On-line Side Stream Oil in Water Analyser - Model OIW-EX 100 or OIW-EX 1000

Transcription

1 brochure On-line Side Stream Oil in Water Analyser - Model OIW-EX 100 or OIW-EX 1000 Advanced Sensors Ltd Oil in Water Analyser System known as the OIW-EX100 or OIW-EX The system is designed to monitor the residual hydrocarbon content of pipelines carrying produced water at oil production facilities and refineries etc. The OIW-EX100 uses laser radiation to energise the contents of the measurement chamber with an incident optical wavelength. A sensitive tuned detector at a different wavelength is then used to measure the stimulated fluorescence value. This fluorescence value is used to determine the proportion of hydrocarbons within the chamber. The measurement technique incorporated in the Advanced Sensor s monitors is laser induced fluorescence. The transducer sensor head is a patented, combined Optical and Ultrasonic component. Water passes through a measurement chamber (300mL), within the chamber there is a small sapphire window used for measurement and a larger sapphire window for viewing the inside of the chamber. The laser passes through the smaller sapphire window to excite the water sample, the fluorescent properties are captured via Optical fibre light guides and taken to: OIW EX100: An optical filter and photo multiplier tube (PMT), the optical filter selected depends on the wavelength properties in the water; OIW EX1000: An optical UV spectrometer. The spectrometer takes the optical fingerprint of the oil, should the oiltype change, the analyser will automatically detect the change and select the appropriate calibration file to provide consistently accurate measurement. This feature is unique to Advanced Sensors analysers. Ultrasonics The Ultrasonic transducer performs 2 functions: It cleans the sapphire windows ensuring that measurements do not deteriorate; It periodically homogenizes the sample to correct for oil droplet size variation. Spectrometer The in-built UV spectrometer (EX1000 only) scans the water every 10 minutes and files the results for 10 years for future investigation. The spectrometer is of great value when detailed analysis of water content is required. An installed unit was periodically reporting higher OIW concentration results than the field laboratory that used solvent extraction and IR detection. The spectrometer logs were examined during this event, and the spectra indicated the presence in the water of an interferent other than oil. Further tests were performed, and the substance causing the anomaly was identified. This led to the selection of a new wavelength range and an optical filter that was fitted to the PMT, thereby eliminating the interference. Whilst chemicals can be evaluated in the Advanced Sensors Laboratory and isolated before the monitors are delivered, the in-built spectrometer facilitates the evaluation and analysis of new chemicals or additives being introduced to the process. Operating dynamic range The dynamic range of most OIW monitors is limited to 500 ppm or a maximum of 1000 ppm TPH. The standard EX100/1000 can operate up to 3000 ppm TPH. The EX1000Advance has a direct fluorescent dynamic range of ppm OIW without any extrapolation. In the figure (right), the direct fluorescent curve for 0 to ppm OIW without any extrapolation. After ppm, the instrument flat-lines. The flat-lining in itself is a new development, traditionally as oil levels increase the fluorescence flat-lines and then falls, this can confuse an instrument in believing the oil content is falling when it is actually rising. The extended range monitor EX1000 Advance facilitates the monitoring the efficiency of separators and hydro-cyclones, providing a greater insight to process dynamics. Oil In Water (OIW) monitor schematic Spectrophotometric scan of water, chemical and chemically-treated water (y-axis intensity; x-axis wavelength, nm.) Fluoresence scan / range

2 Features The Advanced Sensors OIW monitors are continuous, on-line, selfcleaning UV fluorescence detection systems. Advantages of this laser fluorescence system for monitoring OIW are many: Instead of the laser or light source having to pass across a pipe to a detector, the requirement to completely flow photons through moving water is eliminated. With the Advanced Sensors flow through cell the light source and detector with the specially coated sapphire window detects all Total Petroleum Hydrocarbons (TPH) or Oil and Grease (O&G) in the chamber. The ultrasonic beam not only homogenizes the sample in the chamber, but also cleans the sapphire window. In the presence of sticky precipitates or from soapy emulsions, ultrasonics maintains a clean window. In the homogenization zone, and when the chamber is briefly closed, the powerful sonication churns up the oil into a homogeneous mixture with a relatively uniform standard droplet size distribution. This eliminates the need for particle or droplet counting in water systems where fluids may be highly variable in composition, quality and flow rate. The Advanced Sensors technology is able to cope with system upsets, well flow variations, and solids. The homogenization mode is especially applicable to sour systems where oil coated iron sulphide solids may be present in suspension or in emulsions. For each application of this technology, UV fluorescence signatures may be obtained so that the bandwidth is specific only to dispersed oil. When chemical additives are present that overlap with the oil bandwidth, Advanced Sensors professionals are able to remotely squeeze the bandwidth tighter to ensure that the output signal is focused on oil alone. The standard communication interfaces are 4-20mA, Ethernet and ADSL (2 wire Ethernet), wireless is available as an option. The 4-20 ma is for connection to the Control room (DCS) and the Ethernet and ADSL is for connection to the company s intranet. The intranet/ internet connection facilitates the connectivity to the instrument form other company locations or the advanced sensors laboratory for further diagnostic and analysis support. Data logs. PPM measurements are stored every second in daily logs as excel files, the daily logs are stored for 10 year on the instrument. The spectrometer s scans are run every 10 minutes and excel logs are also stored for 10years on the instrument. Software is provided to interrogate both data logs (LogView) and Spectrometer Logs (Span). Both LogView and Span can be utilized remotely, the software will reach down to the Monitor and extract the selected filed for investigation. Alarm levels may be set for trending or operator attention to the water treatment and processing system. The unit can also manage multiple streams to the instrument, controlling a valve on each stream. Each steam can be easily scheduled in order and duration of flow.

