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Integrated Automation Solutions for Advanced LNG Transportation
Shardul Sirsamkar, Global Solutions Marketing Manager, Marine Honeywell Process Solutions Global demand for natural gas is growing faster than for oil and coal. This demand is estimated to exponentially grow till at least 2030. Demand growth is driven by the increasing number of nations strategically adopting environmentally cleaner fuels to meet future economic growth and prioritizing alternatives to minimize the impact of increasing oil based energy costs. With USA about to begin gas export and with large populated countries like China continuing to grow imports, we can expect substantial growth in LNG transportation business.

LNG is the preferred method of transporting natural gas and involves chilling the gas to minus 162 degrees Celsius. LNG is transported in specially designed ships with double hulls protecting the cargo systems from damage or leaks. Over a period of time we have seen various changes in LNG transportation vessels, primarily in the method of propulsion, or driving the carrier ship. Initially LNG carriers operating on Conventional Steam-Turbine Systems, used gas that evaporates from the chilled LNG tanks. As ships became bigger it was not possible to use all of the evaporated gas, so new methods were invented to convert the gas back to LNG, hence these vessels were built with Re-liquefaction plants onboard.
Also it became feasible to reduce the footprint of the importing LNG terminal in some cases by creating some of the facility on board itself. This gave birth to the Re-gasification type LNG carriers; which allowed savings on LNG Terminal capital costs and also allowed offshore unloading of the LNG straight into the gas network which eased the NIMBY (Not In My Back Yard) lobbyists in some regions. Next generation vessels were DFDE (Dual Fuel Diesel Electric System) types which added a different dimension to LNG transportation business and now, in all probability, the future is MEGI (Main Engine Gas Injection), with shipyards, ship-owners and charterers already discussing this advanced technology. With such changes in the types of vessels over the years, LNG transportation vessels have become more and more complex in design as well as operations and maintenance. Also, LNG Carrier leasing rates have varied widely from a stable $50,000 per day a decade ago up to $120,000 per day in 2012. These factors create immense pressure to increase efficiency and reduce operating costs, while complying with even more stringent regulatory standards, CAPEX constraints, safety onboard, retaining experienced crew and other serious challenges associated with LNG transportation fleets.

Technology has come to the rescue to create a more intelligent LNG carrier that is capable of improved self management and thereby reducing some of the operating complexities that would otherwise have exploded. The response to these challenges is in the form of an IAS, in other words an “Integrated Automation System” which has some really interesting capabilities to reduce complexity in operating and maintaining the LNG carrier. IAS is a control system with basic functions – sensing, monitoring, alarm and control. Engineering workstations, HMI (Human Machine Interface), control network and distributed & scalable controllers are its basic components. In general, IAS offers seamless integration with security, telecom, electrical systems etc. On LNG Carriers, IAS solutions integrate production, processing and transportation operations and link them with security, safety, commercial, regulatory and environmental functions. As a result, ship operators can improve staff productivity, lower operating costs, capitalize on key business opportunities such as spot trade, improve asset utilization and boost profitability.
The best IAS technologies include special techniques from the Abnormal Situation Management Consortium™. The ASM™ is the global peak industry body for producing design recommendations to improve the ship’s crew to pre-empt and respond to excursions outside of the ships safety envelope. Such technology also adds a great deal in ensuring safety on board. Top IAS providers offer dynamic simulation based training systems that are so realistic that they have become indispensible for understanding the system, certifying novices and maintaining experienced staff.

