Sulfuric Acid Absorption Bypass for Heat Recovery
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Solution Overview
Problem
The existing heat recovery systems in sulfuric acid production face inefficiencies due to the need for acid concentration adjustments and water management, leading to uncontrolled dilution and increased steam production, which complicates the design and operation of heat exchangers and steam recovery.
Innovation Solution
A bypass conduit is introduced to direct a partial stream of SO3 from the primary absorber to the secondary absorber, eliminating the need for acid exchange between circuits and allowing for concentration adjustments, thereby simplifying the system and reducing the risk of acid dilution, while also optimizing steam production by operating the drying tower with higher acid concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acid exchange between circuits is performed to manage water concentration, then water balance is maintained, but system complexity and risk of uncontrolled dilution increase
Solution Approach 1:
The invention extracts the problematic acid exchange operation between circuits and replaces it with a direct water injection method into the absorber. This eliminates the complex piping and pumping systems required for acid exchange while maintaining reliable concentration control through controlled water addition.
Solution Approach 2:
The invention changes the control parameter from acid concentration adjustment through exchange to direct water quantity control in the absorber. By controlling the amount of water injected into the absorber, the system maintains acid concentration reliability without requiring complex acid exchange infrastructure.
2Productivity
If hot absorption is performed in two stages, then absorption efficiency is improved, but heat recovery complexity increases
Solution Approach 1:
The invention merges the heat recovery function with the two-stage absorption process by using the heat exchanger to preheat the absorption acid using cooled acid from the second stage. This integration improves absorption efficiency while managing heat recovery without requiring separate complex heat recovery systems.
3Quantity of substance
If acid temperature is increased for hot absorption, then absorption capacity is improved, but steam production increases requiring larger heat exchangers
Solution Approach 1:
The invention utilizes the phase transition of water to steam in the heat exchanger to manage the heat generated by hot absorption. The heat exchanger converts excess thermal energy into steam, allowing the system to maintain high acid temperatures for improved absorption capacity while controlling steam production through heat exchange.
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 solution enhances heat recovery efficiency by minimizing acid exchange, reducing the complexity of piping and pumping requirements, and allowing for flexible operation even with deviations in air humidity, while increasing high-pressure steam yield and reducing cooling water heat dissipation.
Implementation Method 1
SO3 is introduced into a first absorption stage and absorbed there in concentrated sulfuric acid
Implementation Method 2
The absorption of SO3 in sulfuric acid is an exothermal process, in which a great amount of heat is released
Implementation Method 3
the sulfuric acid, which has a higher concentration due to the absorption, is passed through a heat exchanger and cooled
Data Source
AI summary
There are described a process and a plant for producing sulfuric acid by catalytic oxidation of SO2 to SO3 and subsequent absorption of SO3 in sulfuric acid, wherein the SO3 is introduced into a first absorption stage and absorbed there in concentrated sulfuric acid, wherein the sulfuric acid having a higher concentration due to the absorption is passed through a heat exchanger and cooled, and wherein the non-absorbed SO3 is supplied to a second absorption stage for the further absorption in sulfuric acid. Before the first absorption stage a partial stream of SO3 is branched off and supplied directly to the second absorption stage.