Category: Petroleum

Procedure of Calculations Using Density, API & Relative Density

Marine Surveyor Information 1602282

 

Working with Density at 15°C in air:
1) Observed Ullage – apply corrections – get Corrected Ullage
2) Observed Interface – apply corrections – get Corrected Interface
3) From Corrected Ullage, find Total Observed Volume TOV (in cubic metres)
4) From Corrected Interface, find Volume of Water (in cubic metres)
5) TOV – Water = Gross Observed Volume (GOV) of Cargo (in cubic metres)
6) Use Density at 15°C and Observed Temperature (°C) and find Volume Correction Factor (VCF) from Table 54
7) Gross Standard Volume (GSV) = GOV x VCF (cubic metres)
8) Weight Correction Factor (WCF) = Density at 15°C in vacuum – 0.0011 (or the Density at 15°C in air)
9) Weight in Air (Metric Ton) = GSV x WCF(Density at 15°C in air)
10) Weight in Vaccum (Metric Ton) = GSV x Density at 15°C in vacuum
Continue reading “Procedure of Calculations Using Density, API & Relative Density”

ASTM Table Series for Oil Survey

Marine Surveyor Information 1601281
Series I – TABLE 5 & 6 – FOR API, °F, 60°F
Volume I – Generalized Crude Oils (Tables 5A & 6A)
Volume II – Generalized Products (Tables 5B and 6B)
Volume III – Individual and Special Applications (Table 6C)

Series II – TABLE 23 & 24 – FOR RELATIVE DENSITY, °F, 60°F
Volume IV – Generalized Crude Oils (Tables 23A & 24A)
Volume V – Generalized Products (Tables 23B and 24B)
Volume VI – Individual and Special Applications (Table 24C)
Continue reading “ASTM Table Series for Oil Survey”

Petroleum Calculation Series: Wedge Formula

marine-surveyor-wedge-formulaAs I have requested by comments to post about Wedge Formula of liquid cargo measurement, herewith the article collected from internet

What is Wedge Formula?
Wedge Formula is calculation to determine the small quantity of liquid or non liquid cargo (On Board Quantity – OBQ or Remaining On Board – ROB) on cargo tanks, where it should fulfill the following conditions :
– The vessel has huge trim, but there is no trim correction value available on the tank table,
– The liquid or cargo on tank is not touch one or more of the tank bulkheads,
– Observed sounding tanks at several points to ensure the cargo is not touch one of the tank bulkheads,

Continue reading “Petroleum Calculation Series: Wedge Formula”

Gas Tanker: Specimen of Calculation

marine cargo ship surveyors

The following example demonstrates the typical procedure outlined using the standard temperature of 15°C as applied to cargo in a ship’s tank.

Measurement data — Tank No.3 port
Product — Propane
Gauge reading of liquid depth  ………………………………….. : 10.020 metres
Ship’s trim ……………………………………………………………. : 2.0 metres by stern
Ship’s list …………………………………………………………………. : 0.5° to port
Mean temperature of liquid ……………………………………….. : – 43°C
Mean temperature of vapour………………………………………. : – 38°C
Vapour space pressure ……………………………………………… : 59 mbarg
Molecular weight of liquid …………………………………………. : 44.097 given by
Density of liquid at 15°C ……………………………..…………….. : 511 kg/m3 shore
Continue reading “Gas Tanker: Specimen of Calculation”

Gas Tanker Calculation Procedures

marine cargo ship surveyors

Independent cargo surveyors are often employed by cargo buyers or sellers and the survey companies provide personnel to check cargo operations and cargo quantities both on board ship and within terminals. Such activities can include cargo measuring and cargo sampling.

During cargo operations, it is important to maintain a log of events. Ship’s officers and shore personnel should ensure that their time records are in agreement and that, when independent cargo surveyors are used, similar times are recorded in the Surveyor’s Time Sheet.

Continue reading “Gas Tanker Calculation Procedures”

Petroleum Calculation Series: Gas Tanker Principal Products

marine cargo ship surveyorsThe hydrocarbon gases methane, ethane, propane and butane may be regarded principally as fuels, the LPGs are also important as feedstock in the production of the chemical gases.

Liquefied Natural Gas (LNG)
Natural gas is transported either by pipeline as a gas or by sea in its liquefied form as LNG. Natural gas comes from underground deposits. Its composition varies according to where it is found but methane is by far the predominant constituent, ranging from 70 per cent to 99 per cent. Natural gas is now a major commodity in the world energy market and approximately 73 million tonnes are carried by sea each year. This is expected to increase to 100 million tonnes per year by the end of the millennium.

Continue reading “Petroleum Calculation Series: Gas Tanker Principal Products”

Petroleum Calculation Series: Gas Tanker Terms

Absolute Pressure
The absolute pressure is the total of the gauge pressure plus the pressure of the surrounding atmosphere.

Absolute Temperature
The fundamental temperature scale with its zero at absolute zero and expressed in degrees Kelvin. One degree Kelvin is equal to one degree Celsius or one degree Centigrade. For the purpose of practical calculations in order to convert Celsius to Kelvin add 273. It is normal for the degree Kelvin to be abbreviated in mathematical formulae to ‘K’ with the degree symbol being omitted.

Absolute Zero
The temperature at which the volume of a gas theoretically becomes zero and all thermal motion ceases. It is generally accepted as being -273.16°C.

Activated Alumina
A desiccant (or drying) medium which operates by adsorption of water molecules.

Continue reading “Petroleum Calculation Series: Gas Tanker Terms”