Select an LNG submersible pump by matching its verified flow and differential-pressure requirements to the transfer duty, then confirming that the pump, motor, materials, and electrical arrangement suit the actual cryogenic service. Start with the process data—not a catalog model number—and document the LNG composition, operating temperatures and pressures, suction conditions, transfer route, and required control range. Because LNG is commonly handled near −162°C, equipment selection must account for cryogenic operation as well as hydraulic performance. At Dongzhao, we recommend reviewing the complete duty point and installation conditions before proposing a pump configuration.
Write down what the pump must transfer, between which points, and under what operating conditions. Typical duties may include moving LNG from a storage tank to a loading system, supplying a process line, or transferring product between vessels. These applications can have different flow profiles, pressure requirements, run times, and installation constraints, so the application name alone is not enough to select a pump.
Specify the required flow in m³/h, including the normal duty and any expected minimum or maximum operating points. Clarify whether the pump will run continuously, intermittently, or only during defined transfer cycles. If flow varies, tell the supplier how it is controlled and whether the system uses a control valve, variable-speed drive, or another method.
Do not select a pump using only the largest possible flow figure. A pump should be assessed against the actual operating range and the connected system, including pipe size, fittings, elevation changes, and downstream pressure. Ask for performance data covering the proposed duty rather than relying on a nominal rating without its test or operating conditions.
Describe the pressure at the source and destination, the elevation difference, and the expected losses through the transfer line and equipment. The supplier can use this information to determine the required differential pressure or total head. For reference, a pressure increase of 1 bar corresponds to roughly 24 m of LNG head if a density of 430 kg/m³ is assumed; the actual conversion changes with LNG density and operating conditions.
Use that relationship only as a screening calculation, not as a substitute for a system calculation. Provide the best available density or LNG composition data, and identify whether the destination pressure changes during transfer. A missing pressure requirement can lead to a pump that meets the flow target but cannot deliver it through the real system.
LNG is typically handled at about −162°C near atmospheric pressure, although the actual temperature and pressure depend on composition and process conditions. The pump and its motor are intended for submerged cryogenic service, so confirm the specified operating envelope rather than assuming that any submersible pump is suitable. Include normal, startup, shutdown, and any planned standby conditions in the review.
Provide the vessel or tank arrangement, minimum liquid level, pump immersion depth, and any restrictions near the inlet. Ask the supplier to review the available suction conditions against the proposed pump’s requirements. Low liquid level, unsuitable inlet geometry, or excessive system losses can contribute to unstable operation or reduced performance, so these details matter even when the pump is installed inside a tank.
Also explain how the system is filled, cooled down, and returned to service after a shutdown. Startup procedures and operating sequences should follow the equipment documentation and the site’s approved operating practices. If the transfer duty involves frequent starts or changing liquid levels, make that clear during selection.
Request confirmation of materials for the parts exposed to LNG and for components exposed to the surrounding environment. Material selection should reflect the specified cryogenic temperature, fluid composition, pressure, and applicable project requirements. Avoid assuming that a material is compatible based only on its use in another LNG system.
Review the pump hydraulics together with the motor, power cable, electrical connections, control equipment, and protective functions. Confirm the required voltage, frequency, starting method, control signals, and interface with the plant’s instrumentation. The supplier should identify the information needed to verify the proposed electrical arrangement for the installation and the applicable local requirements.
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Check mechanical dimensions and interfaces early. Important details include vessel openings, mounting arrangement, discharge connection, cable routing, lifting or service provisions, and access for inspection or replacement. A hydraulically suitable pump may still be impractical if its dimensions or connections do not fit the site design.
When evaluating quotations, compare each proposal against the same operating data and supply scope. Ask suppliers to state the flow and head or differential pressure at the specified duty, the applicable operating range, and any assumptions used in their selection. If proposals use different assumptions, resolve those differences before comparing price or delivery.
| Selection item | Information to provide or verify |
|---|---|
| Process duty | Flow, required pressure rise or head, transfer destination, and operating range |
| Fluid and conditions | LNG composition if available, temperature, pressure, and relevant operating cases |
| Installation | Tank or vessel arrangement, minimum liquid level, immersion depth, and connections |
| Electrical interface | Supply voltage and frequency, control method, cable requirements, and site protections |
| Supply scope | Pump and motor configuration, included accessories, documentation, and service responsibilities |
Confirm what performance documents, dimensional drawings, material information, operating instructions, and maintenance guidance are available for the proposed model. These documents help engineering, procurement, and operations teams check the selection before purchase and installation. Request clarification whenever a proposal does not state its operating assumptions or supply boundaries.
Confirm that the proposed pump can cover the required transfer conditions, including foreseeable changes in flow or destination pressure. Ask how operation should be controlled if the process varies, and whether the selected arrangement has limits that operators need to observe. The answer should be based on the supplier’s applicable performance information and the system data you provide.
Verify vessel fit, connections, power supply, control interfaces, and maintenance access with the project team. Check that the operating procedures address startup, shutdown, low liquid level, and abnormal conditions in line with the equipment instructions and site safety rules. For LNG service, the pump selection should be reviewed as part of the wider transfer system rather than in isolation.
Prepare one technical data sheet and issue it consistently to every supplier. Include normal and limiting operating conditions, a process sketch or piping information where available, vessel details, electrical requirements, and the intended control strategy. Mark unknown values clearly instead of allowing suppliers to assume them without review.
Ask for a technical clarification meeting before finalizing the purchase if the duty, installation, or operating range is not settled. Record agreed assumptions and exceptions in the quotation review so they can be carried into engineering and procurement documents. This disciplined approach helps buyers compare suitable options and identify missing information before it affects installation planning.
At Dongzhao, we support B2B buyers by reviewing the transfer duty, operating conditions, installation interface, and required supply scope for LNG submersible pump inquiries. To begin a selection discussion, provide your target flow and pressure rise, LNG temperature and pressure, tank or vessel arrangement, power supply, and control requirements. If some data is not yet available, identify the open items so we can clarify what is needed to assess a suitable configuration.
The right LNG submersible pump is the one supported by a clear match between the transfer system’s flow and pressure requirements, cryogenic operating conditions, materials, and installation interfaces. Start by documenting the full duty, then verify the proposed pump and motor arrangement against the site’s suction, electrical, and mechanical requirements. Before ordering, compare suppliers on the same assumptions and confirm the available technical documentation and scope of supply.
Your next step is to prepare a pump inquiry sheet with the process and installation data listed above, then send it to Dongzhao for a technical review. We can use those details to discuss a configuration aligned with your LNG transfer application and identify any information that still needs confirmation.
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