LMS 18.3.2 Deployed at LNG Site in Virginia
December 2022
MHT Technology’s LMS 18.3.2 software was deployed at the TC Energy site in Chesapeake, Virginia in December 2022. The deployment took place as part of an upgrade of their software and included the scheduled rollover feature and the new associated automatic composition facility.
TC Energy were already using 18.2.5 to monitor the stratification of their LNG storage tank, but decided to upgrade their software following a training program on the subject of LNG Rollover. The peak shaving plant in Chesapeake stores excess natural gas during the summer months when demand is low, to provide back to the national grid in the winter. In the change over from exporting to importing gas the tank contents can weather to leave a dense heel in the tank, setting up the conditions for stratification and eventual rollover.
ROLLOVER Protection
The automation starts with a scheduled profile of the tank. The Scientific Instruments 6290 gauge is sent a command by LMS to do a full profile of the tank contents. The second stage of the analysis takes place after the profile is completed; a rollover calculation takes the last 2 profiles and analyses them for stratification. If both are stratified the system is then able to compute the rate of change between the two and estimate from that, the time taken for the stratification to break down and result in a rollover event.
FULLY AUTOMATED ROLLOVER MONITORING
Alarms are used to alert operators to the tanks’ status. Keeping them informed of tank stratification and any forecasted rollover events. Additionally, a simplified user interface graphically summarises the tanks’ status.
COMMISSIONING AND TRAINING
MHT Technology flew an engineer to site to assist with the commissioning process and provided a demo system free of charge to allow staff to practice with the software as thankfully rollover events are uncommon occurrences. Like fire drills, you need to practice them, in the hope that you never need to use them.
