TOP Gas

The relatively plentiful supply of gas combined with the environmental advantages over competing fuels in many situations is affecting the development of a suitable energy distribution infrastructure. In the context of the gas industry infrastructure materials technology focuses primarily on pipe construction materials and processes which allow the provision of pipe capacity at lower capital and/or operating cost. There is a wide diversity of ways in which materials technology can and will impact on the management of the energy infrastructure such as gas transmission network.

Impact of Moleculary-scale Materials Technology

Gas Distribution

Gas Distribution

Natural gas is transported around the country through a network of high pressure pipelines (typically 25 to 70 bar) which form the national gas grid. A network of lower pressure pipes (below 10 bar) takes the gas from the grid to the consumer.

High Strength Steel Pipes
Increasing the material’s yield strength allows the designer two options: either to increase the operating pressure and deliver more throughput without increasing the diameter or wall thickness; or to keep the throughput constant while reducing the diameter and wall thickness. Both reduce the tonnage of steel needed for the amount of gas transported. High strength, combined with good toughness and weldability, has been achieved through careful refinement of the thermo-mechanical processes during plate rolling to form the pipe, particularly the introduction of spray cooling after rolling, combined with more sophisticated use of micro alloying additions to the steel chemistry.

Reinforced Thermoplastic Pipes
Reinforced thermoplastic pipe (RTP) is particularly attractive for extracting remote gas or oil reserves. The material’s light weight significantly reduces transportation costs and installation times and allows easier pipe laying in areas with difficult access such as mountainous or soft-soil locations, or environmentally sensitive situations where impact of heavy excavation and transport vehicles must be minimized.The chemical inertness of polyethylene allows the transport of corrosive gas and/or liquids so minimizing the need for well-head treatment. It also eliminates the need for pipe coating and cathodic protection against external corrosion. The photo shows a line of RTP manufactured by Tubes D’Aquitaine being installed to transport gas in Siberia.

RTP is made from a composite material. The pipe is manufactured by over-wrapping a polyethylene cylindrical liner with a high strength fibre reinforced tape; an outer polyethylene layer is then extruded over the reinforced surface to protect the fibres from damage. The development of novel joining technology for these pipes allows installation speeds up to eight times faster than for steel pipes. The  photo shows a cut-away of the RTP designed and manufactured by Tubes D’Aquitaine.

Low Pressure Pipes
Polyetheylene (PE) has been used in gas distribution pipes in the UK for 30 years. Pipes range from 16 to 800 mm diameter. PE is used because of its high stress crack resistance, good strength, corrosion resistance and excellent heat fusion welding characteristics. PE is more tolerant of ground conditions and enables installation of a continuous all welded leak-free system by the use of but fusion and electrofusion joints. Cost benefits are due to speedier installation with less need for excavation and disruption to traffic and the general public.

PE is widely used for trenchless relining of old iron and steel gas pipes, necessitating novel operational methods and ways of working. The cost effectiveness of PE pipes has enabled gas supplies to be extended to rural communities.

Impact of Moleculary-scale Materials Technology
Major developments are taking place in the design and low-cost manufacture of molecular-scale materials. These are enabling the production of low-cost microchips incorporating specific functional capability for a wider range of physical, electromagnetic and chemical measurements for micro-devices such as pressure, temperature and flow sensors, and gas detectors. When combined with the parallel developments in precision micro-engineering, IT and communications, these technologies offer the potential for a wide range of devices for monitoring, controlling and managing energy distribution networks.

Functional materials with molecular-scale design are also leading to advanced catalysts, membranes and ‘active surface’ materials which have applications in fuel cells and other small-scale energy conversion devices. The development of highly compact gas reformers, the conversion of methane to hydrogen and the development of carbon-based high density hydrogen storage systems will offer the potential for significant further moves towards high-efficiency distributed energy conversion with minimal environmental impact. The picture shows a crystal structure of zeolite used for separating carbon dioxide from natural gas.

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