Why is hydrogen sampling and analysis conducted during the hydrocracking emergency pressure relief test, and what is the purpose?

I’ve heard of this for the first time. During an emergency pressure release, everyone is busy dealing with that situation; there’s no time to take samples. Could it be to check the carbon monoxide level inside? But that seems unlikely. It might be to test the hydrogen sulfide content. If low-sulfur paraffinic crude oil is used in the hydrocracking process, then during an emergency pressure release the hydrogen sulfide content in the circulating hydrogen is low, and the purity of hydrogen is high. Additionally, if the bed temperature has not yet dropped, it could lead to catalyst reduction.

This post was last edited and replied to by lijianhuai on 2011-8-3 at 16:02. Reply to 2# zhg20051007: When work started in Guangxi last year, emergency pressure relief tests were carried out, along with sampling and analysis of cyclic hydrogen; the results were as follows: C6: 0.01, CO2: 0.06, O2: 0.32, N2: 1.68, H2: 97.93; other components were not detected. The pressure release rate is related to the gas molecular weight and the gas volume. Therefore, sampling and analysis are required to calibrate the orifice plate, using the following formula: 3. Adjust the corresponding pressure release rate based on the operating conditions during use and the properties of the gas, with dP/min equal to the initial pressure release rate in psi/min or kg/cm2/min. Σ(V/ZT) = the sum of the volumes of gas in all the equipment and pipelines within the high-pressure circuit, divided by temperature and the compression coefficient, expressed in ft3/°R or m3/°K. Assume that the volume of the reactor is the shell volume. It is assumed that the liquid level in the container during operation is at the normal level. K= the specific heat capacity ratio Cp/Cv of the high-pressure vapor at high temperatures. Z = Compression coefficient of high-pressure vapor. M = the molecular weight of the high-pressure vapor. Use the molecular weight at the initial pressure release during the middle stage of operation. Ts= High-temperature value, °R or °K. The initial pressure relief temperature is used during the middle stage of operation.

Reply to 3# pspc0293: I agree with what was said on the 3rd floor. The purpose of the emergency pressure relief test is, first, to determine the speed at which pressure can be relieved, and second, to check whether the system’s piping installation meets the required standards. The purity of the recycled hydrogen should be above 85% based on the actual operating conditions