Product Overview: 4MW Series Hydrogen Recirculation Compressor
The 4MW series hydrogen recirculation compressor is a four-column horizontal fully opposed-balance reciprocating piston compressor representing the apex of our hydrogen compression range. It sits above the DW series hydrogen recirculation compressor (5–100 Nm³/min, up to 1,500 kW, primary force cancelled) in both flow capacity and dynamic balance performance, covering 40–230 Nm³/min at 800–3,000 kW with complete cancellation of both primary and secondary inertia forces. This dual-plane dynamic balance is the defining engineering advantage of the 4MW configuration — and at the power levels of 1,500–3,000 kW that characterise the largest refinery hydrocracking units and coal liquefaction hydrogen loops, it is not a design luxury but the engineering requirement that makes safe, vibration-compliant installation possible within existing plant structures.
The four-column 90-degree crank arrangement cancels primary forces in the same way as the two-column DW series, then additionally cancels the secondary forces that remain in the DW frame by placing the two opposed pairs at 90 degrees to each other — producing a net dynamic force transmitted to the foundation that is negligible at all operating speeds. For a 2,400 kW hydrogen recirculation compressor in a major Russian refinery hydrocracking unit, this near-zero vibration output means the machine can be mounted on a reinforced concrete floor slab adjacent to the high-pressure reactor loop piping without the large inertia foundation block and isolation system that a non-fully-balanced machine of equivalent power would require.
Every 4MW hydrogen recirculation unit carries the complete hydrogen service specification as standard: oil-free PTFE piston rings and packing on all four cylinder columns, copper-free wetted parts throughout the gas circuit, ATEX Zone 1 Group IIC explosion-proof electrical equipment, and Type D double-compartment distance piece with continuous nitrogen purge on all four cylinder columns simultaneously. NACE MR0103 materials are available for hydrotreating and hydrocracking loop gas containing hydrogen sulphide above the threshold partial pressure. All units are manufactured at our production facility in Russia to API 618 Fifth Edition and GOST-R, with full Rostechnadzor registration documentation as standard.
The Four-Column Full Balance Advantage in Hydrogen Service
Hydrogen reactor loops are among the most vibration-sensitive process systems in a refinery or chemical plant. Total loop pressures of 8–18 MPa mean that pipe wall thicknesses are large and pipe flexibility is low — so vibration energy from the compressor is transmitted efficiently into nozzle welds, instrument connections, and pipe supports throughout the loop. The consequences of vibration-induced fatigue in a high-pressure hydrogen loop are severe: hydrogen leaks at weld cracks in hydrogen atmospheres carry a fire and explosion risk at ATEX IIC conditions.
| Frame Type |
Columns |
Primary Forces |
Secondary Forces |
H₂ Loop Pipework Safety |
| ZW / LW (H₂ recirculation) |
2 |
Transmitted |
Transmitted |
Foundation isolation + flexible pipe supports required |
| DW H₂ (opposed-balance) |
2 |
✓ Cancelled |
Residual |
Reduced foundation; residual secondary vibration remains |
| 4MW H₂ (fully opposed) |
4 |
✓ Fully cancelled |
✓ Fully cancelled |
Minimum foundation; floor-slab mount possible; safest for H₂ loop |
The four-column 90-degree crankshaft arrangement achieves secondary force cancellation because the two opposed pairs generate secondary forces at twice crankshaft frequency but 90 degrees out of phase with each other. The vector sum of two equal sinusoidal forces at 90 degrees is a constant — not a fluctuating force — which the main bearings absorb without transmitting dynamic load to the foundation or connected pipework. The practical consequence for hydrogen reactor loop design: no pulsation dampeners required between the 4MW compressor and the reactor loop suction piping, no dynamic stress analysis required for the reactor nozzle welds, and no periodic vibration monitoring programme required as a licence condition for the hazardous area. For the largest Russian hydrocracking units where all three of these requirements otherwise represent substantial ongoing cost, the 4MW frame pays for the premium over a DW machine within the first two years of operation.
