The use of natural gas will increase significantly in the next decades necessitating the erection of additional transport infrastructure. Even the transport via gas pipelines is widely used nowadays the transport of liquefied natural gas (LNG) seems to be more economic and flexible to the future prospective which requires new LNG liquefaction plants, re-gasification terminals and LNG carriers.
Although LNG facilities and carriers have an excellent safety record a lot of concerns and questions arise when it comes to build new LNG facilities. LNG itself poses little danger as long as it is contained within storage tanks, piping, and equipment designed for use at LNG cryogenic conditions. Therefore the potential hazards of most concern to operators of LNG facilities and surrounding communities flow basically from accidental release of LNG which may lead to following consequences:
- Pool Fire / Explosion
- Vapour Cloud Creation
- Injuries of persons and embrittlement of supporting components caused by released cryogenic liquid
- Rapid Phase Transition or “flameless explosion”
Even this scenario is rather unlikely – a tremendous effort has been evolved to minimize the risk and to ensure safe LNG operations. A safety concept based on improved containment technology , safety instrumented system (SIS) and safety zones - arranged on LNG vapour dispersion data and thermal radiation contours - is common sense and subject to international regulations and standards.
Safety instrumented systems are supposed to mitigate the effect and hazard of an accidental release of LNG in case of a containment failure. For this level of safety protection, LNG operations use systems such as gas -, cold- and fire detection to rapidly identify any breach in containment and remote and automatic shut off systems to minimize leaks and spills.
Cost - sensitive solution for an entire cryogenic plant supervision
LIOS Technology distributed temperature measurement system (DTS-System) is suited ideally to detect reliably and to locate precisely any temperature anomaly caused by an accidental release of LNG. Our innovative and patented OFDR evaluation method enables the determination of a continuous temperature profile along the entire length of an optical fibre offering thousand of data points at a single measurement. Based on our expert knowledge and our impressive record of safety installations we have developed suitable alarm processing algorithm to detect temperature events fast, reliably and precisely. Also multiple temperature events are identified and pinpointed simultaneously allowing the operator to initiate proper counter measures rapidly.
Utilizing a single fibre optic cable as a purely passive sensor element LIOS Technology DTS system provides an inherently safe operation in explosive atmospheres. The sensor cable does not need any additional wiring, is maintenance free and deployable in areas which are difficult to access. The sensor cable is designed specially to withstand cryogenic temperatures giving a maximum of life time even in rough environments and is easy to install.
With the capability to use up to eight optical channels and a measurement range of several kilometres per channel the LIOS Technology DTS system is a cost - sensitive solution for an entire cryogenic plant supervision including containments, foundations, pumps and piping. The system supplies precise temperature information which facilitates the control of cool-down operations like load- and unload procedures. Additionally an optional loop set-up of the sensor cable enables a redundant operation of the system. Consequently the entire measurement length keeps maintained in case of single fibre break. Summarized the operator takes the following benefit from using LIOS Technology DTS system:
- Full information of containment integrity – everywhere at any time
- Significantly reduced off-times due to exact pinpointing of leaks
- Enabling effective and automatic counter measures
- Fast detection of slow leaks as well as sudden leaks
- Better control of load and unload procedures (cool-down operations)
- Maximum safety of people, assets and environment
- Redundant operation thanks to loop set-up of the sensor cable
- Reduced installation efforts – additional wiring is not required
- Low maintenance efforts and cost
- Long lifetime
Any safety instrumented system is part of a whole safety concept demanding the ability to network and integrate measuring systems into safety management systems. For that reason the LIOS Technology DTS system alarm processing data and temperature profile are transmitted via standard interfaces like TCP/IP using standard protocols like Modbus or XML based data interfaces among others. Furthermore the communication capabilities of LIOS Technology DTS system allows the flexible implementation of user defined protocols enabling subsequent data procession by any PC, PLC or SCADA system specified for the project.