3 Sample valve is open Sample flows continuously through the sample chamber Oil will contaminate the sapphire window The ultrasonic transducer is activated and switched on The sapphire window starts to vibrate Oil contamination and particles are removed from the sapphire window and flushed out The sample valve closed. No sample flows through the sample chamber The sample chamber now is isolated The ultrasonic transducer is switched on. Ultrasonic homogenisation takes place. Accuracy is guarantied by homogenising the sample containing oil The laser excites oil in water Oil fluorescence captured and measured Oil in water being measured by measuring the intensity of the fluorescence The sample valve opens Analysed Oil concentration is presented on screen and outputs and stored

4 Sample chamber, sapphire window, laser and ultrasonic transducer There are many references using the Oil In Water analyser model OIW EX100/1000 Screens, parameter Settings and Configuration and remote Access Many correlation studies are done

5 Analyser OIW EX 100/1000 Analytical principle Range Accuracy +/- 1% Repeatability 1% Operating ambient temperature Operating conditions for sample Sample flow (minimum / norm / maximum) Sample temperature (minimum / maximum) Sample pressure (mini / maxi) Response time Cycle time Weight Footprint (W x D) UV Fluorescence Class 3 industrial Laser; selective optical filter and photo multiplier detector Model EX 1000 with real time spectrometer 3000 ppm Standard ( ppm enhanced) -15 ºC. to 80 ºC. No flow control or pressure regulation required 5 / 20 / 100 ltr/min ºC bar (0-174 psi); Extended pressure range bar ( psi) < 1 second Continuous Approx 79 Kg (enclosure plus measurement chamber, stand & valve) Type and Qty of signal 4-20 ma Galvanic isolation (free from earth) / 1 Interface Power supply Power Consumption Internal Data Logging Tropicalized Electrical area classification certificate / N Standards Enclosure rating CALIBRATION Required Instrument Air Sample Conditioning System Diameter of pipes Fitted with a sample take off for lab. / location. Operational Notes Model EX 1000; Spectrometer Specifications On-line Side Stream Oil in Water Analyser - Model OIW-EX 100 or OIW-EX x 640 mm It is recommended 500 mm be maintained at the front and rear of the unit for user access ma / Ethernet / RS232 & 2-wire ADSL (HART optional) 110 or 230 VAC, 50 or 60 Hz < 300W at maximum draw. ~ 60W in normal conditions. >10 years Yes ATEX Ex d II 2 G Ex d IIB T4 EN :2001 Safety requirements for electrical equipment for measurement, control and laboratory use UL Class 1 Div 1 IMO Approval to MEPC 107(49) US Coast Guard Type Approval CRN s for Canadian provinces Ingress Protection IP65 Annual Inspection 4 bar; only used for operating the pneumatic sample valve. Integrated Ultrasonic Transducer 1" 316L 150lb RF ANSI Standard. Alternatives available on request Yes Self cleaning No small pipes Independent of turbidity or bubbles Viewing window in sample chamber. Large sample chamber 300 ml. Network multiple units to Control Centre Integration time: 1 ms -10 seconds Measuring range: nm Dynamic range: 2 x 10 8 Sensitivity: 3 x watts / 1-second integration Signal/noise / Dark noise 250:1 (at full signal) / 50 (RMS) Resolution: 1,5 nm Stray light: < 0,05% at 600 nm

6 Specifications are subject to change by manufacturer or ODS without notice due to modifications or improvements revision: