Why add an oxygen leakage protection catalyst

Gamma alumina becomes sulfated and loses its activity in the presence of peroxides.

In previous catalyst loading schemes, oxygen-leak prevention catalysts were usually required. However, with the improvement in burner design and the enhancement of catalyst performance, almost no installations use such catalysts nowadays; only a small number of imported installations still employ this approach.

In my opinion, if the process gas is reheated without using a regenerative furnace method and sulfur removal during shutdown is well controlled, oxygen leakage generally does not occur.

The anti-oxygen leakage catalyst is used to prevent improper air distribution in the sulfur production furnace mentioned earlier, which could allow a small amount of oxygen to enter the primary converter. This oxygen not only promotes sulfation but may also cause elemental sulfur in the bed to catch fire, leading to an increase in temperature in the bed and damage to the catalyst. The quantity is determined by the volume of the converter.

Thank you. I’ve learned it.* . . . .

There are generally two types available online, each with its own advantages and disadvantages. . . . . . HZ-402 TiO2-based sulfur recovery catalyst is a new generation of TiO2-based anti-sulfatization sulfur recovery catalyst. This catalyst exhibits higher catalytic activity for the hydrolysis of organic sulfides as well as the Claus reaction between H2S and SO2. It is not sensitive to \"O2 leakage\" poisoning and can meet the requirements for high space velocities; its overall performance and technical specifications are at the international advanced level. ■ Excellent mechanical strength ■ High activity ■ Good selectivity and activity stability ■ Long service life (reusable) The HZ-402 TiO2-based sulfur recovery catalyst can be used in the entire bed of any reactor in a sulfur recovery unit, or it can be used in combination with other catalysts of different functions or types in a layered configuration. When using layered packing, the HZ-402 catalyst can be packed in the lower part of the first reactor bed where the temperature is higher, accounting for about 1/3 to 1/2 of the total bed volume, to facilitate the hydrolysis reaction of organic sulfides. ■ Temperature: 220°C–350°C ■ Pressure: Atmospheric pressure – 0.2 Mpa ■ Space velocity: 200–1000 h-1 (dry gas). The HZ-403 sulfur recovery catalyst is a dual-function catalyst with high Claus activity and oxygen removal capabilities; its physical and chemical properties as well as technical specifications are at the international advanced level. When used in combination with the HZ-401 Al2O3 catalyst or the HZ-402 TiO2-based catalyst, under the same equipment and process conditions, the total sulfur conversion rate can be increased by approximately 1% to 1.7%; it is particularly suitable for use in sulfur recovery units where the H2S content or flow rate in acidic gases varies significantly. ■ Excellent mechanical strength. ■ High activity and excellent low-temperature conversion activity. ■ Good selectivity and stability of activity. ■ Long service life. The HZ-403 sulfur recovery catalyst is suitable for Claus sulfur recovery units in fields such as petrochemicals and coal chemicals; it can be used in the entire bed of any stage of the Claus reactor, or it can be used in combination with other catalysts of different functions or types in a layered configuration. When using layered packing, the HZ-403 catalyst can be placed in the upper part of the reactor bed, occupying at least 1/3 of the total volume of the bed. ■ Temperature: 220°C-350°C ■ Pressure: Atmospheric pressure-0.2Mpa ■ Space velocity: 200-1500h-1

How could the leaking catalyst be Fe ions?

Oxygen leakage-proof (not air leakage) catalysts usually contain divalent iron ions, and their reducing property is utilized to prevent oxygen leakage.

This post was last edited by SulfurBlind on 2015-9-11 at 14:23. I found such a reaction equation to explain the mechanism of oxygen prevention: Fe2(SO4)3 + O2 + 2H2S → 2FeS2 + SO2 + 2H2O. Does iron sulfite get formed from the first two products, and then the cycle repeats? But this oxygen barrier agent gives me the impression of being weak and prone to crumbling. It’s not a big issue now as PPM-grade materials are less prone to oxygen leakage, and the three catalyst manufacturers no longer promote such products. Don’t pretend this.

Oxygen-leaking catalysts were originally designed to address the problem caused by O2 when Al2O3 is used as a catalyst: O2 reacts with Al2O3 to form SO2, which in turn leads to the formation of AL2(SO4)3 and thus a loss of catalyst activity. Adding ferrous ions FeS2 effectively consumes the excess O2, and this process repeats itself. These days, TiO2 is often used as a catalyst, and the sulfation effect can be basically ignored; however, its price is about three times higher... :) I hope this is useful to you···