14 Large-Format Refrigeration Vessels for Maekawa: Expansion Drums, Evaporators, Condensers, and Ethylene Regenerator in 16MnDR/S30408

Lmart manufactured 14 industrial refrigeration pressure vessels for Maekawa Manufacturing Co., Ltd. (the customer製作所) — Japan’s leading industrial refrigeration company. The equipment set includes three 19,746 kg expansion drums at DN2400, a flooded evaporator, condensers, oil separators, an ethylene regenerator in S30408, and storage/reservoir vessels, all built to GB standard in 16MnDR, Q245R, Q345R, S30408, and OCr18Ni9 for ammonia and hydrocarbon refrigeration service.

Customer	Maekawa Manufacturing Co., Ltd. — 株式会社the customer製作所
Industry	Industrial refrigeration — ammonia, ethylene, hydrocarbon refrigerant systems
Country	Japan (OEM) — systems installed in China
Equipment	Expansion drums × 3, flooded evaporator × 1, condensers × 2, oil separators × 2, oil coolers × 2, reservoir × 1, ethylene regenerator × 1, storage drum × 1, oil pot × 1, economizer × 1, dry-type evaporator × 1 (14 units total)
Design Code	GB/T 150
Key Materials	16MnDR, Q245R, Q345R, S30408, OCr18Ni9
Heaviest Unit	Expansion drum — 19,746 kg each, DN2400, 3 units
Service	Ammonia refrigeration, ethylene refrigeration, oil management

Customer Background and Industry Context

Maekawa Manufacturing Co., Ltd. (株式会社the customer製作所), founded in Tokyo in 1924, is Japan’s foremost industrial refrigeration company and one of the world’s leading suppliers of ammonia, CO&sub2;, and hydrocarbon refrigeration systems. With over 5,000 employees and operations in more than 40 countries, Maekawa designs and builds complete refrigeration plants for food processing, cold chain logistics, petrochemical applications, and industrial gas production. Their the customer-branded compressors and packaged refrigeration units are installed in thousands of facilities worldwide.

Industrial refrigeration systems at the scale Maekawa operates involve substantially larger pressure vessels than commercial HVAC equipment. Expansion drums, flooded evaporators, and condensers in ammonia or ethylene service handle large liquid inventories at low temperatures — conditions that require low-temperature impact-tested materials (16MnDR for carbon steel service, S30408 for stainless) and careful attention to brittle fracture prevention. The three expansion drums in this project, each weighing nearly 20 tonnes at DN2400, are among the largest individual vessels in Lmart’s refrigeration reference portfolio.

Maekawa’s vendor qualification process reflects the safety criticality of ammonia refrigeration vessels. Ammonia is toxic and flammable — a vessel failure in a food processing plant can have catastrophic consequences. Maekawa requires not only code compliance but also demonstrated experience with low-temperature materials, large-diameter vessel fabrication, and the specific internal configurations (baffles, distributors, demister pads) that refrigeration vessels require.

Challenges and Engineering Pain Points

Large-Diameter Low-Temperature Vessels: DN2400 Expansion Drums

The three expansion drums represent the project’s most demanding fabrication challenge. At DN2400 (2.4 meters diameter), 25 mm wall thickness, 10,756 mm length, and 19,746 kg each, these are large-format pressure vessels in S30408 stainless steel. The combination of large diameter and stainless construction requires precise shell plate rolling to achieve roundness tolerances, controlled welding to minimize distortion on long longitudinal seams, and PWHT or solution annealing consideration for intergranular corrosion prevention. At nearly 20 tonnes each, handling during fabrication, heat treatment, pressure testing, and transport requires purpose-built fixtures and high-capacity overhead cranes.

Low-Temperature Material Requirements for Refrigeration Service

Ammonia refrigeration systems operate at evaporating temperatures that can reach −40 °C or lower, depending on the application. The primary carbon steel vessels in this project use 16MnDR — a Chinese normalized low-temperature steel equivalent to ASTM A516 Gr.60/65 with guaranteed Charpy V-notch impact values at the minimum design metal temperature (MDMT). Each heat of 16MnDR plate must be impact-tested at the design temperature, and the weld metal and heat-affected zone must meet the same impact requirements through WPQ testing. The ethylene regenerator and expansion drums use S30408 (304 stainless), which has inherent low-temperature toughness but requires attention to sensitization during welding to prevent intergranular corrosion in the process-wetted zones.

Diverse Equipment Types in a Single Order

This project encompasses 14 vessels spanning at least eight distinct equipment types: expansion drums, flooded and dry-type evaporators, shell-and-tube condensers, oil separators with coalescing internals, oil coolers, a refrigerant reservoir, an ethylene regenerator (essentially a heat exchanger operating with ethylene refrigerant), an oil pot, an economizer, and a storage drum. Each type has unique internal configuration requirements — tube bundles for the evaporators and condensers, coalescing media for oil separators, distribution headers for the flooded evaporator, and level control nozzle arrangements for the expansion drums. Engineering and manufacturing all eight types from a single workshop requires broad fabrication capability.

