Fe2O3-TiO2 Catalyst for Deep H2S Oxidation
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Solution Overview
Problem
Current sulfur recovery technologies, such as the Claus process and direct oxidation methods, face challenges with high operational and investment costs, low sulfur recovery rates, and environmental pollution due to high H2S and SO2 emissions, especially when dealing with low H2S concentrations.
Innovation Solution
A process utilizing a catalyst comprising iron trioxide and anatase titanium dioxide in an isothermal reactor followed by an adiabatic reactor, with specific conditions and auxiliary agents, to achieve high selectivity and sulfur recovery rates, reducing energy consumption and emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Claus process is used for sulfur recovery from acid gas with H2S concentration ≥30%, then the sulfur recovery rate can reach 95-97%, but the investment cost and operating cost become extremely high due to the need for tail-gas treatment units and burners
Solution Approach 1:
The invention extracts and eliminates the need for complex tail-gas treatment units and burners by using a catalyst that achieves complete H2S conversion to elemental sulfur directly. The catalyst selectively promotes reaction (1) while suppressing reaction (2), so that H2S is converted to sulfur without forming SO2, making subsequent tail-gas treatment unnecessary.
Solution Approach 2:
The invention changes the catalytic reaction parameters by using a specific catalyst composition (Fe2O3-TiO2 with anatase phase) that operates at lower temperatures and selectively promotes reaction (1). This parameter change allows direct oxidation to occur without forming SO2, eliminating the need for high-temperature burners and complex treatment units.
2Ease of operation
If direct oxidation method is used for acid gas with H2S concentration ≤20%, then the process is simpler and easier to operate, but the sulfur recovery rate is limited to ≤90% and the tail-gas still contains H2S and SO2
Solution Approach 1:
The invention uses a composite catalyst material consisting of Fe2O3 and anatase TiO2. The Fe2O3 provides catalytic activity for H2S oxidation, while the anatase TiO2 support enhances selectivity by suppressing SO2 formation. This composite structure achieves both high sulfur recovery rate (≥90%) and complete H2S conversion, eliminating the need for tail-gas treatment.
3Object-generated harmful factors
If thermal incineration is used to treat H2S-containing tail-gas, then H2S is converted to SO2, but the sulfur recovery rate remains low and large amounts of flue gas are consumed causing environmental pollution
Solution Approach 1:
The invention converts the harmful H2S directly into beneficial elemental sulfur through selective catalytic oxidation. Instead of converting H2S to SO2 (which is still harmful and requires further treatment), the catalyst promotes direct formation of elemental sulfur that can be recovered and utilized. This transforms a harmful substance into a valuable resource.
4Quantity of substance
If conventional catalysts are used for H2S oxidation, then the reaction can proceed, but the catalyst selectivity is inefficient and both H2S and SO2 exist simultaneously at the outlet requiring re-treatment
Solution Approach 1:
The invention applies local quality by creating a catalyst with specific spatial and compositional characteristics. The Fe2O3-TiO2 composite catalyst has localized active sites that selectively promote reaction (1) while suppressing reaction (2). The anatase TiO2 phase creates a local chemical environment that favors direct oxidation to sulfur rather than SO2 formation, achieving high selectivity.
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 a sulfur recovery rate of ≥95% with significantly reduced energy costs and emissions, meeting environmental standards while extending the H2S concentration range for acid gas treatment, replacing conventional Claus processes with a more efficient and cost-effective method.
Implementation Method 1
The present invention relates to a process for deeply catalytically oxidizing hydrogen sulfide to element sulfur
Implementation Method 2
H2S+1/2O2 ---S+H2O ΔH(273K)=-222KJ/mol (1)
Implementation Method 3
the oxidation reaction of the H2S is strong exothermic reaction; under adiabatic condition, the reaction (1) has a temperature rise of 60°C while 1% H2S oxidizing to element sulfur
Data Source
Figure 1
AI summary
A catalyst for selectively oxidizing hydrogen sulfide to element sulfur, catalyst for burning tail-gas, and process for deeply catalytically oxidizing hydrogen sulfide to sulfur are disclosed. The catalyst for selectively oxidizing hydrogen sulfide to element sulfur is prepared by: 10-34% of iron trioxide and 60-84% of anatase titanium dioxide, and the balance being are auxiliary agents. Also a catalyst for burning tail-gas is prepared by: 48-78% of iron trioxide and 18-48% of anatase titanium dioxide, and the balance being auxiliary agents. The catalyst of the present invention has high selectivity and high sulfur recovery rate. An isothermal reactor and an adiabatic reactor of the present invention are connected in series and are filled with the above two catalysts for reactions, thus reducing total sulfur in the vented gas while having a high sulfur yield and conversion rate.