The WSA process is a wet gas catalytic process. The concentrated sulfuric acid is produced by condensation from a wet process gas. Drying of the process gas prior to treatment in a WSA plant, therefore, becomes superfluous, hence generation of wastewater and loss of sulfur are avoided. The purpose of the first step in the process is to produce an SO2 gas at the operating temperature of the oxidation catalyst in the SO2 converter. If the sulfur in the feed is SO2, only a simple preheating is required. Other sulfurous feeds are oxidized to SO2 by combustion and then cooled to the optimum catalytic conversion temperature in a waste heat boiler. The excess heat from this operation is recovered as steam. The catalytic conversion of SO2 to SO3 takes place in one or more catalyst beds. Reaction heat is recovered between the catalyst beds by superheating of steam. After the last conversion step, the gas is cooled and the SO3 reacts with water vapor to form gas-phase sulfuric acid. The process gas is finally cooled by a countercurrent flow of air in the proprietary WSA condenser. Clean gas exits at the top of the WSA condenser and the sulfuric acid is collected in the bottom section from where it is cooled and sent to storage. Hot air generated in the WSA condenser may be used as preheated combustion air to ensure optimal energy efficiency.
Catalysts
Catalysts
The performance catalysts we supply for this application are listed below.
- Catalysts
VK-WD
VK-WD is optimized for lean SO2+SO3 gases, such as in a SNOX™ plant or in the bed(s) after the intermediate condenser in a WSA-DC plant. - Catalysts
VK-WH
VK-WH is a cesium-promoted catalyst designed for continuous operation down to 370°C/700°F in medium- to high-strength SO2+SO3 gasses. A top-layer of VK-WH can significantly improve operating flexibility by widening the bed temperature control window, especially in plants struggling with fluctuating... - Catalysts
VK-WL
VK-WL is a cesium-promoted catalyst designed for continuous operation down to 370°C/700°F in lean SO2+SO3 gasses (less than approximately 2 mole%). At these conditions, VK-WL offers unmatched high activity throughout the entire operating temperature range. The very high activity provides the... - Catalysts
VK-WSA
The VK-WSA formulation offers excellent activity over a wide range of operating conditions and can be used in any bed of a WSA or WSA-DC converter. VK-WSA is available in the 12 mm Daisy shape and as a dust-protection catalyst in the large 25 mm Daisy shape. 12 mm Daisy: improved energy efficiency... - Catalysts
VK-WSX
The VK-WSX formulation was developed to offer higher activity in SO2 gasses that are more than 90% converted. Typically VK-WSX is used in the last bed of a WSA converter. For this service, VK-WSX is more active than VK-WSA and even more active than cesium-promoted VK-WH catalyst. The high activity...
Equipment
Equipment
The proprietary equipment we supply for this application are listed below.
- Equipment
Integrated Sulfuric Acid Concentrator (ISAC)
The ISAC is a small, packed column placed underneath the WSA condensers in WSA and SNOX™ plants. The purpose is to boost the acid concentration from what can be produced in the WSA condenser, e.g. 98%, to e.g. 98.5%. For special applications of sulfuric acid, a very high acid concentration is... - Equipment
Sulfur Oxides Low VElocity filter (SOLVE)
The SOLVE filter is a special acid mist filter with an injection of hydrogen peroxide solution that oxidizes residual SO2 to SO3. The SO3 then immediately reacts with water vapor in the gas to form sulfuric acid that is captured in the low-velocity mist filter. SOLVE filters are supplied only in... - Equipment
Sulfuric Acid Condenser
The WSA condenser in WSA and SNOX™ plants cools the process gas with atmospheric air, typically from 280°C to 100°C. This first makes the SO3 in the process gas react with water vapor to form the sulfuric acid vapor, and secondly, the sulfuric acid vapor condenses to form the sulfuric acid liquid... - Equipment
Sulfuric Acid Cooling System
The acid cooling system of WSA and SNOX™ The acid cooling system of WSA and SNOX™ plants performs a two-step cooling of the hot product sulfuric acid from the WSA condenser. First, the hot acid is quenched with cold acid, before going to a pump reservoir. Then the acid is pumped through the acid...
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Project development
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Project development
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