Wanhua Chemical — MDI C₂H₄ Tank (2021) — Direct Cooling System
By Qiangbin Chu · Sales Manager & Operations Lead
Wanhua Chemical Group Co., Ltd. is the world's largest MDI (methylene diphenyl diisocyanate) producer. The MDI complex includes ethylene (C₂H₄) storage tanks that must be kept well below the boiling point of ethylene (−104 °C) to prevent boil-off and maintain safe inventory levels.
| Client | Wanhua Chemical — MDI C₂H₄ Tank (2021) |
| EPC / Design Institute | Hualu Engineering & Technology Co., Ltd. |
| Equipment | Direct Cooling System × 1 set |
| Design Code | GB |
| Cooling Capacity | 1,300 kW |
| Motor Power | 1,400 kW |
| Refrigerant | R507 |
Customer Background
Wanhua Chemical Group Co., Ltd. is the world’s largest MDI (methylene diphenyl diisocyanate) producer. The MDI complex includes ethylene (C₂H₄) storage tanks that must be kept well below the boiling point of ethylene (−104 °C) to prevent boil-off and maintain safe inventory levels.
Challenges and Engineering Requirements
Process Temperature Control in petrochemical processing
Wanhua Chemical required precise low-temperature cooling for Direct Cooling System × 1 set service in the petrochemical processing sector. The brine chiller system must maintain stable outlet temperatures within narrow tolerances despite variable process heat loads. Fluctuations in feed composition, ambient temperature swings, and seasonal load variations all affect the refrigeration duty — the system must respond to these changes while protecting compressor operation from surge and liquid carryover.
Refrigerant Selection and Safety
The choice of R507 reflects the balance between thermodynamic efficiency at the target evaporating temperature, compatibility with the plant’s existing refrigerant infrastructure, and safety classification under the applicable code. Each refrigerant brings specific considerations: flammability limits for hydrocarbon refrigerants, operating pressure ranges that affect component sizing, and oil miscibility that influences compressor lubrication system design.
Integration with EPC Engineering
The chiller packages were specified and documented by Hualu Engineering & Technology Co., Ltd. as part of a larger process unit. This means every interface — brine supply/return connections, electrical load requirements, control signal protocols, and physical footprint — must match the EPC’s plot plan and P&ID exactly. Any deviation requires formal design change management, adding time and cost to the project.
Why Wanhua Chemical Selected Lmart
Integrated refrigeration package capability. Lmart designs and manufactures complete refrigeration systems — compressor selection, heat exchanger sizing, piping layout, control logic, and skid-frame engineering — as a single-source supplier. This eliminates the interface risks that arise when the chiller vendor, vessel fabricator, and system integrator are separate companies.
Process refrigerant experience. Lmart has delivered refrigeration packages using propylene, propane, ammonia, R134a, and other process refrigerants across petrochemical, chemical, and marine applications. This experience base means the engineering team understands the specific requirements of each refrigerant — safety classifications, oil management, capacity control methods — without a learning curve.
Repeat performance. Lmart has delivered equipment to Wanhua Chemical and similar clients in the petrochemical processing sector, demonstrating consistent quality and on-time delivery performance across multiple projects.
Equipment & Scope of Supply
Lmart supplied one (1) direct cooling system rated at 1,300 kW for the ethylene tank farm within the MDI facility. Unlike brine-chiller configurations, this direct-cooling package condenses and sub-cools ethylene vapour directly using an R507 refrigeration cycle, eliminating the secondary heat-transfer loop. The compressor is driven by a 1,400 kW motor, and the system was designed to GB standards.
The project was engineered by Hualu Engineering & Technology Co., Ltd., who also oversaw the integration of the cooling package with the tank farm’s pressure-control and safety instrumentation.
Quality Control and Project Execution
All equipment was manufactured under Lmart’s ISO 9001-certified quality management system with the following key inspection milestones:
- Material verification: Incoming inspection of all plates, forgings, and fittings against mill certificates; PMI spot checks on alloy materials
- Welding quality: All welding performed by qualified welders using approved WPS/PQR; NDE per GB requirements including RT/UT on pressure-retaining welds
- Dimensional inspection: In-process dimensional checks at shell rolling, head forming, and final assembly stages
- Pressure testing: Hydrostatic test to GB requirements, witnessed by the authorized inspector and/or client representative
- Documentation package: Complete data book including material certificates, weld maps, NDE reports, dimensional records, and test certificates
Equipment was delivered to Wanhua Chemical’s project site in China, meeting the project schedule requirements.
Results and Business Impact
Lmart successfully delivered 1 units of Direct Cooling System × 1 set to Wanhua Chemical, meeting the project’s quality, schedule, and documentation requirements. The equipment was manufactured to GB standards, with full documentation packages accepted by the client and applicable inspection authorities.
This project reinforces Lmart’s position as a qualified manufacturer for petrochemical processing applications, demonstrating the company’s ability to deliver equipment that meets international quality and certification standards.
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Customer Voice
“The equipment was delivered on schedule and the documentation package was complete. The quality of fabrication met our inspection requirements.”
— Wanhua Chemical project team (paraphrased from project review)
Note: Lmart respects client confidentiality. Specific contact references are available upon request during the qualification process.