Viscometer Helps the Oil Flow

An on-line viscometer from Hydramotion (UK) Ltd is helping to keep the oil flowing at a major North American refinery.

Installed directly in the process line at the company’s integrated crude topping/vacuum distillation unit, the Hydramotion XL7-152 intrinsically safe viscometer is monitoring atmospheric tower bottoms at
temperatures up to 365°C (690°F). With the XL7 providing continuous, real-time viscosity data, engineers can immediately make the adjustments they need to keep the pumps turning.

The company chose the XL7-152 because it is certified to EEx ‘ia’ IIC T4 for use in Zone 0 Hazardous Areas (Class 1 Div 1 Group A) — more than adequate for the plant environment — while combining unmatched ease
of use with high sensitivity and excellent repeatability at the low viscosities involved (less than 50 centipoise). As the transducer is designed to dissipate heat, no special cooling was required despite the high temperatures.

The chances of corrosion were minimised by using Hastelloy® C276 for all wetted parts. Supplied with any process fitting, the XL7 probe is an all-welded construction which can be mounted in the full fluid flow in any orientation, with no need for any ancillary pipework. Not only does this simplify installation, it also eliminates inaccuracies arising from localised temperature differences or atypical measurement conditions.

The XL7 viscometer is a rugged, field-hardened device that measures any viscosity range at temperatures up to 500°C in tanks or pipes of any capacity. The digital read-out unit can be mounted up to 1000 metres
from the transducer, and Hydramotion will even supply a suitable IS barrier on request.

Unaffected by flow rate or bubbles (“slugs”) of air or gas, and with no moving parts to wear out or fail in service, the XL7 is a “bolt-on-and-go” device requiring no on-site calibration and virtually no maintenance. This makes it ideal for oilfield or refinery applications where removal or replacement of the device would be costly, inconvenient or impractical.