Hydrogen Compressor

Hydrogen Compressor

Oil-free hydrogen compressor — 63 models, 0.1–100 m³/min, 0.20–6.0 MPa, 7.5–2000 kW. From-atmospheric and booster inlet configurations. Chlor-alkali, electrolysis, refinery, FCEV fuelling.

Category:

Hydrogen Compressor — Oil-Free Reciprocating Piston Series

Oil-Free Reciprocating Piston Compressor for Hydrogen and Hydrogen-Containing Gas Streams · Discharge Pressure 0.20–6.0 MPa · Flow 0.1–100 m³/min · 7.5–2000 kW · 63 Standard Models

The hydrogen compressor is an oil-free reciprocating piston compression system purpose-built for the unique physical, chemical, and safety requirements of hydrogen gas (H₂) and hydrogen-rich process streams. Hydrogen is the lightest gas — approximately 14 times lighter than air — and presents extreme leakage risk through conventional shaft seals and piston ring clearances that are acceptable in heavier gas compressors. It forms flammable mixtures with air across a very wide concentration range of 4% to 75% by volume. Its small molecular diameter causes hydrogen embrittlement of certain steels and rapid permeation through polymer seals rated for other gases. It burns with an invisible flame, making leakage-initiated fires extremely difficult to detect. All of these properties demand dedicated hydrogen compressor design that cannot be achieved by modifying an air compressor or a standard gas compressor.

This series covers 63 standard models with flow from 0.1 m³/min to 100 m³/min at discharge pressures of 0.20 to 6.0 MPa. Inlet conditions span from micro-positive-pressure (near-atmospheric) for hydrogen production and recovery applications to high-pressure inlets (0.04 to 2.40 MPa) for booster compression stages. Mechanical configurations include twin-column single-stage (Twin-col. single-stage), twin-column two-stage (Twin-col. two-stage), twin-column three-stage (Twin-col. 3-stage), twin-column four-stage (Twin-col. four-stage), and four-column four-stage (Four-col. four-stage) arrangements matched to the specific pressure ratio and flow range of each application. Drive power ranges from 7.5 kW to 2,000 kW with voltage options of 380 V, 6 kV, and 10 kV. Custom single-unit capacity within 5.5 kW to 2,000 kW available on request for both oil-free hydrogen compressors and hydrogen booster compressors.

All models use oil-free PTFE composite piston rings with hydrogen-service distance piece isolation, hydrogen-specific labyrinth shaft seals or double mechanical seals with purge gas, hydrogen-compatible elastomers and gasket materials, micro-positive-pressure or controlled inlet design to prevent air ingress, explosion-proof electrical equipment, and stainless steel or hydrogen-service alloy valve and seal components. Proven in chlor-alkali electrolysis hydrogen recovery, water electrolysis hydrogen filling stations, petroleum refinery hydroprocessing, methanol and ammonia synthesis feed, hydrogen fuel cell vehicle fuelling stations, and hydrogen energy storage installations.

Hydrogen compressor — oil-free reciprocating piston compressor for hydrogen gas, H2 compression at 0.20 to 6.0 MPa, twin-column multi-stage configuration with explosion-proof motor for chlor-alkali, electrolysis, refinery, methanol synthesis and hydrogen fuelling station applications
Oil-free hydrogen compressor series — 63 standard models covering 0.1 to 100 m³/min at 0.20 to 6.0 MPa with multi-stage reciprocating configurations for hydrogen production, recovery, refinery feed, and hydrogen energy applications
Oil-Free PTFE Piston Rings
0.20–6.0 MPa
0.1–100 m³/min
63 Standard Models
7.5–2000 kW
380 V / 6 kV / 10 kV
Explosion-Proof Motors
High-Pressure Inlet Options

Typical applications: Chlor-alkali electrolysis hydrogen recovery and compression · Water electrolysis green hydrogen production · Petroleum refinery hydroprocessing feed · Methanol and ammonia synthesis hydrogen feed · Hydrogen fuel cell vehicle (FCEV) fuelling stations · Hydrogen energy storage compression · Semiconductor fab hydrogen supply · Petrochemical hydrogenation reactors · Edible oil hydrogenation · Steel plant hydrogen annealing furnaces · Glass plant hydrogen atmosphere furnaces · Syngas hydrogen fraction compression

