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.
Exploring a new catalytic solution for improving efficiency and energy balance in sulfuric acid plants
White paper VK38+: Innovating on existing catalyst solutions
Increased attention on emissions during startup of sulfuric acid plants calls for better understanding of the dynamics of the plants and the phenomena controlling the emissions of SO2 and acid mist.
White paper Understanding dynamics and emissions during sulfuric acid converter startup
Sulfuric acid plants often encounter transient phenomena such as emission spikes during unsteady operation. Emission spikes and related phenomena can be understood and predicted by considering the sulfur content of the V2O5-based catalyst used in sulfuric acid converters.
White paper Dynamic simulations Sulfuric acid
Profit margins are slim in the sulfuric acid business, and plants that want to succeed need feedstock flexibility, high conversion rates, low energy consumption and high reliability. They also have to meet increasingly strict limits on SO2 emission
Brochure The profitable way to sulfuric acid
VK-7XX LEAP5™ is the latest catalyst developed on the basis of the unique LEAP5™ techology. It is optimized for operation in converted strong gasses at 370-440°C/700-825oF, which is typical for the final passes of single-absorption plants
Brochure High activity at low temperature
Managing a sulfuric acid plant can be challenging on the best of days, but what happens when real trouble arises? Sudden changes in pressure drops or emissions may force a decrease in production or even a full shutdown for repairs. And even when everything is working, catalyst activity changes over time – and so should a plant’s operating conditions.
Brochure Troubleshoot, Monitor & Plan Ahead
The Guizhou Kailin Fertilizer company had two sulfuric acid plants in Guizhou, China that were experiencing similar problems. A severe pressure drop build-up over the first catalyst bed was increasing energy costs and eating away at margins. Dust was forcing the plant to shut down for unplanned screening maintenance and catalyst replacement.
Customer case Guizhou Kailin sulfuric acid plants combat dust to eliminate unplanned downtime and improve Opex
In 1997, VK69 was installed in the fourth pass of a large 1460 MTPD sulphuric acid plant in Asia. The plant burns elemental sulphur and the four-bed converter has intermediate absorption after the third pass.
Customer case Reduce SO2 emissions - Less than 100 PPM SO2 in the stack
The Chinese government has been tightening SO2 emissions regulations for years. In many regions, the targets are now set at 70 PPM. While some plants depend on conventional catalysts and scrubbers, Xiangguang Copper in Shandong Province wanted a long-term approach. the contacted Topsoe to find a catalyst solution to help them comply with stricter emission controls,
Customer case Yanggu Xiangguang copper takes new approach to meet emissions standards of 70 PMM SO2
Nuova Solmine, a sulfuric acid plant in Scarlino, Italy, had been operating with SO2 emissions averaging about 280 PPM. When new regulations capped emissions at 224 PPM; the plant had to make a choice: reduce production of sulfuric acid, resulting in loss of profit, or find a way to reduce emissions without cutting production.
Customer case Nuova Solmine cuts SO2 emissions by 50%, complying with emissions regulations without reducing production
Incitec Pivot's sulfuric acid at Mount Isa, Australia needed more sulfuric acid than they could produce, but transport of sulfur or sulfuric acid to the company's outback location was expensive.
Customer case With Topsoe's Leap5™ catalyst, Australia's Incitec Pivot increased production & reduced emissions
Topsoe has developed a new improved dust protection catalyst in the size of a 25 mm daisy in the proven VK catalyst formulation.
Leaflet New improved dust protection catalyst for sulphuric acid plants
Topsoe’s VK-701 LEAP5™ is optimized for operation in converted strong gasses at 410-460°C/770-895°F, which is typical for the 3rd pass of 3+1 double-absorption plants. At these conditions, VK-701 shows significant activity advantages compared to existing potassium and cesium-promoted catalysts.
Leaflet Proven SO2 emissions reduction in high temperature environments
/MAVO.jpg "Marie Vognsen")