Revision of the sulfuric acid plant

After intensive planning and three weeks of focused work, the overhaul of our sulfuric acid plant was successfully completed. The scheduled plant overhaul is one of the most important building blocks for long-term operational safety, plant availability, and product quality. Since a sulfuric acid plant can only be completely shut down at longer intervals, this measure is of particular importance.

Clear Goals for Safe and Reliable Plant Operation

The primary goal of the overhaul was to perform all safety-related, legally required, and TÜV-compliant inspections. Only through regular inspections, maintenance, and the replacement of critical components can safe, efficient, and compliant operation be ensured.

The plant was scheduled to resume operations after three weeks. Thanks to detailed preparation and the excellent cooperation of all parties involved, this goal was also successfully achieved.

Extensive Modernization and Replacement Measures

A key focus of the overhaul was the replacement of the K5 drying tower. This central plant component dated back to 1981 and was replaced with a modern tower. The new drying tower is constructed from highly acid-resistant materials such as SX stainless steel and features special acid-resistant lining. These materials provide excellent corrosion protection while also helping to minimize metallic impurities in the final product. This ensures the high purity of the produced sulfuric acid over the long term.

In addition to the drying tower, other important modernization measures were implemented:

• Replacement of the absorption pumps dating from 1981
• Construction of a new, modern feedwater tank
• Replacement of the approximately 66-meter-long fiberglass-reinforced plastic (FRP) chimney pipe due to existing leaks
• Replacement of worn-out valves and piping
• Replacement of various measurement and control system components
• Maintenance of key plant components such as blowers and steam turbines

Successful collaboration with external partners

This overhaul marked the first time we collaborated with Smart Scope, an engineering firm specializing in sulfuric acid plants. Although additional effort was initially required to familiarize ourselves with the plant’s specific characteristics, the collaboration proved extremely successful. The coordination of the numerous trades involved also worked exceptionally well. These included, among others:

• Metalworking
• Piping
• Plastics fabrication
• Electrical engineering
• Process control engineering
• Furnace construction

Coordination between internal employees, external contractors, and project managers therefore presented a particular organizational challenge. The collaboration between the operations team, foremen, project managers, and safety coordinators ensured that all work could be carried out efficiently and safely.

Team Spirit and Innovative Solutions as Keys to Success

A key factor in the project’s success was the exceptionally good cooperation among all parties involved. In-house specialists, plant operators, tradespeople, and external service providers worked closely together, all striving toward the common goal of a safe and on-time recommissioning. A container solution, used for the first time, was particularly well received. The modern containers provided separate changing areas, showers, and break rooms for the numerous tradespeople and contractors. This improved workflows, shortened travel distances, and significantly increased comfort on the construction site.

Looking Ahead: Continuous Improvement for Future Overhauls

Even though the overhaul was extremely successful, further opportunities for optimization have already been identified. For future plant shutdowns, safety briefings at the plant gate will be organized more efficiently, signage for material deliveries will be improved, and suitable safety personnel will be selected and tested even earlier. In addition, standardized work packages for recurring tasks are intended to reduce planning effort and further enhance quality. At the same time, preparations are underway for the replacement of other plant components that have been in use for many years.

For the new core team led by Frank Rensch and Marcel Ruiter, this overhaul—carried out in collaboration with the newly selected engineering firm—was an intensive but extremely successful first test of their capabilities. The project impressively demonstrates how careful planning, high safety standards, modern maintenance concepts, and strong teamwork can ensure the long-term performance of a sulfuric acid plant.