Abnormal phenomena of medium-temperature iron oxide in fine desulfurization
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The medium-temperature iron oxide used for fine desulfurization in our factory stopped absorbing hydrogen sulfide within two months of use after reduction, and the hydrogen sulfide measured at the outlet of the iron oxide was higher than the imported iron oxide. Our factory shares three iron oxide tanks, and this phenomenon has already occurred in two tanks. There is also a phenomenon that the oxygen content in the gas in the three tanks is gradually increasing. According to the manufacturer, this phenomenon has not been found in other factories, and after the iron oxide is saturated with hydrogen sulfide, it will no longer absorb hydrogen sulfide, and there should be no high hydrogen sulfide at the outlet. Unless oxygen is present or a large amount of water is present. Our factory uses medium-temperature iron oxide after iron-molybdenum hydrogenation and conversion. The iron oxide has a good effect in the early stage of use, but the use time is short and the sulfur capacity use time cannot be reached, and the difference is large. The oxygen content that occurs during the use of iron oxide gradually increases, and the total oxygen content is about 0.1%. Compared with the oxygen content after iron-molybdenum hydrogenation and conversion, the oxygen content is higher. The main problem here is what is the reason for the undue sulfur release of iron oxide and how to solve this problem.
Our factory also had this phenomenon in the past, and sometimes it cannot be explained. We have now replaced all medium-temperature iron oxides with medium-temperature zinc oxide. Even though the investment is relatively large, the total sulfur at the fine removal outlet is also qualified. We now have four units of medium-temperature vaporized zinc. It is recommended that you also change to zinc oxide. Sometimes manufacturers cannot explain this phenomenon. After all, the composition of coke oven gas is too complex. My opinion is that the oxygen content in your coke oven gas may be high, because sometimes the laboratory data is inaccurate unless you install an online oxygen analyzer at the outlet of the gas cabinet.
This is the phenomenon of catalyst releasing sulfur. The more air is added, the higher the temperature will be, and the higher the sulfur will be. This phenomenon can take up to 2 days to reverse. This is caused by the imbalance between the amount of air added to the steam and the distillation tank before starting normal temperature hydrolysis. For example, air is not added to the catalyst to adsorb a large amount of hydrogen sulfide, and the hydrogen sulfide is not converted into elemental sulfur for adsorption, or the steam is too foamy and is released under certain conditions. Just release the anti-bar and it will be fine. Add air and steam in an appropriate amount. Your flow meter is definitely not accurate :(