ASTM D1018 standard test method for hydrogen in petroleum fractions
5. Apparatus
5.1 Lamp - A lamp (see Note 1) consisting of a 25-mL Erlenmeyer flask, a burner, and a burner cap conforming to the dimensions shown in Fig. 1. The burner consists of two concentric glass tubes, the external one having an arm, provided with standard-taper glass joints for connection with the flask, chimney, and burner cap. The burner has a small opening near its base to allow equalization of the pressure between the chimney and flask.
NOTE 1 - The lamp and burner are constructed in accordance with Appendix A3 of Test Method D1266.
5.2 Chimney - A chimney (see Note 2) conforming to the dimensions shown in Fig. 1.
NOTE 2 - The chimney is constructed in accordance with Appendix A3 of Test Method D1266, except that the delivery tube is cut off and a short length of glass tubing is sealed on at right angles to the chimney. The secondary air inlet is not used and is sealed off.
5.3 Absorbers - Two absorption bulbs suitable for collecting and weighing the water formed during combustion of the sample. The bulbs shall be filled in the following manner: a 1 to 2-cm layer of glass wool, a 5-cm layer of 6 to 10-mesh cp anhydrous calcium chloride, a 1-cm layer of glass wool, a 2-cm layer of phosphorus pentoxide, and glass wool to the top of the absorbers. One filling is sufficient for approximately 10 g of water.
5.4 Cotton Wicking - Clean, unused, uniform, two-strand twisted cotton wicking of good quality, weighing 0.5 to 0.6 g/m per strand.
5.5 Air Purifying System - The compressed air (Warning - Compressed gas under higher pressure) for the combustion shall be purified by passage through a scrubber containing sulfuric acid (relative density 1.84), a surge chamber packed with glass wool, and a drying tower filled with 10 to 20-mesh anhydrous calcium sulfate and phosphorus pentoxide in that order. A length of rubber tubing suitable for connection to the inlet tube of the burner shall be connected to the exit of the tower.
5.6 Drying Tube - A small U-tube containing anhydrous calcium sulfate.
5.7 Ice-Water Bath, large enough to hold the two absorbers in tandem, immersed to a depth of approximately 5 cm.
6. Reagents and Materials
6.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
6.2 Calcium chloride (CaCl2).
6.3 Calcium sulfate, anhydrous (CaSO4).
6.4 Phosphorous pentoxide (P2O5).
6.5 Sulfuric acid (H2SO4), relative density 1.84.
6.6 Quality Control (QC) Samples, preferably, portions of one or more liquid petroleum materials that are stable and representative of the samples of interest. These QC samples can be used to check the validity of the testing process, as described in Section 10.
7. Sampling
7.1 Obtain samples in accordance with the instructions in Practices D4057 or D4177. Ensure that test specimens are representative of the test unit. Vigorous stirring or shaking may be necessary.