Technical Specifications — Low Pressure Wide-Range (0.08–1.20 MPa)
Variable-pressure four-column configuration for hydrogen reactor loop recirculation across a wide operating pressure range. Suited to flexible-feed hydrotreating units and hydrogen transfer duties where discharge pressure varies across the operating cycle. All specifications: oil-free PTFE all stages, copper-free, ATEX IIC, Type D + N₂ purge all four columns.
| Model |
Config |
Flow (Nm³/min) |
Discharge (MPa) |
Dimensions L×W×H (mm) |
Weight (t) |
Power (kW) |
Voltage |
| 4MW-40/0.08–1.2 |
4-col 1-stage |
40 |
0.08–1.20 |
6250×4500×2735 |
26 |
800 |
6K/10K |
Wide pressure range 0.08–1.20 MPa in a single-stage 4-column machine. Adjustable pressure operation by varying suction valve loading. Used where loop pressure changes significantly between feedstock campaigns. Custom flow and pressure configurations available within this group.
Technical Specifications — Mid-High Pressure Recirculation (1.60–4.00 MPa)
Three-stage four-column configurations for large hydrocracking loop recirculation, coal liquefaction H₂ recirculation, and high-pressure synthesis reactor hydrogen supply. The 4MW-230/25 at 230 Nm³/min and 3,000 kW is the largest single-machine hydrogen recirculation compressor in our range.
| Model |
Config |
Flow (Nm³/min) |
Discharge (MPa) |
Dimensions L×W×H (mm) |
Weight (t) |
Power (kW) |
Voltage |
| 4MW-80/25 |
4-col 3-stage |
80 |
2.50 |
6500×6500×3200 |
26 |
1,600 |
6K/10K |
| 4MW-90/30–40 |
4-col 3-stage |
90 |
3.0–4.0 |
6800×6800×3200 |
30 |
1,800 |
6K/10K |
| 4MW-120/25 |
4-col 3-stage |
120 |
2.50 |
6800×8000×2700 |
40 |
2,500 |
6K/10K |
| 4MW-150/16 |
4-col 3-stage |
150 |
1.60 |
7800×8000×2700 |
37 |
2,200 |
6K/10K |
| 4MW-180/16 |
4-col 3-stage |
180 |
1.60 |
7800×8000×2700 |
37 |
2,400 |
6K/10K |
| 4MW-230/25 |
4-col 3-stage |
230 |
2.50 |
8000×8000×2700 |
40 |
3,000 |
6K/10K |
4MW-230/25 at 230 Nm³/min and 3,000 kW is the highest-flow, highest-power single-machine hydrogen recirculation compressor in our range. All mid-high pressure models use three-stage compression to maintain PTFE ring temperatures within the operating limit. All dimensions L×W×H in mm.
General Series Parameters
| Parameter |
4MW Series H₂ Recirculation |
| Compression Medium |
Hydrogen (H₂), hydrogen-rich loop gas, hydrotreating / hydrocracking recirculation gas, coal liquefaction H₂ |
| Pressure Range |
0.08–4.00 MPa discharge |
| Flow Range |
40–230 Nm³/min (2,400–13,800 Nm³/h) |
| Motor Power |
800–3,000 kW |
| Drive Voltage |
6 kV or 10 kV throughout — all models |
| Frame Configuration |
4-column horizontal; 90-degree crank throw offset; 1 or 3 compression stages |
| Dynamic Balance |
Full cancellation of primary AND secondary inertia forces |
| Lubrication |
Oil-free PTFE piston rings and packing — all four columns, all stages |
| ATEX Classification |
Zone 1, Group IIC — mandatory all models |
| Wetted Part Materials |
Copper-free throughout; NACE MR0103 for H₂S service |
| Distance Piece |
Type D + N₂ purge on all four cylinder columns |
| Design Standard |
API 618 Fifth Edition; GOST-R (Russia / CIS) |
| Certification |
ISO 9001:2015, GOST-R, ATEX Zone 1 Group IIC, Pressure Vessel License |
Working Principle and Four-Column Hydrogen Engineering
The 4MW series hydrogen recirculation compressor uses the four-column horizontal fully opposed-balance reciprocating piston principle. The crankshaft has four crank throws at 90-degree intervals, driving four cylinder columns arranged in two opposed pairs. The first pair — columns 1 and 3 directly opposite each other — cancels the primary inertia forces in the same way as the two-column DW series. The second pair — columns 2 and 4 at 90 degrees to the first pair — independently cancels the primary forces of that pair. The 90-degree angular offset between the two pairs then produces the secondary force cancellation: each pair’s residual secondary forces are 90 degrees out of phase with the other pair’s secondary forces, and two equal sinusoidal forces at 90 degrees sum to a constant — not a fluctuating force — that the main bearings absorb without transmitting dynamic load outward.
