Tank Farm Level Monitoring

The designs of tank farm level detectors include (1) wire-guided float, (2) servo-operated float, (3) surface detector (plumb-bob), (4) radiation backscatter, (5) radar, (6) HTG, and (7) hybrid gauges. Their ranges go up to 60 m (200 ft). 

Hydrogen tank farms will require the same types of inventory controls and level monitoring as do liquefied natural gas (LNG) and oil tank farms 

In custody transfer of full or nearly full tank volumes, manual gauging is still practiced in the United States, whereas ATGs are preferred in Europe. In either case, the inherent tank accuracy is a factor, because the filling of a large tank causes the bottom to sink, the shell to bulge, and the top to sink, and changes in temperature also cause changes in tank dimensions. 

Automatic tank-gauging systems are found in almost all tank farms for inventory monitoring. The wire-guided float tape gauge systems are most 

Type of Design Approx. Number in Use in United States Cost (for 40-ft Floating Roof Tank with Temperature Measurement) Measures Accuracy Maintenance Required 

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Table I is a typical daily operating report for the NFS Waste Tank Farm. It shows that temperatures, densities, liquid levels, air flow rates, etc. are observed and recorded at least three times a day. Any equipment malfunction or response to the continuously monitored alarms is reported at least once a day on a supervisor s summary report. With the required initialing of both the operator and the supervisor on each shift, at least six trained individuals are made aware of the operating status of the facilities daily. In addition, these daily reports are distributed to no less than four other responsible members of management for information and review.

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