19 Propylene Refrigeration Compressor Packages for LGE: ABS-Classed Skid Assemblies for Next-Generation VLEC and ULEC Gas Carriers

Lmart fabricated 19 propylene refrigeration compressor packages across three project batches for LGE — a leading compressor and refrigeration system integrator serving the marine gas carrier sector. All units are ABS-classed and destined for Very Large Ethane Carriers (VLECs) and Ultra Large Ethylene Carriers (ULECs) under construction at Jiangnan Shipyard, representing some of the largest ethane and ethylene carriers being built globally.

Customer	LGE — compressor & refrigeration system integrator for marine gas carriers
Industry	Marine gas transportation — VLEC / ULEC newbuilding programs
Shipyard	Jiangnan Shipyard (H-prefix hull numbers)
Equipment	Propylene Refrigeration Compressor Packages — 19 units across 3 batches
Classification	ABS (American Bureau of Shipping)
Vessel Types	VLEC (Very Large Ethane Carrier), 99K VLEC, 150K ULEC (Ultra Large Ethylene Carrier)
Hull Numbers	H2747/48/77/78/79/80, H2823/25/27/28/29/30/31, H2842–H2847
Delivery Period	2024–2025

Customer Background and Industry Context

LGE is a specialist integrator of compressor and refrigeration systems for the marine gas carrier industry. Their scope encompasses the complete refrigeration loop — from compressor selection and package engineering through skid fabrication, piping, instrumentation, and commissioning support — delivered as turnkey packages ready for installation aboard gas carriers during newbuilding.

The equipment in this project serves a new generation of ethane and ethylene carriers being built at Jiangnan Shipyard in Shanghai. Ethane and ethylene are transported as refrigerated liquefied gases at approximately −89 °C (ethane) and −104 °C (ethylene) — temperatures that demand continuous, high-capacity refrigeration to maintain cargo conditions during ocean transit. The refrigeration medium is propylene (R-1270), chosen for its thermodynamic properties in the temperature range required for ethane/ethylene reliquefaction and cargo tank pressure management.

The VLEC (Very Large Ethane Carrier) class represents the current frontier in gas carrier design. The 99K VLEC hulls in Batch 2 carry approximately 99,000 m³ of ethane cargo, while the 150K ULEC (Ultra Large Ethylene Carrier) hulls in Batch 3 push capacity to 150,000 m³ — among the largest dedicated ethylene carriers ever contracted. These vessel sizes drive correspondingly large refrigeration plant requirements: each ship requires multiple compressor packages operating in parallel to handle the thermal load from cargo boil-off and tank cool-down operations.

Challenges and Engineering Pain Points

Structural Integrity Under Marine Dynamic Loading

A refrigeration compressor package aboard a gas carrier is not a stationary industrial installation. The skid frame must withstand ship motions — roll, pitch, heave, and slamming loads — while keeping a large reciprocating compressor, its driver, and all connected piping within alignment tolerances. ABS classification rules require the skid structural design to account for combined static and dynamic loads including 0.5 g vertical acceleration and lateral forces from rolling up to 30°. Every welded connection on the base frame, every pipe support, and every instrument bracket must be designed and inspected against these load cases. Finite element analysis of the skid frame is standard practice, with ABS review of the structural calculations before fabrication begins.

Piping System Design for Propylene Refrigerant Service

Propylene service at cryogenic suction temperatures and high-pressure discharge imposes strict requirements on piping materials, weld procedures, and system cleanliness. Suction-side piping operates at low pressure but sub-zero temperatures, requiring impact-tested materials and stress analysis for thermal contraction from ambient to operating temperature. Discharge-side piping handles high-pressure, high-temperature propylene gas with pulsation effects from the reciprocating compressor. The piping layout must accommodate thermal expansion/contraction across a wide temperature range, compressor nozzle load limitations, and maintenance access requirements — all within the compact envelope of a shipboard machinery room.

Multi-Batch Consistency Across 19 Units

Delivering 19 compressor packages in three batches over two years to a single classification standard requires manufacturing consistency that goes beyond individual unit quality. Each package must be dimensionally interchangeable within its batch — piping connection points, foundation bolt patterns, electrical junction box positions, and instrument locations must match the shipyard’s installation drawings exactly. Any deviation on a single unit creates costly rework at the shipyard. This demands controlled fabrication procedures, standardized tooling and fixtures, and rigorous dimensional verification at each stage of assembly.

