Cryogenic Liquid Pumps: Domestic Replacement and Green Energy Efficiency

Cryogenic liquid pumps are specialized equipment designed for transporting ultra-low temperature liquids (such as LNG, liquid oxygen, liquid nitrogen, liquid helium, etc.) below -150℃, and are widely used in energy, medical, scientific research and other fields. The following is a systematic introduction from the aspects of technical principles, product characteristics, application scenarios, technological innovation and market development:

I. Core Technologies and Working Principles

1. Structural Design

Submerged Structure: The motor and pump body are integrated into a sealed container and completely submerged in cryogenic liquid, eliminating the risk of shaft seal leakage. For example, Neppump's submerged pumps adopt a hydraulic modular design, optimize performance through CFD flow field analysis, and verify reliability through -196℃ liquid nitrogen testing.

Sealless Technology: Optimex's wet stator pumps eliminate dynamic seals, and the motor windings are in direct contact with cryogenic liquid, eliminating internal ignition hazards, making them suitable for flammable and explosive media such as LNG.

2. Material Selection

Low-Temperature Alloys: Impellers and bearings are made of austenitic stainless steel (such as 304L, 316L) or aluminum alloys, which maintain toughness at -196℃ and avoid cold brittle failure.

Special Coatings: Some high-end products adopt ceramic coatings or polytetrafluoroethylene (PTFE) treatment to reduce friction coefficient and enhance corrosion resistance.

3. Power Drive

Permanent Magnet Synchronous Motor: Neppump's high-efficiency********** magnet motors increase efficiency by 30% and do not require gearboxes, reducing mechanical losses.

Frequency Conversion Control: Intelligent sensors dynamically adjust rotational speed, reducing energy consumption by 40%. The annual electricity savings are equivalent to a reduction of 1.2 tons of CO₂ emissions, in line with carbon neutrality goals.

II. Product Characteristics and Key Parameters

1. Performance Advantages

Extreme Temperature Adaptability: Operating temperature ranges from -253℃ (liquid hydrogen) to -162℃ (LNG), pressure range of 35-150MPa, and flow rate up to 150 m³/h.

High Reliability: Adopting self-lubricating bearings and maintenance-free design. For example, Neppump's pump body has a service life of 40 years, and Optimex's wet stator pumps have no risk of seal leakage.

Cavitation Resistance: Impellers adopt cavitation-resistant design; for instance, the CP-LNGP series ensures stable operation in LNG transportation by optimizing the hydraulic model.

2. Safety Design

Explosion-Proof and Isolation: The motor is isolated from the liquid to prevent flammable gases from contacting the external air; some models are equipped with pressure sensors and vibration monitoring to provide real-time early warning of cavitation and impurity blockage.

Multiple Protections: Safety valves, emergency shutdown systems and thermal insulation layers (such as vacuum jackets) prevent cryogenic liquid leakage and heat intrusion.

III. Application Fields

1. Energy Industry

LNG Industry Chain: Used in LNG receiving terminals, transport ships and refueling stations. For example, Cryostar's magnetic levitation bearing pumps achieve efficient transportation in large-scale LNG projects.

Hydrogen Energy Development: Liquid hydrogen pumps (-253℃) have entered the R&D stage, providing support for hydrogen fuel cell vehicles and rocket propellant refueling.

2. Medical and Scientific Research

Organ Transportation and Preservation: Portable cryogenic pumps have successfully induced deep hypothermia in pig model experiments, providing a new solution for emergency treatment and organ transplantation.

Superconducting Technology: Provide liquid helium cooling for MRI equipment and particle accelerators; for example, Optimex's pumps are used for -101℃ ethylene transportation to support superconducting experiments.

3. Industrial and Chemical Sectors

Air Separation Systems: Transport liquid oxygen and liquid nitrogen to the iron and steel, electronics industries. For example, Sichuan Air Separation's cryogenic pumps achieve stable gas supply in air separation units.

Semiconductor Manufacturing: Ultra-low temperature capture pumps are used in etching and coating processes to maintain a high vacuum environment, with the localization rate gradually increasing to 45%.

IV. Technological Innovation and Market Trends

1. Intelligent Upgrading

Internet of Things (IoT) and AI: Intelligent pumps are equipped with sensors to monitor temperature, pressure and vibration data in real time, supporting remote operation and maintenance as well as predictive maintenance. For example, more than 40% of new orders in 2025 will integrate edge computing capabilities.

Magnetic Levitation Technology: Superconducting magnetic levitation bearings are applied to submerged pumps, eliminating mechanical friction, improving efficiency and extending service life. For example, the energy consumption of a certain model is reduced by 30%.

2. Green Energy-Saving Technology

Energy Efficiency Optimization: IE5 ultra-high efficiency motors and microchannel condensers reduce energy consumption by 40%. Refrigerants use natural refrigerants such as R290, with a GWP value***** 1/4000 of traditional refrigerants.

Cold Energy Utilization: LNG cryogenic pumps recover cold energy for power generation or refrigeration; for example, the cold energy utilization rate of a certain project is increased by 30%.

3. Domestic Replacement and Globalization

Rise of Domestic Enterprises: Shenyang Blower Works Group and Hangzhou Oxygen Plant Co., Ltd. have achieved breakthroughs in localization of LNG pumps, with a market share of 47% in 2024, and some high-end models have entered the demonstration application stage.

International Competitive Pattern: Foreign brands such as Cryostar and Leybold still dominate the high-end market, but domestic enterprises are gradually replacing imports through cost-effectiveness and localized services.

V. Selection and Maintenance Recommendations

1. Selection Key Points

Medium Characteristics: Select materials according to temperature (such as LNG at -162℃ or liquid nitrogen at -196℃) and corrosiveness.

Operating Conditions Requirements: Flow rate, pressure, installation environment (such as indoor vertical or outdoor horizontal) and explosion-proof grade.

Energy Efficiency and Cost: Frequency conversion pumps have lower long-term operation costs, with an investment payback period of approximately 2-3 years.

2. Maintenance Guide

Pre-Cooling Operation: Purge with dry nitrogen before startup to prevent water from freezing and damaging components.

Seal Inspection: Regularly replace mechanical seals or packing to prevent cryogenic liquid leakage.

Lubrication Management: Use low-temperature grease to ensure the normal operation of bearings and transmission components.

VI. Industry Standards and Certifications

International Standards: API 610 (Centrifugal Pumps), ASME B31.3 (Process Piping).

National Standards: GB/T 28777 Cryogenic Liquid Pumps, GB 19762 Minimum Allowable Values of Energy Efficiency for Centrifugal Clean Water Pumps.

Certification Requirements: ATEX Explosion-Proof Certification, ISO 9001 Quality Management System Certification, etc.

Conclusion

As core equipment in cryogenic engineering, cryogenic liquid pumps play a key role in energy transformation, medical progress and scientific research breakthroughs. With the development of materials science and intelligent technology, their energy efficiency, reliability and adaptability are constantly improving. In the future, domestic replacement and green energy conservation will become the main themes of the industry. Enterprises need to focus on technological innovation and segmented markets to cope with the challenges brought by global competition and carbon neutrality goals.

（注：文档部分内容可能由 AI 生成）