~60 Snubbers, Separators, Intercoolers, Volume Bottles, and Surge Drums for Kobe Steel: Multi-Code Compressor Ancillary Vessels up to 339 Bar

Lmart has manufactured approximately 60 pressure vessels for Kobe Steel’s (KOBELCO) compressor division across six projects spanning China, Malaysia, Italy, and other international destinations. The equipment includes suction and discharge snubbers, multi-stage separators, intercoolers, aftercoolers, volume bottles, and surge drums — built to GB, ASME VIII Div.1 + DOSH, and PED 2014/68/EU standards, with design pressures reaching 339 Bar and materials ranging from Q345R and 16MnII–IV to SA516 Gr.60, S30408, and duplex 2205.

Customer	Kobe Steel, Ltd. (KOBELCO) — 株式会社神戸製鋼所
Industry	Reciprocating compressor OEM — oil & gas, petrochemical, chemical
Project Locations	China (Xinjiang, Hainan, Changzhou, Yangling), Malaysia, Italy
Equipment	Snubbers, separators, intercoolers, aftercoolers, volume bottles, surge drums (~60 units across 6 projects)
Design Codes	GB/T 150, ASME VIII Div.1 (+ DOSH), PED 2014/68/EU
Key Materials	Q345R, 16MnII/III/IV, SA516 Gr.60, S30408, 16MnDR, SA516 70N, duplex 2205
Max Design Pressure	339 Bar (4th stage discharge — Xinjiang Meike project)
Service	Pulsation dampening, gas/liquid separation, interstage cooling for reciprocating compressors

Customer Background and Industry Context

Kobe Steel, Ltd. (株式会社神戸製鋼所), operating globally under the KOBELCO brand, is one of Japan’s largest industrial conglomerates with annual revenues exceeding ¥2 trillion. Founded in 1905 in Kobe, the company operates across steel, aluminum, machinery, and engineering services. Their machinery division manufactures reciprocating and screw compressors for the oil & gas, petrochemical, and chemical industries — installed in refineries, gas processing plants, and chemical complexes worldwide.

Reciprocating compressors require a family of ancillary pressure vessels that are integral to the compressor package. Suction and discharge snubbers (pulsation dampeners) attenuate pressure pulsations that would otherwise damage downstream piping and instrumentation. Interstage separators remove condensed liquids between compression stages. Intercoolers and aftercoolers manage gas temperature rise during compression. Volume bottles and surge drums provide buffer volume for flow stabilization. These vessels operate at the same pressures as the compressor stages they serve — which in multi-stage reciprocating service can reach 300+ Bar at the final discharge.

KOBELCO’s global project footprint means these ancillary vessels must comply with the pressure vessel code of the destination country: GB for Chinese installations, ASME for international projects (often with additional national requirements like Malaysia’s DOSH certification), and PED for European Union destinations. Finding a single vessel manufacturer qualified across all three codes eliminates the complexity of managing multiple vendors for a single compressor package.

Challenges and Engineering Pain Points

Extreme High-Pressure Design: 339 Bar Service

The Xinjiang Meike project required 4th-stage discharge snubbers rated to 339 Bar — a design pressure that places these vessels firmly in thick-wall, high-pressure territory. At DN250 with 41 mm wall thickness, the wall-to-diameter ratio exceeds 0.16, entering the regime where conventional thin-shell formulas become inaccurate and thick-wall (Lamé) equations must be applied. The material selection — 16MnIV, a Chinese normalized low-alloy steel rated for the highest pressure class — requires PWHT (post-weld heat treatment) and 100% volumetric NDE on all welds. Forged heads and forged nozzle necks replace formed plate components at these pressures, and each forging requires individual material certification and mechanical testing.

Multi-Stage Pressure Progression in a Single Project

The Xinjiang Meike project alone spans four compression stages with design pressures escalating from standard levels at the 1st stage suction (~10–20 Bar) to 339 Bar at the 4th stage discharge. This pressure progression drives a corresponding escalation in material grade — from 16MnII at stages 1–2 through 16MnIII at stage 3 to 16MnIV at stage 4 — and in wall thickness from 11–12 mm at the low-pressure stages to 41–63 mm at the high-pressure stages. Each material grade has distinct welding procedure requirements, preheat temperatures, and PWHT parameters. Managing five material grades (Q345R, 16MnII, 16MnIII, 16MnIV, and duplex 2205 for the aftercooler tubes) within a single project demands rigorous material segregation and traceability systems in the workshop.

Multi-Code Qualification: GB + ASME/DOSH + PED from One Shop

Across the six KOBELCO projects, Lmart delivered vessels certified to three distinct pressure vessel codes: Chinese GB/T 150, ASME VIII Div.1 with Malaysian DOSH endorsement, and European PED 2014/68/EU. Each code imposes different requirements for material acceptance, welding procedure qualification, NDE extent, pressure testing, and documentation format. The ASME + DOSH vessels (Malaysia project) required U-stamp certification plus additional Malaysian regulatory review. The PED vessels (Italy project) required CE marking, notified body involvement, and PED-specific material certifications (EN 10204 Type 3.2). Operating all three code systems simultaneously demands quality management infrastructure that most fabricators — particularly those focused on a single domestic market — do not maintain.