Ethylene Regenerator in S30408

The ethylene regenerator (Item 82) at DN800, 14 mm wall thickness, and 5,475 kg in S30408 operates in ethylene refrigerant service — a cryogenic application where the regenerator recovers cold energy from the returning ethylene vapor to pre-cool the incoming liquid. Ethylene boils at −104 °C at atmospheric pressure, though the regenerator likely operates at elevated pressure with correspondingly higher temperatures. S30408 is appropriate for this cryogenic service, but the tube-to-tubesheet joints and internal baffles must maintain leak-tight integrity across the large temperature differential between the cold ethylene side and the warmer process side.

Why Maekawa Selected Lmart

Large-diameter vessel capability. The three DN2400 expansion drums at nearly 20 tonnes each require rolling, welding, and handling capacity that many mid-size fabricators cannot accommodate. Lmart’s workshop infrastructure — plate rolls, welding positioners, overhead cranes, and heat treatment furnaces — handles vessels in this size range without outsourcing critical production steps.

Low-temperature material experience. Ammonia and ethylene refrigeration vessels demand demonstrated competence with impact-tested materials (16MnDR, S30408) and welding procedures qualified at the MDMT. Lmart’s fabrication history includes extensive work with low-temperature steels and austenitic stainless for refrigeration, LNG, and cryogenic applications.

Multi-type equipment from single source. Rather than sourcing heat exchangers from one vendor, pressure vessels from another, and oil management vessels from a third, Maekawa consolidated all 14 units with Lmart. This ensures consistent material quality, common documentation format, and synchronized delivery scheduling for the complete refrigeration plant equipment set.

Japanese quality expectations. Lmart’s track record with Japanese customers (including Kobe Steel, Toyo Engineering, and others) demonstrates familiarity with the inspection standards, documentation thoroughness, and communication protocols that Japanese OEMs require from their Chinese suppliers.

Engineering and Manufacturing Solution

The 14 vessels were manufactured as a coordinated equipment set supporting a complete industrial refrigeration plant, with each vessel type engineered for its specific role in the refrigeration cycle.

Expansion drums (3 × 19,746 kg). The three expansion drums serve as flash vessels where high-pressure liquid refrigerant expands to a lower pressure, producing a two-phase mixture of liquid and vapor. At DN2400 × 10,756 mm in S30408 with 25 mm walls, these are the largest and heaviest vessels in the project. The internal configuration includes inlet distributors to manage the two-phase flow entry, demister pads or baffles to prevent liquid carryover to the compressor suction, and multiple nozzle connections for liquid level control, pressure relief, and instrumentation. Shell plate rolling for DN2400 in 25 mm S30408 requires careful control of springback and roundness, with fit-up tolerances verified at multiple stations before longitudinal seam welding.

Flooded evaporator. The flooded evaporator (Item 80, DN850, 6,795 kg in 16MnDR) is a shell-and-tube heat exchanger where liquid refrigerant floods the shell side, evaporating as it absorbs heat from the process fluid flowing through the tubes. The “flooded” design maintains the tubes fully submerged in liquid refrigerant for maximum heat transfer efficiency. Internal baffles control shell-side flow distribution, and the vessel design must accommodate the density difference between liquid and vapor phases to prevent compressor liquid slugging.

Ethylene regenerator. The ethylene regenerator (Item 82, DN800, 5,475 kg in S30408) recovers cold energy from returning ethylene vapor to sub-cool incoming liquid ethylene, improving cycle efficiency. S30408 construction is mandatory for ethylene service temperatures. The regenerator’s thermal design balances heat transfer area against pressure drop on both streams, with the tube-side and shell-side operating at different pressures and temperatures typical of regenerative heat exchange.

Condensers. Two condensers (Items 78 and 86) in 16MnDR and Q245R respectively provide the heat rejection function where compressed refrigerant vapor is cooled and condensed. The larger unit (DN600, 3,606 kg) handles the primary ammonia circuit, while the smaller unit (DN550, 1,899 kg in Q245R) serves a secondary or auxiliary circuit.

Oil management vessels. Oil separators (Items 77 and 85), oil coolers (Items 79 and 88), and the oil pot (Item 81) manage lubricating oil that inevitably migrates with the refrigerant through the compressor. Oil separators use coalescing elements or impingement baffles to remove entrained oil from the discharge gas. Oil coolers reject heat from the separated oil before it returns to the compressor. The oil pot collects oil drained from various low points in the refrigeration circuit. These vessels are smaller individually but critical to compressor reliability — inadequate oil separation leads to fouled heat transfer surfaces and reduced system efficiency.