Technical Parameters — Full Model Range (63 Models)

Oil-Free Hydrogen Compressor and Hydrogen Booster Compressor · Discharge Pressure 0.20–6.0 MPa · Flow 0.1–100 m³/min

Flow is stated in m³/min at inlet conditions. Inlet condition notation: “micro-positive-pressure” indicates near-atmospheric inlet design preventing air ingress; bracketed pressures e.g. “(inlet 2.10 MPa)” indicate high-pressure booster inlet configurations where hydrogen is received at the specified inlet pressure from an upstream stage or vessel. Stage count (single-stage / two-stage / three-stage / four-stage) is selected based on the overall pressure ratio required. Custom single-unit capacity within 5.5 kW to 2,000 kW available on request for oil-free hydrogen compressors and hydrogen booster compressors.

No. Model Pattern Flow (m³/min) Inlet Condition Discharge (MPa) Dimensions L×W×H (mm) Weight (t) Power (kW) Voltage (V)
1 ZW-0.1/21~25 Twin-col. two-stage 0.1 Inlet 2.10 MPa 2.50 720×763×1640 0.80 7.5 380
2 ZW-0.25/13~24 Twin-col. two-stage 0.25 Inlet 1.30 MPa 2.40 1550×985×2013 1.00 11 380
3 ZW-1.1/11.5~24.5 Twin-col. two-stage 1.1 Inlet 1.15 MPa 2.45 2495×1800×2945 1.80 37 380
4 ZW-1.1/25 Twin-col. 3-stage 1.1 Micro-positive-P 2.50 1550×1340×1910 2.83 30 380
5 ZW-1.5/8 Twin-col. single-stage 1.5 Micro-positive-P 0.80 720×763×1274 0.58 15 380
6 ZW-1.5/25 Twin-col. 3-stage 1.5 Micro-positive-P 2.50 1550×1340×1910 3.00 30 380
7 ZW-2/4 Twin-col. two-stage 2 Micro-positive-P 0.40 1520×800×1360 0.58 15 380
8 ZW-2/11 Twin-col. two-stage 2 Micro-positive-P 1.10 720×763×1475 0.80 18.5 380
9 ZW-3/7 Twin-col. two-stage 3 Micro-positive-P 0.70 1520×800×1360 0.58 22 380
10 ZW-3.5/0.2~8.6 Twin-col. two-stage 3.5 Inlet 0.02 MPa 0.86 2250×1296×2200 2.00 30 380
11 ZW-3/30 Twin-col. 3-stage 3 Micro-positive-P 3.00 1920×1900×2825 3.50 45 380
12 ZW-4/8 Twin-col. two-stage 4 Micro-positive-P 0.80 2250×1296×2200 2.00 30 380
13 ZW-6/8 Twin-col. two-stage 6 Micro-positive-P 0.80 2250×1296×2200 2.10 45 380
14 3ZW-6/30 Twin-col. 3-stage 6 Micro-positive-P 3.00 1845×1660×2360 3.00 75 380
15 3ZW-8/20 Twin-col. 3-stage 8 Micro-positive-P 2.00 1845×1660×2360 3.00 75 380
16 3ZW-9.5/30 Twin-col. 3-stage 9.5 Micro-positive-P 3.00 1845×1660×2360 3.50 110 380
17 ZW-13/30 Twin-col. 3-stage 13 Micro-positive-P 3.00 2764×2000×3277 6.00 160 380
18 ZW-15/8 Twin-col. two-stage 15 Micro-positive-P 0.80 2300×1800×2800 5.00 132 380
19 LW-2.1/8~120 Twin-col. 3-stage 2.1 Inlet 0.80 MPa 12.00 3200×1685×2430 6.50 160 380
20 LW-4.65/24~35 Twin-col. single-stage 4.65 Inlet 2.40 MPa 3.50 2400×1550×2350 4.50 185 380
21 LW-5.6/0.4~8.1 Twin-col. two-stage 5.6 Inlet 0.04 MPa 0.81 2250×1400×2200 3.50 55 380
22 LW-6/15 Twin-col. two-stage 6 Micro-positive-P 1.50 2280×950×2170 1.80 65 380
23 LW-9/3.5~34 Twin-col. two-stage 9 Inlet 0.35 MPa 3.40 3200×1685×2430 6.50 250 380
24 LW-10/4 Twin-col. single-stage 10 Micro-positive-P 0.40 2340×910×2070 1.80 55 380
25 LW-11.7/0.6~10 Twin-col. two-stage 11.7 Inlet 0.06 MPa 1.00 2625×1550×2576 3.00 132 380
26 LW-20/2 Twin-col. single-stage 20 Micro-positive-P 0.20 2150×910×2170 2.00 65 380
27 LW-20/4 Twin-col. two-stage 20 Micro-positive-P 0.40 2730×1550×2432 3.00 110 380
