1、Correction Gauge Tables For IncrustationAPI RECOMMENDED PRACTICE 2556SECOND EDITION, AUGUST 1993REAFFIRMED, NOVEMBER 2013Correction Gauge Tables For IncrustationMeasurement CoordinationAPI RECOMMENDED PRACTICE 2556SECOND EDITION, AUGUST 1993REAFFIRMED, NOVEMBER 2013SPECIAL NOTES1. API PUBLICATIONS N
2、ECESSARILY ADDRESS PROBLEMS OF A GENERALNATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE,AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED.2. API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANU-FACTURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIPTHEIR EMPLOYEES, AND
3、OTHERS EXPOSED, CONCERNING HEALTH ANDSAFETY RISKS AND PRECAUTIONS, NOR UNDERTAKING THEIR OBLIGATIONSUNDER LOCAL, STATE, OR FEDERAL LAWS.3. INFORMATION CONCERNING SAFETY AND HEALTH RISKS AND PROPERPRECAUTIONS WITH RESPECT TO PARTICULAR MATERIALS AND CONDI-TIONS SHOULD BE OBTAINED FROM THE EMPLOYER, T
4、HE MANUFACTUREROR SUPPLIER OF THAT MATERIAL, OR THE MATERIAL SAFETY DATA SHEET.4. NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED ASGRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, FOR THE MANU-FACTURE, SALE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COV-ERED BY LETTERS PATENT. NEITHER
5、 SHOULD ANYTHING CONTAINED INTHE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL-ITY FOR INFRINGEMENT OF LETTERS PATENT.5. GENERALLY, API STANDARDS ARE REVIEWED AND REVISED, REAF-FIRMED, OR WITHDRAWN AT LEAST EVERY FIVE YEARS. SOMETIMES A ONE-TIME EXTENSION OF UP TO TWO YEARS WILL BE ADDE
6、D TO THIS REVIEWCYCLE. THIS PUBLICATION WILL NO LONGER BE IN EFFECT FIVE YEARS AF-TER ITS PUBLICATION DATE AS AN OPERATIVE API STANDARD OR, WHEREAN EXTENSION HAS BEEN GRANTED, UPON REPUBLICATION. STATUS OF THEPUBLICATION CAN BE ASCERTAINED FROM THE API AUTHORING DEPART-MENT TELEPHONE (202) 682-8000.
7、 A CATALOG OF API PUBLICATIONS ANDMATERIALS IS PUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API,1220 L STREET, N.W., WASHINGTON, D.C. 20005.Copyright 1993 American Petroleum InstituteiiiFOREWORDIncrustation is defined as any material that adheres to the internal vertical sidewall sur-faces of a tank
8、when the tank is otherwise empty. The purpose of this recommended prac-tice is to give some procedures for measuring and correcting volumetric errors caused byincrustration in tanks.API publications may be used by anyone desiring to do so. Every effort has been madeby the Institute to assure the acc
9、uracy and reliability of the data contained in them; however,the Institute makes no representation, warranty, or guarantee in connection with this pub-lication and hereby expressly disclaims any liability or responsibility for loss or damage re-sulting from its use or for the violation of any federa
10、l, state, or municipal regulation withwhich this publication may conflict.Suggested revisions are invited and should be submitted to Measurement Coordination,Industry Services Department, American Petroleum Institute, 1220 L Street, N.W., Wash-ington, D.C. 20005.vCONTENTSPageSECTION 1GENERAL1.1 Scop
11、e . 11.2 Referenced Publications 1SECTION 2TYPICAL CONDITIONS2.1 Paraffin or Asphalt 12.2 Corrosion . 12.3 Temperature . 1SECTION 3TYPICAL REMEDIES3.1 Lease Automatic Custody Transfer (LACT) . 23.2 Meters 23.3 Heat . 23.4 Cleaning 23.5 Linear Measurement . 2SECTION 4TABLES4.1 Gauge Table Notation .
