What to do if the sulfur content in the propylene column of the gas processing unit remains high?
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Our unit has a gas separation unit with an annual production capacity of 150,000 tons. Recently, the sulfur content in the feedstock has been within normal limits; however, the sulfur content of C4 at the bottom of the depropanization tower reached 170 PPM, while it was around 100 PPM at the top of the tower. As a result, the sulfur content in the propylene produced by the propylene tower exceeded the specified limits. Upon inspection, the desulfurization system was functioning properly, and the parameters of the feedstock buffer tank were also within normal ranges. I really can’t figure it out. Please give some feedback. Thank you
What method is used to analyze sulfur content?
The desulfurization system is working properly, but what about the LPG desulfurization and dehydration system? What are the levels of thiol and total sulfur in the raw material?
Haha, who are you? It’s strange too – with just that little amount of raw material being reused day after day, how can the sulfur content still be high? If operating at full capacity, it’s likely that just one breath of liquefied gas would cause sulfur poisoning!
It is recommended to conduct an analysis first; it is likely that you are using the microcoulomb method. In this method, errors can easily occur in all three steps: carrier gas combustion, solution absorption, and potential detection. If conditions permit, it is recommended to use chromatography for comparison. Check liquefied gas desulfurization again, observe the operation of pre-alkaline washing and hydrodesulfurization, and take samples at the refining outlet for analysis. Check the process to see if desulfurized liquefied gas might have leaked into the gas section. If air pollution can only be brought to acceptable levels through replacement
Use products to remove carbonyl sulfide – let’s see how it works
Reply to 1# Ningxia Huakai123: It seems there’s a problem with the desulfurization of liquefied gas; hydrogen sulfide isn’t being removed properly； During the normal gas-phase process, organic sulfur compounds such as thiolthiols generally accumulate in the C4 fraction, while hydrogen sulfide rises into the propylene fraction
I think the problem lies with your liquefied gas desulfurization system. You could check the hydrogen sulfide level after desulfurization, as well as the levels of carbonyl sulfide, thiols, hydrogen sulfide, and total sulfur after deodorization This way, problems will definitely be detected