API MPMS 7:2001 pdf download
API MPMS 7:2001 pdf download.Manual of Petroleum Measurement Standards.
3.13 total-immersion thermometer: A liquid-in-glass thermometer designed to indicate temperatures correctly when just that portion of the thermometer containing the liquid is exposed in the temperature being measured.
3.14 transient: As used in this standard, refers to high- voltage, fast-rising, lower-energy pulses. The disturbances caused by transients usually have duration of 0.2 seconds.
4 Significance and Use
Temperature has the most significant effect on the accurate determination of liquid quantities when correcting to standard conditions for custody transfer and inventory control purposes. As a result, the most accurate means for temperature determination should be used for these applications.
The average temperature of a liquid is required to calculate its volume at a standard temperature, so it is imperative that temperatures be determined accurately.
For custody transfer, the means of temperature determination should be agreed to among the parties involved.
This standard presents both Metric (SI) and US Customary units, and may be implemented in either system of units. The presentations of both units are for convenience of the user, and are not necessarily exact conversions. The units of implementation are typically determined by contract, regulatory requirement, the manufacturer, or the user’s calibration program. Once a system of units is chosen for a given application, it is not the intent of this standard to allow arbitrarily changing units within this standard.
5 Equipment and Apparatus
Many types of temperature devices are available. The temperature device used must be selected to match application requirements. Considerations should include temperature range, scale (°C or Oj) response time, accuracy, discrimination, repeatability, and ambient temperature and atmospheric conditions where the device is installed. The ultimate use of the temperature data must also be considered.
Accuracy requirements, mechanical limits, operating I im— its, ambient conditions, and individual preferences must he considered when selecting a temperature device to be used for temperature determination on a metered stream or meter prover. In addition, the ability of the device to sense and record the actual temperature of a liquid to the specified temperature increments (temperature discrimination) must be evaluated. API MPMS Chapter 12 provides temperature discrimination requirements for various measurements and calculations.
The use of a temperature device that can perform to a more stringent discrimination than required in Chapter 12 is acceptable and preferred. However, the selection, installation, maintenance, operation, and calibration of such equipment must be adequate to ensure temperature-device performance to the level chosen and agreed to by all parties involved.
The operational range limits, as well as the ambient impact on the measurement accuracy of all equipment as part of a temperature measurement system shall be clearly stated and provided by the equipment manufacturer.
The following equipment and apparatus are used in temperature determination:
5.1 FIXED AUTOMATIC TANK THERMOMETERS (ATrs)
An All’ system may be used for either custody transfer or inventory control purposes. The use of an ATT system for custody transfer normally requires mutual contractual agreement between the buyer and the seller and may he subject to federal, state, or local regulations.
An AT!’ system typically consists of temperature element(s). fixed thermowel 1(s), and telemetry and readout equipment.
Most aboveground bulk storage tanks are equipped with at least one local direct-reading thermometer (described in Appendix B) mounted in a fixed thermowell. This local thermometer is not considered part of the AT!’ system, and it is not recommended for custody transfer temperature determination.
For custody transfer temperature measurement. local direct-reading thermometers are not recommended. Copper or platinum temperature element bulbs, that is, resistance temperature detectors (RTDs), are normally used for this application.
The selection of a single-point (spot), mid-level, multiple- point, or an averaging AT!’ should he made based on the expected tank temperature stratification and the accuracy requirements (custody transfer versus inventory control).
Safety and material compatibility precautions should be taken into consideration when using fixed AT systems. The manufacturer’s recommendations on the use and installation of the equipment should be followed.