12、24.2 Tables for Uniform Incrustation 3Tables1Approximate Reduction of Tank Capacity by Uniform IncrustrationIn Barrels per Foot and Percent Capacity . 32Approximate Reduction of Tank Capacity by Uniform IncrustationIn Cubic Meters per Meter and Percent Capacity . 31.1 ScopeIncrustation is defined, f
13、or the purpose of this recom-mended practice, as any material that adheres to the internalvertical sidewall surfaces of a tank when the tank is other-wise empty.Incrustation has the same effect on tank capacity as dead-wood (anything that displaces liquid inside a tank) andshould be treated as such
14、as long as it remains in the tank.The problem of deducting the volume of liquid displaced byincrustation is complicated by two of incrustations basic andtypical characteristics: First, incrustation is difficult to mea-sure, and second, its thickness is usually variable.Some oils present no incrustat
15、ion problem, but manyothers do, usually on a field-wide basis. The error in mea-surement from any one tank may be slight, but the accumu-lated error from an entire field or from any one tank over aperiod of time could be substantial. The error always hasthe effect of indicating too large a tank capa
16、city; therefore,a receiving carrier cannot be expected to continually absorbthe effect of these errors. The method selected to correctthe error should depend upon the desired approach to accu-racy of measurement. The tables given in this recommended practice (see Section4) show the percent of error
17、of measurement caused by vary-ing thicknesses of uniform incrustation in tanks of varioussizes. These tables may be used as a guide by the tank ownerand the carrier to negotiate an allowance for incrustation. If itis established that incrustation is causing a substantial loss toa carrier or to any o
18、ther receiver using affected tank gauges asthe basis for custody transfer measurement, it is the responsi-bility of the tank owner to provide a tank that will permit anaccurate measurement or to agree to a reasonable adjustment.1.2 Referenced PublicationsThe following standard is cited in this recom
19、mendedpractice:APIManual of Petroleum Measurement StandardsChapter 4, “Proving Systems”1Correcting Gauge Tables For IncrustationSECTION 1GENERALcorrosion products and the heavy ends of crude oil. Porousincrustation fills and drains with each filling and emptying ofa tank; therefore, even the most ac
20、curate linear measurementcannot result in accurate deadwood deductions. 2.3 TemperatureSome incrustations are a direct result of the tank shell tem-perature being lower than the pour point of the oil. Theamount of adhesion increases as the temperature of the tankshell decreases.2.1 Paraffin or Aspha
21、ltFor paraffin or asphalt, successive layers of incrustationcontinue to attach to the internal wall surfaces of a tank untilsome areas become overburdened and slough off or until atemperature change causes a cleaning of all surfaces or por-tions thereof.2.2 CorrosionSome adhesions are porous whereas
22、 others are impervi-ous. Porous incrustations usually are a combination of metalSECTION 2TYPICAL CONDITIONSSome of the procedures that are satisfactory in correctingfor the effects of incrustation are given below; however, thisrecommended practice is not intended to preclude other pro-cedures. No si
23、ngle procedure can be recommended for allcases.3.1 Lease Automatic Custody Transfer(LACT)A properly designed, installed, and operated lease auto-matic custody transfer (LACT) unit or truck loading meter-SECTION 3TYPICAL REMEDIES2 API RECOMMENDED PRACTICE 2556ing system will normally solve the proble
24、m caused by in-crustation; however, compromise is in order if the cost of themost accurate procedure cannot be justified by the loss in-curred by the carrier or others concerned.3.2 MetersThe amount of incrustation may be measured by compar-ing the quantities as determined by an accurately calibrate
25、dand properly installed meter against a conventional run ticketcovering the same movement; however, special care shouldbe taken when tanks are calibrated by meter. Meters that areused for measurement should be proven according to Chapter4 of the API Manual of Petroleum Measurement Standards.3.3 Heat
26、If the incrustation is caused by a product that contains waxor gum, the most practical and accurate solution is to ensurethat the liquid and the shell temperatures remain at a levelabove the pour point of such product throughout the deliverycycle. Insulating the tank or the application of heat may b
27、eaccomplished by any safe and practical means, such as steamcoils or heating systems, but direct fire is specifically notrecommended.3.4 CleaningThe tank owner may choose to keep tanks sufficientlyclean to satisfy the carrier or other affected parties. This maybe accomplished in any practical way, s
28、uch as by manual,steam or solvent cleaning; or by the application of a suitablecoating to the interior surfaces of the tanks.3.5 Linear MeasurementWhere the buildup of incrustation is slow and tank runsare infrequent, the most practical solution to correct for in-crustation is probably the use of li
