Introduction
Oil and gas temperature points include pipelines, compressor equipment, separators, storage systems and refinery process vessels. Start by defining exactly where temperature is needed, the normal and upset process temperatures, and the fluid or atmosphere contacting the sensor.
For a process connection or protective assembly, provide design pressure and flow information where relevant, along with mounting details, instrument input and any classified-area requirements. These details guide selection of the sensor construction, materials and electrical arrangement.
Process Context
Upstream measurement points may be at wellheads, separators or produced-fluid systems; midstream points include pipelines, metering systems and compressor stations. In refineries, columns, reactors, heat exchangers, tanks and steam utilities each present different temperatures, mounting arrangements and process conditions.
Where a point is in a classified area, use the site's area classification to identify the required protection concept, equipment marking, temperature class, gas group and installation method. Include these requirements with the sensor and instrument input details when planning the installation.
Selection Guidance
At a point using a thermowell or other protective fitting, define the process temperature, design pressure, flow conditions and connection details so the pressure-boundary and mechanical design can be assessed. For sour service, identify the fluid chemistry and project material requirements, including any applicable ISO 15156 review.
Choose the sensing type and construction against the required temperature range, response, instrument input and maintenance approach. Specify mounting, head or transmitter arrangement, cable entry and classified-area requirements as part of the installation design.
Recommended Sensors
Heavy-Duty Flanged Thermowell Assemblies
For a flanged process point, document the connection, operating temperature, design pressure and flow conditions for the responsible mechanical design review.
Multi-Point Reactor Profilers
For reactor profiling, define the required measurement locations, temperature range, available nozzle or mounting arrangement and instrument inputs.
Assemblies for Classified-Area Designs
Provide the site's area classification and required protection concept, then identify the sensor, instrument and installation requirements for review.
Installation Considerations
For an inserted assembly exposed to process flow, provide fluid properties, operating temperature, design pressure, flow or velocity data and proposed geometry for mechanical evaluation, including wake-frequency assessment where applicable. Mounting location, insertion depth and any protective fitting also affect the measurement and should be defined at the point of selection.
For classified locations, plan the sensor, instrument input, head or transmitter, cable entry and installation method against the site's area classification and project requirements. Include the required equipment markings and wiring or barrier details in the installation information.
Key Benefits
- Supports process monitoring across upstream, midstream and refinery duties.
- Matches sensing technology and wetted materials to the measurement point.
- Integrates temperature measurement with the site's classified-area design.
- Reduces thermowell risk through appropriate mechanical review.
Specifications
| Parameter | Typical Specification |
|---|---|
| Standard Process Range | -50°C to 400°C (Pt100 RTD) |
| Refinery / Reactor Range | 400°C to 1200°C (Type K or N Thermocouple) |
| Thermowell Construction | Solid-drilled bar stock, Flanged or RTJ connections |
| Sour Service Review | Wetted materials assessed against process conditions and applicable ISO 15156 requirements |
| Electrical Safety | Protection concept and approved components selected from the site's area classification |
Frequently Asked Questions
Does the temperature sensor come with a hazardous area certification?
Approval cannot be inferred from the sensor description alone. The required protection concept and equipment markings must be specified, and every component in the installed loop must be verified against the site's area classification.
What is NACE compliance?
ISO 15156, historically associated with NACE MR0175, addresses material selection for equipment used in hydrogen-sulfide-containing oil and gas environments. Applicability depends on the material, environment, stress and project specification.
Why use an RTD for custody transfer?
Metering systems often use RTDs because they provide stable, repeatable measurement over moderate temperature ranges. The complete metering design, calibration and applicable standard determine whether a sensor is suitable for custody-transfer service.
How do you measure temperature in a highly viscous fluid?
Viscous fluids require a robust thermowell to withstand the drag force. Furthermore, a longer immersion length or a stepped thermowell design is often used to ensure the sensor reaches past the slow-moving boundary layer to measure the core fluid.
References
Need an engineered solution?
Contact the team to discuss the measurement point, process conditions, installation and instrument requirements.
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