28 LW-20/8 Twin-col. two-stage 20 Micro-positive-P 0.80 2630×1550×2332 3.00 132 380
29 LW-20/18 Twin-col. 3-stage 20 Micro-positive-P 1.80 3500×2600×1850 6.00 240 (250) 380/6K/10K
30 LW-25/3.5 Twin-col. single-stage 25 Micro-positive-P 0.35 2926×1550×2690 3.20 132 380
31 LW-30/2 Twin-col. single-stage 30 Micro-positive-P 0.20 3140×1550×2445 3.40 90 380
32 LW-30/4 Twin-col. two-stage 30 Micro-positive-P 0.40 2990×2370×1550 4.00 132 380
33 LW-34.2/16 Twin-col. two-stage 34.2 Micro-positive-P 1.60 3500×1600×1850 9.00 350 380/6K/10K
34 LW-35/0.3~3.5 Twin-col. two-stage 35 Inlet 0.03 MPa 0.35 2365×1600×2310 4.20 132 380
35 LW-40/2 Twin-col. single-stage 40 Micro-positive-P 0.20 2926×1550×2690 3.20 132 380
36 LW-40/4 Twin-col. two-stage 40 Micro-positive-P 0.40 2360×1655×2548 4.50 160 380
37 LW-50/6 Twin-col. two-stage 50 Micro-positive-P 0.60 2360×1685×2235 6.50 260 380/6K/10K
38 LW-60/2.5 Twin-col. single-stage 60 Micro-positive-P 0.25 3260×1655×2548 5.00 220 380
39 LW-60/4 Twin-col. two-stage 60 Micro-positive-P 0.40 3260×1655×2548 5.00 260 380/6K/10K
40 LW-75/1.5 Twin-col. single-stage 75 Micro-positive-P 0.15 4000×2100×2600 7.80 220 380
41 DW-5/0.08~120 Four-col. four-stage 5 Inlet 0.08 MPa 12.00 5000×4500×2200 6.50 132 380
42 DW-6.8/60 Twin-col. four-stage 6.8 Micro-positive-P 6.00 4850×2500×1000 5.50 160 380
43 DW-8.5/45 Twin-col. four-stage 8.5 Micro-positive-P 4.50 4850×2500×1000 5.50 160 380
44 DW-10/24~36 Twin-col. single-stage 10 Inlet 2.40 MPa 3.60 4900×3300×2500 10.00 355 6K/10K
45 DW-11.5/12 Twin-col. two-stage 11.5 Micro-positive-P 1.20 5200×1700×2200 6.50 132 380
46 DW-15/8 Twin-col. two-stage 15 Micro-positive-P 0.80 5200×1700×2200 6.10 132 380/6K/10K
47 DW-20/8 Twin-col. two-stage 20 Micro-positive-P 0.80 5200×1700×2200 6.50 160 380
48 DW-22/0.4~16 Twin-col. 3-stage 22 Inlet 0.04 MPa 1.60 5000×1450×2400 7.00 280 380/6K/10K
49 DW-27/11~15.8 Twin-col. single-stage 27 Inlet 1.10 MPa 1.58 5100×3700×2520 9.00 315 380/6K/10K
50 DW-27.5/5~8 Twin-col. single-stage 27.5 Inlet 0.50 MPa 0.80 5200×1700×2200 7.00 220 380/6K/10K
51 DW-34.2/16 Twin-col. two-stage 34.2 Micro-positive-P 1.60 5200×1700×2200 9.00 315 3380/6K/10K
52 DW-35/8 Twin-col. two-stage 35 Micro-positive-P 0.80 5200×1700×2200 7.00 250 380/6K/10K
53 DW-35/40 Four-col. four-stage 35 Micro-positive-P 4.00 6200×3300×2500 12.00 500 6K/10K
54 DW-40/2~3.5 Twin-col. single-stage 40 Inlet 0.20 MPa 0.35 4760×2045×2105 5.50 160 380
55 DW-40/8 Twin-col. two-stage 40 Micro-positive-P 0.80 5200×1700×2200 7.50 280 380/6K/10K
56 DW-51.5/6 Twin-col. two-stage 51.5 Micro-positive-P 0.60 4880×3000×2265 6.00 280 380/6K/10K
57 DW-57.5/4.5 Twin-col. two-stage 57.5 Micro-positive-P 0.45 5000×1450×3100 6.00 315 6K/10K
58 DW-60/6 Twin-col. two-stage 60 Micro-positive-P 0.60 5000×1450×3100 7.00 350 6K/10K
59 DW-66/28 Four-col. four-stage 66 Micro-positive-P 2.80 5800×3300×2500 13.00 900 6K/10K
60 DW-68/4 Twin-col. two-stage 68 Micro-positive-P 0.40 5000×1450×3100 7.00 400 6K/10K
61 DW-86/4~12.5 Twin-col. single-stage 86 Inlet 0.40 MPa 1.25 7000×4200×3100 25.00 1400 6K/0K
62 DW-92/5~13 Twin-col. single-stage 92 Inlet 0.50 MPa 1.30 7000×4200×3100 25.00 1500 6K/10K
63 DW-100/8 Twin-col. two-stage 100 Micro-positive-P 0.80 5600×3600×2550 17.00 630 6K/10K

