Advantages and disadvantages of iron oxide/zinc desulfurization compared to activated carbon desulfurization

Could you explain it in detail? I know that generally, iron oxide and zinc oxide require relatively high adsorption temperatures, with iron oxide tending to turn into powder easily

Advantages of iron oxide desulfurizer: high hydrophobicity, low cost, and the ability to be regenerated in air at room temperature. It can remove H2S from gas streams under anaerobic conditions and can operate at room temperature (mainly used for preliminary desulfurization). It results in lower equipment investment costs and simpler operation; therefore, from a cost-performance perspective, it is quite suitable for natural gas desulfurization. Thanks to improvements over the past few years, the water resistance and desulfurization accuracy of iron oxide have been greatly enhanced, enabling it to be used in desulfurization projects in most industries. Disadvantages: It has poor strength as an iron oxide, tends to crumble when exposed to water, offers low precision in desulfurization; in a reducing atmosphere at high temperatures, carbon deposition can occur. Moreover, iron oxide must be used under alkaline conditions, and the pH level can be maintained by adding soda ash. Since iron oxide must remain in a hydrated form, water is usually added to it; this also facilitates the addition of soda ash. Furthermore, to prevent the evaporation of the iron oxide solution, the reaction temperature should not be too high. Advantages of activated carbon desulfurization agents: Activated carbon materials possess polarity, hydrophobicity, as well as high chemical and thermal stability. They can be activated and modified. Combined with their catalytic capabilities, loading capacity, and reduction properties, along with their unique pore structure and surface chemical characteristics, these features give activated carbon excellent inherent qualities as a desulfurization and denitrification agent ； It can remove SO3, which is difficult to remove by wet methods, with a very high removal rate for SO3 ； Disadvantages: low sulfur capacity, slow desulfurization rate, frequent regeneration ； Water washing for regeneration requires a large amount of water and can lead to secondary pollution ； And activated carbon is prone to wear during heating regeneration ； In practical use, the injection of ammonia increases the adhesion force of activated carbon, resulting in uneven airflow distribution within the absorption tower. Additionally, the presence of ammonia leads to problems such as pipeline blockage, corrosion, and secondary pollution ； Activated carbon does not have high strength, and it suffers significant wear and tear when adsorbing harmful substances; this poses certain limitations for desulfurization processes. Additionally, its market price is relatively high ； Furthermore, the use of activated carbon desulfurization agents must take place under aerobic conditions, with the optimal temperature ranging from 30 to 50°C. Zinc oxide desulfurizer: Compared with iron oxide desulfurizers and activated carbon desulfurizers, zinc oxide desulfurizers currently exhibit stronger desulfurization capabilities in the industry. High sulfur capacity ； Higher desulfurization accuracy ； In particular, zinc oxide desulfurizers with copper/nickel added exhibit better desulfurization performance and a longer lifespan ； High adaptability ； Suitable for normal temperature, medium temperature, and high temperature operating conditions ； High mechanical strength, good water resistance, and resistant to pulverization ； It does not cause secondary pollution in actual industrial applications ； Its economic benefits are far higher than those of activated carbon desulfurization agents. At present, zinc oxide desulfurization agents have become the dominant choice in industrial applications.