Sulfuric Acid Process Gas Recirculation for Standby Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the production of sulfuric acid via the contact process, maintaining the device at elevated temperatures during production stops and startups is challenging, requiring heated and dried atmospheric air, which necessitates large sulfuric acid storage and risks corrosion if moisture enters the system.
Innovation Solution
The process involves circulating process gases through a heating stage, second oxidation stage, and absorption stage during standby mode, eliminating the need for external air supply and preventing condensation, using the existing process gas heated to maintain catalyst activation temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heated and dried atmospheric air is used to keep the device warm during production stops, then the device components are maintained at elevated temperatures, but large quantities of concentrated sulfuric acid are required and corrosion risks increase
Solution Approach 1:
The process gas itself is used as the heating medium to maintain device temperature during production stops. The hot process gas from the absorption stage is recirculated through the heating stage and back to the second oxidation stage, allowing the system to self-heat without requiring external sulfuric acid for drying purposes
Solution Approach 2:
Instead of discarding the process gas after absorption, it is recovered and recirculated through the heating stage to provide heating functionality. This recovered hot gas is then fed back to the second oxidation stage, eliminating the need for separate drying operations
2Object-affected harmful factors
If concentrated sulfuric acid is used for air drying to prevent corrosion, then moisture is removed from the air, but large sulfuric acid tanks are required and maintaining concentration limits is problematic
Solution Approach 1:
The system uses its own hot process gas to provide heating and prevent condensation during production stops, eliminating the need for external sulfuric acid drying systems and large storage tanks
Solution Approach 2:
The heating function is extracted from the sulfuric acid drying system and integrated into the process gas recirculation loop, separating the heating function from the need for large quantities of concentrated sulfuric acid
3Productivity
If the catalyst is heated to activation temperature during startup, then catalytic oxidation can proceed, but the equipment must be kept warm during production stops to prevent condensation
Solution Approach 1:
The process gas recirculation system maintains continuous heating action during production stops, ensuring the catalyst remains at activation temperature without requiring continuous external energy input. The hot process gas continuously circulates through the heating stage and back to the second oxidation stage
Solution Approach 2:
The thermal energy in the process gas is recovered and reused to maintain catalyst temperature during standby periods, eliminating the need for separate heating systems and reducing overall energy consumption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively keeps device components warm without external air, preventing corrosion and reducing the need for large sulfuric acid storage, while maintaining catalyst activation temperature, thus simplifying and cost-reducing the operation.
Implementation Method 1
at least one heating stage arranged upstream of the second oxidation stage in the flow direction of the process gases is activated for heating the process gases
Implementation Method 2
sulfur dioxide is catalytically oxidized to sulfur trioxide in a second oxidation stage
Implementation Method 3
sulfur dioxide is catalytically oxidized to sulfur trioxide in a second oxidation stage
Implementation Method 4
the sulfur trioxide is introduced into at least one absorption stage for absorption
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for producing sulfuric acid, wherein, in a production mode of the method, sulfur is oxidized in a first oxidation stage in order to produce sulfur dioxide and wherein the sulfur dioxide is catalytically oxidized in a second oxidation stage in order to produce sulfur trioxide. The sulfur trioxide is absorbed in at least one absorption stage. In the production mode, process gases are discharged from the absorption stage that is last in the flow direction. In a stand-by mode of the method, at least one heating stage for heating the processes gases is activated. The process gases exiting the absorption stage are conducted to the heating stage, and the processes gases are circulated through the heating stage, the second oxidation stage, and the absorption stage.