Method for the measurement of the reactive molecular species in liquid petroleum and liquid petroleum products

Abstract

An apparatus and method for the direct measurement of corrosive sulfur and other corrosive compounds is provided. The method and apparatus of the current invention provides a rapid, reliable and cost effective method to directly measure the content of corrosive compounds in various fluids, and in particular liquid petroleum and liquid petroleum products such as gasoline. The apparatus can be retrofit to existing analyzers where they exist, or easily installed in locations that require such analysis.

1 . An apparatus for the on-line measurement of reactive molecular species of a chemical element present within a liquid that can react with a target material comprising:
 an analyzer capable of measuring the total content of the chemical element;   a flow splitting device positioned upstream from the analyzer that splits on-line flow of the liquid into a first stream and a second stream that both flow to the analyzer, wherein the first stream flows untreated to the analyzer; and   a pre-treatment device positioned in the second stream prior to the analyzer, wherein the pre-treatment device selectively removes the reactive molecular species of the element from the liquid that would react with a target material,   whereby a measurement of the total content of the chemical element is taken from each stream.   
   
   
       2 . The apparatus of  claim 1  where the target material comprises a metal. 
   
   
       3 . The apparatus of  claim 1  where the pre-treatment means comprises a sacrificial reactant that removes the reactive molecular species. 
   
   
       4 . The apparatus of  claim 3  wherein the pre-treatment means is a plug flow packed bed reactor comprising the sacrificial reactant. 
   
   
       5 . The apparatus of  claim 3  where the sacrificial reactant comprises a metal. 
   
   
       6 . The apparatus of  claim 3  where the target material comprises a metal, where the sacrificial reactant comprises metal and where the target material and the sacrificial reactant both comprise the same type of metal. 
   
   
       7 . The apparatus of  claim 1  where the reactive molecular species of a chemical element are reactive sulfur species. 
   
   
       8 . The apparatus of  claim 1  where the target material comprises silver, where the sacrificial reactant comprises silver and where the reactive molecular species of a chemical element are silver reactive sulfur species. 
   
   
       9 . The apparatus of  claim 8  where the silver reactive sulfur species comprise elemental sulfur and hydrogen sulfide. 
   
   
       10 . The apparatus of  claim 8  where the pre-treatment means is a plug flow packed bed reactor containing a sacrificial reactant that removes reactive species. 
   
   
       11 . The apparatus of  claim 1  wherein the liquid is selected from liquid petroleum and liquid petroleum products. 
   
   
       12 . The apparatus of  claim 11  wherein the liquid is an automotive fuel. 
   
   
       13 . The apparatus of  claim 12  where the liquid is gasoline. 
   
   
       14 . The apparatus of  claim 1  wherein the analyzer is a monochromatic wavelength-dispersive X-ray fluorescence spectrometer. 
   
   
       15 . The apparatus of  claim 1  where the target material comprises silver, where the sacrificial reactant comprises silver, where the reactive molecular species of a chemical element are silver reactive sulfur species, and where the liquid is an automotive fuel. 
   
   
       16 . The apparatus of  claim 1  comprising a computer program that automatically receives and compares the total content of the chemical element in each stream and calculates a difference that represents the content of reactive compounds in the liquid. 
   
   
       17 . A method for measuring the content of reactive molecular species of a chemical element present in a liquid that can react with a target material comprising the steps of:
 (i) measuring the total content of the chemical element in a non-treated first sample of liquid;   (ii) removing reactive molecular species of the chemical element that can react with the target material from a second sample of the liquid to form a treated sample;   (iii) measuring the total content of the chemical element in the treated sample;   (iv) determining the total content of the reactive molecular species of the chemical element in the liquid by calculating the difference in the total content of the chemical element in the non-treated sample and the treated sample.   (v) optionally repeating steps i) through iv) one or more times.   
   
   
       18 . The method of  claim 17  where the target material comprises a metal. 
   
   
       19 . The method of  claim 18  where the removing step uses a sacrificial reactant that removes the reactive molecular species. 
   
   
       20 . The method of  claim 19  wherein the sacrificial reactant is configured in a plug flow packed bed reactor. 
   
   
       21 . The method of  claim 20  where the sacrificial reactant comprises a metal. 
   
   
       22 . The method of  claim 21  where the sacrificial reactant and the target material both comprise the same metal. 
   
   
       23 . The method of  claim 17  wherein the element is sulfur and the reactive molecular species of the element are reactive sulfur species. 
   
   
       24 . The method of  claim 23  wherein the step for removing the reactive sulfur species is performed by exposing the second sample to a plug flow packed bed reactor containing a sacrificial reactant that removes reactive sulfur species. 
   
   
       25 . The method of  claim 24  where the target material is silver and the sacrificial reactant comprises one or more of the following metals: silver, copper, brass, sodium and alloys thereof. 
   
   
       26 . The method of  claim 25  wherein the sacrificial reactant is silver. 
   
   
       27 . The method of  claim 17  wherein the liquid is selected from liquid petroleum and liquid petroleum products. 
   
   
       28 . The method of  claim 27  wherein the liquid is gasoline. 
   
   
       29 . A method for measuring the content of silver reactive sulfur species present in an automotive fuel comprising the steps of:
 (i) measuring the total content of sulfur in a first non-treated sample of fuel;   (ii) removing silver reactive sulfur species from a second sample of the fuel to form a treated sample;   (iii) measuring the total content of sulfur in the treated sample;   (iv) determining the total content of the sulfur reactive molecular species in the fuel by calculating the difference in the total sulfur content in the non-treated sample and the treated sample.   (v) optionally repeating steps i) through iv) to obtain more than one determination of the total content of the reactive species in the liquid.   
   
   
       30 . The method of  claim 29  wherein the steps for measuring the total content of the sulfur are performed using a monochromatic wavelength-dispersive X-ray fluorescence spectrometer. 
   
   
       31 . The method of  claim 27  wherein an amount of corrosion inhibitor additive is added to the fuel depending on the amount of reactive sulfur species detected.