SO2 Purification Without Gas Drying
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Solution Overview
Problem
Existing methods for converting SO2 to SO3 in gas cleaning processes require prior gas drying, which is energy-intensive and costly, and involve complex apparatus for condensing sulfuric acid mist, limiting the SO2 content and increasing operational expenses.
Innovation Solution
A continuous process that catalytically oxidizes SO2-containing gases with high water content to SO3 without prior drying, using a tubular contact apparatus with a heat exchanger and intermediate heat transfer circuit, where air or oxygen-enriched air is added to maintain high temperatures and prevent acid dew point formation, eliminating the need for acid condensation and gas drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gas drying is performed before SO2 oxidation, then corrosion of apparatus walls is reduced, but energy consumption increases and operational cost increases
Solution Approach 1:
The invention changes the temperature parameter throughout the process to prevent acid dew point formation. By maintaining temperatures above the dew point of sulfuric acid and sulphurous acid (through preheating to 380-480°C and continuous heating during oxidation), the system avoids condensation and corrosion without requiring gas drying, thus resolving the contradiction between reducing corrosion and minimizing energy consumption.
Solution Approach 2:
The invention applies preliminary heating before the oxidation reaction occurs. The rich gas is preheated to 380-480°C before entering the oxidation zone, which ensures that the temperature remains above the acid dew point throughout the subsequent oxidation process. This preliminary action prevents condensation and corrosion from the outset, eliminating the need for energy-intensive gas drying while protecting the apparatus.
2Object-affected harmful factors
If gas drying is performed to prevent sulfuric acid formation, then apparatus corrosion is reduced, but device complexity increases due to required drying equipment
Solution Approach 1:
The invention eliminates the need for complex gas drying equipment by changing the temperature parameter control strategy. Instead of removing water through drying equipment, the system maintains temperatures above the acid dew point through preheating and continuous heating during oxidation. This parameter-based approach simplifies the device by replacing complex drying and condensation equipment with a heating system.
3Quantity of substance
If high SO2 content gas is oxidized without drying, then sulfuric acid mist forms and requires complex removal measures, but gas drying is energy-intensive
Solution Approach 1:
The invention changes the temperature parameter to prevent sulfuric acid mist formation. By maintaining the oxidation zone temperature at 380-480°C and ensuring continuous heating, the system keeps the temperature above the dew point of sulfuric acid throughout the oxidation process. This prevents condensation and mist formation, allowing high SO2 conversion without generating harmful sulfuric acid mist that would require complex removal measures.
4Productivity
If catalyst temperature is maintained for optimal activity, then SO2 oxidation efficiency increases, but thermal damage to catalyst may occur
Solution Approach 1:
The invention applies continuous heating during the oxidation process to maintain the catalyst at its optimal temperature range. The heating is sustained throughout the oxidation zone, ensuring the catalyst remains active without experiencing temperature fluctuations that could cause thermal damage. This continuous thermal management enables high SO2 oxidation rates while preserving catalyst stability and extending its service life.
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 process achieves high SO2 conversion rates (70% to 99.9%) to SO3 with reduced corrosion and operational complexity, eliminating the need for acid condensation and gas drying, resulting in a cost-effective and energy-efficient method for SO2 cleaning.
Implementation Method 1
a catalyst being filled in the inner tubes and the heat transfer around these inner tubes being carried out in the space between the inner and outer tubes
Implementation Method 2
oxidation of the SO2 to SO3 in a tube contactor
Implementation Method 3
the heat transfer around these inner tubes being carried out in the space between the inner and outer tubes by a medium
Implementation Method 4
The heat released during the oxidation of SO2 to SO3 is then dissipated by the medium in the space between the inner and outer tube of the tube contactor via an intermediate circuit
Implementation Method 5
one or more wet electrostatic precipitators
Data Source
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AI summary
The invention relates to a continuous process for purifying a gas containing 60-99 percent SO2 (sulfur dioxide) by volume and 1 to 40 percent steam by volume, followed by synthesis of SO3 (sulfur trioxide) without first drying the gas, and to an apparatus for carrying out said method.