Zhejiang Satellite Petrochemical — LPG BOG (2018) — Boil-Off Gas Compression for Propane Tank Area
By Qiangbin Chu · Sales Manager & Operations Lead
Zhejiang Satellite Petrochemical is one of China's leading C2/C3 chemical producers, operating integrated propane dehydrogenation (PDH), acrylic acid, and downstream chemical facilities. The company imports large volumes of LPG (primarily propane) via ocean-going vessels, storing it in refrigerated tanks at the Jiaxing terminal before feeding it to the PDH units that produce propylene.
| Client | Zhejiang Satellite Petrochemical Co., Ltd. |
| Plant / Unit | LPG BOG Compressor — Propane Tank Area |
| Equipment | BOG Compression Package × 2 |
| Design Code | GB |
| Motor Power | 630 kW per unit |
| Gas Handled | Propane mixture (boil-off gas) |
| Application | Propane tank area BOG recovery |
| Design Institute | Wuhuan Engineering Co., Ltd. |
| Year | 2018 |
Customer Background
Zhejiang Satellite Petrochemical is one of China’s leading C2/C3 chemical producers, operating integrated propane dehydrogenation (PDH), acrylic acid, and downstream chemical facilities. The company imports large volumes of LPG (primarily propane) via ocean-going vessels, storing it in refrigerated tanks at the Jiaxing terminal before feeding it to the PDH units that produce propylene.
Refrigerated propane storage tanks generate continuous boil-off gas due to ambient heat gain. The BOG volume increases during tanker unloading operations when warm LPG mixes with stored cold product. Compressing and recovering this BOG is essential for both economic and safety reasons — uncontrolled BOG buildup increases tank pressure, potentially triggering relief valve discharge or requiring flaring.
Satellite Petrochemical’s propane storage capacity is among the largest in China’s private petrochemical sector, supporting PDH units that produce over 1 million tonnes per year of polymer-grade propylene. The BOG compression system is a critical utility that must operate continuously to maintain safe tank pressure and maximize feedstock recovery.
Challenges and Engineering Requirements
System Integration and Package Design
Compressor packages are not standalone machines — they are integrated systems combining the compressor, driver, interstage coolers, separators, control panels, piping, and instrumentation on a common skid frame. Every component must be engineered to work together: gas flow paths optimized to minimize pressure losses, vibration isolation designed to prevent resonance between rotating equipment and the skid structure, and control logic programmed to protect the compressor across all operating conditions.
Process Gas Compatibility
Compressing BOG Compression Package × 2 service in the petrochemical processing sector requires materials and seal systems compatible with the specific gas composition, including trace contaminants that can cause accelerated corrosion, elastomer degradation, or lubricant breakdown. The design must address gas properties at each compression stage — temperature rise, condensation risk, and molecular weight changes for gas mixtures.
Noise, Vibration, and Mechanical Integrity
Reciprocating and screw compressors generate significant dynamic forces that propagate through the skid structure to the foundation. The package design must account for pulsation dampening, piping flexibility analysis, and anchor bolt sizing to prevent fatigue failures in connected piping and instrumentation. Acoustic enclosures or silencers may be required to meet plant noise limits.
Why Zhejiang Satellite Petrochemical Co., Ltd. Selected Lmart
Turnkey package engineering. Lmart provides complete compressor package engineering including process simulation, mechanical design, structural analysis of the skid frame, piping stress analysis, and control system programming — delivered as a factory-tested, ready-to-install module.
Multi-gas experience. Lmart has delivered compression packages for natural gas, BOG (boil-off gas), propylene, hydrogen, chloromethane, and other process gases, each with its own material compatibility, seal technology, and safety requirements.
Workshop integration and testing. Complete packages are assembled, piped, wired, and functionally tested at Lmart’s facility before shipment. Factory acceptance testing includes mechanical run tests, control loop verification, and safety system validation.
Technical Scope and Specifications
Two BOG compression packages compress propane-rich boil-off gas from the propane tank area to pipeline delivery pressure. Each unit features a 630 kW motor — larger than the 450 kW units supplied for the propylene BOG project in 2017, reflecting the higher gas volumes from the larger propane storage facility.
Key design considerations:
- Higher capacity: The propane tank area generates more BOG than the acrylic tank area due to larger tank volumes and more frequent ship unloading operations, requiring the step-up from 450 kW to 630 kW motor rating
- Propane mixture handling: BOG composition varies between steady-state tank holding (nearly pure propane) and ship unloading events (mixed with ethane, butane, and heavier components), demanding flexible compressor operating range
- Peak load during unloading: Ship-to-tank transfer operations create transient BOG spikes that can exceed steady-state generation by an order of magnitude — the dual-compressor arrangement provides the surge capacity needed
- Integration with tank pressure control: Compressor suction tracks tank vapor space pressure via automated control, maintaining the tank within safe pressure limits during all operating modes
- Wuhuan Engineering standards: Consistent with the propylene BOG compressors delivered in 2017, ensuring operational and maintenance commonality across Satellite Petrochemical’s compression fleet
This was the second compression project Lmart delivered for Satellite Petrochemical, following the propylene BOG compressors in 2017. The continuity of design institute (Wuhuan Engineering) and manufacturer (Lmart) across both projects simplified procurement, spare parts management, and operator training.
Delivery and Quality Assurance
Both packages were factory-assembled and tested at Lmart’s Zhangjiagang facility, following the same quality protocol established for the 2017 propylene BOG compressors. Testing included mechanical run-in with vibration monitoring, oil system cleanliness verification, relief valve setting checks, and complete instrument loop testing. Pressure vessels were hydro-tested per GB 150, and all materials were verified against mill test certificates.
Delivering to the same facility allowed Lmart to coordinate with the existing 2017 compressor installation, ensuring operational and maintenance commonality between the propylene BOG and LPG BOG compression systems. Wuhuan Engineering’s consistent specification framework across both projects further simplified integration and operator training.
Results and Business Impact
Lmart successfully delivered 2 units of BOG Compression Package × 2 to Zhejiang Satellite Petrochemical Co., Ltd., 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.”
— Zhejiang Satellite Petrochemical Co., Ltd. project team (paraphrased from project review)
Note: Lmart respects client confidentiality. Specific contact references are available upon request during the qualification process.