- Patel's Density Conversion for LPG from observed temperature to 15 C without use of ASTM Table (1980 series) Density unit Kg/L

- Patel's Density Conversion for Liquefied Petroleum Gas (LPG)  from observed temperature to 15 C without use of  ASTM Table.  (Density unit Kg/L).  

A separate post for the density unit Kg/M3 is given here. 

An exact conversion in Android /iOS App is given at the end of this article.

Following simple method help in easily converting LPG density to 15 deg C, without using ASTM Tables, and without help of calculators. It is very handy for field persons who are taking density for comparing parent density for Quality Control purpose. 

LPG is transported in pipeline or marine tankers in cryogenic conditions and usually sample temperature is around 02 -15 deg C.

Secondly, as per request from one of the users, LPG density units used here is Kg/L.   ( 1000 Kg/L = 1 Kg/m3). 

Two different alternate simplified ways are prescribed here. User may find their own alternative.

Option 1.    For LPG.  (Density range 0.5Xx  to 0.59.  Sample Temperature range ----------. )

Simplified   Formula 

                        D₁₅ = d_o - 0.001 x ( 15  – t_o)
       

  Density at 15 deg C= 

  Density observed  -  0.001  x ( 15  –  temp observed  )

 B)  How to use formula manually without calculator

     

 Example : 1  LPG

       Density observed = 0.568  kg/L

       Temp. observed   =  9 deg c

        ASTM table 53 B  = 0.5618 kg/L

      

Steps :   1)   find difference  (15 - 9) manually ie.  6

              2)   multiply difference and 0.001  ie.  6 x 0.001 = 0.006       

              3)  Subtract  this product from observed density ie.  
                                0.568 - 0.006 = 0.562    = 0.5620 kg/L

Example : 2.  LPG

                   Density observed = 0.5853 kg/L

                  Temp. observed   =  11.8  deg c

                   ASTM table 53 B  = 0.5820 kg/L

 Steps :   1)   find difference  (15 - 11.8) manually ie.  3.2

              2)   multiply difference and 0.001  ie. 3.2 x 0.001 = 0.0032       

              3)  Subtract  this product from observed density ie.  
                                0.5853 - 0.0032 = 0.5821   = 0.5821 kg/L

Option 2.  For Propane,  Butane and LPG.  (Density range 0.5xx  to 0.60  Kg/L,  Temperature range  -2  to 12 C)

Simplified   Formula 

                        D₁₅ = d_o  - 0.01 + 0.001 x (   t_o – T)
       

  Density at 15 deg C= 
  Density observed  - 0.01 + 0.001  x ( temp observed – T )

Where  value of T is :

Petroleum Product	T
Propane	6.0
Butane /LPG	5.5

   

Apps developed on Petroleum Calculations - see here.

B)  How to use formula manually without calculator

     

 Example : 1  LPG

       Density observed = 0.568  kg/L

       Temp. observed   =  9 deg c

        ASTM table 53 B  = 0.5618 kg/L

      

Steps :   1)  subtract 0.01 to observed density    ie.  0.558 kg/L

               2)  find difference  (   t_o – 5.5) manually ie.  3.5

              3)   multiply difference and 0.001  ie.  3.5 x 0.001 = 0.0035       

              4) Add this product to step 1 ie.  0.558  + 0.0035 = 0.5615 kg/L

Example : 2.  LPG

                   Density observed = 0.5853 kg/L

                  Temp. observed   =  11.8  deg c

                   ASTM table 53 B  = 0.5820 kg/L

 Steps :   1)  subtract 0.01 to observed density    ie.  0.5753 kg/L

               2)  find difference  (   t_o – 5.5) manually ie.  6.3

              3)   multiply difference and 0.001  ie.  6.3 x 0.001 = 0.0063       

              4) Add this product to step 1 ie.  0.5753  + 0.0063 = 0.5816 kg/L

The above is for ASTM Density Conversion tables of 1980 series.  

The equation given above was first developed in 1987 by author and since then extensively used for density conversion for pipeline, tanker and tank truck bullets   samples outside Laboratory/office where it is a bit inconvenient to take out ASTM table Book for density conversion.

The reader may please remember here that author's idea is to convert observed density to 15 deg C density in field with accuracy and simplicity,   however for exact conversion as per ASTM table 53 B can be found in Apps below:

The above Apps convert density from observed temperature to  15 C as well as 20 C.

                                       

Apps developed on Petroleum Calculations - see here.
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