Note: “Micro-positive-P” inlet indicates near-atmospheric micro-positive-pressure inlet design preventing air ingress. Bracketed inlet pressures indicate high-pressure booster configurations where hydrogen is received from an upstream stage or storage vessel. Custom single-unit capacity within 5.5 kW to 2,000 kW available on request for both oil-free hydrogen compressors and hydrogen booster compressors. All 380 V models use explosion-proof motors; models at 6 kV and 10 kV use flame-proof or increased-safety motors.

Why Hydrogen Requires Dedicated Oil-Free Compression Equipment

The Unique Physical and Chemical Properties of Hydrogen

Hydrogen gas presents a combination of properties that make it the most demanding gas to compress safely. Its molecules are the smallest of any gas — approximately 1/14 the molecular weight of air — which means hydrogen permeates through polymer seals, diffuses through metal lattices, and leaks through clearances that are effectively gas-tight for all other gases. Standard air compressor shaft seals and piston ring clearances, designed for air molecules of molecular weight 29, allow substantial hydrogen leakage that creates localised flammable concentrations outside the compressor. Hydrogen also burns with an invisible flame at a very wide flammability range of 4% to 75% in air — a leakage-initiated fire can be undetectable without specific hydrogen leak detection equipment, making seal integrity not merely an efficiency concern but a critical safety requirement.

Hydrogen causes embrittlement of certain carbon and alloy steels at elevated pressure — this hydrogen embrittlement reduces the tensile ductility of the steel, increasing the risk of sudden fracture of pressure-containing components without visible prior deformation. All pressure-containing components in this series — cylinder bodies, valve housings, inter-stage piping, and piston rods — use hydrogen-service-rated materials selected and tested in accordance with Nelson curve criteria for the operating temperature and hydrogen partial pressure of each stage. The oil-free design using PTFE composite piston rings is equally essential: lubricating oil contamination of compressed hydrogen causes fouling of downstream process equipment in chemical synthesis applications and catalyst poisoning in hydroprocessing reactors, and oil vapour in hydrogen creates a combustible aerosol mixture in high-pressure piping that is more hazardous than hydrogen alone.

