A Comparison of Sulfur Selective Detectors for Low Level Analysis in Gaseous Streams Application

A comparison of four selective detectors for analysis of single-digit ppb level sulfur is described. A dynamic blending system is used for point of use preparation of low level gaseous mixtures of eight sulfur compounds including H 2 S, COS, CS 2 and selected mercaptans in helium, ethylene, propylene, and carbon dioxide. The criteria to consider for selecting the best detector for an application depends on many factors including, sensitivity, selectivity, stability, and ease of use. Guidelines for making the best detector choice are discussed. The Atomic Emission, Flame Photometric, Pulsed Flame Photometric, and Sulfur Chemiluminescent detectors are included in the study. A Comparison of Sulfur Selective Detectors for Low Level Analysis in Gaseous Streams Application Introduction The use of sulfur selective detectors in gas chromatography has grown in recent years with the increasing industrial demands for sulfur measurement. A major driving force has come from the hydrocarbon processing industry where the need for lower level more reliable sulfur measurements is intensifying. Regulations on sulfur levels in fuels continue to tighten. The need for low level sulfur measurements exists in nearly all segments of the chemical industry. Examples include the analysis of beverage grade CO2 and the determination of ordorants in natural gas. In this paper, the characteristics and performance of four types of sulfur detectors will be compared with example applications used to demonstrate their operation under real-world conditions. The detectors include the AED (Atomic Emission Detector), SCD (Sulfur Chemiluminescent Detector), PFPD (Pulsed Flame Photometric Detector), and FPD (Flame Photometric Detector). The Significance of Sulfur Most sources of light hydrocarbons contain sulfur compounds that can be corrosive to pipes and equipment. The emission of undesirable odors caused by volatile sulfur compounds in intermediates and final products can have serious economic impact. Perhaps the most important consequence of sulfur is its’ detrimental effect on a variety of catalysts used for processing and conversion of light hydrocarbon streams. Also, full compositional determinations of LPG (Liquefied Petroleum Gases) and propene mixes are required frequently where pricing of the end product is based on quality. Gas Chromatography