Method and apparatus for mixing additives into a fuel

Abstract

Embodiments of the present invention relate to a method and apparatus for mixing additives into a fluid fuel at a predictable concentration. The method comprises: taking a sample of the fuel; mixing the additive into the sample in metered proportions; testing the sample to determine that the correct amount of additive is present; storing the remaining fuel until it is time for the fuel to be used; and mixing the additive into the remainder of the fuel in the same metered proportions.

1 . A method for providing a fuel meeting a predetermined specification of properties, the method comprising:
 taking a sample of the fuel;   mixing an additive into the sample in metered proportions;   testing the sample to determine that the combination of the fuel and the additive meets the predetermined specification of properties;   storing the remaining fuel without the additive for subsequent mixing with the additive into the remainder of the fuel in the same metered proportion.   
     
     
         2 . The method as claimed in  claim 1 , further comprising the step of:
 adjusting the metered proportions of the fuel and the additive where testing reveals that the sample contains an incorrect amount of additive.   
     
     
         3 . The method as claimed in  claim 1 , wherein the fuel and the additive are fluids at the time of mixing. 
     
     
         4 . The method as claimed in  claim 3 , wherein at least one of the fuel and the additive are liquid at the time of mixing. 
     
     
         5 . The method as claimed in  claim 1 , wherein at least one of the fuel and the additive is a hydrocarbon. 
     
     
         6 . The method as claimed in  claim 5 , wherein the hydrocarbon has been distilled from crude oil. 
     
     
         7 . The method as claimed in  claim 5 , wherein one of the fuel and the additive comprises gasoline. 
     
     
         8 . The method as claimed in  claims 5 , wherein one of the fuel and the additive comprises alcohol. 
     
     
         9 . The method as claimed in  claim 8 , wherein the alcohol comprises ethanol. 
     
     
         10 . The method as claimed in  claim 1 , wherein one of the fuel and the additive comprises a bio-fuel. 
     
     
         11 . An apparatus adapted for carrying out the method of  claim 1 , the apparatus comprising;
 a blending system for incorporating the additive into the fuel; and a sample line for taking off a sample of the mixed additive and fuel for testing.   
     
     
         12 . The apparatus as claimed in  claim 11 , wherein the blending system comprises a skid. 
     
     
         13 . The apparatus as claimed in  claim 11 , wherein the blending system comprises a plurality of cylinders, and wherein each cylinder contains a piston, and each cylinder comprises at least one inlet, through which fuel or additive is supplied to the cylinder. 
     
     
         14 . The apparatus as claimed in  claim 13 , wherein each cylinder comprises a first inlet and a second inlet, one at each end of the cylinder, and a valve which in use alternately directs the fuel or additive to the first inlet or the second inlet. 
     
     
         15 . The apparatus as claimed in  claim 14 , wherein, in use, the piston of each cylinder is driven solely by the pressure of fluid entering the cylinder. 
     
     
         16 . The apparatus as claimed in  claim 13 , wherein the blending system comprises a primary cylinder and at least one secondary cylinder, wherein the pistons in the secondary cylinders are arranged to operate in synchrony with the piston in the primary cylinder. 
     
     
         17 . The apparatus as claimed in  claim 16 , wherein each cylinder comprises a first inlet and a second inlet, one at each end of the cylinder, and a valve which in use alternately directs the fuel or additive to the first inlet or the second inlet, wherein the primary cylinder comprises at least one proximity switch, arranged to operate the valve in the primary cylinder when the piston approaches the end of the primary cylinder. 
     
     
         18 . The apparatus as claimed in  claim 17 , wherein the proximity switch in the primary cylinder is also arranged to operate the valves in the secondary cylinders. 
     
     
         19 . The apparatus as claimed in  claim 11 , wherein the apparatus comprises a heat exchanger, and the fuel and the additive are put through opposite sides of the heat exchanger prior to mixing. 
     
     
         20 . The apparatus as claimed in  claim 11 , wherein the cylinders are mounted inside a temperature controlled enclosure.