Hydrogen compressor application scenarios — chlor-alkali electrolysis hydrogen recovery, water electrolysis green hydrogen, refinery hydroprocessing, methanol synthesis, hydrogen fuel cell vehicle FCEV fuelling station, hydrogen energy storage
Hydrogen compressor application scenarios — chlor-alkali electrolysis recovery, water electrolysis green hydrogen production, petroleum refinery hydroprocessing, methanol synthesis, FCEV hydrogen fuelling stations, and hydrogen energy storage

Stage Count Selection — Matching Pressure Ratio to Compression Stages

Because hydrogen has an unusually high isentropic exponent (approximately 1.4, similar to air but with much higher discharge temperature per unit pressure ratio due to the high specific heat ratio of hydrogen at low molecular weight), the discharge temperature rise per compression stage is more severe than for heavier gases at the same pressure ratio. To maintain discharge temperature below safe limits — typically 160 deg C maximum per stage — and to achieve adequate volumetric efficiency at each stage, the compression ratio per stage for hydrogen is limited to approximately 2.5:1 to 3.5:1. This means that to achieve a 30:1 overall pressure ratio (from near-atmospheric to 3.0 MPa), three compression stages are required. For higher pressure ratios to 6.0 MPa or above from atmospheric inlet, four stages are standard. Models with elevated inlet pressure (booster compressors) can achieve the required outlet pressure in fewer stages because the overall pressure ratio from inlet to outlet is lower.

High-Pressure Inlet Booster Models

Several models in this series are booster compressors with elevated inlet pressures — for example the ZW-0.1/21~25 (inlet 2.10 MPa, outlet 2.50 MPa) and LW-4.65/24~35 (inlet 2.40 MPa, outlet 3.50 MPa). These are used where hydrogen arrives from an upstream source already at moderate pressure — such as from a reforming unit, an electrolyser stack at working pressure, or a storage vessel being discharged — and must be boosted to a higher pressure for pipeline injection, cylinder filling, or process feed at higher pressure. Booster compressors have smaller bore-to-stroke ratios reflecting their lower volumetric flow requirement per unit mass throughput at the elevated inlet density of hydrogen, and their shaft seal design must handle the higher inlet pressure without leakage even under transient pressure fluctuations.

5 Core Advantages of This Hydrogen Compressor Series

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Intrinsically Oil-Free — Hydrogen-Grade Purity

PTFE composite piston rings with distance piece isolation between crankcase and compression cylinder deliver hydrogen free of hydrocarbon contamination at every stage. No downstream oil coalescer or activated-carbon stage is needed for oil removal — the hydrogen leaving the compressor contains no lubricating oil by design. This is the mandatory standard for refinery hydroprocessing catalyst protection, ammonia and methanol synthesis catalyst protection, fuel cell vehicle hydrogen purity compliance, and semiconductor hydrogen supply applications.

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Broadest Hydrogen Coverage — 63 Models

From a 7.5 kW small booster compressor for laboratory hydrogen supply to a 1,500 kW large-capacity single-stage booster for refinery hydrogen make-up, 63 standard models cover every industrial hydrogen compression requirement in a single product family. The unified oil-free design philosophy, explosion-proof electrical equipment standard, and hydrogen-service material specification apply across the entire range, simplifying specification and supplier qualification regardless of application scale.

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Hydrogen-Specific Sealing — Zero Leakage Architecture

All shaft seals are designed specifically for hydrogen service — using labyrinth seals with inert purge gas sweep or double mechanical seals with seal gas barrier — to prevent hydrogen leakage regardless of the small molecular diameter. Piston rod packings use hydrogen-service PTFE segmented rings with controlled leakage collection to a safe recovery point. Every sealing interface is verified for hydrogen service at both design pressure and thermal cycling conditions, not just at standard gas service conditions.

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Flexible Inlet Pressure — Booster and From-Atmospheric Designs

The series covers both from-atmospheric (micro-positive-pressure inlet) and booster (elevated inlet pressure) configurations. This allows the correct compressor to be matched to the actual hydrogen source pressure — from electrolysis stacks operating at near-atmospheric through to reformer hydrogen at 2.0 to 2.5 MPa — without oversizing the compressor for a high overall pressure ratio when the hydrogen arrives already partially compressed. Booster models achieve better efficiency and lower equipment cost for high-inlet-pressure hydrogen sources.

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Field-Maintainable with Hydrogen-Service Validated Spares

PTFE piston rings, valve plates and springs in hydrogen-service alloy, piston rod packings, and shaft seals are all field-replaceable items validated for hydrogen service. Maintenance in a hydrogen environment requires hydrogen-specific procedures — purging with inert gas before opening, controlled atmosphere for piston ring replacement to prevent air ingress, and hydrogen leak testing after reassembly before restart. Our application engineers provide model-specific hydrogen service maintenance procedures alongside the standard technical documentation.