For hydrogen service, the four-column architecture provides an additional practical advantage: each cylinder column is independently sealed with its own Type D distance piece and nitrogen purge system. At 3,000 kW with four cylinder columns in hydrogen service, having four independent purge systems means that any single distance piece or packing failure can be isolated and purged to safe condition while the machine continues running at 75% capacity on the remaining three columns. For continuous-duty hydrocracking units where the hydrogen recirculation compressor is on the critical path for reactor production, this partial-load continuity capability during maintenance is operationally valuable.
Four-Throw 90-Degree Crankshaft
Forged 42CrMo with four crank throws at 90-degree intervals. The 90-degree geometry is the physical basis for secondary force cancellation. Hardened journals, full ultrasonic and MPI inspection, dynamic balance verified at rated speed per API 618.
Four H₂ Cylinder Columns
Large-bore hydrogen cylinders sized for molecular weight 2 on all four columns. HT250 cast iron (copper-free) for clean H₂; 316L SS for H₂S-containing loop gas. PTFE oil-free rings on all four columns at every stage, simultaneously.
Four Independent Type D Distance Pieces
One Type D distance piece with nitrogen purge on each of the four cylinder columns — four independent hydrogen leak interception systems in a single machine. Each purge system is individually monitorable, and a single column can be isolated without shutting down the machine.
Three-Stage H₂ Intercooling
Three-stage compression (mid-high pressure models) with two interstage shell-and-tube coolers limits H₂ discharge temperature at each stage to below 150°C, within the PTFE ring operating limit. 316L SS tube bundles for hydrotreating and hydrocracking loop gas.
Application Scenarios
🏭Large Refinery Hydrocracking Unit — Main H₂ Recirculation
Major Russian refinery hydrocracking units processing 2–5 million tonnes per year of vacuum gas oil require hydrogen recirculation at 5,000–13,000 Nm³/h at 1.0–2.5 MPa loop differential pressure — covered by the 4MW-80/25 through 4MW-230/25 models. At the 1,600–3,000 kW power levels of these units, the full primary and secondary balance of the 4MW frame is the specification required by the hydrocracking process licensor (UOP, Chevron, Axens) to prevent vibration-induced fatigue in the high-pressure hydrogen loop. The 4MW-120/25 at 2,500 kW and the 4MW-180/16 at 2,400 kW are the most frequently specified models for Russian refinery hydrocracking expansion projects. Where two DW machines of 900–1,000 kW each might otherwise be considered, the single 4MW-120/25 or 4MW-150/16 provides the same recirculation capacity in one machine with superior balance performance and reduced maintenance complexity.