Storage drum and reservoir. The storage drum (Item 84, DN1600, 7,577 kg in S30408) and reservoir (Item 76, DN750, 1,380 kg in 16MnDR) provide refrigerant charge storage for system pump-down during maintenance and seasonal load variation.

Complete Equipment Specifications

#	Equipment	Qty	Weight (kg)	DN (mm)	THK (mm)	Length (mm)	Material
76	Reservoir	1	1,380	750	10	5,445	16MnDR
77	Oil Separator	1	1,140	711	10	1,791	16MnDR / 16MnDII
78	Condenser	1	3,606	600	8	5,368	16MnDR
79	Oil Cooler	1	430	273	8	2,869	16Mn (normalized)
80	Flooded Evaporator	1	6,795	850	12	6,766	16MnDR
81	Oil Pot	1	120	273	8	1,410	16MnDR
82	Ethylene Regenerator	1	5,475	800	14	4,813	S30408
83	Expansion Drum	3	19,746	2,400	25	10,756	S30408
84	Storage Drum	1	7,577	1,600	22	6,000	S30408
85	Oil Separator	1	775	711	10	763	Q245R
86	Condenser	1	1,899	550	8	4,244	Q245R
87	Economizer	1	610	300	8	3,010	Q245R
88	Oil Cooler	1	427	168	7	2,792	OCr18Ni9
89	Dry-Type Evaporator	1	2,505	550	8	5,177	Q345R

Project Execution, Quality Control, and Delivery

The 14 vessels were manufactured with particular attention to low-temperature material compliance and the diverse internal configurations required for each refrigeration equipment type.

Key QC milestones:

• Incoming material: 16MnDR plate and forgings verified for Charpy V-notch impact values at the specified MDMT; S30408 plate verified for intergranular corrosion resistance per GB/T 4334; Q245R and Q345R verified per standard mill certification requirements
• Weld procedure qualification: WPS/PQR packages include impact testing of weld metal and HAZ at MDMT for all 16MnDR and 16MnDII joints; S30408 weld procedures qualified with ferrite content control (4–12 FN) and intergranular corrosion testing
• Shell rolling for DN2400 expansion drums: roundness verified to ≤ 0.5% of diameter at multiple cross-sections; longitudinal and circumferential weld alignment verified before final welding
• Internal component installation: tube bundle fabrication and insertion for evaporators and condensers; coalescing element mounting for oil separators; distribution header installation for flooded evaporator; demister pad fitting for expansion drums
• NDE: 100% RT on longitudinal and circumferential welds for all vessels in low-temperature service; UT on nozzle-to-shell welds; DPT on all stainless steel welds
• Hydrostatic test at 1.25× design pressure per GB/T 150, with each pressure zone (shell-side, tube-side) tested independently on heat exchangers
• Pneumatic leak test where specified by Maekawa for refrigerant-containing circuits
• Final inspection: dimensional survey, surface preparation, preservation for ammonia/ethylene cleanliness, and documentation package per Maekawa specifications

The three DN2400 expansion drums required special transport arrangements due to their 2.4-meter diameter and nearly 11-meter length. Heavy-lift trailers with route surveys and bridge clearance verification were coordinated for overland delivery to the project site.

Results and Business Impact

Fourteen refrigeration vessels covering the complete scope of a large industrial refrigeration plant — from the largest expansion drums to the smallest oil pot — delivered as a matched equipment set. For Maekawa, single-source supply simplifies procurement, ensures consistent documentation, and enables coordinated delivery scheduling aligned with their system assembly timeline.

The three DN2400 expansion drums at 19,746 kg each represent some of the largest refrigeration vessels Lmart has produced. Their successful fabrication in S30408 at this scale demonstrates capability for the heavy, large-diameter stainless vessels that industrial refrigeration OEMs require — a market segment where fabricator size and crane capacity are genuine barriers to entry.

For Lmart, the Maekawa project adds a world-class industrial refrigeration OEM to its Japanese customer portfolio, complementing the company’s existing relationships with Kobe Steel (compressor vessels), Toyo Engineering (petrochemical equipment), and Mitsubishi Electric (specialty vessels). This breadth of Japanese industrial customer references strengthens Lmart’s position as a qualified supplier to Japan’s most demanding equipment manufacturers.

Customer Voice

Maekawa consolidated the complete pressure vessel scope for this refrigeration plant with Lmart — a procurement approach that reflects confidence in Lmart’s ability to handle the range from 120 kg oil pots to 19.7-tonne expansion drums under a single quality system.

“The expansion drums met dimensional tolerances for our skid mounting. Low-temperature impact test results were consistent across all heats of 16MnDR.”

— Maekawa engineering team (paraphrased from project review)

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