Sulfur Combustion Recycle System for NOx Suppression
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Solution Overview
Problem
Existing sulfuric acid production processes face challenges in reducing equipment size and complexity, minimizing power consumption, and suppressing nitrogen oxide (NOx) formation, particularly when using oxygen for sulfur combustion.
Innovation Solution
The implementation of a system that recycles both a portion of the combustion gas from sulfur combustion to sulfur dioxide and a portion of the gases after the conversion of sulfur dioxide to sulfur trioxide or sulfur dioxide liquid, allowing for operation at moderate temperatures to suppress NOx formation and reduce equipment size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oxygen is used for sulfur combustion to produce sulfur dioxide, then sulfur dioxide concentration is improved, but nitrogen oxide (NOx) formation increases
Solution Approach 1:
The patent applies parameter changes by controlling the combustion temperature to remain below 1500°C, which suppresses NOx formation while maintaining high sulfur dioxide concentration. This temperature parameter control resolves the contradiction between producing high concentrations of SO2 and minimizing NOx formation.
2Productivity
If high temperature combustion is used to produce sulfur dioxide, then sulfur dioxide production efficiency is improved, but equipment size and complexity increase
Solution Approach 1:
The patent changes the temperature parameter to operate below 1500°C, which allows for reduced equipment size and simplified design while maintaining efficient sulfur dioxide production. This parameter adjustment resolves the contradiction between production efficiency and equipment complexity.
3Object-generated harmful factors
If combustion temperature is reduced to suppress NOx formation, then nitrogen oxide formation is minimized, but sulfur dioxide production efficiency decreases
Solution Approach 1:
The patent employs feedback mechanisms through recycle streams that return unconverted sulfur and combustion gases back to the combustion chamber, maintaining optimal temperature and sulfur dioxide concentration while suppressing NOx formation. This feedback system resolves the contradiction between minimizing NOx and maintaining production efficiency.
4Quantity of substance
If oxygen is used instead of air for sulfur combustion, then sulfur dioxide concentration is improved, but power consumption increases
Solution Approach 1:
The patent changes the combustion temperature parameter to below 1500°C, which reduces the energy input required while maintaining high sulfur dioxide concentration through oxygen combustion. This parameter control resolves the contradiction between SO2 concentration and power 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 approach results in reduced equipment size and complexity, lower power consumption, and improved energy efficiency, while minimizing NOx formation and maintaining high sulfur dioxide concentrations.
Implementation Method 1
combusting a supply of sulfur with ambient air
Implementation Method 2
oxidizing the sulfur dioxide with oxygen in the presence of a catalyst
Implementation Method 3
in the presence of a catalyst (typically vanadium oxide) to accelerate the reaction
Implementation Method 4
The produced sulfur trioxide is then converted to sulfuric acid by absorption into a concentrated sulfuric acid solution
Implementation Method 5
a reactor gases heat exchanger for cooling reactor outlet gases
Implementation Method 6
recycles both a portion of the combustion gas obtained from combusting sulfur to sulfur dioxide and also a portion of the gases obtained following the conversion of sulfur dioxide
Data Source
AI summary
Improved systems and methods are disclosed for producing sulfuric acid or for producing liquefied sulfur dioxide. The systems comprise a reactor for the combustion of sulfur to sulfur dioxide, a reactor gases heat exchanger, and either a contact apparatus and absorption apparatus combination or an absorption subsystem and liquefaction apparatus combination for producing either sulfuric acid or liquid sulfur dioxide respectively. By appropriately incorporating two recycle circuits, the first after the reactor gases heat exchanger and the second after the absorption apparatus or liquefaction apparatus, several advantages can be obtained. These include reductions in equipment size, complexity, power consumption energy losses, and suppression of NOx.