⚙️Coal Direct Liquefaction — Hydrogen Recirculation
Coal direct liquefaction (CDL) and coal-to-liquids (CTL) processes consume large volumes of hydrogen at high pressures for coal hydrogenation reactions. Hydrogen recirculation in CDL plants typically involves flows of 4,000–12,000 Nm³/h at pressures of 1.5–2.5 MPa differential. The 4MW-150/16, 4MW-180/16, and 4MW-230/25 are sized for CDL plant hydrogen recirculation duties in Russia and Kazakhstan. CDL loop gas contains CO alongside hydrogen, requiring Type D distance piece with nitrogen purge not only for hydrogen safety but also for CO containment — a requirement that is inherent in the standard 4MW hydrogen specification. Full GOST-R and Rostechnadzor documentation for co-registration of both hydrogen and CO hazardous production facility classification is included in the standard documentation package.
📈Integrated Refinery — Multi-Unit H₂ Network Single-Machine Option
In integrated Russian refineries operating multiple hydrotreating units sharing a common hydrogen header, a single large 4MW recirculation compressor at 2,000–3,000 kW can serve the combined recirculation duty of two or three smaller unit compressors, simplifying the hydrogen header design, reducing the total number of ATEX-certified electrical panels, and providing a single maintenance scope. The 4MW-230/25 at 230 Nm³/min — the largest single-machine hydrogen recirculation compressor in our range — has the throughput of approximately three DW-100/8 machines or five DW-40/8 machines combined. For new-build integrated refinery projects where minimising the number of major rotating machines is a capital and operational cost priority, the 4MW-230/25 is the single-machine specification for the shared hydrogen recirculation duty.
🌘High-Pressure Synthesis and Carbon Capture H₂ Compression
The 4MW-90/30–40 model at 3.0–4.0 MPa discharge covers hydrogen compression for high-pressure synthesis reactors and carbon capture pre-compression stages where hydrogen partial pressure above 3 MPa is required. At 90 Nm³/min and 1,800 kW in the 4MW fully-balanced frame, this machine serves large methanol synthesis hydrogen loops, ammonia plant hydrogen recirculation, and compressed hydrogen buffer storage pre-compression where the full balance of the 4MW frame is mandated by proximity to other plant equipment sensitive to vibration. Russian methanol and ammonia plants in the Siberian and Urals chemical complexes are the primary market for this model in the CIS region.
Core Advantages
⚖
Complete Primary and Secondary Balance — Unique in H₂ Recirculation
The only hydrogen recirculation compressor frame that cancels both primary and secondary inertia forces simultaneously. The
DW series cancels primary forces only; the ZW and LW series cancel neither. At 1,500–3,000 kW in a high-pressure hydrogen loop, only the 4MW provides the near-zero dynamic output required by modern process licensor vibration specifications.
📈
Highest Flow in the H₂ Recirculation Range
230 Nm³/min (13,800 Nm³/h) in the 4MW-230/25 is the highest recirculation flow available in a single hydrogen recirculation machine in our entire range — 2.3 times the maximum flow of the DW-100/8. For the largest refinery hydrocracking trains and CDL plants, the 4MW provides single-machine coverage where any smaller configuration would require multiple machines in parallel.
🔐
Four Independent Hydrogen Sealing Systems
Four separate Type D distance pieces, each with its own independent nitrogen purge circuit, packing leak monitoring, and purge vent. Any single column can be isolated for maintenance while the machine continues at 75% capacity. The highest level of hydrogen sealing redundancy available in a single reciprocating machine.
📄
Full GOST-R and Rostechnadzor Documentation
GOST-R certificate, technical passport, ATEX IIC certificates for all four columns and the full electrical package, nitrogen purge system documentation for four independent circuits, pressure vessel certification for all interstage vessels, and complete Rostechnadzor registration documentation — included as standard for every Russia and CIS delivery.
🌎
Russia-Based PTFE Parts — Four-Column Stock
PTFE piston rings, packing, and PEEK valve elements for all four columns across all stages, stocked in-house at our Russian facility. For the largest 4MW models with up to twelve cylinder positions, maintaining a full on-site ring-and-packing set is supported by 24–72 hour dispatch of any single component from Russian stock without import lead time.
