ISO 6326-5:1989 pdf download.Natural gas — Determination of sulfur compounds — Part 5: Lingener combustion method.
ISO 6326-5 specifies a method for the determination of total sulphur in natural gas. It is applicable to gases with sulphur contents between 0,5 mg/m3 and 1 000 mg/m3. With a total sulphur content of more than 0,1 mg sulphur in the absorption solution, visual titration with an indicator can be chosen, whereas for lower contents turbidimetric titration is preferable.
3 Principle
A measured volume of gas is burnt with air at atmospheric pressure in a glass combustion apparatus. The resulting sulfur oxides are converted into sulfuric acid by absorption in ydrogen peroxide solution. Depending on the sulfur content of the test gas, the sulfate ions in the absorption solution are determined using either visual titration with an indicator or tur bidimetric titration.
4 Reagents and materials
During the analysis, use only reagents of recognized analytic grade and only distilled water or water of equivalent purity.
6 Procedure
6.1 Preparation for combustion
Draw air, which if necessary should be cleaned of sulfur im purities with activated carbon (4.2) and/or absorbing liquid (4.3)，through the combustion apparatus with the aid of the vacuum pump (G)， with a required volumetric flow about 20 I/min. Remove the burner (5. 1.3)and pour sufficlent hydrogen peroxide solution(4.1) into the receiver(5.1.1) to rise around the flame tube (5.1.2) to the height of the burner tip throughout the period of combustion. After connection of the cooling water, the combustion apparatus is ready for use.
6.2 Combustion
With a preliminary pressure of about 2 kPa on the U-tube manometer(D)， ignite the gas at the removed burner. Carefully introduce the burner, with the flame directed downwards, into the flame tube and note the reading on the gas meter (E).The air flow and cooling water flow may have to be adjusted.
7 Analytical determination
With a total sulfur content of more than 0, 1 mg sulfur in the ab- sorption solution, visual titration with an indicator can be chosen, whereas for lower contents turbidimetric titration is preferable
7.1 Determination of sulfur content by visual titration.
7.1.1 Reagents
During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity.
7.1.1.1 2-Propanol (Isopropyl alcohol)
7.1.1.2 Barium perchlorate, standard volumetric solution.ISO 6326-5:1989 pdf download.