, pH value, solids content, etc. Secondly, gather information about the application requirements and environmental conditions, such as flow rate, head, pressure, temperature, altitude, ambient temperature, etc.
Then consult the professionals at QEEHUA PUMP, who can advise on the selection of the right pump for the job, taking into account all the above factors. Our professionals can advise you on the best pump solution for your specific needs and application environment.