A method and apparatus for the on-stream analysis of total sulfur and/or nitrogen in petroleum products

摘要

An improved on-stream analyzer (1) for monitoring sulfur or nitrogen content of liquid petroleum or beverage products is described. It consists of the following main components: a sample injector, preferably 'Fast Loop', for injecting predetermined fixed volumes of the liquid into a thermal oxidizer (pyrolyzer) at a preset, controlled rate, a thermal oxidizer (280) to thermally oxidize the sample at a temperature of about 1050°C, sample conditioner to control the relative humidity and temperature of the resulting gas mixture, an electrochemical cell (560) sensitive to sulfur dioxide (SO2) or NO to measure the concentration of SO2 or NO in the gas mixture, and a programmable logic controller (PLC) to calculate the sulfur content of the original sample and manage the analyzer. One preferred apparatus and method comprises a catalytic or thermal converter to selectively remove the nitrogen-containing interferant without affecting the sulfur content. A second preferred apparatus and method comprises a chemical scrubber to selectively remove the nitrogen-containing interferant from the gas stream without affecting the sulfur content. Although the analyzer is designed primarily for monitoring sulfur content, it is recognized that the same equipment can be used to analyze any sample having a suitable viscosity and capable of being thermally oxidized under the conditions specified.