Receiving the gift that is LNG

Allen Yeh, CTCI Corporation, Taiwan, considers the construction of LNG receiving terminals and the factors that must be understood prior to investing in these terminals.

As the world is committed to reducing carbon emissions and curbing global warming, Asian s the world is committed to reducing carbon emissions and curbing global warming, Asian countries have responded to carbon reduction and are moving towards net-zero carbon countries have responded to carbon reduction and are moving towards net-zero carbon emission. Replacing traditional coal-fired power generation with gas-fired power plants emission. Replacing traditional coal-fired power generation with gas-fired power plants is an important policy for many countries to actively promote the energy transition. Both public is an important policy for many countries to actively promote the energy transition. Both public sectors and private enterprises have invested in the construction of LNG receiving terminals to sectors and private enterprises have invested in the construction of LNG receiving terminals to meet the growing demand for gas supply. According to the International Energy Agency (IEA), meet the growing demand for gas supply. According to the International Energy Agency (IEA), the number of countries with LNG receiving terminals in the world has increased from nine in the number of countries with LNG receiving terminals in the world has increased from nine in 2000 to 42 in 2020, and the increase is mainly concentrated in Asian countries such as Japan, 2000 to 42 in 2020, and the increase is mainly concentrated in Asian countries such as Japan,

China, South Korea, India, and Taiwan. Other countries like Vietnam, Indonesia, the Philippines, China, South Korea, India, and Taiwan. Other countries like Vietnam, Indonesia, the Philippines, and Bangladesh are also committed to achieving their development plans of LNG receiving and Bangladesh are also committed to achieving their development plans of LNG receiving terminals. terminals.

LNG receiving terminal work LNG receiving terminal work

The construction of a complete LNG receiving terminal mainly includes marine works, storage tanks, regasification, The construction of a complete LNG receiving terminal mainly includes marine works, storage tanks, regasification, buildings, and related facilities. It takes approximately five to seven buildings, and related facilities. It takes approximately five to seven years from carrying out an environmental impact years from carrying out an environmental impact assessment and obtaining government construction permits to the completion of the engineering, procurement, assessment and obtaining government construction permits to the completion of the engineering, procurement, construction, and commissioning works. Activities at an LNG receiving terminal can be divided into four main stages: construction, and commissioning works. Activities at an LNG receiving terminal can be divided into four main stages: berthing of ships and unloading of cargoes; storage of LNG in cryogenic tanks; LNG regasification; and send-out of gas berthing of ships and unloading of cargoes; storage of LNG in cryogenic tanks; LNG regasification; and send-out of gas into the transmission grid. into the transmission grid.

Marine work Marine work

An LNG jetty is a construction work projecting pipelines from an onshore terminal out over water. It often consists of piles, An LNG jetty is a construction work projecting pipelines from an onshore terminal out over water. It often consists of piles, a trestle and topsides, pipelines, access road, unloading/loading arms, and breasting and mooring dolphins. The process of a trestle and topsides, pipelines, access road, unloading/loading arms, and breasting and mooring dolphins. The process of designing and constructing a jetty can be time-consuming, costly, and requires intervention in both onshore and marine designing and constructing a jetty can be time-consuming, costly, and requires intervention in both onshore and marine environments. A jetty also serves as a connection that enables transfer of LNG between a berthed ship and the onshore environments. A jetty also serves as a connection that enables transfer of LNG between a berthed ship and the onshore terminal. Based on economic and fire-fighting considerations, LNG terminals generally adopt breasting and mooring terminal. Based on economic and fire-fighting considerations, LNG terminals generally adopt breasting and mooring dolphin types of jetties, which are connected to onshore facilities by trestles. dolphin types of jetties, which are connected to onshore facilities by trestles.

The length of the trestle may vary from tens of metres to several kilometres according to local conditions, such as port The length of the trestle may vary from tens of metres to several kilometres according to local conditions, such as port planning, seabed depth, environmental protection requirements, etc. The construction of the long span trestle may use a planning, seabed depth, environmental protection requirements, etc. The construction of the long span trestle may use a customised equipment called a cantilever bridge – this equipment is capable of shifting the work front forwards over the customised equipment called a cantilever bridge – this equipment is capable of shifting the work front forwards over the already constructed trestle part on a span by span approach, without suffering from impacts of water depth and wave already constructed trestle part on a span by span approach, without suffering from impacts of water depth and wave conditions. conditions.

