Maximising the availability and performance of LNG plants to ensure overall profitability is key challenge for LNG operators.

The combination of complex equipment, multiple recycles, high degree of integration and process dynamics present unique challenges for model-based optimisation.

PSE, via its gPROMS software and consulting services, provides advanced capabilities that deliver benefits such as increased throughput through higher availability, reduced energy costs and rapid response to abnormal situations.

PSE and gPROMS advantages

PSE’s gPROMS technology has several key advantages – in particular its optimisation capabilities, coupled with the ability to handle complex recycles rapidly and robustly – that are the reason for it being used for a large proportion of the world’s LNG plant modelling.

LNG process flowsheet in gPROMS ProcessBuilder

In addition, PSE’s Consulting and Process Safety services can provide rapid expert solutions to help increase availability and optimize day-to-day production.

Increase LNG plant availability

Some two-thirds of the lost availability is due to unscheduled shutdowns or unit trips, and further time is lost on unoptimised start-ups. Key to increasing availability is to extend no-touch times and optimise restart.

Avoid shutdowns via extended no-touch

A dynamic flare analysis can identify additional time available, effectively widening the “No touch time” for liquefaction unit and delaying the start of the plant depressurisation operation. This increases the potential for a cold restart of the plant, avoiding the more expensive depressurisation and warm restart.

For example, a review of the flare capacity of a large Australian LNG facility found that in the event of total power failure, the operator will have 35 minutes to restore power before it is necessary to depressure the plant.

Optimise restart of liquefaction plant

Manual start-up of LNG liquefaction units can be unnecessarily time-consuming, leading to reduced plant availability and large CO2 emissions.

gPROMS’s advanced dynamic optimisation tools can determine the minimum cooldown time required to bring the LNG liquefaction plant to full production, potentially reducing start-up time by up to 5 hours.

Offline and online optimisation of LNG plants

PSE can provide sophisticated optimisation models behind web-based interfaces, enabling Operations to optimise day-to-day LNG production depending on current prices, equipment availability, prevailing weather and other factors.

Such an optimisation model also provides a rapid response to abnormal situations.

We can also package LNG plant models for execution within the plant automation system or behind easy-to-use custom dashboards as online operatory advisory tools for Engineers and Operators.