AvantiGas Engineering Manager Stephen Hallett is asked to assess the potential of LNG for UK industry: part three

For the final instalment, Stephen focuses on the technical characteristics of LNG and highlights installation considerations.

In the first two articles in this series, Stephen Hallett looked at what LNG is and its potential use for off-gas grid businesses, how oversupply in the market has brought lower prices, and the environmental and cost benefits that tie in with recent UK Government legislation targeting carbon emissions.

But what does a business need to think about when looking into an LNG installation as a possible fuel solution?

AvantiGas Engineering Manager Stephen Hallett says: “Factors to consider include storage area, site layout, access for fuel deliveries, volume of gas required and frequency of use, as well as the specific application that the gas will be used for. Every business is unique and often an energy solution will be a bespoke installation.

“From a technical perspective, the key engineering challenge is that LNG is a cryogen (cryogenic liquids are typically liquefied gases at -150°C or lower) and this presents storage challenges. In industrial applications (where specified gas conditions are not critical to operation) you’ve got to keep the product as cold as you can for as long as you can. You need to use special materials – carbon steel becomes brittle when very cold, so you have to use stainless steel pipework and fittings, which is more expensive.

“LNG vessel orientation may be different to LPG (Liquid Petroleum Gas) as both horizontal and vertical LNG vessels are available. There’s little difference as both are certified and safe to use, but vertical tanks take up less space. Spherical vessels may also be used for very large air separation cryogenic units.”

Vessels used for LNG storage are much like a typical ‘Thermos-style’ flask. They consist of an internal vessel storing the product, which is surrounded by insulation under vacuum, with an external shell to hold it all together. They range from around 1000 litres to up to 100 000 litres in volume.

Steve again: “For industrial supply schemes, the inner vessel will typically be stainless steel, and the outer may be stainless or carbon steel. The design of these vessels should minimise the amount of thermal transfer between inner vessel and outer vessel/shell. An insulation material called perlite is often used along with a vacuum to prevent heat transfer – the vacuum improves the efficiency of the perlite as an insulator.”

If you are using LNG as a gas rather than as a liquid, and if you’re putting it into either a commercial or domestic property, the Gas Act says it must be odorised to make leaks more easily detectable. But AvantiGas doesn’t like to leave anything to chance. Says Steve: “All our LNG installations will have active gas detection – it is more reliable than people. The odorant typically used to give the gas a smell becomes solid at cryogenic temperatures, so it must be added on site, at the point of use.”

“The vast majority of LNG installations will require hazardous consent in some form unless they’re quite small operations. In terms of planning for LNG, hazardous consent is required when storing 15 t or more, compared with LPG at 25 t. If you exceed 50 t of storage on site, lower tier COMAH (Control of Major Accident Hazards) consent is required and the associated Major Accident Prevention Plan (MAPP) must be submitted and reviewed with the Health and Safety Executive (HSE). Upper tier COMAH consent is required if exceeding 200 t.”

Any LNG installation provided by AvantiGas will come with an operator’s manual and training on how to use it.

On capital expenditure, the important thing to remember is the long-term return on investment. Steve again: “The CAPEX cost of an LNG installation is currently higher than other options, but the savings from the commodity price of the gas can outweigh the initial investment cost over time. Coupled with the carbon benefits, LNG is increasingly seen as a cost-effective solution by businesses which are off the mains gas grid. For these businesses, choosing an efficient yet reliable energy source is critical. As one of the UK’s major off-grid energy suppliers, AvantiGas will find the right energy solution for your business, whether that be LNG, LPG or renewables."

To read part one and two please follow the links at the beginning of the article.

Read the article online at: https://www.lngindustry.com/special-reports/04122017/avantigas-engineering-manager-stephen-hallett-is-asked-to-assess-the-potential-of-lng-for-uk-industry-part-three/