29、near measurements. Thistype of correction is not recommended for tanks with nomi-nal capacities in excess of 65 barrels per foot (35 cubic me-ters per meter). If the incrustation is a type that is imperviousand remains fairly constant, then the amount of deadwoodfor full tank runs can be determined
30、by measuring the thick-ness of the incrustation at a sufficient number of pointswithin the tank to determine an average. An average deduc-tion should be calculated from no less than three measure-ments taken over the span of the tank height beingtransferred. If the incrustation does not remain fairl
31、y con-stant for any reason, such as changes resulting from seasonalthermal effects, it may be necessary to repeat these linearmeasurements to determine if the deduction is still within areasonable tolerance. If less than full tank runs are to be en-countered normally, the incrustation should be simi
32、larly de-termined by linear measurements over the span of the tanksoperating height; however, properly measured varying thick-ness dimensions should be assigned at successive levels up-ward on the vertical walls of the tank. The actual deduction to correct for incrustation should becalculated using
33、Equations 1 and 2 or Equations 3 and 4.For tanks calibrated in customary units,(1)(2)Where:B = tank capacity (barrels per foot).D = tank diameter (feet).I = average incrustation thickness (inches).D B = change in tank capacity due to incrustation (barrelsper foot).For tanks calibrated in SI units,(3
34、)(4)Where:B = tank capacity (cubic meters per meter).D = tank diameter (meters).I = average incrustation thickness (millimeters).D B = change in tank capacity due to incrustation (cubicmeters per meter).BBIDID=4100011000DB= 1 1284.BBIDID=3112DB= 2 6737.4.1 Gauge Table NotationAny tank gauge table th
35、at has been adjusted to correct fordeadwood deductions caused by incrustation should have onits face a note stating the amount of the adjustment and howthe amount was determined. For example: “From the true ca-pacity of this tank, 7.31 barrels have been deducted between1 foot 0 inches and 16 feet 1
36、inch (1.16 cubic meters havebeen deducted between 0.30 meters and 4.90 meters) as a re-sult of errors caused by incrustation. The amount was deter-SECTION 4TABLESCORRECTING GAUGE TABLES FOR INCRUSTATION 3mined by meter according to recommended procedures de-scribed in API MPMS Chapter 4.”4.2 Tables
37、for Uniform IncrustationTables 1 and 2 are intended only to be used as a guide inindicating the approximate effect of uniform incrustation ontanks of various sizes. They are not intended for direct useas a basis for actual deductions to correct for incrustation.Actual deductions should be determined
38、 individually by us-ing one of the typical remedies suggested in Section 3.Table 1Approximate Reduction of Tank Capacityaby Uniform Incrustation in Barrels per Foot and Percent CapacityThickness of Uniform Incrustation(in inches)Tank Size16413211618143812 Bbl/ftBbl/ft 0.007 0.014 0.028 0.056 0.112 0
39、.168 0.224 13% by volume 0.054 0.108 0.216 0.432 0.863 1.292 1.721 Bbl/ft 0.007 0.015 0.029 0.058 0.116 0.174 0.232 14% by volume 0.052 0.104 0.208 0.416 0.831 1.246 1.659 Bbl/ft 0.009 0.017 0.035 0.070 0.139 0.209 0.278 20% by volume 0.044 0.087 0.174 0.348 0.696 1.043 1.389 Bbl/ft 0.011 0.022 0.04
40、5 0.089 0.179 0.268 0.357 33% by volume 0.034 0.068 0.136 0.271 0.542 0.812 1.082 Bbl/ft 0.016 0.031 0.063 0.126 0.251 0.376 0.502 65% by volume 0.024 0.048 0.097 0.193 0.386 0.579 0.772 Note: Refer to the specific tank gauge table capacity to determine tank size that should be used for a specificca
41、se.aUpright cylindrical flat-bottom tank.Table 2Approximate Reduction of Tank Capacityaby Uniform Incrustationin Cubic Meters per Meter and Percent CapacityThickness of Uniform Incrustation(in millimeters)Tank Size0.5 1 2 4 6 8 10 m3/mm3/m 0.005 0.009 0.019 0.037 0.056 0.075 0.093 7% by volume 0.067
42、 0.134 0.268 0.535 0.802 1.069 1.335m3/m 0.005 0.010 0.020 0.040 0.060 0.080 0.100 8% by volume 0.063 0.125 0.251 0.501 0.751 1.000 1.249m3/m 0.006 0.012 0.024 0.047 0.070 0.094 0.117 11% by volume 0.053 0.107 0.214 0.427 0.640 0.853 1.066m3/m 0.008 0.015 0.030 0.060 0.090 0.120 0.150 18% by volume
43、0.042 0.084 0.167 0.334 0.501 0.667 0.834m3/m 0.010 0.021 0.042 0.084 0.126 0.168 0.209 35% by volume 0.030 0.060 0.120 0.240 0.359 0.479 0.598Note: Refer to the specific tank gauge table capacity to determine tank size that should be used for a specificcase.aUpright cylindrical flat-bottom tank.Add
44、itional copies are available through IHSPhone Orders: 1-800-854-7179 (Toll-free in the U.S. and Canada)303-397-7956 (Local and International)Fax Orders: 303-397-2740Online Orders: Information about API Publications, Programs and Servicesis available on the web at www.api.org1220 L Street, NWWashington, DC 20005-4070USA202.682.8000Product No. 852-25560
