Pumps for multiphase-liquid/gas applications: how to choose the right technology

In the world of industrial fluid handling, multi-stage pumps are an advanced and increasingly popular technical solution for handling complex mixtures containing both liquid and gas. But how do you choose the most suitable technology depending on the composition of the fluid to be handled? In this article we offer a technical and operational overview to guide the choice, also presenting a concrete case from the mining sector.

“Light” multiphase applications: when gas is a secondary component

The first scenarios to consider are those where there is little gas or air content in the fluid, generally less than 50-60%. These scenarios, often categorized as “light” multiphase applications, include:
– Tank stripping operations, where an inhomogeneous liquid/gas mixture is created at the end of tank emptying.
– Systems handling volatile liquids, which partially evaporate as early as the pump suction phase.
– Foamy mixtures, where the presence of air bubbles affects hydraulic behavior.

In these cases, it is essential to employ a pump capable of maintaining flow continuity even in the presence of inhomogeneous gas phases.

High gas applications: Oil & Gas & beyond

In the most critical contexts, such as upstream applications in the oil and gas industry, gas percentages of up to 99 percent by volume are reached. Here the behavior of the mixture changes dramatically: the pump must be able to handle a fluid that behaves almost like a gas, but must still be able to retain a liquid part that is essential for lubrication and sealing inside the pumping chamber. The use of multiphase pumps in these applications makes it possible to reduce the number of machines installed (separate for gas and liquid), to exploit the gas instead of having to eliminate it (by burning it or re-injecting it into the well) , to greatly increase the productivity of depleting oil and gas wells, and to simplify the entire treatment plant, with significant advantages in terms of cost, productivityand reliability.

Why choose a twin screw pump

Among the various technologies available for handling multiphase fluids, the twin-screw pump stands out for its versatility, operational stability, and simple construction. Compared with solutions such as multistage centrifuges or progressive cavity pumps (PCPs), twin-screw pumps offer:
– Adaptable flow rate according to the needs of the downstream system and according to the percentage of gas coming from the well;
– Ability to handle mixtures with high variations in viscosity and density, as well as with solid particulates;
– Self-priming and continuous operation, even with high gas percentages;
– Absence of pulsation, making it ideal for applications where oil wells are sensitive to variations in surface operating conditions;
– Ease of maintenance and long operating life, especially in aggressive environments.

Customized configurations: materials, profiles and accessories

A great advantage of multiphase screw pumps is their ability to be adapted to specific conditions. Possible customizations include:
– Special materials for wetted parts (such as Duplex, Super Duplex, Hastelloy®, Inconel®);
– Surface hardeners to increase abrasion resistance in low lubrication environment in the pump chamber;
– Screw profiles optimized for specific flow rates or multiphase behavior;
– Dual mechanical seals suitable for handling high gas rates;
– Liquid recirculation systems integrated in the pump body or at the pump side.
– Pump management via control panel with programmable and customizable PLC

These are complemented by accessories that are essential for the safe and efficient operation of the machine: control instrumentation, block and check valves, systems with inverters (VFDs) for dynamic speed regulation, and instrumental redundancies for highly critical installations.

Parallel systems and Duty/Standby configurations

To ensure continuous operation even in the event of failure or maintenance, multiphase pumps can be installed in parallel or in a Duty/Standby configuration. This type of architecture allows both doubling the flow rate and increasing the reliability of the system, ensuring continuous operation even in harsh or isolated environments.

Case study: mining sector – pumping liquid containing high percentages of solids, together with liquid and gas in similar percentages

A concrete example comes from the Mining sector, where 3P Prinz supplied a twin-screw pump for conveying a highly abrasive, multiphase fluid consisting of:
– Sodium and potassium salts,
– Saturated salt water,
– Air, in a high percentage.

The client had previously employed other technologies, both centrifugal and positive displacement pumps of various types, which had proved unsatisfactory due to high wear and constant maintenance required or even poor performance. The solution proposed by 3P Prinz, on the other hand, ensured:
– Maximum efficiency and continuity of operation,
– Drastic reduction of maintenance, despite the fact that the pumped product is highly abrasive
– Better adaptation to variable fluid conditions.

Conclusions: tailored advice for every application

Choosing the right multiphase pump is not just about evaluating a data sheet-it is a process that involves fluid analysis, defining operating conditions, and selecting the most suitable technology. For this reason, 3P Prinz’s technical and sales team is available to offer customized advice based on experience, custom design and proven solutions in high-complexity industries.

Contact us today to study together the best multiphase pump for your application.