1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB
2、ED HEREIN CAN BE HAZARDOUS. SAFETY DATA SHEETS (SDS) OR EXPERIMENTAL SAFETY DATA SHEETS (ESDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 2017 UOP LLC. All rights reserved. Ash from Petroleum Prod
3、ucts by Microwave UOP Method 1016-17 Scope This test method covers the determination of ash in the range 0.01 to about 50.0 mass-%, in petroleum products ranging from distillate and residual fuels to crude oils and waxes to pitches and asphalts using a microwave ashing oven. References UOP Method 99
4、9, “Precision Statements in UOP Methods,” www.astm.org Outline of Method The sample is weighed into a crucible (ceramic, platinum, nickel, or quartz) and reduced to ash by heating in a microwave ashing oven at 775C, cooled and weighed. Size and type of crucible is determined by the amount of sample
5、to be weighed. The ramping stages of the heating profile are determined by the type of sample, with liquids requiring a longer ramp time than materials that are solid at room temperature. Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other su
6、ppliers may be used. Pyro XL microwave ashing system, Milestone, Cat. No. 47096, including analytical balance capable of direct communication with the Milestone controller and weighing up to 220g +/- 0.1mg Crucible, quartz, 10ml, Milestone, Cat. No. 40224 Crucible, ceramic, 100ml, Milestone, Cat. No
7、. CRU100 Crucible, ceramic, 50ml, Milestone, Cat. No. CRU50 Crucible, ceramic, 25ml, Milestone, Cat. No. CRU25 Procedure The analyst is expected to be familiar with general laboratory practices, and the equipment being used. Dispose of used reagents, materials, and samples in an environmentally safe
8、 manner in accordance with local regulations. Set Operating Parameters Install the analyzer according to the instructions in the manufacturers operating manual. The conditions listed in Table 1 and Table 2 apply specifically to the Milestone PyroXL microwave 2 of 3 1016-17 ashing system. If other in
9、strumentation is used, the conditions may be different depending on the wattage, exhaust velocity, and chamber dimensions. Table 1 PyroXL Settings for Samples Liquid at Room Temp Step Watts Time Temp C Ramp 1000 00:05:00 90 Hold 1000 00:30:00 90 Ramp 1200 01:00:00 775 Hold 1200 01:00:00 775 Exhaust
10、0 00:45:00 0 Table 2 PyroXL Settings for Samples Solid at Room Temp Step Watts Time Temp C Ramp 1000 00:05:00 90 Hold 1000 00:20:00 90 Ramp 1200 01:00:00 775 Hold 1200 02:00:00 775 Exhaust 0 00:45:00 0 Determine Sample and Crucible Size Sample size and crucible size and type are determined based on
11、the estimated concentration of ash. Liquid samples will require larger crucibles to allow larger sample weights. See Table 3. Table 3 Determining Sample Weight and Crucible Size Sample Type Estimated %Ash Sample Weight Crucible Size Liquid at room temp 0.01 to 5.00 10 to 20 g 50 to 100 ml Liquid at
12、room temp 5.00 5 to 10 g 25 to 50 ml Solid at room temp 0.01 to 5.00 5 to 10 g 25 ml Solid at room temp 5.00 1 to 5 g 10 to 25 ml Sample Analysis Analyze samples and quality control materials as follows: 1. Weigh clean, dry crucible and record weight to 0.0001 g. 2. Add appropriate amount of sample
13、to the crucible and record weight; see Table 3. Sample must be homogenous so stirring with a spatula may be required. Samples that are solid at room temperature or viscous may require heating in order to thoroughly mix, which can be done in an oven of appropriate temperature. 3. Place crucibles with
14、 samples into microwave ashing oven chamber, close oven door and start ashing program. Program the microwave ashing oven according to manufacturer instructions for the sample type. Table 1 and Table 2 list parameters for the Milestone PyroXL microwave ashing system. 4. After program is complete care
15、fully remove the crucibles and reweigh, recording the weight. If crucibles are warm allow to cool to ambient temperature inside the ashing oven, or use appropriate heat resistant gloves or tongs and place crucibles in a desiccator. Reweigh after reaching ambient temperature. 5. Calculate ash concent
16、ration; see Calculations. 6. Clean crucibles and discard ash residue. 3 of 3 1016-17 Calculations Calculate the mass of the ash in the original sample as follows: Ash, mass % = 100 * CS CA where: A = weight of crucible and ash residue, g C = weight of crucible, g S = weight of crucible and sample, g
17、 For values from 0.01 mass-% to 10.0 mass-%, report to two decimal places. For values 10.0 mass-% and higher, report to one decimal place. Precision Precision statements were determined using UOP Method 999, “Precision Statements in UOP Methods,” from precision data obtained using an autosampler. Re
18、peatability and Site Precision A nested design was carried out for determining ash on three different samples by two analysts, with each analyst performing analyses on two separate days, performing two analyses each day for a total of 24 analyses. Using a stepwise analysis of variance procedure, the
19、 within-day estimated standard deviations (esd) were calculated at the concentration means listed in Table 2. Two analyses performed in one laboratory by the same analyst on the same day should not differ by more than the repeatability allowable differences shown in Table 2 with 95% confidence. Two
20、analyses performed in one laboratory by different analysts on different days should not differ by more than the site precision allowable differences shown in Table 2 with 95% confidence. Table 4 Repeatability and Site Precision, mass-% Repeatability Site Precision mean Within Day esd Allowable Diffe
21、rence Within Lab esd Allowable Difference Asphaltenes 41.13 0.395 1.29 0.433 1.41 Pitch 9.25 0.110 0.36 0.133 0.44 Residual Fuel Oil 1.20 0.082 0.27 0.097 0.32 The data in Table 4 are a short-term estimate of repeatability. When the test is run routinely, a control standard and chart should be used
22、to develop a better estimate of the long-term repeatability. Reproducibility There is insufficient data to calculate the reproducibility of the test at this time. Time for Analysis The elapsed time for this method is 4 to 5 hours. Labor time varies based on the need to heat and mix the samples. Suggested Suppliers Milestone Inc., 25 Controls Drive Shelton, CT 06484, USA, 1-866-995-5100,