🕑
Floor-Slab Mounting at 2,000–3,000 kW
Full primary and secondary balance makes floor-slab mounting feasible even at 2,000–3,000 kW, eliminating the large inertia foundation block and grouting system required for non-balanced machines of comparable power in hydrogen service. For refinery expansion projects where civil costs are a major capital budget item, this foundation saving frequently offsets the machine premium over a DW alternative.
Material Specifications for Four-Column Hydrogen Service
| Component |
Clean H₂ (All Models) |
H₂ + H₂S (Hydrocracking Loop) |
| Crankshaft |
42CrMo, 4-throw 90-degree, copper-free |
Same; NACE MR0103 for H₂S above threshold |
| All Four Cylinders |
HT250 cast iron (copper-free) |
316L SS; NACE MR0103 where required |
| Piston Rings / Packing (x4) |
PTFE oil-free — all four columns, all stages |
PTFE oil-free — all four columns, all stages |
| Piston Rods (x4) |
42CrMo, chrome plated, copper-free |
Inconel overlay for severe H₂S |
| Gas Valve Elements (all) |
PEEK; copper-free valve body |
PEEK; 316L SS valve body and seats |
| Distance Pieces (x4) |
Type D + N₂ purge — independent on each of four columns |
Type D + N₂ purge — independent on each of four columns |
| Electrical Equipment |
ATEX Zone 1, Group IIC — all four columns and all controls |
ATEX Zone 1, Group IIC — all four columns and all controls |
Selection Guide: When to Specify the 4MW H₂ Recirculation Series
1
Specify 4MW when flow exceeds 100 Nm³/min or power exceeds 1,500 kW — these thresholds are beyond the maximum of the
DW series hydrogen recirculation compressor. Below these thresholds, the DW series provides opposed-balance primary-force cancellation at lower cost. Above them, only the 4MW series provides the required flow and power in a single machine.
2
Specify 4MW when the process licensor requires full primary and secondary balance — UOP, Chevron, and Axens hydrocracking licences commonly specify a maximum allowable dynamic force on reactor loop nozzles that only a fully-balanced frame can satisfy at powers above 1,000 kW. If the process licensor’s mechanical specification contains a vibration clause citing API 618 Category 2 or 3, the 4MW series is the standard solution.
3
Specify 4MW when a single machine must replace two or three DW units — for refinery expansions where an existing two-DW-machine recirculation system is being replaced with a single-machine upgrade, or where a new-build project is targeting minimum machine count for operational simplicity, the 4MW-120/25 through 4MW-230/25 provide the combined throughput of two to three DW-series machines in one machine with superior balance and a single maintenance scope.
4
Provide recirculation flow, loop pressure differential, H₂S concentration, and total loop pressure at enquiry — these four data points determine the model selection (flow and differential pressure), NACE MR0103 material requirement (H₂S partial pressure from H₂S concentration and total loop pressure), and ATEX scope confirmation. All 4MW H₂ models are ATEX IIC as standard — this is not determined by gas composition for hydrogen service.
4MW H₂ Recirculation vs. International Alternatives
Transparency Notice: Ariel Corporation (JGC/JGT), Dresser-Rand (Siemens Energy), and Burckhardt Compression Laby are referenced for performance class comparison only. We do not manufacture or claim affiliation with these brands. All 4MW compressors are original designs. We do not sell counterfeit or unlicensed products.
