SulfoMax® catalysts for Sulfuric Acid Plants

The conversion of sulfur dioxide to sulfur trioxide is the catalytic step in the production of sulfuric acid. Süd-Chemie’s SulfoMax® (C 116) series of catalysts feature different formulations and innovative shapes, covering all operating conditions in the sulfuric acid process. SulfoMax® catalyst is optimized to offer lower screening losses with uncompromised activity, high mechanical strength and better gas distribution. Whether the preferred outcome is to reduce emission, increase productivity, maximize energy recovery, decrease pressure drop or extend catalyst lifetime, SulfoMax® is the product of choice.

SulfoMax® catalyst which has more than 175 global references comes in different shapes and sizes to meet in myriad of process and operating conditions. All catalyst types are specifically designed to achieve optimum performance under varying process conditions.

SulfoMax® RR

SulfoMax® RR is an all-purpose catalyst with its unique formulation combined with ‘Ribbed’ ring form providing better overall conversion across the entire temperature range of a typical sulfuric acid converter operation. Its physical integrity benefits the user in terms of reduced screening losses year on year thereby offering increased life while maintaining optimal activity. 

SulfoMax® HV

This High Vanadium catalyst is recommended for loading in passes before the intermediate absorption in DCDA plants. Its enhanced active ingredient offers improved conversion at higher SO3 environments. HV can also improve conversion in Single absorption plants where there is no intermediate removal of SO3.

SulfoMax® CS/ CV

Cesium promoted catalysts offer multitude of benefits due to its low temperature activity.  SulfoMax® Cs/CV when installed in the first/final pass helps to achieve higher equilibrium conversion with its ability to function at much lower temperature at the gas inlet.  Several other benefits include

SulfoMax® GRR

Despite the use of pure Sulfur and multiple steps of molten sulfur filtration, dust carryover to the first catalyst bed of the converter is practically unavoidable in most cases. The dust/foreign particle deposition onto catalyst bed over time, leads to an increase in pressure drop and reduction of throughput, besides causing mechanical and chemical deactivation/poisoning of the catalyst. The function of SulfoMax® GRR is to capture the dust while keeping the gas flow path unrestricted. As a result, the rate of pressure drop evolution is kept under control, thereby increasing the campaign life of the catalyst. Due to its geometrical advantage, in certain cases, a layer of GRR can effectively replace the hold-down inert layer.  GRR is available in two sizes to suit the functional catalyst size. 

SulfoMax® EV

The latest addition to the SulfoMax® family, the SulfoMax® EV catalyst is active at temperatures as low as 360°C and shows very high conversion efficiency, especially at low SO2 concentrations. EV finds its application especially in the final passes after the intermediate absorption where it helps reduce emissions to a greater extent. Consequently, SulfoMax® EV paves the way for new plant designs that can operate at very low inlet temperatures enabling improved heat recovery possibilites.

Wet-gas Sulfuric Acid (WgSA) Process

In conventional sulfuric acid processes, the process gas is dry in nature with the help of the drying step in the Sulfur burning process and dehumidification in metallurgical off-gas based processes. In a Wet gas based Sulfuric acid process, commercial grade Sulfuric acid is produced from a moisture laden Sulfur dioxide gas generated from various sulfurous streams.

In the presence of moisture in process gas, Conventional V2O5 catalysts are prone to degrade quite soon. To withstand harsh process conditions, mainly moisture, a formulation needs the Wet-gas Sulfuric Acid process. SulfoMax® W series catalysts are developed to sustain optimal conversion despite high moisture present in the process gas while retaining its active ingredients for a longer catalyst life.

SulfoMax® W series catalysts are put to use in several Wet-gas sulfuric acid plants globally and have operated satisfactorily. This catalyst is available in all shapes. In specific cases, this catalyst is also promoted with Cesium for low temperature activity.

SulfoMax® WRR

Due to unique chemical ratios, WRR can be used in all the beds of a WgSA plant. Practical experience shows that catalyst activity is sustained for more than 4 years without any significant pressure drop evolution.

SulfoMax® WCV

Cesium promoted Wet gas sulfuric acid catalyst, WCV, helps in improved equilibrium conversion despite high moisture content in the gas, with further benefits such as low SO2 at stack, faster plant startups, better energy recovery, lower quench air requirement.

SulfoMax® W-GRR

W-GRR on top of the first bed helps in prolonging the campaign life of the catalyst by absorbing effects of process upsets, moisture/mist condensation, and the carryover of foreign material onto the catalyst.