ASTM D7621-16 (R2021) pdf free download.Standard Test Method for Determination of Hydrogen Sulfide in Fuel Oils by Rapid Liquid Phase Extraction.
At very low concentrations, the gas has the characteristic smell of rotten eggs. However, at higher concentrations, it causes a loss of smell, headaches, and dizziness, and at very high concentrations, it causes instantaneous death. It is strongly recommended that personnel involved in the testing for hydrogen sulfide arc aware of the hazards of vapor-phase H2S and have in place appropriate processes and procedures to manage the risk of exposure.)
5.2 This test method was developed so refiners, fuel terminal operators, and independent testing laboratory personnel can rapidly and precisely measure the amount of H2S in residual fuel oils and distillate blend stocks, with a minimum of training, in a wide range of locations.
5.3 Test Method D5705 provides a simple and consistent field test method for the rapid determination of H,S in the residual fuel oils vapor phase. However it does not necessarily simulate the vapor phase H2S concentration of a fuel storage tank nor does it provide any indication of the liquid phase H,S concentration.
5.4 Test Method D602 1 does measure the H,S concentration of H,S in the liquid phase, however it requires a laboratory and a skilled operator to perform the complex procedure and calculations, and does not otTer any reproducibility data. This test method (D762l) offers a 15 mm automated test, simplicity. full precision, and a degree of portability.
5.5 l-12S concentrations in the liquid and vapor phase attempt to reach equilibrium in a static system. However, this equilibrium and the related liquid and vapor concentrations can vary greatly depending on temperature and the chemical composition of the liquid phase. The equilibrium of the vapor phase is disrupted the moment a vent or access point is opened to collect a sample.
6. Apparatus
6.1 General—The apparatus, as detailed in Annex A 1, comprises an air pump. test vessel, heating jacket, filters. H,S specific detector, integral computer, automatic solenoid valves and gas flow detectors.
6.1.1 Procedure A requires the use of a vapor phase processor capable of cooling a specific filter cartridge (see 7.4) to —20°C ± 2°C.
6.2 Analytical Balance, single pan or double pan balance capable of weighing to the nearest 0.001 g.
6.3 Syringe or Burette, able to dispense 20 mL for introduction of the diluent oil (see 7.1), accuracy ± I %.
6.4 Refrigerator (optional), for storing the test sample (see 8.3). The refrigerator shall he of a type suitable for storing flammable, volatile materials.
6.5 Oi’enlWater Bath (optional), for warming the sample to
40 °C with an accuracy of ±2 °C (sec 8.4.1.1). The oven shall be of a type suitable for use with volatile materials.
6.6 Pipette, I mL positive displacement pipette, for the introduction of the test specimen. The accuracy as stated by the manufacturer should he typically ±0.25 %.ASTM D7621 pdf download.