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The Sentech Level Profiler allows operators to "see through the walls" of separators and vessels

Floaters, visual gauges, DP and guided wave radar level transmitters have since long served their purpose

in light, sweet crudes and generally when water separates easily from oil. Heavier and more viscous crude

oils, however, introduce much more complex and less defined levels in production separators.

When making efforts to improve separation with tight emulsions, long settling times and severe foaming,

it is vital for an operator to promptly learn whether the actions are effective or not.

The Sentech Level Profiler allows operators to "see through the walls" of the separator, by providing:

• Location of water, emulsion, oil, foam and free gas layers relative to weir plate

• Gradient color for varying water cut across emulsion layer

• Customization of vertical resolution to suit process conditions and customer requirements

• Optimization of resolution at critical levels in separator (e.g. just below top of weir plate)

• Optional flushing capability for effective cleaning of sensors without affecting production

The Sentech Level Profiler offers all these benefits without the need for any radioactive isotopes.

Typical Applications

Beyond conventional production separators, other applications for the Sentech Level Profiler include:

• Horizontal and vertical Free Water Knockout drums/vessels – to reduce downstream water load

• Mechanical and electrical coalescers – to increase efficiency and throughput

• Heater treaters – the Sentech Level Profiler can be supplied for temperatures up to 225°C

• Storage tanks – to determine level of residual water gathered at the bottom of the tank

SENTECH LEVEL PROFILER

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Measurement Principle

The Sentech Level Profiler uses a series of SeCaP sensors on a vertical rod

to accurately determine the fluids from top to bottom of the separator.

The single electrode capacitance sensor provides a calibrated value from 0

(in gas) to 1000 (in produced water). Foam, oil and emulsions generate

values between these extremes, and also allows the Sentech Level Profiler

to reveal differences in water concentration across any emulsion layer. As

the sensor measures the electric properties and not the density of the

fluids, it works equally well when the density of oil is equal to that of water.

The number of SeCaP sensors is adapted to separator size, process

conditions and customer preference. A vertical resolution of 1 cm can be

achieved by installing sensors in spiral pattern on the profiler rod, although

such high resolution is rarely required.

Optional Sensor Cleaning System

Every SeCaP sensor undergoes three weeks of burn-in at 1600°C to close all

porosities in the ceramic surface. This prevents absorption and adhesion of

both hydrocarbons, water and solids. However, in heavy oil applications,

when wax, asphaltenes, resins and fine solids deposit on all surfaces inside

the separator, the surface of the SeCaP sensors is also exposed.

The Sentech Level Profiler is able to detect build-up of contamination on

the sensors, but software can never remove the dirt and grease that

separates the sensors from the fluids that they are trying to detect.

For such fields, Sentech AS has developed an integrated cleaning system,

which allows simultaneous high pressure jet flushing of all sensors through

permanently installed nozzles – without having to retrieve the Level Profiler

rod – and without having to interrupt production.

A SeCaP sensor ceramic surface

coated with asphaltic wax

(specific gravity of 0.91) before

and after cleaning with

Sentech AS integrated high

pressure jet flushing system High pressure flushing nozzles and pumping system. The flushing skid is controlled directly

from the DCS and is completely disconnected from the Level Profiler measurement system.

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System and Installation

The Sentech Level Profiler is certified as an Ex ia system from Hazardous Area to Safe Area.

A full Sentech Level Profiler system consists of the following components:

• Profiler rod with SeCaP sensors, oscillator and temperature sensor (in Hazardous Area)

• Controller Unit in separate enclosure, NEMA 4X (in Hazardous Area, max. 5 m from meter body)

• Analyzer Interface cabinet, NEMA 12 (in Safe Area) with barriers for power and communication

The barriers in the Safe Area Interface cabinet are required to maintain validity of the Ex-ia certificate.

Sentech Analyzer Software

The Sentech Level Profiler software uses the RS-485 connection to read data from all the sensors typically

once every second. Each sensor is presented as a bar with its unique color and length, according to the

measured SeCaP values (between 0–1000). The bars stack up to provide a true real-time representation

of the levels in the separator. In addition, the software also stores and presents the Level Profile trend,

allowing operators to go back in time to study particular upset conditions.

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Sentech Level Profiler datasheet

The specifications below apply for the traditional Sentech Level Profiler design with no flushing system.

The table indicates the standard options for material, sizes and process connections.

For other specifications and details on flushing system and skid, contact Sentech AS (info@sentech.no).

MECHANICAL SPECIFICATIONS – PROFILER ROD

Rod diameter & length 80 mm OD (typ.), max. 30 m for one profiler rod (vertical)

Material SS 316L

Construction Machined sections up to 3.5 m, bolted together in situ for longer rods

Process connection Flanged, minimum 4" ANSI/API, 150# - 900#, RF/RTJ

Wetted parts SS 316L, Ceramic

Number of sensors Selected by customer based on separator height and required resolution

Design temperature 125°C, 175°C, 225°C

Design pressure Up to 450 bar (depending on process connection pressure rating)

Enclosure protection IP66 (profiler rod terminals housing)

Protective coating Not applicable

MECHANICAL SPECIFICATIONS – CONTROLLER UNIT ENCLOSURE

Dimensions 375 x 265 x 108 mm3 (14.8" x 10.4" x 4.3")

Material SS 316L

Mounting Stand-alone

Enclosure protection IP66/IP67

Protective coating Not applicable

ELECTRICAL SPECIFICATIONS

Hazardous Area classification

Ex ia protection from Sensor Unit to Safe Area Analyzer Interface cabinet Profiler rod (Sensor Unit): ATEX/IECEx II 1/(1)G Ex ia/[Ex ia] IIB T4-T2 Ga Controller Unit enclosure: ATEX/IECEx Ex ia IIB T4 Ga -40°C ≤ Ta ≤ +60°C Analyzer Interface cabinet: Must be placed in Safe Area

Ambient temperature -40 to 60°C

Outputs RS485 Modbus RTU, 4–20 mA (e.g. for oil/water interface level & alarm)

External power supply 120/230VAC, 24VDC to Safe Area Analyzer Interface cabinet

Safe Area power barrier Pepperl & Fuchs KFD0-SD2-Ex1.10100 (mandatory for Ex ia certificate)

Power consumption < 10 W

Cable entry Profiler rod terminals housing: Amphenol (factory-connected IS cable) Controller Unit enclosure: Amphenol (factory-connected IS cable) + M20

Maximum cable length Profiler rod to Controller Unit enclosure: 5 m Controller Unit to Safe Area barrier modules: 700 m

PERFORMANCE SPECIFICATIONS

Primary measurement Water, emulsion, oil, foam & gas profile (Modbus RTU serial output) Water level (% or mm) (4–20 mA output)

Measurement principle Single Electrode Capacitance

Measurement range Defined by profiler rod Active Measurement Section length

Number of sensors Selected by customer based on separator height and required resolution

Profile resolution Defined by Active Measurement Section length / Number of sensors

Sensitivity Each sensor can distinguish between water, emulsion (incl. varying water content across emulsion layer), oil, foam and gas