7 Heat Exchangers for AAK Tiger Zhangjiagang Phase 2: Condensers, Falling Film Evaporator & Reboiler in Duplex 2205 and 904L
By Qiangbin Chu · Sales Manager & Operations Lead
Lmart manufactured seven heat exchangers for AAK Tiger’s Zhangjiagang plant expansion (Phase 2) — condensers, a falling film evaporator, condenser/steam generators, a pre-distillation condenser, and a reboiler. The equipment uses Duplex 2205 (S32205/S22053) and 904L (S39042) for corrosion resistance in fatty acid and edible oil refining service, built to GB151 standard.
| Customer | AAK Tiger — 阿胡斯卡尔斯油脂(张家港)有限公司 |
| Industry | Specialty oils & fats — edible oil refining, oleochemical processing |
| Project | AAK Tiger Zhangjiagang Phase 2 plant expansion |
| Equipment | Final condenser, gas phase condenser, condenser/steam generators × 2, pre-distillation condenser, falling film evaporator, reboiler |
| Total Units | 7 |
| Design Code | GB151 |
| Key Materials | Duplex 2205 (S32205), 904L (S39042), Q345R, Q345E |
| Weight Range | 236–9,900 kg per unit |
Customer and Project Background
AAK (formerly AarhusKarlshamn) is a Swedish specialty oils and fats company operating globally in food ingredients, chocolate & confectionery fats, technical products, and animal feed. The Zhangjiagang plant, operated through the Tiger subsidiary brand, is one of AAK’s key production facilities in China for edible oil refining and specialty fat processing.
This Phase 2 expansion follows the original AAK Zhangjiagang project, for which Lmart previously delivered 7 heat exchangers including a predistiller with 6-zone heating system, condensers, a reboiler, and a falling film evaporator (all in Duplex 2205/904L). The Phase 2 order extends the plant’s distillation and refining capacity with additional heat exchange equipment in the same high-alloy material specifications.
The combined AAK scope across both phases totals 14 units — making AAK one of Lmart’s most significant specialty-alloy heat exchanger clients.
Complete Equipment Specifications
| # | Equipment | Qty | Weight (kg) | DN (mm) | THK (mm) | Length (mm) | Material |
|---|---|---|---|---|---|---|---|
| 135 | Final Condenser (最终冷凝器) | 1 | 2,350 | 800 | 8 | 3556 | Shell: S22053 / Tube: S22053 |
| 145 | tBA Product Gas Phase Condenser | 1 | 236 | 273 | 8 | 862 | Shell: Q345E / Tube: Q345E |
| 146 | Condenser / Steam Generator | 1 | 3,295 | 1710 | 8 | 1497 | Shell: Q345R / Tube: S32205 |
| 147 | Pre-Distillation Condenser | 1 | 5,600 | 1400 | 8 | 4480 | Shell: S32205 / Tube: S32205 |
| 148 | Falling Film Evaporator | 1 | 9,900 | 1400 | 30 | 2705 | Shell: Q345R / Tube: S39042 (904L) |
| 149 | Condenser / Steam Generator | 1 | 3,290 | 1660 | 8 | 1441 | Shell: Q345R / Tube: S32205 |
| 150 | Reboiler | 1 | 3,200 | 950 | 26 | 1787 | Shell: Q345R+S32205 / Tube: S39042 (904L) |
Engineering Challenges
Duplex 2205 Welding for Edible Oil Refining
Duplex 2205 (UNS S32205/S22053) is specified throughout this project for its combination of high strength and superior corrosion resistance to fatty acids, particularly at the elevated temperatures encountered in oil distillation and deodorization processes. Welding Duplex 2205 requires strict control of heat input (typically 0.5–2.5 kJ/mm) and interpass temperature (maximum 150 °C) to maintain the target 40–60% ferrite/austenite phase balance. Excessive heat input promotes sigma phase formation, which destroys both toughness and corrosion resistance. Lmart’s qualified Duplex welding procedures, developed through the Phase 1 AAK project and multiple Alfa Laval PureSOx campaigns, were directly applicable to Phase 2.
904L Tubes in Falling Film and Reboiler Service
The falling film evaporator (item 148) and reboiler (item 150) use 904L (S39042) tubes — a super-austenitic grade with 4.5% Mo that provides exceptional resistance to localized corrosion in hot fatty acid distillation media. 904L is significantly more expensive than Duplex 2205, so its use is limited to the tube-side (wetted by concentrated process fluids) while the shell side uses Q345R carbon steel with Duplex 2205 cladding where needed. Welding 904L tubes to the tubesheet requires matching filler metals and post-weld ferrite verification to ensure the weld deposit retains the alloy’s corrosion performance.
Compact Condenser/Steam Generator Design
The two condenser/steam generators (items 146 and 149) are large-diameter, short-length vessels — DN1710×1497 mm and DN1660×1441 mm respectively. This aspect ratio concentrates heat transfer surface into a compact footprint for integration into AAK’s distillation column overhead systems. The Q345R shell with Duplex 2205 tubes handles the vapor condensation on the tube side while generating low-pressure steam on the shell side for heat recovery.
Continuity from Phase 1
The Phase 1 AAK Zhangjiagang project delivered 7 units including a predistiller with 6-zone heating system (8,800 kg, DN2600, Duplex 2205 shell with 904L tube systems), condensers, and a falling film evaporator. Phase 2 extends this scope with additional distillation capacity. The material specifications, welding procedures, and inspection protocols established in Phase 1 carried directly into Phase 2 — reducing qualification time and ensuring consistency across the entire installed equipment fleet.
Total combined weight across both phases exceeds 70,000 kg of fabricated equipment in Duplex 2205 and 904L — establishing Lmart as AAK’s primary high-alloy heat exchanger fabricator for the Zhangjiagang facility.
Why AAK Tiger Selected Lmart for Phase 2
Proven Phase 1 performance. The 7-unit Phase 1 delivery established Lmart’s capability with Duplex 2205/904L fabrication, welding qualification, and inspection documentation for edible oil refining service. Phase 2 was a natural continuation.
Duplex and super-austenitic expertise. Fabricating pressure vessels in Duplex 2205 and 904L requires specialized welding knowledge, ferrite measurement capability, and alloy-specific NDT acceptance criteria. Lmart’s accumulated experience across AAK, Alfa Laval, and other Duplex projects provides depth in this specialty.
Local manufacturing for Zhangjiagang installation. Lmart’s facility is located in Zhangjiagang — the same city as AAK Tiger’s plant. This eliminates long-distance transport logistics for heavy, oversized equipment and enables AAK’s engineering team to conduct witness inspections at minimal cost.
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Customer Voice
AAK Tiger’s decision to award Phase 2 to the same fabricator that delivered Phase 1 reflects satisfaction with quality, schedule, and commercial terms. In specialty-alloy process equipment, switching fabricators between phases introduces re-qualification risk that AAK chose to avoid.
Note: Lmart respects client confidentiality. Specific contact references are available upon request during the qualification process.