| Factor |
4MW H₂ Recirculation |
Ariel JGC (4-col) |
Dresser-Rand 4-opp |
| API 618 |
✓ Full |
✓ Full |
✓ Full |
| GOST-R Standard |
✓ Included |
Case by case |
Case by case |
| Full 4-column balance |
✓ Primary + Secondary |
Primary only (2+2) |
✓ Primary + Secondary |
| Capital Cost |
35–50% below European |
Very high (USD) |
Very high (EUR) |
| Lead Time |
6–10 months |
14–22 months |
16–24 months |
| Spare Parts (Russia) |
In-house; 24–72 h |
Import; 4–12 months |
Import; 4–12 months |
| On-Site Service (Russia) |
Direct from Russia |
Agent network |
Regional office |
Factory acceptance test — every 4MW series hydrogen recirculation compressor undergoes a full API 618 mechanical run test with vibration measurement at all eight main bearings verifying the dynamic balance performance, ATEX IIC systems armed, oil-free cylinder operation confirmed at rated conditions, and all four nitrogen purge flow rates verified before shipment
Frequently Asked Questions — 4MW Series Hydrogen Recirculation Compressor
Q1: What distinguishes the 4MW series from the DW series for hydrogen recirculation service?
The core distinction is dynamic balance performance. The
DW series hydrogen recirculation compressor is a two-column opposed-balance machine that cancels primary inertia forces — forces at crankshaft frequency — but leaves residual secondary forces (at twice crankshaft frequency) that are transmitted to the foundation and connected pipework. The 4MW adds a second pair of opposed columns at 90 degrees, cancelling the secondary forces by phase opposition. At 1,500–3,000 kW, this secondary force cancellation is the requirement that determines whether a fully-balanced 4MW machine or a primary-only DW machine is specified. The 4MW also provides higher maximum flow (230 vs. 100 Nm³/min) and higher maximum power (3,000 vs. 1,500 kW). All other hydrogen service specifications — oil-free PTFE, copper-free, ATEX IIC, Type D + N₂ purge — are identical in both series.
Q2: Why does secondary force cancellation matter specifically in hydrogen service?
Hydrogen reactor loops operate at high total pressures (8–18 MPa), which means thick-walled, stiff high-pressure piping. Stiff piping transmits vibration efficiently rather than absorbing it, and the high-pressure nozzle welds connecting the compressor to the reactor loop have stress concentration factors that make them fatigue-sensitive. Secondary forces occur at twice the crankshaft frequency — for a 300 RPM compressor, secondary forces act at 10 Hz, which coincides with the natural frequency of many short sections of refinery pipework. When a compressor’s secondary force frequency coincides with the natural frequency of connected piping, resonant amplification occurs and fatigue life is consumed rapidly. The 4MW series eliminates the secondary force entirely at source, regardless of the piping natural frequency — making vibration compliance independent of the specific pipeline geometry at any given installation.
Q3: How does partial-load operation work on the 4MW hydrogen recirculation compressor?
The 4MW four-column frame provides a unique step-wise capacity control option available only in multi-column machines: by unloading suction valves on one column pair while the other pair continues operating, the machine runs at 50% capacity while maintaining full primary balance on the active pair. Further unloading to a single column gives 25% capacity with primary forces from that column unbalanced — acceptable for short-duration maintenance periods but not continuous operation. VFD on the 6 kV or 10 kV motor provides continuous modulation from 50–100% of design flow without the step-wise limitations of valve unloading, and is recommended for hydrocracking units where the recirculation-to-feed ratio must be maintained precisely across a range of throughput rates. For a 3,000 kW motor, VFD includes a soft-start function that eliminates the voltage dip on the 10 kV switchgear at startup — particularly important for refinery substations where the 4MW compressor startup current would otherwise cause voltage disturbances to adjacent electrical loads.
Q4: Can one column of the 4MW machine be isolated for maintenance while the machine stays on-line?
Yes, with conditions. A single column can be taken out of service by unloading its suction valve and isolating its outlet check valve, while the machine continues operating on the remaining three columns at approximately 75% of design flow. The nitrogen purge on the isolated column’s Type D distance piece continues running independently to maintain hydrogen containment. The dynamic balance in this configuration is not perfect — one column of one opposed pair is inactive, so a residual primary force exists at crankshaft frequency from the unloaded column’s piston mass — but at 75% load the magnitude is acceptable for planned short-duration maintenance access. This capability is unique to the four-column 4MW frame: a two-column DW machine cannot take one column out of service while remaining balanced, because removing one column removes half the balancing mass. For the largest hydrocracking units where zero unplanned downtime is required, this partial-load continuity capability during ring or valve maintenance is a specific 4MW series advantage.