Typical Application Scenarios

Chlor-Alkali Electrolysis Hydrogen Recovery

Chlorine-alkali electrolysis plants produce hydrogen as a co-product from the electrolysis of sodium chloride brine. This hydrogen is generated at near-atmospheric pressure, slightly above 0.1 MPa, and must be compressed for either sale as chemical hydrogen, use in on-site HCl synthesis, or pipeline transport to adjacent chemical plant users. Series models in the ZW and LW range with micro-positive-pressure inlet at 0.20 to 1.0 MPa discharge serve chlor-alkali hydrogen recovery stations, with oil-free construction mandatory because lubricant contamination of chlor-alkali hydrogen is unacceptable for downstream chemical process use.

ZW-1.5/8 to LW-20/8 · 1.5–20 m³/min · 0.40–0.80 MPa

Green Hydrogen from Water Electrolysis

Water electrolysis — both alkaline and PEM (proton exchange membrane) — produces hydrogen at near-atmospheric or low pressure (typically 0.1 to 1.0 MPa from PEM stacks). This hydrogen must be compressed for storage in high-pressure vessels (20 to 70 MPa for hydrogen fuel cell vehicle fuelling), pipeline distribution, or chemical feedstock use. The multi-stage models including DW-6.8/60 (four-stage to 6.0 MPa) and DW-5/0.08~120 (four-stage to 12.0 MPa from 0.08 MPa inlet) serve the first stage of high-pressure hydrogen storage compression at green hydrogen production sites, with additional reciprocating or diaphragm boosters for final stage compression to storage pressure.

ZW-3/30 to DW-35/40 · 3–35 m³/min · 3.0–6.0 MPa

Petroleum Refinery Hydroprocessing

Hydrodesulfurisation (HDS), hydrodenitrogenation (HDN), hydrocracking, and catalytic reforming hydrogen recycle circuits all require large volumes of high-purity hydrogen compressed to reactor operating pressures of 1.0 to 6.0 MPa. Hydrogen make-up compressors receive fresh hydrogen from a hydrogen production unit (steam methane reforming or electrolysis) at 1.0 to 2.5 MPa and boost it to reactor pressure. The high-inlet-pressure booster models — DW-27/11~15.8, DW-27.5/5~8, DW-86/4~12.5, DW-92/5~13 — serve refinery hydrogen make-up compression duty with single-stage booster configuration suited to the modest pressure boost ratio required.

DW-27/11 to DW-92/5~13 · 27–92 m³/min · Booster duty

Methanol and Ammonia Synthesis Feed

Methanol synthesis requires hydrogen-CO mixtures at 5.0 to 6.0 MPa reactor inlet pressure. Ammonia synthesis requires hydrogen-nitrogen mixtures at 15 to 30 MPa (with downstream reciprocating synthesis gas compressors for final pressure). The hydrogen feed compression stage — from reformer outlet at 1.0 to 2.5 MPa to synthesis loop pressure — is the primary application for the large LW and DW three-stage and four-stage models. These applications require strict oil-free hydrogen purity to protect synthesis catalysts from deactivation by hydrocarbon contamination, which is irreversible for precious-metal catalysts.

LW-20/18 to DW-66/28 · 20–66 m³/min · 1.80–3.0 MPa

Hydrogen Fuelling Stations for FCEVs

Hydrogen fuel cell vehicle fuelling stations require hydrogen compressed to 35 MPa or 70 MPa for vehicle tank filling. The first compression stage from hydrogen supply pipeline (typically 2 to 5 MPa) or on-site electrolyser (0.5 to 2 MPa) to intermediate storage (20 MPa) is within the range of this reciprocating series. Models with 6 MPa discharge (DW-6.8/60, DW-8.5/45) and four-stage models serve as the primary compressor stage in FCEV station compression trains, with ionic or diaphragm compressors providing the final stage to 70 MPa. Fuelling station hydrogen purity must meet SAE J2719 / ISO 14687 hydrogen quality standards, requiring oil-free compression throughout.

