Calcium Looping Combustion for Sour Gas Sulfur Removal
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Solution Overview
Problem
The combustion of sour gas in existing processes is hindered by its corrosive nature and low calorific value, and the costly pretreatment required to remove hydrogen sulfide (H2S) makes it inefficient and costly, limiting its use in power generation.
Innovation Solution
A calcium-based chemical looping combustion (CLC) process that in-situ removes sulfur from sour gas, utilizing calcium-based oxygen carriers to oxidize the fuel stream, producing a product gas stream that can be fully converted for power generation, reducing reaction time and reactor size, and minimizing energy penalties for CO2 capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional pretreatment processes (amine gas treating) are used to remove H2S from sour gas, then sulfur removal efficiency is improved, but process complexity and cost increase significantly
Solution Approach 1:
The harmful H2S component is extracted and removed from the sour gas stream through chemical reaction with calcium oxide, separating the harmful substance from the useful fuel gas. This is achieved by injecting CaO into the combustion chamber where it reacts with H2S to form calcium sulfide, effectively removing the harmful component while allowing the rest of the sour gas to be combusted for energy production.
Solution Approach 2:
Calcium oxide serves as an intermediary substance that facilitates the removal of H2S from sour gas. The CaO acts as a mediating agent that reacts with H2S to form CaS, which can then be separated from the gas stream. This intermediary approach simplifies the overall process compared to conventional amine treating systems while achieving effective sulfur removal.
2Power
If sour gas is directly combusted in gas turbine systems, then energy production is achieved, but corrosive damage to mechanical parts occurs and H2S oxidation produces sulfur oxide pollution
Solution Approach 1:
The harmful H2S component is converted into a beneficial removal mechanism through its reaction with calcium oxide. Instead of allowing H2S to cause corrosion and pollution, the system uses CaO to chemically bind H2S, converting the harmful substance into removable calcium sulfide. This transforms the problem of H2S presence into an opportunity for effective sulfur removal while maintaining energy production from the remaining fuel gas.
Solution Approach 2:
The combustion process is segmented into distinct zones: a first combustion chamber where sour gas reacts with calcium oxide to remove H2S, and a second combustion chamber where the treated gas is combusted for energy production. This segmentation allows separate handling of sulfur removal and energy generation, preventing corrosive damage and pollution while maintaining efficient power production.
3Quantity of substance
If H2S content in sour gas is above 5-20%, then the gas contains significant energy, but direct combustion becomes impossible due to composition and physical characteristics
Solution Approach 1:
Preliminary treatment of the sour gas is performed by reacting it with calcium oxide in the first combustion chamber to remove H2S before the gas enters the second combustion chamber for energy production. This preliminary action makes the subsequently combustible gas free from corrosive H2S, enabling safe and efficient combustion of gases that would otherwise be too corrosive to burn directly.
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
The process achieves full conversion of sour gas, reduces reaction time and reactor size, and minimizes energy and cost penalties, while reducing NOx formation and avoiding costly pretreatment, enabling efficient and cost-effective energy production.
Implementation Method 1
CaO(s)+H2S(g)→CaS(s)+H2O(g)
Implementation Method 2
2CaS(s)+3O2(g)→2CaO(s)+2SO2(g)
Implementation Method 3
a calcium-based looping combustion of sour gas process involving the in-situ removal of sulfur from the sour gas
Implementation Method 4
produce heat, steam, or power from the combustion of sour gas
Data Source
Figure 1
AI summary
A calcium looping combustion process for sour gas combustion comprising a system that includes several reaction zones. The system is configured to provide oxygen transfer media production, generation of a syngas product stream, and in- situ H2S removal from the sour gas. The system is also configured such that the calcium- based transfer media and the calcium-based oxygen carrier are reproduced via reactions in another reaction zone, and recirculated in the system.