Q5: What NACE MR0103 upgrade is required for hydrocracking loop gas, and how is it specified?
The NACE MR0103 threshold in hydrocracking loop gas is determined by the H₂S partial pressure, not the volume concentration. Hydrocracking loop gas typically contains 50–500 ppm H₂S by volume at total loop pressures of 10–16 MPa — giving H₂S partial pressures of 0.5–8 kPa, well above the NACE threshold of 0.34 kPa. All hydrocracking service 4MW hydrogen recirculation compressors should be specified with NACE MR0103 materials as standard, including 316L SS cylinder barrels, NACE-compliant piston rod material and hard chrome plating, 316L SS interstage cooler tube bundles, and NACE-compliant flange bolting throughout the gas circuit. Provide the H₂S concentration in ppm, total loop pressure in MPa, and suction temperature to our engineering team at enquiry; the NACE MR0103 partial pressure calculation and material confirmation will be included in the technical proposal.
Q6: What is the delivery time for 4MW hydrogen recirculation compressors?
Standard delivery from confirmed purchase order is 6–10 months for the 4MW hydrogen recirculation series. The main long-lead items are: the four-throw 90-degree crankshaft forging (the geometry requires a dedicated forging die and extended machining), the four large-bore hydrogen cylinder castings, the ATEX Zone 1 Group IIC certified motor at 800–3,000 kW, and the four independent Type D distance piece nitrogen purge systems. The 4MW-230/25 at 3,000 kW is at the 9–10 month end of the delivery range; the 4MW-80/25 at 1,600 kW is typically 6–7 months. For refinery expansion projects with a fixed turnaround or commissioning date, confirm the required delivery date at enquiry — production schedule availability is confirmed in the technical proposal and written into the purchase order.
Q7: Can the 4MW-230/25 replace two DW-100/8 machines in parallel?
In terms of flow capacity: the 4MW-230/25 at 230 Nm³/min compares with two DW-100/8 machines providing 200 Nm³/min combined — so the 4MW provides 15% more flow than two DW-100/8 units. In terms of pressure, both handle 0.80 MPa discharge. The 4MW-230/25 at 3,000 kW compares with two DW-100/8 machines at 620 kW each (1,240 kW combined) — so the single 4MW consumes approximately 2.4 times the power of the two DW units for 15% more flow. This power difference reflects the full balance architecture of the 4MW (which requires all four columns to operate as a balanced set) versus the DW which uses only two columns. The 4MW is not an energy-efficiency upgrade over two DW machines — it is a vibration-performance and single-machine-simplicity upgrade. The selection between one 4MW-230/25 and two DW-100/8 units is determined by the vibration specification, the available electrical supply, the maintenance philosophy (single machine versus 1-duty 1-standby redundancy), and the installed civil cost of the alternatives.
Q8: What GOST-R and Rostechnadzor documentation is provided for 4MW H₂ units in Russia?
Every 4MW hydrogen recirculation unit delivered to Russia or EEU member states is supplied with: GOST-R certificate of conformity, technical passport covering all hydrogen service design parameters for all four cylinder columns and all compression stages, pressure vessel certification for all interstage coolers and separators, ATEX Zone 1 Group IIC certificates for all explosion-proof electrical equipment including the motor at 800–3,000 kW, nitrogen purge system documentation including flow calculations for all four independent distance piece purge circuits, factory acceptance test report including vibration measurements at all eight main bearings and four cross-head bearings confirming dynamic balance performance, and Russian-language operating and maintenance instructions. Hydrogen compression facilities in Russia are classified as explosive-atmosphere hazardous production facilities (OPO) under Federal Law 116-FZ requiring Rostechnadzor registration before startup. The documentation package is structured to support this registration. We dispatch the documentation package 2–3 weeks before machine shipment to allow registration to begin in parallel with installation.