24 Volume Bottles in a Single Shipment

The Malaysia project delivered 24 ASME volume bottles across four separate compressor packages. While individual volume bottles are relatively straightforward pressure vessels, managing 24 units through production with consistent quality, sequential numbering, matched documentation packages, and coordinated export shipping requires manufacturing planning discipline. Each bottle has unique dimensions (DN400–1200, lengths 2,000–5,500 mm) tied to specific piping connections on specific compressor packages — a mis-marked or dimensionally incorrect bottle disrupts the entire package assembly at the project site.

Why Kobe Steel Selected Lmart

Triple-code manufacturing capability. KOBELCO needed a single manufacturer that could produce vessels to GB, ASME (with DOSH), and PED from the same workshop. Lmart holds ASME U stamps, PED manufacturer qualification through a European notified body, and Chinese GB manufacturing licenses — all under an ISO 9001-certified quality management system. This eliminates the need for KOBELCO to qualify and manage separate vendors for each destination market.

High-pressure vessel experience. Design pressures at 339 Bar require specialized thick-wall fabrication capability, including the use of forged components, high-strength low-alloy steels (16MnIII/IV), and PWHT furnaces large enough for the finished vessels. Lmart’s track record with high-pressure service across multiple projects gave KOBELCO confidence in the manufacturing quality for these safety-critical vessels.

Multi-project, long-term supply relationship. The six KOBELCO projects in Lmart’s reference list represent a sustained supply relationship rather than one-off transactions. This continuity means weld procedures, material supply chains, and inspection routines are established and proven — reducing risk and lead time for each successive order.

Batch production efficiency. Projects like the 24-unit Malaysia volume bottle order and the 38-unit Xinjiang Meike package benefit from Lmart’s ability to run batch production of similar vessels with standardized tooling and quality documentation, delivering cost and schedule advantages over fabricators that treat each vessel as a unique job.

Engineering and Manufacturing Solution

The ~60 vessels across six KOBELCO projects share a common function — compressor ancillary service — but span a wide range of sizes, pressures, materials, and code requirements. The manufacturing approach was tailored to each project’s specific demands.

Xinjiang Meike (38 units, GB). The largest single project covered the full four-stage compression train: 16 snubbers (suction + discharge at each stage, qty 2 each), 8 separators, 6 intercoolers, 2 recycle coolers, 2 aftercoolers, and 4 high-pressure snubbers. The pressure escalation from stage 1 to stage 4 required four material grades of increasing strength. The 3rd-stage intercooler (Item 30) at DN350 × 28 mm wall thickness in 20/16MnII and the aftercooler (Item 31) with duplex 2205 tubes represent the most demanding fabrications in this batch. The aftercooler’s 2205 tube-to-tubesheet joints required specialized welding procedures with controlled heat input to preserve the duplex microstructure.

Malaysia (24 units, ASME + DOSH). Twenty-four volume bottles in SA516 Gr.60 across four compressor packages, all at DN400–1200, 12 mm wall thickness, standard pressure service. Despite the straightforward design, the ASME U-stamp + Malaysian DOSH certification requirement added regulatory complexity: each bottle required an Authorized Inspector (AI) review, ASME U-1 form, and supporting documentation formatted for DOSH submission. Lmart’s established ASME quality system streamlined this compliance burden across 24 identical-code vessels.

CNOOC Hainan (8 units, GB). Eight volume bottles in S30408 stainless steel for a CNOOC offshore gas processing application. The stainless steel material selection reflects the corrosive nature of the processed gas stream (likely containing CO&sub2; and/or H&sub2;S). Wall thickness at 10 mm across DN850–1200 indicates moderate design pressures appropriate for the first two compression stages.

Changzhou LANXESS (9 units, GB). Nine volume bottles in S30408 and 16MnDR for LANXESS (a German specialty chemical company) operations in Changzhou, China. The use of 16MnDR — a low-temperature carbon steel — for the 1st-discharge/2nd-suction and 2nd-discharge bottles suggests service involving gases that cool significantly during expansion, requiring impact-tested materials for low-temperature toughness.

Italy (8 units, PED). Eight volume bottles in SA516 Gr.70N for European delivery, requiring PED CE marking and EN 10204 Type 3.2 material certificates. The 26 mm wall thickness at DN850 indicates substantially higher design pressures than the Malaysia or CNOOC projects. SA516 Gr.70N (normalized) provides the combination of strength, weldability, and impact toughness required by PED’s Essential Safety Requirements.

Yangling (14 units + intercoolers, GB). Fourteen surge drums in S30408 and Q345R plus two intercoolers with Q345R shells and S30408 tubes, covering three compression stages for a project in Yangling, Shaanxi Province. The mixed-material intercooler design (Q345R shell / S30408 tubes) balances cost efficiency on the non-wetted shell side with corrosion resistance on the process-side tubes.

