API MPMS 12.1.1:2001(R2008) pdf download
API MPMS 12.1.1:2001(R2008) pdf download.Manual of Petroleum Measurement Standards Chapter 12- Calculation of Petroleum Quantities Section 1- Calculation of Static Petroleum Quantities Part 1- Upright Cylindrical Tanks and Marine Vessels.
For practical operational purposes the recommended methorts of taking this temperature are:
I. A temperature deviix earned by the gauger into the Lank area when gauging tanks. Takc at lca.st one tcmpera Lure reading in a shadcd area. If more than one temperature is taken, average the readings.
2. Shaded external thermometers permanently mounted in the tank farm area.
3. Lxal tm-site weather stations.
All on ole temperature devices, used to recant ambient air temperature for thc calculation of tank shell correction factors during custody transfer shall have their accuracy of plus or mmu. two degrees Fahrenheit verified exeiy three mtmth.
Where the uncertainty of the ambient air temperature is plus or minus live degrees Fahrenheit. the effect on calcubting the tank shell correction factor is I in 100.000.
Temperature readings arc to be taken 3 ft (I meter I from any obstwct*nns or the ground. Additionally. allow sufficient time for temperature readings to stahili,e.
9.1.3.2 For insulated metal tanks, the temperature of the shell may he taken as closely approximating the adjacent liquid temperature, in which case. 7Sh 71.
9.1.3.3 In applying thesc principles so uptight cylindrical tanks, the horiiont-al cross-sectional area may be taken as a function of tank calibration. ‘The cuduicicnt determined front Equation I (see 913) is predicated tat a thermal expansion for low-cwt’ion Mccl per degree Fahrenheit.
Note: Thc cross-sectional correction Equation I) sill hase to be modified (or gainless steel tanks bascd upon thc cncflkicnt of expiasion (or the type of stainless steel.
91.3.4 The third dimension needed to generate volume— height—is a function of gauging and shouki be considered separately. ‘The volumes reflected on tank tabics are derived from area times incremental height Therefore. K- factors lot correction of areas have the same ratio as volume corrections and may be applied directly to tank table volumes. Fur an example calculation see Appendix H.
9.1.3.5 The shell temperature correction factor is to he applied to volumes obtained horn capacity tables that are at
*dYF and arc unrelated to the corre.iions designed to acconnt foe voluitte expuitsion and co trat-tioti of the product itself. Depending upon certain requirements. this shell temperature correction factor may he built into the capacity table for a specific operating temperature.
9.1,4 Floating Roof Adjustment (FRA)
The correction for the displacement of the floating root can be addressed in one of tsvo ways:
9.2.1 Total Observed Volume (TOP)
Thc 70V is obtained from the vcsscl’s capacity t.tbJc%. which are entered with one ol the following:
a. The observed ulbge or innage, if the trim andor list cornxtions are a soluinestic adjustinen l’he amount of trim andor list cun-ection vwill need to be applied to the RWquantily to arrive at a torn anttor list corrected iVY
The trim and or list corrected ullage or innage.
c. The observed ullagc or innage and the ujel’s trim. Some eapucity tables show varying TOV values for the same gauge under differing conditions of torn.
9.2.2 Trim Correction
The trim correction is applied to compensate for the change in liquid level due to the longitudinal plane of the s’cseel not being horizontal.
Subtract the Iaisard draft reading from the after draft reading. If the trim is positive (that is. the after draft reading is largcfl. the vessel is said to he rirnmed b& the stcni’ If the trim is negative Ithat is. the lorward draft reading is larger). the vessel is said to be rimmcd by the head.” Note the lol lowing:
a. The trim correction is fosmd in the vessel’s calibration tables and is uuaI1y a correction to the observed innage ullage: however. it can be i volumetric adjustment to the ITA’ ii. Trim corrections can be either positive or negative. The trim correction table will state how this correction is to be applied.
c. II trim corrections arc not available, it may be possible to calculate this value. Refer to the equation and Figure I.