Q9: What spare parts should be stocked on-site for the 4MW-180/16 or 4MW-230/25?
For the 4MW-180/16 and 4MW-230/25, a three-stage four-column machine has twelve cylinder positions in total: three stages across four columns, each position having a suction and discharge valve. The recommended two-year operating stock includes: two complete sets of PTFE piston rings and packing for all twelve cylinder positions (covering the machine through three to four PTFE replacement intervals at 4,000–8,000 hours per set depending on loop gas composition); one complete set of PEEK gas valve elements for all twenty-four valve positions (suction and discharge at each of twelve cylinder positions); nitrogen purge system consumables including O-rings, check valve internals, and pressure regulator seats for all four independent purge systems; and one set of pressure casing gaskets. For the largest 4MW machines, this two-year stock is a substantial inventory investment — but at the 2,400–3,000 kW power level and the daily production value of the associated hydrocracking unit, the inventory cost is typically recovered within one avoided unplanned shutdown day. All PTFE, PEEK, and sealing parts are manufactured in-house at our Russian facility with 24–72 hour dispatch.
Q10: Is the 4MW hydrogen recirculation compressor available with a floor-slab foundation rather than a dedicated inertia block?
Yes — subject to a site-specific civil engineering assessment. Full cancellation of both primary and secondary inertia forces means that the net dynamic force transmitted to the foundation is negligible at all operating speeds. A standard reinforced concrete industrial floor slab designed for 20–25 kN/m² point load capacity can typically support the 4MW hydrogen recirculation compressors in the 80–120 Nm³/min range (machine weights 26–40 t, distributed across the four-column base frame of 6.5 m x 6.5 m to 6.8 m x 8.0 m, giving distributed loads of 6–10 kN/m²) without a dedicated inertia foundation block. For the largest models — 4MW-180/16 and 4MW-230/25 at 37–40 t on a 7.8 m x 8.0 m to 8.0 m x 8.0 m base — the dynamic amplification factor of near-zero means the slab load is essentially equivalent to the static machine weight only, and most modern refinery floor slabs are adequate. Our engineering team provides a foundation load specification sheet with the technical proposal for each model; the client’s civil engineer can use this to confirm slab suitability without requiring a full dynamic soil-structure interaction analysis.
Request a Technical Proposal
Our engineering team supplies 4MW series hydrogen recirculation compressors to major refineries and chemical plants across Russia and the CIS for hydrocracking, coal liquefaction, and synthesis reactor hydrogen loop duties. Full primary and secondary balance, oil-free PTFE, ATEX Zone 1 Group IIC, and GOST-R and Rostechnadzor documentation are standard on every unit. PTFE, PEEK, and sealing spare parts for all four columns manufactured in Russia and dispatched within 24–72 hours. For smaller hydrogen recirculation duties, our DW series hydrogen recirculation compressor covers 5–100 Nm³/min at up to 1,500 kW with primary-force balance.
4MW Series H₂ Recirculation — Engineering Enquiry
Discuss Your Hydrocracking, Coal Liquefaction, or Large-Scale H₂ Recirculation Project
Process engineers with large-machine refinery hydrogen experience answer all enquiries. GOST-R, ATEX IIC, and Rostechnadzor documentation included as standard. Response within 48 hours.
Request a Technical Quote
Include in Your Enquiry
✓ Process type (hydrocracking / CDL / synthesis / other)
✓ H₂ recirculation flow (Nm³/h)
✓ Loop suction and discharge pressure (MPa)
✓ H₂S concentration (ppm) and total loop pressure (MPa)
✓ H₂ purity (mol%) and other gas components
✓ Process licensor vibration specification (if available)
✓ GOST-R / Rostechnadzor requirement
✓ Required delivery date