DW-6.8/60, DW-8.5/45, DW-35/40 · 6.0 MPa first stage

Industrial Atmosphere Furnaces and Chemical Hydrogenation

Steel annealing furnaces, copper bright annealing lines, glass polishing furnaces, and powder metallurgy sintering furnaces use hydrogen or hydrogen-nitrogen mixed atmospheres at 0.20 to 1.0 MPa to prevent oxidation and achieve controlled surface chemistry. These applications require a steady low-pressure hydrogen supply at modest flow rates from cylinders or pipeline. The LW-series single-stage models (LW-10/4 to LW-40/4) serve atmosphere furnace hydrogen supply compression. For chemical hydrogenation of edible oils, pharmaceuticals, or petrochemicals, higher purity and higher pressure hydrogen at 0.5 to 3.0 MPa is required from DW two-stage or three-stage models.

LW-10/4 to LW-40/4 · 0.20–0.40 MPa furnace atmosphere supply

How to Specify a Hydrogen Compressor — Key Selection Criteria

1

Define Inlet Pressure and Hydrogen Source

The inlet pressure determines whether you need a from-atmospheric model (micro-positive-pressure inlet) or a booster model (elevated inlet pressure). Chlor-alkali electrolysis and water electrolysis hydrogen arrives near atmospheric pressure. Reformer hydrogen typically arrives at 1.0 to 2.5 MPa. Pipeline hydrogen arrives at supply pipeline pressure. Matching the compressor inlet to the actual source pressure, rather than specifying a from-atmospheric model that then throttles a high-pressure source, is critical for both efficiency and compressor longevity — operating a micro-positive-pressure model on a high-pressure inlet causes severe volumetric overload and discharge temperature problems.

2

Verify Hydrogen Purity Requirements and Impurities

While all models in this series are oil-free, the hydrogen may contain other impurities from the source — moisture from electrolysis, trace oxygen from PEM electrolyser crossover, CO from reformers, or H₂S from coke oven gas hydrogen fractions. These impurities affect material selection for valves, seals, and inter-stage coolers. Moisture requires stainless steel inter-stage coolers and separators. CO at high concentration requires CO-resistant sealing materials. Oxygen traces in hydrogen from PEM electrolysers must be removed before compression to prevent formation of explosive H₂-O₂ mixtures in the compression system. Always provide the full hydrogen composition and impurity analysis to our application engineers before specification.

3

Plan Hydrogen Safety Systems

Hydrogen compressor rooms require dedicated hydrogen leak detection systems — electrochemical or catalytic hydrogen sensors at ceiling level (hydrogen rises rapidly), with alarms at 10% LEL (lower explosive limit) and automatic compressor shutdown at 25% LEL. Emergency ventilation must provide minimum 12 air changes per hour with natural or forced ventilation direct to atmosphere. All electrical equipment must be rated for the hazardous area zone classification. Piping and fittings must use hydrogen-service ratings — standard stainless steel NPT fittings are not acceptable for hydrogen service above 0.7 MPa. Purge sequences with inert gas (nitrogen) for start-up and shutdown must be included in the operating procedure to prevent air-hydrogen mixing in the compression system.

4

Plan Downstream Treatment and Pressure Vessel Codes

Downstream of the compressor, install: inter-stage and final-stage moisture separators with automatic drains; a hydrogen-service high-pressure air receiver or buffer vessel sized for the process; pressure relief valves with discharge to a hydrogen flare or safe outdoor vent (not indoors); and pressure regulators for downstream distribution. All pressure vessels, piping, valves, and fittings in hydrogen service must be designed and certified under the applicable national pressure vessel code (GB150 in China, ASME VIII Div.1 for export to the USA, PED for Europe). Our documentation package for each compressor includes the required design pressure certificate data for vessel code compliance by the project pressure vessel engineer.

