Pumps are necessary components inside an oil drilling rig. They’re designed to accelerate the transference of fluid from one location to another. Without pumps, refineries cannot operate, as oil displacement is essential to an oil rig’s entire operation. Below, we explore different types of pumps companies use in oil and gas downstream operations, their primary function, and pros and cons of each model.
The most common type of pump found in the oil and gas industry is undoubtedly the centrifugal pump. Centrifugal pumps contain one or more impellers that move fluid by rotation and draw fluid into the suction end of the pump and then, through centrifugal force, forces it out of the discharge end. This design allows the pumps to be used for a wide range of applications and are preferred for processes that handle low viscosity liquids and high flow rates. Centrifugal pumps can also handle dirty liquids or liquids with low viscosity as long as they do not contain air, vapors, or heavy amount of solids.
Centrifugal pumps are used in the upstream oil and gas industry as part of tri-phase or multiphase pumping application. These pumps serve a wide variety of applications with many types such as electric submersible pumps, which are used as a water and oil separator in which water can be re-injected into a reservoir without the lifting it to the ground surface. They can transport a significant amount of low viscosity liquids in a short period and can pump several hundred gallons of liquid per minute if the product is compatible.
A standard oil pump mechanically lifts liquid out of an oil well when there isn’t enough ground pressure to force the oil onto the surface. Oil pumps are used in onshore areas where oil is abundant, but the ground needs help releasing it. These pumps can deliver one to ten gallons of fuel with every stroke depending on the depth and the weight of the oil. Deeper extractions require more massive pumps to move the oil through a vertical discharge column (discharge head). A motor that drives the vertical motion to drive the pump shaft powers the pumps. The industry term for this movement is known as a ‘walking beam.’
Positive Displacement Pump
In contrast to centrifugal pumps, a positive displacement pump does not use impellers to move the fluid. Instead, they utilize rotating or reciprocating parts to push transport the liquid into an enclosed volume. This design creates pressure, which drives the liquid to its destination. A positive displacement pump is ideal for higher viscosity liquids that are transported at a lower flow rate but a higher pressure. An example of a positive displacement pump is a chemical injection pump.
Positive Displacement Pumps are utilized in the upstream phase of an oil refinery. They are a more compact unit, which increases the high-pressure ratio, making them among the most efficient types of pump, as well as a low-cost solution. Despite their affordability and efficiency, positive placement pumps do require extensive maintenance, partly due to mechanical part failures. They’re also noisier than a centrifugal compressor, which could raise issues in certain applications. Positive displacement pumps are not typically used in situations that demand high flow rates.
Oil Transfer Pump
An oil transfer pump is used to transfer glycol from a well to a holding tank during the midstream and downstream phase of oil refinement. Due to the high volume of activity that an oil pump engages in, they require extensive maintenance and repairs to continue working correctly. Transfer pumps create a variation in pressure that pushes fluid from location to another. Industrial scale slurry pumps can operate on electric, solar, hydraulic or gas power. Oil companies use transfer pumps to move flammable or corrosive liquids like oil, gas, or chemicals. These types of pumps are safe to use for these applications because the components are manufactured with corrosion-resistant metals which hold up well in hazardous environmental conditions.
A diaphragm pump is a type of positive displacement pump that uses both a valve and a diaphragm to draw oil and gas into a refinery chamber during the upstream and midstream phase of oil refinement. When the volume of a chamber increases, the pressure in the chamber reduces, and the fluid pours into the chamber. The diaphragm then moves down and forces the liquid out. Once the fluid has cleared the chamber, the diaphragm moves back into position, allowing more fluid to enter. This cycle continues while the pump is operating.
Due to their unique design, diaphragm pumps can transport large volumes of liquid and are ideal for refineries that are located over sizable oil sources. Diaphragm pumps are also far more wear resistant than positive displacement pumps because they have fewer moving parts or friction points that wear down the components. However, diaphragm pumps do suffer from ‘winks’ – small gaps in the process that can slow down the flow of fluid. Winks and low pressure are likely to occur over long distances.
Petroleum products move from the upstream sector into the midstream sector of the petrochemical industry. The midstream sector transports and stores natural gas and crude oils. This is where the petrochemical pump comes in. Companies use these types of pumps to process or refine chemicals during crude oil drilling and refining. Petrochemical pumps can be piston pumps, diaphragm pumps, mag drive pumps or another type of process pump or chemical pump.
Petrochemical pumps can operate at high rates of flow and pressure within a refinery system. One of the benefits of petrochemical pumps is that they prevent leaks; thus, they prevent hazardous environmental conditions. The simplistic design of the petrochemical pump, ease of use, and compactness give it the durability it needs to keep up with the demands of oil drilling. On the downside, petrochemical pumps can succumb to overheating, cavitations, and internal corrosion. Viscous, toxic, and corrosive fluids can also wear down the impellers over time.
Whether used during the upstream, midstream, or downstream phase, pumps give gas, oil, and other fluids enough energy to flow from one location to another. Centrifugal, oil, positive displacement, oil transfer, diaphragm, and petrochemical pumps are essential in delivering oil from the ground to a tanker, then to a refinery, and then on to storage. They are also useful for methanol injection, glycol pumping, chemical processing, gas sweetening, and water disposal. Pumps offer an efficient solution for transporting chemicals. Each type of pump explained above is integrated into a refining system for a specific purpose and are crucial in transporting or purifying different fluids.