Qualification standards for nitrogen purging of hydrogenation units
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Let’s discuss: What standards should be met for sampling and analysis after purging?
It is required that the oxygen and combustible gas contents in the equipment are less than 0.5%. Different devices have different specific requirements.
Oxygen content is less than 0.5%, flammable gas is less than 1%
The oxygen content is required to be less than 0.5% when starting work, and the combustible gas content is required to be less than 0.5% when stopping work.
Gas sampling analysis: The content of the flammable medium must be less than 10% (volume) of the lower explosive limit of the mixture of the medium and air.
Oxygen content≯0.5%, flammable gas≯0.5%
In addition to testing for oxygen and hydrocarbons, it is also necessary to test for hydrogen sulfide content less than 10%.
The qualified standard for starting N2 replacement is 0.6% oxygen content, and H2 replacement is 0.2%.； The shutdown explosion analysis showed that N2 was replaced by oil and gas + H2 and the explosion passed the test.
I would like to know the source of the 0.5% (v/v) you are talking about?