Measurement instruments were the first step in the field of process automation that were devices that could sense physical properties such as temperature, pressure, flow and so on and convert the measurement to an accurate voltage signal to interface to a dial or other device. The DCS (Distributed Control System) was one of the earliest developed "digital control systems" and were designed to connect to these instruments. The next step was to integrate boilers with IAS on LNGC. A few years after that, IAS became advanced with integration to compressor control application. RIO (Remote IO) was introduced to take it to the next level. Greater improvements were achieved by integration with PMS (Power Management System), CCTV System, CTS (Custody transfer system) etc. This is known as "continuous evolution". It is important for IAS manufacturers to keep investing in order to achieve greater amount of integration and bring simplicity to the complex operations onboard.
The picture below covers the generic scope of IAS on LNG Carriers and gives an overview of the depth of integration onboard:

Originally the measurement instruments provided analog voltage signals that provided only one signal or item of information. Digital information transfer eventually overtook analog, and now the majority of smart field devices installed worldwide today are HART-enabled. HART (Highway Addressable Remote Transducer) is a bi-directional communication protocol that provides data access between intelligent field instruments and host systems. This technology offers many benefits - continuous status monitoring and advanced diagnostics. It allows extended maintenance intervals and pinpointing of specific problems without even going to the field. We haven’t seen much of HART on LNG vessels yet, but in the future, we can expect to see it used onboard extensively.
Fieldbus made an appearance on LNG Carriers a long time back. Foundation Fieldbus is not popular here but the alternative Profibus has been a part of stable LNG Carrier solutions for quite some time now. Profibus and Fielbus are both single bus based systems that allow many instruments to be connected to one simple cable, as compared to the analog and HART devices that require individual wiring on each device. This bus technology offers true openness and total interoperability with many vendor options. It helps to reduce weight and space on-board with less hardware required and also helps to lower installation and life cycle costs.
Recently wireless instruments entered into the marine market with installation on oil tankers and very soon will reach LNG carriers. These days wireless solutions come with complete system redundancy (including redundant interface to IAS), prioritized wireless traffic and update rates as fast as 1 sec. Wireless devices with 10 years battery life and superior antenna diversity are available easily. These solutions offer great cost savings in terms of reduced wiring, engineering and commissioning cost and also offer asset management and proactive maintenance. Other important aspects onboard where IAS plays a major role are remote access, network security and cyber security.
IAS network can roughly be divided into different levels: Level 1 – Process control level, Level 2- Supervisory control level, Level 3- Advanced control level and Level 4 – Outside of IAS. When IAS is accessed from ship-owner HQ, it is important to check to which network level of IAS, the access is being provided. Use of firewall, DMZ (De-Militarized Zone), prioritized traffic, storm suppression are keys for good networking practices which don’t allow direct access from outside of IAS to any of the levels. Within IAS itself, it is considered as a good practice that only two levels communicate with each other directly. Use of control firewall between the process control level and supervisory control level is also highly advisable.

With increasing complexity in LNG vessels, it has become absolutely critical that the crew understands the working of IAS perfectly. Maintaining expert and experienced crew is quite challenging and OTS helps to overcome this challenge.
It is ideal to have OTS which is portable and offers realistic simulation. Also it is vital that OTS is based on the latest technology and suits various environments. The physical processes in modern LNG Carriers are complex and for that reason the “first principles” dynamic simulators are preferable to simpler, lower-fidelity methods. It is important that IAS manufacturers offer OTS for different needs. Example – OTS on laptop is sufficient for manager level training whereas multiple PCs with dual screens and membrane operator keyboards are required at the Ship-owner HQ or Maritime Academy deployment, for conducting training courses OTS. For maintenance training courses, additional hardware is required and shipyards need high fidelity OTS for development of new designs.

Assurance of support for control systems throughout the life of the vessel and availability at any global location is of utmost importance. This becomes even more critical as technology advances, during shipping personnel changes and when vessels begin to trade in spot cargos and visiting ports not on established routes.
To provide the unique support required for the marine industry, IAS manufacturers should have a global marine support network offering 24 hours a day call-centre with access to worldwide LNG carrier support-personnel and guaranteed quick response. Services should include centralized coordination of spares, remedial maintenance, preventive maintenance, modifications and upgrades, dry dock maintenance, warranty support and training.