API MPMS 10.9 2013 pdf free download
API MPMS 10.9 2013 pdf free download.Manual of Petroleum Measurement Standards Chapter 10.9 Standard Test Method for Water in Crude Oils by Coulometric Karl Fischer Titration.
1. Scope* 1.1 This test method covers the determination of water in the range from 0.02 to 5.00 mass or volume % in crude oils. Mercaptan (RSH) and sulfide (S − or H 2 S) as sulfur are known to interfere with this test method, but at levels of less than 500 µg/g [ppm(m)], the interference from these compounds is insignificant (see Section 6). 1.2 This test method can be used to determine water in the 0.005 to 0.02 mass % range, but the effects of the mercaptan and sulfide interference at these levels has not been deter- mined. For the range 0.005 to 0.02 mass %, there is no precision or bias statement. 1.3 This test method is intended for use with standard commercially available coulometric Karl Fischer reagent. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. For specific warning statements, see Section 8. 2. Referenced Documents 2.1 ASTM Standards: 2 D1193 Specification for Reagent Water D4057 Practice for Manual Sampling of Petroleum and Petroleum Products (API MPMS Chapter 8.1)
8.4 Karl Fischer Reagent—Standard commercially avail- able reagents for coulometric Karl Fischer titrations. 8.4.1 Anode and cathode reagents shall not be used past the manufacturer’s expiration date. 8.4.2 The need to replace the anode and cathode reagent is a function of number of tests run and the amount of water previously titrated. An abnormally slow titration is an indica- tion that the reagents should be replaced. 8.4.3 Anode Reagent—A mixture of commercial coulomet- ric Karl Fischer anode reagent and reagent grade xylene, typically in a 6:4 mixture. Other proportions of anode reagent and xylene can be used and should be determined for a particular reagent and apparatus. The precision and bias were established using a 6 parts Karl Fischer reagent and 4 parts xylene. (Warning—Flammable, toxic by inhalation and if swallowed, avoid contact with skin.) 8.4.4 Cathode Reagent—Use standard commercially avail- able coulometric Karl Fischer cathode reagent. (Warning— Flammable, can be fatal if inhaled, swallowed, or absorbed through skin. Possible cancer hazard.) 8.4.5 Check Solution—NIST Traceable check solution used for verifying the calibration of the Karl Fischer instrument. In the absence of an available check solution, pure water may be used. 9. Sampling and Test Specimens 9.1 Sample Container—It shall be constructed of a material to which water does not adhere with a sealable lid or other mechanism to prevent rain or humidity from contaminating the sample. 9.1.1 If a non-aerating high-speed shear mixer is to be used, the sample container shall be of sufficient dimensions to allow mixing as described in 9.6 and consistent with the sample container used in any mixer efficiency testing.
9.5 Sampling Method—Representative samples obtained as specified in Practice D4057 (API MPMS Chapter 8.1) and Practice D4177 (API MPMS Chapter 8.2) should be used to obtain the sample. 9.5.1 Sampling Viscous Crude Oil—Application of this method of viscous crude oils may present challenges in two different areas; sample mixing and test specimen extraction. Mixing apparatus may operate less efficiently. It may be difficult or impossible to extract and deliver an exact quantity of test specimen (see Section 15). Equipment or procedure modifications if required may invalidate the precision state- ment in this method. Validation of any modifications are required. 9.6 Sample Mixing: 9.6.1 In order for the test specimen to be representative of the sample, the sample must first be homogenized. This is accomplished by mixing the sample using an appropriate mixer for a specified period of time. 9.6.2 The mixer shall meet the specifications for the homog- enization test, Practice D5854 (API MPMS Chapter 8.3). Reevaluate the mixer for any changes in the type of crude, volume of crude in the container, the shape of the container, or the mixing conditions (such as mixing speed and time of mixing). 9.6.2.1 For small sample containers and volumes in the 50 to 500 mL range, a non-aerating, highspeed, shear mixer may be used. Use the parameters found to be satisfactory in the Practice D5854 (API MPMS Chapter 8.3) homogenization test. 9.6.2.2 For larger containers and volumes larger than 500 mL, appropriate mixing conditions shall be defined by follow- ing a set of procedures similar to those outlined in Practice D5854 (API MPMS Chapter 8.3) but modified for application to the larger containers and volumes.