For an LNG receiving terminal that uses seawater for LNG regasification (such as ORV and IFV facilities), seawater inlet/ For an LNG receiving terminal that uses seawater for LNG regasification (such as ORV and IFV facilities), seawater inlet/ outfall (SW I/O) is also one of the important tasks of the marine works, especially the design and construction of the inlet outfall (SW I/O) is also one of the important tasks of the marine works, especially the design and construction of the inlet

pit. It is worth noting that some projects must use the shield construction method due to environmental protection requirements. Although this method can reduce the impact on the environment, the cost and schedule risks are much higher than that of traditional open-cut construction, and the construction machinery is relatively complicated. As seawater is corrosive to metals, RC and FRP materials are used for seawater conveying pipes.

Tank

An LNG storage tank is a specialised type of storage tank used to store LNG at the very low temperature of -162˚C (-260˚F). Many newly-built or under construction LNG receiving terminals adopt an above-ground type of full containment storage tank, which is composed of 9% nickel steel plate inner wall and pre-stressed concrete (PC) outer wall. Due to the height of the LNG storage tank, the PC outer wall is constructed with system forms, such as slip form or jump form.

Subject to the code/regulation requirements to knuckle plate fabrication, currently the common storage tank capacities for double dome roof type are from 180 000 - 230 000 m3. The suspended roof type provides more flexibilities in the range of capacities, including the ongoing two 250 000 m3 tanks of Thailand PTTLNG and the completed 260 000 m3 tank of Singapore LNG (SLNG).

Roof air raising is one of the most critical tasks in the construction of LNG storage tanks. It is an irreversible procedure because re-lifting may cause the sealing material metal mesh to break or rupture, as well as risk of leaking air pressure, resulting in an imbalance of the storage tank roof and becoming stuck on the pre-stressed concrete wall. In normal practice, contractors will arrange roof pre-air-raising and official roof air raising. Weather conditions, especially wind speed, are also crucial and must be considered during roof air raising.

Figure 1. Roof air raising in CPC’s third LNG receiving terminal, Taiwan. Image courtesy of CPC Corporation.

Figure 2. First berthing after expansion of the Petronet Kochi LNG receiving terminal, India.

Regasification facilities

There are different types of regasification vaporisers, such as open rack vaporiser (ORV), shell and tube vaporiser (STV), submerged combustion vaporiser (SCV), and intermediate fluid vaporiser (IFV). The choice of vaporiser will vary according to the characteristics of the project. Primary considerations include plant conditions, normal and peak-shaving gas supply requirements, local climate, seawater temperature and cleanliness, energy efficiency, maintenance requirements, and costs. To save energy and minimise greenhouse gas emissions, it is ideal to use ‘free heat’ from the ambient air or seawater when selecting the type of vaporiser for an LNG receiving terminal.

Considering operation and maintenance costs, in areas where seawater is very clean, ORVs are generally selected for base load operations; otherwise, IFVs will be adopted. SCVs are reserved for peak gas supplies and serve as back-up vaporisers when ORVs or IFVs are under maintenance.

Integrating the inlets/outfalls of the LNG receiving terminal with the nearby combined cycle power plant (CCPP) can help improve energy efficiency and reduce each other’s operating costs. The idea is that seawater can be used as a heat source of the LNG vaporiser in the LNG receiving terminal as well as a cold source for condensing the steam discharged from the steam turbine in the combined cycle power plant.

Buildings

Buildings (including administration, maintenance, substation, control room, guard house, etc.) are the common facilities for an LNG receiving terminal. However, Thailand’s PTTLNG adopted a different strategy by transforming the administration building of Nong Fab Terminal from a closed plant facility to a public education centre, allowing ordinary citizens and students to take electric vehicle tours and visit green buildings, rooftop solar power generation facilities, and wind power generation facilities. This helps educate people about the significance of this energy source, the production process, and the benefit of LNG.

