液空硫回收分析方法中英文版..docxVIP

GWS 7PrincipleThe hydrogen sulphide absorbed in the elementary sulphur is expelled from a melted sample using nitrogen containing ammonia . ammonia accelerate the expulsion of the hydrogen sulphide . The H2S is absorbed in the wash flasks filled with KOH and converted to K2S(1) . the wash flask arranged between with 0.5 n H3PO4 servers to separate elementary sulphur from the gas steam . the K2S-content of KOH is then determined potentiometrically with silver nitrate(2).2KOH+ H2S-K2S+H2O(1)K2S+2AgNO3-Ag2S+2KNO3(2)Sampling30-50g liquid sulphur is poured into the weighted sample vessel at the sampling location . the vessel is immediately closed gastight and weighted again in the laboratory . The difference is the quantity of the sample.Equipment and ChemicalsEquipmentsamplevessel: collecting vessel with nozzles and screw cap , see Item 3 on Figure 1 : content:30ml,thread sized 24,suitable for tubes dia . 7.5-9.0mm,Overall length :200 mm.Oil bath with thermostatFlow meter ~2-10 I N2/HSealDrying tube,U-shape1 wash flask with sphericak stopper2 wash bottle with frittered stopper(D 1)TitratorSilver/silver sulphide electrodeGlass electrode or other reference electrodeChemicalsAmmonium carbonate “purest”Potassium hydroxide solution , p.a.35% aqueous solutionPhosphoric acid p.a.0.5 nSilver nitrate 0.01 nNitrogenProcedureThe time between taking the sample and making the analysis ought to be kept as short as possible to keep the H2S losses by reaction of H2S with the existing SO2 to sulphur small.The sulphur sample is melted in the oil bath at 130-140°and stripped for 2 hours with nitrogen containing about 0.3 vol.% NH3 after flowing through a drying tube filled with ammonium carbonate. The N2 stream is adjust in such a way that 0.1-0.2 l/h nitrogen flow through . The hydrogen sulphide removed with the nitrogen is absorbed in the two KOH wash flasks . The H3PO4 wash flask only serves to remove elementary sulphur from the gas stream . Elementary sulphur is to be prevented from e