Rotating Machinery Controls for LNG Import/Export Terminals

LNG facilities, whether importing or exporting, utilize a significant amount of rotating machinery equipment for refrigeration, gas compression, and onsite power generation. LNG contracts are often negotiated years in advance and contain supply commitments with penalties for non-performance. The facilities’ assets are required to deliver exceptional reliability, availability, and optimal performance.

Background & Customer Needs/Requirements

A LNG facility was having difficulty servicing and maintaining an OEM system that controlled one of its turbine-generators. This turbine is considered critical as it provided electrical power for the islanded site that has no connection to the grid.

• The control system would frequently and unexpectedly trip the turbine, as often as once per month.
• Fault diagnosis was complicated and service support was difficult to obtain. Often times faults went undiagnosed.
• Unhappy with performance of hydraulic valve actuators and other mechanical systems
• Support for the control system and mechanical systems was problematic due to a lack of US based support.
• No integration of control system into DCS

The facility needed help. Its requirements included:

• Eliminate “spurious” shutdowns
• Properly communicate the reasons for valid shutdowns, and increase the serviceability by site personnel
• Increase the reliability and availability of the control system and its components
• Provide high levels of control performance for turbine speed, generator power, and supplied steam pressure
• Provide new and highly reliable hydraulic actuators
• New redundant turbine protection trip system
• Include a high degree of support, whenever necessary, from the control system vendor
• Support site to integrate the controls into their DCS for ease of operation

Wunderlich-Malec ’s Approach & Solutions

CASE RMC’s project team began discussions with the facility to fully understand their issues and to determine where CASE RMC’s expertise and decades of applicable experience could be of value. Assessment of the facilities needs led to a preliminary system design which was refined with ongoing client input.

Ultimately, CASE RMC was able to develop and propose a system emphasizing operability, reliability, and maintainability of the new equipment and components.

The CASE RMC scope of work included:

• Full-scope project design and execution, including installation and startup support
• Custom cabinets and field enclosures, fabricated and tested in-house at CASE RMC
• Woodward MicroNet Plus digital control with primary and expansion racks for I/O
• Custom CASE RMC enhancements to improve the performance and operability of the OEM turbine control philosophy
• High-pressure hydraulic actuation w/ redundant servo and feedback devices
• Overspeed detection and protection via a Woodward ProTech TPS and full CASE RMC electro-hydraulic turbine protection system … 100% online testable and 100% online repairable
• Rockwell FactoryTalk HMI, plus Modbus TCP link to the site’s DCS
• In-house Factory Acceptance Test using CASE RMC’s closed-loop hardware-based turbine simulator
• Electrical installation and I/O checkout with support of the field electrical installer
• Turnkey hydraulic and mechanical installation
• On-going, cradle-to-grave systems support by CASE RMC, including spare parts and maintenance