The administration area consists of an administration building, two support buildings, and large landscape areas. The administration area features an educational zone, exhibition hall, an in-plant power generation facility (wind turbine and solar cell) together with an LNG cold energy utilisation system which can generate and send the cold air – the byproduct collected from the regasification process – into the climatic dome in order to maintain the required ecological environment for the winter flowers inside.

Cold energy utilisation

During the process of LNG regasification, a large amount of cold energy will be released. To some degree, a considerable amount of cold energy will be available when importing LNG. Possible cold energy applications in LNG receiving terminals

CTCI Group

CTCI is a global engineering services provider that offers a comprehensive range of services, products, and solutions. Since its founding in 1979, CTCI has strived to deliver the world’s most reliable engineering, procurement, fabrication, construction, commissioning and project management services. Headquartered in Taipei, Taiwan, CTCI serves the hydrocarbon, power, environmental, transportation and industrial markets. The company is Taiwan’s leading EPC services provider, Currently it has around 40 operation bases in over 10 countries with about 7,000 employees, and is a member of the Dow Jones SustainabilityTM Emerging Markets Index.

Markets

• Hydrocarbon • Power • Environmental • Transportation • Industrial

Services

• Project Management • FS/FEED • Engineering • Procurement • Fabrication • Construction • Commissioning • Intelligent Solutions • Automation & Control • Cleanroom & MEP • Intelligent Structure Jacking & Movement • Ground Freezing • Operation & Maintenance

Products

• Stationary Equipment • Chemical Additives • Energy Management System

CTCI Group

89, Sec. 6, Zhongshan N. Rd., Taipei 11155, Taiwan, R.O.C. Tel: (886)2-2833-9999 Fax: (886)2-2833-8833 include supply of air conditioning (HVAC) for buildings inside the terminal, cold energy power generation, intake air cooling for in-plant power generation (i.e. GTG) and/or nearby combined cycle power plants (CCPP) to improve their performance efficiency. The cold energy can also provide adjacent areas an integrated utilisation of resources, such as air separation to produce liquid nitrogen and liquid oxygen, cold storage warehouse, and low temperature fishery, etc. Compared to other applications, the application of air separation has more economic value.

However, initially most of the existing LNG receiving terminals were set up to provide stable supply of natural gas rather than cold energy application purposes. Insufficient demand from surrounding industries, constraints on land use, insufficient economic benefits from application projects, and unclear policy directions are the causes that make promotion of cold energy utilisation difficult. It will be easier for new LNG receiving terminals to reap the benefits of cold energy utilisation if potential applications are taken into consideration during the planning stage, together with co-ordinated government policies and industrial chain participation.

It is worth noting that LNG’s cold energy utilisation also faces many restrictions, for example: the length of LNG pipelines must be controlled within 1 - 2 km due to safety considerations and regional restrictions; the stability of cold energy supply could be impacted by the LNG demand in different seasons; the available piping insulation and cold storage technology.

LNG receiving terminal expansion work

Considering factors such as high construction cost, constructability, shipping, and environmental impacts, the overall maritime construction works of LNG receiving terminals are usually completed during the newly-built period. However, the owners would reserve enough space in accordance with their investment plans for further expansion of LNG storage tanks and regasification facilities stage by stage. In contrast to newly-built LNG receiving terminals, the expansion work pays more attention to the integration between expanded facilities and existing facilities, especially the control rooms, power supplies, fire protection, isolation and leakage of mechanical works, and location of electrical and instrument (E&I) tie-in points. The system and equipment capacity of existing terminals also needs to be verified.

Conclusion

In the long-term, Asia’s growing LNG demand forecast will motivate existing import countries as well as newcomers to increase their capacity, either through expansion or building new LNG receiving terminals.

Although LNG receiving terminals are not as complicated as liquefaction terminals in terms of engineering complexity, investors nevertheless must think carefully about some important issues before investing in LNG receiving terminal constructions. These include: ensuring the safety of terminal construction; reducing environmental impact from construction activities; gaining the support of environmental protection groups; obtaining government permits; promoting cold energy utilisation via the synergy of government policies as well as industrial participation; and allowing facility access to the public to get their support on clean energy.