refining

Permasense delivers data that enables safer, more profitable operations.

Please watch the following video, expliaing the use and benefits of the WT sensor system in refineries:

The system has a wide range of applications in oil refineries. Deployments are typically in

  • areas of known concern, such as pipework operating outside of design specification - for example in connection with feed changes, on elbows, and areas of particular turbulence
  • areas that cannot be inspected sufficiently frequently, for reason of costs of access, such as crude overhead lines, or of hazard to inspection staff due to high metalwork temperatures

Sensors are installed throughout the refinery including: crude units (CDU), vacuum units (VDU); amine units, alkylation units, cokers, cracking units (FCC, hydrocrackers); hydrotreaters, sour water strippers – including on distillation column walls, stripper towers, inlets, outlets, and transfer lines (including reducers and elbows); air coolers – header boxes, inlets and outlets, heat exchanger casings, inlets/outlets; pump inlets/outlets; furnaces – inlets, outlets, U-bends, transfer lines, tower walls.

Sensors are now in service on a full range of materials including carbon and cast carbon steel, P5/5 chrome, P9/9 chrome, 1% Cr (5130), duplex, P265GH (430-161), 1.4571 (316Ti), P2

95GH (17Mn4), monel, HR120, Inconel, Incoloy and hastelloy.

Drivers for adoption include:

• Tighter and more frequent corrosion monitoring in critical areas of the plant
• Feedstock diversification, especially processing of higher acidity crudes
• Measurement accuracy, frequency and efficiency
• Monitoring of corrosion inhibitor efficiency
• Inspector safety
• Early detection of changes in corrosion rates
• Informing shutdown timing decisions
• Informing metallurgical upgrade decisions

 

White papers 

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Corrosion monitoring solutions for hydroprocessing units

Corrosion monitoring solution for sour water stripping units

Corrosion monitoring solution for amine units

Continuous remote corrosion monitoring drives environmental compliance for jetty operations

Comparison of corrosion monitoring systems 

Continuous naphthenic acid corrosion monitoring adds crude slate flexibility

Corrosion monitoring solution for HF alkylation units 

Continuous corrosion monitoring of crude overhead systems

 

Case study -  Gelsenkirchen experience

Corrosion monitoring was conducted on cast carbon steel u-bends with a wall thickness of approx. 25mm (1 in.), operating at 380°C (720°F) in the Gelsenkirchen refinery operated by BP to ensure continued safe operation. Because the high temperature prevented accurate manual ultrasonic wall thickness measurement, and would have exposed inspectors to significant hazard, the Permasense continuous monitoring system was installed: this secured operation with confidence until turnaround. The system has been delivering reliable measurement data for over four years now.

 

 

 

Case study - Feedstock diversification, especially processing of higher acidity crudes

'The world is running low on lightweight high-quality crudes. As a result, refiners are increasingly looking at heavier oils which require new approaches to processing' (President Robert Trout quoted in Hydrocarbon Publishing Weekly Refining Digest, March)

Permasense monitoring systems are forming a key element of refiners' ability to process these heavier oils.

A European client processed a test batch of a new crude for a one month period, making up approximately 20% of the total feedstock to the tower. Sensor data from the gasoil draw quickly demonstrated an accelerated corrosion rate during the test period, with consequent loss of over 4% wall thickness in one month, equivalent to 6.8 mm/year. The higher corrosion activity highlighted by the Permasense sensor data resulting from processing this crude is enabling the client to determine an optimum inhibition strategy and to set processing limitations for the crude to enable maximisation of profitability, while ensuring that the equipment will perform safely until the next turnaround.

 

 

Case study - Tighter and more frequent corrosion monitoring in critical areas of the plant

Sensors have also been installed within sour water strippers at high corrosion risk locations in the overheads. In one example, corrosion rates shown by the sensors were running steadily at 2 mm/year (14% of the initial wall thickness per year). By re-optimising process conditions, the operators were able to bring the corrosion rate completely under control, as shown by the sensor data below.

 

Case study - Monitoring of corrosion inhibitor efficiency

Other refiners are using corrosion rate data from the Permasense sensors to optimise corrosion inhibitor injection rates. In the example below, operators adjusted inhibitor dosage over the period of August and September until the corrosion rate shown on the sensor was seen to have stabilised.
Continuous ultrasonic wall thickness measurement is being used in real time to understand the commercial opportunities available from tighter and more reliable monitoring of corrosion and erosion rates in critical parts of the installation, and when combined with wireless transmission can bring significant value as well as cost, safety and environmental benefits to operators. There are now over 4,500 sensors installed in both upstream, midstream and downstream oil and gas facilities and power plants around the world.

 

Case study - Improved insight into the impact of feedstock decisions

Processing of high acid 'opportunity' crudes is a key profit improvement strategy for many refiners in the Western Hemisphere. While naphthenic acid corrosion tends to be quite localised, Permasense is seeing refiners deploying arrays of sensors, making a series of point measurements to highlight where a significant increase in corrosion activity is being observed. This approach also enables an understanding of the effectiveness of inhibitor chemical injections in the 'at risk' locations.

 

An example of such sensor arrays is shown above - the sensors are installed circumferentially across five locations along a crude or vacuum heater transfer line. Data from the Permasense system can give the refiner confidence to gradually increase the acidity of the crude oil processed while closely monitoring 'known-risk' areas for an increase in corrosion activity.


Case study - Informing metallurgical upgrade decisions

Another refiner installed Permasense sensors eighteen months before a major turnaround so that they could track corrosion over a one year period through the crude tower and associated pipework. The objective was to better understand the dominant corrosion mechanism - either uniform thinning corrosion from sulphidation or localised attack from naphthenic acids. The output would inform their decision making process to determine the preferred metallurgy to be used to upgrade the equipment.
The sensor data demonstrated that localised corrosion from naphthenic acid attack was the dominant mechanism and as a result the refinery selected the appropriate metallurgy to be installed in the upcoming shutdown.