Material and Code Summary by Project

Project	Units	Code	Max Pressure	Materials	Equipment Types
Xinjiang Meike	38	GB	339 Bar	Q345R, 16MnII/III/IV, 20, 2205	Snubbers, separators, intercoolers, aftercoolers
Malaysia	24	ASME + DOSH	Standard	SA516 Gr.60	Volume bottles
CNOOC Hainan	8	GB	Standard	S30408	Volume bottles
LANXESS Changzhou	9	GB	Standard	S30408, 16MnDR	Volume bottles
Italy	8	PED	High	SA516 Gr.70N	Volume bottles
Yangling	16	GB	Standard	S30408, Q345R	Surge drums, intercoolers

Representative Equipment Specifications — Xinjiang Meike (High-Pressure)

#	Equipment	Qty	Weight (kg)	DN (mm)	THK (mm)	Length (mm)	Material	Remarks
15	1st Stg. Suction Snubber	2	355	400	12	1,800	Q345R / 16MnII
16	1st Stg. Discharge Snubber	2	328	400	12	1,800	Q345R / 16MnII
20	3rd Stg. Discharge Snubber	2	945	356	35.7	1,900	Q345R / 16MnIII	152 Bar
22	4th Stg. Discharge Snubber	2	928	250	41	1,700	Q345R / 16MnIV	339 Bar
27	1st Dis. Intercooler	2	1,497	356	11.1	4,200	20 / 16MnII
30	3rd Dis. Intercooler	2	3,190	350	28	4,200	20 / 16MnII	139 Bar
31	Aftercooler	2	1,196	219	8.2	3,200	20 / 16MnIII / 2205	306 Bar
32	1st Stg. Suction Snubber	1	2,917	340	60	2,500	16MnIV	322 Bar
33	1st Stg. Discharge Snubber	1	2,239	340	63	2,100	16MnIV	339 Bar

Project Execution, Quality Control, and Delivery

Each of the six KOBELCO projects followed Kobe Steel’s vendor quality requirements, which layer additional controls on top of the applicable pressure vessel code. For the high-pressure Xinjiang Meike vessels, quality control was particularly rigorous.

Key QC milestones:

• Material procurement: 16MnIII and 16MnIV plate sourced from qualified steel mills with full mechanical testing (tensile, impact at design temperature, bend test) per KOBELCO-approved material specifications; forged heads and nozzle necks procured with individual UT examination and material certification
• Weld procedure qualification: separate WPS/PQR packages for each material grade and thickness range, including production test plates for 16MnIV welds to verify joint mechanical properties match base metal requirements
• 100% radiographic testing on all pressure-retaining welds for vessels above 100 Bar; 100% UT on welds inaccessible to RT (nozzle-to-shell welds on thick-wall vessels)
• Post-weld heat treatment: PWHT per code requirements for 16MnIII and 16MnIV vessels, with thermocouple placement documented and time-temperature charts submitted to KOBELCO for review
• Hydrostatic testing at 1.25–1.5× design pressure per applicable code; for 339 Bar vessels, test pressures exceeding 420 Bar requiring high-pressure test pumps and safety protocols
• ASME U-stamp with AI witness for Malaysia volume bottles; PED conformity assessment with notified body for Italy volume bottles
• Nameplate stamping, documentation package assembly (MDR/MRB for ASME, Declaration of Conformity for PED, supervision records for GB), and export packing per KOBELCO specifications

Delivery was coordinated with KOBELCO’s compressor package assembly schedule: high-pressure Xinjiang Meike vessels shipped to the project site in China; Malaysia volume bottles containerized for sea freight to Peninsular Malaysia; Italy vessels shipped CIF to the European port designated by KOBELCO’s logistics coordinator.

Results and Business Impact

Approximately 60 compressor ancillary vessels delivered across six projects, three design codes, and four countries — from a single manufacturer. For KOBELCO, this consolidation reduces vendor qualification overhead, simplifies procurement, and ensures consistent fabrication quality across their global compressor project portfolio.

The Xinjiang Meike project alone represents one of Lmart’s most technically demanding fabrication scopes: 38 vessels spanning four compression stages with pressures from standard to 339 Bar, five material grades, and equipment types ranging from compact snubbers to large-diameter intercoolers. Successful execution at these pressures and material grades establishes Lmart’s credentials for high-pressure vessel service — a market segment where fabricator qualification is a significant barrier to entry.

The sustained multi-project relationship with KOBELCO — one of Japan’s most respected industrial companies — serves as a strong reference for Lmart’s capabilities with other compressor OEMs and Japanese end users evaluating Chinese pressure vessel manufacturers.

Customer Voice

Kobe Steel has placed six separate orders with Lmart for compressor ancillary vessels, spanning GB, ASME, and PED codes. This sustained procurement relationship — rather than any single testimonial — is the strongest evidence of manufacturing capability and reliability.

“Repeat orders across multiple codes and pressure ranges. The 339 Bar snubbers required particular attention to material quality and weld integrity — both met our standards.”

— KOBELCO compressor division (paraphrased from vendor review)

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