ABS Classification Compliance for Gas Carrier Machinery

ABS classification for refrigeration equipment on gas carriers falls under the ABS Rules for Building and Classing Marine Vessels and the IGC Code (International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk). The classification scope covers structural design of the skid frame, pressure-containing components (piping, fittings, valves), welding procedure qualification, welder certification, NDE requirements, hydrostatic/pneumatic testing, and material traceability. ABS surveyors witness critical fabrication milestones including welding procedure qualification tests, radiographic examination of pressure welds, and final hydrostatic/pneumatic tests. The documentation package for each unit runs to hundreds of pages — material certificates, WPS/PQR records, NDE reports, test certificates, and as-built drawings — all requiring ABS review and endorsement.

Why LGE Selected Lmart

Proven skid fabrication capacity for marine gas carrier equipment. Lmart’s reference list includes skid assemblies for Wärtsilä, TGE, Høglund, and Burckhardt — the major system integrators in the LNG/LPG/LEG carrier segment. This track record demonstrates the specific combination of structural fabrication, high-integrity piping, and classification society documentation that marine skid work requires.

Classification society approvals. Lmart holds manufacturing approvals from six classification societies including ABS, DNV, BV, CCS, LR, and NK. For LGE, the existing ABS approval eliminated the qualification lead time that would be required with a new supplier — critical when the first batch of six packages had to align with Jiangnan Shipyard’s hull delivery schedule.

Volume capacity for multi-batch programs. Nineteen compressor packages across three batches requires a fabricator with sufficient workshop space, welding capacity, and project management depth to handle overlapping production runs. Lmart’s 38,000\ m\² workshop and 300+ staff provide the throughput needed without compromising quality on concurrent orders.

Geographic proximity to Jiangnan Shipyard. Lmart’s Zhangjiagang facility is within trucking distance of Jiangnan Shipyard in Shanghai, simplifying delivery logistics for oversized skid assemblies and enabling LGE’s engineers and ABS surveyors to conduct witness inspections without long-distance travel.

Engineering and Manufacturing Solution

Each propylene refrigeration compressor package is a self-contained skid assembly that arrives at the shipyard ready for crane-lift into the vessel’s machinery room, connection to ship systems, and commissioning. Lmart’s scope covers the complete mechanical assembly — everything except the compressor unit itself, which is furnished by the compressor OEM and installed onto Lmart’s skid frame during final assembly.

Skid Frame Structural Fabrication

The base frame is fabricated from structural steel sections designed to ABS requirements for marine machinery foundations. The frame must distribute the compressor’s static weight (typically 5–15 tonnes for a marine refrigeration compressor) plus dynamic loads from reciprocating forces, ship motions, and seismic-equivalent accelerations defined by ABS rules. Key design features include:

• Foundation rails machined to flatness tolerances of ≤ 0.1 mm/m for compressor alignment
• Chock mounting pads positioned to match shipyard foundation bolt patterns
• Lifting lugs designed and proof-load tested per ABS requirements
• Anti-vibration mounting provisions where specified by the compressor OEM
• Drain collection trays integrated into the frame structure

Piping Fabrication and Assembly

The piping system on each package includes suction piping (low-pressure, low-temperature propylene vapor), discharge piping (high-pressure, high-temperature propylene vapor), oil system piping, cooling water piping, and instrument tubing. All pressure piping is fabricated to ABS-approved welding procedures with radiographic or ultrasonic examination of butt welds. Key engineering considerations:

• Material selection: low-temperature carbon steel or stainless steel for suction-side components, with Charpy impact testing per ABS rules at the minimum design temperature
• Pipe stress analysis accounting for thermal expansion from cryogenic suction to hot discharge, with spring hangers and expansion loops where required
• Compressor nozzle load verification — piping reactions at compressor flanges must remain within OEM-specified limits to prevent bearing damage and misalignment
• System cleanliness: all piping internally cleaned, pickled (stainless), and sealed after hydrostatic test to prevent contamination of the refrigeration circuit

Instrumentation and Local Control Panel

Each package includes field-mounted instrumentation — pressure transmitters, temperature sensors, vibration monitors, flow switches, and safety relief valves — along with a local control panel (LCP) or junction box for interface with the ship’s integrated automation system. All instrument tubing is bent and fitted on the skid, with labeled terminations at the junction box for plug-and-play connection during shipyard installation.

