9 replies to this topic

[WaqasChemist]

Hi,

 

I am a new comer and my interest is on ASTM D 86 I have done over 300 D 86 test in my petroleum OMC.

 

I want to ask following questions.

 

1: What is the use of ASTM D 86?

2: What quality does ASTM D 86 check?

3: What is the significance of ASTM D 86?

4: How can we detect adulteration in fuel with ASTM D 86?

5: Is only following values of specification of OMCs is enough?

 

Kindly fill in your humble replies.

 

Regards,

 

Waqas Hussain.

 

Chemist, ZPPL.

[PingPong]

ASTM D86 gives vaporization % versus temperature for petroleum products.

 

Gasoline and Diesel have certain requirements for minimum and/or maximum vaporization at certain temperatures.

 

It is also important to define the feed to certain process units such as Catalytic Reformer , FCC unit , Hydrocracker , ......

 

In combination with specific gravity it can moreover be used to estimate other properties of the petroleum product.

[WaqasChemist]

Hi,

 

Thanks for the reply,

 

Can you explain more following:

 

 It is also important to define the feed to certain process units such as Catalytic Reformer , FCC unit , Hydrocracker , ......

Also how to check adulteration in petrol.

 

Take example of following data:

 

IBP  :  40 C

10%:  46 C

20%:  58 C

30%:  66 C

40 %: 76 C

50%:  86 C

60 %: 106 C

70 %: 114 C

80 %: 128 C

85 %: 136 C

90 % 144 C

FBP: 178 C

Residue 1ml.

Recovery: 98 ml:

T Recovery: 99 ml.

[AlertO]

Hi

the data from ASTM D86 shows how much the oil in each section cut contain in the crude from light to heavy. we can use this data to predict how much flow rate will be fed to the downstream unit e.g. Catalytic Reformer , FCC unit , Hydrocracker as mentioned above.

Hope this may make you more clear.

[WaqasChemist]

HI,

 

Thanks for the reply I am not in a refinery but the the above is knowledgeable, keeping the above data in mind:

 

1: How can it tell about the quality of Petrol for a vehicle?

2: How is adulteration determined through this test?

 

Plz elaborate e more. 

[PingPong]

1: How can it tell about the quality of Petrol for a vehicle?

Gasoline and diesel have to obey the specifications set by authorities. In European Union the gasoline spec is defined in EN228, for diesel EN590 applies. These vaporization (D86) requirements in these specs are to assure proper operation of the engines, as well as minimise environmental impact (limit hydrocarbon vapours from tanks, limit soot formation in combustion engines by setting a max value on T95%). One could say: If a fuel meets all specs it has quality; if it does not meet all specs, it cannot be sold (at least not in the EU or the USA) and has to be adjusted by blending with higher quality stocks.

 

2: How is adulteration determined through this test?

I don't understand what you mean.

[JMW]

The trouble with detecting adulteration is that the specification allows for a range of properties, min to max.

This means that some fuels when loaded may be of such a quality that profitable substitutiomn frauds can take place and still leave the resultant adulterated fuel within specification.

However, when a fuel is loaded in the terminal the exact quality of that batch of fuel should be known. By monitoring the density and viscosity (or any other suitable easily and accurately read properties to act as a fingerprint) adulteration can be detected. This is because any significant adulteration will affect one or both values and while it may be feasible to duplicate a single test property, it is not easy to adulterate a fuel and for the resultant fuel to match two or more properties.

I suggest density and viscosity because viscosity is very senstive to change in quality and both density and viscosity can be measured with a single sensor e.g. the LEMIS or Emerson inline or in tank sensors.

[WaqasChemist]

HI

 

Thanks for the reply:

 

Plz consider following Data:

 

A supply Vehicle carrying 40000 Ltrs with V 85 @ 40293 Lts reached at station.

The dips of each chamber at gantry were as follows:

 ch1      ch2      ch3     ch4

1569   1540   1538     1550

receiving dips were:

1566    1534   1534     1540

 

Where as dispatching specific gravity was 0.7410 while receiving average specific gravity of each chamber was 0.7425

 

The temperature at which the lorry was dispatched was 22.5 C which is 72.5 F where (C is Centigrade and F is Fahrenheit)

and receiving Temperature was 19.625 C which is 67.325

 

The Liter / Degree of whole supply vehicle was 23.34 per degree fall and rise from the following formula

 

Liter / Degree= V @ 85 - ambient V / 85 -  (dispatching Temperature in F) + 0.05

this goes as:

 

40293 - 40000/ 85 - 72.5 +0.05 = 23.34

 

Now I multiply the above value with the difference of temperature from dispatching and receiving temperature in Fahrenheit : 

 

Here I checked the samples of each chamber and all were in specification limits.

 

I know the gravity is temperature dependent factor. The limit of Specific gravity for petrol with RON 87 is TBR which was 0.760 previously.

 

I want to know how can Specific gravity here tell us whether there was any adulteration in fuel?

[PingPong]

If a solvent with a different specific gravity than the gasoline has been added, then one should in theory be able to detect its effect. Same applies to viscosity. But both gravity and viscosity are dependent on temperature so you would need to measure all samples at exactly the same temperature, or use proper correction factors to account for temperature differences. It seems to me that in this way it is difficult to prove beyond reasonable doubt that someone tampered with the gasoline.

 

You need to use a gas chromatograph to absolutely prove or disprove adulteration. That will give you a gasoline fingerprint that is unique.

[JMW]

The effect of adulteration will most usually be evident in the corrupted density and/or viscosity from the original values.

But simply checking to see if either or both are within specification is not enough to reveal if the fuel was adulterated or not. Fuel fraud is becoming increasingly sophisticated as more measures are taken. Measuring the density and viscosity is relatively easy using off line equipment such as supplied by Kittiwake. Hence fraudulent suppliers will now take care to ensure that the adulterated fuel remains within specification and thus target fuels that are most vulnerable i.e. where the original density and viscosity are favourable to a significant adulteration and still remain in specification.

 

Specific gravity alone is not enough because if it becomes known that this is the sole test then frauds will be based on ensuring that the specific gravity remains within specification.

Neither is viscosity alone a safe test for the same reason.

However, the reason I mention the INtegrity method is because you are not looking for out of specification fuel but you are looking for a fuel whose specification has changed from when it was loaded at the terminal to when it is received.

Any discrepancy in either density or viscosity will alert you to make further investigations and suspect the fuel quality has in some way been compromised. You may then take samples and have them analysed by a laboratory - and usually any disputes are resoled only with reference to laboratory analysis.

The online sensor acts as a burglar alarm.

I have suggested the combined density and viscosity sensor options as being competitively priced, low/no maintenance/calibration and low skills.

However, as Ping Pong suggests there are other approaches.

Note the inline or in tank density and viscosity sensors will determine the density and kinematic viscosity at the reference temperatures for comparison with the values reported in the original analysis.