Frequently Asked Questions — Hydrogen Compressor

1. Why can hydrogen not be compressed in a standard air or general gas compressor?

Standard compressors fail hydrogen service on several critical points. Shaft seals and piston ring clearances designed for air (molecular weight 29) allow significant hydrogen leakage because hydrogen molecules are 14 times lighter and smaller, permeating clearances that are gas-tight for other gases. Carbon and alloy steels in standard compressors are not rated for hydrogen embrittlement service — at the elevated pressures and temperatures inside a multi-stage hydrogen compressor, hydrogen atoms diffuse into the steel microstructure, reducing ductility and eventually causing brittle fracture of pressure-containing components. Lubricating oil in a standard lubricated compressor contaminates the hydrogen and creates a hydrocarbon aerosol in high-pressure piping that is more dangerous than hydrogen alone. The explosion-proof motor specification of a standard compressor may not be adequate for the Zone 1 hydrogen hazardous area environment created by unavoidable hydrogen micro-leakage around a standard shaft seal.

2. What is the maximum single-stage discharge temperature for hydrogen compression?

The maximum permitted discharge temperature at any stage is 160 deg C. This limit is set by the thermal stability of the PTFE piston rings — PTFE begins to degrade above approximately 200 deg C, producing fluorine-containing decomposition products that contaminate the hydrogen and damage downstream equipment. The 160 deg C limit provides a conservative safety margin. Because hydrogen has a relatively high temperature rise per unit pressure ratio compared with heavier gases, the compression ratio per stage is limited to maintain discharge temperature within this limit. This is why hydrogen compressors above a modest overall pressure ratio require more stages than equivalent air or CO₂ compressors of the same discharge pressure. All models include a discharge temperature high alarm at 140 deg C and automatic shutdown at 160 deg C per stage.

3. How is the compressor purged when starting and stopping?

Hydrogen compressors must never be opened to atmosphere without first purging with inert gas (nitrogen) to remove all hydrogen from the gas path. Before start-up from a maintenance-stopped condition, the compression gas path must be purged with nitrogen to remove all air before hydrogen is admitted — otherwise the compressor gas path contains an explosive hydrogen-air mixture when the first hydrogen enters. The purge sequence is: close inlet and outlet isolation valves, connect nitrogen purge connection, purge all stages to atmospheric pressure with nitrogen, verify oxygen content below 0.5% by analysis, then open hydrogen inlet slowly to displace nitrogen with hydrogen before starting. After a controlled shutdown, the sequence is reversed: close inlet, vent hydrogen to a safe point, purge with nitrogen, then close. These procedures are provided in the compressor operating manual and must be incorporated in the site safe operating procedure.

4. What PTFE ring service life is expected in hydrogen service?

Under good operating conditions — clean dry hydrogen at inlet, cooling water maintained at 25 to 35 deg C, discharge temperature consistently below 140 deg C, and no liquid carry-over from upstream separator failure — PTFE composite piston ring life in hydrogen service is typically 3,000 to 6,000 hours for LP stage rings and 2,000 to 4,000 hours for HP stage rings. The key variables that shorten ring life in hydrogen service are: moisture carry-over from inadequate inter-stage separation (PTFE absorbs water and swells, accelerating wear); particulate contamination from upstream processes; and thermal cycling from frequent start-stop operation. Continuous steady-state hydrogen compression typically achieves longer ring life than intermittent-duty applications. Ring wear is monitored by discharge temperature rise trend and inter-stage pressure deviation from design values.

5. What spare parts and warranty support are provided?

Standard 12-month warranty from commissioning covers manufacturing defects in materials and workmanship. A commissioning spare parts set is strongly recommended — PTFE piston ring sets for all stages, valve plates and springs in hydrogen-service stainless alloy, inter-stage gasket sets in hydrogen-compatible materials, shaft seal spares, and hydrogen leak detection calibration gas. Hydrogen compressor spare parts must be sourced from the original manufacturer or an approved supplier to ensure material specifications for hydrogen embrittlement resistance, PTFE hydrogen compatibility, and seal material permeability ratings are maintained. Using standard industrial spare parts not rated for hydrogen service creates both performance and safety risks. Contact our technical team for model-specific spare parts holding recommendations and annual supply programme options for each installation.

Ready to Specify an Oil-Free Hydrogen Compressor for Your Application?

Our application engineering team provides free hydrogen compressor sizing — including stage count optimisation for your pressure ratio, hydrogen purity specification review, booster versus from-atmospheric configuration recommendation, hydrogen safety system guidance, and complete technical documentation for regulatory approval. Factory-direct pricing, global export, and custom design within 5.5 kW to 2,000 kW.