Batch-Specific Configurations

Batch	Year	Vessel Type	Qty	Hull Numbers	Classification
1	2024	VLEC	6	H2747, H2748, H2777, H2778, H2779, H2780	ABS
2	2025	99K VLEC	7	H2823, H2825, H2827, H2828, H2829, H2830, H2831	ABS
3	2025	150K ULEC	6	H2842, H2843, H2844, H2845, H2846, H2847	ABS

The three batches reflect the evolution of the VLEC/ULEC newbuilding program. Batch 1 covers the initial VLEC hulls. Batch 2 scales to the 99K VLEC variant with seven units — the additional package accounts for the increased cargo capacity and corresponding higher refrigeration demand. Batch 3 represents the 150K ULEC program — a step-change in vessel size that positions these ships among the largest ethylene carriers afloat. While the fundamental package architecture remains consistent across all three batches, each variant incorporates design refinements driven by the specific cargo system configuration and refrigeration duty of the target vessel class.

Project Execution, Quality Control, and Delivery

Production was organized in batch sequences aligned with Jiangnan Shipyard’s hull construction schedule. Each batch followed a standardized manufacturing workflow with ABS witness points at critical milestones:

• Material procurement and incoming inspection: mill certificates verified against ABS-approved material specifications, PMI on alloy components, Charpy impact test certificates for low-temperature piping materials
• Skid frame fabrication: cutting, fitting, welding of structural sections with dimensional survey after welding and stress relief where required
• Piping prefabrication: spool fabrication per isometric drawings, NDE of pressure welds (RT or UT per ABS rules), fit-up verification
• Skid assembly: compressor mounting on machined rails, piping installation, instrument mounting, electrical cable routing
• Compressor alignment: laser alignment verification of compressor-to-driver coupling with results recorded for ABS review
• Hydrostatic/pneumatic testing: each pressure circuit tested independently — suction system, discharge system, oil system, cooling water system — with ABS surveyor witness
• Final inspection: dimensional survey against shipyard installation drawings, surface treatment/painting verification, cleanliness check, preservation for transport
• Documentation package: compiled and submitted to ABS for review and endorsement — material certificates, WPS/PQR, NDE reports, test records, as-built drawings, equipment data sheets

Completed packages were transported from Lmart’s Zhangjiagang workshop to Jiangnan Shipyard via flatbed truck, with skid dimensions and weights within standard road transport limits. Delivery scheduling was coordinated with LGE and the shipyard to align with hull outfitting sequences — packages arriving too early consume valuable laydown space at the shipyard, while late delivery disrupts the outfitting critical path.

Results and Business Impact

Nineteen propylene refrigeration compressor packages were delivered across three production batches, supporting the construction of 19 next-generation gas carriers at Jiangnan Shipyard. The program spans both VLEC and ULEC vessel classes — representing the full range of large ethane/ethylene carrier newbuilding activity in China.

The progression from Batch 1 (6 units) to Batch 2 (7 units) and Batch 3 (6 units) demonstrates the repeat-order confidence that defines a successful skid fabrication partnership. LGE’s decision to source all three batches from Lmart reflects consistent delivery performance, classification compliance, and manufacturing quality across the initial campaign.

For Lmart, this program establishes a reference in propylene refrigeration compressor packages for the VLEC/ULEC segment — complementing its existing track record in reliquefaction units, BOG compressor skids, CIP units, and bunkering skids for the broader gas carrier market. The 19-unit volume also validates Lmart’s production capacity for sustained multi-batch programs alongside concurrent orders for other system integrators.

Customer Voice

LGE awarded all three batches — 19 propylene refrigeration compressor packages over two years — to Lmart without competitive re-tendering for Batches 2 and 3. This procurement pattern is the strongest endorsement a fabrication partner can receive in the marine equipment supply chain, where system integrators maintain approved vendor lists and actively benchmark alternatives.

“Dimensional consistency across units was critical — every package had to drop into the shipyard’s installation envelope without field modification. Lmart delivered that consistency across all three batches.”

— LGE project engineering team (paraphrased from project review)

Note: Lmart respects client confidentiality. Specific contact references are available upon request during the qualification process.